原始数据误差对放样点精度影响的探讨

本文在文献[3]的基础上,进一步探讨了工程测量中原始数据误差对放样点精度影响的问题。首先,讨论了施工控制网中原始数据误差存在的形式、特点以及它们对放样点精度影响的传播规律,并建立了关于相对放样点位精度的矩阵公式。在此基础上,对现有的几种常用放样方法中原始数据误差的影响进行了分析和计算。结果表明,在施工放样测量工作中,应该密切注视原始数据误差的影响,并对此问题提出一些合理的建议。     

青藏高原对冷空气爆发影响的个例分析(一)

本文通过对1979年4月10—13日在我国的一次寒潮爆发过程进行了有、无地形及修改地形的数值试验和对比分析,发现高原地形对冷空气活动强度及路径等有明显的影响:(1)由于高原地形的存在使冷空气快速沿地形边缘向南推移,冷锋偏南,给我国平原地区带来较大的降温及较多的降雨。(2)这种冷锋的移动快而达到很偏南的纬度主要是低层冷空气沿高原地形边缘绕流所产生的。(3)如果高原大地形不存在,这时冷空气直侵印度,给印度北方带来强降温。     

准各向异性粘弹介质地震波的数字仿真

本文论述准各向异性粘弹波动方程有限元数值解地震波响应的原理与计算方法,并给出地震衰减因子与方程中粘滞系数的计算关系式。列出了所研制的地面记录地震剖面与井中记录垂直地震剖面,以及波场时间切片图、散度与旋度图、应变能与动能的时间切片图。本方法适于任意分层形态且层间物性参数为强间断的实际地震剖面的仿真,旨在研究正问题以实现反问题。     

一种快速鉴定商品性钨矿石的方法

本文介绍了商品性钨矿样品的溶矿、染色试验方法和理论原理。该方法简便、快速,能准确地取得钨矿体积的百分数,较精确地计算WO_3的百分含量,满足钨矿商品性指标的要求。经检验证实,方法具有实用性,可以把住钨矿收购的质量关,并已收到了显著的经济效益。     

用相关系数估计导线点误差椭圆参数

用比例误差k和导线边数n所表示的坐标相关系数r,当导线走向α=45°时,误差椭圆大小、形状与相关系数之间存在一个简单的数学关系式,在导线设计时可用作精度估算。     

Dimension and entropy in the soil-covered landscape

Both the Hausdorff dimension and the K-entropy supply a measure of the irregularity of the landspace surface. The relationship between the two measures is investigated over a variety of terrains in Britain and a method of calculating the entropy is checked against an independent estimate of the dimension with reasonable agreement. The calculation of the K-entropy requires that the landscape surface be represented by an homogenous ergodic random field. This condition is satisfied by the tendency of soil-covered terrains to progressively approximate to a form well represented by a Gaussian field. Gaussian random fields can either be very smooth, possessing derivatives of all orders at every point or they are highly irregular and non-differentiable everywhere. Within the regular conceptualization the Rice-Kac theory is used to predict the numbers of crossing points and the extent of excursion sets. These predictions are tested against an example terrain from the High Weald of East Sussex with very good agreement, apart from predictions of local maxima. A worked example of the calculation of the K-entropy is given as an appendix. The potential role of information theory in geomorphology extends beyond the use made of entropy in this investigation. In particular ergodic theory has important practical and theoretical implications.     

Simulation of the time-space evolution of an extratropical cyclonic precipitation field over USA

The time-space evolution of an extratropical cyclonic precipitation field over U S A is simulated in a stochastic setting as outlined in Kavvas et al. (1988). The birth of a cyclonic storm is characterized by the simultaneous birth of a cyclone center and births of subsynoptic precipitation areas (SPA) at preferred locations around the cyclone center. The precipitation cores and cells which are used as the fundamental building blocks of the SPAs are approximated by circular precipitation areas (CPA) of different sizes. The time space evolution of the precipitation field after the birth is governed by (1) the movement of the synoptic cyclone described by the cyclone center trajectory, (2) independent nonidentically distributed random velocities of the individual CPAs relative to the cyclone center, (3) the births of new CPAs in time and space relative to the cyclone center, (4) the independent evolution in time of the individual spatially uniform intensities of the existing CPAs, (5) the expansion and shrinkage of the existing CPAs in the course of movement and (6) the dissipation (death) of a random number of existing CPAs within the cyclonic system. The computer simulation, the results of which are presented in this paper, successfully reproduced the general mesoscale and synoptic scale features of the radar detected cyclonic rain fields as observed by Austin and Houze (1972), Houze et al. (1976), Hobbs (1978), Hobbs and Locatelli (1978), Houze (1981), Houze and Hobbs (1982) and others.     

层状含水系统R—C电网络模拟方法

本文论述了R-C电网络模型的基本原理及模拟装置,分析了不同类型的层状含水系统。根据榴似性原理,建立了不同类型的电网络模型。在此基础上,预测了内蒙古某露天煤矿的矿坑疏干涌水量,取得了比较满意的结果。     

城市地下水可采资源与管理模型研究中的几个问题：以河南漯河市为例

文章以漯河市为例说明了城市地下水最大可采资源的确定和开发管理中遵循不断变化着的实际情况,走科研与生产相结合道路的必要性。全文分3个方面介绍了开采条件下的人工串层补给,随机边界条件及地下水管理模拟中常见的几个核心问题的处理。文章最后强调,地下水数值模拟中辅以同位素年龄研究的重要性。     

探采结合和数值模拟

本文用一个工程实例说明正确运用数值模拟,可代替现行水文地质勘探阶段的开采性抽水试验,从而可节省资金和缩短勘探及建设工期。文中强调。务使所用数学模型尽可能地逼近和反映水源地所在水文地质单元的原型。否则,模型易失真,必导致资源评价的失败。