海空背景下目标温度场远距离测量研究

红外热成像系统在靶场试验中具有广泛应用,利用热成像系统对海空背景下舰船目标的辐射温度测量是获取舰船辐射特性的重要途径。根据海面舰船目标的辐射特点,考虑海面背景和天空背景的红外辐射、红外辐射在大气中的衰减及程辐射,对3～5μm和8～14μm 2个红外波段目标温度测量进行了分析。     

大气与环境影响分析的红外比色测温方法

传统的比色测温法通常利用可见光和近红外波段,对距离较近的高温目标具有较高的测量精度,而对距离较远的中低温目标无法精确测量。针对传统比色方法适用局限性,提出考虑大气和环境影响的红外比色测温方法,建立基于中波红外相机的比色测温实验系统。首先使用标准黑体进行中波红外相机和比色系统单波段定标;然后推导加入环境辐射参数的比色测量模型,进而建立新的目标辐射亮度比值与目标温度间的函数关系;最后,进行了实验室内自制灰体目标温度测量实验,验证了提出方法的可行性。实验表明:在实验温度范围内,温度绝对误差和相对误差分别小于4 ℃和6.7%,目标辐射亮度测量精度高于10%,考虑大气与环境影响的比色测温方法可实现中低温目标温度精确测量。     

天空背景红外辐射亮度测量及其对目标探测的影响分析

天空背景的红外辐射特征对目标侦察探测具有重要意义。利用3μm~5μm中波、8μm~12μm长波红外测量设备对天空背景红外辐射亮度进行了测量,长波波段辐射亮度在3.7~13.6 W?m-2?sr-1,中波波段辐射亮度在0.05~0.48 W?m-2?sr-1,相同条件长波辐射亮度高于中波辐射亮度1~2个数量级;随着观测角增大,天空背景辐射亮度显著降低,同时太阳辐射、大气温度等因素也对天空背景辐射有较大的影响。利用测量结果仿真分析了天空背景辐射对目标侦察探测距离的影响,结果表明当观测角由9.6°降低到1.9°时,红外搜索跟踪系统探测距离会减少41.5%~46.2%。     

红外测温精度的影响因素及补偿方法的研究

为了减少红外测温仪的测量误差,提高红外测温仪的测温精度,分析了距离、发射率和外界环境温度等因素对红外测温仪测温的影响;建立了红外测温实验系统采集测温数据,并对采集到的实验数据进行了分析验证,通过分析验证可得距离因素对红外辐射测温精度有较大的影响,并且存在一定的关系,从而为提高红外测温精度的提供了依据;设计了一套提高红外测温仪测量精度的系统,该系统能够测出被测物与红外测温仪之间的距离,根据测出的结果得到距离补偿公式,然后依据公式得出温度的距离补偿,从而得到物体的实际温度。最后分析可得,红外测温仪的测量精度能够大幅提高。     

高空远距离目标红外辐射及大气衰减模型研究

结合普朗克辐射定律,采用双波段测温法分析了高空远距离目标的温度与红外辐射。提出了一种目标投影面积的计算方法。由于是远距离探测,在考虑地球曲率的情况下提出了一种计算任意方向两点大气衰减的计算模型,并分析了不同探测距离下3~5μm和8~12μm两个波段红外辐射的衰减情况.实验结果表明,在10 km左右的高空中,目标红外辐射测量的距离可以从低空的几十公里增加到几百公里,这为进一步分析目标辐射特性提供了理论与技术上的支撑.     

红外星表在地基红外辐射测量系统中的应用

国内已知的红外星库数量有限,辐射照度、覆盖波段范围小,分布密集度低,无法满足现有地基红外辐射测量系统天文标定的需要。根据系统的探测波段考察并选取IRAS、2MASS、WISE、AKARI 4个全空域巡天计划及其生成的红外星表。综合考虑大气弥散、大气衰减的影响,分析计算系统在短波红外1~3 m、中波红外3~5 m、长波红外8~10 m的极限探测能力及在对应点源星表中的最低可探测的星等。搜索选取可供系统观测的恒星,结果显示在短波选取4 599个恒星目标,中波选取125个恒星目标,长波选取1个恒星目标,为我国现有地基红外辐射测量系统天文标定及红外星表进一步应用提供理论依据。     

热辐射测温系统中探测器非线性校正方法

热辐射测量技术中,红外探测器的非线性效应导致对目标红外辐射测量时存在一定误差.依据黑体辐射定律,理论计算得出黑体在不同温度、一定波长带宽下的热辐射量曲线,实验测得同样参数下红外探测器检测到的热辐射量.利用理论曲线对探测器的检测曲线进行修正,校正探测器非线性效应,提高热辐射测温的测量精度.     

视场超出目标的红外测温误差修正方法研究

为解决红外测温系统超出有效测温距离导致的测温精度下降问题,从红外热辐射理论出发,提出了一种视场超出目标辐射表面积的红外测温系统误差修正方法。通过计算全视场范围内的辐射照度,获得了对应的红外测温系统电压响应值。依据电压响应值与温度之间的关系,并充分考虑物体表面形貌特征,去除全视场范围内背景温度的影响,得到目标体的表面真实温度值。相对于以往的修正方法,该方法能很好地修正有效测温距离外的物体表面温度,结果与被测物体实际温度更为相近。因此,该方法极大地增强了红外测温系统的工业现场适用性。     

红外目标光谱辐射亮度测试技术

红外目标光谱辐射亮度对于武器光电系统的搜索、跟踪及目标识别都具有重要的应用。以红外辐射理论为基础,在同温度、同波长下采用红外傅里叶分光法并与标准黑体相比较的方法对红外目标光谱辐射亮度进行了测试技术研究,建立了红外目标光谱辐射亮度计量测试装置。根据实验结果分析,该装置在波长范围2.5～14 m,1 000 ℃、3 000 ℃、5 000 ℃、7 000 ℃四个温度点条件下,测量误差为1%,在5 000 ℃、7 000 ℃时,测量误差小于0.1%。分析讨论了对测量结果产生影响的因素,得出当标准黑体温度与被测红外目标温度不一致时,会给测量带来较大误差;在3.0～5.4 m范围内,分别选用InSb和MCT两种探测器,产生的偏差为0.5%。     

3～5μm红外探测器的辐射定标

在对目标进行红外跟踪测量时,为了得到目标空间位置的同时,获得其红外辐射特性数据,设计了一套红外焦平面阵列探测器的实验室辐射定标系统。以高精度的面源黑体为标准辐射源,对成像范围为3～5μm的中波红外探测器进行了响应度的标定。首先建立定标数学模型,确定定标流程;然后使用线性回归统计模型对响应度曲线进行拟合并评估,针对一般线性最小二乘法对局外点(outlier)敏感的缺点,提出Robust优化算法;最后,在外场对温度和特性已知的目标进行测量,通过实验室得到的响应度曲线和大气透过率参数进行红外辐射特性数据的反演,得到实际测量值与理论值的相对误差小于2%。结果表明,Robust优化算法能有效改善红外焦平面阵列响应度非线性引起的反演不确定度。     

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.     

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.     

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.     

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.     

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.     

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.     

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