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801.
在现代安全管理中,关于安全事故预防的方法和理论有很多.随着当今越来越多的企业建立和运行HSE管理体系,运用管理体系的方法和原理达到安全事故预防的目的,已日渐成为安全管理领域中的重要趋势.现结合HSE管理体系标准的相关要求,借鉴安全领域中众所熟知的"安全金字塔"法则,来浅淡细节管理在安全事故预防中的价值. 相似文献
802.
Comparison of catalytic activity of two platinised TiO2 films towards the oxidation of organic pollutants 总被引:2,自引:0,他引:2
Two types of platinised TiO2 films, i.e., Pt-TiO2/ITO and Pt(TiO2)/ITO, were prepared by a procedure of dip-coating and subsequent photo-deposition, and photo-deposition and subsequent dip-coating, respectively. They were well characterized by DRS, XRD spectra, SEM microscopy and photoelectrochemical measurement. Their photocatalytic, dark catalytic and photoelectrocatalytic activities were investigated using formic acid as a model organic pollutants. Compared with pure TiO2/ITO film, the photocatalytic activity of the platinised TiO2 films were apparently improved. However, the improvement was considerably dependent on the preparation method of these films. Pt-TiO2/ITO not only possessed higher photocatalytic activity but also showed a dark catalytic activity towards HCOOH degradation. As a sequence, it was first emphasized that the dark catalytic effect of Pt-TiO2/ITO was partly responsible for degradation of formic acid in the photocatalytic oxidation process. Although the Pt(TiO2)/ITO film does not exhibit the dark catalytic activity, its photocatalytic degradation efficiencies towards HCOOH are higher than that of Pt-TiO2/ITO film. Therefore, in view of enhanced photocatalytic activity, the Pt(TiO2)/ITO was more favored than Pt-TiO2/ITO film. 相似文献
803.
The speciation and extent of migration of adsorbed Pb and Cd in natural surface coatings (NSCs) were investigated using sequential extraction procedure to provide an understanding of distribution of the adsorbed Pb and Cd. Extractions were conducted on NSCs before and after Pb and Cd adsorption treatment under controlled laboratory conditions with initial Pb and Cd concentrations ranging from 0.2-2.5 mol/l. The Langmuir adsorption isotherms were applied to estimate equilibrium coefficients of Pb and Cd adsorption to NSCs components. The results showed that 58.50% of adsorbed Pb in average existed in tightly adsorbed form, and the remaining Pb was mostly present as solid oxides/hydroxides (34.00%) and exchangeable and soluble form (7.50%) in NSCs, respectively. Large amount of adsorbed Cd (70.51% in average) was present in exchangeable and soluble form, following a decreasing order in tightly adsorbed form (18.61%), solid oxides/hydroxides (9.87%), and easily oxidizable solids/compounds (1.01%), respectively. No Cd was found in strongly held oxides and precipitates. Compared to the distribution of adsorbed Pb in NSCs, Cd distribution showed that less migration of Cd from exchangeable and soluble form to solid oxides/hydroxides after adsorbed to NSCs, indicating fewer sites for Cd to adsorb to NSCs and less affinity of Cd to the NSCs. These percent distributions of metals provided an additional interpretation to that Pb adsorption to the NSCs greater than that of Cd, less retention of Cd than that of Pb and less roles attributed for Pb/Cd adsorption by organic materials in NSCs, which were observed based on the selective extraction techniques in the independent investigations. 相似文献
804.
Influence of cadmium on antioxidant capacity and four microelement concentrations in tomato seedlings (Lycopersicon esculentum) 总被引:12,自引:0,他引:12
Tomato (Lycopersicon esculentum) seedlings were grown in four cadmium (Cd) levels of 0-10 microM in a hydroponic system to analyze the antioxidative enzymes, Cd concentration in the plants, and the interaction between Cd and four microelements. The results showed that there was a significant increase in malondialdehyde (MDA) concentration, and superoxide dismutase (SOD) and peroxidase (POD) activities in the plants subjected to 1-10 microM Cd. This indicates that Cd stress induces an oxidative stress response in tomato plants, characterized by an accumulation of MDA and increase in activities of SOD and POD. Root, stem and leaf Cd concentrations increased with its exposure Cd level, and the highest Cd concentration occurred in roots, followed by leaves and stems. A concentration- and tissue-dependent response was found in the four microelement concentrations to Cd stress in the tomato leaves, stems and roots. Regression analysis showed that there was a significantly negative correlation between Cd and Mn, implying the antagonistic effect of Cd on Mn absorption and translocation. The correlation between Cd and Zn, Cu and Fe were inconsistent among leaves, stems and roots. 相似文献
805.
