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131.
在ERDAS软件中,通过数据导入、波段合成、几何校正、图像增强等处理,得到高质量的昆明地区2000年和2004年两时相遥感图像。用AOI种子扩展工具在图像上生成昆明市城区范围,做出城区扩展动态叠加图,并用测量工具测量统计得到:2004年昆明市城区面积已达180平方千米,而在2000年图像中这个数仅为130平方千米。在这四年内昆明市城区以年增长率1.64%的速度迅速扩展。且对比得出昆明市城区的扩展趋势,即城区主要向东南呈贡县方向,和东北金殿、松华坝水库方向发展,为城市土地资源的规划和治理提供依据。 相似文献
132.
王盘兴 《Acta Meteorologica Sinica》1992,(3)
Limitations of difference maps showing circulation anomalies are analyzed, and the definition of the local patternanalogue coefficient (LPAC) is given together with the procedure for constructing such a map, followed by an exampleillustrating its useful application in circulation anomaly. 相似文献
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134.
针对依兰煤田钻探施工中出现的钻孔缩径挤夹钻具事故,提出产生事故的根本原因不是因岩层本身膨胀所致,而是由于某种岩层裂隙发育,渗透性良好,吸水性强,使钻孔孔壁泥皮迅速增厚所致,并提出预防事故的具体措施。 相似文献
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文章回顾20世纪以来,在广西发现的重要古人类化石和文化遗物,包括4个巨猿化石地点、13个晚期智人化石地点以及一系列旧石器.对柳江人遗址等的地层和年代学进行了综合研究,对国际学术界关于现代人起源的"多地区连续演化说"将提供强有力的证据;百色盆地旧石器的综合研究,将对恢复早中更新世的环境和早期人类迁徙、扩散的模式,有着深远的意义. 相似文献
137.
With the availability of spatially distributed data, distributed hydrologic models are increasingly used for simulation of spatially varied hydrologic processes to understand and manage natural and human activities that affect watershed systems. Multi‐objective optimization methods have been applied to calibrate distributed hydrologic models using observed data from multiple sites. As the time consumed by running these complex models is increasing substantially, selecting efficient and effective multi‐objective optimization algorithms is becoming a nontrivial issue. In this study, we evaluated a multi‐algorithm, genetically adaptive multi‐objective method (AMALGAM) for multi‐site calibration of a distributed hydrologic model—Soil and Water Assessment Tool (SWAT), and compared its performance with two widely used evolutionary multi‐objective optimization (EMO) algorithms (i.e. Strength Pareto Evolutionary Algorithm 2 (SPEA2) and Non‐dominated Sorted Genetic Algorithm II (NSGA‐II)). In order to provide insights into each method's overall performance, these three methods were tested in four watersheds with various characteristics. The test results indicate that the AMALGAM can consistently provide competitive or superior results compared with the other two methods. The multi‐method search framework of AMALGAM, which can flexibly and adaptively utilize multiple optimization algorithms, makes it a promising tool for multi‐site calibration of the distributed SWAT. For practical use of AMALGAM, it is suggested to implement this method in multiple trials with relatively small number of model runs rather than run it once with long iterations. In addition, incorporating different multi‐objective optimization algorithms and multi‐mode search operators into AMALGAM deserves further research. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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自庆深气田徐深1井取得深层天然气勘探重大突破以来,大庆油田步入了油气勘探开发并举阶段。2004—2010年完成123口井,平均井深4118 m、钻井周期141 d,钻井技术水平较低。虽然开展提速技术攻关取得一定效果,但仍然不能满足天然气快速增储上产的需求,还存在着固井后井口带压问题,急需深入开展钻完井技术攻关。自2011年起,借鉴国内外深层提速技术成果,分开次、分层段针对岩性特点制定提速对策,通过优化井身结构、优选高效PDC钻头、实验并自研液动旋冲和涡轮等新型提速工具,大幅度提高了深井钻井技术水平,2011—2013年完成19口井,平均井深4075 m、同比缩短钻井周期48.6 d;针对井口带压问题,综合分析其产生因素,开展系列技术研究,形成了防气窜固井配套技术,为深层天然气快速增储上产提供了支持和保障。 相似文献
140.
Groundwater in contact with ore deposits may acquire a chemical composition that could be used as a guide for exploration. Eight well-water samples are collected from a known uranium-mineralized area near Abu Zenima, west central Sinai to examine the applicability of using the hydrogeochemical technique in the search for uranium mineralization in similar arid areas. The analytical chemical data of the ground water is compared with ground radiometric measurements. The obtained results indicate that groundwater affected by uranium mineralization has a specific relativity of major anions expressed essentially as SO4>Cl>HCO3 and to a lesser extent as Cl>SO4>HCO3, associated as a rule with low magnesium content. This association constitutes a signature of uranium mineralization on the composition of groundwater in west central Sinai and could be used as an important exploration guide in the search for uranium deposits in similar areas. Anomalies in Ni, Fe, Zn and Cr and other pathfinder elements in groundwater can furnish geochemical guides to uranium ores. The immobile trace element anomalies, including Zn, Ni and Fe are strongly distributed near the orebody; whereas the relatively mobile trace elements, including Co, U, V and Cr, constitute the dispersion haloes away from the orebody. A new hydrogeochemical discrimination diagram is constructed to be used as a quick and cost effective exploration tool in the search for uranium occurrences in environmentally similar arid areas. Based on the obtained results, a new site for uranium occurrence, west of W. Baba, is delineated and recommended for future detailed geological and geochemical surveying. 相似文献