Updated on 2024/10/07

写真a

 
FUKUI Satoshi
 
Organization
Academic Assembly Institute of Science and Technology JOUHOU DENSHI KOUGAKU KEIRETU Professor
Faculty of Engineering Department of Engineering Professor
Title
Professor
External link

Degree

  • 博士(工学) ( 1997.3   横浜国立大学 )

Research Interests

  • 超伝導工学

  • High Temperature Superconducting Rotational Machines

  • 電磁気応用

Research Areas

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Power engineering

Research History (researchmap)

  • Niigata University   Faculty of Engineering   Professor

    2014.4

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    Country:Japan

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  • Niigata University   Faculty of Engineering   Associate Professor

    2007.4 - 2014.3

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    Country:Japan

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  • Niigata University   Graduate School of Science and Technology   Associate Professor (as old post name)

    2002.4 - 2007.3

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    Country:Japan

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  • NAGOYA INDUSTRIAL SCIENCE RESERCH INSTITUTE

    2000.4

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    Country:Japan

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  • Niigata University   Faculty of Engineering   Associate Professor (as old post name)

    1999.5 - 2002.3

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    Country:Japan

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  • Niigata University   Graduate School of Science and Technology   Research Assistant

    1998.4 - 1999.3

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    Country:Japan

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  • Niigata University   Faculty of Engineering   Research Assistant

    1997.4 - 1998.3

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    Country:Japan

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Research History

  • Niigata University   Faculty of Engineering Department of Engineering   Professor

    2017.4

  • Niigata University   Abolition organization Electrical Energy Systems   Professor

    2014.4 - 2017.3

  • Niigata University   Graduate School of Science and Technology Electrical and Information Engineering   Associate Professor

    2010.4 - 2014.3

  • Niigata University   Faculty of Engineering Department of Electrical and Electronic Engineering   Associate Professor

    2010.4 - 2014.3

  • Niigata University   Graduate School of Science and Technology Information Science and Engineering   Associate Professor

    2004.4 - 2010.3

  • Niigata University   Faculty of Engineering Department of Electrical and Electronic Engineering   Associate Professor (as old post name)

    1999.5 - 2002.3

  • Niigata University   Faculty of Engineering   Research Assistant

    1997.4 - 1998.4

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Education

  • Yokohama National University   大学院工学研究科博士後期課程   電子情報工学専攻

    1994.4 - 1997.3

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    Country: Japan

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  • Yokohama National University   大学院工学研究科博士前期課程   電子情報工学専攻

    1992.4 - 1994.3

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    Country: Japan

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  • Yokohama National University   工学部   電子情報工学科

    1988.4 - 1992.3

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    Country: Japan

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Professional Memberships

Committee Memberships

  • 電気学会   電力・エネルギー部門 役員会 委員・研究調査担当  

    2024.6   

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    Committee type:Academic society

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  • 電気学会   電力・エネルギー部門 研究調査運営委員会 副委員長  

    2024.6   

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  • 電気学会   磁気力を活用した脱炭素・環境再生技術と超電導応用調査専門委員会 委員  

    2023.9   

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    Committee type:Academic society

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  • 新潟電飾防止対策協議会   顧問  

    2023.4   

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    Committee type:Other

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  • 電気学会   電磁界解析による回転機の高精度モデリングと先進最適化技術調査専門委員会 委員  

    2022.4   

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  • 電気学会   希土類系高温超電導コイルの劣化対策調査専門委員会 委員  

    2021.12   

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    Committee type:Academic society

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  • 電気学会   東京支部新潟支所 支所長  

    2021.5 - 2023.5   

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    Committee type:Academic society

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  • 電気学会   東京支部役員会 協議員  

    2021.5 - 2023.5   

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  • 低温工学・超電導学会   超電導回転機の冷却技術に関する調査研究会 幹事  

    2021.4   

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  • 日本機械工業連合会   優秀省エネ脱炭素機器・システム審査幹事会 幹事  

    2021.4 - 2023.3   

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    Committee type:Other

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  • 電気学会   令和2年基礎・材料・共通部門大会実行委員会 委員  

    2020.1 - 2020.12   

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  • 電気学会   電磁界解析による回転機の高精度性能評価技術調査専門委員会 委員  

    2019.4 - 2022.3   

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    Committee type:Academic society

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  • 電気学会   磁気力を活用した新たな環境技術のフィージビリティと超電導の役割調査専門委員会 委員  

    2018.9 - 2022.8   

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    Committee type:Academic society

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  • 新エネルギー・産業技術総合開発機構   NEDO技術委員  

    2018.8 - 2020.7   

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    Committee type:Government

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  • 電気学会   編修専門第1部会 委員  

    2018.4 - 2023.3   

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    Committee type:Academic society

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  • 電気学会   超電導バルクの産業応用調査専門委員会 委員  

    2017.4 - 2019.3   

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    Committee type:Academic society

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  • 電気学会   回転機電磁界解析の実用的総合評価技術調査専門委員会 委員  

    2016.4 - 2019.3   

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    Committee type:Academic society

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  • 電気学会   代議員  

    2016.3 - 2018.2   

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  • 電気学会   超電導回転機の現状と将来動向調査専門委員会 委員  

    2015.10 - 2017.9   

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  • 電気学会   除染技術への超電導磁気力制御法の適用調査専門委員会 幹事  

    2015.7 - 2018.6   

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    Committee type:Academic society

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  • 電気学会   次世代高温超電導線材のコイル化技術調査専門委員会 委員  

    2015.7 - 2017.6   

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  • 電気学会   平成27年電力・エネルギー部門大会論文委員会 委員長  

    2014.10 - 2015.9   

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  • 電気学会   平成27年電力・エネルギー部門大会実行委員会 委員  

    2014.10 - 2015.9   

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  • 電気学会   電力・エネルギー部門表彰委員会 委員  

    2014.8 - 2015.5   

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    Committee type:Academic society

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  • 電気学会   電力・エネルギー部門編修委員会 副委員長  

    2014.6 - 2015.5   

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  • 電気学会   平成26年電力・エネルギー部門大会論文委員会 幹事  

    2013.9 - 2014.9   

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  • 電気学会   電力・エネルギー部門編修委員会 編修長  

    2013.7 - 2014.6   

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  • 電気学会   医療・バイオ・環境分野における磁気力制御技術協同研究委員会 委員  

    2013.6 - 2014.5   

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    Committee type:Academic society

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  • 電気学会   回転機電磁界解析に関する高度先端技術調査専門委員会 委員  

    2013.4 - 2016.3   

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  • 電気学会   イットリウム系高温超電導コイル化技術調査専門委員会 幹事  

    2013.4 - 2015.3   

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  • 電気学会   平成25年電力・エネルギー部門大会論文委員会 幹事  

    2013.4 - 2013.9   

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  • 電気学会   平成25年電力・エネルギー部門大会実行委員会 委員長  

    2012.11 - 2013.10   

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    Committee type:Academic society

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  • 電気学会   電力・エネルギー部門編修委員会 編修長補佐  

    2012.7 - 2013.6   

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  • 電気学会   超電導磁気分離システムを利用した除染技術調査専門委員会 幹事  

    2012.6 - 2015.5   

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    Committee type:Academic society

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  • 電気学会   電力・エネルギー部門役員会 委員・編修担当  

    2012.5 - 2016.5   

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  • 電気学会   平成24年電力・エネルギー部門大会論文委員会 主査  

    2011.10 - 2012.9   

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    Committee type:Academic society

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  • 電気学会   ICEE2012論文委員会 委員  

    2011.9 - 2012.10   

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  • 電気学会   英文論文誌編修委員会 委員  

    2011.4 - 2016.5   

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    Committee type:Academic society

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  • 電気学会   回転機の三次元電磁界解析実用化技術調査専門委員会 委員  

    2011.4 - 2013.3   

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    Committee type:Academic society

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  • 電気学会   論文委員会(B2グループ) 主査  

    2011.4 - 2012.3   

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    Committee type:Academic society

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  • 電気学会   平成23年電力・エネルギー部門大会論文委員会 副主査  

    2010.10 - 2011.9   

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    Committee type:Academic society

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  • 電気学会   電力・エネルギー部門編修委員会 委員  

    2010.7 - 2012.6   

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    Committee type:Academic society

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  • 電気学会   論文委員会(B2グループ) 副主査  

    2010.4 - 2011.3   

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    Committee type:Academic society

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  • 電気学会   平成22年電力・エネルギー部門大会論文委員会 幹事  

    2009.10 - 2010.9   

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    Committee type:Academic society

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  • 電気学会   磁気力制御を利用した超電導技術の実用化と新たな展開調査専門委員会 委員・幹事  

    2009.6 - 2012.5   

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  • 電気学会   超電導電力機器とシステムの高性能・多機能化調査専門委員会 委員  

    2009.5 - 2012.4   

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  • 国際超電導産業技術研究センター   磁場中高臨界電流線材作製技術開発及び高強度・高Je線材作製技術開発小委員会 委員  

    2009.4 - 2010.3   

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    Committee type:Other

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  • 電気学会   平成21年電力・エネルギー部門大会論文委員会 幹事  

    2008.10 - 2009.11   

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  • 国際超電導産業技術研究センター   線材特性の把握及び低交流損失線材作製技術開発小委員会 委員  

    2008.4 - 2009.3   

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    Committee type:Other

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  • 電気学会   平成20年電力・エネルギー部門大会論文委員会 幹事  

    2007.10 - 2008.9   

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    Committee type:Academic society

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  • 電気学会   大型超電導機器技術調査専門委員会 委員  

    2007.6 - 2009.5   

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    Committee type:Academic society

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  • 電気学会   次世代電力システムにおける直流給配電調査専門委員会 委員  

    2007.4 - 2010.3   

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    Committee type:Academic society

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  • 電気学会   平成19年電力・エネルギー部門大会論文委員会 委員  

    2006.10 - 2007.9   

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    Committee type:Academic society

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  • 電気学会   物質の磁気特性を活用した精密磁気制御応用技術調査専門委員会 委員  

    2006.6 - 2009.5   

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    Committee type:Academic society

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  • 電気学会   平成18年電力・エネルギー部門大会論文委員会 委員  

    2005.10 - 2006.9   

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  • 電気学会   論文委員会(B2グループ) 幹事  

    2005.4 - 2010.3   

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    Committee type:Academic society

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  • 電気学会   超電導応用機器設計基礎技術調査専門委員会 委員  

    2004.4 - 2007.3   

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    Committee type:Academic society

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  • 電気学会   交流超電導技術適用性調査専門委員会 幹事補佐  

    2002.4 - 2004.3   

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    Committee type:Academic society

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  • 超電導発電関連機器・材料技術研究組合   試験法WG 委員  

    2001.4 - 2004.3   

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    Committee type:Other

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  • 電気学会   超電導応用機器実用化動向調査専門委員会 委員  

    2000.6 - 2003.5   

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    Committee type:Academic society

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  • 電気学会   交流超電導機器技術調査専門委員会 幹事補佐  

    1999.4 - 2002.3   

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  • (財)大阪科学技術センター付属ニューマテリアルセンター   新発電システム用超電導材料標準化調査委員会 金属系超電導材料分科会 委員,交流許容WG副主査  

    1998.4 - 2003.3   

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    Committee type:Other

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  • (株)テクノバ   超電導電力応用技術開発調査研究 超電導発電機推進小委員会 超電導発電機導入効果WG 委員  

    1998.4 - 1999.3   

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    Committee type:Other

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  • 電気学会   交流超電導マグネット技術調査専門委員会 幹事補佐  

    1998.4 - 1999.3   

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  • 低温工学・超電導学会   超電導応用研究会運営委員会 委員  

    1997.11   

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    Committee type:Academic society

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Papers

  • Test of High Temperature Superconducting REBCO Coil Assembly for a Multi-Frequency ECR Ion Source Reviewed International journal

    Tsun Him Chong, Mitsuhiro Fukuda, Tetsuhiko Yorita, Hiroki Kanda, Shigeo Nagaya, Atsushi Ishiyama, So Noguchi, Hiroshi Ueda, Satoshi Fukui, Tomonori Watanabe, Jun Yoshida, Takashi Hirayama, Yukio Mikami, Yuji Matsubara, Takashi Kitamura

    IEEE Transactions on Applied Superconductivity   2024.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TASC.2024.3360935

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  • AC Loss Estimation Model for High-Temperature Superconducting Cables Derived From Experiments Simulating Electromagnetic Environments Reviewed

    J. Ogawa, S. Fukui, R. Iida, T. Obana

    IEEE Transactions on Applied Superconductivity   33 ( 5 )   2023.8

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    Publishing type:Research paper (scientific journal)  

    In a previous study, the AC loss characteristics of each layer of a high-temperature superconducting (HTS) AC cable were experimentally investigated (Ogawa et al., 2020; Ogawa et al., 2017; Ogawa et al., 2019). Based on these data, we modeled the AC loss in a superconducting cable by considering the maxi-mum and minimum values of the loss. A comparison between this model and the experimental data showed good agreement. Hence, it is possible to estimate AC loss under electromagnetic conditions in a high-temperature superconducting cable. This model makes it possible to determine the losses of each layer in the superconducting cable and to design the minimum AC loss load of the superconducting cable. This model estimates the AC losses of a three-layer twisted HTS cable.

    DOI: 10.1109/TASC.2023.3243568

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  • Development of 400 kW Class Aluminum Billet Heater Using HTS Magnet Reviewed

    Tetsuya Ito, Satoshi Fukui, Hiroshi Kawashima, Yasuhiro Ogata, Takayuki Sho, Mitsuho Furuse, Shigeo Nagaya, Tomonori Watanabe, Jun Ogawa, Yuki Morishita, Takashi Nagaoka, Nobuyuki Fuyama, Norio Nawachi

    IEEE Transactions on Applied Superconductivity   33 ( 5 )   1 - 5   2023.8

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    Publishing type:Research paper (scientific journal)   Publisher:Institute of Electrical and Electronics Engineers (IEEE)  

    DOI: 10.1109/tasc.2023.3241576

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  • Noncontact Evaluation of HTS Cylinder for Compact Cryogen-Free NMR Reviewed

    Jun Ogawa, Satoshi Fukui, Tomohiro Nabeya, Kazuhiko Toshima, Yousuke Yanagi, Kenji Kawashima

    IEEE Transactions on Applied Superconductivity   33 ( 5 )   1 - 4   2023.8

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    Publishing type:Research paper (scientific journal)   Publisher:Institute of Electrical and Electronics Engineers (IEEE)  

    DOI: 10.1109/tasc.2023.3244118

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  • Development of 400 kW-class DC Induction Heating Device Using HTS Magnet for Aluminum Extrusion Process: Continuous Repetitive Heating Test and Evaluation of Soundness of HTS Magnet Reviewed

    Tetsuya ITO, Satoshi FUKUI, Hiroshi KAWASHIMA, Yasuhiro OGATA, Takayuki SHO, Mitsuho FURUSE, Tomonori WATANABE, Shigeo NAGAYA, Jun OGAWA, Yuki MORISHITA, Takashi NAGAOKA, Nobuyuki FUYAMA, Norio NAWACHI

    TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)   58 ( 3 )   124 - 131   2023

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    Publishing type:Research paper (scientific journal)   Publisher:Cryogenic Association of Japan  

    DOI: 10.2221/jcsj.58.124

    J-GLOBAL

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  • Fabrication and Test of HTS Magnet for Induction Heating Device in Aluminum Extrusion Processing Reviewed

    Tetsuya Ito, Satoshi Fukui, Hiroshi Kawashima, Yasuhiro Ogata, Mitsuho Furuse, Tomonori Watanabe, Shigeo Nagaya, Jun Ogawa

    IEEE Transactions on Applied Superconductivity   32 ( 4 )   1 - 5   2022.6

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    Publishing type:Research paper (scientific journal)   Publisher:Institute of Electrical and Electronics Engineers (IEEE)  

    DOI: 10.1109/tasc.2021.3136801

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  • Novel magnetizing technique using high temperature superconducting bulk magnets for permanent magnets in interior permanent magnet rotors Reviewed

    T. Oka, S. Hasebe, J. Ogawa, S. Fukui, T. Nakano, N. Sakai, M. Miryala, M. Murakami, K. Yokoyama

    Superconductor Science and Technology   33 ( 8 )   2020.8

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    Publishing type:Research paper (scientific journal)  

    A novel magnetizing technique for permanent magnets (PMs) embedded in interior permanent magnet (IPM) motors has been proposed as a safer and more effective process than the conventional processes using copper pulse-coils. In the new process, the high temperature superconducting (HTS) bulk magnet, emitting an intense magnetic field of over 3 T, was employed to activate the rotor and PMs inside. A magnetic pole containing the HTS bulk magnet was scanned on the surface of the IPM rotor, resisting against the extremely strong attractive force between the magnet and rotor. Following experiments in the past, numerical simulation studies have been conducted to evaluate the magnetic field-trapping performances of the PMs. In this study, the numerical analysis of the magnetization behaviours was conducted for the PMs embedded in the rotor of the commercial air-conditioner motor in a hybrid car. The simulation results showed us that the demagnetized Nd-Fe-B plates in the rotor were fully magnetized in the intense static magnetic fields on the magnetic pole containing the HTS bulk magnet. The magnetizing behaviour in this peculiar magnetizing operation was made understandable by estimating the anisotropic easy-direction of the PM plates embedded in the rotor. The novel activation method for PM is characterized as a no-shock and no-heating method, which would promote the degree of freedom in the IPM motor design.

    DOI: 10.1088/1361-6668/ab9543

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  • Occurrence of Flux Jumps in MgB<sub>2</sub> Bulk Magnets during Pulse-Field Magnetization Reviewed

    N Sakai, T Oka, K Yamanaka, L Dadiel, H Oki, J Ogawa, S Fukui, J Scheiter, W Häßler, K Yokoyama, J Noudem, M Miryala, M Murakami

    Journal of Physics: Conference Series   1559 ( 1 )   012024 - 012024   2020.6

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    Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    Abstract

    The magnetic flux capturing of MgB<sub>2</sub> bulk magnets made by spark plasma sintering process has been precisely investigated to clarify the mechanism of flux motions during the pulse-field magnetization processes. The field trapping ratio B<sub>T</sub>/B<sub>P</sub> was evaluated as a key parameter of field trapping ability which strongly relates to the heat generation due to the rapid flux motion in the samples. The time dependence of magnetic flux density revealed the actual flux motion which penetrated the samples. The trapped fields B<sub>T</sub> and field trapping ratios B<sub>T</sub>/B<sub>P</sub> of various samples were classified into three regions of ‘no flux flow’, ‘fast flux flow’ and ‘flux jump’ according to the generation of heat and its propagation. A flux jump was observed late at 280 ms from the beginning of PFM process, while the field penetration B<sub>P</sub> showed its peak at 10 ms. Considering the heat propagation speed, the long-delayed flux jump should be attributed to the macroscopic barriers against the heat propagation to the surface centre of bulk magnet.

    DOI: 10.1088/1742-6596/1559/1/012024

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  • Experimental Investigation of AC Loss Characteristics under HTS Cable Electromagnetic Conditions Reviewed

    Jun Ogawa, Satoshi Fukui, Naoya Koseki, Toshiki Fujii, Yuta Mihira

    IEEE Transactions on Applied Superconductivity   30 ( 4 )   1 - 5   2020.6

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    DOI: 10.1109/tasc.2020.2966421

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  • Magnetizing Technique for Permanent Magnets in IPM Motor Rotors Using HTS Bulk Magnet Reviewed

    T. Oka, S. Hasebe, J. Ogawa, S. Fukui, T. Nakano, K. Yokoyama, M. Miryala, N. Sakai, M. Murakami

    IEEE Transactions on Applied Superconductivity   30 ( 4 )   2020.6

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    A unique activation technique for permanent Nd-Fe-B magnets which were embedded in the rotors of interior permanent magnet (IPM) motors has been developed as a magnetizing tool with use of high temperature superconducting (HTS) bulk magnet. The experimental and numerical simulation studies were conducted to evaluate the magnetic field-trapping performances of the rotor of air-conditioner compressor in the hybrid-type automobiles. The sample rotor containing six demagnetized permanent magnet plates were exposed in the intense static magnetic fields above the magnetic pole which contained the bulk magnet generating over 4 T. As a result, the sample magnets were perfectly magnetized in the static magnetic field. The precise simulation on the flux distribution in the rotor clarified that it is important to make the flux direction in the rotor core and the easy magnetization axis of PM identical. We convinced this activation technique should enable us to promote the degrees of freedom of motor designing and its processing.

