共查询到19条相似文献,搜索用时 250 毫秒
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在同一理论框架内,基于冲击Hugoniot和热力学参数计算了Al、Cu、W、 Au、Pt、Ta、Ag、Mo、Ni、Co和Zn的300 K等温压缩线,并结合现有静高压实验数据,在160 GPa压力范围内重新标定了红宝石压标。所采用的两种红宝石压标形式的标定结果分别为A=1 923.4 GPa、B=9.75和m=1 889.0 GPa、n=5.48,两者具有非常好的自洽性,200 GPa压力范围内确定的压力偏差小于2.1 GPa。基于提出的红宝石压标,重新计算了3组Au等温压缩实验的加载压力。固定等温体模量为167 GPa,重算的实验数据拟合至Vinet物态方程所得等温体模量对压力的一阶偏导为5.95,与超声实验数据非常吻合。 相似文献
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在对Grüneisen系数高温高压下演化特性不作任何假设的前提下,建立了一种不依赖于等温物态方程具体形式,通过Hugoniot实验数据直接确定0K零压等温体积模量B0K及其对压力的一阶导数B′0K和初始密度ρ0K等0K物态方程输入参数的方法。通过与实验和理论数据的分析和比较,表明用这一方法确定的B0K和B′0K不仅合理,而且具有很高的精度,特别是B′0K的精度,要优于目前传统超声实验的测量精度。此外,这一方法所确定的ρ0K不仅在Gr櫣neisen物态方程的框架内与相应的室温零压特性参数相适配,而且与低温热膨胀实验数据所确定的近0K初始密度ρ0E非常吻合。 相似文献
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在对Gruneisen系数高温高压下演化特性不作任何假设的前提下,建立了一种不依赖于等温物态方程具体形式,通过Hugoniot实验数据直接确定0 K零压等温体积模量B0K及其对压力的一阶导数B'0K和初始密度ρ0K等0 K物态方程输入参数的方法.通过与实验和理论数据的分析和比较,表明用这一方法确定的B0K和B'0K不仅合理,而且具有很高的精度,特别是B'0K的精度,要优于目前传统超声实验的测量精度.此外,这一方法所确定的ρ0K不仅在Gruneisen物态方程的框架内与相应的室温零压特性参数相适配,而且与低温热膨胀实验数据所确定的近0 K初始密度ρ0E非常吻合. 相似文献
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在对Grtineisen系数高温高压下演化特性不作任何假设的前提下,建立了一种不依赖于等温物态方程具体形式,通过Hugoniot实验数据直接确定0K零压等温体积模量B0K及其对压力的一阶导数B′0k。和初始密度ρ0K等0K物态方程输入参数的方法。通过与实验和理论数据的分析和比较,表明用这一方法确定的.B0K和B′0k不仅合理,而且具有很高的精度,特别是B′0k的精度,要优于目前传统超声实验的测量精度。此外,这一方法所确定的ρ0K不仅在Grtineisen物态方程的框架内与相应的室温零压特性参数相适配,而且与低温热膨胀实验数据所确定的近0K初始密度ρ0E非常吻合。 相似文献
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本文针对丝阵Z箍缩等高能量密度物理实验的数值模拟研究, 建立了一种适用温度、密度范围宽的三项式半经验物态方程. 三项式半经验物态方程包括零温自由能项, 电子热贡献项和离子热贡献项. 零温自由能项采用多项式拟合的方法确定. 多项式系数通过多项式计算的结果与高压缩比区域和压缩比为1时零温Thomas-Fermi-Kirzhnits模型计算的结果对应相等得到. 离子对物态方程的热贡献采用一种准谐振模型, 此谐振模型可以描述离子在固态相中的行为, 并且在高温度、低密度区域趋近于理想气体物态方程. 电子对物态方程的热贡献采用含温Thomas-Fermi-Kirzhnits模型计算. 利用所建立的三项式半经验物态方程计算了铝的等温压缩曲线, 并与实验数据做了对比. 给出了很宽温度、密度范围内铝的压强, 其数据与相应的SESAME数据库数据做了对比. 相似文献
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采用原位高压同步辐射X射线衍射技术,利用金刚石对顶砧(DAC)装置产生高压,选用高纯NaCl粉末作为传压介质与标压物质,在室温下、21.5 GPa的压力范围内,测定了铝的等温状态方程。利用Murnaghan方程对实验结果进行了数值拟合,得到铝的零压体弹模量及其一级压力导数分别为B0=(77±2) GPa,B0′=4.8±0.3。该结果同相关文献资料报导的值在误差范围内符合得很好,略显得较大,这是由于传压介质NaCl的非静水压效应所致。在实验所达到的压力范围内,未发现明显的相变迹象。 相似文献
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By using a Mie–Grüneisen-type analysis method, the pressure–volume–temperature equations of state (P–V–T EOSs) of Au and Pt have been determined up to 300?GPa and 3000?K based on the experimental shock Hugoniot and thermodynamic data. The calculated results of Au and Pt show an excellent agreement with available experimental volume compression data over a wide range of pressures and temperatures. A comparison of our results with previous theoretical investigations has also been done. In addition, we have further examined the consistency of our results and the P–V–T EOS of MgO [K. Jin, X.Z. Li, Q. Wu, H.Y. Geng, L.C. Cai, X.M. Zhou, and F.Q. Jing, The pressure–volume–temperature equation of state of MgO derived from shock Hugoniot data and its application as a pressure scale, J. Appl. Phys. 107 (2010), pp. 113518] using simultaneous volume measurements of Au, Pt, and MgO at various temperatures. The good agreement among the P–V–T EOSs of Au, Pt, and MgO implies that these EOSs can be used as the reliable pressure scales in high pressure–temperature diamond anvil cell experiments. 相似文献
