Search Results - "Hirao, Naohisa"

A perovskitic lower mantle inferred from high-pressure, high-temperature sound velocity data by Murakami, Motohiko, Ohishi, Yasuo, Hirao, Naohisa, Hirose, Kei

“…Determination of the shear-wave velocities for silicate perovskite and ferropericlase under the pressure and temperature conditions of the deep lower mantle…”
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Crystal structure of the superconducting phase of sulfur hydride by Einaga, Mari, Sakata, Masafumi, Ishikawa, Takahiro, Shimizu, Katsuya, Eremets, Mikhail I., Drozdov, Alexander P., Troyan, Ivan A., Hirao, Naohisa, Ohishi, Yasuo

“…The discovery of a superconducting temperature of roughly 200 K in hydrogen sulfide has attracted widespread attention. Now, the crystal structure of this…”
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Elastic softening of bulk modulus of monoclinic HfO2 under high pressure by Akahama, Yuichi, Kawaguchi, Saori, Hirao, Naohisa, Ohishi, Yasuo

“…In this study, the lattice compression properties of monoclinic HfO2 (m-HfO2) at room temperature are investigated by performing high-pressure powder x-ray…”
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Equation of State of Liquid Iron under Extreme Conditions by Kuwayama, Yasuhiro, Morard, Guillaume, Nakajima, Yoichi, Hirose, Kei, Baron, Alfred Q R, Kawaguchi, Saori I, Tsuchiya, Taku, Ishikawa, Daisuke, Hirao, Naohisa, Ohishi, Yasuo

“…The density of liquid iron has been determined up to 116 GPa and 4350 K via static compression experiments following an innovative analysis of diffuse…”
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Stability of hydrous phase H MgSiO4H2 under lower mantle conditions by Ohtani, Eiji, Amaike, Yohei, Kamada, Seiji, Sakamaki, Tatsuya, Hirao, Naohisa

“…We report the stability field of a new high‐pressure hydrous phase, phase H MgSiO4H2, and its implications for water transport into the deep lower mantle. We…”
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Incorporation mechanism of Fe and Al into bridgmanite in a subducting mid-ocean ridge basalt and its crystal chemistry by Nakatsuka, Akihiko, Fukui, Hiroshi, Kamada, Seiji, Hirao, Naohisa, Ohkawa, Makio, Sugiyama, Kazumasa, Yoshino, Takashi

“…The compositional difference between subducting slabs and their surrounding lower-mantle can yield the difference in incorporation mechanism of Fe and Al into…”
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Superconductivity of Pure H3S Synthesized from Elemental Sulfur and Hydrogen by Nakao, Harushige, Einaga, Mari, Sakata, Masafumi, Kitagaki, Masaomi, Shimizu, Katsuya, Kawaguchi, Saori, Hirao, Naohisa, Ohishi, Yasuo

“…In this study, we performed electrical resistance measurements for a superconductive H3S synthesized from elemental sulfur and hydrogen (2S + 3H2 → 2H3S). The…”
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Diamond formation in the deep lower mantle: a high-pressure reaction of MgCO3 and SiO2 by Maeda, Fumiya, Ohtani, Eiji, Kamada, Seiji, Sakamaki, Tatsuya, Hirao, Naohisa, Ohishi, Yasuo

“…Diamond is an evidence for carbon existing in the deep Earth. Some diamonds are considered to have originated at various depth ranges from the mantle…”
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Two-phase mixture of iron–nickel–silicon alloys in the Earth’s inner core by Ikuta, Daijo, Ohtani, Eiji, Hirao, Naohisa

“…Abstract The Earth’s inner core comprises iron-nickel alloys with light elements. However, there is no clarity on the phase properties of these alloys. Here we…”
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The electrical conductivity of Fe4O5, Fe5O6, and Fe7O9 up to 60 GPa by Maitani, Shuhou, Sinmyo, Ryosuke, Ishii, Takayuki, Kawaguchi, Saori I., Hirao, Naohisa