    DOI: 10.1109/TASC.2020.2989181

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  • Formation of uniform magnetic flux distribution for NMR magnets using HTS bulk magnets activated by pulsed-field magnetization Reviewed

    T. Oka, N. Inoue, S. Tsunoda, J. Ogawa, S. Fukui, K. Yokoyama, N. Sakai, M. Miryala, M. Murakami, M. Takahashi, T. Nakamura

    Materials Research Express   7 ( 5 )   2020.5

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    © 2020 The Author(s). Published by IOP Publishing Ltd. Nuclear magnetic resonance (NMR) magnets generally need an extremely uniform magnetic field in the space where the specimens will be placed. Although high temperature superconducting bulk magnets can obtain an intense magnetic field of more than 3 T, the field distribution is intrinsically characterized to be inhomogeneous, showing steep gradient. Aiming at the practical application of compact and portable NMR magnets, the authors have developed magnet systems capable of generating uniform magnetic fields in a narrow space between face-to-face settled magnetic poles, targeting to obtain a uniform magnetic field between the poles. Here, the authors modified the shape of magnetic field distribution from convex to concave by attaching a ferromagnetic iron plate on one of the pole surfaces, and then settled them face to face with a gap of 70 mm. The uniformity of the magnetic field in the x-y plane was experimentally measured and estimated along various z-axis directions. The best uniformity of 463 ppm at 1.25 T was obtained in the experimental evaluation in the x-y plane of 4 4 mm2 at z = 0.5 mm from the iron plate surface. The value of uniformity along the z-direction range was extended from 0.8 mm to a depth of 1.1 mm. These results show that the possible space of NMR signal detection or the available sample size can be enlarged.

    DOI: 10.1088/2053-1591/ab8e6d

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  • W-07 Human Resource Development through International Collaboration on Forefront Scientific Technologies

    OKA Tetsuo, FUKUI Satoshi, OGAWA Jun, OHMURA Ayako, ISHIKAWA Fumihiro, YOKOYAMA Kazuya, NAKA Takashi, MURAKAMI Masato

    JSEE Annual Conference International Session Proceedings   2020 ( 0 )   34 - 37   2020

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    The technology of superconductivity is regarded as the most developed in the world due to the efforts of Japanese scientists who invented multiple novel and efficient superconductors. A characteristic research activity titled international collaboration aiming at reducing ac energy loss of superconducting materials has been carried on through the international network with respect to the extreme technologies such as large current, intense magnetic field and super-high pressure. To nurture young researchers, the international collaboration project has been conducted with an assistance of Japanese government. A characteristic international collaboration project has been carried on for three years in cooperation with the European forefront institutes and promoted the research activities of young Japanese researchers to the world top level.

    DOI: 10.20549/jseeen.2020.0_34

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  • Load Test and Variable Speed Control of a 50-kW-Class Fully Superconducting Induction/Synchronous Motor for Transportation Equipment Reviewed

    Taketsune Nakamura, Masaaki Yoshikawa, Ken-Ichi Ikeda, Tomoharu Karashima, Takuro Ogasa, Ryohei Nishino, Yoshitaka Itoh, Toshihisa Terazawa, Mitsuho Furuse, Satoshi Fukui

    IEEE Transactions on Applied Superconductivity   29 ( 5 )   2019.8

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    This paper reports the design, fabrication, and test results of a 50-kW-class fully superconducting induction/synchronous motor for transportation equipment. Its maximum speed is 1800 rpm, and both rotor and stator windings were fabricated using Bismuth strontium calcium copper oxide tapes. The so-called ring-winding structure was used for the stator windings to improve the critical current of the stator windings in the core. The fabricated motor was immersed in liquid nitrogen and tested using a commercial pulse width modulation inverter. We successfully carried out a 3-kW load test at a synchronous speed of 1800 rpm. Furthermore, a variable speed test under light load conditions was also completed.

    DOI: 10.1109/TASC.2019.2902504

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  • Study on Magnetic Flux Dissipation and Field-Trapping Performance of HTS Bulk-Shaped Magnesium Diboride in Pulse-Field Magnetizing Processes Reviewed

    T. Oka, A. Takeda, H. Oki, J. Ogawa, S. Fukui, J. Scheiter, W. Hassler, K. Yokoyama, K. Yamanaka, L. Dadiel, M.Miryala, N. Sakai, M. Murakami, J. Noudem

    IEEE Transactions on Applied Superconductivity   29 ( 5 )   6802606 - 6802606   2019.8

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    DOI: 10.1109/TASC.2019.2908752

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  • Study on AC Loss Characteristics of 3-Phase HTS Coils With Iron Core and Its Reduction Reviewed

    S. Fukui, J. Ogawa, J. Takahashi, Y. Kobu, T. Sato

    IEEE Transactions on Applied Superconductivity   29 ( 5 )   8201305 - 8201305   2019.8

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    DOI: 10.1109/TASC.2019.2902692

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  • AC Loss in Each Layer of Three-Layer Twisted HTS Cable Reviewed

    J. Ogawa, S. Fukui, M. Sugai, S. Aoyama, N. Koseki

    IEEE Transactions on Applied Superconductivity   29 ( 5 )   5901106 - 5901106   2019.8

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    DOI: 10.1109/TASC.2019.2901213

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  • Development of an HTS Capacitor Using Bi2223/Ag Tapes as Electrodes Reviewed

    J. Ogawa, S. Fukui, K. Yoshino, Y. Suzuki, S. Torigata

    IEEE Transactions on Applied Superconductivity   29 ( 5 )   9001204 - 9001204   2019.8

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    DOI: 10.1109/TASC.2019.2898237

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  • Feasible Applications of Bulk HTS Magnets and Magnetic Field-Capturing Characteristics in Their Activation Processes Reviewed

    T. Oka, A. Takeda, K. Shimizu, K. Higa, S. Tsunoda, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, T. Nakamura

    IEEE Transactions on Applied Superconductivity   29 ( 3 )   6800706 - 6800706   2019.4

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    DOI: 10.1109/TASC.2018.2867784

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  • Magnetic Flux Invasion and Field-Capturing in Pulsed-Field Magnetization for Layered MgB2 Bulk Magnets Reviewed

    T. Oka, A. Takeda, S. Sasaki, J. Ogawa, S. Fukui, T. Sato, J. Scheiter, W. Hssler, J. Katsuki, A. Miura, K. Yokoyama

    IEEE Transactions on Applied Superconductivity   28 ( 4 )   6800504 - 6800504   2018.6

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    DOI: 10.1109/TASC.2018.2792530

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  • Modeling of Magnetization Loss in HTS Tape Exposed to All Magnetic Field Directions Reviewed

    J. Ogawa, S. Fukui, T. Oka, Yan Panpan, K. Kanamori

    IEEE Transactions on Applied Superconductivity   28 ( 3 )   8200405 - 8200405   2018.4

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    DOI: 10.1109/TASC.2017.2786708

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  • AC Loss Distribution in Two-Layer HTS Cable Reviewed

    J. Ogawa, S. Fukui, T. Oka, T.Ogawa, M. Sugai

    IEEE Transactions on Applied Superconductivity   28 ( 3 )   5900104 - 5900104   2018.4

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    DOI: 10.1109/TASC.2017.2776923

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  • A review article: Compact magnetic field generators containing HTS bulk magnets cooled by refrigerators and their feasible applications

    Tetsuo Oka, Jun Ogawa, Satoshi Fukui, Takao Sato, Tomohito Nakano, Kazuya Yokoyama, Takashi Nakamura, Hiroyuki Fujishiro, Koshichi Noto

    High-Temperature Superconductors: Occurrence, Synthesis and Applications   291 - 306   2018.1

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    Various types of strong magnetic field generators with use of HTS bulk magnets and the small-scale refrigerators have been actually proposed and experimentally estimated for the feasible applications. The most characteristic feature of bulk magnets is regarded as compact and strong field generators with respect to their magnetic field spaces or their machine structures of themselves. Among them, the magnetic flux density of the face-toface magnetic poles reached 3.2 T and 4.4 T when they were activated by the pulsed field magnetization and the field cooling method, respectively. Furthermore, a very small bulk magnet generating 2.8 T and the system featured by the wide magnetic poles containing seven magnets have been constructed with use of ST pulse tube coolers in order to expand the feasible application areas. On the other hand, although the bulk magnets are characterized by their steep field distributions, we attempted to gain the uniform magnetic field space, and successfully achieved the uniformity of 385 ppm in 4 mm range by combining the deformed magnetic field profiles which generated between the face-to-face magnetic poles. The performances of these unique systems have exceeded those of the conventional electromagnet or any permanent magnets by far, demonstrating the superiority to other strong magnetic field generators.

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  • Pulse-Field Magnetization for Disc-Shaped MgB2 Bulk Magnets Reviewed

    T. Miyazaki, S. Fukui, J. Ogawa, T. Sato, Tetsuo Oka, J. Scheiter, W. H?, ler. E. Kulawansha, Z. Yuanding, K. Yokoyama

    IEEE Transactions on Applied Superconductivity   27 ( 4 )   6800504 - 6800504   2017.6

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    DOI: 10.1109/TASC.2016.2639298

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  • Experimental Investigation of AC Loss Characteristics in HTS Tape With Rotating Magnetic Field Reviewed

    J. Ogawa, S. Fukui, T. Oka, Yuki Sano, Masahiro Ogawa, Simon T. Ranecky

    IEEE Transactions on Applied Superconductivity   27 ( 4 )   5900504 - 5900504??   2017.6

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    DOI: 10.1109/TASC.2017.2651099

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  • Magnetic Flux Invasion in REBCO Bulk Magnets with Varying Pre-Magnetized Flux Distributions in Multiple-PFM Processes Reviewed

    T. Oka, K. Hara, A. Takeda, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, A. Murakami

    Journal of Physics: Conference Series   871   012049   2017

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  • Novel Attempt to Create Uniform Magnetic-Field Space Generated by Face-to-Face Settled HTS Bulk Magnets Reviewed

    OKA Tetsuo, ICHIJU Kana, HIGA Kazuya, FUKUI Satoshi, OGAWA Jun, SATO Takao, YOKOYAMA Kazuya, NAKAMURA Takashi

    TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)   52 ( 1 )   38 - 43   2017

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    Language:Japanese   Publisher:CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN  

    <p>Various experimental attempts have been made to obtain a uniform magnetic field in the space between face-to-face HTS bulk magnets that could possibly be utilized as NMR magnets. In general, the magnetic fields emitted from the magnetic pole surfaces containing HTS bulk magnets are characterized as non-uniform field distributions. Since the NMR magnets require highly uniform magnetic-field spaces, it has been assumed to be difficult to form uniform magnetic-field spaces between magnetic poles placed face-to-face. The authors modified the shapes of the magnetic-field distribution from convex to concave by attaching ferromagnetic iron plates to the pole surfaces. The magnets were then set face-to-face with various gaps of 30-70 mm, and the experimental data on magnetic-field uniformity was precisely measured in the space. In order to detect the NMR signals, the target performance for uniformity was set as 1,500 ppm throughout the 4-mm span on the x-axis, which is equivalent to performance in the past when the world's first detection of NMR signals was observed in the bore of hollow-type HTS bulk magnets. When we combined the concave and convex field distributions to compensate the uneven field distributions, the data of the best uniformity reached 358 ppm and 493 ppm in the 30 mm and 50 mm gaps, respectively, which exceeded the target value for the purpose of detecting the NMR signals within the space. Furthermore, it was shown that the field distributions change from concave to convex shape without any change at 1.1 T in the range from 7 to 11 mm in the 30-mm gap, indicating that the distributions are uniform. This suggests the possibility that the uniform magnetic-field space between the HTS bulk magnets set face-to-face expands.</p>

    DOI: 10.2221/jcsj.52.38

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  • Study on AC Loss Reduction in HTS Coil for Armature Winding of AC Rotating Machines Reviewed

    S. Fukui, S. Tsukamoto, K. Nohara, J. Ogawa, T. Sato, T. Nakamura

    IEEE Transactions on Applied Superconductivity   26 ( 4 )   5203705 - 5203705   2016.6

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    DOI: 10.1109/TASC.2016.2535208

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  • Magnetic Field Direction Dependence of AC Losses in Bi2223/Ag Tape Reviewed

    J. Ogawa, S. Fukui, T. Oka, N. Shidara, R. Iwashita, M. Ohya

    IEEE Transactions on Applied Superconductivity   26 ( 4 )   8200204 - 8200204   2016.6

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    DOI: 10.1109/TASC.2016.2516349

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  • Experimental Investigation of AC Loss Characteristics of Stacked HTS Tapes in an Iron Core Reviewed

    J. Ogawa, S. Fukui, T. Oka, T. Sakurai, Y, Sano, H. Tada, Y. Yoshii

    IEEE Transactions on Applied Superconductivity   26 ( 4 )   5900204 - 5900204   2016.6

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    DOI: 10.1109/TASC.2016.2543504

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  • Selective Magnetic Field Invasion Into HTS Bulk Magnets in Pulse Field Magnetizing Processes Reviewed

    T. Oka, K. Hara, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, A. Murakami, M. Langer

    IEEE Transactions on Applied Superconductivity   26 ( 3 )   6800504 - 6800504   2016.4

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    DOI: 10.1109/TASC.2016.2529425

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  • Elemental Development of Metal Melting by Electromagnetic Induction Heating Using Superconductor Coils Reviewed

    Tomonori Watanabe, Shigeo Nagaya, Naoki Hirano, Satoshi Fukui

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   26 ( 3 )   2016.4

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    The billet heating technique by rotating conductive material in a magnetic field for aluminum extrusion has been reported, but metal melting technology by the induction heating with the dc magnetic field has not. Further complex geometries of aluminum profiles are formed by the casting that requires highly efficient metal melting technology. In order to verify the capability of induction heating using dc superconductor coils for metalmelting in the casting process, we performed a metalmelting experiment with the small examination equipment in a magnetic field. The small examination equipment consists of a motor, a heat insulation structure, a rotating shaft, a specimen holder, a frame, and others. An aluminum pipe of about 0.77 kg, where its outer diameter was 180 mm and its inner diameter was 170 mm, was put into the examination equipment. A dc magnetic field, ranging from about 1 T at the nearest point to 0.4 T at the furthest point, was applied to the pipe by the superconductor magnet. The temperature of aluminum exceeded 500 degrees C within 2 min by the rotation of the pipe at 800 r/min. Aluminum melting in the sample holder was observed after the rotation of 1200 r/min in 90 s, and some amounts of melted aluminum rose over the sample holder and sputtered out by centrifugal force. These results indicate that induction heating with the superconductor coils can supply melting metal of required amount in a short time.

    DOI: 10.1109/TASC.2016.2524651

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  • Magnetization behavior of RE123 bulk magnets bearing twin seed-crystals in pulsed field agnetization processes Reviewed

    T. Oka, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, M. Langer

    Superconductor Science and Technology   29 ( 2 )   24003 - 24003   2016.2

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    DOI: 10.1088/0953-2048/29/2/024003

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  • Uniform magnetic field between face-to-face HTS bulk magnets combining concave and convex magnetic field distributions Reviewed

    T. Oka, Y. Takahashi, S. Yaginuma, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, T. Nakamura

    PROCEEDINGS OF THE 28TH INTERNATIONAL SYMPOSIUM ON SUPERCONDUCTIVITY (ISS 2015)   81   45 - 48   2016

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    The authors have been attempting to obtain the uniform magnetic field distribution in the space between the face-to-face HTS bulk magnets. The magnetic poles containing the HTS bulk magnets are usually characterized as non -uniform magnetic field distribution. Since the distributions show the conical or convex shapes, it is difficult to obtain the uniform magnetic field spaces even when the magnetic poles would be placed face-to-face. The authors have modified the shape of the distribution of one-side magnetic pole by attaching an iron plate on the surface, and formed the concave magnetic field distribution on the pole surface. The steep concave or convex distributions at each pole surface change to be flat with increasing distance from the pole surface. After the experimental result recording the best uniformity of 358 ppm by combining the concave and convex field distributions face-to-face, we attempted to simulate the feasible performance in this configuration. In the numerical simulation, the concave field distribution modified by attaching an imaginary spiral coil on the pole surface was coupled with the original convex field. We succeeded in obtaining the best uniformity of 30 ppm at 1.1 T in 4 x 4 mm(2) x-y plane at 7 mm distant from the pole surface in the gap of 30 mm. This result suggests that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap, and also suggests the novel compact NMR/MRI devices in the future. (C) 2016 The Authors. Published by Elsevier B.V.

    DOI: 10.1016/j.phpro.2016.04.019

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  • Fabrication and testing of racetrack-shaped double-pancake coil for stator windings of induction-synchronous motor

    Mitsuho Furuse, Masaaki Yoshikawa, Yoshitaka Itoh, Satoshi Fukui, Taketsune Nakamura

    IEEE Transactions on Applied Superconductivity   25 ( 3 )   2015.6

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    We have fabricated a racetrack-shaped spliceless double-pancake test coil with GdBCO coated conductors and investigated its performance in air and magnetic cores. We have been developing a high-temperature superconductor induction/synchronous machine (HTS-ISM) for electric vehicles. To improve the specific power and torque density of the fully superconducting HTS-ISM, an increase in the current capacity of the HTS stator windings is crucial. The fabricated test coil was wound with two GdBCO conductors in parallel, which were transposed at a coil end. Thus, the self-inductances of the two conductors were equal, and the coil was free from splice resistances due to transposition. We confirmed the soundness of the transposition method by critical current measurements. We also investigated the critical currents of the test coil by placing it in a magnetic core and observed a decrease in the critical current compared with that in the air core. This is caused by the increase in the component of the magnetic field perpendicular to the coated conductors. To overcome this issue, magnetic materials were used for magnetic-field correction. We methodically compared the results of the critical current measurements and evaluated the results by numerical magnetic-field analyses.

    DOI: 10.1109/TASC.2014.2363041

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  • Tremendous enhancement of torque density in HTS induction/synchronous machine for transportation equipments Reviewed

    Taketsune Nakamura, Yoshitaka Itoh, Masaaki Yoshikawa, Tatsuo Nishimura, Takuro Ogasa, Naoyuki Amemiya, Yoshimasa Ohashi, Satoshi Fukui, Mitsuho Furuse

    IEEE Transactions on Applied Superconductivity   25 ( 3 )   5202304   2015.6

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    DOI: 10.1109/tasc.2014.2382337

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  • Preferential Magnetic Flux Invasion and Heat Generation Owing to Macrostructure in HTS Bulk Magnets in Pulse Field Magnetization Processes Reviewed

    T.Oka, H. Ota, T. Shimoda, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, A. Murakami, M. Langer

    IEEE Transactions on Applied Superconductivity   25 ( 3 )   6800904 - 6800904   2015.6

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    DOI: 10.1109/TASC.2014.2373653

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  • A Numerical Proposal of an After Heating Method for Pulse Field Magnetization for HTS Bulk Magnets Reviewed

    J.Ogawa, T. Oka, S. Fukui, T. Sato, N. Watanabe

    IEEE Transactions on Applied Superconductivity   25 ( 3 )   6801704A - 6801704A   2015.6

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    DOI: 10.1109/TASC.2014.2366236

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  • Numerical Study of the Influence of Material Properties on Pulsed-Field Magnetization for HTS Bulk Magnets Reviewed

    J.Ogawa, T. Oka, S. Fukui, T. Sato, N. Watanabe, M. Zulaika

    IEEE Transactions on Applied Superconductivity   24 ( 3 )   8200304 - 8200304   2014.6

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    DOI: 10.1109/TASC.2013.2282174

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  • Influence of the Arrangement of HTS Tapes Inserted in an Iron Core on AC Loss Characteristics Reviewed

    J.Ogawa, T. Oka, S. Fukui, T. Sato, A. Fushimi, T. Shoda

    IEEE Transactions on Applied Superconductivity   24 ( 3 )   6600204 - 6600204   2014.6

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    DOI: 10.1109/TASC.2013.2280730

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  • Strong Magnetic Field Generator Containing HTS Bulk Magnets and Compact Refrigerators Reviewed

    T. Oka, E. Hirayama, T. Kanai, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, T. Nakamura

    IEEE Transactions on Applied Superconductivity   24 ( 3 )   4900204 - 4900204   2014.6

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    DOI: 10.1109/TASC.2013.2284859

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  • Influence of Structural Material and Epoxy Impregnation on Coil Strains in Y123 Pancake Coil Reviewed

    T. Takao, S. Sakai, K. Ishizu, D. Nakayama, K. Nishimura, O. Sakamoto, T. Goto, A. Yamanaka, S. Fukui, A. Nishimura

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   24 ( 3 )   1 - 5   2014.6

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    Single-pancake coils having different winding turns are fabricated. The bobbin material used for the coils is a Dyneema fiber-reinforced plastic (DFRP), which has a thermal expansion property during cooling. The influence of the DFRP's expansion on thermal strains of the coil during cooling is experimentally estimated. In the experiment, the thermal strains on the superconducting tape of the outermost turns in the coils are measured. The dependence of epoxy impregnation on the thermal strain of the coil is also experimentally estimated. According to the experimental data, the combination of impregnation and the bobbin's expansion effectively decreases thermal contraction of the outermost tape.

