宽带被动导引头天线系统性能分析

详细讨论了宽带被动导引头中的关键部件－超宽频带天线的性能，并在此基础上分析了三种具备大视角特性的被动测角方法。由于宽带天线没有确定的相位中心，因此不能采用通常的振幅和差式单脉冲法进行宽频带测角。本文提出的波束运算网络可用于一个宽带螺旋天线同时得到两个交叉波束的振幅－振幅式单脉冲系统中。此外，对比幅相干测向法中的测角模糊问题也进行了研究。     

MODE SPACE SMOOTHING ALGORITHM TO ESTIMATE DOA OF COHERENT SIGNALS IMPINGING ON UNIFORM CIRCULAR ARRAY

A novel method to estimate DOA of coherent signals impinging on a uniform circular array( UCA) is presented in this paper. A virtual uniform linear array (VULA) is first derived by using spatial DFT technique, transforming the UCA from element space to phase mode space to obtain the properties of ordinary ULA, and then the well known spatial smoothing technique is applied to the VULA so that the lost rank of covariance matrix due to signal coherence can be retrieved. This method makes it feasible to use the simple MUSIC algorithm to estimate DOA of coherent signals impinging on a UCA without heavy computation burden. Simulation results strongly verify the effectiveness of the algorithm.     

电视加解扰系统原理与诸方案

随着改革开放的深入发展，人们对电视的要求也越来越高，原有的电视节目已难以满足人们的需要。加解扰收费电视即应运而生。本文介绍的几种加解扰电视方案只是众多加解扰系统中的一斑，反映了电视加解扰的发展过程。     

新疆引额济克西干渠隧洞工程地质

新疆引额济克西干渠工程在软弱地质体的围岩中成功的进行了总长 8.9km,洞径 5 m× 5 m,5条隧洞的勘测、设计、施工 ,并进行了大塌方 ,冒顶的工程处理 ,在新疆的水利水电工程建设中尚属首次 ,在全国也不多见 ,积累了成功的经验 ,在此提出 ,供同行参考。     

以矿石质量控制为目标的卡车调度系统控制理论模型

本文应用最优控制的理论建立了以矿石质量控制为目标的卡车调度系统的数学模型。并求出了某实例的数值解,对解的分析说明控制理论模型比以往的方法有本质的进步。     

一种适于大型水轮发电机磁场计算前处理的新方法

本文在采用微分法生成四边形网格的基础上,实现了大型水轮发电机有限元计算用的三角单元自动生成。在前处理技术中,提出了采用电机定子线圈轮换数进行源区加电流的新方法。     

电弧炉的微机控制

本文通过分析采用了恒电流充方式作为电弧炉电极升降控制方式,给出了电弧炉单片机控制系统的原理框图,以及采用模块化设计方法实现的部分软件框图。     

Transport Properties of the Mixed-Conducting SrFe1.2Co0.3Ox

Single phase SrFe_1.2Co_0.3O_x sample with layered crystal structure was prepared using a solid state reaction method. Electrical conductivity and apparent oxygen diffusion coefficients of the SrFe_1.2Co_0.3O_x sample were measured as functions of temperature in atmospheres of various oxygen partial pressures . Total and ionic conductivities were determined by using the conventional four-probe and electron blocking four-probe methods, respectively. The apparent oxygen diffusion coefficient was derived from the time-dependent conductivity relaxation data of the reequilibrium process after abruptly changing the in the surrounding atmosphere. Several atmospheres of different were established by the use of premixed gas cylinders. The conductivity of SrFe_1.2Co_0.3O_x increases with increasing temperature and . At 900°C in air, the total conductivity and ionic conductivity are 10 and 8S · cm^-2, respectively. The ionic transference number ( 0.8 in air) does not have strong temperature dependence. The activation energy increases with decreasing . In air, the activation energy has a low value of 0.37 eV. The apparent oxygen diffusion coefficient was at 950°C over a wide range of .     

Study of influence of buried metallic structures on soilresistivity measurements

A detailed study of the influence of buried metallic structures on soil resistivity measurements has been carried out. Different measurement methods, various soil structures, and different locations of measurement profiles with respect to metallic structures have been analyzed. It is found that the influence of buried metallic structures on soil resistivity measurements can be significant and that this influence varies in a wide range depending on measurement methods, locations of measurement profiles and soil structure characteristics. This study also shows how to choose measurement locations to minimize the influence of buried metallic structures when soil resistivity measurements must be made in the presence of buried metallic structures     

矿用电机车直接力矩控制系统

介绍了一种新型工矿电机车直接力矩控制的交流异步电动机驱动系统的基本原理,分析了这种驱动系统的特殊要求,提出了采用无速度传感器实现力矩控制的设计思想,并应用DSPTMS320C30和IGBT开关器件组成了全数字化的控制系统.理论分析和实验结果证明,这种系统具有优良的静态和动态特性.