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排序方式: 共有408条查询结果,搜索用时 156 毫秒
271.
荆门市城区降尘调查分析及对策 总被引:2,自引:0,他引:2
采用网格布点法对荆门市城区降尘进行普查性监测,采用类比法进行数据分析。结果表明,对荆门市降尘平均水平起主要作用的是地表扬尘,它取决于两个相互作用的因素,地表积尘量(与降雨、城区绿化地面硬化水平及城区环境卫生有关);地表扰动(风力、车流量等自然及人为活动因素)。春季,沙尘天气是荆门城区降尘的重要来源。工业污染源对个别区域影响巨大。根据调查分析提出有效防治对策。 相似文献
272.
高分子环保固沙剂的研究 总被引:2,自引:0,他引:2
介绍了一种以聚乙烯醇(PVA)为主要基料的乳状液高分子环保固沙剂,该高分子环保固沙剂无毒、无副作用、价格低廉、性能优异、不污染环境、原料易购、使用方便.针对沙土为研究对象,主要作了固结层的透水性,抗老化性,抗风蚀的室内固沙实验方面的初步探讨. 相似文献
273.
274.
天然锰砂去除工业冷却水中的锰、铁污染 总被引:2,自引:0,他引:2
采用天然锰砂滤料接触氧化法对去除工业冷却水中锰、铁的工艺条件进行了研究。滤料粒径05mm~10mm,滤床高800mm,滤速10m/h~12m/h,工作周期96h,反冲洗强度13L/m2·s,反冲洗时间5min~7min。出水Mn2+浓度达004mg/L以下。锰去除率80%以上,总铁浓度可达检验不出的水平。 相似文献
275.
北京及其周边地区分布的大量裸露沙荒地是北京近年来沙尘暴频发的主要沙源之一,而增加其地表覆盖状况则是遏止就地扬沙起尘的有效措施之一。以北京西北部河北宣化黄羊滩为例,对流动沙丘上铺设生态垫并栽植灌木的防风固沙效果进行了初步研究。研究结果表明,与沙柳沙障相比,生态垫确实可以降低近地表的输沙率,提高生态垫下土壤的养分含量,一定程度上提高柠条的地径和高度,可见生态垫是一种很好的促进流沙固定和植被恢复的地表覆盖材料;与其它两种生态垫铺设方式(品字状和带状)相比,全铺可以显著降低近地表的输沙率,提高其下土壤的养分含量,但柠条的生长状况却略差,这可能与全铺降低了小雨入渗的可能性有关;就两种部分铺设的方式而言,无论从降低近地表的输沙率还是促进柠条的生长上来看,品字状都明显优于带状。从生态和经济的角度综合考虑,品字状铺设显然是该区域流沙防治措施中较好的选择。 相似文献
276.
277.
Detection of Asian dust aerosols using meteorological satellite data and suspended particulate matter concentrations 总被引:1,自引:0,他引:1
Naoko Iino Kisei Kinoshita Andrew C. Tupper Toshiaki Yano 《Atmospheric environment (Oxford, England : 1994)》2004,38(40):6999-7008
The advection and dispersion of Asian dust events from China to the Pacific Ocean around Japan during 2000–2002 were investigated using the meteorological satellite data of NOAA/AVHRR and GMS-5/VISSR. Aerosol vapour index images, taking the brightness temperature difference between 11 and 12 μm, are very effective for monitoring the Asian dust phenomenon in the East Asia region, with their capacity for detection during the day or night. We discuss the dust events, focusing on the advection patterns shown in satellite images, which are classified into three types as ‘dry slot’, ‘high-pressure wedge’ and ‘travelling high’, based on synoptic patterns. The results are compared with suspended particulate matter concentrations measured at Japanese surface stations and with ground-based observations of Sakurajima volcano by a web camera system at Kagoshima in Kyushu, Japan. We found that the passage of cold fronts caused a rapid increase of suspended particulate matter (SPM) concentrations, which exceeded 100 μg m−3, and that deep low-pressure complexes strengthened the dust phenomenon. The ‘high-pressure wedge’ type is seen much more clearly in satellite images than the ‘travelling high’ type, but SPM concentrations and visibility were similar in both owing to the differences in the vertical distribution of the dust and in viewing conditions. 相似文献
278.
279.
Fluidized bed and induced crystallization technology were combined to design a new type of induced crystallization fluidized bed reactor. The added particulate matter served as crystal nucleus to induce crystallization so that the insoluble material, which was in a saturated state, could precipitate on its surface. In this study, by filling the fluidized bed with quartz sand and by adjusting water p H, precipitation of calcium carbonate was induced on the surface of quartz sand, and the removal of water hardness was achieved.With a reactor influent flow of 60 L/hr, a fixed-bed height of 0.5 m, pH value of 9.5, quartz sand nuclear diameter of 0.2–0.4 mm, and a reflux ratio of 60%, the effluent concentration of calcium hardness was reduced to 60 mg/L and 86.6% removal efficiency was achieved. The resulting effluent reached the quality standard set for circulating cooling water. Majority of the material on the surface of quartz sand was calculated to be calcium carbonate based on energy spectrum analysis and moisture content was around 15.994%. With the low moisture content, dewatering treatment is no longer required and this results to cost savings on total water treatment process. 相似文献
280.
Climatology,Trend Analysis and Prediction of Sandstorms and their Associated Dustfall in China 总被引:2,自引:0,他引:2
Sun Leng Zhou Xukai Lu Juntian Kim Yong-Pyo Chung Yong-Seung 《Water, Air, & Soil Pollution: Focus》2003,3(2):41-50
Based on statistical data about Sand and Dust Storms (SDS) and their associated dustfall, features of temporal and spatialdistribution were studied first in this article. SDS and associateddustfalls occurred most often in northern China, especiallynorthwestern China. However, in the last two years, they have atendency to occur on the central and western parts of the Inner Mongolia Autonomous Region. As a result, Beijing is now among the impact areas, and the Chinese government is paying greaterattention to the matter. The changing trends of SDS and associated dustfalls were subsequently analyzed. Occurrences were seen to be decreasing with the feature of fluctuation duringthe period of 1954–2001, but they have slightly increased since 2000. Also, climate factors related to SDS and associated dustfalls were discussed. Finally, it was recommended that methods to predict SDS in China be further studied in the future. 相似文献