反常磁矩对弱磁场弱相互作用费米气体热力学性质的影响

考虑费米子的反常磁矩, 运用赝势法和热力学理论, 导出弱磁场中弱相互作用费米气体自由能的解析式, 以此为基础给出高温和低温情况下系统热力学性质, 分析反常磁矩对热力学性质的影响机理. 研究表明: 反常磁矩对热力学性质的影响与温度相关, 而且这种影响随温度的上升在低温区是增大的, 在高温区是减小的; 对于系统的化学势、内能, 反常磁矩加强了磁场的影响, 弱化了相互作用的影响; 对于系统的热容量, 反常磁矩在低温区使其减小, 在高温区使其增加.     

Quantum thermodynamic processes: a control theory for machine cycles

The minimal set of thermodynamic control parameters consists of a statistical (thermal) and a mechanical one. These suffice to introduce all the pertinent thermodynamic variables; thermodynamic processes can then be defined as paths on this 2-dimensional control plane. Putting aside coherence we show that for a large class of quantum objects with discrete spectra and for the cycles considered the Carnot efficiency applies as a universal upper bound. In the dynamic (finite time) regime renormalized thermodynamic variables allow to include non-equilibrium phenomena in a systematic way. The machine function ceases to exist in the large speed limit; the way, in which this limit is reached, depends on the type of cycle considered.     

Statistic properties of Fermi gas in a strong magnetic field

Based on the thermodynamic potential function of Fermi gas in a strong magnetic field, using the thermodynamics method, the integrated analytical expressions of thermodynamic quantities of the system at low temperatures are derived, and the effects of the magnetic field on the statistic properties of the system are analysed. It is shown that, as long as the temperature is not zero, the effects of the magnetic field on the thermodynamic quantities of the system contain both oscillatory and non-oscillatory parts. For the non-oscillatory part, compared with the situation of Fermi gas in a weak magnetic field, the influence of the magnetic field on the thermodynamic quantities is not exactly the same. For the oscillatory part, the period and amplitude of the oscillation are all related to the magnetic field. Due to the oscillation, the chemical potential may be greater than Ferim energy of the system, but the oscillation does not affect the thermodynamic stability of the system.     

Analytic phase structures and thermodynamic curvature for the charged AdS black hole in alternative phase space

In this paper, we visit the thermodynamic criticality and thermodynamic curvature of the charged AdS black hole in a new phase space. It is shown that when the square of the total charge of the charged black hole is considered as a thermodynamic quantity, the charged AdS black hole also admits a van der Waals-type critical behavior without the help of thermodynamic pressure and thermodynamic volume. Based on this, we study the fine phase structures of the charged AdS black hole with fixed AdS background in the new framework. On the one hand, we give the phase diagram structures of the charged AdS black hole accurately and analytically, which fills up the gap in dealing with the phase transition of the charged AdS black holes by taking the square of the charge as a thermodynamic quantity. On the other hand, we analyse the thermodynamic curvature of the black hole in two coordinate spaces. The thermodynamic curvatures obtained in two different coordinate spaces are equivalent to each other and are also positive. Based on an empirical conclusion under the framework of thermodynamic geometry, we speculate that when the square of charge is treated as an independent thermodynamic quantity, the charged AdS black hole is likely to present a repulsive between its molecules. More importantly, based on the thermodynamic curvature, we obtain a universal exponent at the critical point of phase transition.     

Size-dependent thermodynamic criterion for the thermal stability of binary immiscible metallic multilayers

With the aim of understanding the thermal stability of binary immiscible metallic multilayers, we propose a generally size-dependent thermodynamic criterion for determining the interface alloying in multilayers, with respect to the size-dependent interface energy of binary metal systems. Taking the copper/tungsten bilayer as an example, we obtain the interfacial alloying phase diagram based on the proposed thermodynamic model. Our theoretical predictions are consistent with experiments, implying that the size-dependent thermodynamic criterion of the thermal stability could be expected to be applicable to many multilayers.     

Possible canonical distributions for finite systems with nonadditive energy

It is shown that a small system in thermodynamic equilibrium with a finite thermostat can have a q-exponential probability distribution which closely depends on the energy nonextensivity and the particle number of the thermostat. The distribution function will reduce to the exponential one at the thermodynamic limit. However, the nonextensivity of the system should not be neglected.     

Finite-size effects in a D-dimensional ideal Fermi gas

By using the Euler-MacLaurin formula,this paper studies the thermodynamic properties of an ideal Fermi gas confined in a D-dimensional rectangular container.The general expressions of the thermodynamic quantities with the finite-size corrections are given explicitly and the effects of the size and shape of the container on the properties of the system are discussed.It is shown that the corrections of the thermodynamic quantities due to the finite-size effects are significant to be considered for the case of strong degeneracy but negligible for the case of weak degeneracy or non-degeneracy.It is important to find that some familiar conclusions under the thermodynamic limit are no longer valid for the finite-size systems and there are some novel characteristics resulting from the finite-size effects,such as the nonextensivity of the system,the anisotropy of the pressure,and so on.     

