A transmission-reflection-combined new method is presented for measuring elastic velocities of rocks and minerals at elevated temperature and pressure,which resolves the problems of gradients of temperature and pressu...A transmission-reflection-combined new method is presented for measuring elastic velocities of rocks and minerals at elevated temperature and pressure,which resolves the problems of gradients of temperature and pressure existing in original sample assembly with a pyrophyllite cube.At room temperature and pressure up to 3 GPa,single-crystal quartz and eclogite were used to provide samples under test,respectively.The results of this work agree with the previous measurements very well within the error range.By the use of this new technique,more precise and reasonable data of elastic properties of rocks and minerals at elevated temperature and pressure can be achieved.展开更多
By in situ x-ray diffraction,an isostructural phase transition between two kinds of the cubic PbCrO_(3) perovskites at around 1.6 GPa and room temperature with a 9.8%volume change is discovered.Recently,we have synthe...By in situ x-ray diffraction,an isostructural phase transition between two kinds of the cubic PbCrO_(3) perovskites at around 1.6 GPa and room temperature with a 9.8%volume change is discovered.Recently,we have synthesized this cubic PbCrO_(3)perovskite successfully.Here we report our high-pressure in situ electrical resistance measurements up to 4.1 GPa for this perovskite sample.At room temperature,the resistance shows special changes at 1.2 and 2.7 GPa.They may indicate the starting and ending points of this transformation.At 4.1 GPa,the negative temperature resistance coefficient is observed,which means that phase Ⅱ could be considered as a semiconductor according to our present measurement.展开更多
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
The dispersive property of the mode Grüneisen parameter in solids is found theoretically.Such a property should appear in a reciprocal relationship to the mode frequency.This phenomenon is also confirmed experime...The dispersive property of the mode Grüneisen parameter in solids is found theoretically.Such a property should appear in a reciprocal relationship to the mode frequency.This phenomenon is also confirmed experimentally in the cases of corundum andα-quartz.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Supported by the National Natural Science Foundation of China under Grant Nos.10032040 and 49774235Foundation of the Geodynamics Opening Laboratory of High-Pressure and High-Temperature.
文摘A transmission-reflection-combined new method is presented for measuring elastic velocities of rocks and minerals at elevated temperature and pressure,which resolves the problems of gradients of temperature and pressure existing in original sample assembly with a pyrophyllite cube.At room temperature and pressure up to 3 GPa,single-crystal quartz and eclogite were used to provide samples under test,respectively.The results of this work agree with the previous measurements very well within the error range.By the use of this new technique,more precise and reasonable data of elastic properties of rocks and minerals at elevated temperature and pressure can be achieved.
基金Supported by the National Basic Research Program of China under Grant No 2011CB808200the National Natural Science Foundation of China under Grant No 11027405+1 种基金the National Natural Science Foundation of China under Grant Nos 10976018 and 11179030the Foundation of LSD under Grant No 9140C670203110C6705.
文摘By in situ x-ray diffraction,an isostructural phase transition between two kinds of the cubic PbCrO_(3) perovskites at around 1.6 GPa and room temperature with a 9.8%volume change is discovered.Recently,we have synthesized this cubic PbCrO_(3)perovskite successfully.Here we report our high-pressure in situ electrical resistance measurements up to 4.1 GPa for this perovskite sample.At room temperature,the resistance shows special changes at 1.2 and 2.7 GPa.They may indicate the starting and ending points of this transformation.At 4.1 GPa,the negative temperature resistance coefficient is observed,which means that phase Ⅱ could be considered as a semiconductor according to our present measurement.
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.
文摘The dispersive property of the mode Grüneisen parameter in solids is found theoretically.Such a property should appear in a reciprocal relationship to the mode frequency.This phenomenon is also confirmed experimentally in the cases of corundum andα-quartz.
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.
