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1.
In rapid socio-economic development,the process of concentration and dispersal of various elements tends to be more dramatic,tremendously influencing the shaping and transformation of the space in metropolitan area.Survey of spatial concentration and decentralization has thus become a basic method in examining metropolitan spatial evolution.In this research,three elements were selected as the essential indicators of the process:demographic density distribu-tion,employment density distribution and business office location.Performance of these elements in Nanjing City was exam-ined historically.As Nanjing City could be regarded as a representative of metropolitan areas in China,its situation large-ly suggestes the general characteristics in similar areas of China.Hence based on the investigation of Nanjing City,four general implications were highlighted.First ,metropolitan areas in China are in a violent process and shift of spatial concentra-tion and decentralization.Second,from now to at least the near future,concentration will continue to be the central fea-ture.Third,the landscape of metropolitan areas basically exhibits a dual structure character.The gap in environmental and ecological qualities among different districts will continue for a long time.Fourth,Central Business District (CBD) is playing an important role in helping to convert the traditionally single-centered city structure into a polycentric one.  相似文献   
2.
Mobile Agent技术是一门新兴的技术,具有移动性、智能性和异步计算的特点,已成为计算机网络和分布式系统最具活力的发展方向.现对Mobile Agent的概念、系统结构及其关键技术进行了分析和探讨.  相似文献   
3.
西南矿区山体崩塌成因机制分析及防治对策   总被引:1,自引:0,他引:1  
西南地区的矿区具有相似的地理、地质环境,通过四川芙蓉煤矿白岩崩塌的典型实例,对西南矿区山体崩塌的成灾环境进行调查研究,揭示了西南矿区山体崩塌的成因机制,并简要提出了对该煤矿开发与综合治理建议,指出了加强防治工作的紧迫性,强调开展系统工程防灾的重要性,并为该煤矿解决正常采掘接替及工作面的布置问题作出了科学的指导.  相似文献   
4.
In recent years, many coal-producing countries have paid great attention to the land subsidence causedby coal cutting. In China, because of the dense population in coalfield areas, the land subsidence hazard is more seri-ous. After a brief analysis on the mechanism of land subsidence, this paper gives a comprehensive and systematical ac-count on all kinds of hazards caused by the land subsidence in China. The study shows that land subsidence has endan-gered land, buildings, traffic and communication lines, dykes and dams. It also causes damage to ecological and socialenvironment. In order to lessen the hazard of land subsidence, preventive measures should be taken to reduce the col-lapse amount, such as extraction with stowing, banded mining system, succession and coordination mining system, orhigh-pressure mudflow between rock strata. Measures of reinforcing or moving certain buildings should also be taken toreduce the destructive degree. In order to harness the subsidence land and bring them under control for fanning, mea-sures should be taken such as filling with spoil or fine breeze, excavating the deeper and covering the shallower land.  相似文献   
5.
Boli basin, between Yishu fracture belt and Dunmi fracture belt, is the biggest Mesozoic coal basin in the east of Heilongjiang Province. Now it is a fault - fold remnant basin. The basin' s shape is generally consistent with the whole distribution of the cover folds, an arc protruding southwards. The basement of the basin can be divided into three fault blocks or structural units. The formation and evoluation of the basin in Mesozoic was determined by the basement fault blocks' displacement features rusulted from by the movement of the edge faults and the main basement faults.  相似文献   
6.
Kenai, located on the west coast of the Kenai Peninsula, Alaska, subsided during the great earthquake of AD 1964. Regional land subsidence is recorded within the estuarine stratigraphy as peat overlain by tidal silt and clay. Reconstructions using quantitative diatom transfer functions estimate co‐seismic subsidence (relative sea‐level rise) between 0.28±0.28 m and 0.70±0.28 m followed by rapid post‐seismic recovery. Stratigraphy records an earlier co‐seismic event as a second peat‐silt couplet, dated to ~1500–1400 cal. yr BP with 1.14±0.28 m subsidence. Two decimetre‐scale relative sea‐level rises are more likely the result of glacio‐isostatic responses to late Holocene and Little Ice Age glacier expansions rather than to co‐seismic subsidence during great earthquakes. Comparison with other sites around Cook Inlet, at Girdwood and Ocean View, helps in constructing regional patterns of land‐level change associated with three great earthquakes, AD 1964, ~950–850 cal. yr BP and ~1500–1400 cal. yr BP. Each earthquake has a different spatial pattern of co‐seismic subsidence which indicates that assessment of seismic hazard in southern Alaska requires an understanding of multiple great earthquakes, not only the most recent. All three earthquakes show a pre‐seismic phase of gradual land subsidence that marked the end of relative land uplift caused by inter‐seismic strain accumulation. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
7.
基于Windows消息机制的人机交互的研究与应用   总被引:1,自引:0,他引:1  
结合实例着重介绍了如何通过串行通讯利用Windows的消息机制来解决目前工业设备控制中人机交互的模拟问题,并对这两种技术进行了详细的论述.  相似文献   
8.
古侵蚀沉积间断面型金矿是桂西的主要金矿床类型。文章着重分析该类型金矿成矿地质条件 ,论述矿床成因及成矿机理 ,认为此类型金矿易采易冶 ,经济效益显著 ,建议加大开发力度。  相似文献   
9.
10.
商丹断裂带是北秦岭加里东造山带与中秦岭海西造山带的分界断裂,由韧性剪切应变带、逆冲推覆构造带、地堑断陷带及其所夹持的岩块、岩片、构造岩、褶曲等多种地质体组合成复杂的断裂带。其演化历史至少经历晋宁期俯冲、加里东期碰撞、海西—印支期陆内俯冲、燕山期滑脱推覆和喜山期地堑断陷的复杂演化过程而形成今日所见的复杂断裂构造。  相似文献   
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