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141.
中国二氧化硫污染的“稳健性”影响因素——基于空间面板数据EBA模型的实证分析 总被引:3,自引:1,他引:2
改革开放以来,中国的经济发展取得了举世瞩目的成就.然而,随着经济的快速增长,环境污染问题也日益凸显.本文采用2000—2012年中国30个省际的面板数据,利用环境库兹涅茨曲线(EKC)理论检验二氧化硫(SO2)污染与经济增长的关系及其空间溢出效应,进而引入极值边界模型(EBA模型)实证检验SO2污染的"稳健性"影响因素.结果表明:我国各省域SO2污染与经济增长存在EKC曲线假设的倒"U"型关系,并具有空间溢出效应;第二产业就业人口比重、出口占GDP的比重、能源效率、化石能源比重、工业污染治理完成投资与SO2排放量呈正向"稳健性"关系,产业结构升级与SO2排放量呈负向"稳健性"关系.最后根据实证结论提出相应的政策建议,为政府制定相应的SO2减排政策提供经验证据和决策参考. 相似文献
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国内已从宏观尺度研究全国A级旅游景区的空间分布情况,但有关区域性旅游景区空间分布的研究较少。山东半岛蓝色经济区作为中国第一个蓝色经济战略区,具有很强的代表性。选取山东半岛蓝色经济区的284处A级旅游景区作为研究样本,利用蓝色经济区不同等级景区在各市区分布折线图得到不同等级景区的空间分布差异。利用空间分析和数理统计的方法,包括地理集中指数和基尼系数对其进行分析,辅以洛伦茨曲线对结论进一步验证,最终得到蓝色经济区的A级旅游景区在空间上呈现出集群分布、不均匀分布特点。采用聚类分析确定了旅游节点和旅游轴线,确立了以青岛为核心,向周围城市辐射发展的空间格局。 相似文献
143.
Water temperature not only affects the solubility of gas in water but can also be an important factor in the dissipation process of supersaturated total dissolved gas (TDG). The quantitative relationship between the dissipation process and temperature has not been previously described. This relationship affects the accurate evaluation of the dissipation process and the subsequent biological effects. This article experimentally investigates the impact of temperature on supersaturated TDG dissipation in static and turbulent conditions. The results show that the supersaturated TDG dissipation coefficient increases with the temperature and turbulence intensity. The quantitative relationship was verified by straight flume experiments. This study enhances our understanding of the dissipation of supersaturated TDG. Furthermore, it provides a scientific foundation for the accurate prediction of the dissipation process of supersaturated TDG in the downstream area and the negative imp)acts of high dam projects on aquatic ecosystems. 相似文献
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Effects of metsulfuron-methyl on the microbial population and enzyme activities in wheat rhizosphere soil 总被引:1,自引:0,他引:1
He YH Shen DS Fang CR He R Zhu YM 《Journal of environmental science and health. Part. B》2006,41(3):269-284
The effects of metsulfuron-methyl, a sulfonylurea herbicide, on the wheat soil microorganisms were evaluated by the methods of microbial inoculation culture, and the activities of three enzymes were measured using the colorimetric method. The tolerant microorganisms that can resist 500 microg x g(-1) metsulfuron-methyl in the counting culture medium were studied specially. Metsulfuron-methyl distinctly inhibited the common aerobic heterotriphic bacteria, but the effects on common fungi and common actinomycete were not evident. In the meantime, the number of tolerant fungi increased greatly in the rhizosphere after the application of metsulfuron-methyl in contrast to the significant decrease of the amount of tolerant actinomycete. It indicates that fungi might turn into the dominant microbial type and actinomycete is the sensitive factor in the soil polluted by sulfonylurea residues. The population of aromatic compounds-decomposing bacteria, aerobic azotobacter, and nitrite bacteria all increased in the earlier period, but the aerobic azotobacter decreased rapidly in number 30 days later, and the amount of nitrite bacteria also showed a temporary decrease with time 15 days later. However, the denitrifying bacteria just began to increase significantly after the crops had grown for 50 days. The amount of sulfur-oxidizing bacteria gradually decreased with the growth of crops, and so were the sulfate-reducing bacteria after metsulfuron-methyl application. To all types of microorganisms, there were more microbes in rhizosphere samples than those in nonrhizosphere except aerobic azotobacter. It means the growth of wheat root system can stimulate the growth of most microorganisms. The activities of hydrogen peroxidase and polyphenol oxidase in soil samples after metsulfuron-methyl application were notably lower than those in the control, and the difference of the activities between the samples of rhizosphere and nonrhizosphere was evident. On the contrary, the activity of dehydrogenase was not inhibited by the application of metsulfuron-methyl, and the rhizosphere effect was not obvious either. 相似文献
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淡水是人类赖以生存的资源,淡水的短缺已成为制约经济发展的重要因素之一,并危及人类的生存。解决淡水危机,加强淡水资源利用和管理已刻不容缓。对城市进行分流供水,对产生的废水进行分流回收处理,是实现淡水资源的持续利用,满足城市用水需要的新思路 相似文献
150.
水环境中重金属污染研究概述 总被引:32,自引:2,他引:32
重金属污染是水环境污染的一个重要方面,而水质模型是重金属污染研究的重点方法之一,作者在对溪落渡水库重金属污染的研究工作过程中,收集和整理了大量有关资料,本文概述了目前常用的重金属迁移转化动力学数学模型及建立该模型时所涉及到的重金属存在形态、污染特征,迁移转化过程等方面的研究成果和存在问题。 相似文献