MODFLOW 2000 head uncertainty,a first-order second moment method

A computationally efficient method to estimate the variance and covariance in piezometric head results computed through MODFLOW 2000 using a first-order second moment (FOSM) approach is presented. This methodology employs a first-order Taylor series expansion to combine model sensitivity with uncertainty in geologic data. MODFLOW 2000 is used to calculate both the ground water head and the sensitivity of head to changes in input data. From a limited number of samples, geologic data are extrapolated and their associated uncertainties are computed through a conditional probability calculation. Combining the spatially related sensitivity and input uncertainty produces the variance-covariance matrix, the diagonal of which is used to yield the standard deviation in MODFLOW 2000 head. The variance in piezometric head can be used for calibrating the model, estimating confidence intervals, directing exploration, and evaluating the reliability of a design. A case study illustrates the approach, where aquifer transmissivity is the spatially related uncertain geologic input data. The FOSM methodology is shown to be applicable for calculating output uncertainty for (1) spatially related input and output data, and (2) multiple input parameters (transmissivity and recharge).     

红河干流大黑公水电站地质灾害危险性分析

大黑公水电站坝址及库区处于红河深大断裂带，面临诸多工程地质灾害地质问题，把研究区分为大、中、小三级5个不同地质灾害危险性区段，研究为电站建设预可研阶段工作提供指导性意见。     

论煤田地质报告中环保篇章的意义和内容

论述了编制煤田地质报告环保篇章的意义、潜在环境问题识别和预评价,概括介绍了环保篇章的内容,旨在推动和加强煤田地质报告环保篇章的编制工作,为管理机构、产业部门提供开发煤炭资源的决策依据,并为以后工作提供指导。     

UNIX操作系统与Internet网络

根据作者的工作实践，本文提出了ＵＮＩＸ操作系统在互联网络中的作用和对Ｉｎｔｅｒｎｅｔ网络发展的重要技术及其应用进行了介绍。     

网络专题地图服务平台的设计与实现

空间信息共享和互操作是GIS发展永恒的主题,本文主要研究了网络专题地图服务平台的设计与实践,从数据目录管理、多源数据节点的远程访问与调度、专题地图的按需动态生成与发布等关键技术着手,研究实现了面向用户的空间信息与行业统计信息的集成共享与可视化。利用ASP．NET创建了网络专题地图服务门户,验证了所提出的框架体系和关键技术的合理性和可行性。     

GPS软件接收机捕获算法的研究

为了提高GPS软件接收机信号捕获的速度,提出了一种GPS卫星C/A码信号捕获的新方法(这种方法具有Gold码的性质)。并证明了多颗卫星信号的相关性可以在同一次相关性计算过程中同时处理完成,在一次捕获卫星信号过程中可同时捕获多颗卫星信号。     

Organotin accumulation in an estuarine food chain: comparing field measurements with model estimations

The bioaccumulation model OMEGA (optimal modelling for ecotoxicological applications) is used to explore accumulation of organotins in the Western Scheldt food chain, consisting of herbi-detritivores, primary and secondary carnivorous fish and a piscivorous bird. Organotins studied are tributyltin (TBT) and triphenyltin (TPT) and the respective di- and mono-organotin metabolites. Empirical elimination rate constants are compared to model predictions for organic substances and metals. It is found that field bioaccumulation ratios are higher than predicted based on elimination kinetics relevant for organic compounds. The results indicate that uptake of organotins mainly occurs via hydrophobic mechanisms, whereas elimination may occur via metal-like kinetics. This results in very low elimination rates, which are comparable to model predictions for metals.     

澳大利亚海上坎宁盆地油气地质特征及勘探潜力

以石油地质理论为基础,利用区域地质、地震以及钻井资料,对澳大利亚西北陆架海上坎宁盆地的沉积构造演化以及石油地质特征进行了综合分析。研究表明,盆地经历了陆内裂陷期、克拉通边缘坳陷期、被动裂陷期和漂移期4个演化阶段,主要充填了中生界沉积地层。目前,已证实发育2套生储盖组合,已发现油气均集中在三叠系含油气系统中,平面上仅在Bedout坳陷内分布。盆地整体勘探程度较低,油气地质综合分析表明,Bedout坳陷以及Rowley坳陷具有良好的勘探前景。