航空物探在酸性岩岩性划分中的效果     

梁月明  黄旭钊  周道卿  徐昆  张洪瑞 《物探与化探》2007,31(6):520-525

北山地区近几年来开展的大比例尺、高精度航空物探(磁、伽马能谱)测量,为岩性分类提供了可靠的高分辨率基础资料,也为这一地区的地质矿产勘查提供了新的信息.以北山东段岩性构造填图酸性侵入岩分类为例,介绍航空物探岩性分类的技术方法及工作要点.  相似文献   

Installation of a vertical slurry wall around an Italian quarry lake: complications arising and simulation of the effects on groundwater flow   总被引：1，自引：0，他引：1  

D. A. De Luca  M. Lasagna  A. Morelli di Popolo e Ticineto 《Environmental Geology》2007,53(1):177-189

Slurry walls are non-structural barriers that are constructed underground to impede groundwater flow or manage groundwater control problems. The study area is in the Piemonte plain (Italy), close to the River Po. Quarrying works carried out below the piezometric surface created two big quarry lakes. The local groundwater system is characterized by a lower semi-confined aquifer, which is overlain by a semi-permeable bed of clayey peat (aquitard) and an upper unconfined aquifer. Locally, the peat fades away and the granulometry of this horizon becomes silty sandy. A planned enlargement of the quarry will increase the size and depth of the quarry lakes. So the aquitard bed between the two aquifers will be damaged, creating a mixing rate of groundwater. Such a procedure would not be compatible with the presence of two municipal wells upstream from the quarries. Consequently, the installation of a vertical diaphragm (slurry wall) is recommended to separate the aquifers and to act as a filter for the groundwater flowing from the unconfined to the semi-confined aquifer. To predict the consequences caused by the installation of the vertical diaphragm separating the unconfined aquifer and the semi-confined one, a specifically adjusted finite-difference model was used. The model showed a maximum rising of the water table equal to 12 cm, just upstream of the diaphragm and for a distance of about 100 m, and a maximum lowering of 2 cm just downstream of the diaphragm. However, the slurry wall would not cause any change in the piezometric head in the area where there are municipal wells and, hence, will not have any negative effect on the functionality of the municipal wells. Moreover, the migration of water from the unconfined aquifer through the vertical diaphragm will stimulate a series of attenuation and auto-depuration processes of eventual contaminants. These processes are due to the higher crossing time that the groundwater flow takes to go through the vertical barrier (t _a = 96.5 days, whereas for the horizontal semi-permeable layer t _a = 9.6 days). So, the vertical diaphragm can be a resolutive element, representing a mediation and separation factor between the unconfined and the semi-confined aquifers along the border of the quarrying areas, and a protective barrier for the water quality of the quarry lake and the semi-confined aquifer.  相似文献   

安徽省旅游星级饭店地域差异研究     

王娟  祝小迁  戴昕  李渊 《福建地理》2007,(1)

根据2000～2005年安徽省星级饭店统计资料,利用变异系数这一度量标准分析了安徽省饭店在时间序列上和星级结构上的地域差异,结果表明:随着时间的变化饭店总数在各市间的差异在渐渐缩小.星级结构上五星级饭店地域分异程度最大,其次依次为一星级、四星级、三星级和二星级,通过安徽省各市国内旅游收入区位商和餐饮住宿业就业人员区位商与各市星级饭店数量相对水平的比较,找出不符合一般趋势的城市加以讨论.最后,运用SPSS分析软件对安徽省17个地市的星级饭店发展水平进行聚类分析,并讨论了运行结果所分出的4类城市,提出了饭店业发展的若干建议.  相似文献   

Shape Similarity measures of Linear Entities     

ZhangQiaopin  LIDeren 《地球空间信息科学学报》2002,5(2):62-67

The essential of feature matching technology lies in how to measure the similarity of spatial entities.Among all the possible similarity measures,the shape similarity measure is one of the most important measures because it is easy to collect the necessary parameters and it is also well matched with the human intuition.In this paper a new shape similarity measure of linear entities based on the differences of direction change along each line is presented and its effectiveness is illustrated.  相似文献   

