金沙江下游水文泥沙信息系统设计与实现

采用了ArcEngine组件,建立了金沙江下游水文泥沙信息系统,实现了以GIS为基础的水文泥沙数据、河道地形数据、河道水质数据的查询、编辑、二维三维数据表现、水文泥沙基础分析等功能。     

CORS系统建设中数据通讯及组网问题

主要详细阐述了GNSS连续运行基准站系统（CORS）建设时,基准站到数据处理中心、数据处理中心到移动站通讯链路的建立方式和方法。根据CORS系统的应用情况以及固定参考站数量对通讯线路的构建方式以及组网方式进行了详细列表比对,并对无线宽带和3G通讯技术在今后的CORS系统通讯组网的应用进行了前瞻和简介,以供相关技术人员参考。     

Application of the geographical information systems approach to watershed mass balance studies

This study was undertaken to test the utility of a geographical information systems (GIS) approach to problems of watershed mass balance. This approach proved most useful in exploring the effects that watershed scale, lithology and land use have on chemical weathering rates, and in assessing whether mass balance calculations could be applied to large multilithological watersheds. Water quality data from 52 stations were retrieved from STORET and a complete GIS database consisting of the watershed divide, lithology and land use was compiled for each station. Water quality data were also obtained from 7 experimental watersheds to develop a methodology to estimate annual fluxes from incomplete data sets. The methodology consists of preparing a composite of daily flux data, calculating a best fit sinusoid and integrating the equation to obtain an annual flux. Comparison with annual fluxes calculated from high resolution data sets suggests that this method predicts fluxes within about 10% of the true annual flux. Annual magnesium fluxes (moles km⁻² yr⁻¹) were calculated for all stations and adjusted for fluxes from atmospheric deposition. Magnesium flux was found to be a strong function of the amount of carbonate in the watershed, and silica fluxes were found to increase with the fraction of sandstone present in the watershed. All fluxes were strongly influenced by mining practices, with magnesium fluxes from affected watersheds being 6–10 times higher than fluxes from comparable pristine watersheds. Mining practices enhance chemical weathering by increasing the surface area of unweathered rock to which water has access and by increasing acidity and rate of mineral weathering. Fluxes were also found to increase with watershed size. This scale dependence is most likely caused by the sensitivity of weathering fluxes to even minor quantities of carbonates, which are likely to be found in all lithologies at larger scales. Mass balances were carried out in watersheds where gauged sub-watersheds made up more than 95% of the area. The calculations show large magnesium flux and water balance discrepancies. These errors may be a result of significant groundwater inputs to streams between gauges. The results suggest that improvements in how we measure discharge and estimate fluxes may be required before we can apply mass balance techniques to larger scales. © 1997 John Wiley & Sons, Ltd.     

考虑耦联影响的二次结构体系减震分析

建立了基础隔震的主次结构体系耦联运动方程,开发了动力分析程序PS—BASE．FOR,对一典型结构的二次结构绝对加速度反应谱与相对位移反应谱计算分析表明,主体结构隔震或同时增大二次结构阻尼,是取得二次结构较好抗震性能的有效途径,增大主体结构的隔震阻尼对二次结构略有不利影响。     

ESTIMATION OF SOIL PARAMETERS FOR ASSESSING POTENTIAL WETNESS: COMPARISON OF MODEL RESPONSES THROUGH GIS

A geographic information system (GIS) is utilized to model wetness potential for a portion of Uwharrie National Forest, North Carolina. The wetness index is derived from TOPMODEL, a hillslope-scale runoff simulation model. The wetness index is a distributed-parameter model, with the input parameters obtained from a digital elevation model (DEM) and Soil Conservation Service (SCS) soils data. The primary objectives of the research are to: (1) compare methods of estimating soil parameters for input into the wetness potential model; and (2) determine how the model outputs vary spatially as a consequence of different methods of estimating soil parameters. Three methods of estimating soil parameters are used: (a) assuming uniform soil properties; (b) using SCS data presented as ranges; and (c) using alternative literature-based estimates of soil parameters. Results indicate that the wetness model responds similarly regardless of how the soil parameters are estimated, but differences in the spatial variability of the wetness potentials occur as a result of estimating soil parameters through alternative approaches. Correlation, pair-wise regression and analysis of regression residuals are used to compare model responses within a GIS environment.     