    DOI: 10.1109/TASC.2013.2285709

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  • Collection of Ni-bearing material from electroless plating waste by magnetic separation with HTS bulk magnet Reviewed

    T. Oka, H. Fukazawa, S. Fukui, J. Ogawa, T. Sato, M. Ooizumi, M. Tsujimura, K. Yokoyama

    Physica C   496   58 - 62   2014.1

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    DOI: 10.1016/j.physc.2013.01.018

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  • Pulsed-field Invasion to HTS Bulk Magnets Grown from Two Seeds with Varied Seed-crystal Positions and Numbers Reviewed

    T. Oka, Y. Yamada, T. Horiuchi, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, M. Langer

    Physics Procedia   58   74 - 77   2014

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    © 2014 The Authors. The flux-invasion behavior into the melt-processed Y-Ba-Cu-O bulk magnets were precisely measured and analyzed during and after their pulsed-field magnetization processes operated at 30.6 K. The materials were fabricated as the bulk monoliths grown by adopting two seed-crystals, or shifting the seed-crystal positions from the centre of the sample surface, which exhibited the magnetically single-domain distributions. Although the performances of the trapped flux density after activations showed no obvious differences, the flux started invading into the sample bearing two seeds obviously at lower fields than those of normally-grown isotropic crystal. Since the flux penetration behavior were thus clearly different between the samples with the structure grown from two seeds and uniformly grown samples with a seed crystal, it is suggested that the structure results in an effective magnetizing method with less heating than those of conventional samples, which results in the higher performance of field trapping in the bulk magnets than usual.

    DOI: 10.1016/j.phpro.2014.09.021

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  • Magnetic flux-trapping of anisotropic-grown Y-Ba-Cu-O bulk superconductors during and after pulsed-field magnetizing processes Reviewed

    T. Oka, Y. Yamada, T. Horiuchi, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, M. Langer

    Journal of Physics: Conference Series   507 ( PART 1 )   2014

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    The magnetic flux penetration into the melt-textured Y-Ba-Cu-O high temperature superconducting bulk magnets were precisely evaluated during and after the pulsed field magnetization processes operated at 30 K. The bulk magnets were carefully fabricated by the cold seeding method with use of a single and a pair of seed crystals composed of the Nd-Ba-Cu-O thin films. These seed crystals were put on the top surfaces of the precursors to let the large grains grow during the heat treatments. We observed the flux penetrations which occurred in the lower applied-field regions at around 3.1 T for the samples bearing the twin seeds than those of the single-seeded crystals at around 3.8 T. This means that the magnetic fluxes are capable of invading into the twin-seeded samples more easily than the single-seeds. It suggests that the anisotropic grain growths of parallel and normal to the rows of seed crystals affects the variations of Jc values with different distributions of the pinning centers, results in the preferential paths for the invading magnetic fluxes. © Published under licence by IOP Publishing Ltd.

    DOI: 10.1088/1742-6596/507/1/012039

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  • Flux-invading behaviors and temperature changes in Dy123 bulk magnet in iterative pulse field magnetization process Reviewed

    T. Oka, D. Ishiduka, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, A. Murakami

    Physica C   494   46 - 49   2013.11

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    DOI: 10.1016/j.physc.2013.04.022

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  • Measurement and Numerical Analysis of Dependence of AC Loss in Polygonal Conductor Assembled by YBCO Tapes on Gap Length Between Neighboring Tapes Reviewed

    S. Fukui, S. Hatakeyama, J. Nanayama, A. Maruko, J. Ogawa, T. Sato, T. Oka, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   23 ( 3 )   5900105 - 5900105   2013.6

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    DOI: 10.1109/TASC.2013.2238982

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  • Mechanical Loss and Bobbin Material in Double Pancake AC Superconducting Coils Reviewed

    Tomoaki Takao, Kazuki Nishimura, Satoshi Sakai, Toshiyuki Takagi, Orie Sakamoto, Takayuki Goto, Satoshi Fukui, Atsuhiko Yamanaka

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   23 ( 3 )   2013.6

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    We fabricated nonimpregnated HTS superconducting coils with a BSCCO tape. Bobbin materials in the coils are a Dyneema(R) fiber reinforced plastic (DFRP) and a glass fiber reinforced plastic (GFRP). We excited those coils with ac currents, and estimated mechanical losses. According to the measured data, the mechanical loss decreased with increase of winding tension of the coils, because strong winding tension fixed the coils tightly. Also, the mechanical loss occurred in the DFRP coil was smaller than that occurred in the GFRP coil. A thermal expansion coefficient of the DFRP is a negative value, that is, the DFRP expands with cooling down from room temperature to cryogenic temperature. The expansion of the DFRP bobbin made the winding of the coil fix tightly, and the mechanical loss decreased. From those experimental results, we think that the DFRP bobbin is useful for decreasing of mechanical losses of the ac coils.

    DOI: 10.1109/TASC.2012.2236372

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  • Development and test of model apparatus of non-contact spin processor for photo mask production applying radial-type superconducting magnetic bearing Reviewed

    K. Saito, S. Fukui, M. Maezawa, J. Ogawa, T. Oka, T. Sato

    Physica C   484   321 - 324   2013.6

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    DOI: 10.1016/j.physc.2012.03.008

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  • Magnetic and Thermal Properties of HTS Bulk Magnet in the Pulsed-Field Magnetizing Process Reviewed

    T. Oka, D. Ishiduka, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama, A. Murakami

    Journal of Superconductivity and Novel Magnetism   26   1301 - 1306   2013.4

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    DOI: 10.1007/s10948-012-2048-5

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  • Magnetic precipitate separation for Ni plating waste liquid using HTS bulk magnets Reviewed

    T. Oka, T. Kimura, D. Mimura, H. Fukazawa, S. Fukui, J. Ogawa, T. Sato, M. Ooizumi, K. Yokoyama, M. Tsujimura, T. Terasawa

    Physica C   484   325 - 328   2013.1

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    DOI: 10.1016/j.physc.2012.03.010

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  • Magnetic Field-Trapping Properties of Melt-Processed Y123 Bulk Superconductors Activated by Pulsed-Field Magnetizing Method Reviewed

    Oka Tetsuo, Yamada Yukimasa, Ishiduka Daichi, Ogawa Jun, Fukui Satoshi, Sato Takao, Yokoyama Kazuya, Langer Marco

    Transactions of the Materials Research Society of Japan   38 ( 2 )   273 - 277   2013

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    The magnetic flux invasion into the Y-Ba-Cu-O-based high temperature superconducting bulk magnets were precisely evaluated during the pulsed field magnetization processes. Various bulk magnets with different contents of Y<sub>2</sub>BaCuO<sub>5</sub> (Y211) particles were fabricated so as to examine how the Y211 concentrations affect the flux invasion behaviors. The flux motions and the resultant trapped field densities were monitored at the surface of each bulk sample at 30.6 K. As a result, the applied fields at which the magnetic flux began to invade the sample increased with increasing Y211 contents. This means that the pinning centers are promoted with increasing nominal Y211 addition. According to the evolutional profiles during the pulsed-field applications, the flux-penetration ratio gradually promoted with increasing applied fields, whereas the flux-trapping ratio decreased. This implies that the heat generation due to the flux motion seriously affects the field-trapping ability. The anomalous behaviors for the sample, which has displaced position of seed crystal, showed us more effective flux-trapping than usual, exhibiting the higher flux-penetration and flux-trapping ratios at lower applied-field than those of other samples. This suggests a possible high-field activation method with preferential flux invasion due to the different microstructures in the bulk magnet.

    DOI: 10.14723/tmrsj.38.273

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  • Study on decontamination of radioactive cesium from soil by HTS magnetic separation system Reviewed

    Shigehiro Nishijima, Yoko Akiyama, Fumihito Mishima, Tomonori Watanabe, Tadashi Yamasaki, Shigeo Nagaya, Satoshi Fukui

    IEEE Transactions on Applied Superconductivity   23 ( 3 )   2013

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    By the accident of the Fukushima Daiichi Nuclear Plant, radioactive substances have been scattered in the environment. The decontamination of radioactive substances in the soils and the wreckage, and the volume reduction of contaminated waste are urgent issues. In this study, we examined the possibility for the soil decontamination of Cs-137, the main radioactive species with longer half-life, by means of the magnetic separation with a high-temperature superconducting magnet. We investigated the desorption behavior of the nonradioactive cesium from several kinds of clay minerals, and the removal rate by the ferromagnetic adsorbent from the aqueous phase. The results showed the possibility of the removal of cesium from the clay. Based on the results, we proposed a magnetic separation system of radioactive cesium by using high gradient magnetic separation with a superconducting magnet. © 2013 IEEE.

    DOI: 10.1109/TASC.2013.2255952

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  • Experimental Investigation of Loss Characteristics With AC and DC Offset Transport Current in HTS Double Pancake Coil Reviewed

    J. Ogawa, S. Fukui, T.Oka, T. Sato, M. Shibayama, M. Egawa, A. Sato

    IEEE Transactions on Applied Superconductivity   22 ( 3 )   4705004 - 4705004   2012.6

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    DOI: 10.1109/TASC.2011.2174580

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  • Magnetic Field Distribution of Permanent Magnet Magnetized by Static Magnetic Field Generated by HTS Bulk Magnet Reviewed

    T. Oka, N. Kawasaki, S. Fukui, J. Ogawa, T. Sato, T. Terasawa, Y. Itoh, R. Yabuno

    IEEE Transactions on Applied Superconductivity   22 ( 3 )   9502304 - 9502304   2012.6

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    DOI: 10.1109/TASC.2011.2179510

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  • Numerical Study of Optimization Design of High Temperature Superconducting Field Winding in 20 MW Synchronous Motor for Ship Propulsion Reviewed

    S. Fukui, T. Kawai, M. Takahashi, J. Ogawa, T. Oka, T. Sato, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   22 ( 3 )   5200504 - 5200504   2012.6

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    DOI: 10.1109/TASC.2012.2183331

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  • Measurement and Numerical Analysis of AC Loss in High Temperature Superconducting Coil Reviewed

    S. Fukui, M. Shibayama, J. Ogawa, T. Oka, T. Sato, T. Takao, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   22 ( 3 )   4704904 - 4704904   2012.6

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    DOI: 10.1109/TASC.2011.2175684

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  • Influence of AC Transport Current Balance on AC Loss in a Two Layered Polygonal YBCO Assembled Conductor Reviewed

    J. Ogawa, S. Fukui, T.Oka, T. Sato, A. Tamura, E. Kasuga, KW, Ryu

    IEEE Transactions on Applied Superconductivity   22 ( 3 )   4704804 - 4704804   2012.6

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    DOI: 10.1109/TASC.2011.2177792

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  • Magnetizing of permanent magnets using HTS bulk magnets Reviewed

    T. Oka, T. Muraya, N. Kawasaki, S. Fukui, J. Ogawa, T. Sato, T. Terasawa

    Cryogenics   52 ( 1 )   27 - 31   2012.1

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    DOI: 10.1016/j.cryogenics.2011.10.005

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  • Magnetizing technique for permanent magnets by intense static fields generated by HTS bulk magnets: Numerical Analysis Reviewed

    N. Kawasaki, T. Oka, S. Fukui, J. Ogawa, T. Sato, T. Terasawa, Y. Itoh

    ADVANCES IN SUPERCONDUCTIVITY XXIV   27   188 - 191   2012

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    A demagnetized Nd-Fe-B permanent magnet was scanned in the strong magnetic field space just above the magnetic pole containing a HTS bulk magnet which generates the magnetic field 3.4 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. The finite element method was carried out for the static field magnetization of a permanent magnet using a HTS bulk magnet. Previously, our research group experimentally demonstrated the possibility of full magnetization of rare earth permanent magnets with high-performance magnetic properties with use of the static field of HTS bulk magnets. In the present study, however, we succeeded for the first time in visualizing the behavior of the magnetizing field of the bulk magnet during the magnetization process and the shape of the magnetic field inside the body being magnetized. By applying this kind of numerical analysis to the magnetization for planned motor rotors which incorporate rare-earth permanent magnets, we hope to study the fully magnetized regions for the new magnetizing method using bulk magnets and to give motor designing a high degree of freedom. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of ISS Program Committee

    DOI: 10.1016/j.phpro.2012.03.442

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  • Magnetic separation technique for groundwater by five HTS melt-processed bulk magnets arranged in a line Reviewed

    T. Oka, H. Seki, T. Kimura, D. Mimura, S. Fukui, J. Ogawa, T. sato, M. Ooizumi, H. Fujishiro, H. Hayashi

    Physica C   471 ( 21-22 )   1506 - 1510   2011.11

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    DOI: 10.1016/j.physc.2011.05.226

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  • Mechanical loss and bobbin materials in AC superconducting coil under AC magnetic field Reviewed

    T. Takao, T. Masuda, K. Nishimura, T. Takagi, T. Goto, S. Fukui, A. Yamanaka

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   2420 - 2423   2011.6

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    We made small superconducting coils and measured the total AC loss under the AC and DC external magnetic fields. The coil winding conditions are that 1, 5, and 10 N of the winding tensions and bobbin materials are glass fiber reinforced plastic (GFRP) and Dyneema fiber reinforced plastic (DFRP). The GFRP and the DFRP have thermal strain properties of contraction and expansion respectively with cooldown to cryogenic temperature. Mechanical losses were estimated from the measured data. According to the estimated mechanical losses, the loss of the coil whose bobbin material is the DFRP was small because the DFRP bobbin expanded and hence the winding was tightly fixed. Approximate 10 to 13% of the AC loss can be reduced by only changing the bobbin material from the GFRP to the DFRP. © 2010 IEEE.

    DOI: 10.1109/TASC.2010.2091240

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  • Study of 10MW-class wind turbine synchronous generators with HTS field windings Reviewed

    S. Fukui, J. Ogawa, T. Sato, O. Tsukamoto, N. Kashima, S. Nagaya

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   1151 - 1154   2011.6

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    DOI: 10.1109/TASC.2010.2090115

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  • Development and test of model apparatus utilizing HTS magnetic levitation of non-contact spinning clean-up processors of photo mask production Reviewed

    K. Saito, S. Fukui, J. Ogawa, T. Oka, T. Sato, S. Sorimachi, S. Miyazaki

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   2241 - 2244   2011.6

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    DOI: 10.1109/TASC.2010.2081655

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  • AC loss measurement of a short HTS cable with shield by electrical method Reviewed

    Z. Li, K. Ryu, S. Fukui, S. D. Hwang, G. Cha

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   1005 - 1008   2011.6

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    In order to electrically investigate the AC losses of the conductor and the shield in an actual HTS cable with shield, we attached two voltage-leads to the conductor and shield of a short cable which is the same as the Korea Electric Power Corporation (KEPCO) HTS cable under the field test, and examined it. The result shows that the polarities of the loss voltages measured from both voltage-leads are opposite. The ratio (1.6) between the losses for different transport periods measured from the conductor-lead is quite large. It is considered from these results that the conductor loss is the sum of the losses measured from the conductor-lead and shield-lead. And this conductor loss corresponds well with the numerical result too. Moreover, the total loss of the short cable measured from the proposed electrical method at 77 K was compared with that of the KEPCO cable by calorimetry at 66.6 K through our numerical model. The difference between the measured losses and numerical ones is almost the same. This means that the shield loss is measured from the shield-lead, and the conductor loss from both voltage-leads. © 2010 IEEE.

    DOI: 10.1109/TASC.2010.2084064

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  • Experimental evaluation of the effect on AC loss of a polygoanl arrangement in YBCO assembled conductor Reviewed

    J. Ogawa, S. Fukui, T. Oka, T. Sato, T. Ito, J. Sugisawa, A. Tamura

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   3285 - 3288   2011.6

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    DOI: 10.1109/TASC.2010.2080659

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  • Influence of DC offset transport current on AC loss characteristic in HTS tapes Reviewed

    J. Ogawa, S. Fukui, T.Oka, T. Sato, H. Kojima, M. Shibayama, M. Egawa

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   3325 - 3328   2011.6

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    DOI: 10.1109/TASC.2010.2088099

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  • Performance of trapped magnetic field in superconducting bulk magnets activated by pulsed field magnetization Reviewed

    T. Oka, H. Seki, J. Ogawa, S. Fukui, T. Sato, K. Yokoyama

    IEEE Transactions on Applied Superconductivity   21 ( 3 )   3356 - 3359   2011.6

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    DOI: 10.1109/TASC.2010.2091236

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  • Magnetic separation technique for environmental water purification by strong magnetic field generator loading HTS bulk magnets Reviewed

    T. Oka, Tanaka, T. Kimura, D. Miura, S. Fukui, J. Ogawa, T. Sato, M. Ooizumi, K. Yokoyama, M. Yamaguchi

    Physica C   470 ( 20 )   1799 - 1803   2010.11

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    DOI: 10.1016/j.physc.2010.05.210

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  • Numerical study on AC loss reduction of multi-pole HTS coil by optimal design of winding cross section of element coil Reviewed

    S. Fukui, M. Takahashi, J. Ogawa, T. Oka, T. Sato, M. Yamaguchi, T. Takao

    IEEE Transactions on Applied Superconductivity   20 ( 3 )   2150 - 2153   2010.6

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    DOI: 10.1109/TASC.2010.2044161

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  • Research and development of non-Contact spin processor for clean process in semiconductor-related-production system by applying HTS magnetic levitaion Reviewed

    S. Fukui, K. Kazama, S. Sekiya, J. Ogawa, T. Oka, T. Sato, S. Sorimachi, K. Saito, S. Miyazaki

    IEEE Transactions on Applied Superconductivity   20 ( 3 )   977 - 980   2010.6

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    DOI: 10.1109/TASC.2010.2041766

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  • Influence of transport current distribution on AC transport current loss measurement in an assembled conductor Reviewed

    J. Ogawa, S. Fukui, T. Oka, T. Sato, K. Shinkai, T. Koyama, T. Ito

    IEEE Transactions on Applied Superconductivity   20 ( 3 )   1296 - 1299   2010.6

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    DOI: 10.1109/TASC.2010.2041641

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  • Reduction of mechanical losses due to frictional heat in Bi-2223 tapes using structural materials of various thermal expansion properties Reviewed

    Tomoaki Takao, Tomoaki Masuda, Ryo Sakabe, Kohei Nishimura, Takayuki Goto, Satoshi Fukui, Atsuhiko Yamanaka, Arata Nishimura

    IEEE Transactions on Applied Superconductivity   20 ( 3 )   2115 - 2118   2010.6

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    We measured mechanical loss in an AC magnetic field for a short Bi-2223 superconducting tape. Experimental results indicated that mechanical loss decreased as tension applied to the sample tape increased. Furthermore, when a sample holder with a negative coefficient of thermal expansion was used, mechanical loss reduced. The origin of mechanical loss was confirmed to be the vibration of the sample tape. The expansion holder was the most effective means to reduce the vibration. © 2006 IEEE.

    DOI: 10.1109/TASC.2010.2041338

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  • Numerical analysis of relation between AC loss characteristics and geometrical parameters of multi-layer polygonal conductor assembled by HTS coated conductor Reviewed

    S. Fukui, N. Suzuki, J. Ogawa, T. Oka, T. Sato, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   20 ( 3 )   2138 - 2141   2010.6

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    DOI: 10.1109/TASC.2010.2043661

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  • Waste water purification by magnetic separation technique using HTS bulk magnet system Reviewed

    T. Oka, H. Kanayama, K. Tanaka, S. Fukui, J. Ogawa, T. Sato, M. Ooizumi, T. Terasawa, Y. Itoh, R. Yabuno

    Physica C   469 ( 15-20 )   1849 - 1852   2009.10

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    DOI: 10.1016/j.physc.2009.05.123

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  • Effects of Magnetic Field and Temperature on the Tritium Separation Factor under the SPE Electrolysis["jointly worked"] Reviewed

    Yosuke TAKAHASHI, Yoshifumi SEKIYA, Hiroshi IMAIZUMI, Masaaki SAITO, Satoshi FUKUI, Naoki KANO

    58 ( 7 )   469 - 475   2009.7

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    DOI: 10.3769/radioisotopes.58.469

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  • Numerical Analysis of AC Loss Characteristics of Multi-Layer HTS Cable Assembled by Coated Conductors Reviewed

    S. Fukui, J. Ogawa, N. Suzuki, T. Oka, T. Sato, O. Tsukamoto, T. Takao

    IEEE Transactions on Applied Superconductivity   19 ( 3 )   1714 - 1717   2009.6

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    DOI: 10.1109/TASC.2009.2018050

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  • Influence of thermal cycles on critical current and mechanical loss in superconducting coil having negative thermal expansion bobbin Reviewed

    Tomoaki Takao, Yu Nakajima, Yu Yamada, Kozo Yamamoto, Heisuke Kobayashi, Takayuki Goto, Satoshi Fukui, Atsuhiko Yamanaka

    IEEE Transactions on Applied Superconductivity   19 ( 3 )   2999 - 3002   2009.6

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    We have studied the vibration of superconducting windings during AC excitation of coils. Our previous study revealed that mechanical loss due to the vibration of a coil that had an expansion bobbin during cool-down was smaller than that of a coil having a contraction bobbin. However, critical currents of the coil with the expansion bobbin decreased as the number of thermal cycles increased between room and cryogenic temperatures. Hence, excessive expansion of the bobbins causes degradation of coil performance. In this study, we fabricated superconducting coils whose bobbins expanded a little, and measured the mechanical losses of those coils. We present here the expansion properties of the bobbins, test results of the critical currents and mechanical losses, and the dependence of the thermal cycles on those results. © 2009 IEEE.

