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91.
Atmospheric air samples were taken within 3 km from power plants encompassing five different distances and wind directions. Samples were taken between 2002 and 2005 aiming to evaluate the environmental 14C enrichment due to the operation of Brazilian nuclear power plants. The sampling system consisted of a pump connected to a trapping column filled with a 3 M NaOH solution. The trapped CO2 was analyzed for 14C by using a single stage accelerator mass spectrometry (SSAMS).  相似文献   
92.
肖婷玉  束韫  李慧  王涵  李俊宏  严沁  张文杰  姜华 《环境科学》2024,45(3):1265-1273
为量化评估太原市“十四五”大气污染防治政策的减污降碳协同效益,使用京津冀温室气体-空气污染相互作用与协同模型(GAINS-JJJ),模拟评估13项大气污染防治措施的减排潜力,CO2的协同减排效益.2025年政策情景下一次PM2.5、PM10、SO2、NOx、VOCs和NH3分别减排1.8(5%,相对于基准情景减排比例,下同)、2.5(2%)、3.7(16%)、20.0(27%)、13.6(15%)和0.0 kt(0%),CO2减排9.0 Mt(13%),CH4排放增加203.3 kt(相对于基准情景增加25%).SO2、NOx与VOCs减排主要发生在电力、工业燃烧与溶剂使用部门,CO2减排主要发生在工业燃烧部门,CH4排放量增加是由于煤矿开采活动水平升高.限制“双高”行业的能源消耗,严禁新增产能以及可再生能源发电比例提升措施的CO2协同减排效益最高.VOCs具有优异协同减碳效益.建议太原市进一步推进终端电气化政策,同时需加大提升电力行业清洁能源比重和可再生能源发电的消纳能力.  相似文献   
93.
A dynamic compartment model was investigated to describe 14C accumulation in rice plants exposed to atmospheric 14C with temporally changing concentrations. In the model, rice plants were regarded to consist of three compartments: the ear and the mobile and immobile carbon pools of the shoot. Photosynthetically fixed carbon moves into the ear and the mobile carbon pool, and these two compartments release a part of this carbon into the atmosphere by respiration. Carbon accumulated in the mobile carbon pool is redistributed to the ear, while carbon transferred into the immobile carbon pool from the mobile one is accumulated there until harvest. The model was examined by cultivation experiments using the stable isotope, 13C, in which the ratios of carbon photosynthetically fixed at nine times during plant growth to the total carbon at the time of harvest were determined. The model estimates of the ratios were in relatively good agreement with the experimental observations, which implies that the newly developed compartment model is applicable to estimate properly the radiation dose to the neighboring population due to an accidental release of 14C from nuclear facilities.  相似文献   
94.
As part of the Danish NEAREX project the origin and variability of anthropogenic atmospheric CO2 over the Northeast Atlantic Region (NEAR) has been studied. The project consisted of a combination of experimental and modelling activities. Local volunteers operated CO2 sampling stations, built at University of Copenhagen, for 14C analysis at four locations (East Denmark, Shetland Isles, Faroe Isles and Iceland). The samples were only collected during winter periods of south-easterly winds in an attempt to trace air enriched in fossil-fuel derived CO2 due to combustion of fossil fuels within European countries. In order to study the transport and concentration fields over the region in detail, a three-dimensional Eulerian hemispheric air pollution model has been extended to include the main anthropogenic sources for atmospheric CO2. During the project period (1998–2001) only a few episodes of transport from Central Europe towards NEAR arose, which makes the data set for the evaluation of the method sparse. The analysed samples indicate that the signal for fossil CO2, as expected, is largest (up to 3.7±0.4% fossil CO2) at the Danish location closest to the European emissions areas and much weaker (up to ∼1.5±0.6% fossil CO2) at the most remote location. As the anthropogenic signal is weak in the clean atmosphere over NEAR these numbers will, however, be very sensitive to the assumed background 14CO2 activity and the precision of the measurements. The model simulations include the interplay between the driving processes from the emission into the boundary layer and the following horizontal/vertical mixing and atmospheric transport and are used to analyse the meteorological conditions leading to the observed events of high fossil CO2 over NEAR. This information about the history of the air masses is essential if an observed signal is to be utilised for identifying and quantifying sources for fossil CO2.  相似文献   
95.