NO分子宏观气体热力学性质的理论研究

采用量子统计系综理论,研究了基态NO分子宏观气体摩尔熵、摩尔内能、摩尔热容等热力学性质.首先应用课题组前期建立的变分代数法(variational algebraic method, VAM)计算获得了基态NO分子的完全振动能级,得到的VAM振动能级作为振动部分,结合欧拉-麦克劳林渐进展开公式的转动贡献,应用于经典的热力学与统计物理公式中,从而计算得到了1000-5000 K温度范围内NO宏观气体的摩尔内能、摩尔熵和摩尔热容.将不同方法计算得到的摩尔热容结果分别与实验值进行比较,结果表明基于VAM完全振动能级获得的结果优于其他方法获得的理论结果.振动部分采用谐振子模型对无限能级求和计算热力学性质的方法有一定的局限性,应当使用有限的完全振动能级进行统计求和.     

The evaluation of the thermodynamic factor for the diffusion of cations in pure oxides and in solid solutions of the (A,B)O type

An analysis of the expression of the thermodynamic factor for the metal diffusion in a pure oxide is presented, showing that this is in general very different from one and is a function of the oxygen activity. The same analysis is then extended to the case of solid solutions formed between oxides having the same type of defect structure. It is found that in this case the thermodynamic factor becomes a function of both the oxygen activity and the oxide composition and that in addition it depends also strongly on the ratio between the gradients of these two variables. The expressions developed allow a calculation of the thermodynamic factor to be performed for oxides with a known defect structure: this is carried out for solid solutions between NiO and CoO at 10002C.     

吸附碳泵循环构建与能耗分析:从热力学角度

从热力学角度审视制约吸附法碳捕集技术推广和工业化应用的能耗问题,其实质是对捕集过程中能量在不同形式之间转换机制的深入认识问题.应用热力学中的"循环"这一成熟概念和衍生工具,对能量转换问题展开专题分析应是恰当的。本文基于热力学碳泵概念,从热力学角度进行吸附碳泵循环的构建与能耗分析,将碳捕集能耗分析模型具化至循环层面。从热力学第一定律角度,基于无限碳源、汇假设,定义工作于碳源、汇之间的吸附碳泵循环,形成抽象模型求解理想功耗及循环COPCO2,与混合气体分离模型(MGS)分析结果进行对比,并分析关键循环参数的影响;从热力学第二定律角度,基于状态点过程解耦方法"白箱化"吸附碳泵循环中具体过程,形成具体模型分析循环中熵增、熵产机制,证实优化传热过程、提升吸附剂性能作为有效降低能耗策略在热力学层面的恰当性。     

Thermodynamics and effective temperatures in sheared granular matter and emulsions

Recent theories postulate that the non-equilibrium behavior of systems experiencing jamming or structural arrest could be described by equilibrium thermodynamic concepts. If a thermodynamic framework can describe the behavior of systems far from equilibrium, then an effective temperature with a true thermodynamic meaning exists as a key parameter in characterizing the material's properties. In order to examine the validity of the thermodynamics for jammed systems, we perform a numerical experiment with a realistic granular matter model specially conceived to be reproducible in the laboratory. The results strongly support the thermodynamic picture.     

The reciprocal relations between cross phenomena in boundless gaseous systems

The Onsager-Casimir reciprocal relations obtained for gaseous systems on the basis of the linearized Boltzmann equation in a general form [F. Sharipov, Onsager-Casimir reciprocal relations based on the Boltzmann equation and gas-surface interaction law. Single gas., Phys. Rev. E 73 (2006) 026110] are applied to boundless domains. Under additional assumptions, expressions of the kinetic coefficients obtained previously are significantly simplified and can be easily applied in practice. In contrast to all previous works on this topic, it is shown that for a given set of thermodynamic forces there are several sets of thermodynamic fluxes providing the same entropy production. As a consequence, several forms of the kinetic coefficients satisfying the reciprocal relations do exist for a given set of thermodynamic forces. An illustrative example confirms that in many situations the kinetic coefficients are neither odd nor even with respect to the time-reversal and hence the reciprocal relations between them should be written in more general form than that obtained by Casimir.     

Thermodynamics and phase transition of topological dS black holes with a nonlinear source

We discuss black hole solutions of Einstein-Λ gravity in the presence of nonlinear electrodynamics in d S spacetime. Considering the correlation of the thermodynamic quantities respectively corresponding to the black hole horizon and cosmological horizon of dS spacetime and taking the region between the two horizons as a thermodynamic system, we derive effective thermodynamic quantities of the system according to the first law of thermodynamics, and investigate the thermodynamic properties of the system under the influence of nonlinearity parameter α. It is shown that nonlinearity parameter α influences the position of the black hole horizon and the critical state of the system, and along with electric charge has an effect on the phase structure of the system,which is obvious, especially as the effective temperature is below the critical temperature. The critical phase transition is proved to be second-order equilibrium phase transition by using the Gibbs free energy criterion and Ehrenfest equations.