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地铁运行引起的地面振动实测及传播规律分析 总被引:6,自引:0,他引:6
对地铁线路某区间段的地面振动进行实测,采集不同测线和不同测点处的水平方向、竖直方向加速度,并转化为傅里叶幅值谱对其进行衰减规律分析。利用公式将加速度记录换算为振级和分频振级,参照相关的国家标准分析不同距离处的振级和频率成分。对比同一加速度记录中的两对开方向列车引起的地面振动,进一步分析振动衰减的规律。所得到的结果可供地面建筑的隔振减振及城市轨道的规划和设计参考。 相似文献
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微波法复合絮凝剂PAFC-PAM的制备及脱色性能 总被引:3,自引:0,他引:3
研究了以三氯化铝,三氯化铁和阳离子聚丙烯酰胺为原料,在微波辐照下制备PAFC-PAM复合絮凝剂的工艺条件,探讨了pH值、复合絮凝剂投加量对活性染料模拟废水脱色率的影响,并考察了其对实际印染废水的处理效果。结果表明:在PAM/PAFC质量比为0.25、微波合成功率150W、微波时间3min制得的复合絮凝剂,浊度去除率为98.8%。在pH=8,投加量为42mg/L的最佳絮凝条件下,复合絮凝剂对模拟染料废水脱色率高达97%。与PAFC和PAM相比,PAFC-PAM具有较宽的pH适宜范围和较低的投加量且对实际印染废水的处理效果优于PAFC和PAM。 相似文献
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Tosh JE Senior E Smith JE Watson-Craik IA 《Environmental pollution (Barking, Essex : 1987)》1994,83(3):335-340
Vertically migrating landfill gases pose inimical challenges to site revegetation strategies. Laboratory studies were made to examine the efficacy of ectomycorrhizae and soil cover to obviate the challenges of ethylene and methane. In the presence of ethylene concentrations = 640 ppm the mean colony radial extension rates of the fungal isolates Laccaria proxima, Paxillus involutus and Hebeloma crustuliniforme were comparable with the non-ethylene controls. H. crustuliniforme afforded no protection to Betula pendula (Silver Birch) seedlings. Methane removal by the soil cover may be important to minimise the indirect phytotoxic effects of methane on tree seedlings. In closed culture enrichments with refuse as inoculum source material methanogenesis consistently exceeded methanotrophy even after major oxygen perturbations. With subsoil and topsoil, however, net methane concentrations decreased, thus emphasising the importance of these cover materials in site restoration strategies. 相似文献
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