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基于Gray三相状态方程模型,采用GRIZZLY的Grüneisen系数模型,对铅的冲击雨贡纽线、等温压缩线、等熵压缩线和熔化曲线进行了系统计算,优化参数,获得与实验数据一致的冲击雨贡纽线、等温压缩线与等熵压缩线,计算所得熔化温度线与X射线衍射实验结果吻合得很好。 相似文献
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对不同初始密度样品冲击压缩Hugoniot数据的系统分析显示,对每种固体物质而言存在一个表征材料特性的沿其Hugoniot线不随冲击压力而变的经验常数β。β的数值随材料而异。对金属元素而言,该经验特性常数β与初始密实密度ρ0之间遵循同一个幂指数关系。利用该常数β,可很方便地对不同初始密度的Hugoniot数据进行换算,并可以很方便地获得Grüneisen参数。还对β值为常数的适用范围作了讨论。 相似文献
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利用“脉冲回波重合法”测量了多晶LY12铝在流体静压加载下的纵波与横波声速随压力的变化。并根据较低压力(<0.5 GPa)下的超声测量数据所确定的零压弹性模量及其对压力的偏导数,导出了LY12铝的Murnaghan、Birch-Murnaghan、Vinet三种不同形式的等温状态方程,发现由超声测量数据导出的Vinet 状态方程能很好地描述面心立方(fcc)结构的铝与铝合金在较高压力(约200 GPa)下的压缩特性。此外,由超声数据计算了LY12铝在室温常压条件下的Debye温度为430.97 K、热力学Grüneisen系数为2.025、平均声模Grüneisen系数为2 379。 相似文献
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根据固体材料的三项式物态方程和Grüneisen物态方程,导出了沿等压路径求解疏松材料冲击温度和压缩体积随初始密度变化的微分方程组。从体积的微分方程出发,在假定Wu-Jing参量为常数的前提下,导出了冲击压缩体积和体积-焓物态方程的Wu-Jing表达式。采用数值差分方法求解微分方程组,计算了疏松铜的冲击压缩特性,并与文献中部分实验数据进行了比较,特别强调了热电子对冲击压缩体积、冲击温度和Wu-Jing参数的贡献。还讨论了Grüneisen物态方程与Wu-Jing物态方程的内在联系及后者的适用范围。 相似文献
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将冲击Hugoniot线作为Grüneisen物态方程的参考线,以冲击的初始状态为参考状态,推导得到线性和二次曲线表示的冲击绝热线所对应的等熵压缩线方程,计算了200 GPa压力范围内铝和铜两种材料的等熵压缩线,并且计算了以Hugoniot关系为基础的Appy经验物态方程导出的等熵压缩线。计算结果表明,以Appy经验物态方程导出的等熵压缩线与以线性冲击绝热线导出的等熵压缩线接近,在200 GPa压力范围内两者相差不到1.5%。将计算得到的铝的等熵压缩线与美国Sandia实验室ICE实验Z864数据进行了比较,由线性Hugoniot得到的等熵压缩线与实验数据相差不到1%,由Appy经验物态方程得到的等熵线与实验数据几乎重合,说明在200 GPa压力范围内,以Appy物态方程和以线性Hugoniot为参考来计算的等熵压缩线有较高的精度。 相似文献
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利用Birch-Murnaghan有限应变状态方程和Grüneisen状态方程,计算了钙钛矿型(Mg0.86Fe0.14SiO3)和方镁石(Mg0.86Fe0.14O)与斯石英(SiO2)混合物(摩尔比为1∶1)的Hugoniot压力-密度关系。将计算结果与实验数据比较后表明,在相同压力但不同温度的区域,上述两组相态都可能是顽火辉石的高温高压相态。但进一步通过与PREM的比较和分析后表明,在下地幔压力和温度条件下顽火辉石的相态应该是稳定的钙钛矿型,从而支持了Knittle等人的看法。 相似文献
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The present work proposes a theoretical method called ionization dynamics to derive the ionic charge state distribution. Using relativistic quantum mechanics to calculate the energy level lifetime and average ionic lifetime of each ion, the first-order ionization rate constant can be obtained. Based on these data, from the solution of differential equations for consecutive-irreversible ionization reactions, one will be able to derive the ionic charge state distribution.The calculated average positive charge 49.24 of Au48 ~ Au52 and their relative distribution are in good agreement with the results of Lawrence Livermore National Laboratory. 相似文献
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W.J. Nellis 《高压研究》2013,33(4):393-407
The method of deriving shock wave reduced isotherms (SWRIs) as pressure standards up to 150 GPa in a diamond anvil cell (DAC) is discussed. This method is applicable to any adiabatic compression. Hugoniots and isentropes can both be used as reference curves in this analysis. While only Hugoniots have been used to date, isentropes will probably be used in future to develop standards above ~ 200 GPa. Accuracies of SWRIs of Al, Cu, Ta, W, Au, Mo, and Pt are discussed. Hugoniots of diamond and MgO are in excellent agreement with their respective isotherms measured in DAC up to 140 and 55 GPa, respectively. The equation of state of a weakly compressible material is sensitive to pressure and weakly sensitive to temperature. Thus, strong crystals, such as diamond, MgO, and BN, can be used as pressure standards and temperature can be measured independently. Future experiments to improve accuracies of static-pressure standards are suggested. 相似文献
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电子离子碰撞电离过程在超组态碰撞辐射(SCROLL)模型中真实模拟非局域热动力学平衡(non-LTE)高Z材料Au激光等离子体M带谱5f-3d跃迁中各种复杂离子的电离态特性,诸如离子的平均电离度和电荷态分布是一个主要过程.基于准相对论扭曲波玻恩交换近似,采用组态平均的方法,从头计算了金M带类铁金离子-类锗金离子的电子离子碰撞电离速率系数,其中电离截面的高能行为由Bethe系数决定.结果表明:在"神光Ⅱ"实验装置诊断的电子温度~2keV,电子密度~6×1021cm-3范围内,这些参数有利于使用超组态碰撞辐射模型拟Au的激光等离子体M带细致谱5f-3d跃迁的平均电离度和电荷态分布. 相似文献
