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251.
The ground water flow path of the coastal area in the Yellow Sea, Korea, was interpreted using both the cross‐correlation analysis of hydraulic properties and the principal component analysis (PCA) of ground water chemistry. Data was obtained from observation wells in the underground liquefied petroleum gas (LPG) cavern constructed in the coastal area of Pyeongtaek. Cross‐correlation results showed that the operating pressure became more influenced on artificial factors for the variation of the groundwater level of the study area (45–66% of correlation coefficient) even though its affecting area was limited to the region with fractures or faults, and also showed that the delay time from the variation of operating pressure to the fluctuation of ground water level were relatively long periods (28–31 days). Three hydrogeochemical events (encrusted cement dissolution, host rock dissolution, and seawater intrusion), which were dominantly influenced on ground water quality, could be induced from the result of PCA. Quantitative evaluation for these events using the mixed equation with principal component scores suggest that the dissolution of encrusted cement materials was the predominant factor (39·0% of the total mixed proportion) to change the chemical composition of the seepage water during the ground water flow from the observation wells to the cavern. Integration of the statistical results also imply that ground water flow and hydrogeochemistry were predominantly affected by artificial factors such as cavern operation pressure and dissolution of encrusted cement materials, which were interdependent factors on the observation wells with high cross‐correlation coefficients and pH. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
252.
Policy and Practice Progress of Watershed Eco-compensation in China   总被引:2,自引:0,他引:2  
The ecological protection of the watersheds in China is being confronted with a lot of problems such as soil and water erosion, water pollution at present. Therefore watershed eco-compensation is becoming a question of common interest. Based on the analyses of the major problems and their origins in the watershed protection in China, the paper discusses the concerned policies including relative rules and laws, financial policies and water right transaction policies. Simultaneously the paper reviews the practices carried out in China, including the ecological construction project in the western China, the trans-provincial eco-compensation practice and the small watershed eco-compensation practice. According to the present situation of eco-compensation practices and the future policy requirement, this paper finally puts forward four key problems to be solved in the watershed eco-compensation of China in the future.  相似文献   
253.
This paper describes a 5 GHz VLBI survey in the southern hemisphere. The first observation of 23 extragalactic radio sources was conducted in November 1992. Twenty VLBI images were obtained, of which 15 sources show core-jet structure, one has a two-sided jet, and three sources are unresolved. No compact double source was found. Eleven of the 16 sources with core-jet (including a two-aided jet) show evidence of jet bending. In addition, four sources appear to be superluminal, of which three sources are new.  相似文献   
254.
The generalized Eddington approximation, obtained by the three-stream division of the radiation field, is used to compute the intensity falling on the nucleus head of a spherically-symmetric comet illuminated by parallel solar radiation.  相似文献   
255.
Understanding the past is the key to know thepresent and to predict the future. As a core project ofthe International Geosphere Biosphere Program, PastGlobal Changes (PAGES) aims to reconstruct theevolution history of global climate, global environ-ment and global ecosystem with resort to all kinds ofnatural records, so as to reveal the change rules(change processes, change amplitude and change rate)of the global environment and thus provide scientificbasis for predicting climate changes p…  相似文献   
256.
Progress in the Study of Deep Profiles of Tibet and the Himalayas (INDEPTH)   总被引:5,自引:0,他引:5  
This paper introduces 8 major discoveries and new understandings with regard to the deep structure and tectonics of the Himalayas and Tibetan Plateau obtained in Project INDEPTH, They are mainly as follows. (1) The upper crust, lower crust and mantle lithosphere beneath the blocks of the plateau form a "sandwich" structure with a relatively rigid-brittle upper crust, a visco-plastic lower crust and a relatively rigid-ductile mantle lithosphere. This structure is completely different from that of monotonous, cold and more rigid oceanic plates. (2) In the process of north-directed collision-compression of the Indian subcontinent, the upper crust was attached to the foreland in the form of a gigantic foreland accretionary wedge. The interior of the accretionary wedge thickened in such tectonic manners as large-scale thrusting, backthrusting and folding, and magmatic masses and partially molten masses participated in the crustal thickening. Between the upper crust and lower crust lies a large detachment (e.g  相似文献   
257.
本文根据甘肃省农村社会经济发展和地震环境特征,简要分析了甘肃农村民居主要建筑结构类型和抗震性能,结合近10多年来破坏性地震资料,总结了农村民居主要震害特点,提出了实施甘肃省农村民居地震安全工程的对策与措施。  相似文献   
258.
尹明  李晓燕 《遥感学报》2012,16(S1):6-9
无地面控制点条件下, 卫星摄影测量研究与工程实践是世界各国在该领域中所面临的研究难点之一。本文介绍了在无地面控制条件下光学卫星摄影测量的研究发展和工程实践历程, 并对中国“天绘一号”卫星获取的影像实测结果进行分析, 结果表明, 中国在无地面控制条件下的卫星摄影测量研究与工程实践已居于国际领先地位。  相似文献   
259.
中国汽车空调行业HFC-134a需求和排放预测   总被引:1,自引:0,他引:1       下载免费PDF全文
 近年来HFC-134a作为中国汽车空调行业CFC-12制冷剂最主要的替代品,其消费量增长迅速,是中国消费量最大的HFCs(氢氟烃类物质)。以2005年为基线,通过制冷剂替代、技术进步、熟练操作和政策控制等情景假设,预测了中国汽车空调行业HFC-134a的需求量及排放量。结果表明:到2010和2015年,汽车空调HFC-134a的消费量将分别接近2.0万和3.5万t,排放量将分别接近1.6万和3.0万t,约折合排放21.0 和39.0 Mt CO2当量。上述排放相对基线情景(即维持当前政策措施和不开展回收活动),2010年和2015年减排温室气体分别为6.7 和13.0 Mt CO2当量。  相似文献   
260.
对信阳市南湾水库渔业气象服务效益调查分析结果表明:在亲鱼培育、种苗繁殖、苗种培育、成鱼养殖、捕捞等主要生产阶段,成鱼养殖阶段服务效益最大,为21.98万元;繁殖、亲鱼培育阶段服务效益占该阶段渔业总产值的比例分别列第一和第二,说明这两个生产阶段气象服务尤为重要.由于对渔业气象服务还不够重视,加之还缺乏渔业与气象条件关系的研究,目前渔业气象服务层次较低,渔业气象服务效益贡献率也较低.  相似文献   
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