| Project/Area Number |
21740374
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Tohoku University |
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Principal Investigator |
SAKAI Takeshi 東北大学, 国際高等研究教育機構, 助教 (90451616)
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| Project Period (FY) |
2009 – 2010
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| Project Status |
Completed (Fiscal Year 2010)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2010: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2009: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | 地殻 / マントル / 核 / 地球中心核 / 高温高圧 / 圧力スケール / ダイヤモンドアンビルセル |
|---|
| Research Abstract |
We compressed NaCl-B2 to 304 Gpa and presented a pressure scale based on the Birch-Murnaghan and Vinet equations of state for this phase. The phase relations of Fe, Fe_<90>Ni_<10> and Fe_<87.9>Ni_<4.4>Si_<7.7> were investigated up to 273(6) Gpa and 4490(560) K, 250(19) Gpa and 2730(110) K and 304(3) Gpa and 2780(210) K, respectively, and the hexagonal close-packed structure was found to be stable in all of these compounds under the pressure and temperature conditions studied. The weak temperature dependency of the axial ratio of hcp-Fe-Ni-Si alloy indicates that the c-axis is still harder than the a-axis at high temperature condition. Therefore the alignment of hcp-Fe-Ni-Si alloy with the c-axis parallel to the Earth's rotation axis could account for the observation of the seismic wave anistropy of the inner core. On the other hand, Fe_<88.1>Ni_<9.1>S_<2.8> alloy was compressed up to 335 Gpa, and the hexagonal close-packed structure was found to be stable. Our results indicate that the hcp Fe-5 at.% Ni-7.9-10.3 at.% S alloy can account for the density of the inner core at 330 Gpa, assuming a linear relationship exists between the density and the nickel and sulfur content.
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