基于PIC单片机的注水变频电机保护测控装置设计

本文介绍了基于PIC单片机的变频注水电机保护测控装置的设计。在分析了注水变频电动机保护需要检测的重要电参数的基础上,重点介绍了装置的软硬件设计。由于采用了PIC单片机芯片进行开发设计,本装置不但可以完成注水变频电机的综合保护、检测与控制功能,而且极大地提高了注水变频电机保护的可靠性和实时性。     

JL系列电动机保护器列为国家火炬计划项目

ＪＬ系列电动机保护器列为国家火炬计划项目一种专门替代热继电器保护电动机的ＪＬ系列产品，不久前列为国家级火炬计划项目（计划编号：９６Ｄ２３１Ｄ７２１０３１５），并获第三届全国电机保护与电工节能技术科技进步奖，通过了国家科委、机械部、电子部、中科院、中国...     

基于神经网络的电机智能检测系统

利用神经网络技术建立电机的检测模型，由计算机构筑电机智能检测系统，与电机控制和执行机构相结合，对电动机进行控制，利用各种新型的传感技术，实现电动机各种参数的数据采集与分析处理，从而对电动机的性能进行判断。     

一种可靠的综合保护电路

电动机断相时,要么,除电机绕组三角接法内部断相外,一般必有一相电流为零;要么,由于电动机负载不变,其余两相电流必然增大3~(1/2)倍,这包括电机绕组三角接法内部断相的电机。我们设计了一种可靠的综合保护电路。电路原理图如下图所示。 (一)工作原理当6V电源建立后,由C_5、R_6组成的微分电路立即产生一脉冲信号,经或门6使触发器10复位,输出为零。这样就保证了电机起动时的信号不致引起电路的误动作。由于电机未起动时与非门1输出高电平,所以触发器10若不先复位,则此高电平也可能使继电器吸合,为此设置了由C_1、R_1、D_1组成的时间电路。当     

基于神经网络的电动机温升智能保护设计

本文调查了国内外电动机各种保护方法和各类保护装置的研究发展状况,结合实际情况,提出了一种通过人工神经网络预测电机绕组温升的方案,由PC机通过RS485总线实时读取下位机采集的电机运行参数,进行温升预测,并将预测结果传输回下位机,从而实现了对电动机长期稳定负载运行的过载保护。     

基于DSP的电动机控制系统的抗干扰技术

数字化控制已成为现代电机控制系统发展的必然趋势，为提高电动机控制系统的准确性和可靠性，完善的电磁兼容设计成为至关重要的因素。文中阐述了基于TMS320F240的DSP电动机控制系统电磁兼容设计方法，包括电路板设计及软件设计。数字化控制有利于提高电动机控制系统的抗干扰能力，增强电动机控制系统的稳定性和可靠性。     

混合式步进电动机两种驱动方案的比较

混合式步进电动机是步进电机发展的主流。其驱动器的研究对提高电机性能十分重要。本文对混合式步进电动机两种驱动方案作了实验比较，分析了各自的优缺点。并给出各种方案下的电机带载突跳频率的实验结果。     

电机软起动的单片机技术固体控制器

本文介绍了一种电机软起动固体控制器的设计原理。该控制器以单片机为控制核心,采用晶闸管调压方式,通过改变晶闸管的触发角来实现对负载电机两端电压的调节,实现电动机的软起动及软停止,同时具有缺相保护、相序检测以及运行状态输出等功能。     

应用于旋转磁场电机新型矢量变换闭环控制系统的磁场定向原理

当旋转磁场电机用作拖动电动机时，转矩的产生和控制就需要得到特殊的考虑。举例来说，就是用定子电压矢量，还是用定子电流矢量来表示产生转矩的变量，取决于给电动机供电的静止变换器是改变电压，还是改变电流。本文描述旋转磁场电机作为感应电动机时的磁场定向原理，这是一种新的闭环控制方法。文中表明，需要如何影响这些变量才能使转矩得到瞬时的、阻尼得很好的调整，而又不受感应电动机固有特性的影响。     

浅谈单相异步电动机的反转

单相异步电动机是由单相交流电源供电的旋转电机，其定子绕组为单相。当接入单相交流电时，它在定转子气隙中会产生一交变脉动磁场，所以单相异步电动机不能自启动。为了使单相异步电动机自启动，就要在启动时产生一个旋转磁场。本文以电容分相式单相异步电动机为例，介绍单相异步电动机的反转。要使单相异步电动机反转，关键在于改变旋转磁场的旋转方向，但又不能像三相异步电动机那样靠掉换两根电源线来实现。本文结合电容分相式单相异步电动机的具体电路形式，讨论了使其反转的三种方法，经实验验证。确实可行。     

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.     

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.     

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.     

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