Local structure changes and structural transformations of melt, glass and gel under the Earth's mantle conditions.

地幔条件下熔体、玻璃和凝胶的局部结构变化和结构转变。

基本信息

项目摘要

Using a large-volume high-pressure apparatus, phases of crystals, melts, glasses and gel in the system of some germanates, fluorides, halogenides and silicates have been compressed up to 15 GPa at 300-1500K. The local structure changes around the specific kind of atom have been investigated by an in situ XAFS(x-ray absorption fine structure) method using synchrotron radiation. The structures have also been characterized by means of diffraction and spectroscopic methods. Dynamical atomic motion for each atom in these phases has been studied by determined Debye-Waller factors. The atomic effective pair potentials, the phonon energies and Gruneisen parameters have been estimated in this study. For example, the coordination number of Ge in GeO2 glass changes from four to six between 8 and 10 GPa. In contrast to the case for the glass, the coordination environment around Ge in GeO2 gel gradually increases over a pressure range from 2 to 12 GPa. Liquid germinate consisting of tetrahedrally coordinated Ge contracts with increasing pressure without significant changes in the local structure up to 2.5 GPa at 1300 K and then shows an abrupt fourfold-to-sixfold coordination change around 3 GPa. The coordination change is completed below 4 GPa where upon a high-density liquid consisting of octahedrally coordinated Ge becomes stable. By analogy with this liquid germanate, it is expected that a sharp transition occurs in liquid silicate at a higher pressure. Geophysical implications derived from this study will be discussed with detailed data of our studies.
用大体积高压装置,在300- 1500 K温度下,对锗酸盐、氟化物、卤化物和硅酸盐体系中的晶体、熔体、玻璃和凝胶相进行了压缩,压缩压力达15 GPa。利用同步辐射X射线吸收精细结构(XAFS)方法研究了特定原子周围的局域结构变化。结构也已通过衍射和光谱方法进行了表征。通过确定Debye-Waller因子,研究了这些相中每个原子的动力学运动。本文计算了原子的有效对势、声子能量和Gruneisen参数。例如,GeO 2玻璃中Ge的配位数在8 - 10 GPa之间从4变为6。与玻璃的情况相反,GeO 2凝胶中Ge周围的配位环境在2至12 GPa的压力范围内逐渐增加。由四面体配位的Ge组成的液体萌发物随着压力的增加而收缩,在1300 K时局部结构没有显着变化,直到2.5 GPa,然后在3 GPa附近显示出突然的四倍至六倍的配位变化。配位变化在4GPa以下完成,其中由八面体配位的Ge组成的高密度液体变得稳定。通过与这种液体锗酸盐类比,预期在较高压力下在液体硅酸盐中发生急剧转变。地球物理意义来自这项研究将讨论我们的研究的详细数据。

项目成果

期刊论文数量(53)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
A.Yoshiasa, M.Okube 他: "XAFS study of A-site-deficient La0. 63Ti0. 92Nb0. 0803 perovskite"Physica Scripta. (accepted).
A. Yoshiasa、M. Okube 等人:“A 位缺陷 La0.63Ti0.92Nb0.0803 钙钛矿的 XAFS 研究”Physica Scripta(已接受)。
  • DOI:
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    0
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Single crystal X-ray diffraction study of the vanadate garnet Ca2NaZn2V3O12
  • DOI:
    10.1016/j.materresbull.2004.03.013
  • 发表时间:
    2004-06
  • 期刊:
  • 影响因子:
    5.4
  • 作者:
    A. Nakatsuka;Y. Ikuta;A. Yoshiasa;K. Iishi
  • 通讯作者:
    A. Nakatsuka;Y. Ikuta;A. Yoshiasa;K. Iishi
Graphite-hexagonal diamond transition and surviving compressed graphite.
石墨-六方金刚石转变和幸存的压缩石墨。
Detailed Structures of Hexagonal Diamond (lonsdaleite) and Wurtzite-type BN
  • DOI:
    10.1143/jjap.42.1694
  • 发表时间:
    2003-04
  • 期刊:
  • 影响因子:
    1.5
  • 作者:
    A. Yoshiasa;Y. Murai;O. Ohtaka;T. Katsura
  • 通讯作者:
    A. Yoshiasa;Y. Murai;O. Ohtaka;T. Katsura
Electrical conductivities and conduction mechanisms of perovskite-type Na_<1-z>K_xMgF_3 (x=0,0.1,1) and KZnF_3.
钙钛矿型Na_<1-z>K_xMgF_3 (x=0,0.1,1)和KZnF_3的电导率和传导机制。
  • DOI:
  • 发表时间:
    2005
  • 期刊:
  • 影响因子:
    0
  • 作者:
    A.Yoshiasa;D.Sakamoto他
  • 通讯作者:
    D.Sakamoto他
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YOSHIASA Akira其他文献

YOSHIASA Akira的其他文献

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{{ truncateString('YOSHIASA Akira', 18)}}的其他基金

Japanese leading local structure study on minerals and melts under shock compression and high-temperature and -pressure
日本领先的冲击压缩和高温高压下矿物和熔体的局部结构研究
  • 批准号:
    22244068
  • 财政年份:
    2010
  • 资助金额:
    $ 2.3万
  • 项目类别:
    Grant-in-Aid for Scientific Research (A)
Decipherment of important reoord concerning the earth and planet activity that remains in local structure of trace elements
破译保留在微量元素局部结构中的有关地球和行星活动的重要记录
  • 批准号:
    17204049
  • 财政年份:
    2005
  • 资助金额:
    $ 2.3万
  • 项目类别:
    Grant-in-Aid for Scientific Research (A)
Local structures and electoric conduction mechanism of minerals in Earth's lower mantle.
地球下地幔矿物的局部结构和导电机制。
  • 批准号:
    11640479
  • 财政年份:
    1999
  • 资助金额:
    $ 2.3万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Observation and Simulation of atomic motion in the Eath internal materials
地球内部材料中原子运动的观测与模拟
  • 批准号:
    09640570
  • 财政年份:
    1997
  • 资助金额:
    $ 2.3万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)

相似海外基金

Electrical conductivity measurements of silicate melts at the Earth's mantle conditions
地幔条件下硅酸盐熔体的电导率测量
  • 批准号:
    24K17146
  • 财政年份:
    2024
  • 资助金额:
    $ 2.3万
  • 项目类别:
    Grant-in-Aid for Early-Career Scientists
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