计算范德瓦尔斯气体体积的简单方法

范德瓦尔斯方程是体积Ｖ的三次方程．本文提供一种用计算机迭代求解体积的方法,此法能快速、精确地迭代计算,且能根据不同要求进行快速迭代．用计算机迭代计算的方法也可对其他物理问题的函数进行近似计算．     

多方过程几种定义说法等效性的证明

本以范德瓦尔斯气体为例，证明了在Cv为常数的条件下多方过程几种定义说法的等效性，并给出了范氏气体多方过程的功容定义，最后指出功容为常量才是多方过程最基本的特征。     

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.统计物理文献把a和b参量处理成为位力展开的一种拟合方程,发现一般情况下两个参数都依赖于温度,仅仅在特殊情况下和温度无关,以说明对应态定律成立的条件.热力学和统计物理关于a和b参量是否依赖于温度相互矛盾的表述,源于这两个理论中范德瓦尔斯状态方程适用范围不同.     

范德瓦尔斯气体的卡诺循环效率

以范德瓦尔斯气体为工作物质推导出的卡诺循环效率,只与热源的温度有关,与工作物质是否是理想气体无关.     

范德瓦尔斯气体的气压公式

将大气近似为范德瓦尔斯气体,用多方过程取代等温过程,推导出范德瓦尔斯气体处于多方过程时的气压公式,该式是对理想气体恒温气压公式的一种很好的修正.     

等面积法则证明浅谈

本文对等面积法则证明过程中的佯谬问题进行了分析，认为该现象是由于等面积法则与范德瓦尔斯理论之间的不自洽造成的，并给出了一种在普物教学中适用的证明方法。     

范德瓦尔斯方程的几点探析

分析了学生在范德瓦尔斯方程学习中容易产生误解或者忽视的几个重要问题,以加强学生对范德瓦尔斯方程的准确理解.     

修正Poschl—Teller势的Schrodinger方程束缚态的精确解

将修正Ｐｏｓｃｈｌ－Ｔｅｌｌｅｒ势的Ｓｃｈｒｏｄｉｎｇｅｒ方程作自变量双曲函数变换，使其转化为普遍的ａｓｓｏｃｉａｔｅｄ－Ｌｅｇｅｎｄｒｅ方程，用级数法解此方程，得到用普遍的ａｓｓｏｃｉａｔｅｄ－Ｌｅｇｅｎｄｒｅ多项式表示的修正Ｐｏｓｃｈｌ－Ｔｅｌｌｅｒ势的束缚态的归一化波函数，文献［１－５］中的有关结果都作为特例包含在本文的一般结论之中。     

高温高密度氢（氘）的物态方程——离解效应研究

 高温高压下流体氢将发生离解化学反应，形成具有相互作用的氢分子和氢原子混合体系，此时粒子间的相互作用复杂。利用单组分流体近似的范德瓦尔斯混合模型，将混合物粒子间的相互作用等效为单组分粒子间相互作用，从而简化了对体系的统计热力学处理；并由自由能函数极小化确定化学平衡时各组分含量、体系的内能、压强。研究了温度在10 000 K以下、密度在0.6 g/cm³以下（相应摩尔体积大于3.3 cm³/mol）区间的热致离解和压致离解现象对流体氢（氘）状态方程的影响。所得结果与双组分流体变分理论计算以及第一原理的分子动力学模拟、蒙特卡罗模拟结果以及二级轻气炮实验数据进行了比较，它们之间的一致性表明：用单组分流体近似的范德瓦尔斯混合模型处理氢（氘）分子的离解区域的物态方程是成功的。     

以范德瓦耳斯气体为工质的3种热机循环效率

利用热力学的普遍理论推导了范德瓦尔斯气体热力学函数的表达式,再求出绝热过程和3种等值过程中功和热量的表达式.在此基础上,研究了斯特林循环、奥拓循环和狄塞尔循环的功和效率,并计算和分析了3种循环效率随各种参量变化的关系.     

