High Power Fiber Bundle Array Coupled LDA Module

1 Introduction High power laser diode arrays (LDA) have many advan- tages such as small volume, long working life, high slope efficiency and high optical density, so they have many applications in medical treatment, material pro- cessing, and for the pumping source of solid laser and etc. But unfortunately, the LDA can not be easy to use directly in these fields because of their poor beam quality and extremely asymmetric divergent beams (!x≈ 5°～10°and !y≈20°～35°, for example), so it …     

Development of Fiber Lasers and Their Applications

1 Introduction Fiber lasers have been developed for more than forty years since Snitzer!s proposal and the demonstration of Nd- doped fiber in 1961 [1]. But fiber lasers have not been attracted considerable attention until the develop- ment of the low- loss fiber fabrication technology and the high power semiconductor laser technology recently. Actually,it is the application and development of fiber communication technology that has promoted the rapid development of fiber laser. Fiber laser, …     

激光远场直接探测系统探测器阵列靶板的设计

设计了一种激光远场直接探测系统,对系统中的两个关键问题进行了讨论,一、在探测 器阵列靶板尺寸的确定问题上讨论了激光的衍射效应和大气湍流的影响;二、在探测器阵列靶板分辨率的确定问题上讨论了激光的衍射效应和大气湍流的影响;对第二问题讨论了对其有影响的三个方面:大气湍流引起激光碎斑尺寸,由采样定理决定的空间采样率,由阵列探测器的频谱函数引起的损失。这些影响都是在设计时必须予以充分考虑的因素。     

WSN中一种最优的汇聚节点移动方案

研究了无线传感器网络中,如何在不同的候选位置放置数据汇聚节点来最大化网络生命周期。通过定义＂放置模式＂这一概念,对数据流通模式进行分类,从而从量级上降低了需要调度的因素的数目。基于这样的理念,对问题建立了线性优化模型,来构建一种最佳的放置策略。最后,通过具体的试验验证了提出方法的有效性,说明了即使使用一个移动位置受限的汇聚节点,也会极大地提升网络生命周期。     

成像制导武器干扰效果评估方法研究

分析了成像制导武器干扰效果等级的划分依据.计算了干扰前与干扰后成像制导武器的杀伤概率变化及干扰成功率,提出了一种对成像制导武器的干扰效果评估准则,可用于评价对成像制导武器的干扰效果.     

通孔氧化铝模板的制备和光学特性

采用阳极氧化法,制备了二维有序纳米通孔氧化铝模板.研究了工艺参数对通孔有序性、孔径、模板厚度等的影响,测量了通孔氧化铝模板的光透过、光吸收和光发射等光学特性.结果表明,在波长360 nm附近通孔氧化铝模板的光透过谱线和光吸收谱线发生突变,波长大于360 nm时,光透过增强;波长小于360 nm时,光吸收增强.通孔氧化铝模板的光致发光强度和峰位与激发光波长有关,光致发光谱范围在340～600 nm.     

A Novel Sparse Penalty for Singular Value Decomposition

Singular value decomposition (SVD) is a tool widely used in data denoising, matrix approximation, recommendation system, text mining and computer vision. A m a jority of applications prefer sparse singular vectors to capture inherent structures and patterns of the input data so that the results are interpretable. We present a novel penalty for SVD to achieve sparsity. Comparing with the traditional penalties, the proposed penalty is scale, dimen-sional insensitive and bounded between 0 and 1, which are in favor of controlling sparsity. Regulated by the penalty, we provide an efficient algorithm to pro ject a vector onto a given sparse level in O(n) expected time. The efficient pro jection algorithm serve as a drudge for sparse SVD (SSVD). In experiments, SSVD is efficient and could cap-ture the latent structures and patterns of the input data.     

基于HFSS的微调谐腔体带通滤波器设计

针对微调谐腔体带通滤波器设计制造中存在的问题,介绍了腔体带通滤波器的总体设计;论述了需要解决的问题,如优化计算、提高仿真精度和简化调谐结构,并对二端口网络等效替换、整体仿真和微调谐关键技术进行了分析;最后阐述了仿真与性能测试结果分析,测试结果分析说明微调谐腔体带通滤波器设计精确且拥有很好的应用前景。     

基于环流反馈的逆变器并联系统仿真分析

对于逆变器并联系统,各模块输出电压之间如若存在幅度和相位上的差异,势必会产生在模块间流动的环流。文中在逆变器并联系统环流产生机理分析的基础上,对是否加入环流反馈时系统的阻抗和稳定性进行了分析,证明采用环流反馈可以增大系统环流阻抗,在保持输出电压不变的前提下有效地减小了环流,最后通过Simulink仿真证明此方式的有效性。     

IEEE 802.16e睡眠模式的自适应算法

IEEE 802.16e标准中使用了睡眠模式以达到降低移动台的功率消耗和基站接口资源的使用.本文将使用马尔可夫模型对IEEE 802.16e睡眠模式的功率消耗和时延进行分析.通过分析得知在功率消耗和时延之间有一个权衡,其中的关键因素就是初始的睡眠周期.为此提出一个根据传输速率调整初始睡眠周期大小的自适应算法.仿真结果表明与802.16e标准相比自适应算法能节约20%的功率,仅仅损失了一点时延.