Faculty Profiles - OGAWA Jun

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岡徹雄, 平山絵梨, 金井智亮, 高橋康宏, 福井聡, 小川純, 佐藤孝雄, 横山和哉, 仲村高志

電気学会全国大会講演論文集(CD-ROM) 2014 ROMBUNNO.5-168 2014.3

Magnetic separation technique using high temperature superconducting bulk magnets and application to plating liquid waste treatment

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

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 61 ( SUPLL.1 ) 2014

A magnetic separation technique has been conducted to recycle the nickel (Ni) element from the waste fluid of electroless Ni plating processes. The experiment was operated using the face-to-face type electromagnet generating 1.96 T and the data was compared to those in the case of the high temperature superconducting bulk magnet which generates 3.45 T. In the electroless plating processes, the plating fluid containing high concentration of Ni ions is disposed after several turns of the plating cycles when the concentration of phosphite ions exceeds a certain level. In order to extract the Ni element at first, we formed the coarse Ni-sulfate crystals with the sizes over 1 mm from the Ni-phosphite precipitates by controlling the temperature and the pH value. Next, the magnetic separation experiments were operated to collect the Ni-bearing precipitate which carried the weak magnetism. Although the performance of high temperature superconducting bulk magnet is superior to that of electromagnets, as a result, we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite precipitates soon after the crystal growth began.

DOI： 10.2497/jjspm.61.S164

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Magnetic Flux-Trapping of Anisotropic-Grown Y-Ba-Cu-O Bulk Superconductors during and after Pulsed-Field Magnetizing Processes

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

11TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS2013), PTS 1-4 507 2014

Language：English Publisher：IOP PUBLISHING LTD

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-BaCu- 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 J(c) values with different distributions of the pinning centers, results in the preferential paths for the invading magnetic fluxes.

DOI： 10.1088/1742-6596/507/1/012039

Web of Science

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

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

Physics Procedia 58 74 - 77 2014

© 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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10MW超級高温超電導風力発電機の電気設計と電磁特性解析

