关于开尔文表述和克劳修斯表述的等价性的一点讨论

讨论了热力学第二定律的开尔文表述和克劳修斯表述的等价性的一个问题     

一维格子自旋开链的Lax表述

提出了量子完全可积格子自旋开链的Ｌａｘ表述．特别地，明显构造了具有一般边界项的一维Ｈｅｉｓｅｎｂｅｒｇ ＸＸＺ开链的Ｌａｘ对，从而给出了其量子可积性的直接证明 关键词：     

对热力学第二定律开尔文表述的一点讨论

本文指出，热力学第二定律的开尔文表述以及Ｒａｍｓｅｙ、Ｌａｎｄｓｂｅｒｇ等人对它所作的改述都不够完备，并提供了一种完备的表述。同时指出，开尔文表述只有作了完备的改述后，才与作了完备改述的克劳修斯表述等价。     

相对论的几何表述

通俗地简介了微分几何的入门知识，对狭义相对论几何表述的基本概念作了介绍，较详尽用四维几何语言剖析了“尺缩”“钟慢”和双子效应，地其中的某些误解作了澄清，还简介了广义相对论的入门知识，重点说明为什么引力是时空弯曲的表现，在澄清对等效原理的误解上也略费了笔墨，简介了狭义相对论和广州相对论的划界标准，明确指出了双子佯谬纯属狭义相对论范畴。     

妙题共欣赏 疑义相与析——中考物理命题摭谈

中考物理命题,有巧妙设置,也有疏忽失误与表述欠科学合理之处,本文通过具体的中考试题加以赏析与阐述.     

物理教学现代化与现代物理教学化

说明基础物理教学现代化与现代物理教学化、物理规律的表述方式密切相关，比较了力学的三种表述方式，讨论《新概念物理教程·力学》的创新之处及不足。     

5 kVA高温超导变压器双饼线圈不同有限元模型对比分析

本文基于5 kVA 高温超导变压器的高压绕组双饼线圈, 运用有限元软件, 完成了均质化建模. 相比于全模型, 采用均质化模型不仅不影响计算精度, 而且大大减少了计算时间, 同时能够快速有效地计算出双饼线圈的磁场分布、 电流密度分布以及线圈交流损耗. 为了验证双饼线圈有限元计算模型的正确性, 本文进行了 H 方程全模型、H 方程均质化模型、T-A 方程全模型及T-A 方程均质化模型下的对比仿真分析. 仿真结果的一致性表明了双饼线圈有限元计算模型的正确性. 本文为后续基于T-A 方程下高温超导变压器均质化模型的研究提供了参考.     

Quantum Effects of an Extra Compact Dimension on the Wave Function of the Universe

We extended the direct quantum approach of the standard FRW cosmology from 4D to 5D and obtained a Hamiltonian formulation for a wave-like 5D FRW cosmology. Using a late-time approximation we isolated a y-part from the full wave function of the 5D Universe. Then we found that the compactness of the fifth dimension y yields a quantized spectrum for the momentum P ₅ along the fifth dimension, and we have shown that the whole space-part of the wave function of the 5D Universe satisfies a 2D Schrödinger equation.     

The transport equation in optically thick media

The photon transport equation is transformed into a new form by considering the deviation of the specific intensity from the local equilibrium field. We call the new form of the equations the difference formulation. It is rigorously equivalent to the original transport equation. The difference formulation is particularly suited for thick media, where the radiation field approaches local equilibrium and the deviations from the Planck distribution are small. The difference formulation for photon transport also clarifies the diffusion limit. Preliminary results confirm our expectations of a substantial advantage for accurate numerical calculations in optically thick media.     

On hamiltonian formulation of cosmologies

Novello et al [1,2] have shown that it is possible to find a pair of canonically conjugate variables (written in terms of gauge-invariant variables) so as to obtain a Hamiltonian that describes the dynamics of a cosmological system. This opens up the way to the usual technique of quantization. Elbaz et al [4] have applied this method to the Hamiltonian formulation of FRW cosmological equations. This note presents a generalization of this approach to a variety of cosmologies. A general Schrödinger wave equation has been derived and exact solutions have been worked out for the stiff matter era for some cosmological models. It is argued that these solutions appear to hint at their possible relevance in the early phase of cosmological evolution.     

Algebraic Formulation of Quantum Decoherence

An algebraic formalism for quantum decoherence in systems with continuous evolution spectrum is introduced. A certain subalgebra, dense in the characteristic algebra of the system, is defined in such a way that Riemann–Lebesgue theorem can be used to explain decoherence in a well defined final pointer basis.     

Phase Formulation and Exact Solutions for the Relativistic Klein-Gordon Field with a Time-Dependent Hamiltonian

On the basis of the phase formulation, we find the quantum and classical exact solutions and corresponding total phases for the Klein-Gordon (KG) field with a time-dependent Hamiltonian. The total phase includes both the dynamical and geometric phases (Abaronov-Anandan phase). The connection between the quantum and classical solutions is then obtained. From this connection, we discuss the condition under which the geometric phase for the KG field can be defined.     

Adler-Bardeen theorem in path integral formulation

The higher order contributions to Jacobian in Fujikawa’s path integral framework is considered and the form of anomaly equation in higher orders is established. An argument for the Adler-Bardeen theorem in this formulation is given.     

Improved method for analyzing quasi-optical launchers

An improved method for analyzing the radiation characteristic of the quasi-optical launcher is presented. The launcher is decomposed into an open-ended waveguide and a helical cut according to the proposed method. The radiation from the open-ended waveguide is obtained by using the Stratton-Chu formulation. The helical cut＇s radiation is calculated based on its current distribution, gained by several iterative computations, which helps to improve the calculation accuracy since the diffraction effect introduced by the helical cut is considered during the calculation. The proposed method is used to study different launches, and the results are compared with the existing results. Good agreement is achieved between the results obtained from our proposed method and the reported results. The present results provide an alternative for analysis and synthesis of the optical-mode converter.