Cu and Zn adsorption onto non-residual and residual components in the natural surface coatings samples (NSCSs) in the Songhua River, China 总被引:1,自引:0,他引:1
Natural surface coatings samples (NSCSs) from the surface of river shingles were employed to investigate the roles of non-residual and residual components of the NSCSs in controlling Cu and Zn adsorption via the selective extraction techniques and statistical analysis. The results indicate that the greatest contribution to metals adsorption on a molar basis was from Mn oxides in the non-residual fraction. Metals adsorption capacities of Mn oxides exceeded those of Fe oxides by one order of magnitude, fewer roles were found attributing to adsorption by organic materials (OM), and the estimated contribution of the residual fraction to metals adsorption was insignificant. These results implied that Mn oxides were the most important component in controlling heavy metals in aquatic environments. Experiments with Cu and Zn adsorption measured together showed that Cu severely interfered with Zn adsorption to the NSCSs and vice versa under the conditions of the two coexisted ions adsorption. 相似文献
806.
Effects of metsulfuron-methyl on the microbial population and enzyme activities in wheat rhizosphere soil 总被引:1,自引:0,他引:1
He YH Shen DS Fang CR He R Zhu YM 《Journal of environmental science and health. Part. B》2006,41(3):269-284
The effects of metsulfuron-methyl, a sulfonylurea herbicide, on the wheat soil microorganisms were evaluated by the methods of microbial inoculation culture, and the activities of three enzymes were measured using the colorimetric method. The tolerant microorganisms that can resist 500 microg x g(-1) metsulfuron-methyl in the counting culture medium were studied specially. Metsulfuron-methyl distinctly inhibited the common aerobic heterotriphic bacteria, but the effects on common fungi and common actinomycete were not evident. In the meantime, the number of tolerant fungi increased greatly in the rhizosphere after the application of metsulfuron-methyl in contrast to the significant decrease of the amount of tolerant actinomycete. It indicates that fungi might turn into the dominant microbial type and actinomycete is the sensitive factor in the soil polluted by sulfonylurea residues. The population of aromatic compounds-decomposing bacteria, aerobic azotobacter, and nitrite bacteria all increased in the earlier period, but the aerobic azotobacter decreased rapidly in number 30 days later, and the amount of nitrite bacteria also showed a temporary decrease with time 15 days later. However, the denitrifying bacteria just began to increase significantly after the crops had grown for 50 days. The amount of sulfur-oxidizing bacteria gradually decreased with the growth of crops, and so were the sulfate-reducing bacteria after metsulfuron-methyl application. To all types of microorganisms, there were more microbes in rhizosphere samples than those in nonrhizosphere except aerobic azotobacter. It means the growth of wheat root system can stimulate the growth of most microorganisms. The activities of hydrogen peroxidase and polyphenol oxidase in soil samples after metsulfuron-methyl application were notably lower than those in the control, and the difference of the activities between the samples of rhizosphere and nonrhizosphere was evident. On the contrary, the activity of dehydrogenase was not inhibited by the application of metsulfuron-methyl, and the rhizosphere effect was not obvious either. 相似文献
807.
针对煤层开采后常出现矿压显现剧烈、煤岩透气性增大和地表下沉等问题,利用二维相似模拟试验研究综放工作面覆岩破坏特征并通过分形理论表征裂隙演化规律.试验结果表明:煤层基本顶初次来压步距为78 m,周期来压步距为24 m;煤层采动裂隙发育,距煤层顶板超过35 m;煤层开采后形成的覆岩裂隙具有分形特征,其分形维数随工作面的推进... 相似文献
808.
High levels of corporate environmental information disclosure (EID) have become pressing issues due to environmental protection around the world. Corporate EID refers to disclose their information on activities related to the natural environment, environmental protection and use of resource. Emerging economies in developing countries seem to face a formidable task for promoting corporate EID. Based on data of corporate EID for 871 listed manufacturing companies in China, this paper examines the status of corporate EID. The significant difference of selectively disclosing their environmental information for the listed companies is investigated. The relations among the level of EID, industrial sector, company size, and company ownership are also explored. Surprisingly, the result reveals the inverse relationship between the marketization level and corporate EID. 相似文献
809.
810.