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991.
我国是一个地震多发的国家,地震灾害给我国造成了巨大的经济损失和严重的生命伤亡。专业化的震后紧急搜索救援能够最大限度地减少人民生命财产的损失,是防震减灾体系不可或缺的组成部分。通过大量的地震灾害实例,并借鉴地震灾害评估方法和建筑物抗震设计,对危害人类生命财产的建筑物震害的特征按照结构类型进行了详细说明,通过对这些地震中常见震害的了解和认识,为国家地震紧急救援训练基地的规划设计和相应搜索救援训练科目的设置提供依据。  相似文献   
992.
ABSTRACT: In‐reservoir thermal and ecological effects of releasing some flows over the surface spillway at Blue Mesa Reservoir, Colorado, rather than routing all releases through the hypolimnetic outlet were evaluated using a calibrated and validated one‐dimensional thermal model (CE‐THERM) with a set of ecological models. Thermal model output indicated that surface water temperatures were influenced primarily by atmospheric conditions, but the release of warmer water over the spillway resulted in a thinner epilimnion and cooler metalimnetic water temperatures. Ecological model predictions indicated that spillway releases and associated temperatures resulted in lower growth rates for young‐of‐year (YOY) kokanee salmon (Oncorhynchus nerka) in the reservoir by up to 9 percent when compared with growth rates under baseline operations with no releases over the spillway. Kokanee growth rates were reduced under spillway release scenarios because lower temperatures not only affected metabolic rates, but limited the productivity of the zooplankton as well. Thus, altering the release regime with spillway discharges could have deleterious effects on Blue Mesa's YOY kokanee. However, in other reservoirs, distributing discharges among different elevations may provide managers with a mechanism to regulate temperatures to benefit species of concern that are facing challenges imposed by environmental conditions such as global warming.  相似文献   
993.
The results of phenetic studies on chum salmon populations from the rivers flowing into Taui and Yama bays, Sea of Okhotsk, are discussed. The heterogeneity of samples with respect to the frequency of a certain phene in females is not necessarily revealed when this frequency is analyzed in males. Statistically significant heterogeneity with respect to phene frequencies is observed in all chum salmon populations, whether the corresponding data are analyzed by years or throughout the observation period. This population heterogeneity is accounted for by specific phenetic features of each chum salmon population, although in different years it manifests itself in the frequencies of different phenes. The phenes distinguished on the head of fish contribute most significantly to interpopulation differences.  相似文献   
994.
ABSTRACT: A model was developed of the periodic-stochastic structure of daily precipitation over an area. The model is based ona multivariate normal distribution. The square roots of daily precipitation at a point were found to approximate a sample from a univariate normal distribution that had been truncated at zero. The zero daily precipitation amounts were considered negative amounts of unknown quantity. The multivariate normal distribution was used to describe the variation of daily precipitation over an area. The periodic fluctuations of the model parameters were described with Fourier series. The model was tested using data from two areas of different precipitation characteristics. Data generated with the model contained many of the statistical characteristics observed in the historical data.  相似文献   
995.
火灾环境下具有弹性支座钢构件的稳定性能   总被引:5,自引:0,他引:5  
根据弹性稳定理论原理研究了具有弹性支座钢结构构件在火灾环境下的静力特性问题 ,导出了高温下钢构件的静力稳定临界荷载和长度计算式 ,并讨论了温度、杆件的侧向弹簧刚度、杆长、保护层厚度等因素对杆件静力稳定临界荷载和长度的影响 ,分析表明 ,杆件的侧向弹簧刚度、杆长、保护层厚度对杆件的稳定承载力影响较大 ,并探讨了在实际工程中如何减小结构失稳的问题。  相似文献   
996.
Radioactive contamination of agricultural land may necessitate long-term changes in food production systems, through application of selected countermeasures, in order to reduce the accumulation of radionuclides in food. We quantified the impact of selected countermeasures on habitat diversity, using the hypothetical case of two agricultural areas in Finland. The management scenarios studied were conversions from grassland to cereal production and from grassland and crop production to afforestation. The two study sites differed with respect to present agricultural production: one being predominantly cereal production and seminatural grasslands, while the other was dominated by intensive grass and dairy production. Some of the management scenarios are expected to affect landscape structures and habitat diversity. These potential changes were assessed using a spatial pattern analysis program in connection with geographic information systems. The studied landscape changes resulted in a more monotonous landscape structure compared to the present management, by increasing the mean habitat patch size, reducing the total habitat edge length and reducing the overall habitat diversity calculated by the Shannon diversity index. The degree of change was dependent on the present agricultural management practice in the case study sites. Where dairy production was predominant, the landscape structure changes were mostly due to conversion of intensive pastures and grasslands to cereal production. In the area dominated by cereal production and seminatural grasslands, the greatest predicted impacts resulted from afforestation of meadows and pastures. The studied management changes are predicted to reduce biodiversity at the species level as well as diminishing species-rich habitats. This study has predicted prominent side effects in habitat diversity resulting from application of management scenarios. These potential long-term impacts should be considered by decision-makers when planning future strategies in the event of radionuclide deposition.  相似文献   
997.
本文针对当前环保产业调整中存在的问题,提出了需要解决的五个方面和应处理好的几个关系。  相似文献   
998.
推进环保产业结构调整的思考   总被引:2,自引:0,他引:2  
文章对环保产业结构调整要解决的问题进行了分析,指出产业结构调整必须符合市场经济要求的布局和流通结构,只有建立现代化的企业制度,企业才能有活力。  相似文献   
999.
区域资源开发的系统转换理论   总被引:2,自引:0,他引:2  
作者在分析资源与资源功能的基础上,以区际资源功能互补转换和区内资源结构对应转换为主题,论述了有关“区域资源开发的系统转换理论”的新思想。  相似文献   
1000.
The character of the current controversy over geneticallymodified (GM) agriculture, typified by protesters' use of emotivesymbolism, has been largely inspired by the Green movement'snon-governmental organizations and political parties. This articleexplores the deeper philosophical and spiritual motivations of the Greenmovement, to inquire why it is implacably opposed to GM agriculture. TheGreen movement's anti-capitalism, exemplified by the hate-symbol statusof Monsanto as the company pioneering GM crops, is viewed within thewider context of alienation in the modern era. A complex of meanings isseen in Frankenstein as the focal symbol of GM protests, includingperceptions of risk, fears of the remixing of living identities seen ingenetic engineering, and resentment at the spiritual nihilism of thereduction of life to the digital code of DNA. By contrast, RobertGoodin's Green Theory of Value, which postulates the deep psychologicalimportance of nature in locating the self in a meaningful context largerthan ourselves, can explain the power of the Green symbol of thethreatened environment, Gaia. The advent of GM agriculture seems toimply that capitalism and technology can now enframe nature itself,leaving a world devoid of natural myth or meaning, with no escape fromthe alienation and nihilism of modernity. The central question posed forprotagonists of the GM debate is whether their agenda is based on thesepowerful but mythical conceptions of the environment, or whetherpreservation of the real environment is their primary ethic.  相似文献   
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