Yoshihiro Nishisu
National Institute of Advanced Industrial Science and Technology
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Publication
Featured researches published by Yoshihiro Nishisu.
Journal of Non-crystalline Solids | 2003
Masanori Tanaka; Yoshihiro Nishisu; Mikio Kobayashi; Atusi Kurita; Hiromasa Hanzawa; Yasuo Kanematsu
Abstract Spherical fine particles of glassy Eu3+ doped yttrium basic carbonate, whose sizes are about 300 nm in diameter, are prepared by a co-precipitation method using urea as a precipitation generator. The optical properties concerned with the f–f transitions of Eu3+ are investigated for the as-prepared powder and the powder samples calcined at 300 and 550 °C. As the calcination temperature becomes high, the absorption band (charge-transfer band) due to the electron transfer from O2− to Eu3+ shifts to lower energy. The forced electric dipole 5 D 0 – 7 F J (J=0,2,3,4) transition strengths and the inhomogeneous width of the 5D0–7F0 luminescence spectrum of Eu3+ increase with calcination temperature. From these results, the local structure around Eu3+ is compared among the three powder samples. The persistent spectral hole burning (PSHB) effect is observed at 10, 70, and 120 K in the 7F0–5D0 transition of Eu3+ in all the samples. It is found that, at these temperatures, the burning reaction rate decreases with increasing calcination temperature. Probable PSHB mechanisms of the three samples are discussed.
Shigen-to-sozai | 1999
Yoshihiro Nishisu; Mikio Kobayashi
Fine composite particles containing yttrium and iron were prepared from homogeneous solution using urea as a precipitant generator. The ratio of yttrium to iron in the precipitate could be controlled by adjusting the concentration of the starting materials in the initial solution. These composite particles were considered to be amorphous. Shapes and morphology of the precipitated particles were influenced by the difference of the reaction conditions. Particles obtained from the solution containing 1.88 mmol dm-3 FeCl3 H2O, 3.13 mmol dm-3 YCl3 H2O and 500 mmol dm-3 urea at 97 °C were almost spherical and mono-dispersed. Particles precipitated on the condition as mentioned above converted from amorphous into monophasic garnet (Y3Fe5O12) by calcining at 1,200 °C for 5 hours. After calcination, particle changed its color from brown to medium olive and indicated marked magnetic character.
Archive | 1994
Yoshihiro Nishisu; Mikio Kobayashi
The Mining and Materials Processing Institute of Japan | 1995
Yoshihiro Nishisu; Mikio Kobayashi
Journal of Alloys and Compounds | 2006
Yoshihiro Nishisu; Mikio Kobayashi; Hitoshi Ohya; Toshiyuki Akiya
Archive | 1993
Mikio Kobayashi; Yoshihiro Nishisu; 幹男 小林; 佳宏 西須
Archive | 2002
Mikio Kobayashi; Susumu Miyazaki; Yoshihiro Nishisu; Keiji Ono; 慶司 大野; 進 宮崎; 幹男 小林; 佳宏 西須
Shigen-to-sozai | 1999
Yoshihiro Nishisu; Mikio Kobayashi
Archive | 2002
Takayoshi Kaihara; Mikio Kobayashi; Susumu Miyazaki; Yoshihiro Nishisu; Keiji Ono; 慶司 大野; 進 宮崎; 幹男 小林; 隆義 槐原; 佳宏 西須
Archive | 2001
Mikio Kobayashi; Susumu Miyazaki; Yoshihiro Nishisu; 進 宮崎; 幹男 小林; 佳宏 西須
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National Institute of Advanced Industrial Science and Technology
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