Prediction of local ore recoveries and ore-waste ratios at the silver bell uranium mine     

R. Froidevaux  A. G. Journel 《Mathematical Geology》1982,14(6):645-660

Geostatistical estimation techniques were customized to allow forecasting of production figures at the Silver Bell uranium mine (Uravan District).Surface drill hole data were used to provide a block model of kriged estimators of average uranium grades. Figures for recoverable ore grade and the ore-waste ratio are then deduced from regressive curves previously obtained from underground information and production data. Cross-validations of the entire model were performed and were found positive.  相似文献   

东川泥石流站开放以来的回顾与展望     

杜榕桓  康志成 《山地学报》1991,(3)

本文扼要介绍了中国科学院东川泥石流观测研究站对外开放三年来,在泥石流观测试验研究和防灾减灾工作中的新进展,同时也简述了站设基金课题、国家基金课题和中外合作交流项目的进展情况,并对今后的观测研究工作提出了展望和建议。  相似文献   

Finite element formulation and algorithms for unsaturated soils. Part I: Theory     

Daichao Sheng  Scott W. Sloan  Antonio Gens  David W. Smith 《国际地质力学数值与分析法杂志》2003,27(9):745-765

This paper presents a complete finite‐element treatment for unsaturated soil problems. A new formulation of general constitutive equations for unsaturated soils is first presented. In the incremental stress–strain equations, the suction or the pore water pressure is treated as a strain variable instead of a stress variable. The global governing equations are derived in terms of displacement and pore water pressure. The discretized governing equations are then solved using an adaptive time‐stepping scheme which automatically adjusts the time‐step size so that the integration error in the displacements and pore pressures lies close to a specified tolerance. The non‐linearity caused by suction‐dependent plastic yielding, suction‐dependent degree of saturation, and saturation‐dependent permeability is treated in a similar way to the elastoplasticity. An explicit stress integration scheme is used to solve the constitutive stress–strain equations at the Gauss point level. The elastoplastic stiffness matrix in the Euler solution is evaluated using the suction as well as the stresses and hardening parameters at the start of the subincrement, while the elastoplastic matrix in the modified Euler solution is evaluated using the suction at the end of the subincrement. In addition, when applying subincrementation, the same rate is applied to all strain components including the suction. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

WAP手机无线授时技术的模拟实现     

赵当丽  杨廷高 《时间频率学报》2002,25(2):118-123

介绍了无线应用协议(WAP)的工作原理、体系结构以及WAP的新应用——WAP手机无线授时的模拟实现。它是通过无线通信协议,以无线标记语言编写主程序,采用动态连接的方式调用VC 的时间通信程序来完成WAP手机的无线接时。对于用户来说,只要拥有具有WAP功能的手机,键入他要访问的WAP内容服务器的统一资源定位器(URL),就可以非常快捷、方便地获得时间信息服务。  相似文献   

山东省土地利用动态遥感监测应用研究   总被引：1，自引：0，他引：1       下载免费PDF全文

王德保  陈宝行  李高岗  崔淑文  赵秀珍  张凡荣 《山东国土资源》2003,19(3):43-47

该项目采用PCI V8.1遥感图象处理软件，对SPOT，TM，ETM卫星数据进行了校正、配准、镶嵌和多源多时相遥感数据融合，采用3种方法对土地利用变化信息进行提取，通过野外调查验证和GPS实地测定对变化图斑的空间数据进行精确定位，实现了RS与GPS的有机结合，提高了监测成果的准确性和可靠性，获得了快速、准确、翔实的矢、栅、属一体化监测成果。  相似文献   

传感器信号调制脉冲序列抽样频率的确定     

吴凡 《广东海洋大学学报》2003,23(1):51-56

通过对传感器输出信号波形有无振荡进行分类 ,依据传感器响应时间的定义 ,分别找到一阶、二阶及理想动态传感器的频带上限与动态响应时间两者间的关系式 ;提出了传感器“受激系数”的概念 ,推导出输出信号波形有无振荡两种传感器之间的比例关系。并通过一个数值例子 ,说明所推导出关系式的应用。  相似文献   

