高速飞行器的电磁散射增强现象研究

对空间飞行器的电磁波散射截面进行了计算。本文取八种入射频率、五个高度上的电子密度所对应的电磁波散射截面和电声波散射截面进行了计算。结果表明,在正常情况下散射增强范围比Chen在辐射研究中给出的范围要大些。本文还对超高频波段在一些特定区产生的散射增强,用电离层中某些尺寸的不均匀结构的影响给予初步解释。     

用交流电阻率法探测煤矿导(含)水构造

分析了煤矿井下地球物理场的特殊性,指出电阻率法的频率域测量方法具有压制工业干扰能力强、克服电极接地条件差的优点,适用于煤矿井下作业环境的需求。煤矿井下实际探测结果说明,交流电阻率法在三维空间内异常定位准确,适用于煤层是否存有导(含)水构造的采前探测。     

油气悬挂技术及其在车装钻机中的应用展望

油气悬挂系统具有优越的非线性弹性特性和良好的减振性能，能大幅度改善悬挂系统的性能。介绍了油气悬挂技术在车装钻机的应用现状，指出了油气悬挂系统的引入对车装钻机等特种工程车辆发展的重要性。     

城市规划区中的转角直线定线方法

本文介绍如何解决城市规划区域内转角无法定立或转角前后互不通视地段的定线工作，该方法是在间接定线方法基础上采用解析法计算出直线桩及转角桩的放样元素来解决定线工作。提高了平断面图的施测精度，满足了规划部门的要求，取到了较好的经济效益，大大地加快了线路的定线工作。     

电子政务中的人口空间管理和分析

介绍了在国家级人口地理信息系统中 ,利用 2 0 0 0年人口普查信息 ,采用三维模型显示、罗伦斯曲线、人口重心和人口潜力等方法 ,宏观分析了中国人口分布的特征。并在城市人口地理信息系统的基础上 ,通过对城市零售单位布局的分析 ,介绍了人口地理信息系统的微观分析和应用过程     

判断观测值粗差能否发现和定位的一种验前方法

由于最小二乘(LS)残差统计相关，使得粗差发现和定位关系变得相当复杂，且至今未见有效的理论和方法。作者依据在LS平差前进行粗差发现和定位的思路，有意避开LS残差统计相关的难题，从条件平差模型推导出粗差判断方程(GEJE)Vr＝JVt Wc建立起以上式判断矩阵J为基础的粗差发现和定位的判断准则：1．不能发现含有粗差的观测量；2．能发现含有粗差但不能定位粗差的观测量。通过算例的检验，证明了判断矩阵J与控制网中观测量数据结构的对应关系，同时说明粗差不能定位的观测量，再好的粗差检测方法也无法正确定位粗差。     

Optimal location of sensors for reconstruction of seismic responses through spline function interpolation

In this paper, a criterion is proposed for the choice of the optimal location of a limited number of recording sensors for reconstruction of seismic responses of multistorey frames. Reconstruction of unknown responses is performed by modelling through a spline shape function the evolution of the relative acceleration along the height of the building. The coefficients of the spline function are determined by interpolating available responses in terms of absolute accelerations taking into account boundary conditions. The optimal location for a given number of recording sensors is defined as the one corresponding to the minimum value of the global error evaluated on the whole set of reconstructed responses. The criterion has been verified by using simulated responses of numerical models of multistorey frames and responses recorded on real buildings during the Northridge earthquake. A physical characterization of the location of available sensors leading to the minimum global error between calculated and real responses is proposed in terms of effective modal participation factors relevant to the principal modes of the structure. This characterization allows for frames of known modal characteristics the definition of a criterion for the choice of the location of a limited number of sensors for monitoring or vibration control purposes. Copyright © 2003 John Wiley & Sons, Ltd.     

测震学信息增益合成方法及其在地震预报中的应用

提出了一种地震预报的新方法，并应用于地震的地点预测。震例的空间扫描异常区的对比表明，该方法比单项地震预报方法圈出的异常区不仅范围小，而且包围或接近震中。     

Multiplet relative location approach and waveform correlation correction and their application

Introduction When the distribution of a cluster of earthquakes is concentrated, distance between hypocen-ters is much smaller than the event-station distance and than the scale length of the velocity het-erogeneity in the hypocenter region; in this case, the ray path from each hypocenter to a common station will be almost the same. The relative location method can be applied to accurate location of the cluster in the above case. In this approach, the relative location is calculated with the ar…