3到3的部分子弹性散射和早期热平衡化

研究了三胶子弹性散射ggg→ggg和三夸克弹性散射qqq→qqq. 证明了包含3→3弹性散射的输运方程的H定理. 输运方程给出了胶子物质热平衡化时间短和夸克物质热平衡化时间长的结果.     

浅谈广义相对论的创立之三 引力场方程的确立与应用

简述了爱因斯坦建立的物质不存在时的引力场方程;介绍了爱因斯坦建立引力场方程的指导思想和方法;讨论了场方程的牛顿近似和水星近日点进动.     

有限温度下的二维暗能量星模型

研究了具有奇异物质作用的二维暗能量星模型,推导出了场方程和星体平衡方程;并获得了一些解析解,计算出了星体质量.另外,还研究了温度对星体质量的影响,发现几种情况下星体总质量都具有上限. 关键词： 暗能量星 奇异物质 有限温度     

热辐射输运问题的隐式蒙特卡罗方法求解

热辐射与物质相互作用及辐射光子在物质中的传输是惯性约束聚变研究中的重要课题. 介绍了基于隐式蒙特卡罗方法的辐射输运方程,在该方程的积分-微分形式基础上,推导了利于蒙特卡罗方法模拟的等价的积分输运方程;基于积分方程设计数值模拟流程,编写三维蒙特卡罗数值模拟程序;针对热辐射输运典型问题及benchmark问题开展了数值实验,计算结果验证了方法的适应性及程序的正确性. 关键词： 热辐射 惯性约束聚变 输运方程 隐式蒙特卡罗     

氯气/BHP液滴化学反应流动一维数值模拟

为研究横向均匀液滴发生器的机理,对Cl₂/He气体横向流过BHP液滴场的物理化学行为建立一维化学反应流动模型.其中气流场按不可压缩假设近似为一维均匀流动;发生于液滴内的化学反应由四种物质的反应扩散方程描述;气相中各种物质浓度由对流扩散方程描述.液滴是这些物质的源或汇,两个模型方程通过此源项相联系.对模型方程作数值求解.结果显示,氯气利用率、单态氧产率及效率与文献所提供的实验结果较为接近,反映了所建模型具备模拟混合气体与BHP液滴反应的基本能力.     

饱和蒸气密度、焓和蒸发潜热的通用对比态推算式

本文提出了新的饱和蒸气密度的通用对比态推算式,并分别以标准沸点下的蒸发潜热和临界温度与标准沸点温度之差为基准,对蒸发潜热和温度无量纲化导出了工质蒸发潜热通用对比态方程,结合饱和液体焓通用对比态方程导出了饱和蒸气焓通用对比态方程,揭示出饱和蒸气焓通用对比态方程为双变量函数,除有温度变量外还包含有表示物质差异的变量。对多种物质的文献值计算比较,以上方程的总的平均绝对偏差分别为0.43％、0.87％和O.35％。     

快度中心区强子物质输运系数和粘滞流体演化

用Chapman-Enskog方法计算了相对论性重离子碰撞快度中心区产生的π介子物质的输运系数,并建立了相应的粘滞流体力学方程,进而讨论了粘滞对π介子物质演化过程的影响.结果表明,粘滞将减缓快度中心区π介子物质的冷却速度.     

奇异物质与暗能量作用的sine-Gordon孤子星模型

研究了具有奇异物质和暗能量作用的sine-Gordon孤子星模型,根据场方程计算了物态方程的解和星体质量,发现物质密度和压强与孤子态和星体质量有关.另外,还对星体平衡和暗能量的稳定性质进行了分析和讨论,结果表明孤子星内部以奇异物质与暗能量的混合态形式存在. 关键词： 奇异物质 暗能量 sine-Gordon孤子星     

求学物理五十年

我们生存于物质世界之中.物理学是研究物质的本质和运动规律的学科.认识客观规律,将之总结和概括,形成物理学基本定律,如大家熟知的牛顿力学三定律,电磁学的麦克斯韦方程组和量子力学的薛定谔方程等.     

弗里德曼模型中静态宇宙条件的两个等效解法

弗里德曼模型是描述当前宇宙的标准模型.其中静态宇宙条件下的物质密度和宇宙常数密度解析关系,对应于无大爆炸区的边界,是宇宙学领域的一个经典问题.经典解法从弗里德曼方程出发,通过消除高斯曲率和标度因子,获得物质密度和宇宙常数密度的相关方程,然后解出.整个推导过程较为曲折复杂.本文给出了一种简单便捷的等效方法.新方法利用哈勃常数的表达式,根据基本物理量的实际取值范围,将问题转化为数学极值问题,从而获得解决.     

耗散旋波介质中的色散关系

应用Maxwell经典电磁理论，结合旋波介质的本构关系，研究耗散旋波介质中光波的色散关系．结果表明，色散关系与介质电导率、旋波因子等因素密切相关．     

Modeling of Influence of Helix Geometry on the Constitutive Parameters of the Chiral Medium

Computations are made to estimate the influence of geometry of the helixes in an artificial chiral medium made by embedding small conducting helives in a lossy isotropic host material on the three constitutive parameters of the medium, by using a proposed model which explicitly includes the first-order effects of reradiation from the helixes, near-field loses and mutual coupling between helixes.     