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The dependence of K+ production on the nuclear equation of state is investigated in heavy-ion collisions. An increase of the excitation function of K+ multiplicities obtained in heavy (Au+Au) over light (C+C) systems when going far below threshold which has been observed by the KaoS Collaboration strongly favors a soft equation of state. This observation holds despite the influence of an in-medium kaon potential predicted by effective chiral models which is necessary to reproduce the experimental K+ yields. 相似文献
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针孔辅助点投影诊断方法实验研究 总被引:7,自引:0,他引:7
针孔辅助点投影背光成像是近几年国外新兴的等离子体诊断技术,在惯性约束聚变相关物理实验诊断中具有重要的应用前景.为验证这一诊断方法的实用性,在神光Ⅱ第九路平台上开展了演示实验.利用激光驱动平面Ti靶获得约4.7 keV的Ti K壳层X射线,在十几微米的针孔约束下作为次级点源并对Au栅格样品投影成像,并用CCD记录.实验成功获得了清晰的样品二维空间分辨的时间积分图像,空间分辨力优于16.1 μm.实验结果表明针孔辅助点投影具有较高的空间分辨力、较大的视场、较高的图像对比度,将成为瑞利泰勒不稳定性研究、激光状态方程研究等物理实验的重要诊断方法之一. 相似文献
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用RKR(Rydberg-Kleinn-Rees)方法计算了Cs2分子的X^1∑g和A^1∑u的势能曲线,求解了Cs2分子核运动的径向薛定谔方程,获得X态与A态间跃迁的Franck-Condon因子和1.06μm附近区域的吸收光谱,并与实验测得的吸收光谱作了比较,两者相当符合。 相似文献
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W. Akutagawa D. Turnbull W.K. Chu J.W. Mayer 《Journal of Physics and Chemistry of Solids》1975,36(6):521-528
The solubility of Au in CdTe, at 800°C and 900°C, has been determined as a function of Pcd (stoichiometry), and the lattice location of the Au has been investigated by ion channeling (2 MeV, 4He+) techniques. The measured Au solubilities varied from ~1018cm?3 to ~1020cm?3 and were found to increase with increasing temperature and with decreasing cadmium partial pressure roughly as . Lattice location studies showed that from ~50% to ~80% of the Au remained in a substitutional, dissolved state after quenching to room temperature. In addition, angular yield scans indicate that the substitutional fraction of the incorporated Au is displaced off lattice sites by ~0·2 Å. No flux peaking was seen in the angular yield scans and the non-substitutiolial fraction of the incorporated Au, manifested at room temperature, may consist either of precipitated or (displaced) interstitial Au. Diffusion coefficients of Au in CdTe have been estimated at 900°C, at the extreme boundaries of the phase field, using the ion channeling technique. The results indicate that the Au diffusivity decreases markedly with increasing Pcd.These observations are found to be consistent with a dissociative model for Au in CdTe in which the major native defects are doubly ionized cadmium Frenkel defects and approximately singly ionized substitutional Au. 相似文献
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任意反射面速度干涉仪(VISAR)具有很高的测试精度, 能实现冲击波速度、粒子速度的连续测量, 是目前冲击波传播相关物理实验的主要诊断设备. 神光II高功率激光装置上的速度干涉仪其空间分辨率优于7 μm, 靶面视场约为1 mm, 探针光脉冲宽度约为 60 ns, 能满足各类冲击波相关实验的诊断. 该VISAR系统用偏振分光镜和波片系统组成了能量调节系统, 极大地方便了探针光能量和条纹相机匹配的调节; 利用新颖的探针光引入系统, 极大地提高了探针激光的能量利用率 (相对其他方法, 能量利用率提高了3倍). 该速度干涉仪已成功应用于状态方程实验、等熵压缩实验和冲击波追赶实验. 本文利用激光脉冲整形技术获得了无冲击压缩实验图像, 利用石英作为标准材料获得了聚苯乙烯 (CH)的Hugoniot数据, 利用双脉冲激光获得了石英材料中冲击波追赶 的实验图像并与理论模拟进行了对比, 实验和模拟符合得比较好. 实验结果表明, 神光II装置上的速度干涉仪能满足不同时间尺度(亚ns---几十ns) 冲击波传播相关物理实验的诊断, 为进一步开展CH的高精度Hugoniot参数测量、 高压无冲击压缩实验和冲击波时空整形实验奠定了基础. 相似文献
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A. Andronic J. Łukasik W. Reisdorf W. Trautmann 《The European Physical Journal A - Hadrons and Nuclei》2006,30(1):31-46
Excitation functions of flow and stopping observables for the Au+ Au system at energies from 40 to 1500MeV per nucleon are
presented. The systematics were obtained by merging the results of the INDRA and FOPI experiments, both performed at the GSI
facility. The connection to the nuclear equation of state is discussed. 相似文献