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251.
针对地质勘探行业粉尘作业的多样性 ,以及呼吸性粉尘检测结果作为指标 ,提出了对现有不同防尘措施的呼吸性粉尘控制效果评价的几种方法 ,并进行了初步评价 相似文献
252.
About 500 samples of coal, pyritic coal balls, pyritic gangue and coal seam gangue were collected from different coal basins and geologic periods of coal formation to determine the arsenic (As) content and distribution pattern in China. The Permian-Carboniferous and Jurassic coals in the North China Plate and Northwest China account for nearly 85% of total Chinese coal reserves and data showed that As content ranged from 0.1 to 94?mg?kg?1, with the majority between 1 and 14.9?mg?kg?1. The As content of some Late Permian coals in Southwest Guizhou Province and stone coal in the South Qinling Mountain area were exceedingly high (30–534?mg?kg?1), but the majority of coal in the Southwest Guizhou Province contained low to medium amounts. Only the coals, which are situated in or near igneous rocks and are not considered a part of Chinese coal reserves, possessed unusually high As content (>30?mg?kg?1). Arsenic was also concentrated in pyritic coal balls and the pyritic gangue of the coal seam with values ranging from 21.5 to 142.46?mg?kg?1 and an average of 69?mg?kg?1 in Shaanxi and 78?mg?kg?1 in Shandong. Arsenic contents in coal gangue in the Northwest and North China Plate is about 0.2–15?mg?kg?1, a little lower than coals in the same seam. Washing gangue (waste from coal washing) generally contained more As than coal, because the washed gangue has more pyrite than the natural gangue (black shale). Washing coal reduced the content of the pyritic sulfur, heavy metals and As. Based on amounts of coal used with different As content in Chinese coal reserves, the average As content of Chinese coals is about 4.5?mg?kg?1. 相似文献
253.
254.
石油天然气勘探开发的应急预案 总被引:4,自引:0,他引:4
针对目前应急预案编制与应急管理中存在的问题.阐述了石油、天然气开发应急预案编制与应急管理的必要性.并结合含硫高压油气井井喷失控应急预案的编制,对应急预案的定义、油气勘探开发应急预案编制的原则和要求、编制内容以及应急管理等问题进行了阐述。 相似文献
255.
Since 1985, the US Environmental Protection Agency (EPA) has conducted monitoring studies to determine the transport, fate, and effects of sewage sludge dumped at the 106-Mile Deepwater Municipal Sludge Dump Site (106-Mile Site). This paper describes EPA's 106-Mile Site monitoring activities and the results from six oceanographic surveys of the Site. Surveys have been conducted to track sewage sludge plumes and monitor dispersion and settling characteristics; study plume toxicity and contaminant levels; search for sludge and sludge constituents in surface waters in the area of the Site up 74 km (40 nautical miles) away; maintain a stationary real-time current meter near the Site; deploy and retrieve approximately 50 sediment traps and 17 current meters on 10 arrays from Hudson Canyon south to Delaware Canyon, at depths ranging from 1500 to 2800 m; and deploy satellite-tracked drifters. Results of studies completed to date have provided field data on the chemical and physical behaviour of sludge discharge plumes. Short-term persistence of sludge particles in surface waters above the pycnocline was observed and advection of sludge material from the Site may be rapid, in many cases on the order of hours. A suggestion that removal of sludge material from the surface mixed layer at the Site occurs more from horizontal mixing and advection than from vertical transport processes is supported by the data. Finally, monitoring results have provided data for assessment of permit compliance and for development of additional monitoring to detect far-field transport and long-term impacts - monitoring efforts relative to these concetns continue. 相似文献
256.
The content and distribution of the lead in coal, gangue and the sulfur ball and the pyritic gangue of the Permo-Carboniferous in the North China Plate have been systematically studied (nearly 300 samples) in this paper. The Permo-Carboniferous coals in the North China Plate account for nearly 44.45 of total Chinese coal resources, and most of the steam coals in China come from the Permo-Carboniferous coals in the North China Plate. The result shows that lead content in the coal varied from 1.45 to 63.60 mg kg–1, averaging 23.95 mg kg–1; the lead content of the sulfur ball and the pyritic gangue in the coal seam ranges from 70.26–1060 mg kg–1, with an average of 271.28 mg kg–1; the lead content of the gangue is from 29.5 to 77.81 mg kg–1, averaging at 40.77 mg kg–1. The lead in the coal seam is mainly concentrated in the pyrite, such as sulfur ball, pyritic gangue or pyrite, and is the least concentrated in the organic of coal. The content of the lead has a direct ratio with the ash and the pyretic sulfur. Coal washing can reduce the content of the pyretic sulfur and the lead. 相似文献
257.
Impact of Fencing on the Recovery of the Ground Flora on Heavily Eroded Slopes of a Deciduous Forest
This paper seeks to outline early stages in the recovery of forest ground flora on eroded slopes impacted by recreation activities and to suggest how these data might be applied in the formulation of management policies for forest recreation areas. Based on a fencing experiment in the Sonian Forest near Brussels, we investigated whether, over a 6-year period, the vegetation was able to recover after having been destroyed by recreation use. Short-term trends in overall species composition were already observable during this 6-year study. Species recovery on eroded hills was related to slope, aspect, and soil type. During the considered time scale, the proportion of hemicryptophytes and the number of ancient forest species increased significantly. A downward trend was detected for Ellenbergs nitrogen and temperature indexes and for the proportion of therophytes and pioneer plants of disturbed places. Changes in species frequencies suggest six recovery strategies: early, late, expanding, disappearing, transient, and fluctuating species. Aside from seedling reproduction from overstory influences, Luzula sylvatica appeared to be the most resilient of the species identified in the study since this species has the highest global frequency in our sampling plots and has increased its cover during the study period. Study results indicate that (1) protection from recreation has initiated the recovery of species in the herb layer, but (2) it may take a long time before vegetation previously present in the ground flora may recover in both density and species composition. 相似文献
258.
随着计算机技术的飞速发展,高校计算机教育面临着新的形势。目前在《计算机文化基础》课程教学中存在着学生基础参差不齐、教学模式呆板和考试模式僵硬等问题,提出了相应的改革设想,并在教学实践中初见成效。 相似文献
259.
石油勘探开发是一个庞杂的系统,需要最大程度地获取地下信息。而虚拟现实技术可很好地描述真实的物体,在总结虚拟现实技术研究现状的基础上,阐述了虚拟现实技术在石油勘探开发领域的应用动态。目前,在钻井工程、地震资料解释、海洋石油工程、油田开发工程等方面引入了虚拟现实技术,显示了虚拟现实技术在石油勘探开发中广阔的应用前景。 相似文献
260.
Environmental regulatory agencies' administrative procedures have a significant impact on plant location. The authors review the basic reasons why companies build new plants and the constraints they operate under during site searches. The relationship between these issues and the regulatory agencies' administrative procedures is then shown, as well as the manner in which these procedures influence the site search. On the basis of this discussion, recommendations are made about how state environmental protection agencies can assist site seekers in a manner consistent with their regulatory responsibilities. 相似文献