高速钢激光相变强化层的耐磨性及刀具的切削性能

研究了Ｗ１８Ｃｒ４Ｖ高速钢激光相变强化层的组织和耐磨性能，并对高速钢刀具的切削性能及失效形式进行了分析讨论．结果表明：高速钢经激光相变强化后组织和性能得到了很大的改善，硬度达１００３Ｈｖ０．１以上，且韧性有显著提高，耐磨性提高了２～８倍．刀具激光相变强化后．寿命提高了３～５倍，是以磨损形式失效的。     

高速钢激光重熔后的组织与性能

研究了W18Cr4V高速钢激光重熔后的组织与性能。结果表明，常规淬回火组织经激光重熔后其硬度、韧性都有提高，熔化层的残余应力为技应力；经640℃回火后；由于残余应力的消除及重熔组织中马氏体的二次硬化和残余奥氏体的二次淬火效应其耐磨性能有了进一步地提高。     

45钢激光相变强化梯度组织的研究 (原始组织的影响)

通过试验 ,分析研究了 4 5钢激光相变强化梯度分布的显微组织特征以及原始组织对 4 5钢激光相变强化梯度组织及其显微硬度的影响。通过对不同原始组织激光相变强化效果的对比分析 ,指出原始组织越细小弥散 ,成分越均匀 ,缺陷密度越高 ,材料的临界硬化温度越低 ,越有利于激光相变强化。在相同的激光处理工艺参数下 ,原始组织为淬火高温回火态时 ,激光相变强化的效果最显著 ,正火态次之。淬火回火态的激光相变强化比退火态具有更大的硬化层深度及更高的显微硬度     

激光冲击诱发相变的实验研究

本对激光冲击是否可以诱发相变进行了试验研究。用功率密度为１．０６×１０＾８Ｗ／ｃｍ＾２的激光器冲击Ｔ８钢表面。实验结果表明激光冲击处理使Ｔ８钢的表面显微硬度有所提高并可以发生马氏体相变。冲击处理后材料表面硬度提高了两倍，认为相变是Ｔ８钢表面硬度提高的原因之一。     

激光硬化和渗氮复合处理W9Mo3Cr4V高速钢组织与性能

采用激光硬化与渗氮复合表面改性技术,对W9Mo3Cr4V高速钢表面进行了强化处理。利用X射线衍射仪、扫描电子显微镜、电子探针、显微硬度计和摩擦磨损试验机,分别对复合处理试样的相组成、微观组织、成分、显微硬度和耐磨性进行了分析。研究结果表明,复合处理表面改性层主要是回火马氏体、残余奥氏体、Fe3N、Cr7C3、M2C型碳化物所构成。由于激光硬化的晶粒细化作用,以及大量位错、孪晶、空位等微观缺陷的产生,致使氮化层的深度得到明显提高。与单一的激光硬化和渗氮工艺相比,复合处理工艺有效地提高了高速钢的硬度和耐磨性能。     

轴端沟槽底部激光强化工艺参数优化研究

分析了选用不同激光能量密度对HT300进行表面强化处理时，材料表面呈现的四种状况；未相变硬化、相变硬化、表面微熔与表面熔凝的金相组织。根据工艺要求，选取相变硬化方法对轴端沟槽底表面进行处理。分析了工件激光处理方法并通过试验研究，寻找轴端沟槽底部激光强化工艺参数；激光功率（P）、光斑直径（D）及扫描速度（V）的优化组合。硬度测试及耐磨性能试验表明：激光相变处理和激光熔凝处理后轴端沟槽底部表面较表面感应淬火硬度分别提高7%和34%，绝对磨损体积分别下降了13%和25%。实践证实，对轴端沟槽底部激光相变硬化处理方法较其他表面处理方法工艺简单，加工工件符合技术要求，试验结果对零件表面处理提供了可靠依据。     

激光硬化基体对镀铬层组织和结合的影响

采用激光相变硬化的方法在电镀前对基体表层预先进行处理,以改善镀层与基体的结合强度,提高其承载能力。借助扫描电镜(SEM)分析镀铬层的组织和界面,对镀层、相变硬化区和基体的硬度变化进行分析,对镀层抗高温烧蚀能力进行测试。结果表明,基体经激光相变硬化处理后,既可以促进镀层外延生长,又可以在镀层和基体之间实现硬度的梯度过渡,从而可以改善结合,缓解应力,提高承载能力,镀层的抗剥落能力和使用寿命得到显著提高。激光相变硬化得到细小的淬火马氏体,位错密度显著增加,表面活性增强,是促进镀层外延生长的主要原因。     

低碳钢表面激光相变硬化研究

为了研究不同激光功率及不同的冷却条件下,激光相变硬化处理对低碳钢表面性能和组织的影响,采用激光表面相变硬化方法,在低碳钢表面获得了比原先母材硬度高100HV～150HV的硬化层,采用金相显微镜分析了激光处理区的组织,且用显微硬度计测量了单道扫描时的纵向和横向的硬度分布.研究发现,激光作用区主要是低碳板条马氏体与未转变的索氏体甚至屈氏体、回火索氏体组织.搭接区组织均为细小的马氏体及中间分布着索氏体组织;由于10CrNiMo钢含碳量较低和碳扩散系数不同的原因,其最高硬度层并未在表面形成,而是形成在次表层.在软化区,前一道扫描形成的马氏体受到回火作用,原先固溶在马氏体中的碳析出,形成了回火索氏体,降低了硬度.结果表明,激光相变硬化工艺可以将10CrNiMo钢的表面硬度提高100HV～150HV左右,且表面保持很好的韧性,若想进一步提高其表面硬度,还需采取熔覆等其它工艺.     

脉冲Nd:YAG激光熔凝处理5Cr4Mo3SiMnVAl模具钢的组织特征

对回火态5Cr4Mo3SiMnVAl(012Al)冷作模具钢脉冲NdYAG激光熔凝处理后的熔凝区、相变硬化区及回火区的组织进行了研究.激光熔凝处理后得到六层不同的组织.对这六层组织进行了SEM观察.在用一维解析模型计算出脉冲NdYAG激光熔凝处理的温度场、温度梯度场和冷却速率场的基础上,结合快速凝固理论和固态相变理论对前五层组织的形成原因进行了讨论.     

T10钢激光相变硬化的组织与性能研究

采用激光相变硬化工艺对T10钢表面进行了改性处理,并对改性后的组织与性能进行了研究,结果表明:硬化区组织为针状马氏体+少量残余奥氏体,热影响区组织为少量针状马氏体+网状渗碳体.基材组织为回火马氏体.淬硬层表面的洛氏硬度最高值为940Hv0.1,淬硬层内的显微硬度分布均匀,从硬化区→热影响区→过渡区→基材显微硬度呈梯度变化.激光相变硬化后淬硬层耐磨性分析,要比常规淬火后耐磨性提高10%左右.     

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.     

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.     

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