新型压电三向钻削测力仪的设计与实验研究

为了克服以往压电三向钻削测力仪采用石英晶片较多,因此装配工艺很高,调试麻烦,制造成本很高的缺点,设计出只采用4片压电石英晶片就可以同时测量出钻削过程中产生的扭矩、径向力、轴向力的压电三向钻削测力仪。介绍了该测力仪的工作原理及设计方法,并对其进行静动态标定实验。实验结果表明每项指标均达到国际生产工程研究会-切削科学技术委员会规定的标准。它具有灵敏度和固有频率高,线性和重复性好的优点。且其结构简单,易装配和调试,成本较低,具有广阔的应用前景。     

一种压电式大扭矩测力仪设计与实验研究

石油钻机扭矩实时测量对保障工作安全和提高经济效益具有重要意义。针对应变式扭矩测力仪使用一段时间后精度降低问题,设计了一种压电式扭矩测力仪。其具有体积小、量程大和稳定性好等优点。首先构建了测力仪的三维模型,论述了测力仪的测量原理;然后推导了电荷放大电路输出电压与输入电荷之间的关系式,设计了高输入阻抗的电荷转换核心电路,使输入阻抗达到1014Ω,并给出了无线传输电路的具体实施方案;最后对测力仪进行了静态标定,其非线性为1.17%,重复性为0.46%。该压电式扭矩测力仪性能指标达到了钻机扭矩实时监控的要求。     

双向转角电磁铁输出扭矩特性仿真分析

基于电磁场有限元仿真,探讨了双向转角电磁铁的工作机理,分析了其输出扭矩特性.针对工业应用中,双向转角电磁铁在0°位置启动时,需要较大启动电流,且在0°～90°范围内提供的输出扭矩较小,为了获得较大输出扭矩,确定最佳工作区,采用电磁场有限元分析软件Maxwell 2D/3D,对不同安匝数的双向转角电磁铁进行瞬态仿真计算,得到电磁铁转子旋转180°过程中各角度的磁场分布以及输出扭矩,探讨了其实现双向旋转的工作机理.仿真结果表明:双向转角电磁铁的最佳工作区在40°～～140°之间,输出扭矩会随着线圈安匝数的增多而增大.该仿真结果为双向转角电磁铁的工业应用提供了依据.     

三向压电式动态车削测力仪的性能研究

基于压电式动态车削测力仪在测试过程中信号的动态监测与结果分析,采用有限元法对测力仪结构进行了热结构分析,得出其在切削热作用下温度场分布,同时采用模拟实验的方法对有限元分析结果进行了验证。从而得出测力仪在动态测试时,切削热对其性能的影响规律。两种方法均证明了切削热对压电车削测力仪的影响,为改进测力仪的结构提供了理论基础,对改善测力仪的性能起到了很好作用,可广泛用于传感器弹性元件优化设计工程。     

基于归一化标定的压电测力仪测试精度研究

分析归一化标定时,加载力偏差对压电测力仪矢量力测试精度的影响。通过对理论推导可得,归一化标定加载偏差使电荷放大器归一化灵敏度改变,并增大了横向干扰输出,导致测力仪对矢量力测量产生偏差,降低了测试精度。通过实验对小力值矢量力进行测试,调整加载杆连接方式减小加载力偏差,测力仪横向干扰降低38.8%以上,矢量力参数不确定度最多减小53.9%。     

采用不同材料坩埚对碲锌镉晶体质量的影响

文中采用热解氮化硼(pBN)坩埚生长Cd0.96Zn0.04Te单晶体,并与采用内壁涂碳的石英坩埚生长的晶体进行了对比分析.本文获得的晶体尺寸为φ455mm×110mm,(111)衬底晶片面积最大可达40mm×30mm,测试分析结果显示:Everson腐蚀坑密度小于2×104cm-2,且分布均匀,无网络状分布结构,与石英熏碳坩埚相比,结构质量有了明显提高;第二相夹杂物尺寸小于2μm,密度为0～1×103 cm-3;(111)B晶片的X-ray反射貌相图显示,晶体的结构均匀,完整性较好.上述晶体质量评价指标均优于采用石英熏碳坩埚生长获得的晶体,而且更为重要的是,上述各项指标在同一晶锭的各晶片上基本重复,这说明了单晶具有良好的均匀性,有利于生长均匀的碲镉汞外延层.     

压电石英晶片扭转电荷灵敏度分布规律的研究

为提高压电扭矩传感器的检测精度,应用张量坐标变换原理对石英晶片扭转电荷灵敏度分布规律进行了研究.首先根据各向异性材料力学和电磁理论阐述了石英晶片在扭矩作用下的扭转应力和极化电荷,从而得到电极检测的电荷量仅与压电系数d34有关；利用张量坐标变换原理求出在新坐标系中的压电系数d34,进而得出扭转电荷灵敏度随电极分割线绕y轴旋转角α呈余弦规律变化.实验结果表明理论分析与实测完全吻合.该研究将为新型扭矩传感器设计中检测电极的粘贴奠定工艺基础.     

轴向压缩悬臂梁压电双晶片动静态特性研究

研究施加轴向压缩力于悬臂梁压电双晶片端部以增大端部输出位移和力的问题,对其进行了有限元分析,并推导了弹性力学解析解及模态方程,得到了符合程度较好的结果。研究结果表明,在120V电压及5.5N轴向力作用下,端部阻塞力达0.25N,输出位移较原来增大3倍以上(达5mm),而一阶特征频率随轴向力增大而加速减小。当轴向力达到一阶临界屈曲时,一阶特征频率趋于0,但当轴向力取一阶屈曲力的70%时,其1阶固有频率仍有45Hz,相较于普通伺服舵机有较大的优势,可有效提高微小型飞行器的操稳性。     

等强度梁表面应变分布光纤测量实验

基于光频域反射技术(OFDR)原理的分布式光纤测量技术,研究聚酰亚胺光纤在等强度梁表面不同布线方式下测量应变的准确性。聚酰亚胺光纤分别与梁的长度方向平行、垂直、呈45°角及绕成直径为?50 mm的圆粘贴,测量梁表面应变分布,测量结果同时与应变片及理论值对比,研究光纤在非轴向应力作用和弯曲下的轴向应变分布测量结果,误差小于1%。实验结果表明,基于OFDR原理的光纤技术可实现结构表面应变分布式连续准确测量。     

粒子的轴向位移对光阱力学参数标定的影响

作为力探针的光阱有两个重要参数，在垂直光束轴的横向上的刚度和逃逸力。对它们的标定精度直接影响到光阱测力的精度。利用信息熵方法，研究了基于流体力学法标定的光阱刚度和光阱逃逸力。结果表明，光阱中的小球在不同横向速度的水流作用下，不仅有横向位移，而且有不同的轴向位移，即所标定的光阱刚度不是同一水平面的光阱刚度，而是一定轴向范围内的平均横向刚度。这是流体力学法标定光阱横向刚度的主要误差来源之一。在逃逸速度下小球从光阱中沿轴向向上逃逸，所以这样测得“代表光阱的捕获能力的参数——光阱逃逸力”只是在轴向逃逸的临界条件下的横向光阱力（等待此时的横向粘滞力），小于最大横向阱力。     

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