低表面能船舶防污涂料的疏水结构及防污性能

以有机硅改性丙烯酸树脂为基料,添加纳米SiO2和超细颜填料粉体,制备了低表面能船舶防污涂料.用接触角检测仪测量涂膜表面的接触角,用数码显微镜观察水与涂膜之间的界面,用扫描电镜对涂膜表面形貌进行分析,并在大连湾进行实海挂板试验.结果表明,水滴与防污涂料涂膜的接触角可达149°,接触界面间存在着大量气垫,涂膜表面具有微米-纳米阶层结构,这是涂膜疏水及防止污损生物附着的主要原因.     

憎水性材料用于路面除冰效果研究

在总结国内外沥青路面除冰对策的基础上,对憎水性材料用于沥青路面除冰的原理进行分析,并结合相关室内试验验证憎水材料的除冰效果,检测沥青路面涂有憎水材料后的抗滑性,对于指导实际工作有一定的意义.     

疏水化合孔栓物对高性能混凝土性能影响的试验及应用

研究疏水化合孔栓物对不同强度等级的高性能混凝土工作性、力学性能及耐久性的影响。结果表明:疏水化合孔栓物可改善新拌混凝土工作性、显著降低混凝土吸水率,混凝土吸水率普遍降低50%以上,同时可提高混凝土抗氯离子渗透性。疏水化合孔栓物降低混凝土早期强度,但对后期强度无明显影响。该内掺型疏水材料在范和港跨海大桥、东华大桥等工程中得到推广应用,显著提高了混凝土结构耐久性。     

疏水微形貌表面水下减阻研究进展

疏水微形貌表面减阻是一种新型仿生减阻方法,也是国内外减阻研究领域的热点之一。该文在分析天然及人造疏水微形貌表面界面一般特性的基础上,从壁面滑移流动、表面微形貌等角度总结了国内外疏水微形貌表面减阻理论研究的最新成果,然后分类给出了近年来疏水微形貌表面减阻微观及宏观试验的研究进展,最后分析了疏水微形貌表面可能的减阻机理及目前存在的技术问题。     

疏水装置放水管温度场的数值模拟

水蒸汽管道中的冷凝水由疏水装置排出。为研究极寒地区疏水装置放水管冬季结冰的问题,采用计算流体力学软件Fluent建立了放水管死管段热损失的物理模型,并对管道内部温度场进行模拟分析。模拟结果很好地显示了管道内的温度场,并得到了管道轴线上的温度分布,结果表明:死管段长度对管道内温度场有重要影响。将死管段长度控制在0.2 m以内,可有效避免放水管冷凝水结冰的问题。     

橡胶颗粒对水泥净浆水化产物影响的XRD分析

采用X射线衍射试验(XRD)研究了掺加橡胶颗粒的水泥净浆水化产物的物相结构.结果表明:(1)水泥净浆的抗压强度随橡胶颗粒掺量的增加而降低;(2)尽管水泥的化学成分复杂,但掺入橡胶颗粒后,在其水化产物中并没有发现新的物相结构;(3)掺加橡胶颗粒的水泥净浆的水化产物中氢氧化钙(CH)晶体的衍射峰强度显著降低,原因之一可能是...     

岩溶隧道衬砌施工缝疏水涂层长期工作性能研究

岩溶隧道排水系统中普遍存在岩溶水碳酸钙结晶堵塞反复出现的问题,从而引发隧道渗漏水加剧,危及隧道运营安全.在依托工程中,对岩溶地区运营公路隧道衬砌施工缝渗漏水进行了引排水处理,并在排水半管的混凝土基面上施作了疏水涂层以减少结晶的附着,针对该疏水涂层的长期工作性能进行了室内试验和现场监测.选取基面接触角作为表征指标,通过室...     

Dissolved organic matter studies in enclosed systems: Application of Hydrophobic fractionation for the assessment of organic nitrogen dynamics

The evolution of dissolved organic matter (DOM) in a non-axenic batch culture of the marine diatom Thalassiosira tumida was studied by hydrophobic fractionation during a three month experiment. DOM was fractionated with XAD-2 resin into hydrophobic (acid and neutral, “humic”) and hydrophilic fractions. The combined amino acid contents of unfractionated filtered seawater, XAD-fractions and particulate material were determined during the growth, stationary and degradation phases of the culture, and variations related to changes in dissolved organic nitrogen (DON) in XAD-fractions, dissolved inorganic nitrogen, algal and bacterial biomass. XAD-fractionation enabled the discrimination of simultaneously ocurring release and uptake of organic nitrogenous compounds: During the diatom growth there was a net increase of tolal DON concentrations, which was mostly accounted for by the hydrophilic fraction. A concurrent heterotrophic uptake of combined amino acids and other non-amino acid organic nitrogen was discernible by the decrease of their concentrations in the hydrophobic fractions. In the stationary phase, during the prevailing net consumption of total DON, the production of algal exudates could be detected in the hydrophobic fractions, while uptake mainly involved non-amino acid organic nitrogen from the hydrophilic fraction. During the degradation phase, after two months part of the particulate amino acid pool was transformed into hydrophilic DON, which in contrast to the stationary phase, was not adequate for supporting sustained bacterial growth. This suggests that the generation of recalcitrant substances may begin in the hydrophilic fraction of DOM. A slight increase of the hydrophobic acid fraction was indicative of the incipient formation of humic substances. XAD-2 was able to adsorb substances from fast changing DOM pools and thus should be a useful tool in studies concerned with phytoplankton and bacterial dynamics.     

纳米SiO_2制备无毒疏水海洋防污涂料

以有机硅改性丙烯酸树脂作为成膜物质,通过在常规颜填料中添加疏水型纳米二氧化硅,对涂料的表面结构进行改性,制备出具有微米-纳米阶层结构的无毒疏水海洋防污涂料.讨论了颜填料加入量对涂膜附着力的影响、纳米S iO2加入量对水滴与涂膜表面接触角的影响.结果表明:颜填料的质量分数为31%时,涂膜附着力为1级;纳米二氧化硅的加入量占颜填料总质量为35%时,水滴与涂膜表面接触角为126.°     

疏水表面流体流动特性的格子Boltzmann方法模拟

采用格子Boltzmann方法研究了微形貌对固体表面润湿性的影响,在此基础上进一步模拟了具有微形貌的疏水表面通道内的流体流动,从法向速度、剪应力、滑移速度等角度分析了疏水表面的流场特性,揭示了疏水表面滑移流动的产生机制。结果表明,疏水表面的滑移流动是由低表面能作用和微形貌共同引起的。具有微形貌的疏水表面比光滑疏水表面具有更好的减阻效果,原因在于微形貌能够驻留气体,形成的气液自由剪切面加剧了疏水表面的滑移流动,最大滑移速度可以达到主流平均速度的50%左右。