Faculty Profiles - TODA Kenji

セルフラックス法による真空紫外励起蛍光体の合成 Reviewed

稲田直樹, 戸田健司, 上松和義, 佐藤峰夫, 西須佳宏, 小林幹男

Journal of Ecotechnology Research 9 143 - 147 2003.12

Characterization of Phosphors in the Eu-doped Sr-Al-B-O system Reviewed

MIYOSHI Jun-ichi, TODA Kenji, UEMATSU Kazuyoshi, SATO Mineo, NISHISU Yoshihiro, KOBAYASHI Mikio

J.Ecotech.Res 9 ( 2 ) 137 - 142 2003.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：International Association of Ecotechnology Research

Phosphor materials have been searched in the Sr-Al-B-O system. For a molar ratio (Sr1-xEux) : Al : B = 1 : 2 : 2 (x = 0.01), a crystalline layered compound SrAl2B2O7：Eu2+ was synthesized at 900 °C for 12 h in a reductive atmosphere. The SrAl2B2O7:Eu2+ showed blue emission under UV (254 nm) and VUV (Vacuum Ultraviolet, 146 nm) excitation. For the ratio (Sr1-xEux) : Al : B = 2 : 2 : 2 (x = 0.01), a transparent glass and SrAl2O4 component with a long afterglow phosphorescence was found.

DOI： 10.11190/jer.9.137

CiNii Article

CiNii Books

Other Link： https://jlc.jst.go.jp/DN/JLC/20007068193?from=CiNii

Research and Characterization of the Phosphor for Mercury-free Fluorescent Lamps Reviewed

K. Toda, Y. Imanari, T. Nonogawa, K. Uematsu, M. Sato

Transactions of the Materials Research Society of Japan 28 1247 - 1250 2003.12

Synthesis of KNbO3 in Water Reviewed

K. Toda, S. Tokuoka, N. Ohtake, K. Uematsu, M. Sato

Transactions of the Materials Research Society of Japan 28 353 - 356 2003.12

Reaction Mechanism of Perovskite KNbO3 in Aqueous Solution Reviewed

K. Toda, S. Tokuoka, N. Ohtake, K. Uematsu, M. Sato

Key Engineering Materials 248 27 - 30 2003.12

Low Temperature Synthesis of Titanium oxide Reviewed

K. Toda, M. Kawakami, K. Uematsu, M. Sato

Transactions of the Materials Research Society of Japan 28 313 - 316 2003.12

Low Temperature Synthesis of Titania and Titanates Reviewed

K. Toda, M. Kawakami, K. Uematsu, M. Sato

Key Engineering Materials 248 107 - 110 2003.12

Green VUV phosphor with spinel structure, Mg1-xZnxAl2-yGayO4:Mn Reviewed

K. Toda, Y. Imanari, R. Arai, K. Uematsu, M. Sato, K. Ohno, S. Miyazaki

Journal of Materials Science Letters 22 ( 13 ) 979 - 980 2003.7

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

A green-emitting vacuum ultraviolet (VUV) phosphor, Mg1-xZnxal2-y-gayO4:Mn was synthesized by the conventional solid state reaction. The composition, Mg0.88Zn0.10Mn0.02Al2O4, shows the highest brightness under VUV excitation, which corresponds to about 13 times higher than that of sodium salicylate as a reference material.

DOI： 10.1023/A:1024621214914

New VUV phosphor, NaLnGeO4:Eu3+ (Ln = rare earth) Reviewed

Kenji Toda, Yu-Ichiro Imanari, Takashi Nonogawa, Kazuyoshi Uematsu, Mineo Sato

Chemistry Letters 32 ( 4 ) 346 - 347 2003.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Society of Japan

The synthesis and luminescence properties of Eu3+-doped ordered olivine-type NaLnGeO4 (Ln = rare earth) phosphors are reported. Under vacuum-UV (VUV) excitation, this phosphor showed intense red emission due to the 5D0-7F2 transition. The Na(Y0.3Gd0.65Eu0.05)GeO4 phosphor with optimum composition and synthetic condition under 147 nm excitation were higher than those of (Y0.95Eu0.05)2O3.

DOI： 10.1246/cl.2003.346

Synthesis of phosphor materials using natural ore "serpentine" Reviewed

Yu-Ichiro Imanari, Takashi Nonogawa, Jun-Ichi Miyoshi, Kenji Toda, Kazuyoshi Uematsu, Mineo Sato, Katsunori Kosuge, Yoshihiro Nishisu, Mikio Kobayashi

Journal of the Ceramic Society of Japan 111 ( 1290 ) 151 - 154 2003

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Ceramic Society of Japan

Serpentine is a hydrated ultra-mafic rock, which is primarily composed of magnesium silicate minerals such as chrysotile and antigorite. Fibrous chrysotile is the most common type of asbestos. Since the rich mines supplied serpentine in Japan, application of natural ore "serpentine" as raw materials for ceramics has one of the potentially lowest cost ceramics production. In this study, long afterglow phosphor, Sr2MgSi2O7, has been successfully synthesized using natural ore serpentinite. Eu2+ and Dy3+ co-doped compounds show long-lasting phosphorescence. This demonstrates that the "serpentine" could be used in preparing alkaline earth silicate phosphors.

