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321.
本文为我国的排污权交易设计了一套管理信息系统。该系统设计采用C/S和B/S混合架构体系,充分发挥了两者的长处。该系统一方面可以同时为环境管理部门、排污企业和社会公众三类主体提供信息化服务,大大方便了排污权的交易过程,并保证了排污权交易的公平与透明;另一方面可以使环境管理人员方便地查询和检索相关企业,简化了环境管理工作。  相似文献   
322.
本文以中秦岭地区为滑坡易发性评价对象,针对研究区的情况,选取了坡度、起伏度、地貌类型、岩性、土壤侵蚀强度、活动断裂距、地震动参数、地下水类型、多年平均降雨量9个评价因子,建立了研究区滑坡易发性评价的数据库。运用单因子概率比率模型对各因子和滑坡的相关性进行了评价,揭示了该区滑坡灾害类型特点及空间分布规律,明确了中秦岭地区滑坡地质灾害的极高易发、高易发三大聚集地区的位置。  相似文献   
323.
Density-dependent emigration has been recognized as a fitness enhancing strategy. Yet, especially in the modelling literature there is no consensus about how density-dependent emigration should quantitatively be incorporated into metapopulation models. In this paper we compare the performance of five different dispersal strategies (defined by the functional link between density and emigration probability). Four of these strategies are based on published functional relationships between local population density and emigration probability, one assumes density-independent dispersal. We use individual-based simulations of time-discrete metapopulation dynamics and conduct evolution experiments for a broad range of values for dispersal mortality and environmental stochasticity. For each set of these conditions we analyze the evolution of emigration rates in ‘monoculture experiments’ (with only one type of dispersal strategy used by all individuals in the metapopulation) as well as in selection experiments that allow a pair-wise comparison of the performance of each functional type. We find that a single-parameter ‘asymptotic threshold’ strategy - derived from the marginal value theorem - with a decelerating increase of emigration rate with increasing population density, out-competes any other strategy, i.e. density-independent emigration, a ‘linear threshold’ strategy and a flexible three-parameter strategy. Only when environmental conditions select for extremely high emigration probabilities (close to one), strategies may perform approximately equally. A simple threshold strategy derived for the case of continuous population growth performs even worse than the density-independent strategy. As the functional type of the dispersal function implemented in metapopulation models may severely affect predictions concerning the survival of populations, range expansion, or community changes we clearly recommend to carefully select adequate functions to model density-dependent dispersal.  相似文献   
324.
The effects of biologically active carbon (BAC) filtration on haloacetic acid (HAA) levels in plant effluents and distribution systems were investigated using the United States Environmental Protection Agency’s Information Collection Rule (ICR) database. The results showed that average HAA5 concentrations in all locations were 20.4 μg·L-1 and 29.6 μg·L-1 in ICR plants with granular activated carbon (GAC) and ICR plants without GAC process, respectively. For plants without GAC, the highest HAA levels were observed in the quarters of April to June and July to September. However, for plants with GAC, the highest HAA levels were observed in the quarters of April to June and January to March. This HAA level profile inversely correlated well with water temperature, or biologic activity. For GAC plants, simulated distribution samples matched well with distribution system equivalent samples for Cl3AA and THMs. For plants with and without GAC, simulated distribution samples overestimated readily biodegradable HAAs in distribution systems. The study indicated that through HAA biodegradation, GAC process plays an important role in lowering HAA levels in finished drinking water.  相似文献   
325.
326.
煤矿安全生产调度指挥信息系统及其应用   总被引:4,自引:0,他引:4  
介绍了煤矿安全生产指挥信息系统的由来、组成、特点、功能及其效果与前景。该系统以对煤矿安全生产指挥决策信息支持为目的 ,集矿山安全、工况监测及生产调度信息的采集、实时传输处理、图像 /图形显示、图形和数据存储管理及输出为一体 ,已在平煤集团公司多个矿区安装使用 ,产生了较好的经济效益及社会效益。  相似文献   
327.
This paper describes the environmental indicators GIS of the Catalan coast, Spain. The spatial data model is based on vector and raster layers with three main modules: the biodiversity, the general biophysical and the socioeconomic. Presently, the database has a number of pressure and impact indicators that have been used to model the components and structure of the system and are suggested to build ecological resilience. Special interest has been given to the analysis of functional groups of species that are relevant to the dynamics of the coastal system, and preliminary results are presented. This system constitutes a user-oriented analytical and monitoring tool for coastal zone managers and researchers. Although, the system is under development it is expected that resulting spatial indicators of environmental condition can be used to promote more sustainable coastal strategies and actions in the Catalan coast.  相似文献   
328.
Ascendency is an index of activity and organization in living systems calculated in terms of flows. The concern here is with how that quantity behaves when the flows in question are measured in terms of eco-exergy. The storage of eco-exergy has served as a goal function in assessing parameter values for structurally dynamic models, but network magnitudes and topologies can change in response to significant changes in the forcing functions. As storages are relatively insensitive to such changes, it is advisable in such cases to explore how changes in a flow variable, like ascendency, might capture network adaptations. It happens that changes in ascendency calculated in terms of flows of simple energy are small in comparison to corresponding variations in the storages of eco-exergy. But when ascendency is reckoned in terms of flows of eco-exergy, its changes in response to network changes are more comparable to those in the storages. Ascendency seems to be more sensitive to changes in flow topology, however, so that a combination of eco-exergy storage and eco-exergy ascendency would probably be most appropriate for situations where changes in flow topology are significant.  相似文献   
329.
生态系统服务内涵、价值评估与GIS表达   总被引:1,自引:0,他引:1  
生态系统服务价值评估是当前生态经济学领域的研究热点,为解决生态系统之于人类的重要性提供了量化的参考,也是生态补偿机制建立的重要依据.近5年国际上SCI论文发表数量以年均40%速度增长,我国研究起步于上世纪90年代末,十年来发展迅速,从对国外研究的简单模仿逐渐转向对评估模型参数的修正及对技术方法的适应性集成与发展.生态系统服务的内涵研究不断推进,在阐释“自然组分-生态过程-生态功能-生态服务.获得利益”关系上呈现多种观点,相应地提出了不同的价值评估指标体系;生态系统服务价值评估以瞬时静态为主,动态评估略显不足;研究对象从大尺度和单一生态系统逐渐转向中尺度区域,评估结果表现形式从单一数值化向基于GIS的空间表达发展.在回顾全球范围生态系统服务评估研究成果的基础上,从研究区域分布与学科特点、内涵及分类、评估方法和GIS技术应用等四大方面进行归纳分析,并从生态系统管理和决策支持需求的角度,指出生态系统评估研究已取得显著进展,但有关生态系统服务的内涵与分类、生态系统服务价值的动态评估及GIS技术的应用研究仍待深入.  相似文献   
330.
社区大气污染物排放总量控制研究   总被引:9,自引:0,他引:9  
李达  蒋家文  陈波洋  钱枫 《环境科学》1999,20(5):97-101
为了寻求社区大气污染物排放总量控制的方法和可行途径,在污染源调查的基础上,以城市多源大气扩散模式(ISCST)为建模工具,采用以“总量控制线性方程组”作为约束条件的线性规划方法,对控制北京市西城区大气污染物排放总量达到环境目标的几种方案作了分析,如燃烧优质煤和天然气等。同时,给出了总量控制管理信息系统的结构图和功能图。  相似文献   
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