电击防护的安全限值

为了减小直接接触危险带电零部件产生电击危险的可能性,分析了基础安全标准和相关专业安全标准对操作人员可能触及到的接触电流值、电压值和电容放电量等安全限值的具体规定,指出安全限值的选择应符合基础安全标准的要求,并考虑设备的应用条件和环境条件.     

屋面系统帮助马来西亚降温

很多马来西亚人一觉得浑身发热，自上出汗、开始发黏，就会赶紧去冲个凉水澡。统计数字表明，马来西亚一半的人口，超过一千万的人都生活在“热房子”里。但是大多数人并不知道，引起这一问题的真正原因常常是屋面系统。     

安徽省博物馆

一、项目背景安徽省博物馆是安徽省唯一一座集自然、历史、社教为一体的省级综合类博物馆,依托安徽文物大省的资源优势,收藏甚丰,藏品具有很高的历史、科学、艺术价值和鲜明的地方特色。博物馆老馆建于20世纪50年代,由于年代久远、空间局促,已经     

定量分析在IT项目管理中的应用研究

本文从IT项目管理的内容出发,阐明了基于项目管理的IT软件开发过程,并在总结IT项目自身特性的基础上,得出引入定量分析的重要性和必要性.同时,还列举出定量分析在IT项目管理中的应用领域.     

电脑走进大巴山区

我在祖国边疆工作,每隔两三年就要回到地处大巴山区的农村家乡休一次假。几十年来,每回去一次,家乡都有新的变化,实在令人欢欣鼓舞。　　最近回老家休假,我发现乡变化特别大,家家户户都有电视,彩电占30% 以上。有的人家安装了直拨电话。我过去回家,与边疆的亲朋好友或单位领导联系,写封信往返要一两个月,现在,可立等通话,非常方便。有的人家买了VCD:香港武打片、台湾生活片、新加坡言情片、美国战争片......应有尽有,随你挑选。老百姓上街“赶场”,也不用走路了,可以骑自行车、摩托车,或乘四轮车、公共汽车......这一切,…     

Quantitative study of the effect of electromagnetic field on scale deposition on nanofiltration membranes via UTDR

Ultrasonic time-domain reflectometry (UTDR) as an in situ, non-invasive real-time technique has been successfully utilized to quantify membrane fouling and cleaning. This study describes an existing ultrasonic technique for quantitative study of the effect of magnetic fields on CaCO₃ scale deposition on the membrane surface during crossflow nanofiltration (NF). The fouling experiments were conducted with CaCO₃ solution containing Ca²⁺ of 1.8 and 3 mmol/L. The experimental electromagnetic field (EMF) was 0.02 T. A commercial NF membrane and a highly sensitive ultrasonic sensor were used in all the experiments. Results show a good relationship between the ultrasonic measurements and the development of CaCO₃ scale on the NF membrane surface. An increase in the amplitude of differential signal with operation time results from the deposition of the CaCO₃ scale layer. In addition, the movement of the differential signal in the time domain observed is associated with an increase in the thickness of the fouling layer. The UTDR technique is capable of measuring the rate of fouling layer formation under different treatment conditions, i.e. with non-magnetic field (NMF) and EMF. Scale layer of deposited CaCO₃ obtained in the experiment with NMF is denser and thicker than that with EMF. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses imply that the magnetic treatment suppresses the formation of calcite crystals and prefers vaterite and aragonite. Furthermore, the ultrasonic technique is sensitive to the different fouling rate between experiments carried out with 1.8 and 3 mmol/L CaCO₃ solutions. The thickness of the fouling layer measured by weight measurement is consistent with that obtained by UTDR in real time. The thinner and less dense scale layer is the main reason for the slower flux decline. Overall, independent measurements such as the flux-decline data, SEM analysis and weight measurement corroborate the ultrasonic measurements.     

轻型建筑玻璃

总部位于德国的聚碳酸酯透明建筑构件制造商乐得卡将在本年度展览会上首次进行其产品展示，届时将有众多新产品参加展览，其中之一就是可用于建筑内墙，天花板，外部屋顶以及天棚的PC 2216-2聚碳酸酯玻璃构件。乐得卡公司还开发了一种同时可用于内部和外部工程的双色玻璃建筑构件。     

混凝土小型空心砌块填充墙裂缝的原因及防治

本文从混凝土小型空心砌块的材料力学性能、建筑物砌体的设计和砌块的施工等方面进行分析,提出了可操作的防裂技术措施。     

普林斯顿公共图书馆

新建的普林斯顿公共图书馆是为该地区多元化且教育程度良好的社区大众而设计的。正如该图书馆主任所说的那样，它已经成为了一个“新时代的社区集会中心”。该图书馆坐落于普林斯顿市中心，它是其所取代的旧图书馆的两倍大小。当前，它已经成为了这一充满活力的社区的重要组成部分．并对周围市中心地带起到了积极的催化剂作用。