基于热质理论的Hamilton原理

基于热质理论,类比经典力学,给出了热质运动遵循的Hamilton原理以及相应的导热Lagrange方程.由于考虑了热质动能,热质运动的Hamilton原理有望应用于非Fourier效应的讨论,在忽略热质动能时,回归到Fourier热学.应用Lagrange方程对含内热源一维瞬态导热问题进行了近似求解,计算结果与解析解符合较好.从分析力学的角度对传热理论以及热学与力学的统一做了新的阐释,指出了现有文献中采用分析力学方法讨论导热问题时存在的某些不足,为导热问题的近似求解提供了新的思路,同时也说明了热质和热质能     

热质的运动和传递-最低热质能耗散原理和热质运动方程

过增元基于质能方程提出了热质的概念.在非平衡热力学中,存在最低能量耗散原理,根据该原理可以导出热传导,扩散及粘性流动等不可逆输运过程的方程式.当采用热质模型对传热现象进行描述时,发现热质的运动也满足最小作用量原理:最低热质能耗散原理,根据该原理可以推导得出热质运动的动量守恒方程。     

基于热质理论的热波传递现象研究

基于热质的概念应用牛顿力学原理建屯了热质输运的控制方程,推导得到了普适的导热定律.在惯性力可以忽略时它即退化为傅立叶导热定律,反映出非傅立叶导热现象的本质是热质的惯性引起的.当热流和温度对空间的惯性以及温度对时间的惯性可以忽略时,所得到的导热定律可以退化为CV模型.对热波传递的数值分析表明:当热扰动和热流都比较小时,热流在空间加速的惯性可以忽略,基丁热质理论的热波方程和CV模型符合得很好;但是,在描述较大的热扰动时,由于热流的空间加速惯性不能够被忽略,CV模型的结果在两个温度波峰叠加时会出现负温度的非物理现象,而基于热质理论的普适导热定律的结果则克服了这一缺陷.     

热质的运动与传递——热质和热子气

基于爱因斯坦的狭义相对论的质能关系建立了热质的概念。物体的热能所对应的动质量就是热质。提出了热子的概念和热子气模型。采用气体分子动理论导得了热子气的压力(热质压力)和热子气的状态方程。热子气中的热质压力梯度是热量(热子气)运动的推动力。     

考虑相变的热弹塑性本构方程及其应用

将在热加工及热处理过程中发生相变的材料考虑为热弹塑性的多相混合物,基于连续介质物理学及含内变量的不可逆热力学,推导出考虑相变的热弹塑性本构方程.根据一组不同温度水平下的高温短时拉力试验,确定本构方程中的材料参数及其随温度的变化关系.同时,提出了考虑相变的热传导方程和计及应力影响的相变动力学方程.基于这些方程编制相应有限元分析程序,用其分析计算了1Cr12WMoV不锈钢管通的焊接残余应力分布.计算所得结果与通过X射线衍射测试的实验结果具有较好的一致性.关键词：相变热弹塑性本构方程焊接     

“从爱因斯坦质能关系式推出勾股定理”之荒谬

一本数学教科书提出并“证明”勾股定理可以用爱因斯坦质能关系式推导出来。教科书的编写者混淆了爱因斯坦少年时对勾股定理的简洁而睿智的纯数学推导,与多年后提出的著名的物理大发现——质能关系式。科学和教育界类似的荒谬贻害深远,必须予以澄清。     

基于热质理论的广义热弹性动力学模型

具有微尺度传热特征的超常传热过程中,热流矢与温度梯度之间存在延迟效应,且热流的运动受到空间效应的影响.基于热质概念的普适导热定律,结合Clausius不等式和Helmholtz自由能公式,构建了计及热流矢和温度对时间和空间惯性效应的广义热弹性动力学模型,推导了各向同性材料超常传热行为的热弹性控制方程组.通过与已有广义热弹性动力学模型进行对比分析可得,当热流密度不大的条件下,热流矢与温度对空间的惯性效应可忽略时,基于热质概念的广义热弹性模型可分别退化为L-S,G-L和G-N的模型;对于尺度微观、稳态导热条件时,热流矢与温度对空间的惯性效应不可忽略,此时导热系数将受到热质运动惯性效应的影响,利用所建模型可揭示稳态导热时呈现的非傅里叶现象,并可避免基于已有广义模型得到的导热系数随结构特征尺寸变化的非物理现象.     

沃尔顿：从实验家到大先生

相对论是爱因斯坦对人类做出的最伟大科学贡献,特别是脍炙人口的质能方程.但世人却对用实验证明爱因斯坦质能方程的物理学家们不甚了解,直到曼哈顿工程造出原子弹才知晓.其实早在1932年,来自爱尔兰的沃尔顿和来自英国的科克罗夫特在分裂原子的过程中,他们成功通过实验的方式证实了爱因斯坦质能方程的等价性.沃尔顿和科克罗夫特两人由于1932年“用人工加速粒子产生原子核嬗变”这项伟大成就共享了1938年的休斯勋章以及1951年的诺贝尔物理学奖.相比于科克罗夫特的热情与外向,沃尔顿为人低调温和、谦虚内敛,也许正是因为他安静的性格,使得许多人忽视了他杰出的科研成就与卓越的社会贡献.本文以质能方程验证90周年为契机,向广大读者详细全面地介绍这位低调却备受爱尔兰人民爱戴的物理学家——沃尔顿.     