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This work provides the first systematic test of validity of the embedded-atom potentials of Mei et al. [Phys. Rev. B 43 (1991) 4653], via a complete study of the vibrational and thermodynamic properties of isoelectronic transition (Ni, Pd, Pt) and noble (Cu, Ag, Au) metals. Phonon dispersion curves and thermal properties are studied within the quasiharmonic approximation. Results for the temperature-dependence of the lattice constants, coefficients of linear thermal expansion, isothermal and adiabatic bulk moduli, heat capacities at constant volume and constant pressure, Debye temperatures and Grüneisen parameters are presented. Electronic contribution to the specific heat is included explicitly via density-functional calculation. The calculated phonon frequencies for Ag and Cu agree well with the results from inelastic neutron scattering experiments. Despite less satisfactory agreement between calculated and measured phonon frequencies for the other four metals, isothermal and adiabatic bulk moduli and the specific heats of all metals are reproduced reasonably well by the model, while the Grüneisen parameter and Debye temperature are underestimated by about 10%. The coefficient of linear thermal expansion is underestimated with respect to measured values in most cases except for Pt and Au. The results are good for Pt up to 1000 K and for Au up to 500 K. 相似文献
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Xiao-qing DengZu-tong Yan 《Journal of Physics and Chemistry of Solids》2002,63(9):1737-1744
In this paper, Pandey approximation for the volume dependence of Anderson-Grüneisen parameter at fixed pressure, Anderson approximation for the temperature dependence of thermal expansivity, the equations of thermal expansivity along isobars derived by Shanker et al., and the presented approximation for the volume dependence of Anderson-Grüneisen parameter along isobars, have been used to study and predict the pressure-volume-temperature (P-V-T) data and the variations of the volume expansion coefficient and isothermal bulk modulus with temperature and pressure for NaCl, CsCl, LiF, NaF crystals, up to 30 GPa and in the temperature range 298-1073 K. The calculated values are compared with each other. It is found that these equations-of-state are valid and present good agreement with the available experimental data. 相似文献
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Semiempirical equations of state (EoS) of Au, Pt, MgO, NaCl-B1, and NaCl-B2 based on expanded Mie–Grüneisen–Debye approach, which are consistent both with the Mie–Grüneisen–Bose–Einstein approach and the thermochemical, X-ray, ultrasonic and shock-wave data in a wide pressure-temperature range, have been constructed. It is shown that to determine the volume dependence of the Grüneisen parameter, not only shock-wave and static compression data, but also experimental information on heat capacity, bulk moduli, volume, and thermal expansion coefficient at zero pressure need to be taken into account. Intrinsic anharmonicity is of great importance at construction of EoS at high temperatures and x=V/V 0>1. Cross-comparison of the current equations of state with independent measurements shows that these EoS may be used as the internally consistent and independent pressure scales in a wide range of temperatures and pressures. 相似文献