福井聡, 伏木貫太, 小川純, 佐藤孝雄, 向山晋一, 松岡太郎, 天野俊昭, 古川真, 山崎裕文, 古瀬充穂, 淵野修一郎, 岡野眞

低温工学・超電導学会講演概要集 90th 2014

磁場侵入経路の導入を狙ったバルク超伝導体の合成

堀内拓磨, 山田幸正, 小川純, 福井聡, 岡徹雄, 横山和哉, LANGER Marco

低温工学・超電導学会講演概要集 88th 192 2013.12

種結晶の数と配置を考慮して異方的に成長させたYBCOバルク磁石のパルス着磁特性

岡徹雄, 山田幸正, 堀内琢磨, 小川純, 福井聡, 佐藤孝雄, 横山和哉, LANGER Marco

低温工学・超電導学会講演概要集 88th 191 2013.12

種結晶の位置変化による異方的な超伝導バルク磁石のパルス着磁特性

岡徹雄, 山田幸正, 堀内拓磨, 小川純, 福井聡, 佐藤孝雄, 横山和哉

電気学会電力・エネルギー部門大会論文集(CD-ROM) 2013 ROMBUNNO.379 2013.8

大型風力用高温超電導同期発電機の電気設計の検討

伏木貫太, 前澤勝, 福井聡, 小川純, 岡徹雄, 佐藤孝雄

電気学会電力・エネルギー部門大会論文集(CD-ROM) 2013 ROMBUNNO.P50 2013.8

挿入された鉄心形状による高温超伝導線材の交流損失特性への影響

伏見侑, 前川達也, 小川純, 福井聡, 岡徹雄, 佐藤孝雄

電気学会電力・エネルギー部門大会論文集(CD-ROM) 2013 ROMBUNNO.P30 2013.8

パルス着磁に適したバルク超伝導体の合成

山田幸正, 堀内拓磨, 福井聡, 小川純, 佐藤孝雄, 横山和哉, LANGER Marco, 岡徹雄

低温工学・超電導学会講演概要集 87th 67 2013.5

Dy123系超伝導バルク磁石のパルス着磁における微細組織と温度特性

木伏貴映, 岡徹雄, 太田博之, 福井聡, 小川純, 横山和哉, 村上明

低温工学・超電導学会講演概要集 87th 30 2013.5

高温超伝導バルク磁石の反復着磁による磁場捕捉挙動と発熱現象

岡徹雄, 石塚大地, 木伏貴映, 太田博之, 小川純, 福井聡, 佐藤孝雄, 横山和哉, 村上明, STOPFEL Henry

低温工学・超電導学会講演概要集 87th 31 2013.5

超電導磁気分離による常磁性ニッケル塩の回収

岡徹雄, 深澤晴信, 吉沢直人, 高柳優也, 小川純, 福井聡, 佐藤孝雄, 大泉学, 辻村盛夫, 横山和哉

電気学会全国大会講演論文集 2013 ( 6 ) 6.S7(8)-6.S7(10) 2013.3

ツイスト型高温超電導線材の適用による多層同軸型スパイラルケーブルの交流損失低減効果

大塚良介, 福井聡, 小川純, 岡徹雄, 佐藤孝雄, 大屋正義, 増田孝人

電気学会全国大会講演論文集 2013 ( 5 ) 261 - 262 2013.3

高温超伝導バルク磁石を用いた埋込構造永久磁石同期機の永久磁石の着磁

上原翔, 川崎信隆, 福井聡, 小川純, 佐藤孝雄, 岡徹雄, 横山和哉

電気学会全国大会講演論文集 2013 ( 5 ) 289 2013.3

大型風力用高温超電導同期発電機の電気設計

前澤勝, 福井聡, 小川純, 岡徹雄, 佐藤孝雄

電気学会全国大会講演論文集 2013 ( 5 ) 285 2013.3

傾斜巻線部の導入による高温超伝導コイルの交流損失低減効果

石井寛明, 塚本翔午, 中村航, 松田旺, 福井聡, 小川純, 佐藤孝雄, 塚本修巳

低温工学・超電導学会講演概要集 88th 2013

挿入された鉄心形状による高温超伝導線材の交流損失特性への影響

前川達也, 伏見侑, 小川純, 福井聡, 岡徹雄, 佐藤孝雄

低温工学・超電導学会講演概要集 86th 77 2012.11

Experiment and Numerical Analysis of a Magnetizing Technique for Permanent Magnets of IPM Motors using HTS Bulk Magnets

KAWASAKI Nobutaka, UEHARA Shou, FUKUI Satoshi, OGAWA Jun, SATO Takao, TERASAWA Toshihisa, YOKOYAMA Kazuya, OKA Tetsuo

TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 47 ( 9 ) 568 - 575 2012.9

Language：Japanese Publisher：CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

Intense magnetic fields exceeding 2 T are necessary to magnetize rare-earth magnets to extract the full performance of magnet materials. In this report, we deal with the experimental measurements and numerical analysis of the magnetic flux after scans of the 3 T HTS bulk magnet on the surface of the rare-earth magnet. The distributions of the magnetic flux density between measured and simulated data on the magnet slab showed good agreement after the scanning. The study is conducted to evaluate the magnetization performances of bulk magnets for the interior permanent magnet (IPM) motors. According to the numerical analysis, the magnetic field of 3 T reached the point of 22 mm from the surface of the rotor. The experimental data clarified that the magnet slab (26 × 20 × 5 mm<sup>3</sup>) in the rotor was fully magnetized by scanning the bulk magnet on it, while the neighboring magnet was barely magnetized in the rotor because of its anisotropic magnetizing property. This shows that the magnets in IPM motors are capable of being activated from outside the rotors with use of HTS bulk magnets, which suggests an improved degree of freedom in designing the motor.

DOI： 10.2221/jcsj.47.568

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