Ad-hoc网络上的动态路由协议研究及实现

概要介绍了Ad-hoc网络的概念。通过分析其网络特点,描述了该种网络对动态路由协议的要求。简要介绍了当前流行的几种Ad-hoc动态路由协议及特点。详细描述了OLSR路由协议的术语和主要思想。最后结合工程实践,介绍了实现该协议过程中的关键问题,并在模拟网络环境下验证了该协议的正确性。     

平板式超声振子振动模态与谐响应有限元分析

利用Ansys建立了平板式超声振子的模型,对其进行了模态分析,并通过实验进行了验证。同时对超声振子进行了谐响应分析,得出了超声振子的理论振幅值。利用Ansys动画模拟的功能对超声振子进行了结构优化设计,设计出了合理的超声振子结构。有限元分析结果为超声振子的优化设计提供了理论依据。     

一种采用电容共用技术的DC-DC开关电源软启动电路

开关电源DC-DC转换器已经在各种电子设备中取得了广泛的应用。软启动电路保证了DC-DC转换器的正常启动,防止了器件的损坏。从理论上分析了软启动电路原理,设计了一种新型的开关电源软启动电路,该电路引入了电容共用方法,通过与频率补偿电容共用节省了软启动电容,降低了应用成本。并给出了具体电路实现,Spectre仿真结果验证了这种电路的可行性。     

覆铜箔板又要涨价？!

3月14日CPCA召开了四届七次常务理事会和四届四次理事会。会议由理事长莫少山主持,闫海忠、刘述峰、陈文录、杨雪林、王树柏、王龙基副理事长出席了会议。曲连虎副理事长因病请假。会议通过了2004年工作汇报及2005年工作设想,通过了协会经费的预、结算。通过增加常务理事3名,理事5名。通过了关建华为中日电子电路友好促进会副会长的提名。通过了CPCA参加ECWC11工作组名单。通过了CPCA国家二级分会会长及部分人员的组成名单等。常务理事们畅谈了中国及世界PCB的现状及发展趋势,并对协会的工作进行了畅所欲言的探讨。整个会议在团结、…     

基于单片机的智能型多波段LED诱杀虫系统设计

为开发低成本的无公害灭虫技术,设计了一种基于单片机的智能型多波段LED诱杀虫系统。文中给出了单片机主控电路原理图的引脚连接。设计了系统软件,给出了主要程序流程图,并对单片机进行了软硬件测试,结果表明系统实现了相应功能。     

基于FPGA动态信号产生器设计

主要介绍了研制动态5 MHz信号产生器的背景及利用FPGA实现动态5 MHz信号产生器的原理和方法。介绍了所应用的DDS基本原理,说明了信号发生器的内部结构和软件流程。给出了信号产生器关键参数的计算方法。简要介绍了器件选择依据,最后给出了仿真波形。通过试验,验证设计达到了预期目的,充分显示了DDS与FPGA相结合的好处。     

华为的世代交替

近日，华为发布了2010年年报。这份年报最大的亮点就是首次公布了华为的董事会成员以及他们的简历。从公布名单不难看出，一场世代交替正在华为静悄悄地进行中。一方面，它考虑了过去的延续性，“新”董事会排名前6的均为上届董事；另一方面，它也大胆地引入了新鲜血液，一些新人进入了最高决策层。有了这样的延续性和新鲜血液，让我们对华为未来的发展又多了一份信心。     

四大激光技术,武装半导体工业

激光技术自诞生以来,受到了广泛的关注,并逐步拓展了其应用领域。激光技术给制造业带来了根本性变化：在航天工业中,铝合金用激光焊接的成功应用是飞机制造业的一次技术大革命。在汽车工业中,激光加工技术优化了汽车结构,提高了汽车性能,降低了耗油量。激光精加工和微加工不但促进了微电子工业的发展,也为半导体制造行业提供了有利条件。     

复杂铝合金零件镀银工艺改进

介绍了复杂铝合金零件镀银工艺,分析了影响铝合金电镀层质量的因素,通过试验改进了铝合金电镀工艺,在常规二次浸锌工艺中增加了电镀锌,采用浸锌电镀锌联合处理法提高了复杂铝合金零件镀银的结合力。给出了工艺流程及各工序溶液配方和相关参数,并提出了相应的操作要点。介绍了生产过程中易出现的问题及解决办法。利用划格法和热震法检验了镀层的结合强度。测试结果表明:采用新工艺加工的零件达到了结合力的要求。     

基于ZEMAX的红外光学系统设计与优化

阐述了该光学系统研究的意义,确定了基本设计原则。然后进行了平行光管和望远镜的高斯光学结构模型及设计,建立了具体的数学模型并进行求解。最后根据目标耦合光路结构,利用ZEMAX软件对该光学系统进行了优化设计,对优化结果进行了像质评价,得出了结论。该系统解决了红外光学精确制导系统动态跟踪特性的内场测试的一系列问题,促进了红外黑体跟踪目标地面等效测试的发展,对提升仿真试验技术能力提供了重要的硬件支撑。     

TFT LCD常见点缺陷的检测与修复

TFT—LCD在制程中会产生亮点、暗点、闪点、碎亮点等常见点缺陷。说明了检测点缺陷的装置、方法和过程。采用ITO隔离、激光炸射等方法对点缺陷进行修复或者淡化,其中ITO隔离法修复或淡化效果显著。修复成功率从45％提升到80％。     

