Drying Shrinkage of Cement-Based Materials Under Conditions of Constant Temperature and Varying Humidity

Currently, deformations along the central axis of specimens were usually measured under fixed environmental conditions. Seldom were the effects of environmental factors on the drying-shrinkage deformation of cement-based material considered. For this paper, the drying-shrinkage deformation at different w/b ratios and different additions to mortars was investigated under different environments at a temperature of 20℃ and humidity ranging from 100% to 50%. The specimens were cured in water for 28 days before measurement. The results illustrate that mortar shows much less shrinkage under various drying conditions when a lower w/b ratio is adopted. With a decrease in relative humidity the speed of drying-shrinkage becomes gradually lower. The addition of silica fume reduces the drying-shrinkage of mortar under higher relative humidity, because the pore structure of mortar with silica fume becomes more refined. The addition of fly ash increases the total porosity and the volume of coarse pores in the mortar. The drying-shrinkage of mortar under different conditions increases with the addition of more of fly ash.     

浅析CVT电容分压器在10kV下的介质损耗角正切

主要分析了CVT电容分压器在10kV和Un下的损耗角正切(tanδ)之间的关系,影响电容分压器10kV下的tanδ的因素,其中着重分析tanδ与真空干燥处理工艺之间的关系。并提出了降低tanδ的若干技术措施。     

中短波广播发射台的安全监控系统

本文介绍了中、短波广播发射台的视频及红外监控系统的设计背景、原则、功能和特点,提出了具体的解决方案,详细阐述了该方案的组成系统.     

三种提高褐煤锅炉中速磨煤机干燥出力方法的对比分析

介绍了三种提高褐煤锅炉中速磨煤机制粉系统干燥出力的方法,分析了其系统特征、运行情况及存在的问题,并对优缺点进行对比。结果表明:热一次风蒸汽加热系统布置简单、工程实施难度小、锅炉效率高、成本低、干燥出力提升效果明显。     

无溶剂漆在矿用电机修理中的浸漆实践

就矿用电机修理中,有溶剂漆和无溶剂漆的浸漆质量、材料消耗、作业人员的劳动条件和作业环境,用理论和实践的方法进行了分析比较,进一步验证了无溶剂漆比有溶剂漆浸漆具有优越性,并给出了无溶剂漆在浸漆中出现的问题的解决办法。     

闪蒸干燥技术在白炭黑生产中的应用

通过采用闪蒸干燥技术，对原白炭黑生产中的干燥设备进行了改造，对改造前后的效果进行比较，阐述了闪蒸干燥技术的特点。     

基于风扇磨仓储式制粉系统的褐煤烟气预干燥发电系统分析及优化研究

基于风扇磨仓储式制粉系统的褐煤烟气预干燥发电系统建立了全厂分析模型,从热力学第二定律角度探究该系统的节能原理.以某600 MW超临界机组为例,对各级子系统及主要设备展开分析.结果表明:褐煤烟气预干燥发电系统的全厂效率相对常规褐煤发电系统可提高3.42%;采用仓储式制粉系统将干燥乏气与煤粉分离,杜绝了水分在炉内的循环,提高了燃烧温度,有效地降低了燃烧过程的损失,提高了锅炉效率;褐煤烟气预干燥系统的效率只有20.20%,不完善程度较大,通过优化低温炉烟抽取点至省煤器出口,可减小干燥介质混合过程的损失,从而使全厂效率提高0.33%.     

实现经济且环保的生产过程 新型干燥技术的强大功能可进一步优化生产过程

冷凝干燥技术是一种智能化的，同时也是节能的干燥工艺技术方法，即循环使用干燥空气的干燥方法。这种方法可以实现令用户在较低的温度下进行干燥。