    DOI: 10.1109/TASC.2009.2019242

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  • Accuracy of AC Transport Current Loss in HTS Tape Measurements Using a Pick-Up Loop Reviewed

    J. Ogawa, S. Fukui, T. Oka, T. Sato, A. Maruko, H. Tanaka

    IEEE Transactions on Applied Superconductivity   19 ( 3 )   2391 - 2394   2009.6

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    DOI: 10.1109/TASC.2009.2019546

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  • Study of flow fractionation characteristics of magnetic chromatography utilizing high-temperature superconducting bulk magnet Reviewed

    S. Fukui, Y. Shoji, J. Ogawa, T. Oka, M. Yamaguchi, T. Sato, M. Ooizumi, H. Imaizumi, T. Ohara

    SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS   10 ( 1 )   14610 - 14610   2009

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    DOI: 10.1088/1468-6996/10/1/014610

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  • Application of HTS bulk magnet system to the magnetic separation techniques for water purification Reviewed

    T. Oka, H. Kanayama, S. Fukui, J. Ogawa, T. Sato, M. Ooizumi, T. Terasawa, Y. Itoh, R. Yabuno

    Physica C   469 ( 15-21 )   2128 - 2132   2008.9

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    DOI: 10.1016/j.physc.2008.05.234

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  • Study on the performance improvement of the high temperature superconducting coil with several separated coils at the edges Reviewed

    S. Ishiguri, T. Oka, S. Fukui, J. Ogawa, T. Sato

    Physica C   468 ( 15-20 )   2152 - 2155   2008.9

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    DOI: 10.1016/j.physc.2008.05.206

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  • Study on performance improvements of a high-temperature superconducting coil with a lattice-shape cross section Reviewed

    S. Ishiguri, T. Oka, S. Fukui, J. Ogawa, T. Sato

    Physica C: Superconductivity and its Applications   468 ( 14 )   1028 - 1031   2008.7

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    For designing inexpensive high-temperature superconducting (HTS) coils, it is essential to obtain large magnetic fields and stored energy with shorter lengths of HTS tape. To improve the performance of a coil, it is necessary to improve its transport-current performance. The critical current and n-value of an HTS tape were measured at various magnetic field magnitudes and angles at 77 K. The HTS tape employed in the coil was Bi-2223/Ag tape. From this measured data, fitting equations of the critical current and n-values were obtained. With these fitting equations, coil critical currents were analyzed according to our analytical model. The analysis showed that relatively large electric fields are generated at coil edges, inhibiting improvement of the transport-current performance of the coil. To solve this problem, we propose an HTS coil, which is produced by cutting and displacing the central portion of the rectangular cross section. By this rearrangement, the magnetic field distribution changes, resulting in an improvement in the coil critical current. We calculated performances of the proposed coil by varying the magnitude of displaced coils while maintaining a constant total HTS tape length. We found that there is an optimum cross section shape of the proposed coil, which provides improvements in the stored energy and the central magnetic field. In particular, the stored energy improves by approximately 43% compared with a rectangular cross section coil employing the same HTS tape length. © 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2008.05.148

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  • Numerical analysis of AC transport current loss measurements using a pick-up loop Reviewed

    J. Ogawa, S. Fukui, T. Oka, M. Yamaguchi, T. Sato, T. Hamada, H. Tanaka

    IEEE Transactions on Applied Superconductivity   18 ( 2 )   1358 - 1361   2008.6

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    DOI: 10.1109/TASC.2008.920817

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  • AC transport current loss characteristics of HTS assembled conductors arranged edge-to-edge or face-to-face Reviewed

    J. Ogawa, S. Fukui, T. Oka, M. Yamaguchi, T. Sato, S. Kume, K. Shinkai, S. Sato

    IEEE Transactions on Applied Superconductivity   18 ( 2 )   1353 - 1357   2008.6

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    DOI: 10.1109/TASC.2008.920696

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  • Numerical simulation of flow fractionation characteristics of magnetic chromatography using an HTS bulk magnet Reviewed

    S. Fukui, Y. Shoji, R. Abe, J. Ogawa, M. Yamaguchi, T. Sato, H. Imaizumi, T. Ohara

    IEEE Transactions on Applied Superconductivity   18 ( 2 )   828 - 831   2008.6

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    DOI: 10.1109/TASC.2008.921248

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  • Effect of thermal cycles on critical current and AC loss for superconducting coils having positive or negative thermal expansion bobbin Reviewed

    T. Takao, K. Yamamoto, Y. Yamada, Y. Nakajima, K. Nakamura, M. Arikawa, S. Fukui, A. Nishimura, A. Yamanaka

    IEEE Transactions on Applied Superconductivity   18 ( 2 )   1378 - 1381   2008.6

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    We investigated the effect of thermal cycles between room and liquid-nitrogen temperatures on the critical current (Ic) and AC loss of two superconducting coils: one with a bobbin that expands during cooling from room temperature to cryogenic temperature and one with a bobbin that contracts during the cooling. After 100 cycles, neither bobbin suffered degradation. The Ic of the contraction-bobbin coil did not decrease, and that of the expansion-bobbin coil decreased due to the repeated thermal strain. The expansion coil's AC loss was significantly smaller than the contraction coil's loss at the first cycle
    however, it increased with the thermal cycles and eventually surpassed the contraction coil's loss because the Ic of the expansion coil decreased due to the thermal fatigue. These results indicate that a moderate expansion in the size of the bobbin effectively decreases AC loss and that excessive expansion reduces the Ic and increases the AC loss. © 2008 IEEE.

    DOI: 10.1109/TASC.2008.920586

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  • Study on optimal design of high temperature superconducting coil based on AC loss minimization Reviewed

    S. Fukui, K. Ohsugi, T. Nishijyo, J. Ogawa, T. Oka, M. Yamaguchi, T. Sato, M. Furuse, T. Takao, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   18 ( 2 )   1366 - 1369   2008.6

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    DOI: 10.1109/TASC.2008.920823

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  • Compactly composed strong magnetic field generators with cryo-cooled high temperature bulk superconductors as quasi-permanent magnets Reviewed

    T. Oka, Y. Hirose, H. Kanayama, H. Kikuchi, J. Ogawa, S. Fukui, T. Sato, M. Yamaguchi

    Journal of Physics: Conference Series   97 ( 1 )   2008.2

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    The authors have constructed various types of strong magnetic field generators using superconducting bulk magnets in conjunction with compact refrigerators. The magnetic field in the open space outside the vacuum chamber that contains a bulk magnet has been estimated as over 3 T when activated by the static fields of a 5 T superconducting solenoid magnet. The authors have tried to extend the variation of such strong field generators which are promised to develop in the future. In the study, a novel and compact bulk magnet system with use of a compact pulse tube cryocooler has recorded the maximum trapped field of 2.78 T on the magnetic pole surface. The characteristic feature of superconducting bulk magnet is defined as a compact and strong magnetic field generator. This implies that various kinds of equipments must be successively proposed even in the very early stage of industrialization of strong magnetic field generators. © 2008 IOP Publishing Ltd.

    DOI: 10.1088/1742-6596/97/1/012102

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  • Performances of compact magnetic field generators using cryo-cooled high temperature bulk superconductors as auasi-permanent magnets Reviewed

    T. Oka, Y. Hirose, H. Kanayama, H. Kikuchi, S. Fukui, J. Ogawa, T. Sato, M. Yamaguchi

    Superconductor Science and Technology   20   1233 - 1238   2007.12

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    DOI: 10.1088/0953-2048/20/12/025

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  • Study on application of magnetic levitation utilizing HTS bulks to spin processors for photo mask production Reviewed

    S. Fukui, R. Sato, J. Ogawa, T. Oka, M. Yamaguchi, T. Sato, S. Miyazaki, T. Sasahara, T. Tamaki, S. Nishiwaki, Y. Yuki

    Physica C   463-465   1289 - 1292   2007.10

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    DOI: 10.1016/j.physc.2007.04.300

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  • Evaluation of the measurement of AC transport current loss in assembled HTS tapes using a pick-up loop Reviewed

    J. Ogawa, S. Fukui, T. Oka, M. Yamaguchi, T. Sato, K. Yamaya, T. Hamada, H. Tanaka

    Physica C   463-465   1159 - 1162   2007.10

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    DOI: 10.1016/j.physc.2007.02.022

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  • Study on optimization design of superconducting magnet for magnetic force assisted drug delivery system Reviewed

    S. Fukui, R. Abe, J. Ogawa, T. Oka, M. Yamaguchi, T. Sato, H. Imaizumi

    Physica C   463-465   1315 - 1318   2007.10

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    DOI: 10.1016/j.physc.2007.04.306

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  • Numerical Study on AC Transport Current Loss Measurement of HTS Assembled Conductor by Pick-up Loop without Electrical Contacts Reviewed

    S. Fukui, S. Watanabe, J. Ogawa, M. Yamaguchi, T. Sato, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   17   1704 - 1707   2007.6

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    DOI: 10.1109/TASC.2007.897249

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  • Study on the Effect of Fault Current Limiter in Power System With Dispersed Generators Reviewed

    T. Sato, M. Yamaguchi, T. Terashima, S. Fukui, J. Ogawa, H. Shimizu, T. Sato

    IEEE Transactions on Applied Superconductivity   17   2331 - 2334   2007.6

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    DOI: 10.1109/TASC.2007.899884

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  • A Study on the Performance Improvement of an HTS Coil by the Outer Corner Modification Reviewed

    S. Ishiguri, M. Yamaguchi, S. Fukui, J. Ogawa, T. Sato

    IEEE Transactions on Applied Superconductivity   17   2386 - 2389   2007.6

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    DOI: 10.1109/TASC.2007.898426

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  • Influence of high frequency AC magnetic field on trapped magnetic field in HTS bulk Reviewed

    J. Ogawa, S. Fukui, T. Oka, M. Yamaguchi, T. Sato, M. Takada, R. Sato, M. Tomita

    IEEE Transactions on Applied Superconductivity   17   3024 - 3027   2007.6

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    DOI: 10.1109/TASC.2007.899000

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  • Numerical Study on AC Loss Minimization of Multi-Layer Tri-Axial HTS Cable for 3-Phase AC Power Transmission Reviewed

    S. Fukui, T. Noguchi, J. Ogawa, M. Yamaguchi, T. Sato, O. Tsukamoto, T. Takao

    IEEE Transactions on Applied Superconductivity   17   1700 - 1703   2007.6

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    DOI: 10.1109/TASC.2007.897243

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  • A Study on High Temperature Superconducting Coil of Different Coil Arrangements Reviewed

    M. Watanabe, S. Ishiguri, R. Maruyama, M. Yamaguchi, S. Fukui, J. Ogawa, T. Sato

    IEEE Transactions on Applied Superconductivity   17   2002 - 2005   2007.6

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    DOI: 10.1109/TASC.2007.898425

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  • Influence of mechanical vibration and losses in Bi-2223 coils on thermal expansion properties of bobbin materials

    Tomoaki Takao, Yuta Furumura, Minoru Arikawa, Kozo Yamamoto, Yu Yamada, Takayuki Goto, Arata Nishimura, Satoshi Fukui, Atsuhiko Yamanaka

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   17 ( 2 )   2414 - 2417   2007.6

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    We fabricated small superconducting coils whose bobbins were made of a Dyneema fiber reinforced plastic (DFRP), a Dyneema and glass fiber reinforced plastic (DGFRP), and a glass fiber reinforced plastic (GFRP). Because Dyneema fibers in the FRP expand, we are able to control thermal expansion/contraction property in a circumferential direction of the DFRP and the DGFRP pipes during a cooling process from room temperature to low temperature. We fabricated two kinds of the DFRP and the DGFRP coils whose properties were expansion and contraction. The GFRP has always a characteristic of contraction during cool-down. We measured a mechanical loss that occurred in the coil during AC excitation of those coils. The mechanical losses decreased with increasing winding tension of the conductor in the coils according to the experimental data. And the mechanical loss of the coils whose bobbins had characteristic of expansion was considerably smaller than that of contraction. It was experimentally shown that the bobbins with expansion property during the cooling down were effective to decrease the mechanical loss of the AC coils.

    DOI: 10.1109/TASC.2007.899879

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  • Study on cross section of high temperature superconducting coil Reviewed

    S. Ishiguri, M. Yamaguchi, S. Fukui, J. Ogawa, T. Sato

    Cryogenics   47   31 - 35   2007

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    DOI: 10.1016/j.cryogenics.2006.09.003

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  • Comparison between experimental and numerical analysis of AC transport current loss measurement in YBCO tapes in an assembled conductor Reviewed

    J. Ogawa, S. Fukui, M. Yamaguchi, T. Sato, O. Tsukamoto, S. Nakamura

    Physica C   445-448   1083 - 1087   2006.10

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    DOI: 10.1016/j.physc.2006.05.038

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  • Magnetization Loss in a Striated YBCO Coated Conductor Considering the Intrinsic Critical Current Distribution Reviewed

    J. Ogawa, S. Fukui, M. Yamaguchi, T. Sato, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   16 ( 2 )   111 - 114   2006.6

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    DOI: 10.1109/TASC.2005.869673

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  • Numerical study on magnetic chromatography using quadrupole magnetic field Reviewed

    M. Takahashi, S. Fukui, Y. Takahashi, R. Abe, J. Ogawa, M. Yamaguchi, T. Sato, H. Imaizumi, T. Ohara

    IEEE Transactions on Applied Superconductivity   16 ( 2 )   1116 - 1119   2006.6

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    DOI: 10.1109/TASC.2006.871336

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  • Numerical study on AC loss characteristics of HTS coils with various cross sections and methods of AC loss reduction Reviewed

    S. Fukui, T. Nishijyo, S. Abe, J. Ogawa, M. Yamaguchi, T. Sato, M. Furuse, H. Tanaka, K. Arai, M. Umeda, T. Takao

    IEEE Transactions on Applied Superconductivity   16 ( 2 )   139 - 142   2006.6

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    DOI: 10.1109/TASC.2006.870018

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  • Numerical Analysis of AC Loss Characteristics of Cable Conductor Assembled by HTS Tapes in Polygonal Arrangement Reviewed

    S. Fukui, R. Kojima, J. Ogawa, M. Yamaguchi, T. Sato, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   16 ( 2 )   143 - 146   2006.6

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    DOI: 10.1109/TASC.2006.870818

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  • Dependence of AC loss with a phase difference between transport current and applied magnetic field Reviewed

    J. Ogawa, S. Fukui, M. Yamaguchi, T. Sato, Y. Kobayashi, K. Yamaya, R. Takatsuka

    IEEE Transactions on Applied Superconductivity   16 ( 2 )   115 - 118   2006.6

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    DOI: 10.1109/TASC.2006.871213

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  • Analysis of AC Loss and Current Distribution Characteristics of Multi-Layer Triaxial HTS Cable for 3-Phase AC Power Transmission Reviewed

    S. Fukui, T. Noguchi, J. Ogawa, M. Yamaguchi, T. Sato, O. Tsukamoto

    IEEE Transactions on Applied Superconductivity   16 ( 2 )   135 - 138   2006.6

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    DOI: 10.1109/TASC.2006.870817

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  • Mechanical losses due to frictional heat in Bi-2223 tapes with structural materials of various thermal expansion properties Reviewed

    Tomoaki Takao, Yata Furumura, Takashi Higuchi, Minoru Arikawa, Kozo Yamamoto, Takayuki Goto, Satoshi Fukui, Atsuhiko Yamanaka

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   16 ( 2 )   101 - 104   2006.6

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    We have experimentally studied relation between mechanical losses and thermal expansion properties in superconducting coils. For the experiments, three kinds of structural materials (GFRP, DGFR-P, and ZFRP) were used. A glass fiber reinforced plastic (GFRP) contracts with decreasing temperature; on the contrary, a Dyneema and grass fiber reinforced plastic (DGFRP) and a Zylon fiber reinforced plastic (ZFRP) expand with the decrease of temperature. We used sample holders made of those plastics and measured AC current losses of a Bi-2223 tape in liquid nitrogen. Even if the magnetic field applied to the. tape and an AC transport current of the tape were same, the loss depended on the sample holder materials. When the sample holder is the GFRP, the loss was largest in the three kinds of plastics, and in case of the ZFRP, the loss was smallest. The ZFRP has the largest expansion property of the three materials, that is, the loss decreased with expansion of the sample holder's materials.

    DOI: 10.1109/TASC.2005.869690

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  • Analysis of AC Loss Characteristics of HTS Coils with Various Cross Sections Reviewed

    S. Abe, T. Nishijyo, S. Fukui, J.Ogawa, M. Yamaguchi, T. Sato, M. Furuse, H. Tanaka, K. Arai, M. Umeda, T. Takao

    Physica C   426-431 ( 2 )   1316 - 1321   2005.10

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    DOI: 10.1016/j.physc.2005.03.052

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  • Study on the optimum design of a high temperature superconducting coil Reviewed

    S. Ishiguri, M. Yamaguchi, S. Fukui, J. Ogawa, T. Sato

    Physica C   426-431 ( 2 )   1390 - 1396   2005.10

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    DOI: 10.1016/j.physc.2005.02.108

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  • Analysis of AC Loss and Current Distribution in Multi-Layer Tri-Axial Three-Phase HTS Cable Reviewed

    S. Fukui, T. Noguchi, J. Ogawa, M. Yamaguchi, T. Sato, O. Tsukamoto

    Physica C   426-431 ( 2 )   1374 - 1379   2005.10

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    DOI: 10.1016/j.physc.2005.03.055

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  • A study on DC hybrid three-phase fault current limiting interrupter for a power distribution system Reviewed

    H. Shao, T. Satoh, M. Yamaguchi, S. Fukui, J. Ogawa, T. Satoh, H. Ishikawa

    Physica C   426-431 ( 2 )   1380 - 1384   2005.10

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    DOI: 10.1016/j.physc.2005.01.070

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  • Analysis of AC Loss Characteristics of High Temperature Superconducting Coil Reviewed

    S. Fukui, H. Tonsho, M. Toyoda, J. Ogawa, M. Yamaguchi, T. Sato, M. Furuse, H. Tanaka, K. Arai, M. Umeda, T. Takao

    IEEE Transactions on Applied Superconductivity   15 ( 2 )   1566 - 1569   2005.6

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    DOI: 10.1109/TASC.2005.849173

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  • Performance comparison of a DC hybrid type FCLI with other types Reviewed

    H. Shao, M. Yamaguchi, S. Fukui, J. Ogawa, T. Sato, H. Ishikawa

    IEEE Transactions on Applied Superconductivity   15 ( 2 )   2126 - 2129   2005.6

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    DOI: 10.1109/TASC.2005.849469

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  • Numerical evaluation of separation characteristics of open gradient magnetic separation using quadrupole magnetic field Reviewed

    M. Takahashi, T. Umeki, S. Fukui, J. Ogawa, M. Yamaguchi, T. Sato, H. Imaizumi, M. Oizumi, S. Nishijima, T. Watanabe

    IEEE Transactions on Applied Superconductivity   15 ( 2 )   2340 - 2343   2005.6

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    DOI: 10.1109/TASC.2005.849661

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  • Proposal of numerical model for current distribution analysis in high temperature superconducting parallel conductor

    Akira Watabe, Satoshi Fukui, Takao Sato, Mitsugi Yamaguchi

    Physica C: Superconductivity and its Applications   412-414   1139 - 1142   2004.10

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    A numerical model to calculate current density distribution in a parallel conductor assembled by multiple high temperature superconducting tapes was proposed. The numerical calculations on the current distribution in the parallel conductor of three high-temperature superconducting tapes were performed by using the developed model. The numerical results showed that the current density distribution in the parallel conductor were affected by the tape arrangement in the conductor. © 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2004.01.137

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  • Numerical evaluation of AC loss in high temperature superconducting coil Reviewed

    H Tonsho, M Toyoda, S Fukui, M Yamaguchi, T Sato, M Furuse, H Tanaka, K Arai, M Umeda

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   14 ( 2 )   674 - 677   2004.6

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    An approximated method to estimate the electro-magnetic AC loss in high temperature superconducting coil was proposed. We applied this method to estimate the AC loss characteristics of the high temperature superconducting coil made by stacking pancake coils which are wound by Bi2223/Ag tape. The analytical AC losses of the HTS coil were compared with the measured AC losses before and after impregnation by epoxy resin obtained in the previous work by National Institute of Advanced Industrial Science and Technology. The analytically estimated electro-magnetic AC losses in the HTS coil were much smaller than the measured AC loss of the coil. The AC loss characteristics could not be explained by the method proposed in this paper. The main reason of this discrepancy was considered that the measured AC losses in the HTS coil contained large amount of the mechanical AC loss due to the AC vibration of the winding even if the HTS coil was impregnated.

