共查询到19条相似文献,搜索用时 156 毫秒
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用修正的WCA状态方程和Ross变分微扰理论计算了液氩冲击压缩曲线,计算中体系分子间相互作用势选择EXP-6有效两体势模型,计算结果与Nellis等人的实验数据符合较好。 相似文献
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用修正的WCA状态方程和Ross变分微扰理论计算了液氩冲击压缩曲线,计算中体系分子间相互作用势选择EXP-6有效两体势模型,计算结果与Nellis等人的实验数据符合较好. 相似文献
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用MCR液体变分微扰理论计算了苯冲击压缩曲线,计算中苯分子间相互作用势采用EXP-6等效两体势模型,势参数通过对实验数据的拟合优选,计算中采用了Tang修正后的硬球径向分布函数.计算结果在未反应段与Dick等人的实验数据符合较好.计算结果表明苯的振动激发对其冲击物性有着重要影响,选α值为13.4能更准确地反映苯分子间的相互作用.? 相似文献
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用Exp-6有效两体势模型和液体变分微扰理论计算了液Ar冲击压缩曲线,在35 GPa以下的压力范围内计算的冲击压缩曲线与Thiel 及Nellis等人的实验数据进行了比较.液体分子间Exp-6有效两体势参数根据实验数据计算优选出最佳值,计算结果表明得到的优选参数较为准确地描述了液Ar分子间相互作用.由理论结合实验数据可以认为液氩体系在冲击压力36 GPa以下无相变现象.对较高冲击压力下理论计算的冲击曲线和实验结果之间的偏差作了分析,结合不透明度实验的结果,得到当压力超过35 GPa,温度在12 000 K 相似文献
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基于量子化学从头计算方法,计算了处于高密度条件下氮分子之间的两体排斥势和三体关联势,并采用球面平均近似求得了它们各自的高温平均势能值,得到了包括三体关联效应的等效两体势函数与分子间距的解析关系。借助分子流体微扰变分理论,并考虑van der Waals长程作用,分别采用总平均两体势和总等效两体势,计算了液氮的冲击压缩曲线。计算结果表明,在不需要考虑分子离解的压缩范围内(1~35 GPa),三体关联效应的贡献使分子间总等效两体势函数比单独两个分子间总平均作用势函数明显软化,与实验Hugoniot数据结果一致。 相似文献
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Based on the thermodynamics statistic method, the improved variational perturbation theory and the modified quantum mechanics
correction model have been used to calculate the equation of state of liquid helium at pressure from 0.7 to 108 GPa. The calculation
results are in good agreement with the experimental data. The EXP-6 potential (α = 13.1) can more accurately describe the interaction of helium atoms than other potentials in the scheme. Finally, a comparison
is shown between our interatomic potentials and other potentials. 相似文献
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Abstract Thermodynamic properties of fluid neon were calculated between 73 and 348 K and up to the melting line, using Ross’ variational perturbation theory. Parameter values for the EXP-6 potential were determined from experimental sound velocity data in the range 100–300 K, 0.1–1 GPa. Calculations with this and several pure pair potentials (XC, HFD), with and without more body interactions, were compared with experimental pVT and sound velocity data. The EXP-6 potential describes the experimental data up to 1 GPa with an accuracy of almost the experimental error. An equation of state is presented in the range from 98 to 348 K and from 0.6 to 6 GPa. 相似文献
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利用二级轻气炮在3.75~57.87 GPa 压力范围内,对体积比为10∶10∶1的液态水-苯-壬基酚聚氧乙烯醚混合体系进行了动高压加载实验,获得了10个Hugoniot数据。拟合结果表明,该混合体系的D-u关系可近似用直线方程D=1.407+1.503up描述,拟合精度约为0.102。混合体系H2O-C6H6-C35H64O11的冲击压缩实验结果基本符合体积相加原理,而在给定的实验压力区间内,冲击绝热曲线发生多次拐折的事实意味着该系统可能在6 GPa、10 GPa和30 GPa压力点附近发生了多次结构性相变。另外,还讨论了Lawrence-Berthlot混合规则中修正因子对高密度条件下指数-6型相互作用势排斥部分的影响。 相似文献
