运用改进系统建模法对南海气象数据的建模研究

在系统建模理论的基础上,运用改进的动态数据建模方法,对南海气象数据中的温度进行建模并验证了模型的适用性.根据模型推导出格林函数、逆函数和自协方差函数等,并讨论了南海气象数据中温度模型的稳定性、可逆性和合理性.对系统的频率特性和谱函数进行分析讨论,并给出建模过程中的一些图像.根据模型的适用性检验发现,对所研究的气象数据而言,ARMA(4, 3)模型是最合适的,具有平稳可逆性.所有的建模和分析过程在MATLAB上实现.实验结果表明这种建模方案简便易行,能够快速准确地确定系统的合理模型.     

基于GIS的孔隙水文地质层三维空间离散方法

针对自然界中孔隙水文地质层空间分布的不连续性与厚度分布的不均匀性,研究基于GIS的孔隙水文地质层三维空间离散实现的技术路线,提出基于GIS的孔隙水文地质层不规则六面体元的三维空间离散方法.该法不仅能最大限度地保证不规则六面体元中水文地质层类型的一元性,而且可充分利用GIS的空间分析与数据的自动提取功能,快速提取各个计算结点上空间位置坐标与各类计算参数,大大缩短水文地质模型空间离散与相关数据文件组织所需的时间,提高地下水三维有限差分数值模拟的时效性,具有较高的实用价值.     

国外国土开发整治与规划的经验及启示

本文简要回顾了20世纪以来国外国土开发整治与规划的过程，总结了国外在国土规划方面取得的经验：即国土规划的权威性、系统性、针对性、可操作性、实效性和参与性等特点。在此基础上，结合我国国情，针对当前面临的形势，提出发展和完善我国国土规划的基本思路：重视国土规划；将国土规划纳入规范化、法制化的轨道；强化国土规划的系统调控和管理等。     

GPS广播星历参数拟合算法

介绍了GPS广播星历参数的最小二乘估计方法。推导了相应的计算公式。计算结果表明。文中给出的公式是正确的，其拟合精度以用户距离误差(URE)示时，对预报轨道的损失小于1cm。     

A 3D BEM-FEM methodology for simulation of high speed train induced vibrations

This work presents an efficient methodology for the analysis of vibrations in a railroad track system, induced by the passage of conventional and high-speed trains. To this end the Boundary Element Method is used to model the soil-tie system within the framework of impulse response techniques. Conventional Finite Element Methods along with Newmark's integration is used for the modeling of the rail system. The two methods are coupled at the tie-rail interface and the solution is obtained following a staggered, time marching scheme in an efficient manner. The methodology accounts for Soil-Structure Interaction and traveling wave effects. In addition, this work identifies the parameters that affect the efficient modeling of railroad track systems as they pertain to the proposed solution methodology.     

工程勘察设计信息集成化系统的实施状况及其思考

国家建设部“全国工程勘察设计行业2000～2005年计算机应用工程及信息化发展规划纲要”发布后,备受工程设计企业关注,但推行情况却不甚理想。本文通过阐述信息集成化系统的主要任务和目标,分析其应用状况,寻求推广受阻原因,提出了开发该系统的思路和改善其实施环境的建议。     

沉降-时间曲线呈“S”型的证明及其应用——从土体本构关系

从土体本构关系出发,严格证明了在线性加载或近似线性加载情况下(这和岩土工程实际加载相类似),沉降-时间曲线呈“S”型,并由此建立了新的沉降-时间预测模型,工程应用证明了该模型的合理性。     

Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China

Nongla, a typical karst dynamic system (KDS) monitoring site, is located at Nongla Village, Mashan County, Guangxi, China. The data from a Greenspan CTDP300 multichannel data logger indicates that the KDS is highly sensitive to environmental changes. Multi-day and diurnal physico-chemical composition of epikarst spring water is quite different under different climatic conditions. During a day with no rainfall, water temperature and air temperature have similar variations. Electrical conductivity (EC) has good positive correlation with pH value and water temperature. During rainstorms, the physico-chemical composition of the spring water is initially strongly effected by dilution, pH and EC drop rapidly. However, half to one hour later, EC returns to normal and the CO₂ effects will be the dominant physical effect. This is due to the high fissure rates and high permeability in the epikarst zone. Dilution effects were observed during the entire rainstorm event,whereas, it only acts during the earliest period of light rain. Therefore, it is necessary to examine the water–rock–CO₂ combination as a whole system to explain the hydrochemical behavior of epikarst processes.     

论华夏成矿省——贺陈毓川院士九十华诞

笔者等对《中国矿产地质志·华南洋—滨太平洋构造演化与成矿》一书（2020）厘定的战略矿产资源居于重要地位的华夏成矿省作些简要论述：① 该成矿省处于古华南洋成矿域与滨太平洋成矿域强烈复合地带,历经早前寒武世克拉通—华南洋—华南裂谷系—陆表海—大陆的发展演化,又受到多期造山特别是空前强烈的燕山期陆内活化造山,并且是一个世界级钨地球化学块体,构成了优越的成矿基因;② 主要成矿特征：包括华南洋及其陆缘弧盆残体成矿,南华间冰期与冰后期大规模沉积成矿,多期大规模S型岩浆以钨为首的有色、铀、贵金属、非金属成矿,I型岩浆以铜为首的铁、有色、贵金属成矿以及钦杭成矿带超大矿床集群与“深地”找矿之眼等;③ 燕山运动岩浆与成矿“核幔式”时空演化规律以及多体系复合构造格局与陆洋左行扭动与洋壳俯冲为主导并有板内挤压、地壳蠕散相复合的动力学机制。