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981.
在建高楼火灾灭火困难。在建高楼灭火以及人员疏散的关键在于对灾变条件下在建高楼火灾参数变化的正确预测,特别是火焰、烟气蔓延范围、烟气浓度变化以及有毒气体的扩散范围等参数的预测。为了获得在建高层建筑物的火灾参数,论文利用美国国家标准和技术研究院(NIST)开发FDS(Fire Dynamics Simulator)软件,建立在建高楼模型,对高楼火灾进行全尺寸模拟,通过对模拟实验数据处理和分析,给出了在建高楼发生火灾时烟气浓度和氧气浓度纵向温度的变化规律以及不同方向风速对火灾的影响,提出一种阻火方案,并验证了它的阻火效果,为防灾减灾和消防决策提供有力的依据。  相似文献   
982.
输电线路除冰技术的研究   总被引:3,自引:0,他引:3  
目前,如何对覆冰输电线路进行融冰、除冰以降低冰灾损失仍是世界性的技术难题,通常的融冰措施可分为热融冰、机械除冰及自然脱冰。该文分别简要阐述了这三类措施,并对每一类方法中具有代表性的或较新颖的融冰方法进行了介绍,同时分析了各方案的利弊及应用范围,并介绍了国际上在此领域的一些新的研究成果。  相似文献   
983.
《新闻联播》对年初的南方冰雪灾害和汶川地震进行了大量的报道,我们通过对这些报道资料的收集和整理,在进行定量分析和定性分析的基础上认为:《新闻联播》对于南方冰雪灾害和汶川地震的报道存在一定的变化,这些变化体现了《新闻联播》在灾害事件报道的探索中不断发展。本文指出了取得进展的各个方面,并分析了取得这些进展的原因。  相似文献   
984.
985.
Persistent organochlorine pesticides pollutants (OCPs) have been reported to occur at relatively high concentrations in some Chinese waters. In order to map the distribution of organochlorine pesticides in the surface water throughout China, samples were collected from over 600 sites in seven major river basins and three main internal rivers drainage areas during 2003 and 2004. The surface water samples were analyzed for the representative organochlorine pesticides contaminants including lindane (gamma-HCH), p,p'-DDT and heptachlor epoxide. In general, the most frequently detected compound was lindane, being detected in 83.9% of samples (mean=31.3 ng/l; range <0.17-860 ng/l), and the highest concentration was present in the Yellow River basin. p,p'-DDT was detected in 63.1% of the samples collected (mean=14.6 ng/l; range <0.14-368 ng/l) with the highest concentration present in the Huaihe River basin. Heptachlor epoxide was detected in only 9.3% of water samples (range <0.11-10 ng/l). Measured concentrations for the three compounds were low and rarely exceed the environment quality standard for surface water of China. Lindane was more frequently detected at much higher concentrations in the rivers of northern China compared with those of southern China. The sites with higher concentration of lindane and p,p'-DDT mainly occurred in the Yellow River and Huaihe River basins, so the results of this investigation indicate that the organochlorine pesticide contamination of Yellow River and Huaihe River basins should be of particular concern relative to the other basins. When compared with other regions of the world, it appears that the Chinese surface water is moderately polluted by lindane and p,p'-DDT.  相似文献   
986.
Thirteen areas around the Chinese Bohai coast, individuals including ten kinds of bivalves and two kinds of snails were collected during the period of 2002-2005 for the investigation of spatial distribution and temporal variations of butyltin compounds (BTs). BTs including tributyltin (TBT) and its derivates, dibutyltin (DBT) and monobutyltin (MBT) were quantified by gas chromatography/flame photometric detection after extraction and Grignard derivatization. BTs compounds were widely existed in the samples and TBT was the dominant composition, indicating recent TBT input along Bohai coast. As a whole, BTs concentration remained high during the sampling years except a slightly decreased in samples from several sites in 2005. The contamination characteristics of BTs in different sampling sites were analyzed using principal component analysis (PCA) method, and the species specific bioaccumulation of BTs was also identified using cluster analysis.  相似文献   
987.
