飞秒光谱全息技术及飞秒整形技术的应用

飞秒光谱全息是飞秒脉冲整形技术中非常重要的一种方法,它可以实现飞秒脉冲信号的记录、再现和处理。主要介绍飞秒光谱全息技术及飞秒脉冲时空变换整形在飞秒化学领域的最新应用。     

激光束空间整形的研究现状

阐述了对激光器输出光束进行空间整形的必要性,介绍了目前常用的一些典型的光束整形方法和器件,并分析了各种方法的优点和缺点.     

一种改进的阵列天线方向图主波束快速赋形算法

改进的基于自适应天线阵理论的主波束赋形快速算法,可对任意阵列快速完成主波束赋形和旁瓣电平的控制.该算法通过局域权函数的迭代来减小综合方向图和期望方向图在主波束上的差别,旁瓣电平的控制可以通过在旁瓣峰值区域处加干扰来快速达到.该方法对主波束方向、宽度、形状和增益的控制非常成功.给出了一些算例说明这种算法的有效性.     

Control of an overlap-type proportional directional control valve using input shaping filter

In a hydraulic control system (herein, termed a major control loop), a proportional directional control (PDC) valve with spool position feedback may work in a minor (or inner) control loop. In this study the authors propose control designs to improve the performance of the PDC valve control loop (a minor control loop). At first, the mathematical model for the PDC valve is developed through an experimental identification process. Then, a dead-zone compensator that facilitates jumping of the overlap zone in spool/sleeve combination is devised and applied. A reference input following controller (including PI-D and feed-forward controller) that enables robust control of the PDC valve under disturbances is devised using the pole placement method and the zero placement method. Subsequently, an input shaping filter is incorporated into the devised control system to improve the reference following characteristic in high frequency range. Finally, the effectiveness of the proposed control design is verified experimentally.     

Spherical distribution structure of the semiconductor laser diode stack for pumping

A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution.     

利用集成光学调制器实现ICF固体激光驱动器中激光脉冲任意整形 Ⅱ.集成光学调制器

本文利用集成光学和光纤技术制作了集成光学调制器,驱动调制器的电压仅为４伏,配之以高稳定的、ＬＤ泵浦的单纵模振荡源和任意整形电脉冲源,大大提高了ＩＣＦ固体激光驱动器前级整形系统对激光脉冲整形的稳定性和灵活性．     

雷达信号成形规律的样本体系描述方法

针对多功能雷达工作在搜索方式时,其工作模式的转换以及同一模式下的脉冲信号均有规律可循的工作特点,提出一种基于雷达信号成形规律的样本体系描述技术。该方法利用多功能雷达工作模式的转换规律和脉冲本身的时频域参数变化规律,建立搜索模式转换样本、脉冲样本图和样本脉冲的层级数学模型,对多功能雷达脉冲信号成形规律进行提取和准确描述。仿真实验表明,样本体系描述技术不仅能够提取其对应的复杂体制雷达工作模式和脉冲信号,而且对噪声环境具有较好的适应能力。     

“非零”传动弧齿锥齿轮CAD系统的开发与研究

讨论了锥齿轮CAD开发的办法与原则,介绍介在AutoCAD2000平台上,用objectARX2000开发工具开发的“非零”传动螺旋锥齿轮CAD系统。利用面向对象技术开发的这一系统,借助于优化设计,在螺旋锥齿轮工程数据库支持下,可帮助设计人员快速完成螺旋锥齿轮的设计、校核、出图和加工前的准备工作。大大缩短了设计加工周期,提高了生产率。     

永磁铁氧体径向性能与压制成型的研究

介绍了几种常用的提高永磁铁氧体径向性能的压制成型方式 ,阐述了压坯密度及其分布、取向场、收缩率对产品性能和出现层裂及尺寸不合格等现象的影响及其相互关系 ,并提出了相应的解决办法。针对不同产品类型介绍了模具设计的工艺原理及成型方式     

长轴斜齿轮的加工

以无差动滚切法为基础 ,提出了利用花键轴铣床加工长轴斜齿轮的方法 ,为花键轴铣床扩展了加工功能。