法拉第手征介质反射电磁波的极化特性研究

从麦克斯韦方程出发严格推导了均匀介质与法拉第手征介质交界面处电磁波反射公式.通过解析的方法讨论了不同极化状态下反射电磁波的极化特性与法拉第手征介质电磁参数之间的关系.针对部分具体实例进行了计算,计算结果与理论预测相符合. 关键词： 法拉第手征介质 反射电磁波 极化特性     

Natural optical activity and liquid crystals

Optical activity of matter is related to the chirality of its constitutive molecules. In liquid crystals, chiral molecules can give rise to superstructures in which the local dielectric tensor rotates in space describing a helix, a fact which greatly enhances the optical activity of the medium. The structures and the optical properties of some helical phases are well-known, as for instance the cholesteric and some chiral smectic phases. For short enough helix pitches, the periodic medium can be considered optically as homogeneous and described by the same constitutive equations used to define the optical properties of solid crystals. Such liquid crystal phases represent an ideal tool to apply the methods, used since a long time in optics, to define homogeneous models for non homogeneous media and to discuss their limits of validity. A brief account is given of the main results recently found in this research area.     

An investigative report on the constructive relations of linear magnetoelectric media

Conventional treatment of linear magnetoelectric media assumes their constitutive relations to have certain symmetries. This assumption is based on static analysis, but is mostly used for alternating fields. Experimental evidence in support of the assumption is certainly incomplete and inadequate, and may be incorrect. The assumption negates the existence of reciprocal biisotropic media, which nevertheless exist in abundance. These and other inadequacies are critically analyzed.     

Hadron Mass and the Properties of Nuclear Matter in the Quark Bag Models

The MIT bag model, chiral bag model and cloudy bag model are revisited. A typical work on the hadron mass calculation by chiral bag model and cloudy bag model is shown in more details with the quark-quark-pi vertex correction and quark self-energy being emphasized. More details are given to review the quark-meson coupling model and its application in nuclear matter. We put forth the Lagrangian of the quark-meson coupling model and studied the possibility of using the model to calculate the hadron mass.     

Generic meminductive characteristics of switched reluctance machines

The meminductive system can be regarded as the generalization of the meminductor.This paper focuses on exploring the generic meminductive characteristics of the switched reluctance machine(SRM).The dynamical equations of SRM systems are derived and discussed in comparison with the typical constitutive relation equations of the meminductive system.Memory ability and pinched hysteresis loop(PHL) are taken as the indicative fingerprints to draw forth the theoretically comparative analysis.Based on the theoretical analysis,in addition to simulation and experimental confirmation,it can be concluded that from the viewpoint of circuit,SRM can be considered as a generic meminductive system.     

A Brief Review of Elasticity and Viscoelasticity for Solids

There are a number of interesting applications where modeling elastic and/or viscoelastic materials is fundamental, including uses in civil engineering, the food industry, land mine detection and ultrasonic imaging. Here we provide an overview of the subject for both elastic and viscoelastic materials in order to understand the behavior of these materials. We begin with a brief introduction of some basic terminology and relationships in continuum mechanics, and a review of equations of motion in a continuum in both Lagrangian and Eulerian forms. To complete the set of equations, we then proceed to present and discuss a number of specific forms for the constitutive relationships between stress and strain proposed in the literature for both elastic and viscoelastic materials. In addition, we discuss some applications for these constitutive equations. Finally, we give a computational example describing the motion of soil experiencing dynamic loading by incorporating a specific form of constitutive equation into the equation of motion.     

A Study of One S- and One P-Wave Heavy Meson Interaction in a Chiral Quark Model

The analytical forms of the interaction potentials between one pseudo-scalar/vector and one scalar/tensor/axial-vector heavy mesons are deduced based on a chiral quark model. Our results explicitly show the attractive property between the two heavy mesons. Consequently, a series of possible molecular states are obtained. It is expected that our study might shed some light on the popular discussions of the newly observed XYZ states.     

Electrodynamics and Spacetime Geometry: Foundations

We explore the intimate connection between spacetime geometry and electrodynamics. This link is already implicit in the constitutive relations between the field strengths and excitations, which are an essential part of the axiomatic structure of electromagnetism, clearly formulated via integration theory and differential forms. We review the foundations of classical electromagnetism based on charge and magnetic flux conservation, the Lorentz force and the constitutive relations. These relations introduce the conformal part of the metric and allow the study of electrodynamics for specific spacetime geometries. At the foundational level, we discuss the possibility of generalizing the vacuum constitutive relations, by relaxing the fixed conditions of homogeneity and isotropy, and by assuming that the symmetry properties of the electro-vacuum follow the spacetime isometries. The implications of this extension are briefly discussed in the context of the intimate connection between electromagnetism and the geometry (and causal structure) of spacetime.