Comparison of dissolved and particulate arsenic distributions in shallow aquifers of Chakdaha, India, and Araihazar, Bangladesh

Background  

The origin of the spatial variability of dissolved As concentrations in shallow aquifers of the Bengal Basin remains poorly understood. To address this, we compare here transects of simultaneously-collected groundwater and aquifer solids perpendicular to the banks of the Hooghly River in Chakdaha, India, and the Old Brahmaputra River in Araihazar, Bangladesh.     

浅谈工程测量学的发展

对工程测量学的地位和应用领域,通用和专用仪器的发展,在理论和实践上进行了归纳和总结。简要地叙述了工程测量在国内外的发展情况及其发展趋势。     

国内绝对重力观测比对

介绍2006年和2008年中国地震局地震研究所与国家测绘局第一测量大队绝对重力测量比对的概况,分析观测和比对结果表明,绝对重力仪FG5/214与FG5/232具有较好的一致性,二者几乎不存在系统误差.FG5/214与FG5/232具有较强的抗干扰能力,重复性很好,内符合测量精度为±(2～3)μCal.     

基于遥感技术的土地复垦工程量评价研究

随着全国范围内土地复垦工作的广泛开展,对于土地复垦项目的评价变得越来越重要。通过选取实验区域,获取实验区的相关实地数据及遥感影像,研究处理和解译实验区遥感影像,对影像进行分类处理,提取了土地复垦项目的工程量指标,并对其进行精度分析,建立了土地复垦项目的工程量评价体系,结果与实地数据一致,说明遥感评价方法具有实际可行性。     

“多对多”模式GPS台站网系统设计与应用分析

本文在分析GPS RTK定位工作模式的基础上,以苏州市为研究对象,讨论了＂多对多＂模式GPS台站网系统设计,研究了相应的操作规程,并进行了该模式下的定位试验,对定位结果的精度进行了分析,最后给出了结论。     

Changes in hydrogeological properties of the River Choushui alluvial fan aquifer due to the 1999 Chi-Chi earthquake, Taiwan

Changes in hydrogeological properties of the River Choushui alluvial fan aquifer before and after the 1999 Chi-Chi earthquake, Taiwan, have been identified using pumping tests. Three wells, SH2, YL2 and SC2, located in a compressional zone with high coseismic groundwater levels, were tested. The threshold of the aquifer deformation with respect to transmissivity (T) is greater than that with respect to storage coefficient (S). Decreases in the post-earthquake S are approximately 60% at SH2 and SC2, indicating aquifer compression after the Chi-Chi earthquake. Changes in the post-earthquake T range from 61% increase to 0.8% decrease. Moreover, results from anisotropy analysis of T at SC2 further illustrate that normal stresses induced by the Chi-Chi earthquake have consolidated soil particles. Soil particles dilated laterally after the earthquake, resulting in an increase of the equivalent T. The changes in hydrogeological properties have a considerable influence on spatiotemporal fluid pressure and horizontal groundwater movement, resulting in different amounts of drawdown during post-earthquake pumping.     

煤层气储层测井评价有关问题的讨论

煤层气的形成和储层的特性决定了煤层气储层评价的一系列关键参数,这些参数可用常规测井方法直接或间接获得。目前常规测井方法包括自然电位、双侧向（或感应）、微电极、补偿密度、自然伽马、声波时差、声波全波列、中子孔隙率以及井径测井等。选用不同测井方法采用线性回归或体积模型等方法,可以获得煤层气储层评价参数。     

渤海湾盆地埕岛油田缝洞型潜山油气藏构造及储层特征

埕岛油田古潜山油气藏为典型的缝洞型碳酸盐岩油气藏。埕岛地区经历了多期次的构造运动,并经受了多期次的断裂与剥蚀作用,为油气成藏创造了良好条件。埕岛油田古潜山可以划分为三个构造单元,即埕北20断层下降盘的西排山,上升盘的中排山和东排山,三个潜山带成帚状敛于凸起最南端,为几个二级构造单元交汇处,构造应力较发育。埕岛油田有三种储集空间类型:晶间孔隙、溶蚀孔洞和裂缝。     

初至层析静校正在复杂山地三维地震勘探中的应用

随着地形高差增大、地貌单元多变、近地表模型复杂,目前被广泛应用的初至折射静校正的精度已无法满足精细勘探的要求。初至层析静校正技术,由给定的初始模型进行正演,用射线追踪方法得到初始模型的初至波,利用该初至波和实际拾取的初至波进行比较,计算地表模型的修正量,反复迭代求得准确的地表模型。山西省国阳新能股份有限公司二矿390水平九采扩区地表标高940～1100m,地貌单元复杂,在对该区资料处理时,利用初至层析折射静校正,经9次迭代计算后,真实地刻划出近地表模型。在二种静校正技术对比中,初至折射静校正不但近地表模型精度低于层析折射静校正,而且其叠加剖面精细程度也远低于层析静校正,如在初至折射静校正叠加剖面同相轴上呈现的凹凸形态,在层析静校正叠加剖面并无显示,且后者剖面的信噪比也比前者明显提高。