    DOI: 10.1109/TASC.2004.830027

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  • Numerical analysis of AC loss and current distribution characteristics of co-axial multi-layer high temperature superconducting cable Reviewed

    A Watabe, S Fukui, M Yamaguchi, T Sato, T Takao, O Tsukamoto

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   14 ( 2 )   678 - 681   2004.6

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    An numerical model to calculate the inter-layer current distributions and the AC losses in co-axial multi-layer cable conductors was developed. The inter-layer current distributions and the AC losses in 4-layer cables were numerically calculated for various combinations of twist pithes and twist directions of the cables. With the numerical model, the twist pitch combinations to equalize the inter-layer current distribution and to reduce the AC loss were also investigated. The analytical results showed the remarkable dependence of the losses and the current distributions on the twist pitches and the directions of the cables. The optimized cable structures were discussed by the numerical results.

    DOI: 10.1109/TASC.2004.830028

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  • A study on DC hybrid three-phase fault current limiting interrupter Reviewed

    H Shao, M Yamaguchi, S Fukui, T Sato, Y Watanabe

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   14 ( 2 )   800 - 803   2004.6

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    The authors studied a dc hybrid three-phase fault current limiting interrupter composed of a superconducting reactor and an S/N transition element, connected in series each other. This device has the capability of interruption of a limited fault current. In this paper, the experiments on this device with a test model are described and compared with analyses. A proper combination of a reactor coil and an S/N transition element is also discussed for 6.6 kV-2000 A power systems.

    DOI: 10.1109/TASC.2004.830276

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  • Study on a cross section of high temperature superconducting coil Reviewed

    S Ishiguri, M Yamaguchi, S Fukui, T Sato

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   14 ( 2 )   1858 - 1861   2004.6

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    The fitting equations of critical current and n value were derived from measured data of Ag-sheathed Bi-2223 tapes concerning the magnetic fields and flux angles at 77 K. The critical current of a high temperature superconducting coil can be calculated with these equations together with a magnetic field analysis of a coil. Critical current, magnetic field, flux How loss, stored energy, etc. were calculated for HTS coils with various coil aspect ratios along the curve, where Fabry Factor F of 1.97 was kept constant. It was made clear that the central magnetic field per coil volume is maximum at the coil aspect ratio providing the minimum coil volume.

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  • Influence of mechanical losses in AC superconducting coils having composite materials reinforced with dyneema and glass fibers Reviewed

    N Sekine, S Tada, T Higuchi, T Takao, A Yamanaka, S Fukui

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   14 ( 2 )   1161 - 1164   2004.6

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    When a Dyneema fiber reinforced plastic (DFRP) is used as a superconducting coil's bobbin, the decrease of the winding tension during cooling down is prevented. Therefore, it is expected that a mechanical loss generated in AC superconducting coils is reduced. The DFRP has the high Young's modulus to the fiber direction, however the modulus to the perpendicular direction is lower than the modulus of the glass fiber reinforced plastic (GFRP), which is generally used as a structural material in superconducting coils. Therefore, a Dyneema and glass fiber reinforced plastic (DGFRP), which was compounded the Dyneema and the glass fibers, was fabricated for the purpose of the intensification of the DFRP, and total losses of the superconducting coils having some kinds of DGFRP bobbins were measured under AC operation. In loss measurements, the coil whose loss was the smallest was the coil having the strongest winding tension at cryogenic temperature, and the coil whose loss was the largest was the coil having the weakest tension. Moreover, comparing with the results of the loss measurement in the coils fabricated with the DFRP bobbin, the losses of the coils having the DGFRP bobbins were slightly large due to the mixture of the Dyneema and the glass fibers. This paper reports the effect of the reduction of the mechanical losses in the coils having the DGFRP bobbins and the comparison with the coils whose bobbins are the DFRP and the GFRP.

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  • Conceptual design of 100 MVA high temperature superconducting auto-transformers Reviewed

    T Nagasawa, M Yamaguchi, S Fukui

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   13 ( 2 )   2306 - 2309   2003.6

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    This paper describes the conceptual design of 100 MVA high temperature superconducting (HTS) autotransformers as well as coreless ones having the rating of three-phase, 50 Hz, and 132 kV/66 kV. Each one is compared with conventional oil-immersed autotransformers. The HTS autotransformers with core will provide a percent impedance of 11.7% close to the conventional one and require an air gap field of 0.33 T, while the coreless HTS autotransformers require 25.8% and 0.7 T respectively. HTS antotransformers with a core have a 22% smaller window size and 0.3% higher efficiency than conventional ones. The coreless HTS autotransformers need HTS tapes about two times the length required for the HTS autotransformer with a core.

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  • Theoretical and experimental study on AC loss in HTS tape in AC magnetic field carrying AC transport current Reviewed

    H Tonsho, S Fukui, T Sato, M Yamaguchi, S Torii, T Takao, K Ueda

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   13 ( 2 )   2368 - 2371   2003.6

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    AC loss characteristics of. high temperature superconducting tape in external AC magnetic field carrying AC transport current were theoretically and experimentally studied. We measured the AC transport current and magnetization losses in a conventional Bi2223/Ag multifilamentary tape in the external AC magnetic field carrying the AC transport current. The measured AC magnetization loss, AC transport current loss and total AC loss were compared with the numerical results. The measured AC loss characteristics of the tape can not be explained by the critical state model. Numerical calculations on the AC losses in the tape were performed by using our analytical model introducing the electric field and current density relation locally determined in the filamentary region of the tape. The numerical losses by our model reasonably agree with the measured data.

    DOI: 10.1109/TASC.2003.813071

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  • AC loss characteristics of Bi2223 twisted multifilamentary tape in AC longitudinal magnetic field Reviewed

    T Yoshida, S Fukui, M Yamaguchi, T Sato

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   13 ( 2 )   2372 - 2375   2003.6

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    AC loss characteristics of the twisted multifilamentary high temperature superconducting tape,with different twist pitches in external AC longitudinal magnetic field as well as those of the nontwisted tape were experimentally investigated. We measured the AC transport current loss and the AC magnetization loss in the twisted and nontwisted Bi2223 multifilamentary tapes in the external AC longitudinal magnetic field. The measured transport loss and magnetization loss in the twisted tapes were affected, by the amplitude and the direction of the AC longitudinal field. It was also shown that the AC losses in the tapes under the external AC longitudinal field depended on the twist pitch.

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  • Investigation of AC loss characteristics of Bi2223 twisted multifilamentary tape Reviewed

    S. Fukui, M. Ikeda, T. Yoshida, T. Sato, M. Yamaguchi

    IEEE Transactions on Applied Superconductivity   12 ( 1 )   1612 - 1615   2002.3

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    AC loss characteristics of the twisted and not-twisted Bi2223/Ag/AgMg multifilamentary tapes in the longitudinal and transverse AC external magnetic fields were experimentally investigated. The measured AC transport current loss and the AC magnetization loss in the twisted tape were affected by the amplitude and the direction of the longitudinal AC magnetic field. The magnetization loss in the transverse AC magnetic field in the twisted tape was smaller than that in the not-twisted tape. The total AC loss properties were discussed.

    DOI: 10.1109/TASC.2002.1018713

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  • Study on open gradient magnetic separation using multiple magnetic field sources Reviewed

    S. Fukui, H. Nakajima, A. Ozone, M. Hayatsu, M. Yamaguchi, T. Sato, H. Imaizumi, S. Nishijima, T. Watanabe

    IEEE Transactions on Applied Superconductivity   12 ( 1 )   959 - 962   2002.3

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    A new type of open gradient magnetic separator using multiple magnetic field sources was proposed. As an example, a open gradient magnetic separation using quadrupole magnetic field was focused in this paper. Simulation study was performed to investigate the basic separation characteristics of our separation method by analyzing the dynamic behavior of magnetic particles. The simulation results show that the continuous separation of paramagnetic particles of several tens micrometer diameter is enough feasible. We demonstrated the validity of proposed method by an experiment using quadrupole electromagnet.

    DOI: 10.1109/TASC.2002.1018559

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  • Analysis of AC transport characteristic of high Tc multilayer cable Reviewed

    S Fukui, M Yamaguchi, O Tsukamoto, T Takao

    ADVANCES IN CRYOGENIC ENGINEERING, VOLS 48A AND B   614   1183 - 1190   2002

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    Numerical studies on characteristics of electromagnetic behaviors of co-axial multi-layer superconducting cable conductors with superconducting magnetic shields were performed. The inter-layer current distribution and AC loss dependencies on the twist pitches and the diameter of the superconducting layers of the cables were investigated. The numerical results showed that the magnetic field produced by the shielding currents flowing in the superconducting magnetic shield strongly affected the current distribution and the AC losses of the cable. Based on the model, the optimized cable structures for uniform current distribution and to reduce the AC losses were studied. Examples of the optimized structures obtained by our model were presented and compared with those obtained by the conventional electrical circuit model. The differences between the results obtained by our model and those obtained by the circuit model were discussed.

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  • Proposal for Standardization of a Test Method for Critical Current Measurement of Cu/Cu-Ni/Nb-Ti Composite Superconductors. Reviewed

    Yoshio KUBO, Rikuo OGAWA, Tomoaki TAKAO, Satoshi FUKUI, Osami TSUKAMOTO, Kozo OSAMURA

    TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)   37 ( 12 )   765 - 774   2002

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    DOI: 10.2221/jcsj.37.765

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  • Grease impregnation effect in measurement of critical current for NbTi superconductors Reviewed

    Naoki Sekine, Tomoaki Takao, Yushi Kojo, Mokichi Neya, Yoshio Kubo, Rikuo Ogawa, Satoshi Fukui, Osami Tsukamoto

    IEEE Transactions on Applied Superconductivity   12 ( 1 )   1799 - 1802   2002

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    We have studied a measuring method of a critical current (Ic) for NbTi superconducting wires having a Cu matrix and Cu/CuNi matrices. To prevent the wires from prematurely quenching before reaching their Ic, we tried grease impregnations to sample coils. When the NbTi/Cu wire was used for the coil, silicon grease impregnation was enough to fix the wire and to measure the Ic of the wire. In case that we used the NbTi/Cu/CuNi wire when measuring the Ic, restraint of wire motion by the silicon grease impregnation was insufficient and the sample coil easily quenched before reaching the Ic. Accordingly, the Apiezon® (type: M) grease was used for an impregnation material, and we found the Apiezon grease was effective in fixing the NbTi/Cu/CuNi wire.

    DOI: 10.1109/TASC.2002.1018589

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  • Three-phase fault current limiter with one dc S/N transition element Reviewed

    T Satoh, M Yamaguchi, S Fukui, K Morikoshi, K Kaiho, T Matsumura, H Shimizu, N Murayama

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   11 ( 1 )   2398 - 2401   2001.3

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    We developed a de S/N transition type three-phase fault current limiter, the primary element of which, is made of the superconducting bulk material, Bi-2223. This element is connected to secondary windings of transformers, through a modified half control bridge. This unique, single element device simultaneously limits and interrupts fault current, in three-phase power systems, This paper describes the results of tests, using a small scale model and simulation results.

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  • Single DC reactor type fault current limiter for 6.6 kV power system Reviewed

    T Nomura, M Yamaguchi, S Fukui, K Yokoyama, T Satoh, K Usui

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   11 ( 1 )   2090 - 2093   2001.3

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    We propose a single de reactor type fault current limiter, This fault current limiter is for a three-phase power system, employing only one superconducting coil that is connected with the secondary windings of transformers through a diode-bridge. In this composition, a de reactor type fault, current limiter using a high temperature superconducting coil takes advantage of coil inductance and does not require a superconducting coil normal transition. This paper presents the most suitable case of a single de reactor type fault current limiter for a 6.6 kV power system and compares it with a three de reactors type fault current limiter.

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  • A single dc reactor type fault current limiting interrupter for three-phase power system Reviewed

    K Usui, T Nomura, T Satoh, M Yamaguchi, S Fukui, K Yokoyama, T Nagasawa

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   11 ( 1 )   2126 - 2129   2001.3

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    We propose a single de reactor type fault current limiting interrupter (FCLI) for a three-phase power system, The device uses a single high temperature superconducting (HTS) coil that operates in conjunction with a modified half control bridge composed of thyristors and diodes connected to a transformer's secondary windings. One variety is an automatic interrupter, which automatically blocks fault current through the application of de bias current to the bridge. Another is a gate interrupter, which does the same thing by blocking the thyristor's gate pulses. We will examine the results of various simulations on a new device that both limits and interrupts fault current in a three-phase power system.

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  • Analysis and measurement of AC transport current loss in BSCCO tape in external magnetic field Reviewed

    S Fukui, M Ikeda, T Sano, H Sango, M Yamaguchi, T Takao

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   11 ( 1 )   2212 - 2215   2001.3

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    A numerical model to calculate current distribution and AC loss in a high temperature superconducting tape carrying Ae transport current exposed to external magnetic field was developed. The model considers the electric field and current density relation and the shape of wire, We measured the AC transport current losses in a conventional Bi2223/Ag multifilamentary tape in the DC external magnetic field and the results were compared with the numerically calculated AC losses. The measured AC transport current losses increase as the DC external field increases. It is also shown that the measured losses per cycle decrease with increasing frequency, These characteristics can not he explained by the critical state model. The numerical losses by our model reasonably agree with the measured data. The transport loss characteristics under the DC field and their dependence on the frequency are explained by the numerically calculated current distribution in the wire.

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  • Application of single dc reactor type fault current limiter as a power source Reviewed

    K. Yokoyama, T. Sato, T. Nomura, S. Fukui, M. Yamaguchi

    IEEE Transactions on Applied Superconductivity   11 ( 1 )   2106 - 2109   2001.3

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    This paper presents an application of single dc reactor type fault current limiter (FCL) with a gate turn-off (GTO) thyristor bridge as an emergency power source. A dc reactor type FCL stores electrical energy in a superconducting coil at a steady state. When a power transmission stops due to line faults, the FCL supplies stored energy to the load. This conception can be realized by operating the GTO thyristor bridge as an inverter. On the other hand, the function of fault current limitation is possible by keeping all GTO thyristors turned-on. The proposed FCL is numerically tested in a three-phase distribution system.

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  • Study of single dc device type FCL for three-phase power system Reviewed

    T Nomura, M Yamaguchi, S Fukui, K Yokoyama

    CRYOGENICS   41 ( 2 )   125 - 130   2001.2

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    Various types of fault current limiters (FCLs) that use superconducting element are proposed and are under development, but there are many technical issues: their cost, fault current limiting ability, etc., so at present are far from commercialization. The purpose of this work is to study single de device type FCL for three-phase power system. The device uses single high temperature superconducting coil that is operated in the diode bridge connected to transformer's secondary windings. The bias power supply is required in the bridge for a rectification type limiter to avoid the distortion of load currents. This bias power supply requires the ability to supply at least the load currents in the steady state in the power system. Also the ability that many times of rated line currents can flow in the bias power supply at the time of a fault is required. In this paper, we study technical items that are demanded on this bias power supply and provide the optimal constitution of simple de device type FCL for three-phase power system. (C) 2001 Published by Elsevier Science Ltd.

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  • AC Transport Current Loss Characteristics of Twisted Multifilament Bi/Ag Sheathed Tape Subject to AC Longitudinal Magnetic field Reviewed

    J. Ogawa, O. Tsukamoto, M. Ciszek, N. Amemiya, S.Fukui

    Advances in Cryogenic Engineering (Materials)   48 ( B )   740 - 747   2001

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  • Investigation of AC loss and current distribution in co-axially assembled cable conductor of multiple HTS tapes Reviewed

    S Fukui, T Hirasawa, K Satoh, M Yamaguchi, T Satoh, T Takao

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   10 ( 1 )   1146 - 1149   2000.3

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    Numerical studies on characteristics of the inter-layer current distribution and the AC losses in co-axial multi-layer cable conductors with superconducting magnetic shields were performed by using the model developed by our previous study. The inter-layer current distribution and AC loss dependencies on the twist pitches, the diameter and the numbers of the superconducting layers of the cables were investigated. The analytical results showed that the magnetic field produced oy the shielding currents strongly affected the current distribution and the AC losses of the cable. Based on the model, the optimized cable structures to achieve the uniform current distribution and to reduce the AC losses were studied. Examples of the optimized structures obtained by our model were presented and compared with those obtained by the conventional electric circuit model.

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  • Measuring method of critical current for NbTi superconductors with Cu and CuNi matrices Reviewed

    T Takao, T Suzuki, N Sekine, S Fukui, O Tsukamoto, Y Kubo, R Ogawa

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   10 ( 1 )   1255 - 1258   2000.3

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    Quench characteristics of NbTi superconducting wires with Cu and CuNi matrices have been experimentally studied to standardize a measuring method of critical current (Ic) for the wires. In the previous work, the superconducting wires frequently quenched caused by abrupt wire motions before reaching their Ic. Hence, we tried to measure Ic under various fixing conditions of the wires (1, 5, and 10 N of winding tensions to the wires, dry windings and impregnation by two types of grease (silicone and Apiezon(R)), non-metallic and metallic sample mandrels). The experimental results showed that 10 N of the winding tension was best in the three tensions, and Apiezon grease impregnation was effective. However, the wire currents in the above conditions did not reach their Ic at low magnetic fields. When the wires were fixed by soldier on the metallic mandrels, the wire currents always reached their Ic with no premature quenches due to the wire motions. We obtained a prospect to standardize the measuring method of Ic for the three-component superconducting wires.

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  • Origins of errors in AC transport current loss measurements of HTS tapes and methods to suppress errors Reviewed

    O. Tsukamoto, J. Ogawa, M. Ciszek, D. Miyagi, I. Okazaki, Y. Niidome, S. Fukui

    IEEE Transactions on Applied Superconductivity   11 ( 1 )   2208 - 2211   2000

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    DOI: 10.1109/77.920297

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  • Recent technical trends of superconducting magnets in Japan, Part I: magnet data base and recent progress in magnet winding current density Reviewed

    O. Tsukamoto, S. Torii, T. Takao, N. Amemiya, S. Fukui, T. Hoshino, A. Ishiyama, A. Ninomiya, H. Yamaguchi, T. Satow, members of committee on, u, rconducting, apparatuses, d, characteristics of superconductors

    IEEE Transactions on Applied Superconductivity   9 ( 2 )   547 - 552   1999.6

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    DOI: 10.1109/77.783355

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  • Recent technical trends of superconducting magnets in Japan, Part II: stability and quench characteristics Reviewed

    T. Takao, S. Torii, N. Amemiya, S. Fukui, T. Hoshino, A. Ishiyama, A. Ninomiya, H. Yamaguchi, T. Satow, O. Tsukamoto, members of committee on, u, rconducting, apparatuses, a, d, characteristics of superconductors

    IEEE Transactions on Applied Superconductivity   9 ( 2 )   600 - 603   1999.6

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    DOI: 10.1109/77.783367

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  • AC losses of HTS coils carrying transport current Reviewed

    T Honjo, T Hasegawa, K Kaiho, H Yamaguchi, K Arai, M Yamaguchi, S Fukui, K Kato, K Itagaki

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   9 ( 2 )   829 - 832   1999.6

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    In the paper we report the experimental results for ac losses in HTS coil carrying ac transport current. The tests of ac losses mere performed by the electrical method at 77 K and 4.2 K. The HTS tape consists of 55 multi-filamentary silver-sheathed BSCCO 2223 tape without twisting. The sample coil was made by the React and Wind method using insulated tape conductor. The coil has the inner diameter of 46 mm, outer diameter of 87 mm, height of 14.5 mm, and the number of turns is 300 turns. The measured ac losses were compared with the conventional theory based on the critical state model. In the region of low transport current, the theoretical results agreed well the experimental results. We also investigated the distribution of the sc losses in the coil to study the effects of magnetic field distribution on ac losses.

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  • Performance of DC reactor type fault current limiter using high temperature superconducting coil Reviewed

    M Yamaguchi, S Fukui, T Satoh, Y Kaburaki, T Horikawa, T Honjo

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   9 ( 2 )   940 - 943   1999.6

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    The purpose of this work is to study a de reactor type fault current limiter(FCL) using high temperature superconducting(HTS) coil which is connected with the secondary winding of a transformer through a diode bridge. The high temperature superconductors provide the advantages of a higher temperature operation and they are preferably applied to the de reactor type fault current limiters, where a superconducting coil can be operated at both low voltage and de current. We propose a de reactor type three-phase FCL incorporating only one HTS coil and present its test result. Three-phase FCL for 6.6 kV-2000 A requires one HTS coil of 2.9 MJ.

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  • AC loss of multifilamentary superconducting AC wire caused by longitudinal and azimuthal AC magnetic field components Reviewed

    S Fukui, K Negishi, O Tsukamoto, K Miyashita, K Fukuda

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   9 ( 2 )   825 - 828   1999.6

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    AC loss characteristics of multifilamentary NbTi AC wires under AC external magnetic field were experimentally and theoretically investigated. We measured AC transport current losses of AC wires with various twist pitches under the AC external magnetic field which included longitudinal and transverse components. It was shown by the measurement that the AC transport current losses decreased with decreasing the twist pitches when the external and self longitudinal fields were in the same direction. The measured dependence of the AC losses on the twist pitches and the applied longitudinal field component were well explained by our previously derived model. We also theoretically estimated the AC losses caused by the longitudinal and azimuthal field components. It was found that the AC losses can be substantially reduced by properly selecting the twist pitch and the external longitudinal field component.

