城市轨道交通地下线引起的环境振动影响因素研究

随着城市的发展,轨道交通在各大城市中得到迅速发展,但与之相伴的环境振动问题也日益突显.为研究城市轨道交通地下线列车运行速度、线路条件、减振措施等运营条件对环境振动影响,在某地铁线路隧道内进行了环境振动源强测试.结果表明,隧道壁源强位置处Z振级随着速度的增加而增大,列车通过速度在57～75 km/h变化时,列车速度每增加...     

风场类型对高层建筑风致响应的影响研究

风荷载是影响高层建筑安全性的重要因素之一,而不同的风环境会对高层建筑的风致响应存在不同程度的影响,基于此背景,本文通过高层建筑多自由度气动弹性模型风洞试验,获得了结构原始加速度时程曲线,采用随机减量法对其气动阻尼进行识别,分析了风场类型对高层建筑气动阻尼比和风致加速度响应的影响。结果表明:横风向气动阻尼比随折减风速的变化起伏较大,顺风向气动阻尼比随折减风速的增大而增大;折减风速小于特定值时,地貌类型对气动阻尼影响较小;随着风场类型从A类变化为D类,结构横、顺风向的气动阻尼比的变化趋势趋于平缓,气动阻尼比的正峰值减小,正峰值风速增大。高层建筑横风向的加速度响应大于顺风向;风场类型从A类变化为D类的过程中,横、顺风向的加速度响应均减小。风向角对气动阻尼比和加速度响应均存在较明显的影响。     

低表面能涂层材料降低海洋生物污损的研究

用浸没法和微量量热法测量了聚四氟乙烯和有机硅氧烷涂层等材料上水的润湿性,计算出涂层表面能色散分量和极性分量,考察这些材料在青岛、厦门海域中的防污性,得出表面能低的色散分量可以延迟藤壶的附着发育过程;有机硅氧烷表面与水高的相互作用力,使表面吸斥盐分,形成淡水液膜,减小了海藻和玻璃海鞘的附着。     

新型的无公害海洋防污涂料

本文概述了海洋防污涂料的发展现状及影响污损生物附着的主要因素,着重论述了低表面自由能材料,吸水性材料的和生化材料等无公害新型防污涂料的防污机制及其试用效果。并指出,开发和应用无锡自抛光涂料和新型低毒防污涂料,这是解决海洋中有机锡污染的近期目标。而刚刚兴起的无公害防污染料尚处在初期研制阶段,其推广应用还需要一个较长时间的发展过程。并且强调应当加强对静,动船舶在苛刻的海洋环境中抗海洋污染生物附着的防污     

A comprehensive review of the energy efficiency on nano coated fin and tube condenser

The condenser is a piece of equipment used to effectively transfer heat from water to the environment. The fin and tube condenser is the most commonly used in commercial applications. The improved performance of heat transfer in the fin and tube condenser is a significant area of study all over the world because optimizing the efficiency of heat transfer in the condenser will contribute to enhancing the effectiveness of system performance. The vapor deposition, plasma spray, and thermal spray techniques are being used, and it is determined that a heat transfer enhancing coating improves condenser performance. This review discusses the nanomaterial coating over the fin and tube condenser in detail. The various nanomaterial coatings with various propositions and coating methods had been discussed with the evidence of previous researchers. At a 50-degree inclination angle on the condensate plate, the condensate over the coating surface increases by more than 30%. The thermal properties of the working fluid are improved over the condenser, and the overall effectiveness of the condenser is increased by approximately 40% over the non-coated condenser. A 1% volumetric concentration of Nanoparticles in the coated material achieves a maximum efficiency increase of 78.7%.     

固相微萃取技术在环境监测分析中的应用进展

样品前处理是整个样品分析过程中的关键一环,其目的在于减少杂质对待测物的干扰及对目标物进行富集。固相微萃取技术是集采样、萃取、富集、进样于一体的样品前处理新技术。近年来,固相微萃取技术在环境污染物监测分析领域得到了广泛应用,该文章系统地综述了固相微萃取技术在不同环境基质(水体、大气、土壤及沉积物)预处理的方法,比较了不同类型涂层材料(如纳米材料、离子液体等)与装置形式(如内部冷却固相微萃取、箭形固相微萃取等)的优缺点及应用范围。针对现阶段固相微萃取技术应用于不同环境基质中存在的问题和不足,提出进一步研究的方向。     

自制固相微萃取涂层用于自来水中五氯酚的测定

采用石英毛细管作为模具,甲基丙烯酸和乙二醇二甲基丙烯酸酯在石英纤维表面原位聚合得到聚(甲基丙烯酸-乙二醇二甲基丙烯酸酯)作为固相微萃取涂层,并以五氯酚为研究对象,采用顶空SPME-GC-ECD法对该涂层的萃取性能进行评价。使用正交试验优化萃取温度、萃取时间、盐浓度、pH和搅拌速度。在最优条件下,建立了水样中五氯酚的分析方法,方法检出限为1ng/L,线性范围为2～5000ng/L,线性相关系数为0.9999,相对标准偏差(RSD,n=5)为8.9%,加标回收率为110.8%。     

Stabilization of potassium permanganate particles with manganese dioxide

A new potassium permanganate reagent with slow-release properties was designed and tested for possible application in in situ chemical oxidation. For this purpose, MnO₂-coated KMnO₄ particles (MCP) were prepared by partial reduction of solid KMnO₄ using the acid-catalyzed reaction with n-propanol or the comproportionation of Mn(VII) and Mn(II) in n-propanol as reaction medium. Column tests showed that, for MCP with a residual KMnO₄ fraction of 70 wt%, the duration of permanganate release under flow-through conditions was prolonged by a factor of 10 compared to untreated KMnO₄. While KMnO₄ is too soluble to be used in reactive barriers, MCP could be introduced into the aquifer by filling of trenches or boreholes; this would allow a prolonged passive dosing of permanganate into the flowing groundwater. In addition, experiments were conducted in order to determine the oxidation capability of native KMnO₄ particles and MCP in CH₂Cl₂, a representative non-polar non-aqueous phase liquid (NAPL). It may be possible to utilize the significantly higher reactivity of MCP under these conditions for the design of slow-release permanganate particles for NAPL source treatment.     

PTFE乳液涂层对针刺毡复合滤料过滤性能的改良

采用PTFE乳液对P84.PTFE混纺针刺毡复合滤料进行涂层整理,并将其与未经整理的试样进行VDI滤料过滤性能模拟测试,进而阐述PTFE乳液涂层对该复合滤料过滤性能的影响。     

南海环境对材料和工艺的影响研究

本文选用装备常用材料及工艺样品在南海西沙进行暴露试验,评价我国当前装备在南海环境条件下的适应能力,并分析南海环境条件对其影响的原因及程度。