影响粗粒土毛细水上升高度的因素研究

通过对七种粗粒土料进行室内竖管法毛细水上升高度试验,建立了粗粒土毛细水上升高度与时间的关系曲线,并分析了各曲线变化规律和原因。对毛细水上升高度与时间关系试验曲线用各种函数进行了拟合,发现毛细水上升高度与时间过程在对数坐标下用二次多项式回归方程进行拟合效果最好。对方程参数与土料基本物理指标进行逐步回归分析,最终得出粗粒土毛细水上升高度与孔隙率、干容重、d10、d30、d50有着比较密切的联系,在此基础上建立了粗粒土毛细水上升高度的预测公式。     

氯离子侵蚀混凝土有机硅防水处理有效性研究

有机硅表面防水处理能显著提高新建混凝土结构的防水性和防腐性,阻止或延缓混凝土劣化,提高混凝土的耐久性,延长结构的使用寿命。本文通过对氯离子侵蚀程度不同的混凝土进行防水处理,试图分析在沿海环境或其它氯离子污染环境下对既有混凝土结构进行耐久性修复时,有机硅防水处理技术的可行性。结果表明:在氯离子含量为0.515%时,防水处理仍然有效;但当含量达到0.728%时,防水处理已没有意义。     

热传导理论在现代电机绝缘结构设计中的应用

将建筑材料的基础理论应用于电机高导热绝缘材料及高导热电机绝缘结构,论述了导热系数、导温系数、蓄能系数、热阻等因素对电机热场设计的影响。并以电机热场设计实例做对比,提出研究高导热绝缘材料及高导温系统对大型空冷汽轮发电机组热场设计的重要性。     

巨型框架结构体系超高层钢结构设计与施工技术

北京电视中心工程首次在工程中对巨型钢框架结构体系进行了研究与应用的工程,针对巨型框架结构体系超高层纯钢结构设计与施工方面的特点和难点,主要研究应用了巨型框架平面控制轴网竖向传递精度控制技术、巨型钢框架结构上下巨型钢桁架协同受力施工技术、悬空大跨度空间钢管桁架安装技术、大型液压爬架安全防护技术、巨型桁架高精度整体提升技术和斜铁楔紧固定法内爬式塔式起重机群塔作业施工技术,是北京市目前最高的纯钢结构建筑。     

Rapid,Controllable Fabrication of Regular Complex Microarchitectures by Capillary Assembly of Micropillars and Their Application in Selectively Trapping/Releasing Microparticles

A simple strategy to realize new controllable 3D microstructures and a novel method to reversibly trapping and releasing microparticles are reported. This technique controls the height, shape, width, and arrangement of pillar arrays and realizes a series of special microstructures from 2‐pillar‐cell to 12 cell arrays, S‐shape, chain‐shape and triangle 3‐cell arrays by a combined top down/bottom up method: laser interference lithography and capillary force‐induced assembly. Due to the inherent features of this method, the whole time is less than 3 min and the fabricated area determined by the size of the laser beam can reach as much as 1 cm², which shows this method is very simple, rapid, and high‐throughput. It is further demonstrated that the ‘mechanical hand’‐like 4‐cell arrays could be used to selectively trap/release microparticles with different sizes, e.g., 1.5, 2, or 3.5 μm, which are controlled by the period of the microstructures from 2.5 to 4 μm, and 6 μm. Finally, the ‘mechanical hand’‐like 4‐cell arrays are integrated into 100 μm‐width microfluidic channels prepared by ultraviolet photolithography, which shows that this technique is compatible with conventional microfabrication methods for on‐chip applications.     

