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为了拓宽我国脱硫石膏的利用途径,实现对脱硫石膏直接利用,本研究选取谷氨酸钠作为缓凝剂,聚羧酸作为减水剂,对脱硫石膏现浇墙体材料进行改性研究。试验结果表明:电厂的脱硫石膏经过55℃预烘干2 h,160℃烘干3 h,按照GB/T 17669.4-1999确定标稠需水量,添加3%谷氨酸钠作为缓凝剂,0.5%聚羧酸作为减水剂时,现浇墙体材料的初凝时间约54 min,终凝时间延长至96 min,复配后初终凝时间满足施工要求;墙体材料的绝干抗折强度为3.31 MPa,绝干抗压强度为12.27 MPa。 相似文献
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为了降低建筑垃圾肆意堆放造成的围城风险,提高建筑垃圾高值资源化利用程度,增强再生材料工程安全性能,采用控制变量法,开展了建筑垃圾再生骨料杂质种类及含量对再生混凝土性能的影响研究。结果表明,在设计配合比条件下,建筑垃圾再生混凝土28d抗压强度满足C25强度等级要求,且具有较高的安全余量,表现出韧性强,抗变形性能好等力学特征。混凝土性能主要受再生骨料杂质含量、吸水性、粘合性、填充性等因素影响。其中,木屑和金属可显著提高混凝土浆体的粘聚性,降低流动性,最大降幅接近50%。而玻璃提高了混凝土拌料的流动度,最大增幅达32%。当玻璃掺入量达到6%时,混凝土28d抗压强度约18MPa,降幅接近50%,严重制约混凝土安全性。因此,建筑垃圾资源化利用时,应提高骨料除杂分选效率,降低再生骨料的含杂率,其杂质总含量宜低于3%,以保障再生混凝土的安全性及工作性。 相似文献
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湿热试验是模拟客观自然环境条件对电子产品进行的考验。根据整机电子产品的安全标准GB8898-88的规定:整机在湿热试验结束后立即进行抗电强度的检验。本文扼要地分析整机电子产品在湿热试验后抗电强度的重要性,并重点讨论电子产品在湿热后抗电强度检验中存在的问题及主因,以达到提高产品安全性的目的。 相似文献
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《中国环境管理干部学院学报》2016,(6)
基于山东省17个城市的土地经济密度数据,利用变差系数、相对发展率分析等方法,初步探讨了2005—2014年山东省城市土地经济密度的动态演化格局及区域差异特征。研究结果表明:山东省各城市土地经济密度均呈现上升趋势;土地经济密度原本较高的城市,其土地经济密度相对发展速度也较快,各城市相对发展速度呈现不同;济南和青岛的增长极效应显著,带动周边城市经济效益提升;城市土地经济密度的主要影响因素包括自然因素、经济因素和政策因素,具体包括城市区位、城市交通状况、城市产业结构和城市土地投入等方面。 相似文献
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Trametes versicolor decolorized 2000 mg L(-1) of the mono-azo substituted naphthalenic dye Amaranth with no dye sorption observed visually. The changes in the toxicity were assessed over a period of 30 d for the dye-treated viable culture, control (no dye added), and a boiled culture treated with dye, using the Microtox Acute Toxicity assay. Before dye addition, the culture filtrate had some toxicity, which increased after the dye addition. The toxicity of the dye-treated culture decreased during the treatment. The loss of toxicity occurred at the same time, with the loss of color suggesting that detoxification is associated with decoloration. The change in pH was due to natural metabolic processes and had a small effect on detoxification. Because the toxicity of the treatment was similar to that of the control at the end of the treatment, the effluent seems to be safe for release into the environment, potentially rendering this treatment suitable for industrial application. 相似文献
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泵站树状给水管网流量具有随机性,而这种随机性变化会直接影响管网的建设费用和动力费用.针对这-特点,应用随机规划原理,建立泵站树状给水管网机会约束模型,编写基于随机模拟的遗传算法程序求解该模型.机会约束模型能较客观地反映该管网的实际工况,使优化设计结果更符合实际. 相似文献
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城镇化是推动我国经济社会发展的重要动力,在高速发展的同时,带来大量污染排放,威胁乡村环境质量与可持续发展。在对乡村生态环境问题剖析的基础上,从战略、实施、方式等层面探索解决思路,围绕科学规划、发展方式、基础建设、管理机制、宣传教育等方面分析关键点,加强乡村环境保护,保障城镇化建设健康发展,为促进农村农业持续发展提供持久动力。 相似文献
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阐释了信息产业专门化街区的内涵,结合对合肥市黄山路信息产业专门化街区构成要素的分类及其邻近度的分析,分别从空间结构演化、景观演化、功能演化三方面阐述了合肥市黄山路由"电子一条街"向"信息产业专门化街区"的总体演化阶段,探讨了信息产业专门化街区的未来发展趋势。 相似文献
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Günay Kocasoy 《Environmental management》1989,13(4):469-475
The increase in the number of tourists visiting a coast is desired by most of the countries for economic reasons. However, this increase in tourism may cause pollution of the sea. This can be only avoided by proper planning and by predicting the carrying capacity of the coast in terms of sea pollution. This is especially important for developing countries where part of the wastewater is discharged without any treatment into the sea.In the present study the beaches were classified according to their use — and consequently the amount of waste discharged into the sea — into four groups: (1) coasts that are used only for swimming and recreational purposes; (2) coasts used simultaneously for dwelling, swimming, and recreational purposes; (3) coasts along which only dwellings exist; and (4) natural and man-made harbors, i.e., coasts used as shelters. During the survey,40,320 observations were made between December 1985 and February 1988 to determine the effect of the number of tourists on seawater quality. The results obtained were analyzed by a multilinear regression program to obtain an empirical equation giving the extent of the sea pollution in terms of coliform concentration as a function of population density and some other environmental factors.The equations derived in this study enable the determination of the carrying capacity of a beach in terms of pollution as well as the expected degree of pollution corresponding to a given population density. Furthermore, it allows the prediction of the extra carrying capacity that can be obtained by improving the waste-disposal conditions. 相似文献
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燃煤二氧化硫控制技术应用概况 总被引:1,自引:0,他引:1
由燃煤引起的二氧化硫污染已成为大气环境中最主要的污染因子。为解决这个问题,我国结合国外的技术成果,进行了各种脱硫技术的研究。介绍了各种治理技术应用情况,并结合实际经验对其中应注意的问题给予评述。 相似文献