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排序方式: 共有1219条查询结果,搜索用时 15 毫秒
911.
In this study,the black carbon (BC) measurements in the atmosphere of Nanjing,China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer.By combining dataset of PM2.5,PM10,CO,NO2,SO2,O3 and meteorological parameters,the temporal variations and the source apportionment of BC were given in this study.The results showed that the PM2.5 mass concentrations decreased in Nanjing,with an average annual rate of va...  相似文献   
912.
旋流板塔钠强化石灰石湿式烟气脱硫研究   总被引:12,自引:0,他引:12  
Sun W  Wu Z  Li Y  Tan T 《环境科学》2002,23(5):105-108
向石灰石脱硫浆液中添加硫酸钠可提高脱硫率。以旋流板塔为吸收器,测定了钠强化石灰石湿式烟气脱硫过程的脱硫率、pH值等随脱硫反应时间的变化情况,对不同pH值范围内的石灰石溶解速率等进行了分析。在与工业操作温度相近的条件下,测定了不同塔板数时的脱硫率和塔压降,计算了平均单板效率。结果表明,增加塔板数,脱硫率提高,而平均单板效率减小,实验条件下,塔板数由1增加到4,液气比为4L/m^3时脱硫率由25.5%提高到48.6%,而平均单板效率则由25.5%下降到15.3%。得出了平均单板效率与塔板数之间的关系式。  相似文献   
913.
基于GT-Power柴油机颗粒捕集器捕集性能的仿真研究   总被引:2,自引:0,他引:2  
利用GT-Power软件建立了柴油机颗粒捕集器(DPF)仿真模型,进行了仿真计算。研究了颗粒捕集器本身结构参数对其捕集效率与压降的影响。结果表明,影响颗粒捕集器捕集效率的主要参数有通道密度(CPSI)、过滤体孔隙率、过滤体微孔直径以及过滤壁厚度;影响颗粒物压降的主要参数有通道密度、过滤体渗透率、过滤体孔隙率以及过滤壁厚度。  相似文献   
914.
采用微波法提取酱油废渣中的总异黄酮,并对酱渣异黄酮提取实验中的微波功率、乙醇浓度、料液比、微波作用时间及提取次数等影响因素进行探讨。在单因素试验的基础上,用正交实验进行酱渣总异黄酮提取工艺参数的优化。正交实验结果表明,微波法提取总异黄酮的最佳工艺条件为:微波功率560 W,乙醇浓度80%,料液比1∶20,微波间歇提取3 m in,在此条件下酱渣总异黄酮浸出率达到90%以上。与传统的热浸提法相比,微波提取法具有提取率高,提取速度快,选择性好及能耗小等特点。  相似文献   
915.
通过对多组源自实验室和工业反应器厌氧颗粒污泥样品主要特征参数的实验室研究和全面的理论分析,对于众多反映颗粒污泥性质的主要参数进行了筛选,在此基础上建立了一组与工业反应器运行状况关系密切且测定方法简便易行、适宜在生产实践中应用的颗粒污泥品质评价参数。所建参数体系能够较好地反映生产操作条件下厌氧反应器的运行状况,并能为高效厌氧反应器的运行控制提供理论依据。  相似文献   
916.
In late August 1994, an outbreak of human pneumonic/bubonic plague was reported in Surat, India. During the epidemic, large amounts of pesticides, such as benzene-hexachloride (BHC) and other organochlorinated compounds were used to control the vector that might have transmitted the plague. In order to evaluate the extent of contamination, both environmental samples (9 water samples and 4 soil samples) and biological samples (5 blood and urine samples) were collected and analyzed for organochlorine residues. Samples were analyzed after hexane extraction by gas chromatography equipped with electron capture detector (GC-ECD), using a PTE-5 capillary column. The results showed that the levels of 1,1-(2,2-dichloroethenylidene)-bis[4-chlorobenzene] (DDE), a major metabolite of DDT, were low in environmental samples (water, soil), while BHC levels were relatively high in one of the water sample as well as two soil samples. The BHC and DDE levels in the biological samples were not higher than those reported earlier from India, except for serum DDE. Further studies are needed to evaluate the effect of long-term exposure as the present study was based on limited samples.  相似文献   
917.
Climate change exposes economic systems to numerous risks, including reduced agricultural production and electric power supply shortages. The interdependent nature of economic systems causes disruptions in any sector to cascade to other sectors via forward and backward linkages. This work develops an optimization model with which allocation of scarce goods or resources can be optimized; the model uses an overall index of satisfaction of fuzzy economic output goals under conditions of scarcity caused by climatic disruptions. The proposed model includes a vulnerability measure that integrates information elicited from expert judgment. A case study based on a scenario of drought-induced electricity shortage in the Philippine economy is examined. Results show that trade, transportation and service-oriented industries suffer losses in gross domestic product in the Philippine case.  相似文献   
918.
Nature reserves (NR) are the cornerstone of biodiversity conservation. Over the past 60 years, the rapid expansion of NRs in China, one of the world's megadiverse countries, has played a critical role in slowing biodiversity loss. We examined the changes in the number and area of China's NRs from 1956 to 2014 and analyzed the effect of economic development on the expansion of China's NRs from 2005 to 2014 with linear models. Despite a continuing increase in the number of NRs, the total area of China's NRs decreased by 3% from 2007 to 2014. This loss resulted from downsizing and degazettement of existing NRs and a slowdown in the establishment of new ones. Nature reserves in regions with rapid economic development exhibited a greater decrease in area, suggesting that downsizing and degazettement of NRs are closely related to the intensifying competition between economic growth and conservation. For example, boundary adjustments to national NRs, the most strictly protected NRs, along the coast of China's Yellow Sea, a global biodiversity hotspot with a fast-growing economy, resulted in the loss of one-third of the total area. One of the most important ecosystems in these NRs, tidal wetlands, decreased by 27.8% because of boundary adjustments and by 25.2% because of land reclamation. Our results suggest conservation achievement, in terms of both area and quality, are declining at least in some regions in the Chinese NR estate. Although the designation of protected areas that are primarily managed for sustainable use has increased rapidly in recent years in China, we propose that NRs with biodiversity conservation as their main function should not be replaced or weakened.  相似文献   
919.
Wang  Chunlei  Yang  Ye  Wu  Nanxiang  Gao  Ming  Tan  Yufeng 《Environmental Chemistry Letters》2019,17(4):1693-1706
Environmental Chemistry Letters - Co-occurrence of pyrethroid insecticides and heavy metals in the environment may produce combined toxic effects that are higher or lower than toxic...  相似文献   
920.
水丝蚓生物扰动对沉积物磷释放的影响   总被引:4,自引:0,他引:4  
研究了不同投放密度和不同环境条件下水丝蚓的生物扰动对沉积物磷释放的影响.研究表明,水丝蚓的生物扰动作用对沉积物磷释放有明显的促进作用,与未投放水丝蚓的空白组相比,当水丝蚓密度为1 ind./cm2和2 ind./cm2时,上覆水中总磷的平均浓度分别提高了190%和230%.温度的提高,会加大水丝蚓生物扰动对磷释放的影响...  相似文献   
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