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高压下钙钛矿结构MgSiO3的分子动力学研究 总被引:1,自引:0,他引:1
利用分子动力学方法,研究了高温高压下钙钛矿结构MgSiO3的状态方程.研究表明,分子动力学模拟结果很好地再现了广泛温度和压强范围内钙钛矿结构MgSiO3的摩尔体积.温度300 K压强上升到120 GPa模拟的钙钛矿结构MgSiO3状态方程和有效的实验结果基本一致.在更高温度和更高压强下模拟的钙钛矿结构MgSiO3状态方程和他人的计算值吻合的很好.另外,还分别计算了温度300 K,900 K,1500 K和2500 K压强上升到120 GPa时MgSiO3的体积压缩率. 相似文献
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The temperature dependence of the bulk modulus of ZrB2 above room temperature was calculated by using the equations by Garai and Laugier (J. Appl. Phys. 101 (2007) p.023514) and Lawson and Ledbetter (Philos Mag. 91 (2011) p.1425). The present calculations involve the accurate data for pressure derivative of the bulk modulus for the Anderson–Grüneisen parameter in addition to the other experimental parameters involved. It is interesting to note that the cited equations derived by different thermodynamic approaches give almost equivalent values for the temperature dependencies of the bulk modulus of ZrB2. The present results for the temperature derivatives of the bulk modulus of ZrB2 vary from ?0.016?GPa/K at 300–400?K to ?0.022?GPa/K at 1500–1600?K, being in good agreements with the corresponding experimental values. 相似文献
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The pressure-volume-temperature (P-V-T) equation of state (EOS), isothermal bulk modulus, and thermal expansivity of CaF2 with cubic fluorite-type structure are investigated using the constant temperature and pressure shell model molecular dynamics (MD) method with effective pair potentials which consist of the Coulomb, dispersion, and repulsion interaction. It was shown that MD simulation is very successful in accurately reproducing the measured volumes of the CaF2 over a wide range of pressures. The simulated P-V data matched X-ray diffraction experimental results up to 9.5 GPa at 300 K. In addition, volume thermal-expansion coefficient and isothermal bulk modulus were also calculated and compared with available experimental data and the latest theoretical results at ambient condition. At extended temperature and pressure ranges, The P-V EOS under different isotherms at selected temperatures, T-V EOS under different isobars at selected pressures, thermal expansivity, and isothermal bulk modulus were predicted up to 1500 K and 10 GPa. The detailed knowledge of thermodynamic behavior and EOS at extreme conditions are of fundamental importance to the understanding of the physical properties of CaF2. 相似文献
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It has been demonstrated that the spinodal model produces very well the isothermal compressibility of liquid methanol for a wide range of pressures and temperatures. We have used the pseudospinodal model further to determine pressure derivatives, first-order as well as second-order of isothermal compressibility and bulk modulus for liquid methanol in the range of pressures (0–100 MPa) and temperatures (208.17 K–298.16 K). The results have been found to present close agreement with the available experimental data. We have also calculated the values of densities as a function of pressure and temperature for methanol using the Stacey equation of state. 相似文献