DDQ新式扬声器——低频扬声器新进展

DDQ低音是由若干组呈“V”型设置的音盆串联组成发声体.在发声体两端设有驱动器,每组相邻的音盆通过两根高刚性传导杆分别连接于设于两端对应的驱动器.每组相邻音盆分别由驱动器及传导杆驱动,随音频信号将腔内的空气挤出或吸入而发声.传导杆由若干断面呈圆形或矩形的空芯高刚性长杆并联组成,具有轻质高刚性和适度阻尼的特点.在音盆中部设有矩形结合孔和矩形通过孔,结合孔用于连接传导杆,通过孔用于通过传导杆.     

碳纤维复合材料天线反射面研制

碳纤维复合材料产品具有轻质、高强度、高刚度等特点。本文介绍了新型碳纤维复合材料天线反射面的研制过程,并详细叙述了该天线研制工艺中的关键技术。     

基于THz-TDS的碳纤维复合材料无损检测

基于反射式THz-TDS成像技术对碳纤维缠绕增强复合材料缺陷进行无损检测实验,获得不同缺陷碳纤维样品的成像结果及数据。结果表明,反射式THz-TDS成像技术在0.1～3.5 THz波段对碳纤维复合材料中的热损伤、划伤缺陷、磨损缺陷及孔洞缺陷成像清晰,分辨率较高;且获得的时域波形对样品热损伤缺陷敏感,适用于局部检测对整体性能的判断。     

碳纤维复合材料天线反射面研制

碳纤维复合材料产品具有轻质、高强度、高刚度等特点，本文介绍新型碳纤维复合材料天线反射面的研制过程，并叙述了该天线研制工艺中的关键技术。     

一种宇航用光缆及光缆组件的加固设计方案

由于光缆较柔软,在工程操作时容易弯折,使得装备在航天器舱内的光缆弯曲半径过小。为增强光缆的刚性,提出了一种宇航用光缆及光缆组件加固设计方案,在不改变光缆结构的前提下,按原生产工艺将光缆组件制作完成后,采用胶带和布进行缠绕保护,并对光缆组件的相关性能进行试验分析。试验结果表明,该方案增强了光缆组件整体的刚性,满足设计要求。     

离轴三反空间相机外遮光罩组件的研制

杂散光抑制对提高空间相机的成像品质起着至关重要的作用。通过合理地设置外遮光罩可以有效地抑制杂散光。为了满足空间相机外遮光罩轻质、高刚度、高强度和高尺寸稳定性的要求,选取增强基碳纤维复合材料作为空间相机外遮光罩的材料,并提出了相机主支撑结构与外遮光罩独立安装的设计思想,从而最大限度地降低了外遮光罩变形对光学元件尺寸稳定性的影响。利用有限元分析技术对外遮光罩结构进行了热特性及动态特性分析,并对结构参数进行了优化设计,最终得到了质量为5.2kg、一阶固有频率为113Hz的外遮光罩结构。动力学试验测试结果表明,外遮光罩一阶谐振频率为106.8Hz,在正弦振动和随机振动试验中加速度放大倍率小于10倍,最大应力为86.6MPa,远远小于碳纤维复合材料屈服应力,结构刚度、强度完全满足设计指标要求。     

Powerlink运动控制网络用于碳纤维制造

据报道,瑞士一家碳纤维生产企业Carbo—Link公司最近研制了一台基于以太网Powerlink运动控制网络的缠绕设备,用于生产竞技类运动所需的多种碳纤维零部件。目前,这台设备已投入使用并取得了很好的效果,能够处理多种不同的碳纤维产品。Carbo—Link公司也在等划再研制一个50米的版本,以支持更多的应用。     

空间相机碳纤维承载舱的动态设计

为了满足空间相机在装星时的空间位置要求,并避免空间相机与星体之间的共振,设计了空间相机的承载舱。该设计采用了具有优良力学与工艺性能的碳纤维材料以及具有合理拓扑形式的桁架结构。采用计算机仿真试验和三次样条插值法对承载舱的杆截面尺寸进行了优化。结果表明,当杆截面尺寸为28 mm×28 mm×3 mm时,承载舱的动态特性和整体质量满足设计要求。     

多层微带天线复合成型工艺技术研究

主要介绍了多层微带天线在复合成型过程中对结构板与电气板的变形控制以及材料的电性能匹配设计.提出采用高模量碳纤维层压板作为蜂窝夹层结构面板并按"零膨胀"理论进行铺层设计,选用低损耗介质、低热膨胀系数和高力学性能的轻质泡沫材料及粘接胶膜,并使用特种工装设备将多层微带板、多层泡沫材料和结构板复合粘接在一起,最后采用真空袋加压的工艺方法复合固化成型.     

高分子结晶材料——碳纤维在扬声器中的应用

前言在1974年底到1975年初,我们对扬声器的关键部件——纸盆,进行了研究和探索,采用了一种高分子结晶材料——碳纤维,使纸盆结构有了显著改进。新纸盆不仅刚性(或机械强度)大大提高,同时实现了轻量化。碳纤维纸盆扬声器的试制品,经上海电器科学技术研究所测试,与不加碳纤维的扬声器相比,平均灵敏度提高1.5dB以上,接近国外资料报导的1.6～2.0dB的水平。一、扬声器纸盆和碳纤维扬声器是电声传输系统中比较薄弱的环节,往往由于扬声器性能不好而影响了重放音质。因为声信号的频率范围很宽,多达九、十个倍频程,要让机械系统在这么宽的频段内无失真地重放原音,是相当困难的。近年来,国际上致力于提高磁通密度(采用高级合金钢)和减轻纸盆等措施来改进扬声器的音质。目前,国内扬声器的生产中也同样存在纸盆刚性不好的问题,在振动中容易引起     

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