高精度三维微结构微细电火花加工系统研究

针对微细电火花加工技术的特点,开发、研制了高精度三维微结构加工的细电火花设备,主要介绍了该装置的结构和数字比例、积分和微分(PID)结合双向静差补偿的控制方法,实现放电间隙与放电状态的自适应调节,并利用该装置进行了平台性能的试验研究,试验结果表明该加工技术响应时间快、平稳、超低速和超高分辨率、加工效率较高,可实现平台在100 mm行程内达到亚微米级精度,最低速度为0.1μm/s,闭环最小步进量为100nm,可满足微细电火花加工的要求。     

对电火花加工规准转换的研究

正一、概述电规准是指在电火花加工中所选用的一组电脉冲参数,包括脉冲电流的峰值、脉冲的周期、脉冲的宽度和脉冲的间隔大小等电参数。在电火花成形加工中,电极会随着加工的进行而产生损耗。电规准选则是否合理,将直接影响到电加工效率和加工质量,因此,电规准应根据工件的加工质量要求、电极和工件的材料性能、机床设备与工艺指标等因素作合理的选择。电火花加工中,在粗加工完成后,再使用其他规准加工,使工件粗糙度逐步降低,逐步达到     

负极性电火花加工时表面做功能量研究及其参数分析

本文基于电子溅射理论和电流电阻热效应,进行了负极性电火花加工时工件表面做功能量的建模与参数分析,并开展了一系列单因素孔加工实验.理论与实验数据分析表明:电阻热效应是材料去除的主要作用机理,且电阻热占总做功能量的集中度随极间电流的提高而增加,随放电斑面积的增大而减小.理论探讨与实验数据分析的一致性表明所建立的能量描述方程有效.     

微细电火花加工装置的设计与应用

设计开发了一台用于微细电火花加工的微细加工装置，它主要由以下几个部分组成：花岗岩基座、精密伺服机构、精密高速旋转主轴、线电极磨削装置、微细电火花加工用的RC脉冲电源、加工状态检测系统和控制系统。在该装置上可以进行微细轴、微细孔和微三维结构的加工。具有4轴3联动功能，控制方便，容易实现数控插补功能。加工实验表明，在该装置上能稳定地加工出最小直径为Ф12μm的微细轴以及Ф25μm的微细孔，其长径比可分别达到25和10以上。并对半导体硅材料进行了加工实验，加工出的硅微梁深宽比达15以上。此外还给出了所加工的微三维结构实例。     

适合于电火花加工的超声马达驱动电源的研制

针对微小型电火花加工系统中超声马达的驱动信号中含有高次谐波的现象,进行了超声电发生器输出端的阻抗匹配。在此基础上,进行了频率自动跟踪设计,使超声马达始终工作在谐振状态或准谐振状态。最后进行了加工实验的验证,其结果表明系统的加工效率得到较大提高,且改善了加工质量。     

微细群孔电解加工试验研究

基于微细电解加工理论,采用微细圆柱群电极进行了微细群孔电解加工工艺试验,研究了加工电压、脉冲宽度、电解液浓度、成分等因素对群孔加工精度的影响。结果表明,减小加工电压和脉冲宽度,采用低浓度钝化性电解液可以显著提高群孔电解加工精度。研究结果对实现微细群孔结构高精度和高效率加工具有指导意义。     

活塞异形销孔加工的研究

依据汽车活塞采用异形销孔的必要性和国内外异形销孔加工的现状，采用压电陶瓷驱动的柔性铰链机构实现镗刀的径向微位移。根据活塞异形销孔几何特征和压电陶瓷驱动器的控制精度高、刚性好和大频响特点，在位置反馈的系统中引入重复控制和反馈通道的开不前馈控制，从而提高了系统的稳定性和跟踪精度。实验表明加工精度可达3μm。     

正极性电火花加工的损耗机理及其参数分析

本文基于场致发射电子对阳极表面材的料溅射能量分析,研究了引起正极性电火花加工时阳极材料的损耗机理,并给出了正极性加工时电极损耗率的理论极大值与极小值方程。设计并进行了不同工艺参数下紫铜电极和A3＃钢电极单孔电火花加工对比实验,实验表明：相同工艺参数下,紫铜电极比A3＃钢电极加工时的极间放电能量大,加工效率对比上前者是后者的极的75倍多,但电极材料的损耗率对比上,前者是后者的近10倍;不同工艺参数下,极间有效放电时间和放电能量越大,加工效率越高,相应的电极的损耗率也增加,但损耗率的增加程度要远小于加工效率的提高程度。     

Excel在线切割加工中的应用

上下异形面零件的加工是线切割数控加工中的难点问题,本文通过实例介绍了如何利用Excel表格对上下异形面零件加工进行辅助编程,缩短编程时间,避免编程过程中出现的人为计算失误,能有效的提高上下异形面零件加工的加工精度和加工效率。     

第五代MOSFET在精加工电源设计中的应用

讨论了第五代ＭＯＳＦＥＴ的性能及其在高频精加工电源设计中的应用。采用高速集成电路门极驱动技术及高速信号检测技术，细化了电火花加工中的单位脉冲能量，提高了脉冲密度增加了有效放电次数，改善了放电条件。在同等加工质量情况下提高了加工效率。     

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