多物理场下望远镜主次镜失调分析研究

为满足光电跟踪设备的设计精度要求,减小并评估主镜筒变形对主、次镜位置相对变化的影响,利用Ansys Workbench有限元分析软件对主镜筒进行了热稳态分析、静力学分析以及多物理场耦合分析。分析出了主镜与次镜的偏转角,对主镜筒结构提出了相关修改意见。通过仿真所得的结果可知,主镜筒因太阳照射不均而产生的弯曲变形对反射镜的偏转影响最大。为减小反射镜的偏转,将次镜由镜筒支撑改为由次镜支撑架支撑,并加固次镜与调焦机构间的支撑连接。再次对修改后的主镜筒进行了处于水平、上仰45°、上仰90°时的静力学分析,对主镜筒进行了温度场与重力场耦合的多物理场分析。仿真所得的反射镜偏转角度数据将为光电跟踪设备的实验标校提供一定的参考依据。     

库德光路的五棱镜安装方法

为实现库德光路的快速高精度装调,提供了一种基于自准直原理的五棱镜安装方法,给出了库德光路的原理和安装方法,并对组装后的库德光路进行误差分析。得出应用此方法安装库德光路的光学静态误差在15″以内,满足一般库德光路的技术要求。因此,此方法不仅可以适用于库德光路,对反射镜的安装也有一定的借鉴和参考。     

库德光路光束指向稳定性分析

库德光路光束指向稳定性是保证激光测距机光轴指向精度的关键因素,通过坐标变换建立了一种可以从空间角度表征光束指向稳定性的动态方法,解决了大型激光测距机库德光路系统误差对光学系统影响的问题,将库德光路系统误差与光束指向有机地结合起来,以某地平式激光测距机为研究对象,建立了库德光路光束指向的动态误差模型。将CCD 固定在库德镜5 的安装接口处,并与图像采集卡组成图像采集系统,直接对库德光路激光光斑进行采集,获得了精度较高的光束指向动态误差数据。利用实测数据对光束指向的动态误差模型进行了最小二乘拟合,由此标定出了该设备库德光路光束指向的动态特性,为设备系统误差的修正工作奠定了基础。     

500mm口径星地激光通信地面接收端系统设计

为提高星地激光通信地面接收端探测灵敏度和分辨能力,减少信标光捕获时间和难度,基于星地激光通信链路和设计方案,结合自适应光学（AO）技术,设计了一套500 mm口径的星地激光通信地面接收端系统。该系统采用库德光路、共口径分光探测形式,包含卡塞格林天线、倾斜镜精跟踪、AO超精跟踪、AO波前探测等4个单元。天线物镜组采用同轴卡塞格林结构,结合折射镜组构成开普勒望远结构,兼顾体积和长出瞳距的需求。在精跟踪倾斜镜和AO倾斜镜之间设计了4f系统,解决校正光轴时的瞳面漂移问题。在波前探测器和变形镜之间设计了双远心系统,构建两者共轭关系,降低波前探测的轴向误差影响。采用光学被动式方法对4个单元进行消热差设计,提高系统温度适应性。最终实验结果表明：在10℃～30℃范围内,各单元波像差均优于1/10λ（λ=632.8 nm）,满足设计要求,具有一定借鉴价值和工程意义。     

1m太阳望远镜光轴变化检测与改正

针对1m太阳望远镜主光学系统光轴与其光电导行系统光轴在望远镜跟踪过程中的相对变化对光电导行跟踪精度的影响,从望远镜的光机电系统结构出发,分析了光电导行闭环跟踪时光轴变化引入的跟踪误差变化规律,提出了光轴变化的检测方法。经过实测表明,光轴的最大相对变化是46″,且变化只与望远镜指向的高度角有关,与望远镜指向的方位角无关,结构重力变形是引起光轴变化的主要因素。在光电导行系统中引入光轴变化的软件修正模型来改善光轴变化引起的光电导行闭环长期跟踪误差。     