动力学压缩真空中的Van der Waals力

基于参数动力学过程产生的压缩效应,利用Millonni源理论方法研究了 动力学压缩真空中Van der Waals力的性质及其与真空压缩的关系。所得结果表明：Van der Waals力的性质依赖于真空压缩的程度;在一定的临界条件下,Van der Waals力由通常的 吸引性作用转化为排斥性作用。当压缩系数为零时,所得结果与通常文献完全一致。     

Infrared photodetectors based on graphene van der Waals heterostructures

We propose and evaluate the graphene layer (GL) infrared photodetectors (GLIPs) based on the van der Waals (vdW) heterostructures with the radiation absorbing GLs. The operation of the GLIPs is associated with the electron photoexcitation from the GL valence band to the continuum states above the inter-GL barriers (either via tunneling or direct transitions to the continuum states). Using the developed device model, we calculate the photodetector characteristics as functions of the GL-vdW heterostructure parameters. We show that due to a relatively large efficiency of the electron photoexcitation and low capture efficiency of the electrons propagating over the barriers in the inter-GL layers, GLIPs should exhibit the elevated photoelectric gain and detector responsivity as well as relatively high detectivity. The possibility of high-speed operation, high conductivity, transparency of the GLIP contact layers, and the sensitivity to normally incident IR radiation provides additional potential advantages in comparison with other IR photodetectors. In particular, the proposed GLIPs can compete with unitravelling-carrier photodetectors.     

Ar-D232S复合物的转动光谱理论研究

对Ar-D₂³²S转动光谱进行了理论研究．该体系的分子间势能面是由最近报道的Ar-D₂³²S体系的从头算三维势能面转换而来．通过采用径向离散变量表象与角度有限基组表象相结合的方法和Lanczos算法,计算了复合物的转动能级和波函数．结果表明,理论计算得到的转动跃迁频率和结构参数与实验值吻合较好     

Millimeter-wave investigation, simplified interpretation of the fourfold rotational spectrum, and dynamics of the internal motions of acetaldehyde-argon

The rotational spectra of the acetaldehyde-argon van der Waals complex have been measured by free jet absorption millimeter-wave spectroscopy in the frequency range 60-78 GHz. Each rotational transition is split into four hyperfine component lines, which is evidence of the occurring of two different internal motions. The splittings have been interpreted in terms of a coupled Hamiltonian that precisely determines the separation of energy levels due to the tunneling of the rare gas atom between two equivalent minima, while the information on the barrier to internal rotation of the methyl group is obtained from the pattern of the component A-E lines due to this motion. The interaction of the rare gas atom with the acetaldehyde moiety is reflected in a reduction of the V₃ barrier to internal rotation in going from the molecule to the weakly bound complex of about 20%. The barrier to the Ar tunnelling has been estimated to be 26 cm⁻¹.     

Infrared detection and photon energy up-conversion in graphene layer infrared photodetectors integrated with LEDs based on van der Waals heterostructures: Concept,device model,and characteristics

We propose the concept of the infrared detection and photon energy up-conversion in the devices using the integration of the graphene layer infrared detectors (GLIPs) and the light emitting diodes (LEDs) based on van der Waals (vdW) heterostructures. Using the developed device model of the GLIP-LEDs, we calculate their characteristics. The GLIP-LED devices can operate as the detectors of far- and mid infrared radiation (FIR and MIR) with an electrical output or with near-infrared radiation (NIR) or visible radiation (VIR) output. In the latter case, GLIP-LED devices function as the photon energy up-converters of FIR and MIR to NIR or VIR. The operation of GLIP-LED devices is associated with the injection of the electron photocurrent produced due to the interband absorption of the FIR/MIR photons in the GLIP part into the LED emitting NIR/VIR photons. We calculate the GLIP-LED responsivity and up-conversion efficiency as functions the structure parameters and the energies of the incident FIR/MIR photons and the output NIR/VIR photons. The advantages of the GLs in the vdW heterostructures (relatively high photoexcitation rate from and low capture efficiency into GLs) combined with the reabsorption of a fraction of the NIR/FIR photon flux in the GLIP (which can enable an effective photonic feedback) result in the elevated GLIP-LED device responsivity and up-conversion efficiency. The positive optical feedback from the LED section of the device lead to increasing current injection enabling the appearance of the S-type current-voltage characteristic with a greatly enhanced responsivity near the switching point and current filamentation.     

重力场中的范德瓦耳斯气体

将地球大气近似为重力场中的范德瓦耳斯气体,在绝热过程近似下导出了大气温度、压强随高度的分布,并与理想气体近似结果进行了比较分析.     

Axisymmetric vibration of single-walled carbon nanotubes in water

A double shell-Stokes flow model is developed to study the axisymmetric vibration of single-walled carbon nanotubes (SWCNTs) immerged in water. In contrast to macroscopic solid-liquid system, a submerged SWCNT is coupled with surrounding water via the van der Waals interaction. It is shown that this unique feature substantially reduces viscous damping of the axisymmetric radial, longitudinal and torsional vibrations and significantly up-shifts the frequency of the radial vibration of an SWCNT. The study offers a theoretical explanation for the experimental observation and molecular dynamics simulations available in particular cases, and provides an efficient modelling tool and useful guidance for the study of the general dynamic behaviour of SWCNTs in a fluid.