A Least-squares Window Curves Method for Interpretation of Magnetic Anomalies Caused by Dipping Dikes

We have developed a least-squares method to determine simultaneously the depth and the width of a buried thick dipping dike from residualized magnetic data using filters of successive window lengths. The method involves using a relationship between the depth and the half-width of the source and a combination of windowed observations. The relationship represents a family of curves (window curves). For a fixed window length, the depth is determined for each half-width value by solving one nonlinear equation of the form f (z) = 0 using the least-squares method. The computed depths are plotted against the width values representing a continuous curve. The solution for the depth and the width of the buried dike is read at the common intersection of the window curves. The method involves using a dike model convolved with the same moving average filter as applied to the observed data. As a result, this method can be applied to residuals as well as to measured magnetic data. Procedures are also formulated to estimate the amplitude coefficient and the index parameter. The method is applied to theoretical data with and without random errors. The validity of the method is tested on airborne magnetic data from Canada and on a vertical component magnetic anomaly from Turkey. In all cases examined, the model parameters obtained are in good agreement with the actual ones and with those given in the published literature.     

水深测量数据处理中的粗差探测技术

从目前出现在水深数据处理中最有可能存在的 :一条测深线上孤立零点的粗差、一条测深线上具有连续性的粗差以及相邻测线上具有连续性和相关性的粗差等三种情况 ,分别提出剔除这些粗差的方法 ,通过实例分析可以得出本文所提出的粗差剔除方法是有效的 ,在实际测量中具有一定的实用性     

高压旋喷技术在基坑护壁与止水工程中的应用

长沙天都大厦工程围护墙先后采用2套方案施工,实践证明,采用高压旋喷单管双液分喷法具有设备简单;投资少;操作容易,施工速度快;桩间搭接严密,固结体强度高;适用范围广等优点,尤其在处理软弱地基、基坑支护和止水工程中显示出有效性、可靠性和优越性。该方法再经进一步完善,将具广阔的推广前景。     

一种层析成像的正演和反演方法

作者在本文中提出了一种层析成像的正演和反演方法，首先对求解区作网络划分，由给定的正演速度模型在网格点上双线性插值，获得整个网格节点的速度分布，然后，对波阵面作一近似，在此基础上，用最小走时最短路径射线追踪法完成正演，反演则是通过正演的方法实现的，理论模型算例表明，本方法效果较好。     

511铀矿床区域水文地质综合评价中的同位素技术研究

本文在资料调研的基础上，探讨了地下水埋深的影响因素，介绍了应用同位素水文技术，水化学和水中微量元素分析及同位素单孔示踪技术等综合评价方法研究地下水成因及运移的控制因素，查明511铀矿地浸采矿中的水文地质问题。     

钻井成井中机械洗井方法的适用条件与效果

根据多年来从事水文地质钻井成并工作的经验，结合具体工程实例，对活塞、空压机、泥浆泵、清水泵，接力泵等洗井方法的性能和应用条件作了一些总结，但对于井管直径较大或井水较深的管井，采用联合洗井方法往往可以扬长补短，改善单种洗井方法效果不理想的状况，并取得洗井的最佳效果。     

Laser-based validation of GLONASS orbits by short-arc technique

 The International GLONASS Experiment (IGEX-98) was carried out between 19 October 1998 and 19 April 1999. Among several objectives was the precise orbit determination of GPS and GLONASS satellites and its validation by laser ranging observations. Local laser-based orbit corrections (radial, tangential and normal components in a rotating orbital local reference frame) are computed using a geometrical short-arc technique. The order of magnitude of these corrections is at the level of few decimeters, depending on the considered components. The orbit corrections are analyzed as a function of several parameters (date, orbital plane, geographical area). The mean corrections are at the level of several centimeters. However, when averaging over the entire campaign and for all the satellites, no mean radial, tangential and normal orbit corrections are found. The origin of the observed corrections is considered (errors due to the geocentric gravitational constant, the non-gravitational forces, the thermal equilibrium of on-board equipment, the reference systems, the location and the signature of the retroreflector array, and the precision of the satellite laser ranges). Some features are also due to errors in the radio-tracking GLONASS orbits. Further investigations will be needed to better understand the origin of various biases. Received: 17 February 2000 / Accepted: 31 January 2001     

我国期气候预测的业务技术发展

概述了我国短期气候预测技术和业务现代化发展的历史，分析了“九五”以来我国短期气候预测技术的新进展，探讨了未来短期气候预测技术发展的几个主要问题。     

Forecasting Monsoon Precipitation Using Artificial Neural Networks

This paper explores the application of Artificial Intelligent (AI) techniques for climate forecast. It pres ents a study on modelling the monsoon precipitation forecast by means of Artificial Neural Networks (ANNs). Using the historical data of the total amount of summer rainfall over the Delta Area of Yangtze River in China, three ANNs models have been developed to forecast the monsoon precipitation in the corre sponding area one year, five-year, and ten-year forward respectively. Performances of the models have been validated using a ＇new＇ data set that has not been exposed to the models during the processes of model development and test. The experiment results are promising, indicating that the proposed ANNs models have good quality in terms of the accuracy, stability and generalisation ability.     

磁通门磁变仪与经典磁变仪状态函数之比较

分析了影响磁通门磁变仪定向状态函数和经典磁变仪定向状态函数改变的因素，对磁通门磁变仪定向状态函数和经典磁变仪定向状态函数及其稳定性进行了比较，得出了有益的结论。