弛豫铁电单晶超声电机的动态响应模拟与分析

相对于传统压电陶瓷,新型压电单晶材料铌镁酸铅-钛酸铅(PMNT)具有更优良的介电和压电性能。该文将PMNT单晶作为超声电机的驱动材料,引入二维弹性接触、预应力等因素建立数学模型。经Matlab软件对20mm超声电机进行模拟,其最大空载转速为383r/min,输入电压频率为50.3kHz。经过与实测结果对比,该模型能够较准确地模拟电机稳态运行时的性能参数。     

探讨超声电机用压电陶瓷

简要介绍超声电机的工作原理及对压电陶瓷的性能要求，分析了3种压电陶瓷材料对超声电机性能的影响，确定了用于超声电机的压电陶瓷材料的性能指标，并对压电陶瓷材料的制备工艺进行了探讨性研究．     

基于MEMS与压电陶瓷钎焊的微型超声电机

面向超声电机定子的一体化与微型化需求,提出了一种基于钎焊与微电子机械系统(MEMS)工艺的微型超声电机定子。对超声电机的原理和结构进行分析,利用有限元法对定子的模态与谐响应进行了仿真。利用钎焊工艺将锆钛酸铅(PZT)压电陶瓷与金属弹性体进行连接,通过MEMS与机械加工工艺对定子的驱动足、上电极等进行制备。对超声电机定子焊接情况进行表征,对超声电机的振动性能与驱动性能进行测试。测试了PZT压电陶瓷与金属弹性体的结合强度,两者之间的抗剪切强度为33.46 MPa,观察了焊接截面形貌,可看出各焊接层厚度均匀,无裂缝、孔隙。搭建实验平台对定子的振动性能与驱动性能进行了测试,微型超声电机的定子的谐振频率为188.15与266.16 kHz,最大振幅为228 nm,在激励电压为30 V、预压力为350 mN时,微型超声电机的最大速度为38.22 mm/s。实验结果表明,该超声电机定子钎焊情况良好,驱动性能较高,具有广阔的应用前景。     

微小型驻波超声电机定子振动特性的仿真分析

针对直径10 mm的两种驻波型超声电机定子的振动特性进行有限元仿真分析。利用ANSYS有限元软件建立定子的有限元模型,进行了振动模态及谐响应的仿真分析,获得定子的主要振动模态、模态频率及振幅。探讨了2种压电陶瓷及定子长度对其谐振频率和振幅的影响。研究结果表明,驻波型超声电机定子上斜槽或斜齿结构可实现模态转换,是实现电机驱动的关键。在分析的两种驻波型超声电机的8个定子中,采用PZT4压电陶瓷材料、长度16 mm的斜槽式超声电机定子的振幅值最大。     

小型压电式超声微幅振动试验台的分析与设计

通过对压电直梁弯曲振动特点进行分析,用有限元分析软件设计出一种结构简单的小尺寸压电式超声微幅振动试验台.该试验台主要由压电直梁、T字型台面及两端附加质量组成,利用压电直梁的奇数阶弯曲振动模态实现梁中间处的台面在竖直方向上的简谐振动.样机的测试结果表明,试验台输出频率涵盖范围广,台面振幅分布均匀度较好和振动幅值精度较高,可作为一种实验平台用以研究超声电机及超声振动输送(给料)中的动态接触问题.     

超声减摩用压电换能器阻抗匹配的试验研究

对超声减摩特性已进行了一些研究，实验结果表明，当超声振动的振幅越大超声振动的减摩性越好。因此，要使减摩效果达到最好，应使压电振子在谐振点附近工作，使其振幅达到最大。该文讨论了压电换能器的各种匹配电路及其匹配关系并进行了相关实验；结果表明，选择合适的匹配方法，能有效提高压电换能器的性能．     

杆式行波超声电机紧固力的实验研究

以提高一种杆式行波型超声电机性能为目标，对电机定子的结构进行了介绍，强调了定子的紧固力对压电陶瓷及电机本身性能的重要性。介绍一种电机定子紧固力的间接加载方法和PSV-300F-B型高频扫描激光测振系统工作原理及其使用方法。通过实验，得出电机定子的紧固力与定子的一阶弯曲共振频率、工作端面的最大振幅及其振动速度的关系。经过权衡多方面因素，确定本电机的最佳紧固力约为3900N，此时压电陶瓷片承受的压应力为21．3MPa。     

三种弯曲旋转超声电机的原理及研究

介绍了三种不同结构的弯曲振动模态超声微电机。详细讨论了它们共同的驱动原理，分别介绍了压电片夹心式和压电管式电机的结构特点及性能测试。在此基础上，研制了一种更易实现微型化的压电柱式超声微电机，并介绍了它的极化原理及结构。文章对弯曲振动模态超声电机的设计具有指导意义，对其深入研究具有参考价值。     

单相短柱型直线超声电机的设计

提出了一种单相驱动的立式短柱型压电直线超声电机,论述了该电机的动作原理和设计过程。该电机利用纵向振动和横向振动的耦合模态工作。为获得同一驱动频率的一致的双向运动特性,该电机采用对称结构,利用压电陶瓷在短路和开路时弹性模量存在差异的特性,用单相驱动信号实现了纵向和弯曲耦合模态的有效激发。以增大电机弯曲振动模态前后振幅比为目标,利用三自由度集中质量的简化模型,优化了定子的结构。制作了电机的原理样机,对其进行了输出性能测试。实验结果表明,电机的输出性能良好。电机定子长22mm,自重3.3g,0.3N输出推力下最大速度达140mm/s,5N预压力下最大输出推力近1N。     

单相短柱型直线超声电机的设计

提出了一种单相驱动的立式短柱型压电直线超声电机,论述了该电机的动作原理和设计过程。该电机利用纵向振动和横向振动的耦合模态工作。为获得同一驱动频率的一致的双向运动特性,该电机采用对称结构,利用压电陶瓷在短路和开路时弹性模量存在差异的特性,用单相驱动信号实现了纵向和弯曲耦合模态的有效激发。以增大电机弯曲振动模态前后振幅比为目标,利用三自由度集中质量的简化模型,优化了定子的结构。制作了电机的原理样机,对其进行了输出性能测试。实验结果表明,电机的输出性能良好。电机定子长22 mm,自重3.3 g,0.3 N输出推力下最大速度达140 mm/s,5 N预压力下最大输出推力近1 N。     

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