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The theory and potentials described in the preceding paper are used for the calculation of thermodynamic properties of fluid neon between 73 and 348 K and up to the melting line. A polynomial equation of state for correlating the densities between 73 and 323 K and between 30 MPa and 1 GPa is presented. The calculations have been extended up to 6 GPa and the performance of the EXP-6 effective pair potential and the HFD-C2, HFD-B and XC3 pure pair potentials is compared. The effect of the Axilrod-Teller many-body correction term on the pure pair potentials is studied. In the ranges 98-348 K and 0·6-6 GPa the density data are correlated by a MBWR equation of state, and a polynomial expression is given for the sound velocity in these ranges. The pressure and temperature dependences of the specific heat at constant volume are shown. A comparison is made between the experimental pVT and soundvelocity data of Kimura et al. at 295 K and up to 3·5 GPa and our calculations. 相似文献
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采用热力学统计理论研究了液态甲烷在高温高压下分子分解反应特点及该体系的物态方程。着重讨论了体系中CH4-H2分子间有效势对体系化学反应平衡及物态方程的影响,并根据实验Hugoniot点(pH, V)优化确定出其exp-6势函数中的参数值。该势函数的排斥部分值比理想混合条件下Lorentz-Berthelot规则给出的势函数值低约50%,预示着高压下CH4和H2之间存在着某种亲合性。用该势函数计算得到的p-T线与现有的两个实验点符合很好。还讨论了CH4-H2之间的有效作用势参数对CH4分子冲击离解度(x)的影响。 相似文献
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The anisotropy of two successive transitions of the spin-ladder compound LiCu2O2 is studied by the specific heat ( C) under magnetic fields with H / / c and H / / ab (written as H^c and H^ab in the following) up to 14 T. The peak of specific heat at 24.5 K in zero field shifts to lower temperature when the field is increased and the magnitude of the peak is suppressed by the field. On the contrary, the peak of 22.5 K shifts to higher temperature, especially at 14 T. Its magnitude increases in the field of H^c, whereas it decreases in the field of H^ab. We calculate the entropy change between 21 K and 63 K. The different influence of the spin ordering by fields of different direction is obtained. Our experimental results suggest a mixed state between the long range incommensurate helimagnetic ground state and the higher-T short-range dimer liquid state. The temperature range of mixed state is shrunk with the increasing field. Possible mechanism is discussed. 相似文献
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用阻抗匹配法和压电探针技术测量了初始密度为1.714 g/cm3(孔隙率α=ρ0/ρ00=1.898/1.714=1.107)的水绿矾(FeSO4·7H2O)的冲击压缩线,发现其在0~100 GPa范围内存在两个明显相区:含有部分熔融的低压相和完全熔化的高压相。在两个相区内,冲击波速度D和波后粒子速度u可分别描述为:D=0.59+2.06u(u<3.12 km/s)和D=3.18+1.223u(u≥3.12 km/s)。从冲击压缩数据出发,用欧拉有限应变理论得到了其等熵状态方程。其熔化方程可用pm(GPa) =0.159(Tm(K)/1000)6.3371+0.69来近似描述。 相似文献
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This paper reports on a study of the luminescence of single crystals of silver thiogallate (AgGaS2). Cathodoluminescence measurements were made between liquid helium temperature and 250°K at two voltages, 25 kV and 10 kV and for 6 and ⊥ polarizations at the c axis. The cathodo-excitation technique used revealed the self-absorption phenomena, which are considerable near the bandgap.It is shown that the excitonic emission observed at liquid helium temperature remains up to 150°K and at higher temperatures there is band to band transition. In addition, a free to bound type of luminescence is indicated. This transition would appear to involve a level at 75 meV of the transport band. 相似文献