中国的三种非同步轨道卫星移动通信系统星座方案

本文介绍基于我国的三种非同步轨道卫星移动通信系统星座方案：低、中轨系统各有２４和１８颗星，轨道高度分别为１３２６和８０３５ｋｍ，两系统各以５°和３０°的仰角对我国的覆盖率为９９．７８％和９９．９６％；椭圆轨道系统１２颗星，近、远地点分别为４２７和２９０６ｋｍ，以７°和１５°仰角对我国北纬２０°以上地区覆盖率分别为９７．９０％和８９．６１％，若增加４颗中轨卫星，以１５°仰角对我国的覆盖率为９９．９９％。     

Towards a generalized TLM algorithm for solving arbitraryreciprocal and nonreciprocal planar structures

A generalized transmission line matrix (TLM) algorithm is developed in the frequency domain to tackle arbitrary both reciprocal and nonreciprocal anisotropic waveguiding problems. In particular, the modeling issue for arbitrary planar structures is stressed in this work. A new three-dimensional (3-D) condensed node is used to consider the effect of both electric and magnetic constitutive tensors. Various results indicate how the modal dispersive behavior can be manipulated by changing not only the anisotropic characteristics of the substrate, but also the strip/slot geometry as well as the magnitude and orientation of the applied static magnetic field. The present algorithm is useful for CAD and simulation of a large class of gyrotropic waveguide-based microwave and millimeter-wave circuits     

处理原子-辐射场相互作用系统的变分方法

用Heisenberg-Weyl(简H-W)群直积SU(2)群上的相干态表述了原子-辐射场相互作用系统的非平衡态统计力学.引入一个新定义的含时分布函数,将非平衡态下密度矩阵所满足的von Neumann方程转化成可分离变量的偏微分方程,给出了方程的形式解,算符的平均值表示.本文还就便于作微扰展开的相互作用绘景作了讨论.     

An analytical grain-barrier height model and its characterizationfor intrinsic poly-Si thin-film transistor

An analytical model for the grain-barrier height of the intrinsic poly-Si thin-film transistors (TFTs) is developed, in which the grain-barrier height for the applied gate voltage smaller than the threshold voltage is obtained by solving the charge neutrality equation and the grain-barrier height for the applied gate voltage larger than the threshold voltage is obtained by using the quasi-two-dimensional (2-D) method. Good agreements between experimental and simulation results are obtained for a wide gate voltage range     

羰基镍分析报警仪

羰基镍分析报警仪运用化学发光原理构成，不仅适用于羰基镍生产车间现场的检测和报警，也适于实验室的研究工作。检出限达0.037mg/m^3(0.5ppb），响应时间2min。     

A microprocessor-based toggle-control lighting system

Analysis, design, practical consideration, and implementation of a microprocessor-based toggle-control lighting system are presented. The system is primarily configured with a power factor corrector (PFC), a square-wave voltage generator, a manually controlled toggle switch, and two relays. Toggling the toggle switch can select a different number of lamps in operation, resulting in a mutual dimming feature. A fluorescent lamp lighting system with this specific ballast gains the merits of lower system cost and more flexibilities in lighting fixture design, as compared to conventional systems     

Resolution of Secondary α-Ketoalcohols Catalyzed by Lipase and Inversion of Stereochemistry

Several α-ketoalcohols of synthetic value were resolved using lipase as a catalyst. Lipoprotein lipase (LPL) provided the best rate of hydrolysis and kinetic differentiation. One of these optically pure α-ketoalcohol was converted to (5)-ibuprofen in good optical purity. The stereospecific inversion of (R)-alcohol to (S)-alcohol is described.     

Analysis of dispersion characteristics for a circular dielectric waveguide with periodic metallic strips by using the method of lines

The dispersion characteristics of circular dielectric waveguide with periodic metallic strips are analyzed by the method of lines. The filter property of the metallic strip loaded structure is carefully investigated for both TE and TM modes. The brillioum diagrams for both TE₀₁ and TM₀₁ modes are given. A comparison is made between the results obtained by Galerkin's method and those calculated with the method of lines, and very good agreement has been found; the accuracy of the present method is thus justified. On the basis of the analysis, some useful guidelines for the design of the bandreject filters are suggested.     

激光扫描共焦荧光显微镜的电子控制系统研究

介绍了激光扫描共焦荧光显微镜的电子控制系统，为了提高激光扫描器的定位精度，在系统中提出采用基于闭环象素时钟发生器的检流计振镜所固有的扫描非线性失真补偿方案，减少输出图象的枕形畸变，实现行扫描空间位置的均匀性。在以细分梯形波电流驱动反应式步进电机情况下，根据实测θｉ曲线，用反插法求得与步进电机运行非均匀性相补偿的相电流波，从而获得在小电流情况下高角度均匀的步进电机细分运行特性。