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71.
本文介绍了JB/T 4730.2-2005标准未能涵盖的、适用于在用压力管道的小径管焊口未焊透深度射线检测的一种特殊工艺,并配套设计了特殊的未焊透深度RT对比试块。  相似文献   
72.
Following the Minamata events, an extraordinary number of studies concerning mercury toxicity and human health have been undertaken. Particular attention has been given to the evaluation of the dose-response relationship, i.e., the body burden at which (evaluated through the mercury analyses in blood or hair) the risk of poisoning begins. The results of a comparative study concerning levels of mercury in the hair of fishermen living in small islands who eat seafood more than four times per week show that in two areas only, and only in a few cases in these areas, the mercury in the hair exceeds the limit at which a possible risk could exist. In fact, the limit of 50 mg/g of total mercury in the hair (indicated as the lower limit above which a possible risk could occur) is surpassed by nine fishermen out of a total of 39 at station 1 and by four fishermen out of a total of 26 at station 3. The average value at station 1 is 36.38 mg/g and that at station 3 is 30.31 mg. Many countries have set legal limits of mercury for seafood, but evidently the system does not offer a true protection for man. Only the provisional tolerable weekly intake (PTWI), as repeatedly suggested by WHO, should be considered the best guideline to prevent possibly harmful consequences.  相似文献   
73.
Small mammals are important predators of gypsy moths (Lymantria dispar L.), which are major defoliators of deciduous forests in the northeastern United States. Abundance and habitat relationships of small mammals were studied during summers 1984 and 1985 on forested sites at Moshannon and Rothrock state forests in two physiographic regions of Pennsylvania (Allegheny High Plateaus Province and Valley and Ridge Province, respectively) that varied in potential susceptibility to defoliation. The white-footed mouse (Peromyscus leucopus), which is a major vertebrate predator of gypsy moths, was the most common small mammal on all sites. Of the four common species, northern short-tailed shrews (Blarina brevicauda), southern red-backed voles (Clethrionomys gapperi), and white-footed mice were more abundant at Moshannon compared to Rothrock State Forest, but masked shrews (Sorex cinereus) were more abundant at Rothrock. Elevation was a major factor affecting abundance and distribution of small mammals. Because of the greater abundance of small mammals and more suitable physiographic features at Moshannon compared to Rothrock State Forest, small mammals may be more effective as predators on gypsy moths in the Allegheny High Plateaus than the Valley and Ridge Province of Pennsylvania.  相似文献   
74.
小水电站环境影响评价内容探讨   总被引:1,自引:0,他引:1  
吕庆华  蔡瑢 《四川环境》2003,22(4):67-68,82
小水电站工程环境影响评价按有关规范规定为报告表,但其大纲内容不适合山区小水电站环评。通过总结30余座小水电站环评实践,探讨了小水电站环评基本内容应包括:环境影响分析与预测评价、涉及生态影响因子范围、环境保护措施、公众参与等,从技术角度能满足环保管理部门的审批要求。  相似文献   
75.
本文根据组合模式原理提出了一种用小震调制比(rm)异常区出现高频次的空间异常图,进行强地震中短期预报的方法,简称rs法。该方法在预报强震地点和时间上可望取得较好效果。本文在介绍该方法的基础上,应用该法对3次7级以上大震进行了回顾性检验。  相似文献   
76.
随着经济社会发展水平的不断进步,黑龙江省内主要干流及支流的水质也发生着相应的变化,特别是不断崛起的中小城镇,其产生并排放的污水给水环境带来巨大的压力,急需加快中小城镇污水处理厂建设,削减污染物负荷,改善相关水环境质量。  相似文献   
77.
高层住宅楼已经成为城市建筑中最主要的建筑形式,高层住宅楼的小天井由于具有采光、通风功能又可以节省占地面积而受到开发商和用户的青睐。高层住宅楼采用小天井和外廊结构可能带来的消防安全问题,给城市的消防安全管理增加了不确定因素。采用数值模拟的方法构建了采用小天井与外廊结构的高层住宅楼火灾场景,并开展现场热烟试验,研究了小天井与外廊结构的火灾危险性,对采用防火玻璃分隔方法的可行性进行了论证。研究结果显示,采取使用防火玻璃将小天井和外廊进行分隔的消防措施,不利于外廊烟气的排放和人员疏散。  相似文献   
78.
The long‐term threat of sea‐level rise to coral atoll and reef island communities in Kiribati, Tuvalu and other nations has raised the possibility of international migration. Historical resettlements in the Pacific may provide valuable insight into the long‐term effect of future climate change‐related migration on communities. This study evaluates the challenges faced by Gilbertese people resettled from modern‐day Kiribati to Ghizo in the Solomon Islands by the British colonial administration in the mid‐1900s. Drawing upon field interviews (n = 45) conducted in 2011 and the available historical literature, the study examines the circumstances of the initial failed resettlement in the equatorial Phoenix Islands, the subsequent relocation to Ghizo, and the recent concerns of the Gilbertese in Ghizo. Focus is placed on the struggle to recover from the 2007 tsunami that devastated the unprepared community. The analysis reveals that uncertainty about land tenure (raised by 61% of respondents) persists 60 years after resettlement, and is linked to the ability to recover from the tsunami, tensions with the Melanesian population, concerns over political representation, cultural decline, and education and employment opportunities. The Gilbertese experience can serve as a cautionary tale for policymakers considering mechanisms for facilitating climate change‐related migration.  相似文献   
79.
80.
The article is intended for those who are not safety professionals but are responsible for safety management in a small or medium enterprise (SME) of the process industry. It assumes that a SME is loosely coupled and of low complexity and has a small number of major hazards present in it. The article describes Elementary Safety Management (ESM) as a combination of activities that maintain openness to safety impulses with Elementary Risk Control (ERC). ERC uses four milestones and three rules to get to the necessary and sufficient selection of control measures, which will achieve an acceptable level of risk. To make the ESM scheme as simple as possible, the term causal event is used, which is derived from the term causal factor. Practical Safety Management (PrSM) adds to the ESM the knowledge and skills that a person, who is supposed to design and implement a safety management system, needs. The PrSM procedure is developed to identify optimum controls. The procedure recognizes the unavoidable role of commitment to safety, respects the role of hazard identification, and integrates prospective and retrospective analyses and current knowledge of safety management systems. Examples of application of the procedure are given in the article.  相似文献   
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