变形对称双阱势

利用变形双曲函数,将对称双阱势推广为变形对称双阱势模型.证明了该势模型是五参量指数型势模型的特例.运用超对称WKB近似和五参量指数型势模型的能谱公式,获得了变形对称双阱势模型的能谱公式.     

Interaction of Double Sine-Gordon Solitons with External Potentials:an Analytical Model

Interaction of double sine-Gordon solitons with a space dependent potential wall as well as a potential well is investigated by employing an analytical model based on the collective coordinate approach.The potential is added to the model through a suitable nontrivial metric for the background spacetime.The model is able to predict most of the features of the soliton-potential interaction.It is shown that a soliton can pass through a potential barrier if its velocity is larger than a critical velocity which is a function of the initial soliton conditions and also characters of the potential.It is interesting that the solitons of the double sine-Gordon model can be trapped by a potential barrier and oscillate there.This situation is very important in applied physics.The soliton-well system is investigated by using the presented model.Analytical results are also compared with the results of the direct numerical solutions.     

一种新的航天器外露介质充电模型

为综合考虑高能电子辐射与周围等离子体对航天器外露介质充电的影响,在航天器内带电模型的基础上,通过添加边界充电电流来考虑等离子体与航天器介质表面的相互作用,并统一参考电位为等离子体零电位,建立了航天器外露介质充电模型,给出了新模型的一维稳态解法,并与表面充电模型和深层充电模型进行了对比分析.结果表明:新建模型能够综合考虑表面入射电流、深层沉积电流和传导电流对充电的耦合作用过程,实现外露介质表面和深层耦合充电计算,有利于全面评估航天器外露介质的充电问题.     

Bursting characteristics of a neuron model based on a concept of potential with active areas

We present various bursting wave forms that are obtained from a simple model of the Hodgkin-Huxley type. The model is a typical example whose characteristics can be discussed through the concept of potential with active areas. A potential function is able to provide a global landscape for dynamics of a model, and the dynamics are explained in relation to the disposition of the active areas on the potential. We obtain the potential functions and the active areas for the Hindmarsh-Rose model, the Morris-Lecar system, and the Hodgkin-Huxley system, and hence, we are able to discuss the common properties among these models based on the concept of potential with active areas.     

具有加权顾前势的交通流模型

交通流随机行为的研究对于理解交通系统的内在演化规律具有重要作用. 基于元胞自动机模型和顾前势模型, 提出了一种考虑加权顾前势的交通流模型. 通过引入顾前势加权系数及对越靠近自身车辆的相互作用势赋予越大的权重, 使得建模过程更符合实际交通中司机根据前面车辆和环境情况进行随机决策的过程. 通过数值模拟, 再现了丰富的高密度交通行为. 仿真结果表明, 加权系数在高密度情况下作用明显, 更有利于在保持较高交通密度的同时, 具有较高的交通流量和道路通行能力. 关键词： 交通流 顾前势 随机模型 加权     

SF6在惰性气体中输运性质的理论研究

利用Tang-Toennies势模型(以下简称TT势),计算了(Ne、Ar、Kr、Xe)-SF6相互作用势,在此基础上得到了SF6在惰性气体中的扩散系数,粘滞系数和热传导系数,通过相互作用势与M3SV势比较及输运性质与实验值的比较,说明了TT势模型是一种简单、可靠的势模型。     

LONG RANGE POTENTIAL BETWEEN NUCLEONS

Using hybrid chiral bag model, one gets a model which can be used to calculate potential between two separate nucleons. It is shown that the obtained results, centre and tensor potential, are compatible with phenomenological potentials such as Hamada-Johnston potential and Reid potential. Whether the bag radius for a free nucleon is different from that of a nucleon in the nuclear matter is discussed.     

Three-body effects in hydrogen fluoride: survey of potential energy surfaces

The potential energy surface for trimers of hydrogen fluoride is examined for multiple arrangements of the three-molecule cluster. Several established approaches to model the potential energy are examined, including a strictly pairwise additive potential, an established polarizable potential model, another, strictly three-body polarizable model, and a three-body potential recently fitted to accurate ab initio calculations. These potential surfaces are compared to MP2/6-311++G** and SCF/6-311++G**ab initio calculations performed here for each configuration. In each case the overall trimer potential is examined, as well as the three-body contribution to it (obtained by subtracting the sum of the interactions taken pairwise). The effective pair potential has some correspondence to the ab initio calculations, although it generally displays a shallower minimum energy. The established polarizable model has a more repulsive core that compensates for a deeper attractive well that it has adopted to better describe phase-coexistence data. In contrast, the new three-body polarizable model shows better correspondence with the ab initio potential-energy surface.     

The nonrelativistic limit of the relativistic point coupling model

We relate the relativistic finite range mean-field model (RMF-FR) to the point-coupling variant and compare the nonlinear density dependence. From this, the effective Hamiltonian of the nonlinear point-coupling model in the nonrelativistic limit is derived. Different from the nonrelativistic models, the nonlinearity in the relativistic models automatically yields contributions in the form of a weak density dependence not only in the central potential but also in the spin-orbit potential. The central potential affects the bulk and surface properties while the spin-orbit potential is crucial for the shell structure of finite nuclei. A modification in the Skyrme-Hartree-Fock model with a density-dependent spin-orbit potential inspired by the point-coupling model is suggested.     

Simple pair potential model for real fluids. III. Parameter determination and a revised model for spherical molecules

A method combining macroscopic data with atomic structure constants for determination of the parameters of simple potential models is discussed. A revised hybrid potential model, MMH, whose hard core diameter and location of the potential minimum are determined a priori from the atomic structure is proposed. Calculations of the second and third virial coefficients and the viscosity coefficient indicate that the MMH model may be a reliable potential superior to all other simple potential models.     