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  • Dependence of AC transport current losses of HTS wires on their structures and synthesizing processes Reviewed

    O Tsukamoto, D Miyagi, S Ishii, N Amemiya, S Fukui, O Kasuu, H Ii, K Takeda, M Shibuya, M Mimura, K Hayashi, H Yoshino

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   9 ( 2 )   1181 - 1184   1999.6

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    HTS wires of various structures and synthesizing processes are being developed for power apparatus applications in Super-CM project. AC transport current losses of four of those wires were measured by an electric method using a lock-in amplifier, Measured wires are a Bi2212 rod fabricated by the laser pedestal growth method, a Y123 tape fabricated by the pulsed laser deposition and multilayered Bi2223/Ag sheathed wires of square and tape shapes. In this paper, based on measured data, dependence of AC transport current losses of HTS wires on their structures and synthesizing processes is discussed.

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  • Influence of thermal expansion of coil bobbins made of DFRP and GFRP on quench characteristics of superconducting coils Reviewed

    T Takao, K Watanabe, T Kubosaka, T Suzuki, T Kashima, A Yamanaka, S Fukui

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   9 ( 2 )   1133 - 1136   1999.6

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    We have excited two types of superconducting coils having same specifications. One is made of DFRP (Dyneema(R) fiber reinforced plastic) bobbins which expands during cooling process from room temperature to liquid helium temperature. The other is made of GFRP (glass fiber reinforced plastic) bobbins which contract during the cooling process. Firstly, we have numerically estimated changes of winding tensions of the two types of the coils by the cooling down. And then, training behaviors of the DFRP and GFRP coils wound with the same winding tension at room temperature were measured. Influence of quench currents in the training quenches and the number of quenches to reach to the maximum currents on the winding tensions at liquid helium temperature is systematically discussed.

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  • AC loss of low temperature superconducting AC wire caused by longitudinal and azimuthal AC magnetic field components Reviewed

    S Fukui, O Tsukamoto, K Negishi

    PHYSICA C   310 ( 1-4 )   142 - 146   1998.12

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    We investigated the AC loss characteristics of a low temperature NbTi AC wire by measuring the AC transport current losses in the external AC magnetic field whose components are the longitudinal and transverse ones. The measurement results showed that the AC losses were significantly dependent on the directions and magnitudes of the external longitudinal field component. The AC losses caused by the longitudinal and azimuthal field components were estimated by our previously derived model. The theoretical results well explained the dependence of the AC losses on the longitudinal field components. It was also shown that the AC losses can be substantially reduced by the proper choice of the twisting way. (C) 1998 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0921-4534(98)00450-X

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  • Analysis of AC loss and current distribution of co-axial multi-layer cable Reviewed

    T Hirasawa, S Fukui, M Yamaguchi, T Satoh, O Tsukamoto

    INTERNATIONAL CRYOGENIC ENGINEERING CONFERENCE 1998   503 - 506   1998

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    An analytical model to estimate the AC losses and the inter-layer current distributions of co-axial multi-layer cable conductors was developed. The interlayer current distributions and the AC losses were numerically calculated and their dependence on the twist pitches and directions of the cables was evaluated. It was shown that when the twist pitches were longer than 200mm, the AC losses and the current distributions of the cables were not clearly dependent on the twist directions. It was also shown that the AC losses decreased and the uneven current distributions improved by decreasing the twist pitches less than 150mm.

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  • Test of DC reactor type fault current limiter using high temperature superconducting coil Reviewed

    R Yamaguchi, S Fukui, T Satoh, Y Kaburaki, T Horikawa, T Honjo

    INTERNATIONAL CRYOGENIC ENGINEERING CONFERENCE 1998   391 - 394   1998

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    A number of fault current limiters(FCL) have been proposed, but so far they are not installed in the power grid because of cost, performance and others. The purpose of this work is to study DC reactor type current limiter using high temperature superconducting coil A three-phase de reactor type fault current limiter composed of only one superconducting coil is proposed.

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  • AC losses of AC superconducting cable due to transport current in external AC magnetic field Reviewed

    S. Fukui, O. Tsukamoto, N. Amemiya, K. Miyashita, M. Hakamata

    IEEE Transactions on Applied Superconductivity   7 ( 2 )   282 - 285   1997.6

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    DOI: 10.1109/77.614485

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  • Magnetic instability of AC multifilamentary wire due to transport current and its dependence on phase of external AC magnetic field Reviewed

    S. Fukui, M. Ito, O. Tsukamoto, N. Amemiya

    IEEE Transactions on Appiled Superconductivity   7 ( 2 )   227 - 230   1997.6

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  • AC Loss Due To Longitudinal and Azimuthal Magnetic Field Components of AC Ultra-fine Multifilamentary Superconducting Wire Reviewed

    FUKUI Satoshi, TSUKAMOTO Osami, AMEMIYA Naoyuki

    The Transactions of the Institute of Electrical Engineers of Japan. B A Publication of Power and Energy Society   117 ( 5 )   687 - 699   1997.4

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  • Dependence of magnetic instability of AC superconducting wire on phases of external AC magnetic field Reviewed

    M. Ito, S. Fukui, O. Tsukamoto, N. Amemiya

    IEEE Transactions on Magnetics   32 ( 4 )   2850 - 2853   1996.7

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  • DEPENDENCE OF SELF-FIELD AC LOSSES IN AC MULTIFILAMENTARY COMPOSITES ON PHASE OF EXTERNAL AC MAGNETIC-FIELD Reviewed

    S FUKUI, O TSUKAMOTO, N AMEMIYA, HLASNIK, I

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   5 ( 2 )   733 - 736   1995.6

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    We have measured the self magnetic field AC losses of a typical AC multifilamentary superconducting wire in an AC transverse external magnetic field at 50 Hz. The experimental results show that the self field AC losses are much higher than the transverse field AC losses and strongly depend on the phase difference between the transport current and the background field. We derived a theory to estimate the dependence of the self field AC losses on the phase of the external field based on the critical state model. In the paper, the measured loss characteristics are compared with the theoretical results. The theoretical model well explains the measured loss characteristics.

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  • PECULIARITIES IN ELECTROMAGNETIC BEHAVIOR OF MF NBTI COMPOSITES FOR AC USE Reviewed

    I. HLASNIK, S FUKUI, N AMEMIYA, O TSUKAMOTO, N IKEDA, T KUMANO, E SUZUKI, M POLAK, J KOKAVEC, L KREMPASKY, P, KOTTMAN

    IEEE TRANSACTIONS ON MAGNETICS   30 ( 4 )   1681 - 1686   1994.7

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    The paper presents results obtained in the study of the current - voltage characteristics, critical and quenching currents as well as of the AC transport current and magnetization losses in four series of fine filament NbTi composites prepared by Showa Electric Wire & Cable Co., Japan. Complementary measurements have been made also on a commercially available type T AC superconducting wire produced by GEC Alsthom Company, France.
    The samples differ in filament diameter, matrix thickness between filaments and in the number and structure of filament bundles in the composite. In two series of samples barrier type artificial pinning centers have been introduced to increase J(c) and decrease the normalized magnetization losses. The conclusions concerning the optimization of multifilamentary composites and cables for AC use at low working magnetic field are briefly reviewed.

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  • ELECTRIC-FIELD AND LOSSES AT AC SELF-FIELD MODE IN MF COMPOSITES Reviewed

    S FUKUI, I HLASNIK, O TSUKAMOTO, N AMEMIYA, M POLAK, P KOTTMAN

    IEEE TRANSACTIONS ON MAGNETICS   30 ( 4 )   2411 - 2414   1994.7

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    Studies of the current-voltage characteristics of typical superconducting wires under static and dynamic conditions up to 50 Hz frequency have revealed much higher instantaneous local loss power densities in an external DC magnetic field than those which occur by magnetization in a transverse AC magnetic field. In this paper, the measured loss characteristics are compared with theoretical ones derived from the critical state model, and the self field AC losses are also estimated. Possible errors that can result by applying the critical state model are discussed.

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  • SELF-FIELD EFFECT AND CURRENT-VOLTAGE CHARACTERISTICS OF AC SUPERCONDUCTORS Reviewed

    M POLAK, HLASNIK, I, S FUKUI, N IKEDA, O TSUKAMOTO

    CRYOGENICS   34 ( 4 )   315 - 324   1994.4

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    Current-voltage characteristics of two superconducting wires for a.c. use in d.c. magnetic fields up to 1 T were studied. They were measured with d.c. transport current as well as with sinusoidal a.c. transport current at frequencies up to 50 Hz. Voltage signals due to the self-field effect were obtained and analysed. The measured self-field voltage is also compared with that obtained from calculations based on the critical state model. The self-field losses were estimated by numerical integration of the measured self-field voltage multiplied by instantaneous transport current.

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  • VERY SENSITIVE ELECTRIC METHOD FOR AC LOSS MEASUREMENT IN SC COILS Reviewed

    J. Kokavec, I. Hlasnik, S. Fukui

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   3 ( 1 )   153 - 155   1993.3

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    Because the inductive component of the voltage across a superconducting coil is 10(2) - 10(4) times larger than its loss component, in the most of electric methods for AC loss measurements compensating voltage proportional to partial derivative I/partial derivative t is needed, I being the current in the coil.
    This paper presents a description of an air-core transformer whose mutual inductance M can be smoothly changed in a very large interval and the secondary voltage of which has a negligible phase shift with regard to partial derivative I/partial derivative t in the primary as well as strongly suppressed noise voltage.
    It also describes a very sensitive method of measuring AC losses in superconducting coils based on the use of such mutual as well as of a selective nanovoltmeter. This method eliminates the need off an integrator with small drift and phase shift error, of a high resolution voltage divider with sliding contact and of a shunt resistor with small phase shift which are required by other analog electric methods.
    Experimental compensating coil and their parameters as well as AC Toss measurements in different superconducting coils are also described.

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  • INFLUENCE OF STRUCTURE OF FINE FILAMENT NbTi COMPOSITE ON ITS ELECTROMAGNETIC CHARACTERISTICS Reviewed

    I. Hlasnik, O. Tsukamoto, S. Fukui, T. Kumano, M. Polak, J. Kokavec, M. Majoros, Krempasky, E. Suzuki

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY   3 ( 1 )   1370 - 1373   1993.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    The study of the influence of filament diameter d(f), filament spacing d(n) and of B on critical current density J(c) and AC losses p(s) in one type of fine filament composite (FFC) has revealed 2 components of J(c), bulk and surface critical current density J(cb) and J(cs), respectively. A simple relation between them, J(c) and geometrical parameters of FFC including those with different types of artificial pinning centers (APC) is formulated. It is used to explain measured J(c)(B, d(f)) dependence in FFC with island type APC as well as to discuss the prospects of both types of APC in FFC for AC use. To verify the obtained theoretical results another series of FFC samples with sheet type APC has been prepared and measured. Experimental values of J(c)(B, d(f)) obtained in this series samples are smaller than expected. One possible reason for this difference is suggested.

    Web of Science

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  • INFLUENCE OF STRUCTURE OF FINE FILAMENT NBTI COMPOSITE ON ITS ELECTROMAGNETIC CHARACTERISTICS Reviewed

    I HLASNIK, O TSUKAMOTO, S FUKUI, T KUMANO, M POLAK, J KOKAVEC, M MAJOROS, KREMPASKY, E SUZUKI

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL 3, NO 1, MARCH 1993 PTS 2-4   3 ( 1 Pt 3 )   1370 - 1373   1993

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:I E E E  

    DOI: 10.1109/77.233644

    Web of Science

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  • VERY SENSITIVE ELECTRIC METHOD FOR AC LOSS MEASUREMENT IN SC COILS Reviewed

    J KOKAVEC, HLASNIK, I, S FUKUI

    IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL 3, NO 1, MARCH 1993 PTS 2-4   153 - 155   1993

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    Web of Science

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Books

  • 磁性ビーズのバイオ・環境技術への応用展開

    阿部正紀, 松下伸広, 堀石七生, 山室佐益, 隅山兼治, 田中三郎, 川口春馬, 大場慎介, 弓削類, 井籐彰, 本多祐之, 松永是, 鈴木健之, 新垣篤史, 小林猛, 谷本伸弘, 西嶋茂宏, 大西徳幸, 近藤昭彦, 野田紘憙, サンドゥーアダルシュ, 福本博文, 西尾広介, 坂本聡, 宇賀均, 倉森見典, 半田宏, 富樫謙一, 板倉康彦, 八幡英夫, 玉造滋, 本間直幸, 澤上一美, 田島秀二, 玉浦裕, 岡田秀彦, 酒井保蔵, 井原一考, 渡辺恒雄, 福井聡, 笠木雄二, 三輪潤一, 式田光宏, 藤田博之, バラチャンドラン・ジャワデワン, 島田邦雄, 野地博行, 石川満

    シーエムシー出版  2012.6  ( ISBN:9784781305042

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    Total pages:ix, 310p   Language:Japanese

    CiNii Books

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  • 超電導エネルギー工学

    石山敦士, 大崎博之, 佐藤敏美, 白井康之, 高尾智明, 仁田旦三, 福井聡, 淵野修一郎, 船木和夫, 松本要

    オーム社  2006.8  ( ISBN:427420281X

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    Total pages:viii, 226p   Language:Japanese

    CiNii Books

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  • 夢を実現する超伝導

    山口, 貢, 福井, 聡

    新潟日報事業社  2004.8  ( ISBN:4861320658

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    Total pages:70p   Language:Japanese

    CiNii Books

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MISC

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Presentations

  • Development of 400 kW class induction heating device for aluminum billets using HTS magnet Invited

    S. Fukui, T.Ito, J. Ogawa, H. Kawashima, Y. Ogata, T. Sho, M. Furuse, T. Watanabe, S. Nagaya, Y. Morishita, N. Fuyama, T. Nagaoka, N. Nawachi

    35th International Symposium on Superconductivity 

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    Event date: 2022.11 - 2022.12

    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Development of Induction Heating Device of Aluminum Billets Using HTS magnet Invited

    T. Ito, S. Fukui, H. Kawashima, Y. Ogata, T. Sho, S. Sugimoto, M. Furuse, T. Watanabe, S. Nagaya, J. Ogawa, Y. Morishita, T. Nagaoka, N. Fuyama, N. Nawachi

    34th International Symposium on Superconductivity 

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    Event date: 2021.11 - 2021.12

    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Electric design and motor characteristics analysis of large capacity fully-HTS induction motor Invited

    S. Fukui, J. Ogawa, M. Nakano, T. Netsu

    34th International Symposium on Superconductivity 

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    Event date: 2021.11 - 2021.12

    Language:English   Presentation type:Oral presentation (invited, special)  

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  • Development of DC Induction Heater of Aluminum Billets for Heat Extrusion Processes Using HTS Magnet

    S. Fukui, T. Ito, H. Kawashima, Y. Ogata, M. Furuse, T. Watanabe, S. Nagaya

    12th International Forum on Magnetic Force Control 

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    Event date: 2021.10

    Language:English   Presentation type:Oral presentation (general)  

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  • Development of Test Device for Aluminum Metal Melting by Induction Heating Using DC HTS Coils Invited

    S. Fukui, J. Ogawa, T. Watanabe, S. Nagaya, M. Furuse

    32nd International Symposium on Superconductivity 

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    Event date: 2019.12

    Language:English   Presentation type:Oral presentation (invited, special)  

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  • 超伝導マグネットを用いた直流誘導加熱装置の開発状況

    福井 聡

    低温工学・超電導学会 2023年度第6回冷凍部会 例会/第4回超電導応用研究会シンポジウム  2023.12 

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    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

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  • 船舶推進機用高温超電導モータに関する研究開発の動向

    福井 聡

    低温工学・超電導学会 2022年度第1回材料研究会シンポジウム/第2回超電導応用研究会シンポジウム  2022.8 

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    Language:Japanese   Presentation type:Symposium, workshop panel (public)  

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  • 高温超伝導風力発電機の研究開発動向

    福井 聡

    低温工学・超電導学会 2022年度第1回材料研究会シンポジウム/第2回超電導応用研究会シンポジウム  2022.8 

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    Language:Japanese   Presentation type:Symposium, workshop panel (public)  

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  • 大型洋上風力用発電機における高温超伝導技術の適用可能性

    福井聡

    応用物理学会 第59回応用物理学関係連合講演会  2012.3 

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    Language:Japanese   Presentation type:Symposium, workshop panel (public)  

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Industrial property rights

  • 超電導コイル、磁場発生装置、及び、超電導コイル製造方法

    河島 裕, 伊東 徹也, 福井 聡

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    Applicant:テラル株式会社

    Application no:特願2021-083514  Date applied:2021.5

    Announcement no:特開2022-176846  Date announced:2022.11

    J-GLOBAL

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  • 磁場発生装置

    河島 裕, 伊東 徹也, 福井 聡

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    Applicant:テラル株式会社

    Application no:特願2021-071385  Date applied:2021.4

    Announcement no:特開2022-165843  Date announced:2022.11

    J-GLOBAL

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  • 無絶縁超電導コイル用の超電導体及びそれを用いた超電導コイル

    渡部 智則, 長屋 重夫, 福井 聡

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    Applicant:中部電力株式会社

    Application no:特願2017-149934  Date applied:2017.8

    Announcement no:特開2019-029285  Date announced:2019.2

    J-GLOBAL

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  • 超電導回転機

    塚本 修巳, 長屋 重夫, 鹿島 直二, 福井 聡

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    Applicant:国立大学法人横浜国立大学

    Application no:特願2009-256661  Date applied:2009.11

    Announcement no:特開2011-103708  Date announced:2011.5

    J-GLOBAL

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  • 磁気的浮上回転処理装置

    福井 聡, 小川 純, 山口 貢, 岡 徹雄, 宮崎 紳介

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    Applicant:国立大学法人 新潟大学

    Application no:特願2006-257304  Date applied:2006.9

    Announcement no:特開2008-073636  Date announced:2008.4

    Patent/Registration no:特許第4671292号  Date registered:2011.1 

    J-GLOBAL

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  • 非接触型被処理物回転処理装置

    福井 聡, 小川 純, 山口 貢, 笹原 友栄

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    Applicant:国立大学法人 新潟大学

    Application no:特願2005-363676  Date applied:2005.12

    Announcement no:特開2007-160282  Date announced:2007.6

    Patent/Registration no:特許第4644766号  Date registered:2010.12 

    J-GLOBAL

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  • 磁場移動型イオン交換樹脂およびその製造方法

    今泉 洋, 山口 貢, 福井 聡

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    Applicant:国立大学法人 新潟大学

    Application no:特願2004-051530  Date applied:2004.2

    Announcement no:特開2005-238104  Date announced:2005.9

    Patent/Registration no:特許第3951029号  Date registered:2007.5 

    J-GLOBAL

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  • 同位体濃縮方法

    今泉 洋, 山口 貢, 福井 聡

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    Applicant:新潟大学長

    Application no:特願2002-256672  Date applied:2002.9

    Announcement no:特開2004-089910  Date announced:2004.3

    J-GLOBAL

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  • 超伝導体の均流化回路

    山口 貢, 福井 聡, 佐藤 孝雄, 長澤 徹, 高畑 一也

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    Applicant:国立大学法人 新潟大学

    Application no:特願2002-131574  Date applied:2002.5

    Announcement no:特開2003-332121  Date announced:2003.11

    Patent/Registration no:特許第3706909号  Date registered:2005.8 

    J-GLOBAL

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  • 高温超電導線の交流損失低減法

    塚本 修巳, 雨宮 尚之, 福井 聡

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    Applicant:よこはまティーエルオー株式会社

    Application no:特願2001-190745  Date applied:2001.6

    Announcement no:特開2003-007150  Date announced:2003.1

    J-GLOBAL

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  • 磁気分離方法及び磁気分離装置

    西嶋 茂宏, 山口 貢, 福井 聡

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    Applicant:大阪大学長

    Application no:特願2001-125274  Date applied:2001.4

    Announcement no:特開2002-316069  Date announced:2002.10

    Patent/Registration no:特許第3538640号  Date registered:2004.4 

    J-GLOBAL

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  • 磁気分離方法及び磁気分離装置

    西嶋 茂宏, 山口 貢, 福井 聡

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    Applicant:大阪大学長

    Application no:特願2001-125269  Date applied:2001.4

    Announcement no:特開2002-316068  Date announced:2002.10

    Patent/Registration no:特許第3479690号  Date registered:2003.10 

    J-GLOBAL

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  • 磁気分離方法及び磁気分離装置

    西嶋 茂宏, 山口 貢, 福井 聡

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    Applicant:大阪大学長

    Application no:特願2001-125287  Date applied:2001.4

    Announcement no:特開2002-316067  Date announced:2002.10

    Patent/Registration no:特許第3513597号  Date registered:2004.1 

    J-GLOBAL

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  • 磁気分離方法及び磁気分離装置

    山口 貢, 福井 聡

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    Applicant:新潟大学長

    Application no:特願2001-103167  Date applied:2001.4

    Announcement no:特開2002-292305  Date announced:2002.10

    Patent/Registration no:特許第3511094号  Date registered:2004.1 

    J-GLOBAL

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  • 超電導コイル

    鹿島 俊弘, 山中 淳彦, 塚本 修, 福井 聡

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    Applicant:東洋紡績株式会社

    Application no:特願平9-162680  Date applied:1997.6

    Announcement no:特開平11-007847  Date announced:1999.1

    Patent/Registration no:特許第4006607号  Date registered:2007.9 

    J-GLOBAL

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Awards

  • 論文賞(技術)