Rural human settlement is a significant indicator of the living standards of rural residents, and its improvement can contribute to promoting the positive interaction between inhabited environment and the social, economic, and resource environment in the countryside. Based on 557 valid questionnaires of satisfaction evaluation of human settlement in the peripheral metropolitan area of Beijing, this paper analyzed the elemental characteristics and factors influencing human settlement quality using multivariate statistical analysis and a structural equation model. The result shows that, first, the rural residents in a peripheral metropolitan area of Beijing are generally satisfied with the quality of human settlement (satisfaction rate is 66.2%). Specifically, the natural and social environment of the countryside is excellent and harmonious and corresponding standard of countryside infrastructure is advanced, but the quality of public services and follow-up management of facilities are in urgent need of improvement and the imbalance between revenue and expenditure of rural households has led to a continuous increase in the pressures of life. Second, factors such as social atmosphere, appearance of the village, entertainment, living costs, fundamental public services, and production costs have significant effects on human settlement quality in this peripheral metropolitan area, with social atmosphere as the main one. Living costs and supporting services are the main constraints to improvement in the quality of human settlement.  相似文献   
988.
在快速城市化过程中,城市不断扩张而产生的蔓延现象与土地可持续发展紧密相关,合理控制城市蔓延度可以节约资源,促进城市内涵式发展。根据蔓延度内部机理和分形理论构建蔓延测度指标体系,采用GIS方法,通过分维数、空间稳定性等指数,以马鞍山市为例分析研究区城市蔓延度特征和时空差异。研究表明:(1)分形理论适用于城市蔓延度的定量研究;(2)从时间维度看,研究区内部不同区域间的蔓延趋势总体相似,但蔓延程度有所差异;(3)从空间维度看,蔓延度与分维数、建设用地破碎度呈正相关,与空间稳定性指数呈负相关。马鞍山市城市蔓延的机制是土地导向,经济发展是抑制过度蔓延的动力。  相似文献   
989.
作为洞庭湖一级支流,澧水对洞庭湖乃至长江水系鱼类资源的维持或补充有着重要作用。为了了解澧水的鱼类资源现状,于2010年4月~2011年12月,对湖南境内澧水水系鱼类资源进行调查。共采集鉴定鱼类95种(包括1种湖南鱼类新纪录,4种外来种),隶属于8目19科59属。种类组成以鲤科鱼类为主,占5053%。多样性分析表明,澧水不同江段鱼类群落多样性处于较好或丰富状态,在空间分布上,鱼类物种数按上、中、下游依次增加,多样性指数也呈上升趋势且差异显著(P<005)。相似性及聚类分析表明,澧水鱼类群落可分为3个类群,即:上、中、下游类群;上游与中游类群为中等相似,与下游类群为中等不相似,中游与下游类群相似性总体小于与上游类群相似性。澧水鱼类在洄游、摄食、栖息习性等生态类型上呈现多样化特征。调查江段渔获物组成虽存在差异,但主要以鲤、鲫、翘嘴鲌、蒙古鲌、鲇、黄颡鱼、[XCz1.tif;%85%85,JZ]、银鮈、中华花鳅、子陵吻鰕虎鱼等湖泊定居性或山溪流水性[JP3]鱼类为主,“四大家鱼”等洄游性鱼类所占比例极低,鱼类小型化现象明显,原因分析主要与水工建设和过度捕捞有关。[  相似文献   
990.
Abstract

In order to study the relationship between economic globalization and industrial pollution, this paper developed the theoretical framework and used simultaneous equations. The result shows that economic globalization has influences on the industrial pollution mainly by the direct effect of scale, structure and technology as well as the indirect effect of income and policy. Considering all the factors, economic globalization, especially foreign direct investment (FDI), will reduce industrial pollution, in which technology spillover effect plays an important role.  相似文献   
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