完全非相干白光一维光生伏打暗空间孤子

使用白炽灯作光源在LiNbO₃∶Fe晶体内实验观察到一维白光光生伏打暗空间孤 子. 由奇数 和偶数初始条件分别产生了灰孤子和灰孤子对，它们所感应的波导能导向白光和相干光. 用 相干光清楚地探测到它们内部的多模结构. 该实验证明了白光光生伏打暗空间孤子的存在， 并指出了用完全非相干的白光暗孤子控制和导向相干光的可能性. 关键词： 光生伏打效应 自陷 完全非相干孤子 波导     

Discrete Wavelet Transform: Architectures, Design and Performance Issues

Due to the demand for real time wavelet processors in applications such as video compression [1], Internet communications compression [2], object recognition [3], and numerical analysis, many architectures for the Discrete Wavelet Transform (DWT) systems have been proposed. This paper surveys the different approaches to designing DWT architectures. The types of architectures depend on whether the application is 1-D, 2-D, or 3-D, as well as the style of architecture: systolic, semi-systolic, folded, digit-serial, etc. This paper presents an overview and evaluation of the architectures based on the criteria of latency, control, area, memory, and number of multipliers and adders. This paper will give the reader an indication of the advantages and disadvantages of each design.     

高温氨化合成GaN微晶

分别利用Ga2O3粉末和Ga2O3凝胶作为Ga源,采用NH3为N源,在950℃下,分别将两种反应物与流动的NH3反应20 min合成了GaN微晶。用X射线衍射(XRD)、扫描电子显微镜(SEM)、选择区电子衍射(SAED)对微晶进行结构、形貌的分析,特别是对两种不同途径合成GaN微晶的XRD进行了分析比较。结果表明,当Ga源温度为950℃时两种不同的合成途径均可得到六方纤锌矿结构的GaN单晶颗粒,在氮化温度为850℃和900℃时,利用Ga2O3粉末作为Ga源,仅有少量的Ga2O3转变为GaN;而采用Ga2O3凝胶作为Ga源,在相同的温度下,大部分凝胶经过高温氨化反应均可转化为GaN。     

闪光灯泵浦Nd3+:GGG激光特性研究

用闪光灯泵浦掺钕钆镓石榴石(Nd^3 ：GGG)激光晶体，研究了脉冲宽度0．5ms、1ms、1．5ms和2ms的放电泵浦下激光输出，实验获得了1．92J的最大激光能量．     

美国GPS系统抗干扰技术的现状与发展

对美国GPS系统抗干扰技术的现状与发展趋势进行了探讨和研究．分析了自适应调零、频域、时域滤波的GPS接收天线，接收P(Y)码，接收M码，伪卫星，GPS与INS组合等先进GPS抗干扰技术的发展及特点．介绍了美国最新研制的GPS接收机及抗干扰设备。概述了美国新一代GPS星座发展计划及对提高未来GPS抗干扰性能的影响．综合探讨了GPS抗干扰技术的发展趋势．     

引进监理机制搞好信息系统开发

介绍了在常规模式下开发信息系统项目的不利因素，提出了在信息系统工程项目开发中引入工程监理的信息系统开发模式，对信息系统工程监理的概念、主要工作任务进行了说明，中心论述了在引入了信息系统工程监理机制的开发中的建设方、承建方和监理方的三者关系。     

终端对业务和运营商的影响

详细分析了终端对话音业务和新业务的影响。在分析终端对话音业务的影响时从用户和终端两方面进行了阐述，指明为了进一步提高用户敷和砖络的使用率，运营商在进行话音营销对应逐渐将工作重点适当转向农村市场。也从对个人和行业用户的影响两方面阐明了终端对新业务的影响。     

移动运营商手机游戏业务的战略定位和发展策略探讨

分析了韩国、日本及国内运营商手机游戏业务的发展状况．探讨了手机游戏业务的模式．论述了该业务的战略定位和市场前景。从地区提供给移动通信市场对外部环境、产业链的准备是否充分以及运营商内部的资源和运营状况等三个方面阐明了手机游戏业务发展的关键因素。     

Implementation of RNS-Based Distributed Arithmetic Discrete Wavelet Transform Architectures Using Field-Programmable Logic

Currently there are design barriers inhibiting the implementation of high-precision digital signal processing (DSP) objects with field programmable logic (FPL) devices. This paper explores overcoming these barriers by fusing together the popular distributed arithmetic (DA) method with the residue number system (RNS) for use in FPL-centric designs. The new design paradigm is studied in the context of a high-performance filter bank and a discrete wavelet transform (DWT). The proposed design paradigm is facilitated by a new RNS accumulator structure based on a carry save adder (CSA). The reported methodology also introduces a polyphase filter structure that results in a reduced look-up table (LUT) budget. The 2C-DA and RNS-DA are compared, in the context of a FPL implementation strategy, using a discrete wavelet transform (DWT) filter bank as a common design theme. The results show that the RNS-DA, compared to a traditional 2C-DA design, enjoys a performance advantage that increases with precision (wordlength).