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Naohisa Hirao
Researcher at Tohoku University
Publications - 193
Citations - 4555
Naohisa Hirao is an academic researcher from Tohoku University. The author has contributed to research in topics: Diamond anvil cell & Phase (matter). The author has an hindex of 35, co-authored 179 publications receiving 3678 citations. Previous affiliations of Naohisa Hirao include National Institute for Materials Science.
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Journal ArticleDOI
Crystal structure of the superconducting phase of sulfur hydride
Mari Einaga,Masafumi Sakata,Takahiro Ishikawa,Katsuya Shimizu,Mikhail Eremets,A. P. Drozdov,I. A. Troyan,Naohisa Hirao,Yasuo Ohishi +8 more
TL;DR: The crystal structure of the superconducting phase of hydrogen sulfide (and deuterium sulfide) in the normal andsuperconducting states obtained by means of synchrotron X-ray diffraction measurements, combined with electrical resistance measurements at both room and low temperatures are reported.
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A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data
TL;DR: The mineralogical model that provides the best fit to a global seismic velocity profile indicates that perovskite constitutes more than 93 per cent by volume of the lower mantle, which is a much higher proportion than that predicted by the conventional peridotitic mantle model.
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Highly intense monochromatic X-ray diffraction facility for high-pressure research at SPring-8
TL;DR: In this article, the beamline BL10XU at SPring-8, designed for X-ray diffraction experiments using diamond anvil cells at high pressure and low/high temperature, is continuously upgraded.
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Stability of a hydrous δ-phase, AlOOH–MgSiO2(OH)2, and a mechanism for water transport into the base of lower mantle
Itaru Ohira,Eiji Ohtani,Eiji Ohtani,Takeshi Sakai,Takeshi Sakai,Masaaki Miyahara,Naohisa Hirao,Yasuo Ohishi,Masahiko Nishijima +8 more
TL;DR: In this article, a new reaction between aluminous perovskite and water was reported to form alumina-depleted perovsite and hydrous δ-phase AlOOH-MgSiO2(OH)2 along the mantle geotherm in the lower mantle.
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Compression of FeSi, Fe3C, Fe0.95O, and FeS under the core pressures and implication for light element in the Earth's core
Nagayoshi Sata,Nagayoshi Sata,Kei Hirose,Kei Hirose,Guoyin Shen,Guoyin Shen,Yoichi Nakajima,Yasuo Ohishi,Naohisa Hirao +8 more
TL;DR: In this article, the authors determined the pressure-volume equations of state of FeSi, Fe3C, and Fe0.95O in the core pressure range by a combination of diamond-anvil cell and synchrotron X-ray diffraction techniques.