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201.
基于物元模型的煤自燃危险性分析   总被引:4,自引:2,他引:2  
为探索判断煤自燃的危险性新方法,在煤低温氧化试验的基础上,基于可拓理论构建了煤自燃危险性熵权和经验权的物元综合分析模型。采用该方法对4个不同煤样低温氧化试验数据进行自燃危险性分析,得出各煤样自燃危险性的等级及差异程度,并提出相应的防范对策。结果表明:4号煤样比其他煤样更具自燃危险性,需要重点防范。该方法的预测结果与实际情况相吻合。  相似文献   
202.
Elizabeth Anderson’s “pluralist–expressivist” value theory, an alternative to the understanding of value and rationality underlying the “rational actor” model of human behavior, provides rich resources for addressing questions of environmental and animal ethics. It is particularly well-suited to help us think about the ethics of commodification, as I demonstrate in this critique of the pet trade. I argue that Anderson’s approach identifies the proper grounds for criticizing the commodification of animals, and directs our attention to the importance of maintaining social practices and institutions that respect the social meanings of animals. Her theory alone, however, does not adequately address the role of the state in this project. Drawing on social contract theory to fill this gap, I conclude that the state’s role in regulating the pet trade should be limited to ensuring the welfare of animals in the stream of commerce, not prohibiting their mass marketing altogether.  相似文献   
203.
ABSTRACT: The concept of recurrence interval has been used for years in engineering designs. Can the same concept be applied to the drought analysis? This paper uses the plotting position method to define drought of various recurrence intervals based on stream-flow data. The method of truncation level was applied to the same data to examine the defined drought. Based on the method of truncation level, drought duration and its corresponding flow deficit were investigated. Eighteen flow gage stations from the Scioto River Basin in Ohio were selected for the study. The results show that flows of 100-year droughts using the plotting position method are practically nil. On the other hand, flows of droughts using the truncation method are gradually decreasing with an increase in truncation level, where flows of 95 percent are approximately equal to those of two-year droughts defined by the plotting position. It is also shown that there is a strung correlation between drought duration and deficit.  相似文献   
204.
冯玉国 《四川环境》1994,13(2):36-38
本文根据灰色关联分析的基本性质,提出一种环境质量综合评价的新方法。该方法用待评价样本各指标值组成参考数列,环境质量分级标准值组成被比较数列,通过计算参考数列与被比较数列的关联度,按最优关联识别原则综合评价环境质量等级。用4个实例与其它方法进行了对比,取得满意的效果。  相似文献   
205.
应用分形理论,研究了煤矿顶板运动过程中所表现的分形特征,提出了用顶板下沉速度的分数维值的变化预报顶板来压、冒落的方法,使得预报顶板来压、冒落的指标定量化成为可能,预报更加科学,把预报的理论与方法推进到新阶段。这对保障煤矿生产安全具有重要的应用价值。  相似文献   
206.
The Columbia River Basin is the scene of a massive effort to restore populations of Pacific salmon (Oncorhynchus spp.) and steelhead (O. mykiss). Efficient restoration is confounded by a high level of complexity, competing sociopolitical goals and values, and uncertainty about key system properties. Simulation models and other tools of systems analysis are important to development of a comprehensive, regionally acceptable strategy. Hierarchy theory provides a useful paradigm for organized complexity within the Columbia Basin and the basis for a trilevel hierarchical structure for organizing and integrating models. Life-stage models compose the most basic simulation units at the lowest level in the proposed hierarchical modeling structure. Each life-stage model simulates a distinct period in the life cycle of anadromous salmonids. Population models at the intermediate level simulate the complete life cycles of salmon and steelhead populations. At the highest level in the hierarchy, interpopulation models simulate extensive, long-term processes that affect multiple species and stocks. A hierarchical system of models is preferable to a single model or to a group of models lacking formal structure. A principal advantage is that models have the correct spatial and temporal resolution for analyzing questions at different scales. A hierarchical structure also facilitates the flow of information among models, and aids in understanding the impacts of uncertainty. Constructing a hierarchy of models should involve both bottom-up and top-down perspectives that maintain logical consistency among models, while allowing unique model structures appropriate for each level in the hierarchy.  相似文献   
207.
刘乾云 《灾害学》1995,10(1):93-96
地球系统是宇宙系统的全息缩影,地球上的灾害和天体之间具有全息关系,同样有恒定的周期性。本文根据全息理论对灾害进行分析预测,并建议在灾害研究中应用全息理论.  相似文献   
208.
分形块体理论及其在三峡高边坡稳定分析中的应用   总被引:4,自引:0,他引:4  
把分形几何与块体理论相结合,提出了分形块体理论,建立了分形块体理论赤平解析法,并将其应用于三峡永久船闸高边坡稳定性分析中。结果表明:分形块体理论符合工程实际,是分析裂隙岩体工程稳定性行之有效的可靠方法。  相似文献   
209.
This paper focuses on the development plan activities of the London Boroughs and simply seeks to explain the relatively limited progress that has been made in the preparation and adoption of statutory local plans, by showing how production was constrained as local planners were caught up in the shifting ground of contemporary planning theory. The author suggests that uncertainty about the acceptable scope and content of local plans, at a time when planners were being encouraged to extend the emphasis of their work beyond the purely physical, led to serious problems as planners began to experiment with new approaches to local planning but failed to appreciate the operational implications of each approach.  相似文献   
210.
This paper presents an integrated system for the assessmentof technical and non-technical measures that are putforward in order to reduce air pollution levels in urbanareas. In contrast to the majority of the currentlyemployed assessment tools, this system allows for theevaluation of any proposed air pollution control measure interms of its combined impact on air quality and socialwelfare, by correlating the environmental and economicaspects of alternative air pollution abatement solutions.Based on the multi-pollutant, multi-effect concept, thesystem presented aims in providing policy-makers with areliable tool for the objective assessment of the mostcost-effective packages of measures, the latter beingallocated according to the particular features and needs ofthe areas examined.  相似文献   
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