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Geochemical Information Indicating the Water Recharge to Lakes and Immovable Megadunes in the Badain Jaran Desert 总被引:1,自引:0,他引:1
CHEN Jiansheng ZHAO Xi SHENG Xuefeng Wang Jiyang GU Weizu and CHEN Liang State Key Laboratory of Hydrology-Water Resources Hydraulic Engineering Hohai University Nanjing Jiangsu E-mail: jschen@hhu.edu.cn Institute of Isotope Hydrology Research Hohai University Nanjing Jiangsu Institute of Geology Geophysics Chinese Academy of Sciences Beijing 《《地质学报》英文版》2005,79(4):540-546
1 Introduction The Badain Jaran Desert, located in western Inner Mongolia, China, has a unique landscape containing 144 lakes (72 of which are still watery) with a total water area of about 23 km2, and the world’s highest stationary sand dunes with a height between 200 m and 500 m. Much attention has been paid to the water recharge of the desert in the past decade. Investigations on the resources of water system there have been performed continuously since the early 1990s, which lead to th… 相似文献
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塔里木盆地上泥盆统及石炭系包括5个组,自下而上分别为上泥盆统东河塘组和甘木里克组,石炭系巴楚组、卡拉沙依组和小海子组。其中东河塘组和甘木里克组地质时代为晚泥盆世,巴楚组地质时代为早石炭世杜内早中期,卡拉沙依组地质时代为晚杜内中期至巴什基尔期,小海子组地层时代为巴什基尔末期至莫斯科早期。岩石类型有碎屑岩和碳酸盐岩,还有膏盐岩,并夹薄层火山碎屑岩。沉积相主要为海陆过渡相组合,包括河流、三角洲、滨岸、浅海、碳酸盐岩台地、台地边缘6种相和12种亚相及33种微相。晚泥盆世东河塘期至石炭纪发生过4次较大的海侵,海侵范围由下而上逐渐增大,至晚石炭世小海子期海侵规模最大。东河塘期开始海侵,海水由西而东侵入,此时周缘碎屑物质供应充分,主要为无障壁海岸和障壁海岸沉积,西南缘为浅海相沉积。巴楚期晚期,海侵范围进一步扩大,物源向北或北东方向退却,陆源碎屑物质注入急剧减少,形成了一套富含生屑的碳酸盐岩地层,发育了开阔台地和局限台地亚相沉积。卡拉沙依期中期海侵规模比巴楚期更大,海水深度加大,西部为开阔台地亚相沉积,其余地区为局限台地亚相沉积。卡拉沙依期晚期和小海子期海侵达最大,向东扩展,大部分地区为开阔台地亚相沉积,东部地区为局限台地亚相沉积,塔北大部分地区缺失。 相似文献
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提出一种基于接收信号强度的源节点定位算法,无需事先已知源节点的发射功率以及环境中的路径损耗指数。该算法首先对接收信号强度的路径损耗模型进行两次差分,消去与源节点发射功率相关的模型参数和路径损耗指数,然后利用最小二乘准则来估计源节点的位置。通过仿真数据评估该算法的定位精度,并与其他源节点定位算法进行比较。 相似文献
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天气雷达接收功率标定的检验方法探讨 总被引:4,自引:0,他引:4
通过把测试信号输入功率换算到雷达天线喷口处接收功率的计算,由雷达气象方程可计算出其雷达反射率z值,和经雷达接收功率定标后,此测试输入功率在雷达正常观测模式显示的雷达反射率z值相比较,以检验天气雷达接收功率标定的误差是否满足技术要求。 相似文献
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Improvements of corner frequency and scaling factor for stochastic finite-fault modeling 总被引:1,自引:0,他引:1
In this paper, three existing source spectral models for stochastic finite-fault modeling of ground motion were reviewed.
These three models were used to calculate the far-field received energy at a site from a vertical fault and the mean spectral
ratio over 15 stations of the Northridge earthquake, and then compared. From the comparison, a necessary measure was observed
to maintain the far-field received energy independent of subfault size and avoid overestimation of the long-period spectral
level. Two improvements were made to one of the three models (i.e., the model based on dynamic corner frequency) as follows:
(i) a new method to compute the subfault corner frequency was proposed, where the subfault corner frequency is determined
based on a basic value calculated from the total seismic moment of the entire fault and an increment depending on the seismic
moment assigned to the subfault; and (ii) the difference of the radiation energy from each subfault was considered into the
scaling factor. The improved model was also compared with the unimproved model through the far-field received energy and the
mean spectral ratio. The comparison proves that the improved model allows the received energy to be more independent of subfault
size than the unimproved model, and decreases the overestimation degree of the long-period spectral amplitude. 相似文献
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南水北调供水的重点是城市,而城市用水最大的是工业,受水区工业用水占城市总用水的65.6%.遵照朱镕基总理关于南水北调工程“先节水后调水”的指示,开展受水区工业节水的分析工作意义重大。重点对黄淮海流域以及南水北调中、东线工程受水区的工业用水、节水现状、节水潜力及节水投资与效益等进行了分析。得出了区域工业节水在全国处在相对较高水平,工业节水的重点在现有工业及乡镇工业,但节水不能完全解决工业用水增长需求等结论。 相似文献
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