自由能密度上限及毫秒级射电尖峰的“饱和”机制     

黄光力  徐民健 《中国天文和天体物理学报》1989,(4)

本文首先介绍了热力学自由能上限的普遍公式及其推导思想,然后应用于非热电子束的具体形式,从而估计太阳射电活动中的毫秒级尖峰辐射的“饱和”能量;在此基础上,进一步为饱和时间问题作一般性的讨论;最后,在把尖峰“饱和”的几种机制进行了比较之后提出:由于尖峰能量远未达到非线性饱和的水平,因此,由某种外部因素(例如加速机制等)所导致的高能电子束的非均匀性可能是一种较为合理的模型。  相似文献   

Long-term growth of the oil industry in the United States     

Arthur FitzPatrick  Brian Hitchon  J. R. McGregor 《Mathematical Geology》1973,5(3):237-267

A number of growth models have been developed and used in an attempt to project the historical pattern of oil activities to some estimate of their upper limit. Techniques are outlined for the estimation of parameters of the logistic and Gompertz curves. Factor analysis indicated a close relationship between production and demand, whereas annual discoveries and discoveries classified by year of discovery tended to comprise unique factors which were indifferent to changes in time. The growth models projected relatively high values for ultimate demand and production in comparison to the figures for ultimate reserves. Inasmuch as these trends seemed to be occurring independently, some reconciliation of the results was necessary. Using the highest projections of estimates for reserves suggests that over 420 billion barrels of oil in place will eventually be discovered in the United States, with perhaps 200 billion barrels of this eventually to be proved in the form of reserves. Projections for production were higher, corresponding to a trend indicating high levels in demand for crude oil. The only credible long-term estimate of demand was given by a bounded exponential growth model, in which ultimate cumulative demand for crude oil would reach about 416 billion barrels. These figures imply that over 150 billion barrels of oil would be imported into the United States from 1970 to 2070. Provided the time pattern for one of the variables has been determined, then estimates of the other variables probably would be facilitated because of the high interrelationship between variables. Models are suggested in which accurate pivotal forecasting in the short term might be possible—assuming the particular future trend in some of the independent variables has been predetermined.Research Council of Alberta Contribution No. 596.  相似文献   

RBF神经网络的汛期旱涝预报方法研究   总被引：11，自引：8，他引：3       下载免费PDF全文

王艳姣  张鹰  邓自旺  宋德众 《热带气象学报》2005,21(1):100-106

分析广州2003年1～6月的SO2、NO2和PM10指数,发现(1)SO2、NO2和PM10具有非常好的同步变化关系,且以NO2和PM10的相关最大。(2)从月平均值来看,PM10是整个时段的主要污染物,SO2次之,NO2最小(1月除外);PM10和NO2呈现出逐月减小趋势,SO2变化平稳。主要讨论PM10指数的变化。(3)从月方差值来看,SO2、NO2和PM10的最大值均在1月,次大值在2月。(4)给出了几种地面气压型,结论显示主要清洁时段出现在锋区强风型,主要污染时段出现在脊内回流型。在脊内回流型下,若由前期的静风转吹东南(从东到南)风时,指数会增大。  相似文献   

Modified precise time step integration method of structural dynamic analysis   总被引：2，自引：1，他引：1  

汪梦甫  周锡元 《地震工程与工程振动(英文版)》2005,4(2):287-293

The precise time step integration method proposed for linear time-invariant homogeneous dynamic systems can provide precise numerical results that approach an exact solution at the integration points. However, difficulty arises when the algorithm is used for non-homogeneous dynamic systems, due to the inverse matrix calculation and the simulation accuracy of the applied loading. By combining the Gaussian quadrature method and state space theory with the calculation technique of matrix exponential function in the precise time step integration method, a new modified precise time step integration method （e.g., an algorithm with an arbitrary order of accuracy） is proposed. In the new method, no inverse matrix calculation or simulation of the applied loading is needed, and the computing efficiency is improved. In particular, the proposed method is independent of the quality of the matrix H. If the matrix H is singular or nearly singular, the advantage of the method is remarkable. The numerical stability of the proposed algorithm is discussed and a numerical example is given to demonstrate the validity and efficiency of the algorithm.  相似文献