电子产品的瞬变和浪涌防护

电子产品在使用中的电压瞬变和浪涌将导致电子产品的损坏,因此,电压瞬变和浪涌防护问题已经得到越来越多设计得的重视。文章在指出防护的必要性的同时,还介绍了瞬变和浪涌防护器件的分类及特性,并重点介绍了三种电子产品中瞬变和浪涌防护器件的选择和应用方法。     

电厂数字程控交换机防雷措施分析

提出了雷击对电厂数字程控交换机的几种具体破坏形式,阐述了电厂数字程控交换机预防雷击的一些观点和方法经验,通过数字程控交换机安全接地、数字程控交换机防雷击电磁脉冲、数字程控交换机电源浪涌防护、以及数字程控交换机信号防雷保护等措施来满足国家制定的相应安全防雷规范,从而实现电厂数字程控交换机安全可靠防雷,实现电厂数字通讯网的安全可靠平稳运行。     

防浪涌器件的并联保护应用

电气电子设备可能由于雷击、运行操作中的过压,而承受浪涌电压(电流),必须采用浪涌抑制器件构成保护电路加以抑制。浪涌测试模拟了在电源线和长信号线上可能出现的高能量但相对较慢的瞬态过压现象,浪涌抑制器件与被保护电路并联,来观察是否能起到对电路更好的保护作用。     

网通浮地产品共模浪涌防护设计

浮地产品共模防护浪涌设计,在符合相关电磁兼容(EMC)标准要求的前提下,宜尽量减少EMC保护器件的使用,做到成本最优,从而提高产品的性价比。文章从产品的角度出发结合认证和行业的标准要求,给出产品的测试方法,分析了此类产品的共模浪涌防护设计方案及其防护原理。针对各类功能端口共模防护方案浪涌电流泄放路径,提出了相应的防护方案,并证实了电路安全可靠。     

服务器网卡RJ45接口雷击浪涌测试问题分析

服务器是数据中心的核心计算单元,而服务器网卡是服务器进行数据交互的重要组成部件。服务器网卡的性能和稳定性直接关系到服务器数据交互的功能。服务器网卡RJ45接口由于外接一定长度的网线将服务器连接到交换机或路由器网络,很容易遭受到雷击浪涌的考验。服务器网卡RJ45接口防雷击浪涌的设计好坏,直接关系到整个数据中心是否能够顺利运行。雷击浪涌测试是模拟户外雷击放电时,对信息技术类设备所感应出的雷击电压抗扰度能力的一种测试,雷击浪涌测试对于网口网络变压器初次测试的元器件存在较大的风险和考验。由于雷击浪涌测试电压常在千伏级别,很容易造成元器件击穿烧毁的现象。     

电子产品的浪涌(雷击)防护

就浪涌(雷击)对电子产品的危害及相应对策进行了分析,并对各种对策器件的特性进行比较,以方便大家的选用,同时对电子产品几个不同部位的雷击防护设计方法进行了探讨和举例,以供大家在进行产品设计时参考.     

电子产品的(雷击)浪涌防护标准及测试

本文首先就电子产品的雷击浪涌损害机体及防护方式进行了简要的说明.接着通过对几个常用的电子产品浪涌检测标准的讨论就电子产品雷击浪涌防护测试项目选择,测试方法、判断准则等方面进行了重点介绍,以方便大家在电子产品的浪涌防护设计和测试标准有一个全面的把握.     

泰科Raychem电路保护部新增气体放电管产品

泰科电子Raychem电路保护部宣布,公司的电路保护产品系列新增了气体放电管(GDT)。新增的气体放电管主要针对电信设备和浪涌保护模块,以及工业、商业、消费类和汽车电子等领域。Raychem电路保护部的气体放电管可通常用于保护敏感的电信设备,例如电源线、通信线路、信号线和数据传输线,防止一般由雷击和设备开关操作导致的瞬时浪涌电压所造成的损坏。气体放电管作为一个高阻抗器件,可放置在敏感设备的前面并与之平行,同时该器件不会影响信号的正常工作。但是,在雷击等过电压浪涌情况下,气体放电管会切换到低阻抗状态,并将能量从敏感设备中转…     

大功率机载电子设备瞬态电压保护电路设计

介绍了机载配电系统中过压浪涌与欠压浪涌两种瞬态电压干扰的信号特征及防护机理。阐述了目前常见的几种瞬态电压防护方案电路的基本原理,分析了这几种防护方案对大功率设备的限制因数。采用一体化设计思想,提出了大功率设备断电型瞬态电压保护电路,并设计了样机。最后通过试验验证了大功率设备的断电型瞬态电压保护电路可有效抵抗机载航空电源所产生的浪涌电压。     

大型无线电台站的防雷措施

大家知道,雷电会损坏通信设备,甚至会造成建筑物倒塌,人员伤亡。自从２００多年前富兰克林发明避雷针之后,建筑物得到有效的保护。但是,随着现代无线电技术的不断发展,大量精密通信设备的使用,雷击造成设备损坏的事故呈上升趋势。这是由于无线电通信设备大量采用了ＣＭＯＳ集成模块和ＣＰＵ控制单元,由这些微电子器件组成的电路普遍对电网电压要求很高,耐过压、耐过流能力下降,对雷电浪涌的承受能力下降。每年各种通信系统或网络因浪涌电压而受破坏的事例屡见不鲜。 现代防雷的技术原则强调全方位防护,综合治理,层层防护,把防…     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks