新型溴化聚醚PBrMEO的合成及表征

以1,4-丁二醇为起始剂,三氟化硼乙醚络合物为催化剂,3-溴甲基-3-乙基氧杂环丁烷为单体,二氯甲烷为溶剂,按阳离子开环聚合机理,首次合成出新型溴化聚醚(PBrMEO),用IR、1HNMR、GPC、TGA、DSC等测试方法对合成产物进行了表征.结果表明,制备出的PBrMEO均聚物Mn为3000,相对分子质量分布为1.243～1.301,Tg为32.36℃,熔程为118.96～132.84℃,热分解温度为337℃.     

锌钡白煅烧回转窑分段回路控制分析

尽管缺乏传感器和精确模型,合理的工艺流程和控制系统结构以及工人丰富的经验,仍能使回转窑过程由人工操作稳定运行。针对锌钡白煅烧过程,分析煅烧温度和窑炉转．速的历史数据分布。结果表明,人工操作隐含的依据为稳定煅烧温度,从而说明了以此为目标的分段回路控制能有效解决消色力指标无法在线测量的问题。给出了自动控制的效果,并通过对比控制前后信号幅频特性,说明反馈控制对煅烧温度、窑头温度等关键变量的控制效果接近或优于人工操作。     

风管阻尼板的设计与应用

分析了几种阻尼板的阻尼特性,介绍了阻尼板在通风空调系统中的应用,以解决实际工程中各支风管的风量平衡问题,给出了阻尼板调节装置开孔率选用图.     

矿物掺合料与环氧树脂涂层对混凝土抗氯离子侵蚀能力的影响

试验研究了矿物掺合料(不同掺量下单掺粉煤灰、矿渣或硅粉)、环氧树脂表面涂层以及两者共同作用对混凝土抗氯离子侵蚀能力的影响.研究结果表明:矿物掺合料和环氧树脂表面涂层均可显著地提高混凝土的抗氯离子渗透能力;矿物掺合料的改善效果随着掺量的增加而增加,改善能力为硅灰>矿渣>粉煤灰;环氧树脂表面涂层可大幅度降低混凝土的电通量,有效地改善混凝土的抗氯离子渗透性能;矿物掺合料与环氧树脂表面涂层结合使用效果更优.对混凝土抗氯离子渗透性能的机理分析表明:矿物掺合料的火山灰效应、填充效应和对氯离子的初始固化能力是改善混凝土的抗氯离子渗透性能的三个重要因素.     

建筑表皮的拓扑部分

当今随着建筑技术的进步,建筑表皮逐渐朝着跨度更大和覆盖的空间更广的方向转变.在这种趋势影响下,大面积的表皮必须剖分成小面积的单元组合形式.这些剖分形式包括三角形、四边形、六边形、混合剖分以及加细剖分,它们使表皮形态突破了材料尺寸对表皮构成的束缚,同时也使得建筑表皮获得了良好的尺度.更为重要的是这些表皮的剖分形式蕴含着拓扑学的剖分不变性的原理,通过对这些拓扑原理的认识,可以使人们对表皮的构成和设计进行多方位和深层次的把握.     

电涌保护器的应用及其检测

论述了电涌保护器(SPD)劣化与金属性短路和劣化与不确定短路(或开路)两种状态的形成机理。提出了选用SPD时,应首选电压限制型SPD,要求选用的SPD在标准试验条件下不能明显老化,SPD劣化或被破坏时,不会引起着火或电击的危险;SPD劣化与失效时,应采取自身保护脱离器。根据我国的标准,建议在SPD的C级保护中可考虑使用带过电流保护的剩余电流动作断路器(RCBO)作为后备保护元件,并开展监控检测或在线检测工作。     

南宁市GNSS连续运行参考站网络系统建设的体会

GNSS连续运行参考站网络系统（CORS）的建设是一项系统工程,本文着重论述了南宁CORS建设的实施方案及相关技术细节,给出了系统建成后进行集成测试的方法和结论,供同行建站参考。     

Robust and direct evaluation of J2 in linear elastic fracture mechanics with the X‐FEM

The aim of the present paper is to study the accuracy and the robustness of the evaluation of J_k‐integrals in linear elastic fracture mechanics using the extended finite element method (X‐FEM) approach. X‐FEM is a numerical method based on the partition of unity framework that allows the representation of discontinuity surfaces such as cracks, material inclusions or holes without meshing them explicitly. The main focus in this contribution is to compare various approaches for the numerical evaluation of the J₂‐integral. These approaches have been proposed in the context of both classical and enriched finite elements. However, their convergence and the robustness have not yet been studied, which are the goals of this contribution. It is shown that the approaches that were used previously within the enriched finite element context do not converge numerically and that this convergence can be recovered with an improved strategy that is proposed in this paper. Copyright © 2008 John Wiley & Sons, Ltd.     

Fabrication of polymer thin films with in-depth dye-dispersed structures by the vacuum spray method

We report the fabrication of polymer thin films with “in-depth” dye-dispersed structures using a vacuum spray method. Copper (II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine [(t-Bu)₄CuPc] and polycarbonate in chloroform solution were sprayed onto the substrate. The (t-Bu)₄CuPc distribution was controlled precisely during thin film growth by varying its concentration in the solution. Uniform, bilayer, and gradient structures of (t-Bu)₄CuPc dispersed in thin films were confirmed by high-angle annular dark field imaging on scanning transmission electron microscopy. The vacuum spray method has several advantages compared to the casting method, such as smaller dispersed dye-aggregates and lack of cavities due to air bubbles.     

通用型船舶防锈底漆的发展及应用

介绍了改性环氧通用底漆的技术水平和发展现状,分析了改性环氧通用底漆的技术特性和应用前景。