DOI： 10.2109/jcersj.111.151

層状ペロブスカイトの光触媒特性 Reviewed

川上正人, 辻由浩, 清水研一, 上松和義, 戸田健司, 佐藤峰夫, 北山淑江

Journal of Ecotechnology Research 8 47 - 52 2002.12

Search for new vacuum-UV phosphors Reviewed

K. Toda, K. Uematsu, Y. Imanari, T. Nonogawa, M. Sato

Ceramic Engineering and Science Proceedings 23 861 - 868 2002.12

Room temperature synthesis and characterization of perovskite compounds Reviewed

K Toda, S Tokuoka, K Uematsu, M Sato

SOLID STATE IONICS 154 393 - 398 2002.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

A new soft chemical method has been developed to remove the rock-salt type layers in the Ruddlesden-Popper-type layered perovskite at room temperature. The rock-salt type (KF) blocks in the layered perovskite, K2NbO3F, were selectively dissolved into water to give three-dimensional perovskite, KNbO3, at room temperature. In the alkali metal aqueous solution, the ion-exchange reaction of parent layered compound with coexisting ions in the alkaline solution results in the new perovskites containing the other metal ions for the A-site. The development of this synthetic route could lead to interesting new metastable perovskite materials at low temperature. (C) 2002 Published by Elsevier Science B.V.

DOI： 10.1016/S0167-2738(02)00578-7

Preparation of iron phosphate cathode material of Li3Fe2(PO4)(3) by hydrothermal reaction and thermal decomposition processes Reviewed

M Sato, S Tajimi, H Okawa, K Uematsu, K Toda

SOLID STATE IONICS 152 247 - 251 2002.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Well-crystallized Li3Fe2(PO4)(3) with an orthorhombic beta-Fe-2(SO4)(3)-type structure was able to be synthesized by using two synthetic routes, where hydrothermal reaction and successive heat treatment with relatively low temperatures were employed. The samples prepared were found to show orthorhombic symmetry, contrary to the fact that a conventional solid state synthesis heating at temperatures higher than 1000 degreesC usually gives monoclinic symmetry. The sample showed two plateau potentials of 2.8 and 2.7 V vs. Li/Li+ upon discharge, and the total discharge capacity of the sample exhibited more than 80 mA h g(-1) under 0.5 mA cm(-2). (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0167-2738(02)00306-5

Synthesis and characterization of Perovskite-type ionic conductor: Li3yLa1-3y(Nb1-xWx)3O9 Reviewed

Y. Aoyama, A. Komeno, K. Toda, M. Sato

Key Engineering Materials 216 135 - 140 2002.12

New synthetic route of perovskite materials in the test tube Reviewed

K. Toda, K. Uematsu, N. Ohtake, S. Tokuoka, M. Sato

Ceramic Engineering and Science Proceedings 23 689 - 694 2002.12

Photocatalytic water splitting over spontaneously hydrated layered tantalate A2SrTa2O7·nH2O (A=H, K, Rb) Reviewed

Ken-Ichi Shimizu, Yoshihiro Tsuji, Masato Kawakami, Kenji Toda, Tatsuya Kodama, Mineo Sato, Yoshie Kitayama

Chemistry Letters ( 11 ) 1158 - 1159 2002.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Society of Japan

A series of layered perovskite-type tantalates with hydrated interlayer space, A2SrTa2O7·nH2O (A=H, K, Rb), exhibited efficient photocatalytic activity for water splitting into H2/O2 mixture under UV irradiation without loading metal co-catalysts.

DOI： 10.1246/cl.2002.1158

Characterization of potassium niobate produced by self-assembled nanosheet from aqueous solution Reviewed

K Toda, N Ohtake, M Kawakami, S Tokuoka, K Uematsu, M Sato

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 41 ( 11B ) 7021 - 7024 2002.11

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN SOC APPLIED PHYSICS

Submicron particles of potassium niobate KNbO3 were prepared by a colloid chemistry method. A rock-salt-type KF block in a layered perovskite, K2NbO3F, with a K2NiF4 type structure was selectively dissolved in water to produce perovskite nanosheets at room temperature. The self-assembly between perovskite nanosheets in a colloidal solution may enable shape control of potassium niobate powder. The microstructure, phase transition and mechanism of the solution process were investigated by transmission electron microscopy, X-ray diffraction and determination of ultraviolet-visible absorption spectra. [DOI: 10.1143/JJAP.41.7021].

DOI： 10.1143/JJAP.41.7021

Synthesis and characterization of new long persistent phosphor Reviewed

K Toda, Y Imanari, T Nonogawa, J Miyoshi, K Uematsu, M Sato

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 110 ( 4 ) 283 - 288 2002.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

Rare earth-doped alkaline earth silicates, Sr2MgSi2O7:Eu2+, Dy3+ and Ca2MgSi2O7: Eu2+, Dy3+, with an akermanite-type structure show bright and long-lasting phosphorescence. After irradiation by a white-color fluorescent lamp (780 lm) for 5 min, the light blue emission of Sr2MgSi2O7: Eu2+, Dy3+ was observable by naked eye in the dark for over 100 min after removal of the excitation light source.

DOI： 10.2109/jcersj.110.283