排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
针对近二十多年的氢氘物态方程理论研究工作进行了综述分析,结合本课题组改进的自由能模型、直接量子蒙特卡洛和量子分子动力学方法的模拟结果,对多个研究小组采用不同方法获得的氢氘宽区物态方程数据进行了定量评估分析。结果表明:在当前理论框架下,仅基于第一原理数值模拟得到的氢氘物态方程能够描述的热力学相空间有限;多模型集成的H-REOS.3数据库在105K以下温度与数值模拟结果的相对差别较大,且数据稀少,二者均不能满足工程应用需求。建议采用基于半经验模型的宽区域物态方程研究方法,即结合高精度的实验研究、数值模拟和解析模型,构建满足工程应用需求的氢氘宽区实用物态方程。 相似文献
2.
对原子氢在Be(1010)薄膜表面的吸附性质做了第一性原理计算研究.根据原子面间距的不同,可把Be(1010)表面分为两种.计算结果表明,原子氢在这两种表面上的吸附性质显著不同.为阐明和分析这些不同,系统计算和分析了Be(1010)薄膜的表面电子结构、电子功函数、平均静电势和局域电荷密度.这些物理量都自洽地表明,吸附过程中原子氢和表面铍原子间的电荷转移过程对于两种表面是完全不同的.对于L型表面来说,电荷由吸附原子氢向表面Be原子层转移,而对于S型表面而言,电荷转移过程恰恰相反.
关键词:
表面能
功函数
量子尺度效应 相似文献
3.
We present a first-principles scheme to investigate the equation of state (EOS) of porous materials, based on our recently developed modified mean-field potential approach. By taking the effect of the structural parameters on the free energy into account, we calculate the total energy of materials with initial different densities and then study the EOS of porous Mo and Sn as a prototype. The calculated results are in good agreement with the experimental data available, which demonstrates that our scheme is suitable for investigating EOS of porous materials over a wide r~nge of porosities and pressures. 相似文献
4.
为适应中子物理基准实验的细致计算分析,研制了中子光子耦合计算用SC32、SC64两套多群核参数,中子能量上限为14.5MeV,低能端延伸到热能区25keV。配套的光子参数采用20群结构。核素种类涉及总体计算程序用到的五六十种,见表l。 相似文献
5.
Intrinsic Hall effect and separation of Rashba and Dresselhaus spin splittings in semiconductor quantum wells
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We have proposed a method to separate Rashba and Dresselhaus spin splittings in
semiconductor quantum wells by using the intrinsic Hall effect. It is shown that the
interference between Rashba and Dresselhaus terms can deflect the electrons in
opposite transverse directions with a change of sign in the macroscopic Hall
current, thus providing an alternative way to determine the different contributions
to the spin--orbit coupling. 相似文献
6.
氢是自然界最丰富的元素,是天体物理和惯性约束聚变(ICF)研究的重要对象。简要综述了国内外氢及氘宽区物态方程研究进展,特别评述了OMEGA激光装置上的最新冲击压缩实验和理论模型的对比分析情况。在以往数据分析评估基础上,利用改进的化学自由能模型、第一原理数值模拟结果及多参数物态方程模型,构建了氢的宽区物态方程,适用温度、密度范围分别为20~108 K,10−7~2000 g/cm3。与已有多类实验如冲击压缩实验、静高压等温线实验、声速等实验结果对比表明,新构建的氢宽区物态方程具有较高的置信度,为天体物理、惯性约束聚变、国际热核实验堆等工程物理设计提供高精度的支撑数据。氢宽区物态方程的构建及验证方法亦可适用于其同位素氘,该方法构建的氘宽区物态方程与2019年最新发表的主雨贡纽、二次冲击雨贡纽数据的吻合程度明显优于当前国外模型。指出了未来研究需要关注的状态区域。 相似文献
7.
对原子氢在Be(1010)薄膜表面的吸附性质做了第一性原理计算研究.根据原子面间距的不同,可把Be(1010)表面分为两种.计算结果表明,原子氢在这两种表面上的吸附性质显著不同.为阐明和分析这些不同,系统计算和分析了Be(1010)薄膜的表面电子结构、电子功函数、平均静电势和局域电荷密度.这些物理量都自洽地表明,吸附过程中原子氢和表面铍原子间的电荷转移过程对于两种表面是完全不同的.对于L型表面来说,电荷由吸附原子氢向表面Be原子层转移,而对于S型表面而言,电荷转移过程恰恰相反. 相似文献
8.
刘海风张弓木张其黎宋红州李琼赵艳红孙博宋海峰 《高压物理学报》2018,(5):1-24
针对近二十多年的氢氘物态方程理论研究工作进行了综述分析,结合本课题组改进的自由能模型、直接量子蒙特卡洛和量子分子动力学方法的模拟结果,对多个研究小组采用不同方法获得的氢氘宽区物态方程数据进行了定量评估分析。结果表明:在当前理论框架下,仅基于第一原理数值模拟得到的氢氘物态方程能够描述的热力学相空间有限;多模型集成的H-REOS.3数据库在105K以下温度与数值模拟结果的相对差别较大,且数据稀少,二者均不能满足工程应用需求。建议采用基于半经验模型的宽区域物态方程研究方法,即结合高精度的实验研究、数值模拟和解析模型,构建满足工程应用需求的氢氘宽区实用物态方程。 相似文献
9.
Quantum-state engineering, i.e. active manipulation over the coherent dynamics of
suitable quantum-mechanical systems, has become a fascinating prospect of modern
physics. Here we discuss the dynamics of two interacting electrons in a coupled
quantum dot driven by an external electric field. The results show that the two
quantum dots can be used to prepare a maximally entangled Bell state by changing
the strength and duration of an oscillatory electric field. Different from the
suggestion made by Loss \textit et al (1998 Phys. Rev. A 57 120, the
present entanglement involves the spatial degree of freedom for the two electrons.
We also find that the coherent tunnelling suppression discussed by Grossmann
\textit et al (1991 Phys. Rev. Lett. 67 516 persists in the
two-particle case: i.e. two electrons initially localized in one dot can remain
dynamically localized, although the strong Coulomb repulsion prevents them from
behaving so. Surprisingly, the interaction enhances the degree of localization to a
large extent compared with that in the non-interacting case. This phenomenon is
referred to as the Coulomb-enhanced dynamical localization. 相似文献
10.
Rotation of hydrogen molecules during the dissociative adsorption on the Mg(0001) surface: a first-principles study
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Using first-principles calculations,we systematically study the potential energy surfaces and dissociation processes of the hydrogen molecule on the Mg(0001) surface.It is found that during the dissociative adsorption process with the minimum energy barrier,the hydrogen molecule first orients perpendicularly,and then rotates tobecome parallel to the surface.It is also found that the orientation of the hydrogen molecule in the transition state is neither perpendicular nor parallel to the surface.Most importantly,we find that the rotation causes a reduction of the calculated dissociation energy barrier for the hydrogen molecule.The underlying electronic mechanism for the rotation of the hydrogen molecule is also discussed in the paper. 相似文献