This paper analyzes the economic implications of an environmental policy when we account for the life expectancy of heterogeneous agents. In a framework in which everyone suffers from pollution but health status also depends on individual human capital, we find that the economy may be stuck in a trap in which inequality rises steadily, especially when the initial pollution intensity of production is too high. We emphasize that such inequality is in the long run costly for the economy in terms of health and growth. Therefore, we study whether a tax on pollution associated with an investment in pollution abatement can be used to address this situation. We show that a stricter environmental policy may allow the economy to escape from the inequality trap while enhancing the long-term growth rate when the initial inequality in human capital is not too large.  相似文献   
96.
This paper examines Chevron's programme of CSR at a gas field in Bangladesh. Whilst apparently building partnerships in the villages that surround the Bibiyana Gas Field, we suggest that the corporation remains detached from the local population via their community development programmes and employment policies. This contradiction is submerged by ideas and practices within global development discourse which celebrate the disconnection and disengagement of donors via the rhetoric of sustainability. Chiming with development praxis and the neo-liberal values which underscore it by stressing self-reliance, entrepreneurship and ‘helping people to help themselves’, the corporation's Community Engagement Programme does little to meet the demands of local people who hoped for employment and long term investment, a form of connection that is discordant to discourses of self-reliance and sustainability.  相似文献   
97.
This paper investigates the dynamics of upstream linkages development to copper mining in Zambia. The breadth and depth of the local mining supply chain was deeply shaped by policies adopted in the 1990s under the Structural Adjustment Programme. These policies succeeded in attracting much-needed FDI in the mining sector, including Chinese and Indian FDI, but had a negative impact on the level of value-addition undertaken by local suppliers. In the post-privatisation era, the dynamics of the local supply chain suggest that supply firms' upgrading and sales growth were determined by firm ownership and value chain governance. In fact, forward linkages to buyers other than Chinese and Indian mining companies, and backward linkages to parent companies and technology providers were critical in supporting supply firms' success in the mining value chain.  相似文献   
98.
本文在“微宇”环境中研究~(14)C-氯氰菊酯在玉米-土壤-土壤动物相间的质量平衡、吸收、结合残留、迁移和转化规律。实验结果表明,植物通过根部从土壤中吸收少量氯氰菊酯,并通过叶脉输导,但向上输导能力差,无内吸作用。它在土壤中性质较稳定,被动、植物吸收的药剂,在植物体内主要转化为结合态;在动物中则主要为代谢作用。它在土壤中以酯链断裂为主要降解路线,其次为4′-位置上羟化,再经土壤甲基化作用生成4′-甲氧基代谢物。  相似文献   
99.
用~(14)C标记直链烷基苯磺酸盐,(~(14)C-LAS),研究了在由塘泥、水草、鱼、螺蛳和溞构成的室内模拟水生态系统中,LAS的降解规律、在水生生物体内的积累分布及其与在水中降解之间的相互关系.  相似文献   
100.
Prenatal diagnosis of citrullinaemia has been accomplished by three different methods to date: (1) enzyme assay of cultured fetal cells; (2) quantification of citrullirie in amniotic fluid supernatant; and (3) incorporation of [14C]citrulline into protein by cultured fetal cells. Our laboratory has used these methods to perform prenatal diagnosis for 28 fetuses over a 10-year period. More recently, DNA polymorphisms were used for prenatal diagnosis by linkage analysis. Of the 28 fetuses studied, 23 were predicted to be unaffected, four were predicted to be affected, and results were conflicting in one case where [14C]citrulline incorporation erroneously indicated an affected fetus but linkage analysis correctly predicted an unaffected fetus. Because of low levels of enzyme activity in heterozygotes and in certain amniotic fluid cell types, biochemical diagnosis of citrullinaemia is complicated by the risk of false affected results, although [14C]citrulline incorporation is relatively reliable. When informative, linkage analysis is the preferable method for cases with a 25 per cent risk. The risk of false affected results makes prenatal diagnosis for cases with less than 25 per cent risk of questionable value.  相似文献   
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