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FeH
under high pressure and high temperatureSaito, Hiroyuki; Takagi, Shigeyuki*; Matsuo, Motoaki*; Iijima, Yuki*; Endo, Naruki*; Aoki, Katsutoshi*; Orimo, Shinichi*
no journal, ,
no abstracts in English
Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*
no journal, ,
SiO
glass is an amorphous solid consisting of SiO tetrahedra. Each tetrahedra are connected to each other, and forms the many-menbered ring. Thus, the glass has large void space and therefore marked densification is expected under pressure. Actually, the density increases by 20% on compression to 8 GPa, accompanying the change in the intermediate range order. The density goes back to the original one on room-temperature decompression, but the high-density state is maintained once the sample is heated under pressure by structural relaxation (permanent densification). So far, the mechanism has been investigated, but remains to be revealed. To reveal the mechanism, in situ high-pressure diffraction is indispensable. Such data were obtained up to 10 GPa at the high-pressure neutron diffactometer PLANET in the last year, therefore we developed the method to analyze the data this year. By developing the program, we succeeded in obtaining structure factor and confirmed its reliability by comparing with the previous results.
Katayama, Yoshinori; Hattori, Takanori; Yagafarov, O.*; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Chiba, Ayano*; Otomo, Toshiya*
no journal, ,
Liquid water at ambient conditions has an ice-like, characteristic structure due to the hydrogen bonds between molecules. To study pressure and temperature dependence of the structure of water, we have carried out in-situ high-temperature high-pressure measurements on liquid water by in-situ synchrtorn X-ray diffraction experiments at the SPring-8 and molecular dynamics simulations. The results revealed transformation from the ice-like structure to a simple-liquid-like structure. To investigate change in hydrogen bonds, neutron is an important probe. We carried out neturon diffraction measurements on heavy water at 100
C and 200C at 2 GPa using high-pressure diffractometer, PLANET, at J-PARC/MLF. Significant temperature dependence of width of first peak in diffraction pattern, which is similar to that observed in the previous neutron diffraction experiments at 0.8 GPa.
Osakabe, Toyotaka; Kato, Yoshihiro*; Kuwahara, Keitaro*
no journal, ,
no abstracts in English
Sano, Asami; Hattori, Takanori; Funakoshi, Kenichi*; Abe, Jun*; Machida, Shinichi*
no journal, ,
The 6-6 type cell has been used successfully in the 6-axis multi-anvil press (ATSUHIME), but the available PT-conditions were limited to below 10 GPa and 2000 K. To extend the accessible PT-conditions, we applied a 6-8 type cell to ATSUHIME. The cell consists of eight second-stage anvils, gaskets and a furnace assembly. The cubes of sintered diamond with truncated edge length (TEL) of 5 mm were used as the second stage anvils. The sample is in the internal heater in the furnace assembly. The volume of the sample is 6 mm
before the compression. The performance evaluation test of 6-8 cell was conducted using NaCl as an internal standard. The pressure was determined to be 16 GPa at 1600 kN by the equation of state of NaCl. Heating test was also conducted up to 1000
C at 1600 kN. The pressure decreased slightly during the heating; 14 GPa at 800C.
under high pressureMachida, Akihiko; Watanuki, Tetsu; Hattori, Takanori; Sano, Asami; Yagafarov, O.*; Katayama, Yoshinori; Aoki, Katsutoshi; Oshita, Hidetoshi*; Ikeda, Kazutaka*; Otomo, Toshiya*
no journal, ,
no abstracts in English
Watanuki, Tetsu; Mizumaki, Masaichiro*; Kim, H.*; Yu, R.*; Machida, Akihiko; Sakaki, Koji*; Nakamura, Yumiko*; Oka, Kengo*; Azuma, Masaki*
no journal, ,
no abstracts in English