光源形状对干涉场衬比度的影响

推导出面光源照明时杨氏干涉实验干涉场的光强分布公式,分别讨论了矩孔、圆环、圆盘光源照明时杨氏干涉实验干涉场的衬比度及光源的极限宽度。结果表明这些光源照明时干涉场的衬比度各不相同,它们的极限宽度可用同一公式表示。     

欧美国家制成激光加速器

目前，世界上已有3个实验组独立成功地利用激光场的尾波加速单能电子束。当一束强的激光脉冲进入气体或等离子体时。激光的电场可以加速运动的电子，直到相对静止的离子通过库仑场把电子拉回为止。等离子体波沿着激光脉冲的尾场运动。在合适的条件下，电子能够被等离子体波带着走；而以前。被加速的电子的能量是分散的。但是，只要加速过程在合适的时间停止。正在加速的电子可以超过等离子体波，而且所有的电子都达到相同的能量。由法国科研中心（GNRS）的维克多·莫片（Victor Malka）领导的小组和由英国伦敦皇家学院的斯多达·孟格利斯（StuartMangles）领导的小组已精确地调整其激光器和等离子体的参数，分别产生了能量约为170MeV和70MeV的准直电子束。     

关于CAI的思考

 随着计算机的不断普及,计算机辅助教学在教育教学过程中已得到了广泛的应用,这无疑是教育史上的一次新的革命,但在计算机辅助教学过程及CAI软件开发中也暴露出了一些新的值得注意的问题,本文中试将这些问题作一些分析,以供借鉴。在CAI教学过程,下列不良倾向值得注意:彻底否定传统教学形式认为传统的教学方法都是失败的、落后的,都不如计算机辅助教学;而计算机辅助教学则是无所不能,无论什么教学内容、任何课型,只要应用了计算机辅助教学,教学中的任何问题都可迎刃而解,甚至认为一节课不应用计算机辅助教学,就不是一节好课。     

场源基本微元的对称性与场的性质

直接由标量基本微元（点源）和矢量基本微元（电流元等）的对称性和两个基本假设讨论基本微元产生的场矢量的性质。     

Entangling Two Multi-atomic Clusters Through a Cavity Field

Two atomic clusters, which have NA and Ns two-level atoms, respectively, are placed in a cavity but separated spatially. There is no direct interaction between the atoms. All the atoms interact with a single-mode of the cavity field. Quantum entanglement between the two atomic clusters is investigated for various initial states of the two atomic clusters and the field. When the cavity field is initially in a Fock state, we find that the time evolution of entanglement quasi-periodically oscillates regardless of the initial states of atoms. The oscillation period increases as the initial photon number increases. When all the atoms in both of the atomic clusters are initially in the excited state, we show that there is no entanglement between the atomic clusters with NA = NB = 1 regardless the initial state of the cavity field. However, when either NA or NB is larger than one, we find that the entanglement always exists even for a strong thermal field. In cases with different initial states of the atomic clusters, we notice that the entanglement becomes stronger as number of the atoms increases. When all the atoms in both of the clusters in the ground state, we also find that the entanglement can be enhanced even by a thermal field. We also notice that a single qubit can be entangled with multi-atoms which are initially in the ground state by the cavity field initially being in vacuum, thermal, coherent, and squeezed states.     

Nonlocality Property of Three—Mode Correlated Fields

Four three-mode correlated states are generated by two beam splitters.We show that,by means of parity measurement,those light fields exhibit the nonlocality represented by the violation of the Bell inequality.The conditions fo the maximum violation are also studied.     

Robust adaptive matched field processing with sector eigenvector constraints

Standard adaptive beamforming or matched field processing requires accurate replica fields finely gridded over the search parameter space for localization with sidelobe control. This paper presents an Adaptive Matched Field Processing (AMFP) algorithm, which aims at gaining robustness for the environmental mismatch, and simultaneously reducing the real-time computational load. The new method integrates the merits of several AMFP beam-formers with neighboring location constraints, environmental perturbation constraints and sector focusing constraints. The robustness and effectiveness of the suggested algorithm has been illustrated through the numerical simulation and the experimental Mediterranean benchmark shallow-water data.     

The Casimir effect of Reissner-NordstrSm black hole

The stress tensor of a massless scalar field satisfying a mixed boundary condition in a （1 ＋ 1）-dimensional Reissner- Nordstrom black hole background is calculated by using Wald＇s axiom. We find that Dirichlet stress tensor and Neumann stress tensor can be deduced by changing the coefficients of the stress tensor calculated under a mixed boundary condition. The stress tensors satisfying Dirichlet and Neumann boundary conditions are discussed. In addition, we also find that the stress tensor in conformal flat spacetime background differs from that in flat spacetime only by a constant.     

格子点上列完全马氏场的刻划

对于格子点上的马氏规范我们引入“转移律”的概念,并证明了列完全马氏场与转移律之间存在一一对应关系。