Binomial potential of the electron-proton interaction as an alternative to the Coulomb law

It is shown that a solution of the classical Kepler problem with a binomial potential explains the stationary orbits of the hydrogen atom, its discrete spectrum, and trajectories of scattered electrons with energies from several electron-volts to relativistic values. The Schrodinger equation with the binomial potential takes the form of a classical wave equation. Hence, the binomial potential is a more appropriate model for understanding atomic phenomena than the model based on the Coulomb potential.     

遗传算法优化BaTiO3壳模型势参数

本文应用灵敏度分析方法从BaTiO₃壳模型众多参数中找到对结构和性能影响最为明显的主要参数,将次要参数常数化,降低优化问题的维数;然后应用遗传算法对主要参数进行优化.优化结果表明,势参数可以较准确地模拟结构、力学性能以及相变过程. 关键词： 壳模型 灵敏度分析 遗传算法     

Efficient compact model for calculating the surface potential of carbon-nanotube field-effect transistors using a curve-fitting method

This paper presents an analytical method to compute the surface potential of ballistic metal-oxide semiconductor field-effect transistor (MOSFET)-like carbon-nanotube field-effect transistors (CNFETs). The proposed compact model considers the surface potential as functions of the carbon-nanotube diameter, gate insulator thickness, gate voltage and drain voltage. One of the advantages of this model is that there is no need to refer to the numerical model to recalculate the surface potential each time nanotube diameter or insulator thickness is changed. Instead of using a constant smoothing parameter regardless of the device size and applied bias voltages, a parameter calculated for the specific situations is employed to provide the simulation results with higher accuracy. The validity of the proposed model was verified by comparing the simulated output characteristics of three CNFETs with those of the numerical model and the previous compact model.     

Stability of the scalar potential and symmetry breaking in the economical 3-3-1 model

A detailed study of the criteria for stability of the scalar potential and the proper electroweak symmetry breaking pattern in the economical 3-3-1 model, is presented. For the analysis we use and improve a method previously developed to study the scalar potential in the two-Higgs-doublet extension of the standard model. A new theorem related to the stability of the potential is stated. As a consequence of this study, the consistency of the economical 3-3-1 model emerges.     

电流驱动磁化翻转中的热效应

从理论上研究了电流驱动磁开关中的热效应,在Neel-Brown弛豫时间理论和Li等的有效温度的工作基础上作了改进.在对称系综模型的Landau-Lifshitz-Gilbert和Fokker-Planck方程的基础上,分析了电流驱动磁动力学开关过程和电流引起磁势能的变化,提出一个新的电流感应磁势垒降低模型.新模型是非线性的,与Li等的有效温度模型不同.在此模型的基础上,讨论了开关临界电流对温度、开关时间的依赖关系,理论与实验相符合.对电流引起的样品温升的实验曲线进行了修正,实验结果与文中的非线性势垒降低模 关键词： 热效应 自旋传输矩 Neel-Brown弛豫时间 Fokker-Planck方程     

Proton-nucleus optical model potential at low energies—a review

Ever since it was proposed more than three decades ago, the nuclear optical model has been very successful in interpreting a large body of nucleon-induced nuclear reaction data in terms of a complex nucleon-nucleus potential. Rapid progress both in the experimental measurements and the theoretical developments in the last two decades has led to a better understanding of this nucleon-nucleus optical potential. From the parameter-fitting phenomenological stage, the optical model has come a long way and it is now possible to calculate the nucleon-nucleus optical potential in a reasonable way starting from the fundamental nucleon-nucleon interaction. Excellent reviews on various aspects of the optical model exist in the literature for proton energies above 10 MeV. The present article is an attempt to review comprehensively the status of the proton-nucleus optical potential at low proton energies, below the Coulomb-barrier, for target nuclei with mass numbers lying between 40 and 130. The sets of phenomenological optical potential derived mostly from (p, n) reaction data are reviewed and their applicabilities discussed. The neutron-nucleus optical model is referred to wherever it is relevant. Microscopic calculations for one case is carried out and compared with the corresponding phenomenological values.     

利用电子结构数据拟合H2分子的电子壳模型势函数参数

电子壳模型势函数在离子晶体的原子级计算机模拟中有广泛应用,其势参数主要通过拟合晶体的实验数据或电子结构数据得到.提出了通过拟合双原子分子的量子化学从头计算电子结构数据来获得该势函数的方法,并由H2分子的电子结构数据建立了H原子间的电子壳模型势函数.此外,还应用该势函数对H+2分子离子进行了计算.该势函数拟合方案更适合于共价键型的分子.     

An effective pair potential for liquid semiconductor, Se: Structure and related dynamical properties

The effective pair potential of liquid semiconductor Se is extracted from its experimental structure factor data using an accurate liquid state theory and this shows important basic features. A model potential incorporating the basic features of the structure factor extracted potential is suggested. This model potential is then used to describe through low-order perturbation theory, the structure and related dynamical properties like self-diffusion coefficient and shear viscosity of this complex liquid over a wide range of temperatures.     

Optical-model analysis of exotic atom data: (II). Antiprotonic and sigma atoms

Data for antiprotonic and sigma atoms are fitted using a simple optical model with a potential proportional to the nuclear density. The potential strength can be related to the free hadron-nucleon scattering length using a model due to Deloff. A good overall representation of the data is also obtained with a black-sphere model.