热质的运动与传递-热波

根据爱因斯坦狭义相对论,热量具有其对应的相对论质量,并且引入了描述热质(热量)运动的连续方程、动量方程.本文根据热质(热量)运动控制方程组,导出了热质(热量)的波动方程,证明了热量具有波动的传递方式,当热质动能与热质的耗散在同一量级时,得到了有限的热波传播速度.分析了热波产生的物理机制.基于热质理论的热波模型与CV模型进行了比较,指出了CV模型在物理上的缺陷.最后对一维热波的传播过程进行了数值模拟,给出了超快速导热过程的物理图像.     

相对论质速关系和质能关系的一种推导

给出了一种不直接使用洛伦兹变换关系而得到相对论动力学的质速关系和质能关系的新推导,质速关系和质能关系将不再需要直接与光速有关而是与更一般的运动速度上限vm有关.     

基于拉格朗日方程的含源导热问题分析

应用基于热质理论的拉格朗日方程对含内热源一维瞬态导热问题进行了近似求解,计算结果与精确解吻合较好;同时指出了现有文献中采用分析力学方法讨论导热问题时存在的某些不足.本文工作表明了基于热质理论用分析力学观点研究导热间题这一方法的有效性,也从一个侧面说明热质和热质能等热学新概念具有一定的合理性.     

From Classical Hamiltonian Flow to Quantum Theory: Derivation of the Schrödinger Equation

It is shown how the essentials of quantum theory, i.e., the Schrödinger equation and the Heisenberg uncertainty relations, can be derived from classical physics. Next to the empirically grounded quantisation of energy and momentum, the only input is given by the assumption of fluctuations in energy and momentum to be added to the classical motion. Extending into the relativistic regime for spinless particles, this procedure leads also to a derivation of the Klein-Gordon equation. Comparing classical Hamiltonian flow with quantum theory, then, the essential difference is given by a vanishing divergence of the velocity of the probability current in the former, whereas the latter results from a much less stringent requirement, i.e., that only the average over fluctuations and positions on the average divergence be identical to zero.     

Comparison of Kinetic Theory and Hydrodynamics for Poiseuille Flow

Comparison of particle (DSMC) simulation with the numerical solution of the Navier–Stokes (NS) equations for pressure-driven plane Poiseuille flow is presented and contrasted with that of the acceleration-driven Poiseuille flow. Although for the acceleration-driven case DSMC measurements are qualitatively different from the NS solution at relatively low Knudsen number, the two are in somewhat better agreement for pressure-driven flow.     

From superoperator formalism to nonequilibrium Thermo Field Dynamics

Emphasizing that the specification of the representation space or the quasiparticle picture is essential in nonequilibrium quantum field system, we have constructed the unique unperturbed representation of the interaction picture in the superoperator formalism. To achieve it, we put the three basic requirements (the existence of the quasiparticle picture at each instant of time, the macroscopic causality and the relaxation to equilibrium). From the resultant representation follows the formulation of nonequilibrium Thermo Field Dynamics (TFD). The two parameters, the number distribution and excitation energy, characterizing the representation, are to be determined by the renormalization condition. While we point out that the diagonalization condition by Chu and Umezawa is inconsistent with the equilibrium theory, we propose a new renormalization condition as a generalization of the on-shell renormalization on the self-energy which derives the quantum transport equation and determines the renormalized excitation energy.     

Some New Solutions Derived From the 5-Dimensional Theory—The New Methods of Creating Solutions

Application of the 5-dimensional coordinate transformations in the 5-dimensional theory lead us to some new solutions for the 4-dimensional Einstein–Maxwell equations and the relevant scaler equation. From the Kerr solution we derive the corresponding solution. And we propose a new method to solve the usual 4-dimensional Einstein–Maxwell equations and the scalar equation, illustrating by three examples.     

Kinetic theory of granular shear flow: Constitutive relations for the hard-disk model

A kinetic theory for the constitutive Theological relations of rapid granular shear flow of hard circular disks, characterized by a coefficient of restitutione and a surface roughness coefficient, is formulated. From a set of general constitutive equations for single-particle dynamical variables, the approximate expressions for the limit of small and large dimensionless dissipative parameterR _t are obtained. HereR _t is defined as the ratio /, where is the fluctuation of translational velocity from the mean flow velocity, is the diameter of a disk, and is the shear rate. At smallR _t the theoretical predictions can be compared with exact computer simulation results of granular dynamics that are also reported. The agreement between theory and simulation is better than expected; the present theory is accurate up to high packing density in this region ofR _t .     

5D Dirac Equation in Induced-Matter Theory

According to an induced-matter approach, Liu and Wesson obtained the rest mass of a typical particle from the reduction of a 5D Klein–Gordon equation to a 4D one. Introducing an extra-dimension momentum operator identified with the rest mass eigenvalue operator, we consider a way to generalize the 4D Dirac equation to 5D. An analogous normal Dirac equation is gained when the generalization reduces to 4D. We find the rest mass of a particle in curved space varies with spacetime coordinates and check this for the case of exact solitonic and cosmological solution of the 5D vacuum gravitational field equations.     

单层石墨烯片的非线性板模型

基于实验得到的非线性本构关系和板理论,本文建立了包含三次及五次非线性项的单层石墨烯片的板动力学模型.针对四边简支矩形板,使用Ritz法研究了在板中点作用集中力时的静力弯曲,以及边界均匀受力时的静力屈曲问题.结果显示,基于非线性本构关系的板模型能很好的描述单层石墨烯片的力学行为,而且模型中的五次非线性项对结构的弯曲变形有显著影响.