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491.
根据系统管理原理并在深入研究典型管理体系的基础上,提出要实现我国民航的持续安全,就要构建并不断完善保障持续安全的管理体系,即持续安全保障体系。对该体系的构成要素和运行机制进行了科学的设计,论述了各要素的内涵,对部分要素进行了创新性的诠释。建立了以信息为驱动力的体系的运行机制,并对进一步完善体系提出了建议。该体系的构建与完善将使民航的安全管理逐步实现自我监督和自我完善。 相似文献
492.
Five trace metals (Cu, Zn, Fe, Mn and Cd) were determined in different tissues and organs (muscle, liver, brain, gills, gonads and intestines) of some Tilapia spp. (Oreochromis spp. and Sarotherodon galilaues) collected from two Egyptian Lakes (Edku and Mariut, exposed to different types of pollutants), El-Umum Drain, and from the fishing farm El-Nozha Hydrodrome. Our results indicate that metal accumulation in different organs vary considerably between the same and among different Tilapia spp. There is a preferential accumulation of metals by different organs. Liver is a target organ for Cu accumulation, whereas the brain and flesh tissues clearly accumulate more levels of Zn than the other studied elements. Amongst the studied elements, Cd concentrations in the different organs are the lowest. It was found that edible parts of Tilapia spp. collected from Lake Mariut accumulate the highest levels of the studied elements (Fe, Zn, Mn and Cu for S. galilaues and Cd for Oreochromis niloticus), compared with those in the other studied areas. In general, the levels of Cd (0.0-0.11 ppm), Cu (0.25-1.85 ppm) and Zn (3.58-8.46 ppm) in the edible parts of studied fish cannot be considered as hazardous levels. 相似文献
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谈"动态对等"的缺陷 总被引:1,自引:0,他引:1
谭晓丽 《湖南环境生物职业技术学院学报》2002,8(3):199-202
美国著名翻译理论家Nida提出的"动态对等"原则是对翻译理论界的一大贡献.笔者在承认这个原则的同时,从它概念的几个关键词入手,指出这个概念中几个值得商榷的地方,认为它的理论基础不牢靠,并分析了它所忽视的翻译所涉及的几个要素,由此表明,翻译这种涉及到许多因素的复杂活动不能依靠一种理论来指导. 相似文献
496.
The induction of stress-70 (Hsp70) in the blue mussels Mytilus edulis from southern Baltic after exposure to cadmium, lead and copper, administrated individually and/or as a mixture, was investigated by means of standard Western blotting using a clone 3A3 monoclonal antibody. The general course of the stress-70 induction was found to be similar for all tested metals. It could be characterised by three main features: (1) The induction of stress-70 proteins was only slightly increased at low metal concentration. (2) Strong induction of stress-70 occurred at high concentration of metals. Combination of metals (Cd+Cu) was found to increase the stress-70 level more intensely than related concentrations of singularly applied metals. (3) Five weeks of long depuration had no effect on stress-70 levels. Experiments revealed different induction of stress-70 as a response to cadmium, lead and copper exposure and confirm that the applied technique might serve as a versatile tool to assess invertebrate stress reaction to environmentally relevant heavy metals. 相似文献
497.
A case study of microwave processing of metal hydroxide sediment sludge from printed circuit board manufacturing wash water 总被引:2,自引:0,他引:2
The large quantity of wash water used in the electroplating and etching process in the manufacturing of printed circuit boards (PCBs) contains a high level of heavy metal ions (Cu++, Zn++, Ni++, Cr+++, Pb++). These potentially toxic ions are removed from the wash water effluent through a polyelectrolyte flocculation and hydroxide precipitation process during which a hydroxide sediment sludge rich in metal ions and polymers is generated. This sediment sludge possesses some unique characteristics and properties in terms of composition, fine particle size distribution, high specific surface area, and a tendency to agglomerate after drying. Direct disposal of this classified “special waste” (Department of Environment of Northern Ireland, The Special Waste Regulations, Northern Ireland, 1998) at landfill sites may cause serious soil and underground water pollution through a gradual ionic leaching process. This paper describes an experimental investigation, exploratory in nature, which employs microwave radiation for detoxification of the sediment sludge through microwave heating, drying and metal ion immobilization within the sediment solids. The effectiveness of microwave assisted binding and immobilization of the metal ions within the sediment solids was studied in conjunction with an evaluation of microwave energy efficiency in comparison to the more conventional convective heating and drying processes. Given a sufficient amount of microwave radiation, leaching of Cu2+ and Pb2+ was reduced by 2700% and 1080%, respectively, over a period of 12 weeks, and further leaching was not detectable within six months at simulated local landfill aqueous conditions. This paper also attempts, through experimental observation, to add to the very limited understanding of the complex interactions and binding of free metal ions with the polymeric materials and metal hydroxides under the influence of an electromagnetic field. The high specific surface of the sediment solids and their adsorption properties were further explored and characterized in a study of adsorption of reactive dyes by the microwave processed solids. 相似文献
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T. Sekito Y. Dote K. Onoue H. Sakanakura K. Nakamura 《Waste management (New York, N.Y.)》2014,34(9):1637-1643
Thermal treatment of municipal solid waste (MSW) has become a common practice in waste volume reduction and resource recovery. For the utilization of molten slag for construction materials and metal recovery, it is important to understand the behavior of heavy metals in the melting process. In this study, the correlation between the contents of elements in feed materials and MSW molten slag and their distributions in the ash melting process, including metal residues, are investigated. The hazardous metal contents in the molten slag were significantly related to the contents of metals in the feed materials. Therefore, the separation of products containing these metals in waste materials could be an effective means of producing environmentally safe molten slag with a low hazardous metals content. The distribution ratios of elements in the ash melting process were also determined. The elements Zn and Pb were found to have a distribution ratio of over 60% in fly ash from the melting furnace and the contents of these metals were also high; therefore, Zn and Pb could be potential target metals for recycling from fly ash from the melting furnace. Meanwhile, Cu, Ni, Mo, Sn, and Sb were found to have distribution ratios of over 60% in the metal residue. Therefore, metal residue could be a good resource for these metals, as the contents of Cu, Ni, Mo, Sn, and Sb in metal residue are higher than those in other output materials. 相似文献
500.
为了解辽阳市蔬菜种植和畜禽养殖基地土壤中重金属状况,依据《环境监测分析方法》、《土壤元素的近代分析方法》的要求土壤采样分析。并根据土壤环境质量标准(GB15618-1995),采用Harkanson"潜在生态危害指数法"对土壤中重金属进行生态风险评价。结果表明,在蔬菜种植和畜禽养殖基地所选典型采样点中,重金属含量无超标现象,均属安全范围,对人体及生物无危害。 相似文献