圆电模到圆波导主模变换器的理论设计

本文介绍了圆电模到圆波导主模变换器的设计理论,简要介绍了解该初值问题所采用的龙格库塔算法;在此基础上,用matlab语言编制了计算程序,计算结果表明,在不同频段该变换器的转换效率可以达到98％以上,利用程序可以计算不同半径、不同频点处的圆电模到圆波导主模的变换器。     

用于毫米波固态源的低通阻抗变换器设计

消除低频不稳是利用雪崩管设计毫米波固态源,特别是大功率源的重要课题.本文设计了一种新型的可调谐式低通阻抗变换器以消除振荡源的低频不稳定性.该变换器不仅能大大地抑制低频不稳,而且由它提供的调谐自由度,加上可移动的短路活塞提供的另一调谐自由度可使振荡源调至最佳状态.本文借助计算机对该变换器进行优化设计,并给出其带通特性的理论曲线.     

压电变换器缩小了背光机构的体积

压电变压器设计的改进终于使得压电变换器能够实际应用于驱动CCFL背光机构。所设计的变换器体积小,重量轻,而且效率高可以用于当今的移动电子产品。 Tamura公司(位于美国加州的Temecula)最近推出了具有专利权的压电变换器产品,它比铁磁变换器的体积更小,效率也更高。据该公司介     

用UC3860组成的1MHz150W准谐振型功率变换器

ＵＣ３８６０是美国Ｕｎｉｔｒｏｄｅ公司推出的准谐振式电源变换器控制集成电路，本文将详细探讨准谐振型半桥式变换器电路的设计方法，文中给出的一些具体计算方式，将同样适用于其它电源电路的设计。     

一种自驱动型LLC半桥谐振变换器的研究

在三谐振LLC变换器基础上,简化控制电路,提出了一种新型的LLC型自驱动半桥谐振变换器拓扑,并分析了该变换器的工作原理。由于它与传统谐振变换器相比,省略了昂贵的半桥驱动芯片和复杂的变频控制策略,实现了全负载范围内零电压开关,提高了变换器的效率、可靠性及功率密度,降低了成本。所以该拓扑十分适合应用于中间母线式变换器中,文中详细讨论了其参数设计。     

DC-DC变换器的大信号建模及鲁棒控制方法

本文从工程实践的要求出发,将建模和控制器的设计紧密结合,提出了一种新型DC-DC变换器大信号建模方法,基于这一模型,将线性时变不确定系统的鲁棒控制方法应用于DC-DC变换器的控制器设计.本文所提出的建模和控制器设计方法适用于全部四种基本PWM型DC-DC变换器.计算机仿真和实验证明,本文设计的控制器对输入电源电压扰动和线性负载电阻扰动具有良好的鲁棒性,且实现方案简单易行.     

20瓦简单开关正向变换器

采用ＬＭ２５７７开关ＩＣ,可开发一种正向变换器拓扑结构的２０瓦（５Ｖ,４Ａ）降压稳压器。这种正向变换器可以容易地提供输入和输出之间的电隔离。设计指标Ｖｉ范围：２０Ｖ～２４ＶＶ：５Ｖ４ＡＶ：２０ｍＶ下面分述这种变换器的变压器设计,输出滤波器设计和缓冲电路设计。基本的正向变换器示于图１。变压器设计１．采用最大开关电压、输入电压和缓冲电压来计算变压器的初级／箝位线组的匝数比：选Ｎｐ／Ｎｃ＝１．２５其中Ｖ电压是由变压器的初级漏电感所产生的电压尖峰的估计值。２．开关的占空度ｔｏｎ／Ｔ由初级线组的伙一秒（Ｖ…     

固定频率PWM微功率DC／DC变换器设计

在电池供电的计算机、消费类产品和工业设备中,DC／DC变换器是重要的部件。变换器有两种类型：线性变换器和开关变换器。开关变换器主要有三种拓扑结构：降压变换器（开关稳压器将一输入电压变换成一较低的稳定输出电压）;升压变换器（开关稳压器将一输入电压变换成一较高的稳定输出电压）;逆向变换器（开关稳压器将一输入电压变换成一较低的稳定反相输出电压）。在此用Motorola的MC33466微功率开关稳压器来设计降压变换器、升压变换器和逆向变换器。MC33466器件具有非常低的静态偏置电流（典型值15pA）,含有高精度电压基准、振荡器…     

PH系列DC／DC变换器模块应用

日本ＮＥＭＩＣ－ＬＡＭＢＤＡ公司生产的ＰＨ系列ＤＣ／ＤＣ变换器模块是一种功率密度非常高且性能较好的直流变换器，上前已广泛应用于通信自动控制和计算机中。本文简要介绍了这种模块的内部结构和引脚功能，能详细地介绍了外国电路的设计方法和实际应用技巧。     

一种新型DC/DC变换器实验系统开发

为强化DC/DC变换技术的实践教学,基于多绕组变压器和反激电路原理,开发一套DC/DC变换器教学系统。设计变换器的拓扑结构,分析工作原理及控制策略,计算变换器系统参数,建立数字仿真模型,设计变换器主电路、输出电压采样电路、开关管驱动电路等来搭建变换器实验平台。实验教学应用表明,该变换器实现宽输入/输出电压范围功能的同时,能够提高学生的电力电子技术综合实践能力。     

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