用激光技术识别材料的独特密码

造伪问题日趋严重,许多安防部门正在积极寻找先进工具,以帮助防伪人员识别欺诈行为,如护照、身份证、信用卡和钞票等的真伪识别.现行的防伪方法都有缺陷,均要求在被识别物体上加水印、全息图及射频ID芯片.     

DVB-H中高效PRBS的实现研究

本文介绍一种不同于传统的PRBS处理方式,该方法基于Verilog HDL语言,用于改进传统的PRBS串行处理方式,以实现DVB-H/DVB-T传输系统中高效的PRBS的并行处理,提高系统性能.     

迷向映照和伪Veronese流形

本文讨论了伪Riemann流形之间的迷向映照。作为从伪Riemann球面到伪Riemann球面的极值浸入的新例子,本文从伪Riemann球面之间的迷向调和映照中确定了所有的伪Veronese流形。最后,利用某些几何量来刻划双曲类空的Veronese流形。     

人造参考星系统设计

简述了人造参考星系统，并用该系统作为大型望远镜主动光学和自适应光学的Ｓｈａｃｋ－Ｈａｒｔｍａｎ波面探测系统的光源。     

伪轨跟踪性质与不变概率测度

本文利用遍历理论讨论有伪轨跟踪性质的紧致度量空间上的连续满射所具有的动力性质和混沌性态．     

UHF频段衰落信道的仿真

在通信卫星发射前，为了验证地面设备的工作特性，本文设计了一个测试平台，模拟ＵＨＦ频段信道衰落特性，并给出了衰落与多普勒环境下设备性能测试情况。     

THE LARGE TIME BEHAVIOR OF SPECTRAL APPROXIMATION FOR A CLASS OF PSEUDOPARABOLIC VISCOUS DIFFUSION EQUATION

The asymptotic behavior of the solutions to a class of pseudoparabolic viscous diffusion equation with periodic initial condition is studied by using the spectral method. The semidiscrete Fourier approximate solution of the problem is constructed and the error estiation between spectral approximate solution and exact solution on large time is also obtained. The existence of the approximate attractor AN and the upper semicontinuity d(AN,A)→0 are proved.     

利用特征为2域上伪辛几何中1维非迷向子空间构作PBIB设计

关于结合方案和PBIB设计的定义及所用的有关符号见文献[1].设F_q为特征为2的有限域,q=2~r.熟知F_q上的对称矩阵合同于以下三种形式的矩阵(见[1]p.24).     

TD-SCDMA多媒体手机二季度面世

近日，天科技成功实现了全球首个基于TD-SCDMA商用终端参考设计平台的128k包交换数据传输，为TD-SCDMA手机厂商丌发丰富的3G多媒体应用提供了有力的支持，并为突出体现TD-SCDMA这一优秀的3G标准在高速包交换数据传输方面的特殊优势奠定了基础。采用天科技解决方案的商用多媒体手机将于今年二季度面世。     

Pseudo-Spin-Valve Trilayer Using Amorphous CoNbZr Layer： Giant Magnetoresistance, Domain Structures and Potentials for Spin-Electronic Devices

We propose a pseudo-spin-valve (PSV) trilayer using amorphous CoNbZr Mloy for soft magnetic layers. The giant magnetoresistance (GMR), domain structures and their variation upon thermal annealing are investigated. The GMR effect is not only stable up to 300℃ but also enhanced due to the improvement of the interfaces between Cu and magnetic layers. With high annealing temperature, the magnetoresistance (MR) ratio decreases rapidly as a result of serious layer interdiffusion. Dense stripe domains, which disappear after annealing at 300℃ for 1h, are observed in the sandwiched films. It is found that after patterning to elliptic stripe with aspect ratio of 6:1, the trilayers have a single domain and their MR ratio increases. The dynamic MR behaviour under an ac magnetic field indicates that the patterned stripes have good linear MR responses. Therefore, it is believed that the CoNbZr/Cu/Co PSV trilayers have strong potentials for spin-electronic devices including magnetic random access memory.