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981.
本文研究了有机磷农药甲基1605和毒死蜱对~1O_2探针性物质二乙基二硫酸(DES)、萜品烯(α-terp)及ROO和RO探针性物质2.6-二叔醒基-4-甲基苯酚(BHT)和1,2,3,4-四氢萘(tetra)光降解的敏化作用.结果表明基态氧直接参与了DES和α-terp的光解;在甲基1605的作用下,1/K_(exptl)与[α-terp]的关系表明,α-terp的降解不为~1O_2历程;同时BHT和tetra的敏化降解说明ROO的量子产率为~1O_2量子产率的5倍;对氯氰菊酯的光敏降解产物的检测表明,在甲基1605存在下,产物仍然以~3O_2氧化产物为主. 相似文献
982.
湖南五味子科植物有2属11种2变种,分布于31个县,多生长在海拔600—1200m的山地灌丛或林中。本文依据湖南五味子科植物的地理分布,结合系统分类,植物区系和土壤资料,经分析和推论得知:1.湖南五味子科植物种质资源丰富,以中国特有种为主,它们与毗邻省区的关系密切。2.湖南五味子科植物区系表现为多种区系成分的过渡与汇集,即华南、华东、华中和滇黔桂4个区系成分的交汇、混杂和过渡。3.湖南五味子科植物的多数种类是从湖南以西地区迁移扩散而来,有的种类是从本省西北或西南以外地区而来,极少数植物在本省西南地区及其周边省区分化形成。4.湘西北至湘西南地区是湖南五味子科植物的现代分布中心,现代分化中心是湘西南地区。 相似文献
983.
Xiaoyan Zhou Xianghua Wen Yan Feng 《Frontiers of Environmental Science & Engineering》2007,1(1):89-94
The present work studied the influence of glucose feeding on the ligninolytic enzyme production of Phanerochaete chrysosporium in a nitrogen-limited (C/N ratio is 56/8.8 mmol/L) medium. Several sets of shaking flask experiments were conducted. The results showed that 2 g/L glucose feeding on the first day of the culture (24 h after the inoculation) simulated both fungal biomass growth and enzyme production. The manganese peroxidase (MnP) activity was 2.5 times greater than that produced in cultures without glucose feeding. Furthermore, the glucose feeding mode in fed-batch culture was also investigated. Compared to cultures with glucose feeding every 48 h, cultures with glucose feeding of 1.5 g/L (final concentration) every 24 h produced more enzymes. The peak and total yield of MnP activity were 2.7 and 3 times greater compared to the contrast culture, respectively, and the enzyme was kept stable for 4 days with an activity of over 200 U/L. 相似文献
984.
985.
处理啤酒废水的厌氧流化床操作特性的研究 总被引:1,自引:0,他引:1
试验表明,自制厌氧流化床(AFB)反应器对温度的变化、上升流速等环境的变化都具备良好的稳定性.它的处理温度控制在30±2℃范围,上升表观流速控制为19.1 m/h左右,回流比控制为8:1,水力停留时间在6.9 h左右,废水COD去除率可达80%以上.该AFB反应器能够承受高达30.65 kg COD/m3·d的有机容积负荷,其COD去除率也达到了73%~81%,产气速率系数为0.55~0.612 m2/kg COD.同时,也对实验中出现的偏析现象进行了分析. 相似文献
986.
Water from the three reservoirs, Min-ter, Li-yu-ten and Yun-ho-shen, was examined for concentration of chlorophyll a, ultraviolet absorption (UV(254)), fluorescence intensity (FI), concentration of dissolved organic carbon (DOC), and fractionation of dissolved molecules by molecular weight. The water samples were collected over the change from spring to summer (May to July but before the typhoon season) when the water temperature and extent of eutrophication increase. Analytical results indicate that the concentration of DOC is proportional to the concentration of chlorophyll a, but not to the values of UV(254) and FI. Therefore, eutrophication, extraneous contaminants of small molecules, and the extracellular products of algae cause an increase in DOC, but a decrease in the proportion of large organic molecules such as of humic substances. The fraction of DOC with a molecular weight of less than 5000 Da increases with the concentration of chlorophyll a. All these data suggest that changes in the quality of water after eutrophication make the treatment of drinking water more difficult. The method of enhanced coagulation was recently developed for removing DOC. However, the results of this paper demonstrate that the efficiency of DOC removal falls as the degree of eutrophication increases. When the percentage of DOC with small molecules excreted by algae increased by 1%, the efficiency of DOC removal decreased by approximately 1%, implying that enhanced coagulation are not able to remove the DOC excreted by the algae during eutrophication, and resulting an increased concentration of trihalomethanes formation in water disinfections process. 相似文献
987.
988.
A dynamic couple-column high performance liquid chromatographic technique was used to determine the aqueous solubilities of 9 nitrated polycyclic aromatic hydrocarbons. A linear relationship between aqueous solubilities and molecular connectivity indices of these compounds has been established. According to this relationship, the aqueous solubilities of 18 other nitrated polycyclic aromatic hydrocarbons were estimated. 相似文献
989.
乙酰丙酮分光光度法测定新装修住宅室内空气中的甲醛 总被引:1,自引:0,他引:1
对乙酰丙酮分光光度法测定室内空气中甲醛的方法进行了优化,同时对北京市11户部分新装修居室室内空气中的甲醛含量进行了测定.结果表明,有8户住宅超过了我国室内空气质量标准GB/T18883-2002规定的甲醛最高容许质量浓度0.10 mg/m3. 相似文献
990.