Unseen science? Representation of BRICs in global science

A survey of scientific periodical publications (or venues-as distinct from articles) from BRIC country practitioners counted more than 15,000 national publications. Data collected from and about Brazil, Russia, India, and China (BRIC countries) show that 495 venues, or about 3%, are listed in the Science Citation Index Expanded^© (SCIE^©) in 2010. Contrary to our expectation of under-representation overall and coverage limitation of SCIE, the average percentage of SCIE-listed venues for the BRICs is about the same as that for advanced countries. China has the lowest representation of national venues in SCIE at 2% of all publications; Russia has the highest at about 8%. India has about 6% of venues in SCIE; Brazil has about 4%. In other words, SCIE includes about the same percentage of high quality science from these four countries as for North America and Europe, meaning that these countries are not under-represented in SCIE. Moreover, the number of national venues available as outlets suggests that national scientists in these countries have good access to publications and venues. Some of the BRIC national publications are difficult to “see” at the global level because of language barriers, diverse publication formats, and lack of digitization. Other national differences represent historical traditions surrounding publication.     

FE parametric study of RWS/WUF-B moment connections with elliptically-based beam web openings under monotonic and cyclic loading

International Journal of Steel Structures - This paper provides numerical results investigating the behaviour of steel web-perforated beams with different shaped single openings located close to...     

The design and fabrication of a monodisperse aerosol generator

Abstract

A monodisperse aerosol generator using a dual stream carrier gas designed and built for combustion research is described. Tetralin is used as the working fluid to generate the mist. The system is capable of generating monosize droplets of diameters between 7 μm to 58 μm. The stability of the system can be maintained up to 4 hours with a typical monodispersity of 0.12.     

指数故障/维修背景下串联系统可用度置信限

系统可用性是综合反映系统可靠性及维修性的一种测度,如何利用现场获取的各组成单元的故障数据和维修数据进行系统可用性综合及评定恰是可靠性及维修性工程中的难题。考虑到串联模型具有普遍性以及指数信息更具通用性的工程背景,依据信息等价转换原则,从现场记录中提取、挖掘或折算出以时间和次数为特征的指数故障和指数维修的基本信息,并探讨了指数故障/指数维修的串联可修系统可用度概率估计的数值解析方法。基于极大似然估计深入研究了经典方法的置信区间;基于Bayes定理深入研究了单元和系统可用度一阶矩、二阶矩,又利用不完全Beta函数、β分布与F分布分位数间的关系,最终求解出串联可修系统可用度的经典近似置信限和Bayes近似置信限,研究成果有效地解决了串联可修系统可用性综合及评定的难题。这两种方法可适用于所有串联模式的复杂机电系统,而且伴随系统的运行,各组成单元故障/维修数据信息也在发生变化,据此可以实时地进行可修串联系统可用性综合及评定。以我国某风电厂风力发电机组为工程应用实例,验证了该方法的可行性与适用性。     

张家界市建筑形象建设规划浅探

张家界是我国著名的风景旅游度假城市，当前，围绕转型提质，张家界正加快推进相关基础设施建设。在这一过程中，一度由于缺乏总体规划而出现建筑形象的杂驳失衡，对城市形象造成了负面影响。本文将以打造山水景观旅游度假城市为标准，对张家界城市建筑的形象与风格进行粗浅的规划研究。     

350MW超临界机组锅炉过热蒸汽喷水减温控制策略分析

以某台350 MW超临界机组为例,介绍了锅炉过热蒸汽喷水减温控制策略的设计原理、实现方法及特点,分析了超临界锅炉过热蒸汽温度控制策略采用的惰性区和导前区温差函数变换、负荷变比例增益控制器、负荷和末级过热器出口温度微分前馈、过热度保护等控制手段,并与亚临界机组普遍采用的串级汽温控制策略和导前汽温微分信号的双回路控制策略进行了比较。     

原位聚合法制备具有长链支化的三元乙丙橡胶

采用铁系催化剂制备了具有1,2-结构的聚丁二烯,然后在钒系催化剂存在下进行乙烯和丙烯共聚合,原位合成了以聚丁二烯为第3单体的三元乙丙橡胶。并使用核磁氢谱、傅里叶变换红外光谱、三检测器系统凝胶渗透色谱联用仪和热重分析仪对所得的聚合物进行了表征。结果表明,聚丁二烯的质量大于1.0 g时,催化剂聚合活性缓慢降低。随着聚丁二烯用量的增加,相对分子质量增大,相对分子质量分布变宽。VOCl3-Al2(C2H5)3Cl3-ETCA催化体系中,当n(Al)/n(V)=60,n(ETCA)/n(V)=15时,以聚丁二烯作为第3单体具有最高的聚合活性。新型三元乙丙橡胶中既含有可用于硫化的双键,又具有一定量的长链支化结构,具有潜在的工业应用前景。     

基于移动终端的EPC识读煤矿安全系统的设计与实现

针对煤矿安全生产的信息化管理问题,本文提出了一种基于移动终端的EPC识读系统,它是基于广泛应用的移动终端上所开发的一种系统,可实现在移动终端上进行人员查询、统计、考勤和定位等管理功能。