The compressional sound velocity vp for enstitate of polycrystalline specimens was measured at pressures from 40 to 140 GPa by using the optical analyzer techniques under shock loading. The dependence of vp (in units ...The compressional sound velocity vp for enstitate of polycrystalline specimens was measured at pressures from 40 to 140 GPa by using the optical analyzer techniques under shock loading. The dependence of vp (in units of km/s) on Hugoniot pressure p (in units of GPa) can be described by: vp = 3.079 - 0.691 lnp + 0.0941n2p. The vp satisfies Birch's law: vp = 6.213 + 1.212 ρ, where ρ is corresponding density, indicating that enstatite is stable throughout the conditions of the lower mantle. Here P wave velocity is 0.5% lower and S wave velocity is 2% higher than those of preliminary reference earth model, respectively. It is concluded that the lower mantle is mainly composed of perovskite-(Mg1-x,Fex)SiO3 and only small amount of (Mg1-x,Fex)O is allowed in it.展开更多
By using two oxygen specific electrolyte discs and applying a dc voltage between the sample and an oxygen buffer,oxygen can be driven into or pumped from the sample at a fixed temperature and pressure.By measuring the...By using two oxygen specific electrolyte discs and applying a dc voltage between the sample and an oxygen buffer,oxygen can be driven into or pumped from the sample at a fixed temperature and pressure.By measuring the voltage between the sample and a reference buffer,the oxygen fugacity in the sample is simultaneously monitored.Therefore,the oxygen fugacity in the sample at high temperature and high pressure can be in situ controlled independently of temperature and pressure.展开更多
基金the National Natural Science Foundation of China under Grant No.19672058the Science and Technology Foundation of Chinese Academy of Engineering Physics under Grant No.960103.
文摘The compressional sound velocity vp for enstitate of polycrystalline specimens was measured at pressures from 40 to 140 GPa by using the optical analyzer techniques under shock loading. The dependence of vp (in units of km/s) on Hugoniot pressure p (in units of GPa) can be described by: vp = 3.079 - 0.691 lnp + 0.0941n2p. The vp satisfies Birch's law: vp = 6.213 + 1.212 ρ, where ρ is corresponding density, indicating that enstatite is stable throughout the conditions of the lower mantle. Here P wave velocity is 0.5% lower and S wave velocity is 2% higher than those of preliminary reference earth model, respectively. It is concluded that the lower mantle is mainly composed of perovskite-(Mg1-x,Fex)SiO3 and only small amount of (Mg1-x,Fex)O is allowed in it.
基金Supported by the National Natural Science Foundation of China under Grant No.49674221the National Science Council under NSC-86-2111-M-001-021,Taipei.
文摘By using two oxygen specific electrolyte discs and applying a dc voltage between the sample and an oxygen buffer,oxygen can be driven into or pumped from the sample at a fixed temperature and pressure.By measuring the voltage between the sample and a reference buffer,the oxygen fugacity in the sample is simultaneously monitored.Therefore,the oxygen fugacity in the sample at high temperature and high pressure can be in situ controlled independently of temperature and pressure.
