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Received date: -- Revised date: -- Foundation item: Under the auspices of the National Natural Science Foundation of China 《地理学报(英文版)》2000,(3)
1 Introduction1.1 Introduction to Liaocheng PrefectureLiaocheng
Prefecture lies in northwest of Shandong Province and slightly north to the center of the Huang-Huai-Hai Plain with latitudes between 35(47'N and 37(02'N and longitudes between 115(16'E and 116(32'E. Administratively, it consists of two cities (Liaocheng and Linqing) and six counties (Yanggu, Shenxian, Chiping, Dong'e, Guanxian and Gaotang). It covers a total area of 8590 km2 with a maximum distance of 114 km from eas… 相似文献
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A Simple Monte Carlo Method for Locating the Three-dimensional Critical Slip Surface of a Slope 总被引:2,自引:0,他引:2
XIE Mowen Institute of Environmental Systems Kyushu University Hakozaki -- Higashi Ku Fukuok Japan College of Resource Engineering the University of Science Technology Beijing Xueyuan Ro Haidian District Beijing China 《《地质学报》英文版》2004,78(6):1258-1266
Based on the assumption of the plain-strain problem, various optimization or random search methods have been developed for locating the critical slip surfaces in slope-stability analysis, but none of such methods is applicable to the 3D case. In this paper, a simple Monte Carlo random simulation method is proposed to identify the 3D critical slip surface. Assuming the initial slip to be the lower part of a slip ellipsoid, the 3D critical slip surface is located by means of a minimized 3D safety factor. A column-based 3D slope stability analysis model is used to calculate this factor. In this study, some practical cases of known minimum safety factors and critical slip surfaces in 2D analysis are extended to 3D slope problems to locate the critical slip surfaces. Compared with the 2D result, the resulting 3D critical slip surface has no apparent difference in terms of only cross section, but the associated 3D safety factor is definitely higher. 相似文献
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Current situation and trend of arable land change in China 总被引:1,自引:0,他引:1
IntroductionAlmost all the developing countries have experienced the decrease of cultivated land in the process of population growth, economic development and urbanization. The situation is more serious in China because of the huge amount of population and relative limited arable land. From 1986 to 1995, the cultivated land has decreased nearly 7 million hectares, the amount of annual decrease is 0.7 million hectares in China according to the available statistical data. But the real situation… 相似文献
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Protective and treatment measures against major harmful organisms in cotton-growing belt of Xinjiang
Received date: -- Foundation item: Supported by Light of Western Regions Project Key Project of CAS Integrated Demonstration Project for Sustainable Development of Cotton in Xinjiang with High Quality High Yield Technique LU Zhaozhi CHEN 《地理学报(英文版)》2000,(3)
1 Harmful Organisms in Xinjiang Cotton-Growing BeltThe harmful organisms in Xinjiang cotton-growing belt are mainly diseases, insects and weeds. The diseases include Verticillium albo-atrum, cotton-root decaying disease and cotton-boll decaying disease, while the harmful insects include cotton aphids (Aphis gosspii), cotton mites, cotton boll-worms (Heliothis armigera), cotton thrips (Thrips. sp), Lygus pratersis and cutworms. Their harmful effects vary in different places but all of them … 相似文献
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位于中国西南的小江 (Xiaojiang)断裂带作为康定 (Kangding)断裂带的南段 ,在青藏块体向SE方向挤出的过程中起着重要的作用。根据断错地貌以及这些断错地貌14 C年代或热释光年代 ,推算了小江断裂带第四纪晚期的左旋走滑速率。小江断裂带可以分为 3段 ,其中段由平行的两条断层组成。西支断层和东支断层的左旋走滑速率分别为 7.0~ 9.0mm/ yr和 6 .0~ 7.5mm/yr。简单相加 ,就可以推算出小江 (Xiaojiang)断裂带总的左旋走滑速率为 13 0~ 16 5mm/ yr,与康定断裂带北段的鲜水河 (Xianshuihe)断层的走滑速率大致相当 ,约等于康定 (Kangding)断裂带中段的安宁河 (Anninghe)断层及则木河 (Zemuhe)断层的两倍。这个结果可能暗示了在康定断裂带中段 ,可能存在着其他断层以解消另外一半的滑动速率。最有可能的断层是位于康定断裂带中段以东几十公里的普雄河 -布拖 (Puxionghe Butuo)断层 相似文献
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We report here the occurrence of pink sapphires in association with a variety of gemstones from the Trivandrum Granulite Block south of the Achankovil Shear Zone in southern India. The mineralization is associated with pegmatites or veins emplaced within granulite facies aluminous supracrustals. The sapphires show near-pure A1,0, composition (98.43-99.48 wt.%) with traces of Cr, O, (0.02-0.12 wt.%) and FeO (0.01-0.12 wt.%). The available radiometric age of 513-2 Ma for gem quality zircon associated with pink sapphire in the Melankode locality confirms that the mineralization is of late Pan-African age. Pink sapphires have been widely reported from a number of localities in southern Madagascar including Betroka, Illakaka, Antranondambo and Ambossary. Sapphires of various hues also occur in the Ratnapura gem district in the southwestern part of Sri Lanka. The pink sapphire occurrences in southern Madagascar and southern Kerala provide strong evidence for India-Madagascar juxtaposition in the Gondwana assembly with the Ranotsara Shear Zone in southern Madagascar extending into the Achankovil Shear Zone in southern India. 相似文献
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Received date: -- Foundation item: The national key research project: Field water balance its regulation techniques water potential productivity its proper exploitation in typical dryland farming areas of northern China for the Ninth Five 《地理学报(英文版)》2000,(3)
1 IntroductionIn natural conditions, field water surplus or deficit is different between field water requirement and field water supply by nature. Field water requirement can be expressed either as potential field evapotranspiration or as crop water requirement. Potential field evapotranspiration is also called reference crop evapotranspiration which is defined as "the rate of evapotranspiration from an extensive surface of 8 to 15 cm tall, green grass cover of uniform height, actively growing… 相似文献
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1 IntroductionUrban fringe refers to the zone surrounding the built urban area, or the transitional zone between city and suburbs. Located on the fringe of the built urban external area, urban fringe is notably featured as a linking place of city and country, and as a combining growth of urban-rural economy. Presently, most of the large and medium-sized cities in China are at the stage of active construction where central areas are keeping step with surrounding areas. Meanwhile, fringe constr… 相似文献
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