论范氏气体方程和理想气体状态方程的关系

一般认为范氏气体方程在大体积极限下和理想气体状态方程一样.不过理想气体还要求满足焦耳定律等,也就是内能对体积的偏导数为零.由于内能对体积的偏导数可以化为物态方程的一阶导数,是否能在状态方程一阶导数这一层次上也要求范氏方程的大体积极限和理想气体一致就值得探讨.结果表明:如果在一阶导数层次上比较,范氏气体方程在大体积极限下不能再回复到理想气体.推广范氏方程让范氏系数依赖于温度,可以得到实际气体在大体积极限下的一个渐近形式.     

理想气体与范氏气体在任意准静态过程中的摩尔热容

导出了理想气体与范氏气体在任意准静态过程中的摩尔热容公式。     

范氏气体PVT的图形特点

由于许多状态方程都是由范氏气体状态方程演变而来的，研究该方程就具有非常重要的意义，本文给出了绘制范氏气体状态方程三维曲面的方法和程序。     

从理想气体压强到大气压强的教学讨论

从理想气体模型出发,讨论压强产生的物理实质,推广到大气层中的空气,考虑其因重力影响使粒子数密度按势能分布,导致大气压强随高度发生变化.这一分析讨论过程能帮助学生建立清晰的物理认知,有效地培养学生的科学思维、分析解决实际问题的能力.     

范氏方程、玻意耳温度与理想气体状态方程的偏差

1 引言 众所周知,理想气体状态方程只适用于稀薄的气体,从分子动理论看,理想气体的分子间没有相互作用力,理想气体是"永久气体",不可能液化.     

理想气体压强公式的一种推导方法

本文从球形容器中理想气体入手，用一种简单易懂且不失一般性的方法，推导出理想气体压强公式。     

理想气体压强公式两种推导方法及其比较

本文分别从球形容器和长方形容器中理想气体入手，给出平衡态下理想气体的压强公式的两种推导方法，并将两种推导方法加以比较。     

关于理想气体的绝热过程方程

求出经典和量子理想气体的绝热过程方程，并进行了一些必要的讨论．     

范氏气体的准静态绝热方程

应用两种不同方法导出范氏气体的准静态绝热方程，解决了相关文献未能解决的问题．     

麦克斯韦等面积法则在范氏气体中的应用

对与范德瓦耳斯气体状态方程有关的几个问题作了进一步分析,给出了一种证明麦克斯韦等面积法则的方法,并指出了有关文献的不妥之处.     

Roe Linearization for the van der Waals Gas

An extension of the Roe linearization method to nonideal gases is described and applied to the particular case of the van der Waals gas. A supplementary relation connecting the thermodynamic variables is introduced to decouple the evaluation of the intermediate velocity and total specific enthalpy from the determination of the intermediate density, needed in the Jacobian matrix of the linearization due to the general thermodynamic character of the gas. The density value is obtained by solving the supplementary equation, which involves the Roe average of velocity and enthalpy, and that in the case of the polytropic van der Waals gas is a third-order algebraic equation. Numerical results are shown including classical and nonclassical behaviour in one-dimensional shock tube problems.     

On the van der Waals interaction of carbon nanocones

Based on the continuum Lennard-Jones model, the van der Waals interaction of two concentric and eccentric carbon nanocones with different or identical sizes are investigated in this paper. Also, on the basis of classical mathematical modeling techniques, a new semi-analytical solution is given to evaluate the van der Waals potential energy and interaction force distributions of two concentric carbon nanocones. Finally, a universal potential energy is presented for the carbon nanocones.     

Can an Attractive Potential Increase the Pressure of an Ideal Electron Gas?

We examine the intuitive, classical idea that an interactive system involving commonly used attractive potentials should always have a pressure which is less than that of an ideal Fermi gas. We find that quantum effects are of crucial importance and that, while this idea is normally correct, under certain circumstances, the pressure can exceed that of the ideal Fermi gas.     

