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Dobashi, Kunio*; Shimizu, Yasuo*; Matsuzaki, Shinichi*; Nagamine, Takeaki*; Sato, Takahiro; Okubo, Takeru; Yokoyama, Akihito; Ishii, Yasuyuki; Kamiya, Tomihiro; Arakawa, Kazuo*; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 87, 2012/01
conditions & electrical transport and structural properties of FeH
Matsuoka, Takehiro*; Hirao, Naohisa*; Oishi, Yasuo*; Shimizu, Katsuya*; Machida, Akihiko; Aoki, Katsutoshi
Koatsuryoku No Kagaku To Gijutsu, 21(3), p.190 - 196, 2011/09
We present the newly developed electrical resistance measurement technique for metal hydrides compressed in high-pressure H and the first successful 
simultaneous measurements of electrical resistance and X-ray diffraction of FeH at high pressures and low temperatures. The electrical resistivity 
showed a sharp increase with the formation of iron-hydride FeH (
) at 3.5 GPa. The 
'-phase of FeH was found to be metallic up to 25.5 GPa. The vs. 
curves up to 16.5 GPa approximately follow Fermi-liquid law below 25 K. However, 
was found to be better fitting at 25.5 GPa. This change can be related to the previously reported ferromagnetism collapse at corresponding pressures.
Matsuoka, Takahiro*; Fujihisa, Hiroshi*; Hirao, Naohisa*; Oishi, Yasuo*; Mitsui, Takaya; Masuda, Ryo; Seto, Makoto*; Yoda, Yoshitaka*; Shimizu, Katsuya*; Machida, Akihiko; et al.
Physical Review Letters, 107(2), p.025501_1 - 025501_4, 2011/07
Times Cited Count：28 Percentile：77.59(Physics, Multidisciplinary)Europium-hydride EuH
exposed to high-pressure H conditions has been found to exhibit structural and valence changes, 
(
=2, divalent) 
63/
(=2, 7.2-8.7 GPa) 
4/
(
2, 8.7-9.7 GPa) 4/
(2, 9.7 GPa-, trivalent). Having trivalent character and distorted cubic fcc structure, the 4/ structure is the 
-phase which has been commonly observed for other rare-earth metal hydrides. Our study clearly demonstrates that EuH is no longer an "irregular" member of the rare earth metal hydrides.
Matsuzaki, Shinichi*; Shimizu, Yasuo*; Dobashi, Kunio*; Nagamine, Takeaki*; Sato, Takahiro; Okubo, Takeru; Yokoyama, Akihito; Ishii, Yasuyuki; Kamiya, Tomihiro; Arakawa, Kazuo*; et al.
International Journal of Immunopathology and Pharmacology, 23(1), p.1 - 11, 2010/01
(
3) under high pressureMatsuoka, Takehiro*; Kitayama, Takayasu*; Shimizu, Katsuya*; Nakamoto, Yuki*; Kagayama, Tomoko*; Aoki, Katsutoshi; Oishi, Yasuo*; Takemura, Kenichi*
High Pressure Research, 26(4), p.391 - 394, 2006/12
Times Cited Count：3 Percentile：26.57(Physics, Multidisciplinary)The electrical and structural properties of yttrium hydride YHx was studied by the in-situ measurements of the electrical resistance and X-ray diffraction up to 86 GPa. The electrical resistivity increased with applying pressure up to 10 GPa and showed a maximum which accompanied with the structural transition of metal lattice from hcp to fcc structure. In fcc phase the resistivity decreased significantly, however the value still remained larger by 4 orders of magnitude that that of pure yttrium metal. We could not confirm the insulator to metal transition up to 23 GPa. The resistivity showed another maximum in the large pressure region 40 60 GPa without the structural phase transition of metal lattice.
Shimizu, Yasuo*; Dobashi, Kunio*; Kusakabe, Takahiko*; Nagamine, Takeaki*; Oikawa, Masakazu*; Sato, Takahiro; Haga, Junji*; Okubo, Takeru; Ishii, Yasuyuki; Kamiya, Tomihiro; et al.
no journal, ,
no abstracts in English
Shimizu, Yasuo*; Matsuzaki, Shinichi*; Sato, Takahiro; Kamiya, Tomihiro; Okubo, Takeru; Ishii, Yasuyuki; Arakawa, Kazuo*; Nagamine, Takeaki*; Dobashi, Kunio*
no journal, ,
no abstracts in English
Matsuoka, Takehiro*; Shimizu, Katsuya*; Fujihisa, Hiroshi*; Hirao, Naohisa*; Oishi, Yasuo*; Yoda, Yoshitaka*; Mitsui, Takaya; Masuda, Ryo; Machida, Akihiko; Aoki, Katsutoshi; et al.
no journal, ,
Europium-hydride EuH exposed to high-pressure H conditions has been studied by X-ray diffraction and M
ssbauer spectroscopy measurements up to 50 GPa using synchrotron radiation. We report new structural and valence transitions, Pnma(x=2, divalent) P63/mmc(x=2, 7.2-8.7GPa) I4/m(x2, 8.7-9.7 GPa) I4/mmm(x2, 9.7 GPa, trivalent). The phase of I4/mmm having trivalent character is a small distortion from cubic fcc structure which has been commonly observed for -phase of all other trivalent rare-earth metal hydrides. Our study clearly demonstrates the first observation of -phase of EuH and suggest that the material is no longer an irregular member of the rare earth metal hydrides RH systems.
Sato, Takahiro; Koka, Masashi; Kozai, Naofumi; Shimizu, Yasuo*; Dobashi, Kunio*; Kada, Wataru; Yokoyama, Akihito; Okubo, Takeru; Yamazaki, Akiyoshi; Ishii, Yasuyuki; et al.
no journal, ,
In the ML-EM for PIXE-CT, energy loss of incident particles and absorption of X-rays affect must be estimated using STIM-CT. This paper shows the appropriateness and the expected spatial resolution of this method are evaluated by a computer simulation and some practical experiments using 3 MeV proton microbeam with a diameter of 1
m at TIARA. The PIXE-CT experiments were carried out using a dried unicellulate and human lung tissue as a test sample placed on an automatic rotation stage, which made a full turn by rotating 360
at each step of 18 in vacuum. In the simulation, X-ray yield and absorption were calculated using density distribution of two-dimensional Shepp phantom. The results of those simulation and experiments have proved that this method is effective in PIXE-CT.
Dobashi, Kunio*; Shimizu, Yasuo*; Matsuzaki, Shinichi*; Ishizuka, Tamotsu*; Mori, Masatomo*; Sato, Takahiro; Koka, Masashi; Yokoyama, Akihito; Okubo, Takeru; Ishii, Yasuyuki; et al.
no journal, ,
no abstracts in English
Shimizu, Yasuo*; Matsuzaki, Shinichi*; Dobashi, Kunio*; Mori, Masatomo*; Sato, Takahiro; Koka, Masashi; Yokoyama, Akihito; Okubo, Takeru; Ishii, Yasuyuki; Kamiya, Tomihiro
no journal, ,
no abstracts in English
