Adhesion Mechanisms of Polyurethanes to Glass Surfaces I. Structure-Property Relationships in Polyurethanes and Their Effects on Adhesion to Glass

Polyurethanes were prepared from toluene diisocyanate (TDI), 1-4-butane diol (BDO) and polycaprolactone-based triols with varying molecular weights. Among each molecular weight triol-based urethane, hard segment content was varied from 20% to 70%. Differential scanning calorimetry, tensile testing, and Iosipescu shear testing were done on all the various urethanes prepared. Thermal characterization data revealed the dependence of phase separation on hard segment content as well as on the triol molecular weight. Tensile data and Iosipescu shear data further confirmed the observations made from the DSC data. The data further indicated that phase separation can greatly improve the modulus of cross-linked segmented urethanes. Adhesion of these urethanes to glass surface was evaluated using soda-lime float glass plate. Urethane samples were cast on the air side of the glass plates and adhesion was measured in shear mode. Adhesion data indicated that in addition to hard segment content, modulus, cross-link density, and molecular weight of the triols, phase separation seems to be a major factor in controlling adhesion. Surfaces of the failed adhesion samples were also analyzed and the failure mode was found to be cohesive, in varying degree, with the different urethane systems.     

单螺杆挤出过程的数值模拟

以三段七区物理模型为基础，采用面向对象程序设计语言VisualC ，对整个单螺杆挤出过程进行了数值模拟。所得压力。温度等工艺参数的模拟结果与实验值吻合较好，说明采用数学模型的正确性和数值算法的可行性。     

Characterisation of mortar morphology in thin sections by digital image processing

A digital imaging approach was applied to investigate mortar morphology in thin sections; in particular, the binder/aggregate ratio and the grading curve of five mortar bars were attained by digital image processing (DIP), using the Image Pro Plus 4.1 software package. The imaging procedure employed image segmentation, to extract mortar aggregate, and image filtering, to fix grain boundaries. The results show that digital image processing may be considered as an alternative method to mechanical sieving for the characterisation of mortar morphology, as it appears to be quicker and more accurate than the traditional method. However, digital image processing exhibits limits, which are discussed in the text.     

基于两阶段人工鱼群算法的U型渠道断面优化设计

渠道断面优化是控制农田水利工程成本的重要因素,已有的渠道断面优化研究以梯形渠道为主,对U型渠道研究较少。以优化U型渠道深度、圆弧半径和直线段外倾角为目标,建立以U型渠道过水断面面积最小为目标函数、满足设计流量要求的数学优化模型。根据U型渠道水力计算的复杂性,利用引入协调行为的两阶段人工鱼群算法,对渠道断面设计进行优化。优化结果满足边坡稳定等约束条件。将模型应用于连云港市赣榆区黑林镇土地整理项目,10条斗渠过水断面面积均减小,优化后占地面积共减少28.603 m~2,占原占地面积的5.0%。     

Bubble Formation at a Rotating Cylindrical Surface in Cross‐Flowing Liquid

A novel method of gas sparging from a rotating cylinder is proposed, which prevents against formation of large attached gas cavities in cross‐flowing liquids including those flowing downwards. Experimental and theoretical results regarding critical rotation speed necessary to remove the attached cavity, bubble formation process and size distribution of the produced bubbles in a low viscosity system (air‐water) are presented in this study.     

异形管内水力、传热性能的数值模拟

通过数值计算考察了横纹管、缩放管两种异形管内的流动与传热性能。计算时采用标准k-ε湍流模型：采用控制容积法对控制方程进行离散化；采用SIMPLE算法进行压力修正：代数方程采用超松弛法迭代求解。很出了在充分发展流时的传热努塞尔数、速度、瘴撩系数及湍动能分布，并与光滑管内的流动传热进行了比较，分析了异形管在强化传热方面的机理。计算结果和实验值比较吻合。     

引汉济渭椒溪河隧洞施工通风数值模拟研究

引汉济渭工程是陕西省为缓解关中渭河沿线城市和工业缺水问题,而提出的由汉江调水到渭河流域的大型水利工程。椒溪河段工程为穿河段,地形地质相对复杂,隧洞施工期的通风问题也相对比较严重。采用CFD(Computational Fluid Dynamics)数值模拟方法对带有支洞隧洞的通风过程进行模拟,研究几种典型工况下隧洞内的流场和浓度场在施工期时随时间的变化规律,分析掌子面以及支洞内涡流对气流及有害气体分布的影响。在气流排散通道不顺畅时,掌子面附近的涡流区域内涡流的大小和位置呈现周期性的变化,并随通风时间的增加影响范围逐渐降低。隧道爆破产生的有害气体和烟尘会随着气流的流动发生移动和扩散过程,并逐渐排向洞外。通过对隧洞主洞与支洞内气流和有害气体排散过程的研究,得出隧洞爆破后在通风作用下隧洞的掌子面附近和支洞与主洞的交叉位置处形成涡流区,涡流的产生和变化不断的消耗通风的机械能,降低通风效率,对有害气体的排散造成一定的阻滞作用,隧洞内有害气体的排散过程包括移动和扩散两方面,移动过程将CO排向洞外,扩散过程不断的降低洞内CO峰值,总结出了不同工况下隧洞内达到安全浓度的时间,对隧洞施工进度给出一定的参考意见。     

观音岩水电站厂房坝段接缝灌浆工艺

观音岩水电站装机容量 3 000 M W, 为一等大( ? ) 型工程。厂房坝段设置 5条横缝, 分为 6 个坝段。通过接缝 灌浆, 极大的改善厂房坝段受力条件, 提高大坝结构整体性和耐久性。结合观音岩水电站现场施工条件, 从施工角 度论述了接缝灌浆的施工工艺以及施工过程中可能存在的问题及处理方法。     

燕化660 kt/a乙烯冷区设备布置

主要介绍了大型乙烯改扩建的冷区设备布置的主要特点，分析了设备布置的思路，及与土建等各专业的关系，强调了设备布置方案利旧的方法。     

基于Eclipse的嵌入式集成开发环境的研究与实现

为简化嵌入式开发的流程,提高程序开发效率,通过对各类平台上通用的开发环境的研究和分析,基于MIPS架构、龙芯3A目标机上嵌入式操作系统和集成开发环境的研发项目,在x86宿主机上设计并实现龙芯3A平台的交叉编译开发环境.将开发过程中需要使用的编译、调试等功能以插件形式嵌入开发环境中,提出改进编译和工程管理的方法并予以实现,使得应用程序能够在目标机上运行和调试,提高了开发效率.