离轴抛物面镜在温度传感器校准系统中的应用

为了改善温度传感器动态校准系统中的晶体透镜对激光束的聚焦效果,使用离轴90°抛物面镜代替晶体透镜对系统进行了改造,通过几何光学方法,对离轴90°抛物面镜应用于激光聚焦光路时的光轴的角度失准对聚焦光斑造成的影响进行了分析,并利用改进后的系统对CHAL-010型热电偶进行时间常数测试和动态校准实验,得到了CHAL-010型热电偶在温度阶跃为242℃左右时的时间常数值,完成了该热电偶的动态校准.结果表明,采用离轴90°抛物面镜代替温度传感器动态校准系统中的晶体透镜能达到温度传感器动态校准的目的.     

机载激光测照器发射光轴不稳定度仿真分析

针对某型无人机机载激光测照器,分析了导致激光发射光轴产生偏离的原因,然后使用CAE软件ANSYSWorkbench分别对受安装力、热和振动等因素影响下的结构形变进行仿真,通过谐振腔光路和扩束光学相关公式计算得到激光发射光轴的最大综合偏转角,从而确定出激光测照器的发射光轴不稳定度,以验证设计是否满足相应可靠性指标要求。     

星敏感器支架的结构/热稳定性分析及验证

为明确星敏感器支架受空间环境影响产生的变形对星敏感器定姿精度的影响,对星敏感器支架的结构/热稳定性进行了研究。通过有限元法对星敏感器支架进行刚度分析,将热分析获得的在轨极端工况下的温度数据映射至结构模型上计算得到热变形,利用最小二乘法得到各星敏感器光轴矢量,最后进行试验验证。结果表明:星敏感器组件的结构基频为429 Hz,与分析结果相差不超过2%,试验前后星敏感器光轴与基准坐标系各轴夹角最大变化不超过5;在轨期间星敏感器支架最大温度波动小于2 ℃,星敏感器光轴变化最大为4~5,与分析结果一致。星敏感器支架的结构/热稳定性良好,能够满足星敏感器定姿精度要求。     

离轴四反射镜光学系统设计

与一般光学系统相比,航空遥感光学系统具有长焦距、大口径、宽波段等特点。因此,广泛使用反射式光学系统。常见的离轴三反系统已不能满足系统小型化、轻量化的要求。介绍了一种无中心遮拦的离轴四反射镜系统,由离轴三反系统改进而成,结构更加紧凑。带一次中间像面的离轴三反系统的中间像位于次镜和三镜之间,为了进一步折叠光路,在中间像面处加入球面反射场镜,从而成为离轴四反。分析了离轴四反的设计步骤,设计了一个焦距为1 200 mm,视场为0.8°×0.8°,相对孔径为F/6的光学系统,系统总长只有300 mm,并达到很好的光学性能,具有长焦距、小尺寸、良好的杂散光抑制能力等特点。     

高集成度四视场中波红外光学系统

为了实现超小型化、长焦距和超大视场,提出并设计了一种高集成度四视场中波红外光学系统。该系统采用双光路结构形式,包括超小视场光路和小/中/大视场光路,两支光路共用中继组;对超小视场光路进行了四次立体折叠,并对小/中/大视场光路进行了二次折叠。通过以上六次折叠,整个双光路光学系统的外形尺寸得到了有效约束,其外形包络在242 mm×150 mm×85 mm (局部125 mm)范围内,系统集成度高。这种双光路光学系统包括超小视场、小视场、中视场和大视场四个视场。其中,超小视场的焦距为688 mm,视场为0.8°;大视场的焦距为13.19 mm,视场为40°,实现了长焦距和超大视场并存,并获得了50×的变倍比;超小视场光学系统仅采用5片透镜,透过率高,并具有光学被动消热差设计;整个双光路光学系统结构紧凑,体积小,实现了超小型化。设计结果表明,该光学系统像质良好,可以满足高性能热像仪的使用要求。     

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.     

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     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.