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121.
重金属离子对生物污泥活性的抑制 总被引:6,自引:0,他引:6
研究了工业废水中常见的Cd~(2+)、Ni~(2+)、Cr~(6+)、Zn~(2+)、Cu~(2+)、Al~(3+)和Fe~(3+)七种重金属离子对生物污泥的抑制作用。发现其抑制的机理各不相同,前五种为不可逆抑制,污泥经过洗涤,活性不易恢复,而后二种为可逆抑制,污泥洗涤后,活性能基本恢复。试验还发现,几种金属离子同时存在时,抑制性比单一金属离子强。金属离子会在污泥中积聚,因此,即使废水中浓度很低,长期接触也会使生物污泥活性降低。 相似文献
122.
Yin Chengqing 《环境科学学报(英文版)》1989,1(2):23-28
Yuxi River-Chaohu Lake water suffers greatly from the ecological problems of eutrophication, high turbidity, organic pollution, disappearance of littoral macrophyte, bank erosion and reduction of economic fishery products. With Micro-cystis dominant, it is a degenerated and weak ecosystem. Its vicious cycling is caused by too much nutrient load, high spring water level and improper management of the water. The point sources of pollution from cities and industries contribute more than 50% of nutrient load. Soil erosion and fertilizer loss from late rice fields are important factors in non-point nutrient load. The disappearing littoral zone can neither give enough protection for the bank nor provide proper habitats for the biota. The feasibility of " ecological water level proposal" and means to reduce nutrient load are discussed to improve the habitat environment for both the nature and human being. 相似文献
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125.
此文主要介绍了几种较实用和新发展的机械零件的粉末冶金成形方法,包括Olivetti法,螺旋形状零件成形法,粉末注射成形,组合烧结成形,粉末锻造和旋转锻造。 相似文献
126.
Li Xiuzhen Wu Kunjun Gong Peiyu Institute of Zoology Academia Sinica Beijing China 《环境科学学报(英文版)》1990,(4)
Population life tables of the army worm, Mythimna separata, were constructed and nutritional parameters of food for the larvae were examined at 5 temperatures from 16℃ to 32℃. The temperature suitable for growth and reproduction of the insect ranged from 20℃ to 28℃ with the optimum of 24℃. Their survivalship and fecundity were much poorer at 32℃ than at 16℃. Indices of population trend of the insect at these temperatures could well fitted with the parabolic curve which theoretically indicated that the population density would multiply by some 660 after one generation circle at the optimal temperature, 22.6℃, and it would decline at temperatures higher than 32.9℃ or lower than 12.3℃. Larval food intake and their AD tended to go up while their ECI and ECD to go down with a rise in temperature. These alterations in population size and feeding behavior caused by temperature would exert an important effect on their damage to crops. 相似文献
127.
针对具体工件对根限变形程度下纯铝反挤压的变形力进行研究,分析了各种计算方法的适用范围,并与工艺试验的实测值进行了比较. 相似文献
128.
FreradicaloxidationofspentradioactiveorganicsolventJiXiaoyuan,ZhaoBinInstituteofNuclearEnergyTechnology,TsinghuaUniversity,Be... 相似文献
129.
QuantitativemodelforspeciesdistributionofhydroxypolyaluminumchlorideFengLi,LuanZhaokun,TangHongxiaoResearchCenterforEcoEnvir... 相似文献
130.
A procedure for analysis of organic pollutants in coal gasification wastewater was developed, including a series extraction steps at different pH, followed by LC separation or resin adsorption, then analyzed by GC or GC/MS. More than 200 organic pollutants in 22 categories were determined. CH2CL2 extraction at NaHCO3 presence was used to separate carboxylic acids with phenolic compounds in aqueous. Derivatization with acetic anhydride was used for analyses of mono-, di-, poly-hydroxyl phenolic compounds. 21 mono-hydroxyl phenols and 13 di-hydroxyl phenols were determined from the coai gasification wastewater samples. Derivatization with BF3-CH3OH was used for analysis of carboxylic acid. 17 mono-carboxyl, 4 di-carboxyl acids and 6 aromatic acids were determined from coal gasification wastewater samples. 相似文献