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181.
本文通过腐蚀失重试验、腐蚀产物分析和交流阻抗谱研究了Q345R在不用的微量的两种小分子有机酸(甲酸和乙酸)中的常温25℃和液相高温85℃中腐蚀行为.根据试验结果可知,随着浓度的逐渐升高,Q345R在两种小分子有机酸腐蚀速率均有所升高,腐蚀产物逐渐增厚,腐蚀形貌未发生明显变化.根据电化学试验结果,在25℃环境温度下,小分子有机酸对Q345R的腐蚀剧烈程度随时间明显降低,并且表面吸附作用明显减弱.在85℃环境温度下,小分子有机酸对Q345R的腐蚀剧烈程度随时间变化不大,反应行为也未发生明显的变化.这说明在较高的温度下,随着反应激活能提高,扩散条件并非控制腐蚀反应的最主要因素,腐蚀行为也与较低环境温度下产生显著的区别. 相似文献
182.
为更好地开展煤矿安全文化建设工作,采用安全文化在线分析系统对我国60家煤矿企业的安全文化建设水平进行分析;利用SPSS 22.0软件分析不同人员类别、性别、工龄、文化程度对安全文化得分的影响;对煤矿安全文化建设中部分得分较低的安全文化元素给出整改建议。结果表明:得分低于60分的元素是安全业绩对待方式、总体安全期望;安全文化得分与人员类别、工龄、文化程度显著相关,与性别无显著相关性;煤矿企业应进行针对性培训,并设计和建设合理的安全理念条目、良好的安全理念载体及完善的安全文化培训体系。 相似文献
183.
The effect of 24-epibrassinolide seed soaking on imidacloprid residues in green pods and mature seeds of Brassica juncea L. plants was investigated. The activities of the antioxidative enzymes glutathione-S-transferase, glutathione peroxidase, glutathione reductase, ascorbate peroxidase and guaiacol peroxidase, and the content of glutathione were determined. Imidacloprid residues in green pods were analyzed and quantified by gas chromatography-mass spectrometry, revealing that 24-epibrassinolide treatment resulted in a decrease of residues by almost 30%. In mature seeds, no pesticide residues were detected. Activities of all the antioxidative enzymes and glutathione content were found to be high in plants grown in soil amended with 300 mg imidacloprid kg?1 soil, but pre-soaking with 100 nmol L?1 24-epibrassinolide further enhanced the activities of all these enzymes and the glutathione content. 相似文献
184.
The 2,3,3′,4,4′,5,5′-heptachloro-1′-methyl-1,2′-bipyrrole (Q1, MBP-79) and further halogenated 1′-methyl-1,2′-bipyrroles (MBPs) are a class of marine natural products repeatedly detected in seafood and marine mammals from all over the world. Only Q1 is currently commercially available as reference standard and the full synthesis of mixed brominated-chlorinated compound is rather complicated. For this reason, synthetic Q1 (240 mg) was transferred into bromine-containing MBPs by UV-irradiation in the presence of bromine. Bromine, which rapidly vanished from the solutions, was re-newed during the reaction in order to generate higher amounts of Br-containing MBPs. A total of ∼150 mg Q1 was transferred after ∼10 min irradiation with high amounts of Br2 to give 30.5 mg BrCl6-MBPs along with lower proportions of Br2Cl5-, Br3Cl4-, Br4Cl3- and traces of Br5Cl2-MBPs. Longer UV-irradiation in the presence of Br2 even allowed for the detection of Br6Cl-MBPs and traces of Br7-MBP. However, this reaction also provided some unknown by-products. A sample stored in the dark and later in in-door light (no UV irradiation) also eliminated Q1 after 76 d in favour of heptahalogenated MBPs with up to three bromine substituents. The irradiation products were separated on silica, and fractions containing only Q1 and BrCl6-MBPs were then further fractionated by non-aqueous RP-HPLC. A pure isolate of the major BrCl6-MBP (∼1.5 mg) was characterized by GC/MS and 13C NMR to be 2-bromo-3,3′,4,4′,5,5′-hexachloro-1-methyl-1,2′-bipyrrole (Br-MBP-75). Partial GC enantioseparation of the axially chiral Br-MBP-75 was achieved on a β-PMCD column. A full enantioseparation was managed by enantioselective HPLC using a NUCLEOCEL DELTA S column. Low amounts of pure BrCl6-MBP enantiomers could be trapped. 相似文献
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186.
Technological choices are multi-dimensional and thus one needs a multi-dimensional methodology to identify best available techniques. Moreover, in the presence of environmental externalities generated by productive activities, ‘best’ available techniques should be best from Society's point of view, not only in terms of private interests. In this paper we present a modeling framework based on methodologies appropriate to serve these two purposes, namely linear programming and internalization of external costs. We develop it as an operational decision tool, of interest for both firms and regulators, and we apply it to a plant in the lime industry. We show why, in this context, there is in general not a single best available technique (BAT), but well a best combination of available techniques to be used (BCAT). 相似文献
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188.
This paper examines Chevron's programme of CSR at a gas field in Bangladesh. Whilst apparently building partnerships in the villages that surround the Bibiyana Gas Field, we suggest that the corporation remains detached from the local population via their community development programmes and employment policies. This contradiction is submerged by ideas and practices within global development discourse which celebrate the disconnection and disengagement of donors via the rhetoric of sustainability. Chiming with development praxis and the neo-liberal values which underscore it by stressing self-reliance, entrepreneurship and ‘helping people to help themselves’, the corporation's Community Engagement Programme does little to meet the demands of local people who hoped for employment and long term investment, a form of connection that is discordant to discourses of self-reliance and sustainability. 相似文献
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190.
Zhiming Cai Richard H. Clarke Bartek A. Glowacki William J. Nuttall Nick Ward 《Resources Policy》2010
Recent, pre-downturn, disturbance in the global helium market can be traced to the tight supply–demand position, which characterizes today’s changing helium supply structure. A detailed System Dynamics model provides fresh insight into the helium question and suggests a production path that is closely associated with future natural gas production. Venting of un-extracted helium to the atmosphere remains a central issue. The model indicates that improving resource exploitation strategies might extend a production plateau that emerges in the 2030s. Substitution will result in more helium being vented. To mitigate this, the industry needs to ensure security of supply (particularly after the Bureau of Land Management reserve is sold). 相似文献