红外双色单站被动定位方法

设计了合作目标与非合作目标的红外双色单站被动定位算法, 通过实例计算的方式证明了该方法的正确性与有效性。分析了双色消光系数差异大小以及目标温度高低对测距定位性能的影响, 得出双色消光系数差异越小、目标温度越高, 越有利于测距定位的结论。结果表明: 对于1000K以上的目标, 选择0.75～3/3～5μm这两个大气窗口作为工作波段, 在20km以内都可很好地实现测距定位; 对于500K以下的物体, 即使在5km的范围内, 测距定位效果也较差。     

目标红外辐射双色比值的大气传输研究

空中目标的红外辐射在大气中传输时 ,大气以及大气中的气溶胶会对红外辐射产生吸收和散射 ,从而造成红外辐射的衰减。大气对红外辐射的衰减程度可以用消光系数来描述 ,波长不同 ,消光系数也不同。红外系统测量到的目标红外辐射的双色比值也会随目标距离变化而变化。由测量到的目标在两个波段的红外辐射 ,通过一定的信号处理手段 ,可得出目标的距离、双波段红外辐射能量、红外双色比值等信息 ,以此对空中目标的识别和定位。推导了利用大气消光系数获取空中目标距离信息和红外辐射信息的公式 ,画出了典型空中目标双色比值的大气传输图。     

飞行器尾焰红外辐射及其被动测距

旨在研究利用飞行器的尾焰辐射对飞行器进行被动测距。导弹和飞机发动机的排气系统是飞机在3~5 m波段的主要红外辐射源。建模计算了矩形喷管尾焰红外辐射特性,计算结果表明,不管观察方向如何,尾焰红外辐射强度色比是相同的。当辐射强度色比在大气中传输时,因为吸收和散射而被衰减,不同波长上红外辐射衰减幅度不同,辐射强度色比随着传输距离的改变而发生变化,色比包含了目标的距离信息。推导了目标尾焰色比与尾焰温度、辐射传输距离、大气消光系数之间的关系。计算了尾焰色比与尾焰温度的关系,推导出了红外三色比距离方程组,选取4.5、4.6、4.7 m三个波长对三色被动测距进行了研究。利用测距方程组画出了测距图。结果表明,利用该方法可对尾焰进行三色测距。     

目标红外辐射双色双值的大气传输研究

空中目标的红外辐射在大气中传输时，大气以及大气的气溶胶会对红外辐射产生吸收和散射，从而造成红外辐射的衰减。大气对红外辐射的衰减程度可以用消光系数来描述，波长不同，消长系数也不同。红外系统测量到的目标红外辐射的双色比值也会随目标距离变化而变化。由测量到的目标在两个波段的红外辐射，通过一定的信号处理手段，可得出目标的距离、双波段红外辐射能量、红外双色比值等信息，以此对空中目标的识别和定位。推导了利用大气消光系数获取空中目标距离信息和红外辐射信息的公式，画出了典型空中目标双色比值的大气传输图。     

红外双波段点目标双色比分析与处理

红外双色比能够表征目标的温度信息,但点目标双色比受噪声、探测器盲闪元以及跨像元因素干扰,难以准确测量,影响测温精度。应用递归图法定性分析和判断了点目标双色比的非平稳性。针对这一特性,先对点目标信号应用移动平均滤波做预处理,再通过小波软阈值去噪对双色比进行降噪处理。试验结果表明,在信噪比大于12的条件下,该方法可以实现静态点目标1 K温度分辨率,慢速动态点目标2 K温度分辨率。     

钠钙玻璃的变温太赫兹色散特性研究

研究钠钙玻璃在不同温度下折射率和消光系数随频率的变化规律。利用时域光谱(TDS)系统测定了钠钙玻璃温度在87~520 K范围内、频率在0.1~1.5 THz范围内的色散曲线。通过使用Cauchy公式拟合不同频率对应的折射率和消光系数,经验证与实验值符合较好。通过添加温度修正项,可以很好地拟合较大范围内的色散曲线。得到一种求解不同温度不同频率下钠钙玻璃折射率和消光系数的方法。     

双目立体实时测距系统的关键技术研究

基于双目视差测距原理,建立了一个被动测距实验系统。围绕提高测距系统的测距精 度、准确率、速度和抗干扰性能等,研究了图像预处理、配准算法、搜索策略等关键技术。提出了改进的互积相关配准测度,并采用粗、精配准相结合的搜索策略以及抛物线拟合方法,实现了快速双目立体目标测距。实验证明该测距算法可有效地抑止噪声、双目光强和图像对比度差异等因素的影响;测距系统测距精度高、稳定性好、实时性好,对于10km目标相对测距误差小于4% ,响应时间小于0. 5 s。     

杂乱光程波动对激光测距精度的影响

本文检验了扰动感应光程长度波动对单色和双色激光测距系统的影响。用几种建议的模型推导出光程偏差的相关和结构函数随高度作C_n~2变化。对于单色系统来说,当扰动很高(C_n~2～10~(-13)米~(-2/3)),有效传播光程较长(>10公里)时,杂乱光程长度波动会把测距精度限制到几厘米。双色系统对杂乱光程波动可作部分校准,使精度在大多数情况下限制到几毫米。然而在低仰角卫星测距(<20°)和超长水平光程时,双色.系统也会使误差达到几个厘米。     

基于GDOP的红外跟踪系统双站交汇测距能力分析北大核心CSCD

分析了红外跟踪系统双站交汇测距理论,引入GDOP作为交汇测距精度评价指标,对红外跟踪系统测距精度进行了仿真,得到了不同条件下测距误差。结果表明:双站交汇测距误差与红外跟踪系统自身的测角精度、目标位置、目标距离密切相关。给定条件下,方位角20°时,5 km~60 km范围测距误差在1.5%~24%之间逐渐增加;方位角90°时,5 km~60 km范围红外跟踪系统测距误差在1%~8%之间逐渐增加。     

瑞利散射激光雷达强光感生噪声修正的新方法及大气温度探测

借助一套全新的地面高精度光电探测器强光感生噪声检测平台,建立了强光感生噪声精细结构扣除模型,同多通道信号接收技术相结合,改进了一台用于中高层大气温度探测的子午工程双波长三通道瑞利散射激光雷达数据的处理方法。处理后数据反演的大气温度廓线与TIMED卫星结果相比较,得到了很好的吻合。在35~85km高度范围内二者反映了较一致的温度分布特征,30~55km温度误差小于±5K,55~75km温度误差小于±10K。     

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