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191.
Risk assessment of rainstorm and flood disasters in China between 2004 and 2009 based on gray fixed weight cluster analysis 总被引:3,自引:0,他引:3
Rainstorm and flood disasters frequently occur in China, causing heavy losses for people’s lives and property and reducing the capability of sustainable development of the national and local economy. In this study, the risks of the rainstorm and flood disasters are assessed for the Chinese mainland, excluding Hong Kong, Macao, and Taiwan and also employ the historical data of seven indicators, including the affected area of crops, the affected population, the direct economic loss, and etc., from 2004 to 2009. Based on the large 1,302 historical sample data, the impact of rainstorm and flood disasters were analyzed using the methodology of gray fixed weight cluster analysis according to disaster losses, which were divided into the three gray classes of high, medium, and low. The regional differences of the risk assessment of the rainstorm and flood disasters are discussed, and the dynamical risk zoning map is conducted. The results show a consistent conclusion with the actual losses of rainstorm and flood disasters over each administrative district, which can provide more scientific evidence for the relevant departments of disaster prevention and mitigation. 相似文献
192.
锚索的预应力损失在工程建设中不可忽视,工程的场地环境条件成为影响锚索预应力损失的主因。饱和粉细砂层较其他地质条件更为复杂敏感,更易引起锚索预应力值的损失。通过对廊坊市某深基坑工程锚索预应力值的实时监测,结合工程环境,分析饱和粉细砂层中造成锚索预应力值变化的原因。结果表明,施工过程、张拉过程以及环境因素都影响锚索预应力的变化,其中开挖过程的影响最明显,预应力值的变化率最大值达79.1%;瞬时卸载造成预应力值22.8%59.2%的损失。对饱和粉细砂层中锚索预应力变化规律的研究分析结论可为类似地质环境的工程建设提供经验。 相似文献
193.
Mobilization and redistribution of elements in soils developed from extreme weathering basalt on Hainan Island 总被引:1,自引:0,他引:1
Major, trace and organic elements of a South China were reported to investigate elements laterite profile developed on Neogene basalt on Hainan Island, mobilization and redistribution in tropical regions. The results indicate that strong acid environment and organic matter (OM) can remarkably improve the transfer of insoluble elements. Among all the elements, Th is the least mobile. As for the general conservative elements during incipient chemical weathering, such as Ti, Zr, Hf and Nb, the removals are up to 30%-40% in the upper profile. And for Fe, A1, Cu and Ni, that tend to be combined with secondary minerals and to be retained in temperate zone, they are re- moved from the upper profile, transferred downwards, and then precipitated in the lower profile. In addition, atmos- pheric inputs, including sea salt aerosols and dust, have a profound effect on the budgets of elements that are susceptible to leaching losses (e.g. K, Na and Sr). Excluding the possibilities of groundwater and erosion, the remarkable increase of K, Na and Sr concentrations in the upper profile, together with dramatically upward increasing trends of the percentage changes of Sr/Th, K/Th and Na/Th ratios, show that atmospheric inputs, especially sea salt aerosols, contribute much extraneous seawater derived elements, such as K, Na and Sr to the soils. The overall elemental be- haviors in this profile suggest that organic matter and atmospheric inputs play a very important role in the mobiliza- tion and redistribution of elements during extreme weathering in tropical regions. 相似文献
194.
XU Li WU Xiaochun Lü Junchang JIA Songhai ZHANG Jiming PU Hanyong ZHANG Xingliao 《《地质学报》英文版》2014,88(4):1041-1050
Funiusaurus luanchuanensis gen. et sp. nov. was described on the basis of an incomplete skull from the Upper Cretaceous Qiupa Formation of the Tantou Basin in Luanehuan County, Henan Province. It is the second representative of lizards known from Luanchuan and adds a new member to the Luanchuan Fauna. F. luanchuanensis is a small-sized lizard and systematically assigned to the Polyglyphanodontidae of the Teiioidea because of the presence of a caniniform tooth and an elongate posterior process of the postorbital. It is distinctive in that the heterodont dentition bears 19 teeth in both the upper and lower jaws, the 3^rd maxillary tooth is large and caniniform, the post-caniniform teeth in maxilla and those posterior to the 3^rd dentary tooth are chisel-like in lateral view, the prefrontal possesses a fossa on its lateral surface, the postorbital with an extremely elongate posterior process and the well-developed retroarticular process has a deep fossa on its dorsal surface. In phylogeny, our analysis suggests a close relationship of Funiusaurus to the large-sized Tianyusaurus from the same basin within the Tuberocephalosaurinae. The discovery of Funiusaurus is significant in confirming the status of the Tuberocephalosaurinae, which includes a group of the Asian members of the Polyglyphanodontidae only. 相似文献
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196.
The research area is located in the western part of Sichuan basin as a Yangtze ecotope of Cathaysian Tethyan area. It is dominated by benthic fauna, including brachiopods, Fusulinids, corals, bivalves, foraminifers, ammonites, bryozoans,Crinoids and pleopods which are less common with traces of trilobites, stromatoporas, nautilus and sporopollens seen in one or two areas,which are obviously controlled by sedimentary environments and in accordance with sedimentary facies.Through the analysis of fossils and research on burial characteristics from middle Permian middleTriassic, based on the combination of the feature of fossils in time and space, seventeen communities are recognized, the coposition, construction and palaeoenvironment of each community are expounded. Study shows that different ecological type biocoenose are distributed in different locations, which are mainly represented by sessile benthic community in the main research area, composed of Mianzhu, Mianyang, Deyang and Santai and nektonic community in marginal areas in the research area subdivided into two parts: Areas around Guangyuan-Nanjiang-Tongjiang, located at the margins in the northeast of the research area, and areas around Wenchuan-Maoxian-Dayidafeishui situated at the western borders of the research area. According to the combination of communities with sedimentary characteristics,six kinds of biofacies have been recognized and described in the study area and biofacies pattern are established. Category,ecotype, typical community and sedimentary facies of each biofacies are elucidated in this paper. The subdivision and analysis of community are meaningful for the studies of paleoenvironment ,paleogeography and their evolutions,The research of biaofacies is important for the recovery of paleobiogeography and paleoplate tectonic characteristics. 相似文献
197.
198.
根据宜昌站、汉口站和大通站的径流量数据,运用M-K检验和小波分析等方法,对1900年以来长江流域径流量的趋势和周期变化进行分析,探究径流量变化对厄尔尼诺?南方涛动(ENSO)和太平洋年代际振荡(PDO)的响应。结果表明:1900 年以来长江流域径流量呈显著的减少趋势,并具有2~8 a的年际周期变化和14~17 a的年代际周期变化。流域径流量与ENSO具有相同的2~8 a周期变化,在El Ni?o发生期,径流量较低,在La Ni?a发生期,径流量较高。14~17 a的周期变化与PDO相关,在暖位相期径流量偏少,在冷位相期径流量偏多。PDO影响着ENSO和径流量之间的相关性,在暖位相期,El Ni?o对径流量的影响增强,在冷位相期,La Ni?a对径流量的影响增强。因此,在分析和预测流域径流量长时间尺度上的变化时要综合考虑ENSO和PDO的影响。 相似文献
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200.