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891.
为了解决飞机火灾事故易发问题、降低事故发生率,以巡航过程中客机发生火灾事故为情境,提出事故树分析法和模糊层次分析法相结合的研究方法。绘制树形图研究人为、机械、环境和管理等方面导致飞机火灾事故发生的途径,构建飞机火灾事故指标体系,结构重要度对指标赋值得出权重值顺序,结果表明:安检和安全培训对飞机火灾事故发生影响最大,空气影响次之,机械故障影响最小。因此,最有效的飞机火灾事故预防途径应从可燃物控制方面着手。 相似文献
892.
893.
894.
民航维修单位质量控制员胜任力模型研究 总被引:4,自引:0,他引:4
民航维修单位质量控制员的胜任力是维修单位质量控制员实施维修质量控制工作的关键因素,也是判定维修质量控制员工作绩效优异与否的重要指标.采取理论与实践相结合的研究方法,采取行为事件访谈法对维修质量控制员进行访谈,收集其胜任力信息,依据实证调研的结果及相关文献研究成果,建立了包含4个一级胜任力指标和17个二级胜任力指标的维修单位质量控制员胜任力模型.其中得到9项维修单位质量控制员核心胜任力模型,运用超级决策软件(SD)对建立的模型准确性进行验证. 相似文献
895.
Antimony speciation and contamination of waters in the Xikuangshan antimony mining and smelting area,China 总被引:3,自引:0,他引:3
Faye Liu X. Chris Le Anthony McKnight-Whitford Yunlong Xia Fengchang Wu Erika Elswick Claudia C. Johnson Chen Zhu 《Environmental geochemistry and health》2010,32(5):401-413
Water samples from Xikuangshan (China), the world largest antimony (Sb) mine with a Sb mining and smelting history of more
than 200 years, were analyzed. These water samples ranged from stream water in the vicinity of the mining and smelting area
that received seepage from ore residues to the underground mine-pit drainage. The concentrations of total Sb, Sb (III) and
Sb (V) of the samples were determined by HPLC-ICP-MS. In addition, water pH and concentrations of major cations and anions
were analyzed. All 18 samples demonstrated total Sb concentrations with ppm levels from 0.33 ppm to 11.4 ppm, which is two
to three orders of magnitude higher compared to the typical concentration of dissolved Sb in unpolluted rivers (less than
1 ppb). This is probably the first time that such high Sb contents have been documented with complete environmental information.
Distribution of total Sb and Sb species was investigated, taking into account the respective local environment (in the mining
area or close to the smelter, etc.). Sb (V) was the predominant valence in all 18 samples. Only trace levels of Sb (III) were
detected in 4 of the 18 samples. Geochemical speciation modeling showed the dominant species was Sb(OH)6−. It is also probably the first time that such high Sb contents have been documented in the natural environment with Sb speciation
distribution information. Several potential oxidation pathways are also discussed that might have facilitated the oxidation
of Sb (III) in the natural environment. Signs of intoxication were observed among local mine workers with extensive exposure
to different forms of Sb for a long period of time. 相似文献
896.
897.
从湿地现状、服务功能和外环境影响3方面构建了城镇区域内湿地生态健康评价指标体系,采用层次分析法(AHP)和模糊综合评价法,对广汉鸭子河湿地这一城镇区域内河滩型湿地生态系统健康状况进行评价。结果表明,在广汉市城市化进程中,该湿地的生态系统受到了一定程度的影响,就总体而言,湿地生态系统结构完整,基本功能依然具备,但栖息地功能有一定的退化,在整体上属于亚健康状态。根据评价结果及退化成因分析,提出了相应的恢复措施,对广汉市城市化进程中鸭子河湿地的保护提供了重要的决策依据,对同类型的湿地保护具有指导意义和借鉴价值。 相似文献
898.
样品前处理是有机污染物应急监测中的重要环节。介绍了热分离进样杆、分散液液微萃取、搅拌棒吸附萃取、固相微萃取等适合于有机污染物应急监测的样品前处理技术,并概述了它们在环境分析领域的应用进展。如何将这些前处理技术与自身拥有的应急监测设备有效结合是环境监测技术人员亟待解决的问题。 相似文献
899.
Junqiang Xia Zhengbing Wang Yanping Wang Xin Yu 《Journal of the American Water Resources Association》2013,49(1):114-131
Xia, Junqiang, Zhengbing Wang, Yanping Wang, and Xin Yu, 2012. Comparison of Morphodynamic Models for the Lower Yellow River. Journal of the American Water Resources Association (JAWRA) 1‐18. DOI: 10.1111/jawr.12002 Abstract: Significant channel adjustments often occur during flood seasons in the Lower Yellow River (LYR), and it is a challenging work to accurately simulate the morphodynamic processes in the LYR using numerical models. A comparison of two morphodynamic models (Delft3D and 2DLLCDM) for the LYR is presented herein to identify critical improvements for these models. The concepts of these models are first compared with each other. The models were then used to simulate the processes of flood routing, sediment transport, and morphological changes occurring in a braided reach of the LYR. The differences were investigated between the simulated results from these models and corresponding field measurements, and the results indicate that: (1) the hydrodynamic processes calculated by both models agree closely with the measurements if an appropriate Manning’s roughness coefficient is used; (2) the concentrations of suspended load at the downstream boundary calculated by the models agree reasonably with the observed data; and (3) the predicted cross‐sectional profiles obtained from these models do not correspond well with the measurements. Based on these findings, the weak aspects of the models are clarified, and three critical improvements are recommended, including: (1) the development of roughness predictor; (2) the refinement of graded sediment transport capacity formulation; and (3) the consideration of bank erosion module. These improvements need to be implemented in the future. 相似文献
900.
Mengtian Li Ge Song Ruiping Liu Xia Huang Huijuan Liu 《Frontiers of Environmental Science & Engineering》2022,16(6):70