    2024.5   低温工学・超電導学会   高温超電導マグネットを用いたアルミ押出成形用400 kW級直流誘導加熱装置の開発

    伊東 徹也, 福井 聡, 河島 裕, 緒方 康博, 古瀬 充穂, 渡部 智則, 小川 純

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Research Projects

  • Low-ac-loss and robust high-temperature-superconductor technology

    Grant number:JPMJAN24G1

    2024.4 - 2029.3

    System name:JST-ALCA-Next Program

    Awarding organization:Japan Science and Technology Agency

    Naoyuki Amemiya, Yusuke Sogabe, Toshiaki Nonaka, Satoshi Fukui

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  • 高温超電導マグネットを用いたアルミインゴット加熱装置に関する研究

    2023

    Research category:共同研究

    Awarding organization:テラル(株)

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  • 磁性材料を組込んだアルミ加熱用ホルダーの検討

    2023

    Research category:共同研究

    Awarding organization:中部電力

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  • アルミインゴット予備加熱用ホルダーの検討

    2023

    Research category:共同研究

    Awarding organization:中部電力

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  • 高出力密度アキシャルギャップ型全高温超伝導誘導電動機の基礎研究

    Grant number:22H01464

    2022.4 - 2026.3

    System name:科学研究費助成事業

    Research category:基盤研究(B)

    Awarding organization:日本学術振興会

    福井 聡

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    Grant amount:\17680000 ( Direct Cost: \13600000 、 Indirect Cost:\4080000 )

    カゴ形誘導機の2次導体を高温超伝導線材で構成して超伝導的に短絡したHTS誘導機は,誘導機と同期機の機能を併せ持った新しい回転機である。この特徴は,回転数や容量に依存せず,また界磁励磁が不要であることから,広範囲な輸送機器応用が期待できる。本研究では,HTS線材で構成が容易なコイルを用い,高空隙磁界・高導体利用率・トルク発生面最大化を同時に実現できるトロイダル巻線固定子を用いたアキシャルギャップ型高温超伝導誘導機(HTS-AGIM)を提案する。電磁界解析とHTSの電磁的・熱的特性を考慮した等価回路解析及び負荷側機械特性を連成することによりHTS-AGIMの回転機特性の解析モデルを開発し,小型モデル機を用いた妥当性検証を行い,HTS-AGIMの電磁設計手法を構築する。よって, HTS-AGIMの基盤技術の構築に寄与することを目的としている。
    2022年度は,HTS-AGIMの特性解析手法の開発及び妥当性検証,更に特性評価を行うためのベースになる小型モデル機の開発を進めた。当初の設計では,固定子用コアは,測定時のコイル組換えを容易にするために分割型を予定していた。しかしながら,機械加工上の問題が明らかになり,分割コア構造は断念して一体コア構造に設計変更を行った。それに付随して,シャフト・軸受・フレーム・電流供給端子なども再設計した。また,ヘガネス社の生産計画の関係から,プロトタイピング材の納期が遅れた。これらの影響により,固定子コア及びコアサポートの製作を優先して行った。また,固定子巻線のモデルを作製し,通電特性(磁界分布・臨界電流・交流損失の測定)を実施し,基礎データの収集と整理を行った。また,固定子コアに銅コイルを巻線して3相交流通電時の損失を測定し銅損を差し引くことにより,起磁力と鉄損の関係を導出し,今後の特性評価のための基礎データとした。

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  • High current density, high stability, and high quench protection of HTS coils in AC magnetic fields

    Grant number:22K04075

    2022.4 - 2026.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

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  • Realization of highly robust, high-performance, low-cost high-temperature superconducting coil systems without protection

    Grant number:22H01478

    2022.4 - 2025.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\17160000 ( Direct Cost: \13200000 、 Indirect Cost:\3960000 )

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  • アルミ磁気加熱用試料ホルダーの検討

    2022

    Research category:共同研究

    Awarding organization:中部電力

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  • 超伝導誘導回転機の電力機器応用のための基礎研究

    Grant number:19K04356

    2019.4 - 2024.3

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    高尾 智明, 坂本 織江, 福井 聡

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    令和4年度は、令和2年度及び3年度に引き続き新型コロナウイルスによる様々な制約の影響を受けたものの、幾つかの実験を実施し、ある程度の成果をあげることができた。具体的には、研究計画調書の研究目的、研究方法などにて記載した③-2フライホイールを用いた瞬低補償装置の検討である。
    SIMにフライホイールを付け、例えば工場の電源系に連系して通常時は空転させておき、電源の電圧が低下したときにはフライホイールの慣性で発電機として電圧を維持し、電源の電圧が復帰した場合はそのままSIMの回転が安定に回復し通常状態に戻る。このように電力変換器を必要としない高効率の瞬時電圧低下補償装置を目指して実際に試験を行った。その結果、 1500rpmの同期速度から3秒程度の停電において発電機運転し無停電電源装置として機能し、復電後は再び電動機運転に戻ることを確認した。停電の間に負荷のため回転数が150、 300、 450rpmだけ低下する試験において、無停電電源装置の動作中に回転数や電圧が下がり過ぎた場合には、再度の同期引き込みが発生して復帰までに時間が掛かる点が見られたが、すべての条件において無停電電源装置として機能することが実証できた。
    このようにコロナ禍において実現できなかった幾つかの実験を実施することができ一定の進捗があったが、まだ十分でない状況である。

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  • Study on HTS Coil with High Stability and Robustness for High Speed Aluminum Metal Melting Devices

    Grant number:19K04347

    2019.4 - 2022.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Satoshi Fukui

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    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    The first purpose of this study is to verify the usefulness of the proposed no-insulation coil system using a parallel HTS tape conductor to obtain the high stability and high operational reliability required for the HTS coil system, which is the most important element for the practical application of the aluminum induction heating system using HTS coils. The second purpose of this study is to demonstrate a coil system that can be used in a practical induction heating system using HTS coils. The local normal transition characteristics were investigated experimentally by using small test coils and the experimental results were analytically verified. The practical scale HTS coil system for the aluminum induction heating device was also developed and its performance was evaluated.

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  • 深部加熱が可能で抜群の省エネルギー化を実現する革新的な磁気加熱式によるアルミ押出加工用アルミビレット加熱装置の実用化開発

    2019 - 2021

    System name:戦略的基盤技術高度化支援事業

    Awarding organization:中小企業庁

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    Authorship:Coinvestigator(s) 

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  • 磁気加熱用アルミ試料ホルダーの構造検討

    2018

    Research category:共同研究

    Awarding organization:中部電力

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  • 極端技術に基づく超伝導交流損失の低減をねらう国際共同研究ネットワークの強化

    2017 - 2019

    System name:頭脳循環を加速する戦略的国際研究ネットワーク推進プログラム

    Awarding organization:日本学術振興会

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  • 磁気加熱用アルミ融液ホルダーの構造検討

    2017

    Research category:共同研究

    Awarding organization:中部電力

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  • Study on High Speed Aluminum Metal Melting Technique Using HTS Coils

    Grant number:16K14210

    2016.4 - 2018.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Challenging Exploratory Research

    Awarding organization:Japan Society for the Promotion of Science

    Fukui Satoshi

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    Grant amount:\3640000 ( Direct Cost: \2800000 、 Indirect Cost:\840000 )

    Fundamental studies to develop high speed aluminum metal melting technology using HTS coils were performed in this study. A numerical model to analyze the induction heating of aluminum metal by rotating it in DC magnetic field was developed. The heating experiment of aluminum specimen was done and the temperature increase of the aluminum specimen was measured. It was shown that the numerical results were well agree with the experimental results. A test device for aluminum metal melting by the induction heating using HTS coils was designed using the numerical electromagnetic and thermal analysis. The results of electromagnetic design illustrated the feasibility of HTS coils using the commercial HTS wire. The time-varying reaction magnetic field due to the eddy current in the aluminum material was analyzed. The numerical results showed that, by placing the electromagnetic shield, the reaction magnetic field could be reduced to the level not to affect the stability of HTS coils.

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  • 電動アシスト自転車用高トルク、センサレスSRモータを用いたドライブユニットの開発

    2016 - 2018

    System name:戦略的基盤技術高度化支援事業

    Awarding organization:中小企業庁

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  • Study of magnetic separation technology for nickel collection from a electroless nickel plating waste fluid

    Grant number:15H03550

    2015.4 - 2018.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    OKA TETSUO

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    Grant amount:\13000000 ( Direct Cost: \10000000 、 Indirect Cost:\3000000 )

    The magnetic separation technology to collect a nickel ingredient was studied
    and developed the study at which recycling of rare metal resources, reduction in processing waste fluid and a longer life of plating liquid are aimed, which was put into effect from the plating waste fluid, which is discharged from the electroless nickel plating process used for auto parts and an electronic component. Because a obtained nickel-sulfate crystal recycles the nickel-phosphate ion generated by a plating reaction, which has magnetism, we can separate this by the magnetic field and reuse as a raw material in the plating process.

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  • 磁気分離法による大容量ペプチドライブラリー対応自動ファージディスプレイ技術の開発

    2015 - 2017

    System name:戦略的基盤技術高度化支援事業

    Awarding organization:中小企業庁

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  • 磁気加熱用超電導磁場発生装置の実用化の課題整理と検討

    2015

    Research category:共同研究

    Awarding organization:中部電力

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  • Study on AC Loss Reduction in HTS Coils for Armature Winding of AC Rotational Machines

    Grant number:26289072

    2014.4 - 2017.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    Fukui Satoshi

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    Grant amount:\16120000 ( Direct Cost: \12400000 、 Indirect Cost:\3720000 )

    In this study, to investigate applicability of high temperature superconducting (HTS) coils to armature winding of AC rotational machines, test devices to evaluate AC loss characteristics in HTS coils combined with iron core were developed and AC loss reduction in HTS coils was studied. Based on the electromagnetic field analysis using FEM, it was found that the perpendicular magnetic field can be reduced by properly arranging the magnetic material around the HTS coil winding. By using test devices for the 1-phase and 3-phase AC loss measurements, the AC loss reduction by arranging magnetic materials around the HTS coil winding was demonstrated.

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  • リラクタンス型電動発電機の最適化設計に関する基礎研究

    2014

    Research category:共同研究

    Awarding organization:羽衣電機

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  • 磁気加熱用超電導磁場発生装置の磁気回路の詳細設計

    2014

    Research category:共同研究

    Awarding organization:中部電力

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  • 10MW超級風車の調査研究

    2013 - 2014

    System name:風力等自然エネルギー技術開発/風力発電高度実用化研究開発(古河電気工業式会社からの再委託)

    Awarding organization:新エネルギー・産業技術総合開発機構

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  • セシウムの動態解析に基づく除染シナリオの構築と磁気力制御型除染法の開発

    2013 - 2014

    System name:環境研究総合推進費

    Awarding organization:環境省

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  • 磁気加熱用超電導コイルの要素試験機評価に基づく実用化の検討

    2013

    Research category:共同研究

    Awarding organization:中部電力

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  • 低炭素社会を支える輸送機器用超伝導回転機システム

    2012 - 2017

    System name:戦略的創造研究推進事業 先端的低炭素化技術開発(ALCA)

    Awarding organization:科学技術振興機構

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  • 磁気加熱に関する調査研究

    2012

    Research category:共同研究

    Awarding organization:中部電力

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  • Study on Reduction Method of AC Loss and Optimization of HTS Coil for Rotating Machines

    Grant number:23560320

    2011 - 2013

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    FUKUI Satoshi

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    Grant amount:\5460000 ( Direct Cost: \4200000 、 Indirect Cost:\1260000 )

    Power meter method and boil-off method were developed to measure the AC loss in HTS coils in this study. These methods were applied for the AC loss measurement of HTS model coil. The theoretical model to analyze the AC in HTS coil based on the AC loss data of the HTS tape was also developed. It was confirmed that the measured results of the AC loss in the model coils by the power method and the boil-off method were well explained by the theoretical model. The optimization of the HTS coil used in a rotational machines was theoretically investigated by using the model. The reduction method of the AC loss in the HTS coil by introducing the tilt-winding was proposed and the effect of AC reduction was experimentally verified.

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  • 磁気分離法を用いた除染技術に関する調査研究

    2011

    Research category:共同研究

    Awarding organization:中部電力

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  • 高温超電導ケーブルの低交流損失化

    2010 - 2013

    System name:(新エネルギー・産業技術総合開発機構「超電導技術研究開発/高温超電導ケーブル実証プロジェクト」の再委託)

    Awarding organization:住友電気工業(株)

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  • 大出力超伝導回転機器に向けたキーハードの開発

    2009 - 2013

    System name:戦略的イノベーション創出推進事業(S-イノベ)

    Awarding organization:科学技術振興機構

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  • Development of Precise-controlled Magnetic Drug Delivery System

    Grant number:21360133

    2009 - 2012

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    NISHIJIMA Shigehiro, AKIYAMA Yoko, NAKAGAWA Takashi, HUKUI Satoshi

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    Grant amount:\17810000 ( Direct Cost: \13700000 、 Indirect Cost:\4110000 )

    The objective of this study is to construct the methods of MDDS (magnetic drug delivery system) to accumulate drugs in the local deep part of the body. Two methods; local accumulation of ferromagnetic drug with ferromagnetic needle in the external magnetic field and non-invasive accumulation by rotating MDDS were studied. As a result, the possibility of local accumulation of ferromagnetic drug in the deep part was shown

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  • Fundamental study of face-to-face settled superconducting magnetron sputtering technique

    Grant number:20560006

    2008 - 2010

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    OKA Tetsuo, FUKUI Satoshi, OGAWA Jun, SHIMIZU Hidehiko

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

    We constructed a novel type of magnetron sputtering device characterized by its strong magnetic field generation with face-to-face settled target cathodes. By using the device, strong magnetic field of 3.2 T enabled us to obtain a novel sputtering source. As a result of experimental operations, we observed DC plasma discharges under the circumstance of strong field 1 T with the power application up to 650 V. The difference of the property of plasma discharges showed us a plasma magnetron discharge which varied its shapes with changing magnetic field distributions. The deposition rate of 0.06nm/min derived from the results of rate measurement by ICP analysis was estimated as same level of commercially-supplied sputtering devices, which showed possible high rate sputtering machines. We succeeded in obtaining a new sputtering equipment and actual deposition of copper film with several ten times faster than usual magnetic field equipped in ordinary sputtering machines. Sustainable and stable plasma discharge was observed by containing plasma and magnetic field between the poles.

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  • Study of Optimization Design of HTS Power Transmission Cable Based on AC Loss Minimization

    Grant number:20560261

    2008 - 2010

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    FUKUI Satoshi, OGAWA Jun

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

    In this study, an electric measurement method of AC losses in multi-layer spiral cables was developed. The measurement method was applied to measure the AC loss in the 4-layer spiral cable with 2-layer shield conductor made by Bi-2223 HTS tapes. The measured data were compared with the numerically calculated AC losses and the good agreement was confirmed. Several short model cables made by Y-123 HTS tapes were fabricated by changing tape-to-tape gap width and number of tapes. The AC losses in these short model cables were measured and compared with the numerical data. It is confirmed that the measured AC loss dependences on tape-to-tape gap width and tape numbers were clearly explained by the numerical model. Based on the numerical model, the relationship between the AC loss in the multilayer cable made by Y-123 HTS tapes and the cable geometrical parameters were systematically investigated. Among this study, the useful knowledge for the AC reduction was obtained.

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  • スピン処理装置用浮上回転機構の要素試作研究

    2008 - 2010

    System name:(科学技術振興機構 独創的シーズ展開事業 委託開発「超電導体利用半導体製造用スピン処理装置」の再委託)

    Awarding organization:(株)エムテーシー

    福井 聡

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  • カップ型超電導回転機に関する調査研究

    2008 - 2009

    Research category:共同研究

    Awarding organization:中部電力

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  • 高温超電導コイルの交流損失解析

    2008 - 2009

    System name:((独)石油天然ガス・金属鉱物資源機構「直接起震方式による次世代型人工震源の研究」の再委託)

    Research category:共同研究

    Awarding organization:(株)超電導機構

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  • 周期的空間勾配のある強磁場下での反磁性有機微小球の微細配列手法の開発

    2007

    System name:地域イノベーション創出総合支援事業 シーズ発掘試験

    Awarding organization:科学技術振興機構

    福井 聡

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    ポリスチレンなどの有機高分子材料のサブミクロン微小球を基板上に規則的に精度良く配列することができれば,光学用素子等としてのニーズがある。ポリスチレン等は弱い反磁性であり,強磁場に対しては反発する性質を持つ。本研究では,この性質を利用して,超伝導マグネットによる強磁場下で,有機微小球を基板上に配列させる手法を研究する。

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  • 高温超伝導バルクマグネットを用いた磁気クロマトグラフィーの開発

    2006

    System name:地域イノベーション創出総合支援事業 シーズ発掘試験

    Awarding organization:科学技術振興機構

    福井 聡

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    近年の超伝導マグネット技術の進歩に伴い,超伝導マグネットによる強磁場を利用した磁気分離の研究は従来から広く研究されてきた。磁気分離とは空間的に勾配のある磁場中で磁性粒子に働く磁気力により,排水中の有害物質や有用物質を分離する技術である。申請者は,平成11~15 年度に日本学術振興会の未来開拓学術研究推進事業プロジェクト「強磁場下における物質と生体の挙動- 強磁場下の磁気分離による環境改善と資源循環利用-(プロジェクトリーダ:渡辺恒雄現首都大学東京・教授)」に参画し,新規の磁気分離装置の研究開発を行った。その研究成果を発展させて,強磁場環境の応用として単なる粒子の分離のみならず,空間勾配のある強磁場中に細管チャネルを配置してその中に磁性や大きさの異なる複数の磁性粒子が懸濁した流体を流し,細管中に発生する流速分布と磁気力を利用して磁性や粒子径の応じた進行速度差生じさせて,特定の磁性粒子を分離・精製する新規の磁気クロマトグラフィーを考案し,これまで数値解析を中心に研究を行ってきた。このアイデアによれば,磁場の空間配位や細管の直径をコントロールすることにより,理論的にはナノオーダからミクロンオーダの常磁性粒子まで広範囲にハンドリングできる。これまでは,空間勾配の大きい強磁場を発生する方法として複合超伝導マグネットを用いることを検討していたが,マグネットが高価になりすぎ実現性に乏しい。近年,大直径の高性能高温超伝導バルクが開発され,比較的安価に入手が可能になった。強磁場に着磁した高温超伝導バルク周辺の磁場は空間的に大きな勾配を有するので,これを用いれば安価で簡便な構造の磁気クロマトグラフィーが実現できると考えられる。本研究では,高温超伝導バルクを用いた磁気クロマトグラフィーについて,まず数値解析により磁性粒子の分離特性を系統的に整理する。数値解析結果に基づき,直径50nm/磁化率10-2 程度の常磁性粒子を選択分離できるモデル実験装置を作り,所望の特性が得られるかどうかを検証する。よって,装置の実用化に向けた課題を抽出し,その解決法を明らかにする。

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  • 超伝導磁気浮上回転装置の研究・開発

    2005 - 2006

    Research category:共同研究

    Awarding organization:(株)新潟TLO

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  • Technology creation of HTS magnet for superconducting magnetic energy storage

    Grant number:17560251

    2005 - 2006

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    YAMAGUCHI Mitsugi, FUKUI Satoshi, OGAWA Jun

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    Grant amount:\3300000 ( Direct Cost: \3300000 )

    As for the stored energy density, the solenoid coil has the larger value. On the other hand, the toroidal field coil has the least leakage flux. The primary concern of HTS SMES coil is the reduction of the cost, while securing superconducting coil performance.
    For this purpose, the required HTS tape length needs to be as short as possible. The critical current and n values of HTS tapes depends on the magnetic fields as well as its field angle to the tapes. Therefore, the performance of magnets wound with HTS tapes needs to be analyzed based on above factors. The current-voltage characteristics of the HTS coil were analyzed by means of fitting equations of the critical current and n value obtained from the measured values of the Bi2223/Ag tape. The stored energy of four kinds of coil arrangement was analyzed, thereby pursuing the shortest length of HTS tapes.
    The toroidal field coil comprised of 12 element coils requires 58% longer HTS tapes than the solenoidal coil to store the energy of 100 kJ, but 0.01 T leakage field region at the mid-plane is about a half of the solenoid coil. These properties of two-pole coil and quadrupole coil are situated between them.