碲镉汞p-on-n双层异质结材料表面缺陷研究

对碲镉汞p-on-n双层异质结材料的表面缺陷进行了研究。材料表面缺陷会对后续器件的性能产生影响。利用光学显微镜观察外延完的材料表面,发现表面不规则块状缺陷和表面孔洞缺陷较为常见。使用共聚焦显微镜、扫描电子显微镜、能谱分析等测试手段分析发现,缺陷的形成原因是p型层生长过程中镉耗尽以及n型层生长过程中产生缺陷的延伸。     

CZ硅单晶中原生缺陷的特性

描术了ＣＺ硅单晶中原生缺陷的分类,形成机理及它们对相关器件性能的影响,并就其控制和消除的方法进行了讨论。     

HgCdTe薄膜材料缺陷的研究现状

HgCdTe外延薄膜材料中的缺陷是制约高性能红外焦平面器件发展的主要因素。对缺陷的研究与评价是材料生长以至器件制备过程中不可或缺的重要一环．本文详细介绍了HgCdTe外延材料中几种主要缺陷的研究进展．     

Defect analysis and yield degradation of integrated circuits

Various attempts have been made to analyze the yield of integrated circuits in the presence of point defects. This paper analyzes the yield considering both radial and angular variation in the defect density. The effect of statistical variations in the average defect density from slice to slice is also included. Different types of defects which affect the yield are reviewed. The degradation in yield due to point defects, line defects, area defects, and defect clusters is considered in detail. A method of optimum chip placement is described, and the results of computer calculations showing yield as a function of chip size are given assuming different defect density distributions. The results are primarily applicable to large integrated circuit chips.     

Silicon power device material problems

The limitations imposed on the performance of large-area p-n junction devices by the size and quality of the silicon material are reviewed. It is shown that material quality problems--such as nouniform resistivity, foreign particulate matter, microdefects, dissolved oxygen, and various crystallographic defects--represent real limitations on device performance and yields; however, the effects of process-induced defects--such as diffusion- or stress-induced dislocations, diffusant precipitation, heavy metal precipitation, and interface degradation--often obscure, or even overwhelm, the effects of the grown-in defects. The importance of the interaction of process-induced defects with grown-in defects, and particularly the interaction of heavy metals with defects, foreign particulate matter and dissolved oxygen, has been emphasized by the results of recent investigations. The need for defect-free processing techniques in obtaining information on the effects of grown-in defects is discussed. Representative studies of the effects of defects on device performance are listed. New techniques for studying defects are reviewed with reference to results of interest to silicon device technology. Some growth techniques which may be helpful in eliminating certain material quality problems are discussed briefly.     

浮胶引起的缺陷对CCD成像的影响分析

针对大面阵CCD成像黑缺陷多的特点,从机理和制作工艺上进行了分析研究。结果表明,CCD成像黑缺陷主要由光刻工艺缺陷引起。光刻LOCOS、地和沟阻工艺中产生的浮胶是CCD成像黑缺陷的主要来源。在制作多晶硅栅过程中,光刻浮胶可产生成像黑缺陷或导致信号电荷转移问题。最后,提出了减少光刻工艺产生浮胶的方法。     

Effect of conjugation with biomolecules on photoluminescence and structural characteristics of CdSe/ZnS quantum dots

The photoluminescence and photoluminescence excitation spectra, the X-ray diffraction patterns, and the effect of conjugation with biomolecules upon these characteristics are studied for silanized CdSe/ZnS quantum dots. Along with the band of annihilating excitons in the quantum dots, the luminescence spectra exhibit emission associated with defects. It is established that the emission spectrum of defects involves at least two components. It is shown that the defects are located mainly at the small-sized quantum dots; the defects responsible for the long-wavelength component are located mainly at the quantum dots larger in size than the quantum dots, at which the defects responsible for the short-wavelength component are located. It is found that conjugation with biomolecules induces not only the blue shift of the excitonic band, but transformation of the emission spectra of defects and an increase in the contribution of defects to the luminescence spectrum as well. The changes observed in the emission spectrum of defects are attributed to the formation of certain emission centers. It is shown that, when conjugated with biomolecules, the quantum dots experience increasing compression strains. This effect is responsible for the blue shift of the luminescence band of the quantum dots.     

大直径直拉硅单晶中的空洞型原生缺陷

空洞型 ( Void)原生缺陷在大直径直拉硅单晶中的重要性日渐突出。本文在论述大直径硅单晶中 Void缺陷基本性质的同时 ,详细综述了这类缺陷的控制方法以及它与轻元素 (氧、氮、碳、氢 )杂质的相互作用 ,并简要讨论了关于 Void缺陷的研究方法和今后的研究方向。     

Improving Automatic Detection of Defects in Castings by Applying Wavelet Technique

X-ray-based inspection systems are a well-accepted technique for identification and evaluation of internal defects in castings, such as cracks, porosities, and foreign inclusions. In this paper, some images showing typical internal defects in the castings derived from an X-ray inspection system are processed by some traditional methods and wavelet technique in order to facilitate automatic detection of these internal defects. An X-ray inspection system used to detect the internal defects of castings and the typical internal casting defects is first addressed. Second, the second-order derivative and morphology operations, the row-by-row adaptive thresholding, and the two-dimensional (2-D) wavelet transform methods are described as potentially useful processing techniques. The first method can effectively detect air-holes and foreign-inclusion defects, and the second one can be suitable for detecting shrinkage cavities. Wavelet techniques, however, can effectively detect the three typical defects with a selected wavelet base and multiresolution levels. Results indicate that 2-D wavelet transform is a powerful method to analyze images derived from X-ray inspection for automatically detecting typical internal defects in the casting