On the macroscopic theory of temperature-dependent van der Waals forces

We give a simple derivation of the van der Waals free energy of interaction between two semiinfinite media, including effects of nonzero temperature and retardation. The method, an extension of one used by van Kampen and co-workers at the short-distance and low-temperature limits, considers the free energy of electromagnetic surface modes in the region between the two media. The result is the same as derived by Lifshitz and co-workers using Green's function techniques.     

Many-body study of van der Walls interaction involving lithium and rare-gas atoms and its contribution to hyperfine shifts

Using linked cluster many-body perturbation theory, the frequency-dependent dipole polarizabilitiesa(ω) has been calculated for the lithium atom. The value ofa(ω) at the static limit (169.04a ₀ ³ ) matches well with other available theoretical values and experimental results. These values have been used to calculate the van der Waals constants for interactions of lithium, helium and neon atoms. The values of the van der Waals constants for dipole-dipole interaction in atomic units are −22.9, −44.8, −1465.8, 184950.0, 2011.8, 3896.5, 30.3, 59.0 and 115.1 for Li-He, Li-Ne, Li-Li, Li-Li-Li, Li-Li-He, Li-Li-Ne, Li-He-He, Li-He-Ne and Li-Ne-Ne interactions respectively. Obtaining the suitable response functions for lithium and helium atoms, the long range contribution to Δa(r)/a ₀ in the study of fractional frequency shift in hyperfine pressure and temperature shift measurements is obtained as −541 atomic units.     

论范德瓦尔斯a和b参数与温度的关系

范德瓦尔斯方程中a、b参数是否与温度相关,不但不同文献中的说法互不相同,而且有同一文献前后的结论相互矛盾.本文分析了这个令人迷惑的问题.在热力学中a和b参量被处理为与温度无关,它仅仅在临界点附近有效并可以把范德瓦尔斯方程表述为对应态定律;在更加广泛的温度区间a、b参量和温度有关,但是范德瓦尔斯方程却丧失了其独特性.统计...     

Free-Energy-Based Discrete Unified Gas Kinetic Scheme for van der Waals Fluid

The multiphase model based on free-energy theory has been experiencing long-term prosperity for its solid foundation and succinct implementation. To identify the main hindrance to developing a free-energy-based discrete unified gas-kinetic scheme (DUGKS), we introduced the classical lattice Boltzmann free-energy model into the DUGKS implemented with different flux reconstruction schemes. It is found that the force imbalance amplified by the reconstruction errors prevents the direct application of the free-energy model to the DUGKS. By coupling the well-balanced free-energy model with the DUGKS, the influences of the amplified force imbalance are entirely removed. Comparative results demonstrated a consistent performance of the well-balanced DUGKS despite the reconstruction schemes utilized. The capability of the DUGKS coupled with the well-balanced free-energy model was quantitatively validated by the coexisting density curves and Laplace’s law. In the quiescent droplet test, the magnitude of spurious currents is reduced to a machine accuracy of 10−15. Aside from the excellent performance of the well-balanced DUGKS in predicting steady-state multiphase flows, the spinodal decomposition test and the droplet coalescence test revealed its stability problems in dealing with transient flows. Further improvements are required on this point.     

On the ultraviolet absorption of nitrous oxide and its van der Waals complexes

The possibility of simultaneous characterization of N₂O and N₂O van der Waals complexes in supersonic jet expansions is demonstrated for neat N₂O samples. Room temperature and jet-cooled spectra of the Rydberg transitions 3pπ¹Δ ←← X¹Σ⁺ and 3pσ¹Π ←← X¹Σ⁺ are presented. Theoretical calculations support the assignment of the Rydberg transitions used. For stagnation pressures above 2 bar, a hitherto unreported broad spectral feature at 84 650 cm⁻¹ is observed, where calculations predict absorption of the (N₂O)₂ dimer essentially due to excitation of the 4sσ and 3pπ Rydberg orbitals. Consequences for the use of N₂O as a precursor for O(¹D) atoms in reactive scattering experiments are discussed.