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991.
基于栅格数字高程模型自动提取黄土地貌沟沿线技术研究 总被引:36,自引:2,他引:34
从数字高程模型中提取具有精确定位特征的连续的沟沿线是构建黄土沟壑丘陵地区土壤侵蚀,泥沙搬运和径流过程的空间分布式机理-过程模型的关键技术。本文提出了基于地貌形态学特征的地貌提取技术,在提取具有代表性的黄土丘陵沟壑区山西离石王家沟流域汇流网络的基础上,自动提取了该流域完整的沟沿线,得到了满意的结果。 相似文献
992.
Aimed at the initial value problem of the particular second-order ordinary differential equations,y
=f(x, y), the symmetric methods (Quinlan and Tremaine, 1990) and our methods (Xu and Zhang, 1994) have been compared in detail by integrating the artificial earth satellite orbits in this paper. In the end, we point out clearly that the integral accuracy of numerical integration of the satellite orbits by applying our methods is obviously higher than that by applying the same order formula of the symmetric methods when the integration time-interval is not greater than 12000 periods. 相似文献
993.
The EGO method, developed by Egozcue et al. and the SRAMSC method, originally developed by Cornell and later programmed by McGuire, to assess the seismic hazard, are compared for the low seismicity area Belgium, The Netherlands, and NW Germany. Using the same input data, the results of the EGO method without the majority criterion and the SRAMSC method with upper bound XII agree very well. The influence of the zoning is investigated for the EGO method. It is not necessary to define the zones for the EGO method so strictly as for the SRAMSC method, but too wide zones can give bad results. 相似文献
994.
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996.
灌注桩基础是珠江三角洲地区工业与民用建筑广泛采用的基础形式之一,但由于各种原因,发生质量问题的灌注桩基础屡见不鲜.本文简明地介绍了灌注桩基础工程质量事故概况、灌注桩质量检测和评价方法以及灌注桩质量事故处理的常用方法. 相似文献
997.
本文通过桩基工程实例 ,着重介绍了在工程桩施工过程中 ,对为遏制危及周围建筑物的影响所采取的有效防护措施 ,业已取得了明显的效果 相似文献
998.
A mathematical model of the disturbance of the stationary geothermal field due to a three-dimensional perturbing body embedded near the surface of a two layered earth. The theoretical analysis is based on the generalized theory of the double-layer potential, similar to the boundary integral method likely to direct current geoelectricity problems. Special attention is paid to cases in which a pan of the body's surface is tangential to the planar boundaries of the substratum or of the surface of the earth The numerical calculations are performed for a three-dimensional prism using methods similar to the boundary element method (BEM). Numerous graphs are shown for the disturbance of the temperature field and of the heat flow on the surface of the earth and along vertical profiles (boreholes). 相似文献
999.
Preliminary study on weathering and pedogenesis of carbonate rock 总被引:23,自引:0,他引:23
Shijie Wang Hongbing Ji Ziyuan Ouyang Dequan Zhou Leping Zhen Tingyu Li 《中国科学D辑(英文版)》1999,42(6):572-581
South China is the largest continuous distribution area of carbonate rock in the world. The origin of the soils over the bedrock
carbonate rock has long been a controversial topic. Here further exploration is made by taking five soil profiles as examples,
which are developed over the bedrock dolomitite and limestone and morphologically located in upland in karst terrain in the
central, west and north Guizhou as well as west Hunan, and proved to be the weathering profiles of carbonate rock by the research
results of acid-dissolved extraction experiment of bedrock, mineralogy and trace element geochemistry. Field, mineralogical
and trace element geochemical characteristics of weathering and pedogenesis for carbonate rock are discussed in detail. It
is pointed out that weathering and pedogenesis of carbonate rock are important pedogenetic mechanisms for soil resources in
karst area, providing a basis for further researches on the origin of soils widely overlying bedrock carbonate rocks in South
China.
Project supported by the National Natural Science Foundation of China (Grant No. 498330003) and National Key Basic Research
Project (Grant No. 95pre-39). 相似文献
1000.
北京地区重磁数据计算机图像处理及地质效果 总被引:2,自引:1,他引:1
介绍了对北京地区重力和磁力数据进行计算机图像处理的技术及流程,解译了重磁数据图像处理结果,分析了重磁数据计算机图像处理的地质效果,得到了一些对北京地区成矿预测有益的新认识 相似文献