Dynamical bispherical separability and physical realizability

The Stäckel form of potential required for separability of the equations of motion is examined in relation to Poisson's equation for a finite mass gravitational system whose mass is spatially concentrated with a density which is everwhere finite.     

发展中地区银行业空间系统变化--以河南省为例

基于对中国发展中地区的河南省的第一手调查数据,对经济水平较低、受外部影响较小但增长迅速的内陆省份银行业空间系统变化进行了量化分析和解释。结果表明,与国际上发达国家相同,中国发展中地区的国有银行业逐步向中心城市集中。其中,作为区域中心的地级城市的地位上升最为突出。其形成原因主要与制度变化有关;而区域经济的发展差异,又是促进该趋势的直接诱因。这一观点通过混合OLS模型模拟得到证明。城市内部的银行业区位变化,具有一些与发达国家的不同之处。区域经济快速发展带来了中心城市的迅速拓展。同时经济结构调整,又带来了城市内不同地区经济发展水平的变化。由此形成了银行业区位的不断扩散,新兴快速增长的地区,迅速吸引了一批银行的建立。对郑州市58家银行网点的调查表明,在1978年之前,银行网点设立十分遵循计划体制的安排;而在1979年以后,邻近地段“人均收入水平高：决定着相当一部分银行网点的布局。这从微观角度佐证了河南省的分析结论。金融系统的集中格局,为非中心地区经济发展带来的不利影响,应该给予关注。     

海底表面磁源瞬变响应建模及海水影响分析

根据电磁场理论,推导了磁偶源和接收点均位于海水中时层状海底模型的频域电磁场响应一般表达式,并通过此式,得到了海水为均匀半空间和有限海水深度两种情况下,垂直磁偶极装置、中心回线和重叠回线分别置于均匀半空间海底表面时的瞬变电磁响应（磁场和感应电压）表达式. 这些表达式将瞬变响应和海底的电导率等参数有机联系在一起,为海底瞬变电磁法的正演计算和反演解释提供了理论基础. 仿真计算表明,海水的存在不仅使得瞬变响应曲线形态发生变化,而且影响其对海底电导率的分辨能力.     

DISTRIBUTED NUMERICAL RAINFALL–RUNOFF MODELLING IN AN ARID REGION USING THEMATIC MAPPER DATA AND A GEOGRAPHICAL INFORMATION SYSTEM

The rainfall–runoff process consists of an excess rainfall process and a runoff concentration process. A transient one-dimensional finite difference model describing the partitioning of precipitation between surface runoff, soil moisture storage and deep percolation, through the coupling of saturated–unsaturated zones, has been implemented in a geographical information system including data on vegetation cover derived from the Landsat Thematic Mapper. The model has been used to simulate both the rainfall excess and the resultant outflow hydrographs for a small arid zone drainage basin in the Andean region of Argentina. The overall hydrograph shape, peak discharge, runoff volume and flow duration are predicted within a relative squared error of 13.2%. The spatial input data and the model structure are discussed and suggestions for applications to larger complex basins and for future refinements in the technique are presented.     

珠江深水扇系统沉积和周边重要地质事件

最近的研究发现了位于南海北部珠江口外白云凹陷陆坡深水区的珠江深水扇系统。珠江深水扇系统以珠江为沉积物源、以持续深沉降的白云凹陷为沉积古地理背景、以与全球海退型海平面相反的相对海侵型海平面变化的沉积层序构成了其发育演化的特殊性,并留下了控制沉积的周边重要事件的记录。23.8 Ma等界面沉积速率和岩石地球化学特征均有突变,反映出物源区的变化,可能折射出与青藏高原隆升、南海扩张有关的重要事件,使得古珠江骤然向西部高原拓展,甚至较今天的珠江流域范围还广阔;承载珠江深水扇系统的白云凹陷持续沉降形成了陆坡内盆地,导致21~10.5 Ma BP多个层序深水扇垂向叠置充填的特殊沉积建造;根据60多口井资料建立的相对海平面变化曲线,具有与全球海平面变化相一致的三级旋回和不一致的二级旋回。如果能对珠江深水扇系统实施综合大洋钻探获取更为全面和准确的资料,开展珠江深水扇沉积作用与白云凹陷沉降的深部机制、珠江流域演化、海侵型相对海平面变化的耦合性等研究,将有利于揭示南海扩张、边缘海沉积、海平面变化、中国西部高原隆升事件的相关联系和形成机制。