TiO_2/ZnO纳米管的制备及其光催化性能

采用电化学阳极氧化法制备了高度有序的TiO2纳米管阵列,并利用纳米管的光致超亲水特性,采用斜面毛细组装技术在无定形TiO2表面自组装ZnO溶胶后退火制备了TiO2/ZnO复合纳米管.探讨了阳极氧化各参数对纳米管形貌的影响.利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)等方法对样品的结构和形貌进行了表征.以有机磷农药氯胺磷为光催化降解对象,研究了焙烧温度、管径、管长和TiO2/ZnO复合比例等因素对降解效果的影响.结果表明,焙烧温度、管径以及ZnO复合比例对光催化降解率影响较大.对于管径97 nm、管长315.8nm的TiO2/ZnO纳米管,ZnO最佳复合比例为4.2%(质量分数),5 h后降解率达到78%.     

毛细管平面辐射空调系统免费冷源的研究

在阐述闭式冷却塔供冷的工作原理及毛细管空调系统特点的基础上,比较分析了不同闭式冷却塔供冷模式,确定了夏季以闭式冷却塔直接为毛细管平面空调系统提供冷源是一种节能的有效模式。随后,根据标准年气象资料,对乌鲁木齐地区室外空气湿球温度进行了分析,结果表明,该地区全年有8376h湿球温度不超过16℃,可以利用冷却塔循环冷却水直接供冷,且夏季三个月当中有1930h可以实现免费供冷,这对在我国西部地区推广毛细管平面辐射空调系统具有积极意义。     

Interfacial Capillary‐Force‐Driven Self‐Assembly of Monolayer Colloidal Crystals for Supersensitive Plasmonic Sensors

Colloidal lithography technology based on monolayer colloidal crystals (MCCs) is considered as an outstanding candidate for fabricating large‐area patterned functional nanostructures and devices. Although many efforts have been devoted to achieve various novel applicatons, the quality of MCCs, a key factor for the controllability and reproducibility of the patterned nanostructures, is often overlooked. In this work, an interfacial capillary‐force‐driven self‐assembly strategy (ICFDS) is designed to realize a high‐quality and highly‐ordered hexagonal monolayer MCCs array by resorting the capillary effect of the interfacial water film at substrate surface as well as controlling the zeta potential of the polystyrene particles. Compared with the conventional self‐assembly method, this approach can realize the reself‐assembly process on the substrate surface with few colloidal aggregates, vacancy, and crystal boundary defects. Furthermore, various typical large‐scale nanostructure arrays are achieved by combining reactive ion etching, metal‐assisted chemical etching, and so forth. Specifically, benefiting from the as‐fabricated high‐quality 2D hexagonal colloidal crystals, the surface plasmon resonance (SPR) sensors achieve an excellent refractive index sensitivity value of 3497 nm RIU^?1, which is competent for detecting bovine serum albumin with an ultralow concentration of 10^?8 m . This work opens a window to prepare high‐quality MCCs for more potential applications.     

小型制冷装置毛细管可视化实验研究

设计并搭建了一套小型制冷装置毛细管可视化实验台以及计算机图像采集系统,改变实验工况,得到了透明毛细管管长方向上不同距离处的管内流动状态图,通过开发的图像处理程序对其进行处理,获得流动状态处理图,并以此分析了小型制冷装置毛细管内的两相流特性.     

HDPE在高压毛细管挤出过程中的温度窗口效应

对三种不同类型高密度聚乙烯(HDPE)进行高压毛细管挤出,均发现特殊的温度窗口效应,线性均聚5000S在v=8mm/min时的温度窗口为145℃~150℃;己烯共聚HXM TR-571在v=1mm/min时的窗口为150℃~153℃;双峰型GC100S在v=5mm/min的窗口为143℃~145℃,温度窗口内挤出压力骤降至最小值,挤出平稳,挤出物表面光滑,避免了压力振荡和变形,窗口与PE的分子量、支化度和柱塞速率有关。效应产生的原因是在温度窗口内发生了PE晶形相转变。不同挤出温度挤出物的差示扫描量热(DSC)分析表明,HXM TR-571和GC100S在窗口温度下挤出物具有较高的结晶温度(Tc)和较低熔点(T(m 2))。