东西方文化差异的地理透视与整合分析     

袁本华  曹诗图 《世界地理研究》2001,10(1):98-103

本文从比较文化学与文化地理学的角度，较全面、系统地分析比较了东西文化的诸多差异，侧重剖析了东西方文化差异的地理原因，评介了“东化”与“西化”之争的基本观点，说明了东西方文化的关系及其发展前景。  相似文献   

Differences between Mean Sea Levels for the Pacific,Atlantic and Indian Oceans From Topex/Poseidon Altimetry     

Burša  Milan  Kouba  Jan  Müller  Achim  Raděj  Karel  True  Scott A.  Vatrt  Viliam  Vojtíšková  Marie 《Studia Geophysica et Geodaetica》1999,43(1):1-6

Geopotential values W of the mean equipotential surfaces representing the mean ocean topography were computed on the basis of four years (1993 - 1996) TOPEX/POSEIDON altimeter data: W = 62 636 854.10m ² s ^–2 for the Pacific (P), W = 62 636 858.20m ² s ^–2 for the Atlantic (A), W = 62 636 856.28m ²s^–2 for the Indian (I) Oceans. The corresponding mean separations between the ocean levels were obtained as follows: A – P = – 42 cm, I– P = – 22 cm, I – A = 20 cm, the rms errors came out at about 0.3 cm. No sea surface topography model was used in the solution.  相似文献   

顾及密度差异的河系简化   总被引：7，自引：2，他引：7  

张青年 《测绘学报》2006,35(2):191-196

河系简化是地图综合中经常需要处理的任务,其难点主要在于依据上下文环境对河流进行结构化选取,以保持河网密度差异等宏观特征。提出一种新的河流等级规则,依据河流的各级支流的数量确定河流的等级,以反映河流的密度差异;设计一种结合河流等级、长度与所在层次的综合指标进行河流选取;探讨在自动构建河系树的基础上计算河流等级、所在层次等指标的方法;最后使用综合指标进行河流结构化选取试验。结果表明,以新等级规则为基础的综合指标切实可行,能够在一定程度上保持河网密度的区域差异。  相似文献   

人工神经网络在色彩变换中的应用   总被引：1，自引：0，他引：1  

徐艳芳  刘文耀  武兵  黄敏 《武汉大学学报(信息科学版)》2006,31(9):799-802

给出了一种针对数字彩色硬拷贝的输出设备，建立了由CIE色度值到设备控制值色彩变换的神经网络方法。基于蒙版方程的颜色传递机理，由色度密度变量实现色彩变换。结果表明，该色彩变换对各种色调均有较明显的校正作用，且保持了高饱和色的饱和度。  相似文献   

泰安市世行贷款二期项目区地下水监测研究     

周兰云  尚艳丽  马传顺 《地下水》2006,28(2):53-54,57

为合理开发利用地下水资源提供科学依据,确保地下水资源可持续利用,防止由于超采地下水而诱发环境危害,对泰安市世行贷款二期项目区地下水动态变化规律、水资源的分布特征进行了分析研究,提出了地下水合理开发利用的建议.  相似文献   

河南省区域经济差异及时空特征分析   总被引：16，自引：1，他引：16  

雒海潮  苗长虹 《云南地理环境研究》2006,18(4):62-68

以SPSS统计分析软件和GIS技术为基础，以县域为研究单位，分析改革开放以来河南省县域经济差异变化的时间特征、空间格局及其变化过程，结果表明：（1）河南县域经济发展水平绝对差异扩大，相对差异起伏发展．两极分化显现；（2）在空间上经济发展水平形成了以西北部为中心，向东南递减的核心圈层结构；（3）经济发展现状水平与经济发展初始水平和发展速度呈明显的相关性，现状发展水平较高的地区，其经济发展初始水平和发展速度一般都较高。对县域经济差异的成因，从区域发展战略、资源条件、区位、投资政策和市场化程度等方面进行了揭示，最后提出了对河南区域经济发展的政策建议。  相似文献