一种激光测距机光轴平行性智能检校方法

针对发射光轴的双光楔校正结构,提出了一种激光测距机光轴平行性智能检测校正方法。建立了光轴平行性偏差量与双光楔结构旋转角度之间的数学模型,利用CCD图像传感器和数字图像处理技术得到激光发射光轴与瞄准光轴之间的平行性偏差,依据所建立的数学模型解算出双光楔需要调整的角度值,结合机械校正装置转动相应的角度,实现了激光测距机光轴的校正。该方法同样适合于其他具有双光楔调整结构的光学仪器。     

可调谐TEA CO2激光器谐振腔结构稳定性研究

针对可调谐TEA CO2激光器谐振腔光桥结构的稳定性问题,重点通过分析光桥端板受力变形情况来研究光桥端板的选材和形状。建立了光桥端板的有限元模型,利用有限元分析软件计算出不同材料、不同形状的光桥端板变形量并作比较,分析结果表明三角形铝板是比较理想的端板方案,厚度为40 mm的三角形铝板最大变形量为1.27×10-3 mm。为设计稳定的可调谐TEA CO2激光器谐振腔结构提供了理论依据。     

一种长焦大变倍连续变焦光机组件结构设计及装调

介绍了一种基于长焦大变倍比连续变焦红外热像仪的结构设计及装调方法。可用于各类红外热像仪的变焦结构设计中,在保证图像清晰的前提下,能够明显改善连续变焦过程中的光轴晃动,提高红外热像仪的光轴一致性和光轴稳定性,控制焦距精度,降低红外热像仪装调难度。该结构采用双导轨配合步进电机组件化设计,相对于其他变焦结构的设计,该结构变焦过程中光轴一致性好,光轴晃动量小,通用性强。     

激光二极管泵浦的调Q Nd：YAG激光器的理论研究

本文主要从理论上分析了ＤＰＬ调Ｑ激光器的动态特性，并对电光调Ｑ与声光调Ｑ激光器的输出特性进行了比较．     

窄发散角量子阱激光器的结构设计与分析

本文对ＧａＡｓ／ＡｌＧａＡｓ量子阱结构激光器中重要的结构参数与远场垂直发散角的关系作了系统的理论计算与分析，提出了实现２０°～３０°垂直发散角的有效途径，并同时研究了对激光器的光功率限制因子、阈值电流密度等重要参数的影响．     

一种外场环境中舰载光电跟踪仪光轴一致性检测方法

光轴一致性是影响舰载光电跟踪仪跟踪精度的一项重要技术指标。本文提出一种外场环境中光轴一致性的检测方法,详细介绍了该方法的检测操作步骤,分析了检测精度,并在外场环境中进行了实际检测。该方法使用工具少,操作简便,而且能够满足检测精度要求,适合靶场使用。     

凹面反射镜焦面的精确标定和提高激光产品光轴平行性的方法

本文阐述了反射镜焦距、焦面标定误差、激光产品跨距和光轴平行性的关系,提出了一种标定焦面位置较精确的方法。     

一种圆筒形气体激光器的谐振腔方案

提出了一种光谱适用性较广、大功率输出的新型圆筒形增益区气体激光器的谐振腔设计方案.此腔由两个反射镜和含于两反射镜之间的两透镜组成,这种谐振腔方案更适宜于在5.3μm波长具有很高透过率材料(如CaF_2)的CO激光器和在可见光波段具有很高透过率材料(如光学玻璃)的He-Ne激光器.同时,结合实际应用以CO激光器为例,给出了其光腔参数.     

一种密闭式高压电源的结构设计

过去雷达发射机中的高压电源，其油箱大多采用开式结构，其优点是便于维修，但绝缘油的渗漏却成了一个很难解决的问题，另外，为了解决油的体积膨胀问题，这种电源往往采用副油箱，体积较大。本文讨论的密闭式高压电源很好地解决了上述问题。     

Optimal design improving a communication network reliability

Improvement of the reliability of a communication network is an optimal problem that finds some links to add to the network such that the reliability of the network reaches a given level and the total cost of these links is minimized. A decomposition method based on branch and bound is used for solving the problem. In order to speed up the solution procedure, an upper bound on system reliability in terms of node degrees is applied. Specially, when the threshold P_o is large enough, a new algorithm, the cut tree algorithm, can more effectively give the optimal solution.     

一种腔体滤波器悬臂螺旋振子的抗冲振优化设计

针对大功率腔体滤波器螺旋振子刚度小,在载机环境条件下特性响应曲线不稳定的问题,提出了一种螺旋振子的抗冲振创新设计思路与方法.通过铝材铣制成梯形截面螺旋振子增加其刚度,采用对称局部环抱的异形结构件对悬臂螺旋振子进行加固以提高抗冲振能力.优化设计后的振子顺利通过载机环境试验考核和电性能指标测试.该设计方案已成功应用于大功率跳频滤波器设备中,效果良好.     