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  • 高温超伝導バルクによる磁気浮上を応用した非接触スピン処理装置の開発

    2005

    System name:地域イノベーション創出総合支援事業 シーズ発掘試験

    Awarding organization:科学技術振興機構

    福井 聡

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    半導体フォトマスクのコーティング。洗浄。エッチング。レジストプロセスではスピン処理を用いるが,回転装置の軸受から異物放出が起こり,フォトマスク周囲のクリーン度が低下し低品質化或いは歩留まり低下の原因となっており,この問題の解決が切望されている。本問題を解決するためには,スピン処理装置のターンテーブル部分をクリーンベンチ内に完全隔離し,クリーンベンチ外部からの遠隔力により浮上回転させる非接触のスピン処理装置の開発が必要不可欠である。本研究では,高温超伝導体と希土類系永久磁石を組合わせた浮上方式を提案する。この組み合わせにより,外部制御を必要とせずにアクティブ制御以上のロバスト性を有する磁気浮上系を容易に構成できる。この浮上方法と永久磁石による磁気カップリングを組合わせた回転磁気浮上をスピン処理装置に応用するための基礎研究を行う。本研究では,直径300mm/重量2kg程度の円盤を,浮上高10mm/回転数2000rpmで安定浮上む回転させるモデル装置を開発する。モデル機により,高温超伝導体の磁場捕捉特性,リップル磁場中の高温超伝導体の損失特性,浮上。回転安定性,始動。制動制御特性を評価する。よって,実用化に向けた課題を抽出しその解決方法を明らかにする。

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  • 酸化物高温超伝導線材・集合導体の統合的交流損失低減手法の研究

    Grant number:15760194

    2003 - 2004

    System name:科学研究費助成事業

    Research category:若手研究(B)

    Awarding organization:日本学術振興会

    福井 聡

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    Grant amount:\3700000 ( Direct Cost: \3700000 )

    本研究では線材技術が最も進歩しているビスマス系・イットリウム系線材とそれらの集合導体に主たる焦点をあて,応用機器での電磁環境に即した線材から集合導体までの各構造をそれぞれ統合的に設計し,交流損失を現状より大幅に低減する手法を明らかにすることを目的する。酸化物高温超伝導線材の交流損失メカニズムを解明するため,今年度の研究ではまず,イットリウム系線材に直流及び交流磁界を印加し,線材への外部磁界の印加方向を変化させながら,交流通電時の通電損失・磁化損失の同時測定を行った.同時にビスマス系線材についても同様の測定を行い,特性の類似点・相違点を明確化し,損失特性を印加磁界の形態別に体系的に整理した。既に我々が開発した解析モデルによる解析結果と上記測定で得られた損失データを比較し,モデルの妥当性を検証した。その結果,我々の解析モデルは,測定で得られた線材の交流損失特性を良く説明できることがわかった。また,酸化物テープ線材を多数本束ねた集合導体の損失特性を解析するモデルを開発した。この集合導体解析モデルに基づき,集合導体において大幅な低損失化と電流分布の均一化による大容量化が同時に図れる集合導体構造についての定量的検討を行った。今後は本研究の成果を踏まえ,集合導体化により線材単独の場合より損失が低減できる条件を理論的に導き,線材及び集合導体を試設計する。

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  • 磁気分離法を活用した新規環境改善技術の研究動向

    Grant number:15631003

    2003

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    酒井 保藏, 渡辺 恒雄, 福井 聡, 西嶋 茂宏, 荷方 稔之, 宮越 順二

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    Grant amount:\3400000 ( Direct Cost: \3400000 )

    H.15年4月下旬 交付申請書作成のための打ち合わせを行なった。
    都立大で交付申請書作成のための打ち合わせを特定領域申請を考慮しつつ行なった。
    H.15年6月下旬 第1回全体会議 分担分野での調査発表会を行なった。効果的な特定領域研究のための組織化。研究分担者による既往の研究や各自の研究分野についての発表および討論会を行なった。特定領域の効果的な研究推進計画を構築するための情報の集約と研究組織の構成案を決定し、また、追加の研究者について情報交換を行なった。
    H.15年8月中旬 特定領域申請時のグループリーダー予定者を中心とした会議を行なった。
    特定領域申請時のグループリーダーを中心として、特定領域申請のための打ち合わせを行なった。各グループの計画についての詳細な研究計画についての討論を行い、全体としての合理的な研究計画を作成する。これらの結果をもとに計画班リーダーは各グループ計画調書作成を行なった。
    H.15年10月末 特定領域申請時のグループリーダー予定者を中心とした会議を行なった。特定領域申請のための最終打ち合わせ。および都立大に集合して、申請書の最終修正を行なった。
    H.15年2月下旬 第2回全体会議 分担分野での調査発表および討論
    特定領域申請結果の可否にかかわらず、今後の磁気分離研究プロジェクトをどのように展開するかを議論した。ヒアリングまでいった場合の準備、不可だった場合の次年度に向けての体制についても議論した。
    H.16年3月下旬 イギリスでの磁気分離研究動向調査
    イギリスにおいて磁気分離を浄水処理に実際に用いているプラントの見学を行なった。また、関連企業や関連研究者と意見交換を行い、特定領域が通った場合の国際共同研究や国際共同開発についてのディスカッションも行なった。

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  • Systemization of elementary technology for high temperature superconductor AC applications based on electro-magnetics of fine structures of conductors

    Grant number:14102019

    2002 - 2006

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (S)

    Awarding organization:Japan Society for the Promotion of Science

    TSUKAMOTO Osami, AMEMIYA Naoyuki, FUKUI Satoshi, OGAWA Jun

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    Grant amount:\108810000 ( Direct Cost: \83700000 、 Indirect Cost:\25110000 )

    If technologies are developed to reduce AC losses in high temperature superconductor (HTS) to less than one tenth of those of the conventional HTS technology, more various applications of HTS become feasible than just DC applications. Our research object is to systematically develop elementary technologies to reduce the AC losses in HTS applications by deep understanding of electromagnetic phenomena of HTS. To pursue the research object we set the following research targets;
    a)To developed measurement methods of AC losses in HTS wires, assembled conductors and windings;
    b)To research and develop methods to greatly reduce the AC losses in HTS wires in electromagnetic and mechanical environment of HTS apparatuses;
    c)To research and develop design methods of structures of robust and low AC loss windings;
    We obtained the following important achievements in the term of this project.
    1)We develop a method to electrically measure the total AC losses. The validity of this electric method was proven by the simultaneous measurements with a calorimetric method.
    2)We developed a quasi-twisting method to reduce magnetization losses in coated conductors due to external AC magnetic fields by more than one order of magnitude.
    3)We showed that the losses were greatly reduced by the magnetic field produced by the neighboring conductors in the assembled conductors.
    4)Analytic method to calculate the AC losses in the coil using the loss data of wires was developed. Based on this analytic method, optimal configuration of a coil was shown to minimize the AC losses.
    5)We calculated necessary amount of copper to protect a coil wound of coated conductors from damages caused by a quench and showed a configuration of robust coils.
    With those achievements, we almost fulfill the R&D objects to develop elementary technologies to realize low AC loss HTS apparatuses.

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  • A study on S/N transition type and DC reactor type fault current limfter.

    Grant number:13650301

    2001 - 2003

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    YAMAGUCHI Mitsugi, FUKUI Satoshi

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    Grant amount:\3400000 ( Direct Cost: \3400000 )

    The purpose of this work is to study a dc reactor type as well as a dc S/N transition type fault current limiter (FCL) using high temperature superconducting(HTS) coil, which is connected with the secondary winding of a transformer through a diode bridge.
    The high temperature superconductors are preferably applied to the dc reactor or the S/N transition type fault current limiters, where a current limiting element can be operated at both low voltage and dc current. In addition, it features that this device requires only one current limiting element in three-phase power system. Further, it has a function of fault current limiting interruption(FCLI) in one of two ways ; automatic interruption of a fault current with the assistance of a bias current applied to the bridge or gate interruption by blocking thyristor's gate pulses.
    A dc hybrid three-phase fault current limiting interrupter is also feasible as a compromised device composed of an HTS reactor and an S/N transition element, set up within the reactor, connected in series each other.
    The performances of a fault current limiting interruption as for above three devices were confirmed both experimentally and analytically and their characteristics were compared.
    It was made clear that the central magnetic field per coil volume is maximal at the coil aspect ratio providing the minimum coil volume. An establishment of the unequal current prevention is being required for assembled conductors. A method, which makes the current flow equal in each strand, is devised by means of interphase reactors, and its effectiveness was confirmed experimentally.
    The target of research and development to realize S/N transition type and dc reactor type fault current limiter was made clear by the above researches.

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  • 酸化物超伝導コーティング線材の損失メカニズムと低損失化構造の研究

    Grant number:13750244

    2001 - 2002

    System name:科学研究費助成事業

    Research category:若手研究(B)

    Awarding organization:日本学術振興会

    福井 聡

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    Grant amount:\2600000 ( Direct Cost: \2600000 )

    Y(イットリウム)系線材は長尺化の技術は進展していないが,Bi系線材の数倍以上の臨界電流密度を有することから,応用への潜在的能力を秘めた次世代線材として期待されている.本研究では材料的優位性の高いY系コーティング線材に主たる焦点をあて,ミクロな電磁現象論に立脚した低損失な線材及び導体構造の解明し,Bi系線材を越える高性能なY系線材の設計手法を系統的に研究することを目的としている.酸化物高温超伝導線材の交流損失メカニズムを解明するため,平成13年度の研究では,イットリウム系線材に直流及び交流磁界を印加し,線材への外部磁界の印加方向を変化させながら,交流通電時の通電損失・磁化損失の同時測定を行った.同時にBi系線材についても同様の測定を行い,特性の類似点・相違点を明確化する.これにより,損失特性を印加磁界の形態別に体系的に整理した.既に我々が開発した解析モデルによる解析結果と上記測定で得られた損失データを比較し,モデルの妥当性を検証した.その結果,我々の解析モデルは,測定で得られた線材の交流損失特性を良く説明できることがわかった.これらの結果を基に,平成14年度は交流損失を低減できる線材構造の検討を行い,集合導体化により線材単独の場合より損失が低減できる条件を理論的に導いた.また,積極的に臨界電流密度分布を制御し交流損失を低減できる酸化物超電導線材の断面構成の設計指針についての知見を得ることができた.

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  • 超電導基本特性測定方法に関する共同研究

    2000 - 2004

    Research category:共同研究

    Awarding organization:超電導発電関連機器・材料技術研究組合

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  • Study on Slow-Wave Cyclotron Maser Based on Anomalous Doppler Effect

    Grant number:12480116

    2000 - 2002

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    OGURA Kazuo, FUKUI Satoshi, ITAGAKI Koichi

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    Grant amount:\14600000 ( Direct Cost: \14600000 )

    In this research, slow-wave cyclotron maser based on the induced radiation at the anomalous Doppler cyclotron frequency has been proposed The outline of this work is summarized.
    ・Magnetic system and electron beam
    Magnetic system has been newly built. The magnetic field configuration is controlled by the current distribution of magnetic coils. And the uniform magnetic field is obtained in the range of the 414mm of the axial direction, and the 60mm of the radial direction. By controlling the magnetic field, the electron beam of about 60kV and several hundreds A is able to propagate over 360mm in a vacuum vessel.
    ・Slow-wave cyclotron maser based on the anomalous Doppler effect
    The theoretical analysis of slow-wave cyclotron maser has been published in Physical Review E as a regular article. K-band microwave generation has been investigated experimentally. Oscillation frequency is in the range of 20 to 25 GHz, and radiation power is about 100kW (about 2%) at the maximum. In a lower magnetic field region, the oscillations in non-axisymmetric mode are observed, which may be attributed to slow-wave cyclotron maser operation based on the anomalous Doppler effect. This shows the possibility of the control of the Cherenkov interaction and the slow-wave cyclotron interaction by a magnetic field.
    ・Experimental research aiming at higher frequency operation
    For higher frequency operation in millimeter wave region, a Q-band large diameter slow-wave structure is manufactured. With this slow-wave structure, the millimeter wave with a frequency of about 35GHz is obtained. Radiation power is about 30kW or less (the oscillation efficiency is about 0.4%) at the maximum, ard is about 1/4 compared with K-band experiments.
    Control with the high accuracy of a beam is required for resonance-operation with the slow-wave cyclotron interaction and the Cherenkov interaction, or stabilization operation in a lower magnetic field region. Technology for such control of large current electron beam propagation is a future subject. It is necessary to make theoretical analysis and experiment cooperate and to advance research.

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  • 酸化物線材の低損失集合化手法と特性調査

    2000 - 2001

    Research category:共同研究

    Awarding organization:中部電力

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  • 交流電気機器用超伝導線材とその集合導体及びコイルの統合的設計手法

    Grant number:11305022

    1999 - 2001

    System name:科学研究費助成事業

    Research category:基盤研究(A)

    Awarding organization:日本学術振興会

    塚本 修巳, 福井 聡, 雨宮 尚之

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    Grant amount:\32810000 ( Direct Cost: \31100000 、 Indirect Cost:\1710000 )

    3年間にわたる本研究の成果を要約すると以下のようになる.
    a) 高温超伝導線材の交流磁界下で交流通電をした場合の交流損失を高精度で評価する方法を開発した.特に従来測定が困難とされていた交流磁界下で交流通電した場合の線材に発生する全損失を電気的に測定する方法を開発した.
    b) 種々のBi系およびY系の線材について交流損失の測定を実施し,集合導体化,コイル化した場合の損失評価をするためのデータを収集した.また,測定データに基づき交流損失を解析モデルを構築し,線材における交流損失発生の機構を示した.これにより高温超伝導線材は低温超伝導線材に比較し超伝導から常伝導への転移が緩やかであるが,基本的には損失の発生機構は低温超伝導と同様であることが示された.
    c) バリア線材などフィラメント間のブリッジングを抑制した線材においては低温超伝導導体と同様な電磁気的特性を示し,従って,低温超伝導体の交流特性解析と同様な解析手法が適用できることが示された.
    d) 上記b)およびc)の成果により,既に我々が行ってきたマルチフィラメント低温超伝導交流線材に交流損失の研究の結果得られた交流損失の大幅な低減手法をBi系のマルチフィラメント銀シース線材に適用できることがわかり,その有効性を実験及び解析により検証した.
    e) Y系の薄膜導体の通電損失についても交流損失評価のための解析モデルを作り,実験データと対応させながら通電損失低減の方法の知見を得た.特にY系線材の製法により交流通電損失特性が異なる理由を明らかにし,損失を低減するための条件を示した.
    f) また,複数の線材を束ねた集合導体について交流通電損失の評価を行い,個々の線材と集合導体の損失特性を集合導体の構造と関係付けて示し,損失低減法を示した.
    g) 以上の成果を基に線材・集合導体・巻線までを見渡し機器の種類に応じた交流損失低減法を提案し,従来に比較して1桁の損失低減の可能を示した.

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  • 大容量交流超伝導導体の最適化設計手法の研究

    Grant number:10750205

    1998 - 1999

    System name:科学研究費助成事業

    Research category:奨励研究(A)

    Awarding organization:日本学術振興会

    福井 聡

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    Grant amount:\2400000 ( Direct Cost: \2400000 )

    大容量交流超伝導導体の最適化設計を行うには,導体の交流損失特性と安定性を評価する必要がある.これら両者は,導体のさらされる磁気的環境に大きく依存するため,実用機器における導体の使用環境を考慮して評価する必要がある.従って,本年度の研究では,上記の点を系統的に解明することまず第一の目的とした.そこで,大容量超伝導導体の交流損失を最小にし,安定性を損なわない導体構造の最適化設計手法の開発のため,それらの交流損失特性を評価した.これにあたり,まず素線およびケーブル導体として最も電流容量の小さい(6+1)本撚りケーブルの損失特性を実用電力機器の巻線中における電磁界環境を模擬した状況下で評価した.この点については,従来の我々の研究成果でも部分的には得られているが,系続的な評価は行っていなかった.今年度の研究では,まず撚りのピッチと向きを変えた数種類の素線および1次ケーブルを用意し,それらの交流損失特性と外部縦磁界の向きと大きさ,及び素線の撚りピッチとの関係について,系統的な評価を行った.その結果,外部縦磁界と素線内部に発生する自己縦磁界の向きが同じ場合,外部縦磁界の大きさと向きに対応させて素線及びケーブルの撚りピッチを適正に調整することにより,交流損失を最小化できることが明らかになった.さらに,交流損失を最小化できる素線撚りピッチの最適化条件を得る手法を開発できた.この結果を用いて,素線を36本束ねた電流容量が2kA級のケーブル導体を設計・試作し,その評価を行った.その結果,本手法の妥当性を示すことができた.これにより,交流超伝導導体の大容量化に対して,有用な知見が得られた.

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Teaching Experience

  • 電子情報通信実験IV

    2024
    Institution name:新潟大学

  • 電子情報通信実験II

    2023
    Institution name:新潟大学

  • リメディアル演習

    2022
    Institution name:新潟大学

  • 電子情報通信実験IIA

    2021
    -
    2022
    Institution name:新潟大学

  • 電子情報通信実験IIB

    2021
    -
    2022
    Institution name:新潟大学

  • 電子情報通信設計製図

    2020
    Institution name:新潟大学

  • 論文輪講II

    2020
    Institution name:新潟大学

  • 電子情報通信実験IVA

    2020
    Institution name:新潟大学

  • 論文輪講I

    2020
    Institution name:新潟大学

  • 電子情報通信実験IVB

    2020
    Institution name:新潟大学

  • 工学リテラシー入門(情報電子分野)

    2019
    Institution name:新潟大学

  • 電子情報通信実験IIB

    2019
    -
    2022
    Institution name:新潟大学

  • 電子情報通信実験IIA

    2019
    -
    2022
    Institution name:新潟大学

  • 電子情報通信概論

    2018
    Institution name:新潟大学

  • 電子情報通信実験IA

    2018
    Institution name:新潟大学

  • 電子情報通信実験IB

    2018
    Institution name:新潟大学

  • 総合技術科学演習

    2017
    -
    2022
    Institution name:新潟大学

  • 自然科学総論Ⅲ

    2015
    -
    2018
    Institution name:新潟大学

  • 技術英語入門

    2015
    -
    2016
    Institution name:新潟大学

  • 電気電子工学研究発表(外部発表)

    2014
    -
    2015
    Institution name:新潟大学

  • 電気電子工学文献詳読Ⅱ

    2013
    -
    2014
    Institution name:新潟大学

  • 電気情報工学特定研究Ⅲ

    2013
    Institution name:新潟大学

  • 電気情報工学博士セミナーⅢ

    2013
    Institution name:新潟大学

  • 電気電子工学特定研究Ⅱ

    2012
    -
    2015
    Institution name:新潟大学

  • 電気電子工学セミナーⅡ

    2012
    -
    2015
    Institution name:新潟大学

  • 電気電子工学特定研究Ⅰ

    2012
    -
    2015
    Institution name:新潟大学

  • 電気電子工学研究発表演習(中間発表)

    2012
    -
    2015
    Institution name:新潟大学

  • 電気電子工学セミナーⅠ

    2012
    -
    2015
    Institution name:新潟大学

  • 電気電子工学文献詳読Ⅰ

    2012
    -
    2015
    Institution name:新潟大学

  • 電気電子工学研究発表演習(外部発表)

    2012
    -
    2013
    Institution name:新潟大学

  • 電気情報工学博士セミナーⅡ

    2012
    Institution name:新潟大学

  • 研究発表演習・発表

    2012
    Institution name:新潟大学

  • 外国語論文解説・討論Ⅲ

    2012
    Institution name:新潟大学

  • 電気電子工学コースセミナーⅡ

    2012
    Institution name:新潟大学

  • 電気情報工学特定研究Ⅱ

    2012
    Institution name:新潟大学

  • 電気電子設計製図

    2010
    -
    2018
    Institution name:新潟大学

  • 電気電子創造設計

    2010
    -
    2016
    Institution name:新潟大学

  • 卒業研修

    2009
    Institution name:新潟大学

  • 工学リテラシー入門(電気電子工学科)

    2009
    -
    2016
    Institution name:新潟大学

  • 電気電子演習

    2008
    -
    2009
    Institution name:新潟大学

  • スタディスキルズ(電気電子工学)

    2008
    Institution name:新潟大学

  • 応用超伝導工学

    2007
    Institution name:新潟大学

  • 卒業研究

    2007
    Institution name:新潟大学

  • 送配電工学

    2007
    Institution name:新潟大学

  • 電気数理II

    2007
    Institution name:新潟大学

  • 電気機器

    2007
    Institution name:新潟大学

  • 超伝導システム特論

    2007
    Institution name:新潟大学

  • 論文輪講

    2007
    -
    2019
    Institution name:新潟大学

  • 電気電子工学実験IV

    2007
    -
    2018
    Institution name:新潟大学

  • 電気電子工学実験III

    2007
    -
    2018
    Institution name:新潟大学

  • 電気電子工学実験I

    2007
    -
    2017
    Institution name:新潟大学

  • 電気電子工学実験II

    2007
    -
    2017
    Institution name:新潟大学

  • エレクトロニクス入門

    2007
    -
    2016
    Institution name:新潟大学

  • 卒業基礎研究

    2007
    -
    2008
    Institution name:新潟大学

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