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Developmetn stage threshold of watershed Landforms in Loess Plateau and separation of erosion mechanism

Journal of geographical Sciences 2002年第1期12卷 81-90页

作者： LU Zhong-chen1, CHEN Shao-feng2,YUAN Bao-yin3,CHEN Hao4 (1.Eco-Environment Research Center,CAS,Beijing 100085,China 2.institute of Policy andManagement Science,CAS,Beijing 100080,China 3.institute of Geology,CAS,Beijing1000029,China 4.institute of geograp

Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by *** in the 1970s, the quantitative research on watershed landform development stage has come true. Davis proposed a three-stage model on landform evolution: young, mature and old stages. Thereafter Strahler quantified this model by hypsometric analysis method. The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage, because of the uncertainty on stage delimitation. To meet this shortcoming, this paper presents an integral erosion value method. A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method. The result shows that gullied loessial hilly area is at the mature stage, and gullied loessial tableland area is at the young stage. It is estimated that from the point of erosion related sediment yield, natural erosion accounts for 70% of the total erosion amount, and artificial accelerating erosion is 30%. Therefore soil and water conservation is very crucial for the Loess Plateau.

关键词： landform development stage hypsometric analysis method integral erosion value natural erosion artificial accelerating erosion

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A study on sustainable development capacity of China's coastal areas using indices dimension reduction method

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Journal of geographical Sciences 2000年第4期10卷 28-36页

作者： WANG Li-ming, YANG Yan-feng, MAO Han-ying, CHEN Wei-min (institute of geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China) 中科院地理科学与资源所北京

Sustainable Development Capacity (SDC) is a comprehensive concept. In order to obtain a relatively objective evaluation of it, many indices of various aspects are often used in assessing index systems. However, the overlapping information of indices is a frequent source deviating the result from the truth. In this paper, 48 indices are selected as original variables in assessing SDC of China's coastal areas. The mathematical method of dimension reducing treatment is used for eliminating the overlapping information in 48 variables. Five new comprehensive indices are extracted bearing efficient messages of original indices. On the base of new indices values, the sequencing of 12 coastal areas SDC is gained, and five patterns of sustainable development regions are sorted. Then, the leading factors and their relations of SDC in these patterns are analyzed. The gains of research are discussed in the end.

关键词： sustainable development capacity dimension reduction China's coastal areas

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3S技术在铁路工务系统中的应用

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铁路计算机应用 2004年第12期13卷 18-20页

作者：黄彬武郁松柳州铁路局科学研究所柳州545007 中南大学信息工程学院长沙430075

3S技术在各行各业中得到了广泛的应用,并产生了很大的社会和经济价值。从3S技术的特点出发,结合铁路工务系统的实际情况,提出了3S技术在铁路工务系统中应用的方向。

关键词： 3S 铁路工务系统应用地理信息系统

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