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71.
As uranium has practically no other industrial uses besides electricity generation, demand is determined by the requirements and stockpiling policies of electric utilities. The uranium market has experienced strong fluctuations and is currently affected by the reductions in nuclear forecasts resulting from the slowdown in electricity demand. Analysing supply/demand indicators proves, however, that in retrospect the development has been relatively smooth and it appears that oversupply is more a consequence of overly optimistic short-term expectations. In the future, especially in the long term, nuclear power policies continue to be concerned with striking a proper balance between increasing production capability and development of new reactor technologies which would be less dependent on the availability of uranium. A bounding scenario approach is applied in this article to the assessment of adequacy of supply under varying assumptions on the total installed nuclear capacity, available resource base and attainable production capability. 相似文献
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73.
中和-络合萃取-双极膜电渗析处理金刚烷胺制药废水 总被引:1,自引:0,他引:1
采用中和沉淀-络合萃取-双极膜电渗析组合工艺协同处理金刚烷胺制药胺化废水与溴化废水.结果表明,通过胺化废水与溴化废水的中和反应,可以大幅消减废水中溶解性固体和有机污染物,避免后续萃取过程中的乳化现象.在pH值为8.0、油/水相比为1∶1的条件下,P204∶正辛醇=3∶2的复配萃取剂对废水中TOC和TN的萃取效率分别为56.9%和20.6%,金刚烷胺及其衍生物几乎被完全萃取.以2.0 mol·L-1的HCl溶液为反萃取剂,可以将47.5%的金刚烷胺从负载有机相中反萃分离,再生后的萃取剂可以多次重复使用.对萃余液采用双极膜电渗析进行处理,可以去除64.2%的无机盐和部分有机物,同时还能回收到较高浓度的酸,但由于氢离子的渗漏难以回收高浓度的碱. 相似文献
74.
铜及其与四环素的联合暴露对斑马鱼胚胎的毒性效应 总被引:1,自引:0,他引:1
近年来工业和养殖业中铜和四环素的滥用,导致了一定程度的水环境污染问题。为探究铜与四环素对水生生物的毒害作用,选择斑马鱼作为受试生物,研究了铜及其与四环素的联合暴露对斑马鱼胚胎的毒性效应,并进一步探索了其中可能的致毒机制。结果表明:铜在低浓度下(10%致死浓度LC10=2.5μg·L~(-1),10%效应浓度EC_(10)=0.1μg·L~(-1))明显延迟了斑马鱼胚胎的孵化、卵黄囊吸收、头部、鱼鳔和体长等生长指标的发育,同时在心脏区域引起了明显的细胞凋亡效应。幼鱼体内总铜含量检测结果显示低浓度下铜的生物利用度相对更高。基因表达结果显示环境浓度的铜可能通过影响神经和心脏相关基因的表达引起斑马鱼胚胎的神经发育和心脏发育异常。铜和四环素的联合暴露实验结果表明二者的复合污染类型为拮抗作用,且两者相互作用可以形成络合物。综合以上结论,说明环境浓度的铜可能通过细胞凋亡、分子水平的变化等方式对水生生物的早期生长发育产生危害,如延迟生长发育、神经及心脏发育异常,另外铜可通过和四环素等环境中其他污染物的结合改变铜的生物有效性和毒性。 相似文献
75.
76.
复合污染条件下人为源VOCs的SOA生成研究进展 总被引:1,自引:1,他引:0
大气细颗粒物(PM2.5)仍是我国空气质量持续改善的重大挑战.近年来,二次有机气溶胶(SOA)对PM2.5的贡献日益凸显.因此,深入认识复合污染条件下SOA生成机制和影响因素可以为进一步降低PM2.5提供重要理论依据.实验室模拟是深入认识SOA生成机制的关键途径,也是模式模拟参数化方案的可靠来源之一.主要综述了我国多污染物共存条件下典型人为源挥发性有机物(VOCs)的SOA生成研究进展,包括汽油蒸气VOCs、生物质燃烧VOCs和含氧VOCs形成SOA过程中,前体物浓度、芳香烃含量、无机气体、种子气溶胶和相对湿度(RH)等不同因素对SOA生成的影响;阐述了实际大气VOCs的SOA生成潜势及其影响因素,最后提出了目前在SOA机制研究方面存在的关键科学问题,并对未来的研究方向进行了展望. 相似文献
77.
