双向反射分布函数测量装置设计及指向精度分析

为实现对样品的双向反射分布函数（Bidirectional Reflectance Distribution Function,BRDF）的测量,设计了一种少光线遮拦、大回转半径和高定位精度的测量装置。根据测量空间和角度需要,设计了大回转半径（1.3 m）的方位圆环轨道和天顶弧形轨道。轨道外侧安装同步齿形带,采用伺服电机驱动带轮分别实现两个方向的运动。安装在天顶弧形轨道的探测器对位于装置中心的样品在方位角180,天顶角75范围内进行探测。为避免在大尺寸结构下的运动卡滞,设计了基于弹簧预紧的防卡死机构,并对机构引入的指向精度进行误差分析,最后对测量装置的指向精度进行了测量。实验结果表明:BRDF测量装置方位轨道指向精度优于0.147,天顶轨道指向精度优于0.358,测量结果与分析结果相符,验证了所设计的BRDF测量装置能够满足指标要求。     

FASTRAK在高密度头相关传输函数测量中的应用

高密度头相关传输函数测量对声源空间方位的精度有更高要求,因此要有精度较高的声源定位装置（系统）,并对定位系统的误差进行校准。使用FASTRAK电磁追踪器对测量高密度HRTF的定位系统进行误差校准。FASTRAK的空间分辨率为0.01°,静态精度为0.15°,经定位系统精度校准后,声源方位角误差可控制在0.1°±0.15°的范围内。文中测量高密度HRTF数据库的最小方位角间隔为2.5°,上述误差基本满足测量要求。     

采用低发射率涂层的发动排气系统红外特征实验

实验测量了涡扇发动机收敛喷管排气系统模型的红外辐射强度的分布,比较了中心锥表面上涂覆低发射率涂层前后,水平平面内0°,5°,10°,15°,20°,30°,45°,60°,75°和90°方向上在3～5 μm波段的红外辐射强度.结果表明:在0°～45°范围内,中心锥表面涂覆发射率ε为0.51的涂层后排气系统的辐射强度比原...     

基于ARM9的定位定向装置设计与实现

物体位置及运动方向测量在武器装备瞄准、卫星通信、深空通信领域具有广泛的用途,物位物移要求为地理信息.利用电子罗盘,直接测量采集到的信息为地磁场信息,即磁方位数据,经过磁偏角修正,得到地理方位数据:利用GPS采集位置信息,通过位置信息、时间信息查询磁偏角,修正状态信息,进而达到准确获知物体位置状态的目的.该装置经过磁偏角信息修正,可以到达电子罗盘方位测量精度.在通过位置信息修正方位信息,得到精确方位数据应用上具有创新性.     

基于两次多项式拟合的人眼注视方向估计

针对单相机、无辅助光源的人眼视线估计系统固有的精度低、头部运动受限等问题,本文提出了基于两次多项式拟合的、单相机、单辅助光源的视线估计方法。在准确提取辅助光源在角膜表面产生的反射光斑和虹膜中心的基础上,以反射光斑为基准点考察虹膜中心相对于反射光斑的偏移与注视点之间的映射关系。首先通过第一次多项式拟合考察注视点不变而反射光斑位置发生变化,对虹膜中心与反射光斑相对位置的影响,以此确定相对于任意位置的反射光斑,对应测试板上15个测试点的理想虹膜中心偏移。然后通过第二次多项式拟合考察当反射光斑在图像中的位置确定后,虹膜中心偏移与注视点之间的对应关系。通过两次拟合,实现了人眼注视方向的有效估计,在允许头部自由运动的前提下,测试样本的水平方向平均注视误差为1.31°,竖直方向平均注视误差为1.00°。     

圆锯片几何参数的精密视觉测量

分析了圆锯片的几何参数测量原理,开发了圆锯片几何参数测量软件.在图像处理的基础上,计算了圆锯片内圆孔直径、圆度误差、外圆直径、齿尖角、径向前角及径向后角.通过标准样件对被测零件进行标定.对圆锯片内圆孔提出了改进的二次多项式插值亚像素定位方法,提高了检测精度.对齿尖两段直线采用改进的最小二乘法进行拟合,拟合误差是常规最小二乘法的1/4.利用亚像素方法测量时,内圆孔直径为25.204 mm,圆度误差为0.005 mm,外圆直径为193.624 mm,齿尖角为59.999°±0.00695°,径向前角为15.004°±0.0104°,径向后角14.997°±0.013 7°.将待测的6个参数集成测量是该系统的特色,整个测量过程不足1 s,达到了高速、精密的测量要求.     

S波段圆波导缝隙全向天线的设计

设计了一种S波段圆波导缝隙全向天线,该天线是在圆波导柱面上开凿一定数量的纵列缝,组成缝隙阵列。经过仿真优化设计和测试,天线在360°方位面范围内幅度起伏小,具有很好的全向特性,目前天线已成功地应用到了雷达产品中。     

新型Ku频段全向微带阵列天线

设计了一种新型Ku频段全向天线,该天线由双面辐射微带阵列组成,通过串联形式馈电,实现了全向中等增益辐射特性.文中给出了微带阵列天线的设计方法,对该微带阵列天线的阻抗带宽特性、方向图特性和馈电结构进行了分析.结果表明,该微带阵列天线反射损耗小于-10 dB的绝对带宽为1.15 GHz,在可用频带内全向增益为6.8 dB～7.3 dB,E 面波束宽度在20°～24°,H面方向图不圆度在±0.5 dB以内.该天线能够满足微波通信系统要求.     

激光来袭方向探测与告警系统的设计

为了探测敌方激光的来袭方向,开发了一种激光脉冲方向告警系统.该系统由光学模块、信号处理模块和显示模块组成,其探测范围为水平方向0°～360°,垂直方向0°～90°,角度分辨率30°,识别出波长为0.85,1.06和1.54 μm,脉宽不小于10ns的激光脉冲,探测功率密度下限为1 mW/cm2,其探测概率达到98%以上...     

基于单相机双光源的视线估计

提出一种角膜反射和虹膜中心估计算法相结合的视线估计方法,使用单相机、双辅助光源构建了头部可自由运动的视线估计系统。在准确提取两个反射光斑位置和虹膜中心坐标的基础上,以多项式函数的形式建立视线特征向量与测试屏上注视点坐标之间的映射关系。实验结果表明,系统在水平方向上视线估计的平均误差为0.91°,在垂直方向上平均误差为1.1°,达到了良好的视线估计效果。     

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