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61.
长期的地震实践表明,地下流体与地震活动有密切的关系,特别是在地震短期阶段,地震前兆中流体异常表现的最为明显,并且数量最多.由于在地震孕育过程中,能够引起浅层流体异常的动力源机制比较复杂,异常变化形态也复杂多样,这对于有效分析异常产生的机理造成了很大困难.本项研究工作,通过中国大陆和华北、西北、西南等分区研究,认为可以将这些复杂的异常现象归纳为较易识别的转折型(复合型)和单一型两类异常类型,并提出了这两类前兆异常类型的综合特点.  相似文献   
62.
曹文凯  禹海峰  师庆广 《地下水》2004,26(2):134-136
本文分析了岩浆岩侵入中岩脉、岩盘对围岩富水性的影响及富水层的电法辨认,提出了在不同侵入的围岩地层内用电法寻找地下水的方法.  相似文献   
63.
曹文京  郭延杰  孙兰华 《地下水》2004,26(2):115-116
地下水是聊城市重要的而且是主要的水资源,近年来,地下水的开采和补源引起了人们的广泛关注.本文拟对地下淡水资源的时空分布、运动规律、地下水资源计算和评价及聊城市地下水开发利用问题进行一些探讨,对于引黄(河)灌区合理引用黄河水和开采地下水具有重要的指导作用和应用价值.  相似文献   
64.
曹小虎 《地下水》2004,26(4):300-302
地下水在山西国民经济发展中的地位极为重要,多年不合理的开采已形成了严重超采局面,并引起了一系列生态环境恶化问题.本文通过对山西地下水开发引起的生态环境恶化状况分析,阐述了合理开发利用地下水资源的必要性.  相似文献   
65.
Three soil profiles were selected in the Ejina Oasis, northwest China, to determine water content profiles and evolution of soil moisture potentials in the unsaturated zone within the arid area. The total soil moisture potentials have been monitored for about 3 months in 2001 at different depths in the soil profiles. The occurrence and movement of water in the unsaturated zone was analyzed using the zero flux plane (ZFP) method. It is shown that convergent ZFPs and divergent ZFPs may occur at depths between 0.5 and 3.0 m, and that the depth of the ZFPs was controlled by the root zone of plants growing on the land surface. Profiles of the total soil moisture potentials were observed to be coincident with those of the water contents at the three experimental sites. The total soil moisture potential showed a slight increasing trend and the ZFPs tend to vanish from summer to winter as the water extraction by roots decreased. Evapotranspiration through vegetation has an important bearing on the water content and the total potential in the unsaturated zone.  相似文献   
66.
This paper presents the detailed results and analyses on the ecological footprints and bio-capacities of the individual cities and the province as a whole for the year 2001, providing a clear picture of sustainability for the province. Results show that the ecological footprints of most cities in Liaoning exceeded their respective bio-capacities, incurring high ecological deficits. The ecological deficit of the province as a whole was 1.31 ha/cap. Those cities with resources extraction and/or primary material-making as their major industries constitute the "ecologically black band", whose ecological deficits ranged from 2.45 to 5.23 ha/cap, the highest of all cities in the province. Fossil energy consumption was the major source of footprint amounting to 1.63 ha/cap at the provincial level, taking up 67.3% of the total. For cropland, modest ecological surpluses occurred in Jinzhou, Tieling, Huludao, and Panjin while modest ecological deficits in Dalian, Benxi, Fushun, and Dandong, resulting in an overall surplus for the province. Liaoning had a certain level of surplus in fishing ground (water area), mainly distributed in the coastal cities of Dalian, Panjin, Huludao, Yingkou, Jinzhou, and Dandong. Most cities had a small ecological deficit in pasture and all had a small ecological surplus in forest. The eco-efficiency, expressed as GDP value per hectare of footprint, exhibits high variations among the cities, with the highest (Shenyang) more than 10 times the lowest (Fuxin). Cities with manufacture, high-tech, and better developed service industries had high eco-efficiency, while those with resources extraction, primary material-making, and less developed service industries had low eco-efficiency. Based on the components and geographical distribution of ecological footprint, strategic policy implications are outlined for Liaoning's development toward a sustainable future.  相似文献   
67.
68.
由于OSSMO 2004版地面测报业务软件中抄录报表风向不太方便,故长治县气象局自行设计了自动风向角度和方位的转换程序。本程序用OBJECT PASCAL语言编写,在DELPHI中实现,采用Microsoft.Jet.OLEDB.4.0数据库引擎及ADO的方式操作数据库。  相似文献   
69.
The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the variation of the AO index and the leading principal component time series of the summer rainfall in East Asia, The rainfall anomaly changed from below normal to above normal in central China, the southern part of northeastern China and the Korean peninsula around 1978. However,the opposite interdecadal variation was found in the rainfall anomaly in North China and South China.The interdecadal variation of summer rainfall is associated with the weakening of the East Asia summer monsoon circulation. It is indicated that the interdecadal variation of the AO exerts an influence on the weakening of the monsoon circulation. The recent trend in the AO toward its high-index polarity during the past two decades plays important roles in the land-sea contrast anomalies and wintertime precipitation anomaly. The mid- and high-latitude regions of the Asian continent are warming, while the low-latitude regions are cooling in winter and spring along with the AO entering its high-index polarity after the late 1970s. In the meantime, the precipitation over the Tibetan Plateau and South China is excessive, implying an increase of soil moisture. The cooling tendency of the land in the southern part of Asia will persist until summer because of the memory of soil moisture. So the warming of the Asian continent is relatively slow in summer. Moreover, the Indian Ocean and Pacific Ocean which are located southward and eastward of the Asian land, are warming from winter to summer. This suggests that the contrast between the land and sea is decreased in summer. The interdecadal decrease of the land-sea heat contrast finally leads to the weakening of the East Asia summer monsoon circulation.  相似文献   
70.
Continent-continent collision is the most important driving mechanism for the occurrence of various geological processes in the continental lithosphere. How to recognize and determine continent-continent collision,especially its four-dimensional temporal-spatial evolution, is a subject that geological communities have long been concerned about and studied. Continent-continent collision is mainly manifested by strong underthrnsting (subduction) of the underlying block along an intracontinental subduction zone and continuous obduction (thrusting propagation) of the overlying block along the intracontinental subduction zone, the occurrence of a basin-range tectonic framework in a direction perpendicular to the subduction zone and the flexure and disruption of the Moho. On the basis of numerical modeling, the authors discuss in detail the couplings between various amounts and rates of displacement caused by basin subsidence, mountain uplift and Moho updoming and downflexure during obduction (thrusting propagation) and subduction and the migration pattern of basin centers. They are probably indications or criteria for judgment or determination of continent-continent collision.  相似文献   
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