78.
通过对区域安全发展和人才支撑方面的研究综述,从系统理论出发构建了区域安全发展与人才支撑复合系统,并对复合系统理论作出假设和理论分析,进一步研究了复合系统的协调性。在此基础上,对山西安全发展与人才支撑复合系统的协调性进行了实证研究,从人才支撑角度提出了实现山西安全发展的对策与措施。 相似文献
79.
A. Gauthier P. Le Coustumer M. Motelica O. F. X. Donard 《Waste management (New York, N.Y.)》2000,20(8)
The development of predictive models for the long term evolution of nuclear waste glass requires the complete knowledge of the glass dissolution at the laboratory scale. A new approach was developed to determine the initial reaction during the first steps of experience, a new concept was developed, based on the combination of dynamic leaching test and the characterization of the altered materials. With this experimental set-up it is possible to follow in real time the glass alteration process at a fine temporal scale. The results put in evidence a singular behaviour of the lanthanide, shown by a concentration peak of La, Nd and Ce after 2 h and a quick decrease of their concentration measured on line in the solution during the leaching test. This fact is directly linked to the development of an interphase (altered layer which differs from the initial solid by its texture, structure and chemical composition) at the interface of the glass surface and the leaching solution. This work is an attempt to integrate the formation of the alteration products (here the interphase) during leaching into the dissolution mechanisms of a nuclear waste glass. A model is proposed and discussed. 相似文献
80.
A total of six nuclear reactors installed in three power plants, two along the northern and one along the southern coasts of Taiwan, started their operations one after another since October 1977. Owing to the large quantities of cooling water intake into and discharge from the plants, some environmental factors such as water temperature, chlorine, environmental radioactivity and nearshore currents may be significantly changed. Variations of these abiotic environmental factors may influence the biological activities in the ecosystem, particularly doing some kinds of damage to marine biological resources. Therefore, the possible environmental impact upon the biological systems including the fishery resources along the northern and southern coasts of Taiwan should be studied before and during the plant operation.
We have started the long-term programmes of biological, chemical and hydro-graphical surveys of the nuclear power plant sites on both northern (since July 1974) and southern (since July 1979) coasts of Taiwan. the survey items include ocean currents, physical and chemical properties of sea water, primary productivity, specific compositions and interspecific relationships among phyto- and zooplankton, algae, invertebrates, corals, and fishes; and radionuclides in water and biological specimens, and fishery statistics. in general, except for a few events, the operations of the six units of nuclear power plants have not produced detectable effects on the marine ecosystem. Radio activity levels and radionuclides in water and the biological specimens remained the same as background levels throughout the survey period. However, the events of coral bleaching and fish body anomalies caused by thermal discharges were observed respectively along the outlets of third and second Nuclear Power Plants. the purposes of this paper are to report and evaluate these two events during the operations of nuclear power plants in Taiwan. 相似文献
We have started the long-term programmes of biological, chemical and hydro-graphical surveys of the nuclear power plant sites on both northern (since July 1974) and southern (since July 1979) coasts of Taiwan. the survey items include ocean currents, physical and chemical properties of sea water, primary productivity, specific compositions and interspecific relationships among phyto- and zooplankton, algae, invertebrates, corals, and fishes; and radionuclides in water and biological specimens, and fishery statistics. in general, except for a few events, the operations of the six units of nuclear power plants have not produced detectable effects on the marine ecosystem. Radio activity levels and radionuclides in water and the biological specimens remained the same as background levels throughout the survey period. However, the events of coral bleaching and fish body anomalies caused by thermal discharges were observed respectively along the outlets of third and second Nuclear Power Plants. the purposes of this paper are to report and evaluate these two events during the operations of nuclear power plants in Taiwan. 相似文献