Optimal design of PML absorbing boundary condition for improving wide-angle reflection performance

A method to optimise the angle reflection performance of Berenger's perfectly matched layer (PML) absorbing boundary condition for finite-difference time-domain (FDTD) method is described. By specifying the conductivity in each of the PML sublayers, the wide-angle reflection performance can be improved. To improve the angle reflection performance as well as to reduce the discretisation error characteristic due to the FDTD approximation, a two-step conductivity profile is used in PML. To obtain the optimal value for each conductivity profile, the micro-genetic algorithm method is employed. Using this method, good wide-angle reflection performance of PML is achieved.     

具有振动免疫特性光学谐振腔设计方法研究

窄线宽稳频激光是研制光学原子钟、引力波探测、 光学频率合成器以及低噪声微波源等研究的核心部分,由振动噪声引起的频率噪声已成为实 现具有更窄线宽、更高频率稳定度 激光的主要限制性因素。本文利用Ansys有限元分析的方法,通过优化参考腔的切割深度和 支撑位置以及ULE环的尺寸,使得腔镜在振动作用下保持平行同时腔镜各点均具有较低的振 动敏感度,避免了由于装配误差引起腔长变化的问题。在对光学参考腔几何尺寸优化设计后,对光学谐振腔不同频率处的振动敏感度进行测试及分析,结果表明在最佳支撑位置下空间三轴方向的振动敏感度均可被抑制至 10－10 g－1量级,实验结果和仿真结果相吻合。此方法为振动免 疫结构腔体的设计提供了一种思路,也为进一步实现具有更高频率稳定度、更窄线宽激光奠 定了基础。     

Technique for improving coupling between microstripline anddielectric resonator antenna

A cylindrical dielectric resonator antenna fed by a microstripline is studied. By connecting a vertical strip at the end of the microstripline, the input matching of a dielectric resonator antenna can be improved substantially. Moreover, it offers an impedance bandwidth as wide as 19% and a stable radiation pattern across the operating frequency range     

Optimal design of IIR digital filters with robust stability using conic-quadratic-programming updates

In this paper, minimax design of infinite-impulse-response (IIR) filters with prescribed stability margin is formulated as a conic quadratic programming (CQP) problem. CQP is known as a class of well-structured convex programming problems for which efficient interior-point solvers are available. By considering factorized denominators, the proposed formulation incorporates a set of linear constraints that are sufficient and near necessary for the IIR filter to have a prescribed stability margin. A second-order cone condition on the magnitude of each update that ensures the validity of a key linear approximation used in the design is also included in the formulation and eliminates a line-search step. Collectively, these features lead to improved designs relative to several established methods. The paper then moves on to extend the proposed design methodology to quadrantally symmetric two-dimensional (2-D) digital filters. Simulation results for both one-dimensional (1-D) and 2-D cases are presented to illustrate the new design algorithms and demonstrate their performance in comparison with several existing methods.     

Noise design of active feedback resonator BEF

It is shown that, in a filter design system which introduces noise temperature into the active feedback resonator (AFR), the AFR band elimination filter (BEF) can be designed using techniques for the conventional passive BEF. In this system, the passive BEF circuit used for electrical design is also useful for the noise analysis of the AFR BEF. This analysis reveals that the noise figure (NF) value of the AFR BEF can be calculated from the noise temperatures of AFRs. The optimum NF value is obtained by minimizing these noise temperatures. The noise design of a three-pole AFR BEF is discussed. It is found that the observed NF of the three-pole AFR BEF agrees well with the theoretical values deduced from the designed S-parameters and the observed noise temperatures of the AFRs     

Stable-unstable resonator design for a wide-tuning-rangefree-electron laser

A stable-unstable resonator design which employs a one-sided negative-branch unstable mode in the plane perpendicular to the wiggler magnetic field and a stable Gaussian cavity mode in the perpendicular direction can provide a near-ideal solution for a very-wide-tuning-range infrared free-electron laser. A trial design which provides for all-reflective optics, reasonable output coupling, and potentially continuous tunability from 3 to 50 μm in a single resonator is described     

Temperature stability of a piezoresistive MEMS resonator including self-heating

Temperature stability of a piezoresistive 1.5 μm thin SOI resonator at 74 MHz is presented. As compared to capacitive resonators the self-heating due to the bias current causes a further decrease of the resonator frequency, in addition to the well-known dependency on ambient temperature. The interpretation of the resonance frequency as a device temperature is not obvious anymore under self-heating due to the inhomogeneous temperature distribution.     

Methods for improving the stability of electromagnetic geophysicalinversions

Two methods are presented for improving the stability of geophysical inversions. The first method uses the weighted-least-squares technique to reduce the effects of additive noise in the measurement data. This is accomplished by giving a lesser weight to those measurements that are thought to be more noisy. Some simulations are presented that demonstrate the effectiveness of this method. In addition, the authors explore the possibility of using postreconstruction image processing to reduce the effects of noise in the measurements. A novel technique, referred to as minimax partitioning, is developed. This method, in conjunction with image filtering is used to locate high-contrast anomalies in a region. Examples are presented that show the superiority of this partitioning scheme over other techniques