“…The electrical conductivities of iron-bearing minerals are important for understanding the chemical and thermal heterogeneity of the Earth’s mantle. Recent…”
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Diamond formation from methane hydrate under the internal conditions of giant icy planets by Kadobayashi, Hirokazu, Ohnishi, Satoka, Ohfuji, Hiroaki, Yamamoto, Yoshitaka, Muraoka, Michihiro, Yoshida, Suguru, Hirao, Naohisa, Kawaguchi-Imada, Saori, Hirai, Hisako

“…Hydrocarbon chemistry in the C–O–H system at high pressure and high temperature is important for modelling the internal structure and evolution of giant icy…”
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Phase boundary of hot dense fluid hydrogen by Ohta, Kenji, Ichimaru, Kota, Einaga, Mari, Kawaguchi, Sho, Shimizu, Katsuya, Matsuoka, Takahiro, Hirao, Naohisa, Ohishi, Yasuo

“…We investigated the phase transformation of hot dense fluid hydrogen using static high-pressure laser-heating experiments in a laser-heated diamond anvil cell…”
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Experimental and theoretical thermal equations of state of MgSiO3 post-perovskite at multi-megabar pressures by Sakai, Takeshi, Dekura, Haruhiko, Hirao, Naohisa

“…The MgSiO 3 post-perovskite phase is the most abundant silicate phase in a super-Earth’s mantle, although it only exists within the Earth’s lowermost mantle…”
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Chemical Reactions Between Fe and H2O up to Megabar Pressures and Implications for Water Storage in the Earth's Mantle and Core by Yuan, Liang, Ohtani, Eiji, Ikuta, Daijo, Kamada, Seiji, Tsuchiya, Jun, Naohisa, Hirao, Ohishi, Yasuo, Suzuki, Akio

“…We investigated the phase relations of the Fe‐H2O system at high pressures based on in situ X‐ray diffraction experiments and first‐principles calculations and…”
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Equations of state of iron and nickel to the pressure at the center of the Earth by Hirao, Naohisa, Akahama, Yuichi, Ohishi, Yasuo

“…Synchrotron radiation x-ray diffraction investigations of iron (Fe) and nickel (Ni) are conducted at pressures up to 354 and 368 GPa, respectively, and the…”
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Stability field of the hcp-structure for Fe, Fe-Ni, and Fe-Ni-Si alloys up to 3 Mbar by Sakai, Takeshi, Ohtani, Eiji, Hirao, Naohisa, Ohishi, Yasuo

“…The phase relations of Fe, Fe90Ni10 and Fe87.9Ni4.4Si7.7 were investigated up to 273(6) GPa and 4490(560) K, 250(19) GPa and 2730(110) K and 304(3) GPa and…”
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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 by Sata, Nagayoshi, Hirose, Kei, Shen, Guoyin, Nakajima, Yoichi, Ohishi, Yasuo, Hirao, Naohisa

“…The light alloying element in the Earth's core has not been identified yet. Here we determined the pressure‐volume equations of state of FeSi, Fe3C, and…”
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Low-spin ferric iron in primordial bridgmanite crystallized from a deep magma ocean by Okuda, Yoshiyuki, Ohta, Kenji, Nishihara, Yu, Hirao, Naohisa, Wakamatsu, Tatsuya, Suehiro, Sho, Kawaguchi, Saori I., Ohishi, Yasuo

“…The crystallization of the magma ocean resulted in the present layered structure of the Earth’s mantle. An open question is the electronic spin state of iron…”
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Fe2S: The Most Fe‐Rich Iron Sulfide at the Earth's Inner Core Pressures by Tateno, Shigehiko, Ozawa, Haruka, Hirose, Kei, Suzuki, Toshihiro, I‐Kawaguchi, Saori, Hirao, Naohisa

“…We examined the phase relation of Fe2S to 306 GPa and 3,000 K and found that Fe2S forms an orthorhombic structure with space group Pnma above 190 GPa…”
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Discovery of coesite and stishovite in eucrite by Miyahara, Masaaki, Ohtani, Eiji, Yamaguchi, Akira, Ozawa, Shin, Sakai, Takeshi, Hirao, Naohisa

“…Howardite–eucrite–diogenite meteorites (HEDs) probably originated from the asteroid 4 Vesta. We investigated one eucrite, Béréba, to clarify a dynamic event…”
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