核物质热力学性质的同位旋和动量相关性

利用3个具有不同的同位旋和动量相关性的热力学模型研究了非对称核物质的热力学性质, 它们是重离子碰撞中同位旋弥散数据约束下的、 同位旋和动量相关的MDI模型, 完全动量无关的MID模型, 以及同位旋标量动量相关的extended MDYI(eMDYI)模型。 主要研究了同位旋非对称热核物质的对称能和系统力、 化学不稳定性以及液气相变的温度效应。 MDI模型对称能的温度效应来源于动能和势能两部分贡献, 而MID和eMDYI模型只有势能部分对对称能的温度效应有贡献。 研究结果还表明, 力学不稳定性区域、 化学不稳定性区域和液气共存区都依赖于模型的同位旋和动量相关性, 以及对称能的密度依赖关系。In this article, three models with different isospin and momentum dependence are used to study the thermodynamical properties of asymmetric nuclear matter. They are isospin and momentum dependent MDI interaction constrained by the isospin diffusion data of heavy ion collision, the momentum independent MID interaction and the isoscalar momentum dependent eMDYI interaction. Temperature effects of symmetry energy, mechanical and chemical instability and liquid gas phase transition are analyzed. It is found that for MDI model the temperature effects of the symmetry energy attribute from both the kinetic and potential energy, while only potential part contributes to the decreasing of the symmetry energy for MID and eMDYI models. We also find that the mechanical instability, chemical instability and liquid gas phase transition are all sensitive to the isospin and momentum dependence and the density dependence of the symmetry energy.     

利用调整技术补偿离轴抛物面反射镜面形误差

为了提高光学系统的成像质量,对离轴抛物面反射镜的面形准确度要求越来越高,这大大增加了反射镜的加工难度.本文基于波像差理论,分析了在离轴抛物面反射镜中调整量引入的波像差,提出通过适当调整离轴抛物面反射镜的位置补偿反射镜的面形误差,可以降低离轴反射镜的加工难度、缩短其加工周期、减少加工成本.并借助于ZEMAX软件对一块面形准确度低于λ/40 RMS (λ=632.8 nm)离轴抛物面反射镜进行仿真实验,根据理论计算的调整量调整反射镜的位置,得到了补偿后的离轴抛物面反射镜的面形误差小于λ/60 RMS,仿真结果表明在离轴抛物面反射镜中引入适当的调整量可以有效地补偿反射镜的面形误差.     

Study of a millimeter-wave squint indirect holographic algorithm suitable for imaging with large field-of-view

In this paper a millimeter-wave （MMW） squint indirect holographic method is presented, which is suitable for imaging with a large field-of-view. The proposed system employs the squint operation mode to remove the background and twin- image interferences, which achieves a similar effect to off-axis holography but leaves out the large-aperture quasi-optical component. The translational scanning manner enables a large field of view and ensures the image uniformity, which is difficult to realize in off-axis holography. In addition, a corresponding imaging algorithm for the presented scheme is developed to reconstruct the image from the recorded hologram. Some imaging results on typical objects, obtained with electromagnetic simulation, demonstrate good performance of the imaging scheme and validate the effectiveness of the image reconstruction algorithm.     

丝状相液晶由表面相互作用产生的相变

导出双轴丝状相液晶在指向矢与易取向轴重合时的表面相互作用能.应用Ritz方法,对半无 界液晶体得出沿表面法向的双轴相(B_c)至沿表面某一轴的双轴相(B_a)的相变.随着表面锚泊强度双轴性部分的增大,B_a的产生机制逐渐由降低温度 转为表面锚泊,因此B_a相可出现在较高温度和较大温度范围内.在表面锚泊强度 单轴性部分α值的一定范围内,增大α值可使B_a在较高温度产生,但α值的进 一步增大则使液晶又从B_α返回B_c相. 关键词： 液晶 相变 表面能     

49≤Z≤53类钴离子3d^9-3p^53d^10，3d^9-3d^84p跃迁谱线和振子强度的计算

用等电子序列高离化态离子能级△E随Zc的一般拟合公式,系统计算了中Z段49≤Z≤53类钴离子的能级,并给出了3d^9-3p^53d^10,3d^9-3d^84p跃迁的波长和振子强度。     

Dislocation Dissociation Strongly Influences on Frank-Read Source Nucleation and Microplasticy of Materials with Low Stacking Fault Energy

The influence of dislocation dissociation on the evolution of Frank-Read （F-R） sources is studied using a three- dimensional discrete dislocation dynamics simulation （3D-DDD）. The classical Orowan nucleation stress and recently proposed Benzerga nucleation time models for F-R sources are improved. This work shows that it is necessary to introduce the dislocation dissociation scheme into 3D-DDD simulation, especially for simulations on micro-plasticity of small sized materials with low stacking fault energy.     

相对论能量正比于动质量的一般性证明

依据相对性原理,仅仅要求粒子的动量和能量在不同的惯性系中具有相同的函数形式,即可一般性地证明相对论能量必须正比于动质量.这一特性为相对论本身的自洽要求,而与线性时空变换的具体形式无关,也与光速不变的假设无关.依据这一特性,同时也一般性证明了质量守恒定律等价于能量守恒定律.     

基于单幅数字散斑投影及图像相关的离面振动测量

采用单幅数字散斑图投影及高速数字图像采集技术,研究了动态离面位移的测量。采用商用液晶投影仪将计算机产生的模拟散斑图投影到待测动态变形物体表面,由高速数字图像采集设备摄取并保存变形散斑图,采用时间序列数字图像相关软件计算出物体表面各点随时间变化的离面位移。这种方法用于振动分析时不仅可以获得振型分布,而且还可以获得各点的振幅值。与现有的激光频闪照相测振及激光多普勒测振等方法相比,具有光学系统简单,可全场定量测量。悬臂梁振动实验结果证实了该方法的有效性。     

Covariant Perturbation Theory of Non—Abelian Kinetic Theory

A “double perturbation” theory is presented in the framework of the kinetic theory of quark-gluon plasma.A solvable set of equations from the double perturbation are derived and proven to be gauge invariant.The Landau damping rate for the plasmon at zero momentum is shown to be a convergent series in correlators.