热力学平衡中的假想态浅议

在热力学平衡中,假想态概念可拓展应用于稀溶液中溶质化学势等温式的推导、非均相体系中平衡常数的计算及电化学体系中电极电势的求算等。     

A Model Study of Equation of State of QCD at Finite Chemical Potential and Zero Temperature

In this paper, we give a direct method for calculating the partition function, and hence the equation of state （EOS） of QCD at finite chemical potential and zero temperature. In the EOS derived in this paper the pressure density is the sum of two terms： the first term P（μ）｜μ=0 （the pressure density at μ = 0） is a μ-independent constant; the second term, which is totally determined by G[μ] （p） （the dressed quark propagator at finite μ）, contains all the nontrivial μ-dependence. By applying a general result in the rainbow-ladder approximation of the Dyson-Schwinger approach obtained in our previous study [Phys. Rev. C 71 （2005） 015205], G[μ]（p） is calculated from the meromorphic quark propagator proposed in [Phys. Rev. D 67 （2003） 054019]. From this the full analytic expression of the EOS of QCD at finite μ and zero T is obtained （apart from the constant term P（μ）｜μ=0, which can in principle be caJculated from the CJT effective action）. A comparison between our EOS and the cold, perturbative EOS of QCD of Fraga, Pisarski and Schaffner-Bielich is made. It is expected that our EOS can provide a possible new approach for the study of neutron stars.     

Realization of Spin Switch in a Triple-Terminal Double-Quantum-Dot Structure

Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magnetic flux the conductances for the two channels present remarkable difference from each other. When the quantum dots are made of ferromagnetic materials, the levels of quantum dots are spin dependent, then spin polarization comes about in the two channels. Furthermore, in some regions spin polarization in the different channels are opposite. We consider that this model can be a device prototype for spin filtering and spin separation.     

气体混合物各组分化学势的Monte Carlo模拟

在则系综测试粒子Ｍｏｎｔｅ Ｃａｒｌｏ （ＧＣＭＣ）方法模拟常温下空气（以氮气为代表）及其污染物微量有机物（以苯为例）的混合物中各组分的化学势。模拟中,氮气和苯分子采用ＬＪ球型分子势能模型,采用Ｍｅｔｒｏｐｏｌｉｓ抽样及周期边界条件。通过模拟并拟合得到了３００．２Ｋ、苯的摩尔分数为０．０６２５,氮气及苯化学势与压力的关联式,以用于狭缝碳孔中该混合物体系的选择性吸附。     

Linear Chemical Potential Dependence of Two-Quark Condensate

By differentiating the inverse dressed quark propagator at finite chemical potential μ with respect to μ, the linear response of the dressed quark propagato r to the chemical potential can be obtained, From this we extract a modelindependent formula for the linear chemical potential dependence of the in-medium two-quark condensate and show by two independent methods （explicit calculation and Lorentz covariance arguments） that the first-order contribution in μ to the in-medium two-quark condensate vanishes identically. Therefore if one wants to study the in-medium two-quark condensate one should expand to at/east the second order in the chemical potential μ.     

应用化学势曲线对气液相平衡和质量转移问题的分析

提出应用化学势与压强的关系曲线分析曲面气液两相的相平衡及物质质量转移问题的方法.通过曲线描述,提供了关于相平衡、弯曲液面饱和蒸气压以及蒸发、凝结等规律比较直观的物理图像.     

固—气相平衡时的蒸气压方程

本文以固气平衡为例，当考虑到潜热与温度的关系时，深入地讨论了克劳修斯－克拉珀龙方程或称蒸气压方程的形式。     

三维纳米液膜沉积结构的模拟研究

基于三维动力学蒙特卡罗模型,再现了纳米液膜干燥后形成的双尺度沉积结构,探究了液体化学势、纳米粒子移动速率、液体临界蒸发率以及化学势锐度等参数对纳米液膜沉积结构的影响。结果表明,纳米液膜干燥时,液膜中的纳米粒子随着三相线移动自组装形成各种各样的沉积结构沉积在基板上。纳米液膜蒸发过程中,当液体蒸发达到临界蒸发率时液体化学势将发生突变,使其形成两种沉积结构。随液体初始化学势的增大,沉积结构逐渐变为均匀分布的密集网状结构。液体临界蒸发率越小,液体化学势突变后形成的沉积结构越明显。纳米粒子的移动速率越快,沉积结构中的枝状结构越少。化学势锐度对双尺度沉积结构的差异有很大的影响,锐度越大,两种沉积结构的差异越大。     

簇合物(p-H2)N-HCCCN的结构和能量

采用两体作用势模型和遗传算法对簇合物(p-H2)NHCCCN的极小能量结构和能量进行了理论研究.结果表明,20个para-H2分子形成HCCCN周围的第一个溶剂层,第一个溶剂层包含三个溶剂环,每个溶剂环都有6个para-H2分子,第19和20个para-H2分子分别聚集在HCCCN分子的N、H原子末端.进一步计算了(p-H2)N-HCCCN的化学势,发现化学势随para-H2分子个数的增加呈震荡变化.     

关于化学势是否等于零的问题

当系统中的粒子在变化时不受任何约束，其化学势就等于零；若粒子数保持固定不变，或在变化时要受到某种条件的约束，化学势就不等于零。