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231.
基于可靠度和灵敏度的结构局部地震易损性分析   总被引:8,自引:0,他引:8  
结构的地震易损性分析是结构地震风险分析的核心内容,传统的方法主要是分析结构的整体地震易损性。提出了结构局部地震易损性的概念,通过构造结构局部性能指标与其参数之间的一个新的功能函数,给出了局部地震易损性的可靠度表达式;根据可靠性灵敏度的概念,提出了构造结构局部性能指标概率密度函数的新方法,并详细推导了结构可靠指标对局部性能指标参数的灵敏度表达式。算例表明,所提方法可极大地提高结构地震易损性分析的计算效率。  相似文献   
232.
不同农田生态系统土壤碳库管理指数的研究   总被引:20,自引:1,他引:20  
用高锰酸钾氧化法讨论了土壤活性碳库和碳库管理指数(CPMI)。结果表明:不同农田土壤活性碳含量为049~499mg/g、CPMI为516~165。不同施肥处理对红壤CPMI的影响为绿肥(GM)>厩肥(FYM)>FYM+NPK>参考(REF)>NPK>对照(CK);对水稻土为:稻草(RSC)>FYM>FYM+NPK>REF>NPK>CK。黄棕壤GM、FYM和FYM+NPK处理的CPMI分别比REF提高了50%、459%和219%,NPK和CK下降了6%和381%。潮土施肥10年的CPMI与施肥5年相比,FYM和FYM+NPK提高了284%和197%,而NPK和CK下降87%和179%。相关分析表明,CPMI与土壤全氮、全磷、碱解氮、速效磷、速效钾、pH相关或极相关。这表明CPMI可灵敏地反映农业生产措施对土壤碳库的影响  相似文献   
233.
用尼梅罗(Nemerow)污染指数评价地表水营养状况的探讨   总被引:1,自引:0,他引:1  
引用尼梅罗指数公式,通过对其适当改造来评价水体的营养状态水平。论述了该方法的可行性和现实性、项目选择的依据及实际应用,实践证明,与传统评价方法相比,本方法是可行与可靠的。  相似文献   
234.
We analyzed the possible effects of grazing management and future climate change on carbon (C) stocks in soils of northern Patagonian shrublands. To this aim, we coupled the outputs of three (HadCM3, CSIRO Mk2, and CCSR/NIES) global climate models to the CENTURY (v5.3) model of terrestrial C balance. The CENTURY model was initialized with long-term field data on local biome physiognomy, seasonal phenologic trends, and prevailing land-management systems and was validated with recent sequences of 1-km Normalized Difference Vegetation Index (MODIS-Terra) images and soil C data. In the tested scenarios, the predicted climate changes would result in increased total C in soil organic matter (SOMTC). Maximum SOMTC under changed climate forcing would not differ significantly from that expected under baseline conditions (8 kg m−2). A decrease in grazing intensity would result in SOMTC increases of 11% to 12% even if climate changes did not occur. Climate change would account for SOMTC increases of 5% to 6%.  相似文献   
235.
Promoting occupational safety and health in Hong Kong,Special Administrative Region of China is an important and ongoing mission. As the major organization with statutory responsibilities,the Occupational Safety and Health Council understand the importance to strengthen and cultivate our safety culture. It is widely believed that numbers of occupational related diseases and injuries could be prevented with the improvement of the awareness and attitudes of the employees and the public. Therefore,a comprehensive and in-depth study to monitor the occupational health and safety level and status of the community and working population is needed. Objectives: Our Council has developed the Occupational Safety Culture Index ( OSCI) to measure the current level of community and workplace safety and health awareness,knowledge and attitude. Benchmarking measures of the key safety performance indicators are to be derived thereof. Methods: A territory-wide random telephone survey was conducted to assess the community and employees’awareness,attitude and knowledge in 2008. A structured questionnaire was designed with the content validity and reliability assessed before the survey administration. A series of quality control approaches were also applied to assure the quality of the fieldwork and the reliability of the data. Results: 1,531 eligible participants’data were collected and computed into 2 types of composite indices,Occupational Safety Culture Index ( Community) ( OSCIC) and Occupational Safety Culture Index (Workplace) (OSCIW) . With the maximum score of index at 100,the overall score of OSCIC is 66. 9 and the OSCIW is 61. 3 in Hong Kong. Achievements: OSCI served as an effective management tool to measure the safety culture in Hong Kong. With a representative sample and high quality study control and validated assessment approaches,the OSCI and the sub-indices are reliable indicators to assess the effectiveness of safety culture enhancement strategy and the OSH intervention measures.  相似文献   
236.
