射频电缆的幅相稳定性测试研究

对射频电缆幅相稳定性进行了介绍,阐述了射频测试电缆相位和幅度变化的因素,并详细分析了射频电缆相位性能以及幅度性能的不同测试方法,最后通过实测数据的展示,总结说明了在日常测试中该如何正确使用测试电缆。     

基于三相幅度测量的相控阵天线快速校准方法

提出了一种基于三相幅度测量的相控阵天线快速校准方法。该方法将天线阵列进行分组,利用每种分组在三种配相下的阵面合成场幅度测量值,可解算出各个天线单元的初始幅相值。该方法仅需幅度测量,避免了相位测量误差影响单元幅相值的计算精度,而且所需幅度测量次数仅为(2N+1)次,可显著提高校准时效性。另外,利用分组思想,同时改变多个单元相位,使总辐射场的幅度变化显著,提升校准准确性。仿真结果表明:校准后相位均方根误差为2.2°,幅度均方根误差为0.2 dB。     

Optimal Planar Interception with Fixed End Conditions: Approximate Solutions

In a previous paper (Ref. 1), an exact solution of the optimal planar interception with fixed end conditions was derived in closed form. The optimal control was expressed as an explicit function of the state variables and two fixed parameters, obtained by solving a set of nonlinear algebraic equations involving elliptic integrals. In order to facilitate the optimal control implementation, the present paper derives a highly accurate simplified solution assuming that the ratio of the pursuer turning radius to the initial range is small. An asymptotic expansion further reduces the computational workload. Construction of a near-optimal open-loop control, based on the approximations, completes the present paper.     

Well-Posedness by Perturbations of Variational Problems

In this paper, we consider the extension of the notion of well-posedness by perturbations, introduced by Zolezzi for optimization problems, to other related variational problems like inclusion problems and fixed-point problems. Then, we study the conditions under which there is equivalence of the well-posedness in the above sense between different problems. Relations with the so-called diagonal well-posedness are also given. Finally, an application to staircase iteration methods is presented.     

一类含参广义集值拟变分包含组的解的灵敏性分析

本文引入了一类新的含参广义集值拟变分包含组,应用隐预解算子技巧,建立了该类变分包含组与一类不动点问题的等价性,在适当的条件下,分析了含参广义集值拟变分包含组的解的灵敏性,所得结果推广改进了最新文献中的许多结果．     

On the duration of the total eclipse of a satellite of a body

This paper solves the problem of the duration of the total eclipseof a satellite of a body, provided that (a) the body is sphericalin shape and the mass distribution inside the body is sphericallysymmetrical; (b) the satellite is a very small object; (c) thesatellite's orbit around a body is circular and the satellitecan pass through the centre of its shadow; (d) a source of lightis the source of the conical body's shadow (umbra) and it doesnot change its apparent position in the sky; (e) there are noperturbations on the satellite's orbit. The solution presentedrepresents the general discussion of the problem based on utilizationof some parts of the theory of contraction mappings.     

系数变号的半线性椭圆方程的正解

本文研究半线性椭圆方程Dirichlet问题-△u=α（x）f(u），x∈Ω， u（x）=0，x∈ЭΩ，正解的存在性，其中Ω为R^n中有界的带光滑边界的区域，α(x)可以变号。     

利用振幅调制器进行光电负反馈抑制激光强度噪声

采用振幅调制器作为抑制激光强度噪声的元件，首先对光电负反馈回路进行了简要的理论分析，然后利用该光电负反馈进行抑制激光二极管抽运全固化单频环形Nd:YVO4红外激光器强度噪声的实验。结果表明，在0－1MHz的低频段，强度噪声大幅度降低，最大降低约15dB。     

用能量法求多自由度振动系统的角频率

利用简谐振动能量方程，通过分析振幅矢量的关系，用能量法求多自由度振动系统的角频率或简正振动频率。