金属箔板激光动态微拉深成形技术

设计了金属箔板激光动态微拉深实验系统,介绍了该技术的成形机理,结合实验研究了金属箔板激光动态微拉深成形的成形性能.研究结果表明,金属箔板激光动态微拉深成形技术的加工柔性、可控性更好,成形精度更高、成形质量更好,有效地抑制起皱等缺陷的产生.     

Ti-6Al-4V合金的激光净成形制造及其显微组织

对Ti-6Al-4V合金的激光净成形制造进行了研究。实验过程在大气开放环境下进行，仅通过喷嘴吹氩气保护。结果表明，功率质量比对钛合金激光净成形件表面质量以及微观结构有着重要的影响。当功率质量比足够高时可以得到表面光洁度较好的成形件，微观分析显示，激光净成形钛合金的显微组织由细小的针状马氏体α和原始β组成，各层之间为致密的冶金结合。在功率质量比较高的情况下，可以得到柱状晶，反之则生成等轴晶。通过优化工艺参数得到表面质量较好的成形件，而且所制得的样品引入氮氧杂质元素含量较低，可见利用激光净成形技术可以在大气环境下制造出质量满意的钛合金零件。     

激光立体成形Ti-Al-V系的合金力学性能

研究了以元素粉末为送进原料时,激光立体成形(LSF)Ti-Al-V系合金的力学性能。结合激光立体成形Ti-xAl-yV(x≤10,y≤25)合金的硬度测试分析和人工神经网络模型优化,获得激光立体成形Ti-xAl-yV合金成分-硬度的关系。选择典型成分合金进行室温拉伸性能测试,在此基础上获得激光立体成形钛合金抗拉强度与显微硬度的比例因子K值为2.86～3.00,可实现对激光立体成形Ti-xAl-yV(x≤10,y≤25)合金的抗拉强度预测。另外,室温拉伸性能测试结果表明,激光立体成形Ti-4Al-3V、Ti-5Al-3V、Ti-4Al-4V、Ti-5Al-4V以及Ti-3Al-6V沉积态的综合室温拉伸性能均达到Ti-6Al-4V合金的锻件标准。     

TC4激光立体成形显微组织对超声参量的影响

以TC4钛合金激光立体成形件及锻件为研究对象,采用不同热处理制度对TC4钛合金激光立体成形件进行处理得到不同的热处理组织,并采用超声波无损检测方式获得超声波纵波声速和衰减系数,明晰超声参量和显微组织的相互作用机理。结果表明,不同的显微组织具有不同的超声波纵波声速和衰减系数;相比超声波纵波声速而言,衰减系数对TC4钛合金激光立体成形显微组织的变化更为灵敏。     

扭曲薄壁件光内送粉激光熔覆成形温度场研究

根据光内同轴送粉激光快速成形工艺, 建立了扭曲薄壁件激光熔覆成形温度场瞬态有限元数值模型, 模拟了扭曲薄壁件激光快速成形过程的温度场演变过程, 分析了扭曲薄壁件熔覆成形过程中定点温度的热循环, 通过仿真实时控制模型中输入激光功率的大小, 模拟得到了保持熔池温度稳定时激光功率的变化值; 通过层高控制调节激光器功率, 控制熔池的温度稳定, 成功熔覆成形了扭曲薄壁件。性能分析表明: 成形件表面光滑, 没有粘粉, 尺寸与设计数值基本相同, 组织细小致密, 与基体形成冶金结合, 且成形件硬度较高。     

激光立体成形工艺在高性能金属材料加工中的应用研究

研究基于经验工艺参数得到的激光立体成形TC21钛合金沉积态试样中原始β晶粒形貌及其织构特征,分析了激光立体成形工艺在高性能金属材料加工中的应用.结果表明:激光立体成形TC21钛合金宏观组织属于典型外延生长柱状β晶粒,纤维织构特征比较明显;在沿沉积高度方向上,α相尺寸、形貌、体积分数等有显著不均匀性存在,表明TC21钛合...     

激光成形技术的特点及其应用

介绍激光成形的技术的原理、特点,成形机理以及与成形质量有关的工艺参数。并就目前激光成形技术的研究现状和发展趋势做了介绍。     

基于人工神经网络的激光立体成形件成形表面质量预测

通过建立单道折线扫描数学模型,推导出了折线扫描拐角处重叠区域数学描述,从理论上对激光立体成形(LSF)表面质量的影响因素进行了分析,并得出影响折线扫描路径试样表面质量的主要因素是折线角度和扫描速度的结论。建立了适用于激光立体成形件表面质量预测的人工神经网络(ANN)模型,以激光立体成形过程中扫描速度和折线的角度为模型输入,输出成形件表面质量评估参数。经过实验数据训练后的神经网络模型可以实现对不同扫描速度及不同扫描角度成形件表面质量的预测,网络预测值和试验测得值之间的均方差(MSE)小于0.01。     

TC4合金激光立体成形孔洞类缺陷的超声检测

以TC4钛合金激光立体成形件为研究对象,探讨其内部、表面及近表面孔洞类缺陷与超声波的相互作用关系。研究结果表明,在相同检测条件下,对于TC4钛合金激光立体成形件中同深度不同孔径的长横孔缺陷,超声反射波幅值随长横孔直径的增加而增加;对于成形件中同孔径不同深度的长横孔缺陷,超声反射波幅值随长横孔所在深度增加而减小;利用5PФ8纵波直探头,能发现激光立体成形TC4钛合金中0.6 mm大小的孔洞类缺陷;超声表面波沿深度方向发现TC4钛合金激光立体成形件中槽型和孔型缺陷的能力均小于4 mm,且孔型缺陷比槽型缺陷更难发现。     

钨基合金激光立体成形的组织及性能研究

为了制备高性能、大尺寸钨合金零件,利用激光立体成形技术进行了前期探究实验,在大气环境下制备多种配比的W-Ni-Fe高比重合金力学拉伸试验件,通过测试抗拉强度、硬度,结合组织结构和成分配比的探究分析,发现其成形性及力学性能与传统的粉末冶金烧结工艺之间还存在着一定的差距。抗拉强度在W原子数分数为0.6时达到最大值717.5MPa,之后随着W原子数分数的增大反而明显减小,当W原子数分数在0.8以上时,强度已低于400MPa。样品存在孔洞和氧化现象,大量W未溶化,Ni和Fe元素越多,微观组织均匀性越好、成分偏析越小。结果表明,利用激光立体成形技术可对钨基合金堆积成形,但是实验工艺参量和实验环境仍需进一步改进。此研究可获得免受大气气氛影响和工艺参量限制的试样,为获得性能更好的高比重钨合金激光立体成形件提供了帮助。     

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