Toona ciliata Roem. (Australian red cedar) requires a nurse-tree overstory to prevent damage from drought and irradiation in some regions of north-eastern Argentina. T. ciliata was planted in the understory of Pinus taeda L. (625 stems/ha), Pinus elliottii Engelm. × Pinus caribaea Morelet (625 stems/ha), and Grevillea robusta A. Cunn. (833 stems/ha) nurse trees, which were thinned to 0, 25, 50, 75 and 100% of the initial densities. We measured initial T. ciliata mortality and growth as well as Leaf Area Index (LAI) based on light transmission. T. ciliata soil water availability and its effect on early growth and mortality were examined by modelling drought stress using the two-dimensional forest hydrology model ForWaDy. Simulated patterns in T. ciliata water stress for the different overstory treatments were consistent with observed patterns of mortality. Early mortality was lowest with a G. robusta overstory, with corresponding lowest drought stress values and high modelled soil water contents in the top soil layer in intermediate and high overstory densities. Mortality was highest with a P. elliottii × P. caribaea overstory in treatments with the highest modelled drought stress values in the most open treatments. The model supported our field observations by indicating that water stress was an important limitation to T. ciliata survival and growth on our study sites. The linkage between T. ciliata establishment success, early growth and soil water availability as indicated by ForWaDy, leads us to conclude that the model is a suitable stand management tool for guiding establishment of T. ciliata plantations.  相似文献   
237.
基于归一化植被指数(NDVI)分析方法,利用黄山风景名胜区新云谷索道建设前(2004年)后(2008年)的2个时相的遥感数据对索道建设区进行植被覆盖动态变化分析。结果表明:新云谷索道建设后周边的植被覆盖和生长情况明显优于建设前,森林生态系统正向演替没有因为工程建设而受到限制,工程建设导致的人工干扰没有使植被遭受明显破坏,研究区植被生态系统的结构与功能没有因索道建设而受到影响。以遥感技术(Remote sensing,RS)为手段的风景区植被指数分析方法在生态环境研究中具有广阔的应用前景。  相似文献   
238.
以关中西部某铅锌冶炼区周边土壤为研究对象,采用潜在生态危害指数法对冶炼厂周边土壤的重金属污染特征和潜在生态风险进行了研究。结果表明:某铅锌冶炼区周边土壤中Pb、Zn、Cu、Cd、Cr、Hg、As、Ni的平均含量均高于陕西省土壤元素背景值。除Cr元素以外,其余7种重金属元素存在两两之间的极显著或显著的相关性。土壤中重金属污染物总的潜在生态风险指数为轻微生态风险。因此该铅锌冶炼区周边土壤存在不同程度复合污染组合类型,生态风险总体水平较低,但局部有中重度污染。  相似文献   
239.
结合小城镇环境生态区域广、生态类型多样且生态敏感度高等特点,采用DPSIR模式选取指标,建立了小城镇工业园区环境影响评价指标体系,在与城市工业园区比较、园区周围存在的农村生态系统方面提出增加资源能源利用、控制污染物排放的建议。  相似文献   
240.
城市生态文明建设评价指标体系构建   总被引:1,自引:1,他引:0  
城市作为人类环境问题和危机产生的重要策源地,建立反映城市生态环境问题和生态文明建设状态的评价指标体系,依据评价结论,指导城市生态文明建设十分必要。文章在城市作为社会—经济—自然复合人工生态系统的理论基础上,分析了社会生态亚系统、经济生态亚系统及自然生态亚系统相互作用关系和城市生态系统主要生物成分组成、结构与功能关系,系统的构建了符合中国国情的城市生态文明评价指标体系。该体系以生态经济、生态环境质量、生态社会为评价要素,下设12个一级指标及42个二级指标,为评价中国城市生态文明建设水平提供科学依据。  相似文献   
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