Applications of single-atom catalysts

Owing to unsaturated coordination environment,quantum size effect and metal-support interaction,single-or dual-atom metal sites,such as Mn,Fe,Co,Ni,Cu,Zn,Mo,Ru,Rh,Pd,Ag,Sn,Ir,Pt,Au,Bi,and Er coordinated with nonmetallic elements such as O,N,P,and S,exhibit different electronic configurations,which endow them with high catalytic performances in multiple redox reactions and versatile applications in organic synthesis,environmental remediation,energy conversion,and biomedicine.Despite intense research,the relation of structure-activity for single-atom catalysts(SACs)still bedazzles researchers,since diversified configurations of active sites would bring about difficulty in structural identification and theoretical simulations.Here,recent results on the applications of SACs are reviewed with an emphasis on identifying the active sites and discussing the relation between structure and property.     

朋友

正像往年新年一样,收到了许许多多同事、同仁、朋友、合作者的祝福短信和贺卡。短信的词汇或长或短,或转发或原创,斑斓多彩,丰富感人,让人温暖兴奋,看不释眼;贺卡或豪华或简朴,或来自遥远的异地,或来自咫尺的近邻,让人感到其中的牵挂、祝福,爱不释手。不论老友新朋,见字如人,回味绵长。我越来越觉得,看短信比看春晚更热切,更有意义,更令人慰藉。特别是在寒冷的冬天里,在全球的危机     

春节特别奉献2012

辞旧迎新,一年一度的春节很快就要来临,在此,我们提前给读者拜年,祝大家新春快乐,合家幸福,万事如意。春节前夕,采办年     

宠物也需“标准生活”

“我睡觉的时候,只要一关灯,抱抱就会出现在枕头边上,我掀开被子,抱抱就钻进来,转个身,紧紧靠着我睡,脑袋枕在我胳搏上,两手还伸开,跟我睡得一模一样。大冷天的,这样的肉麻很让人陶醉。有一次,我躺下的时候抱抱在吃夜宵,等他反应过来,我已经躺踏实了。他跑过来,仔细看了看我,确认我双眼紧闭呼吸均匀,以为我睡着了——其实我是故意的,要搁以前,他会叫两声,把我喊醒重睡。可这次,他竟然没言声,自己在被子上踩了个坑,躺下了。这不就是懂事么？我忍都忍不住,伸手就把他薅进被窝。”     

编委风采

潘复生1962年7月生,浙江兰溪人,工学博士,教授,博士生导师,重庆市科学技术研究院院长,国家镁合金材料工程技术研究中心主任,国家973项目专家组组长,国务院学位委员会学科评议组成员,日本千叶大学客座科学家,英国伦敦大学访问教授。     

普通砖混住宅结构设计经验谈

一、结构设计总说明 　　主要是设计依据,抗震等级,人防等级,地基概况及其承载力,防潮层做法,活荷载取值,材料强度等级,施工中的注意事项,选用详图,通用详图或节点,以及在施工图中未画出而通过说明文字来表达的信息.……     

胜达集团

胜达集团有限公司总部在杭州市萧山经济技术开发区,集团自1983年建厂以来,抢抓机遇,锐意改革,走出了一条“从包强包,多业并举”的科学发展之路,目前,全集团拥有总资产逾25亿元,净资产超20亿元,员工6000多名,形成了以纸包装为主业,涉及纺织,生活用纸,房地产,化工,钢构及物流保税等跨地区,跨行业,集科,工,贸为一体大型企业集团公司,2007年,全集团完成产值46.08亿元。     

涡阳警方端掉两个传销窝点10人被刑事拘留

正2013年12月26日凌晨4时,安徽省涡阳县公安局经侦大队会同城区派出所、县工商局、综治办等单位共计150余人,在前期缜密侦查的基础上,统一行动、雷霆出击,前往西郊孙楼居委会清查了11处传销人员居住的出租屋,一举打掉两个大型传销窝点,现场查获涉嫌传销人员80余人,截至目前,共刑事拘留犯罪嫌疑人10名,治安拘留6名。经查,自2012年6月以来,江苏省丰县李某伙同湖南省株洲易某等人,以销售湖北省武汉某品牌化妆品为名,以每套产品4100元的价格,采用欺诈、诱骗、拉人头等方式,将     

听殷承宗的钢琴协奏曲《黄河》

“风在吼,马在叫,黄河在咆哮,黄河在咆哮……” 太熟悉了,这气势磅礴的呐喊,这昂扬斗志的旋律,早在1939年春天就已经响彻云霄,传遍弥漫着抗日烽火的中华大地。由光未然作词、人民音乐家冼星海作曲的《黄河大合唱》,曾激励过多少抗日儿女奔赴前线,浴血奋战,保卫家乡,保卫黄河。     

今秋月饼包装闲谈

岁岁中秋年年过,一年更比一年“火”。上海街头,无论是大超市,还是食品店,都争先恐后推出月饼专柜,放眼包装,更是千姿百态,大开眼界。纸盒、铁盒、钙塑盒、铝盒、不锈钢盒、中密度板盒、竹编盒、红木盒。琳琅满目、气象万千,至于内衬丝绒,大盒装小盒、纸盒套铁盒,甚至镶金嵌银也屡见不鲜。报载,广州某居民收到一盒“巨无霸”月饼,     

驾驶员对异色物体动态距离判识对比

为研究在动态环境中,颜色因素对驾驶员空间距离判识的影响,本文选用32名驾驶员在不同深度距离和车速条件下,进行实际道路试验.驾驶员分别在昼间、黄昏和夜间对不同颜色障碍物空间距离进行判识,分析检验判识结果.结果表明:在地面动态环境中,白天不同颜色距离判识差异不显著,黄昏随着环境照度下降,判识差异显著,夜间使用灯光照明时,距...     

The under-representation of women in information technology and computing in the Middle East: A perspective from Jordan

This paper presents the results of a study on the participation of women in computing and information technology (IT) in Jordan. It investigates the percentages of women at all levels of education—from the secondary level through the graduate level—and their participation in the IT workforce. Women in Jordan are still under-represented in the computing and IT fields, and my study explores possible reasons for the under-representation and what can be done to increase women's participation. Despite the fact that the worldwide participation of women in computing has been declining steadily to very low levels, that is not the case in Jordan. This study found that the percentage of Jordanian women in the IT field is rising and far exceeds that of women in the U.S. and Canada. Indeed, increasing women's participation in computing in Jordan is vital to the economy and to the country's sustainable development.     

Experimental investigation of oil retention in air conditioning systems

In air conditioning and refrigeration systems a small amount of oil is carried with the refrigerant and is retained in the system components. Oil retention characteristics in the condenser, evaporator, liquid and suction lines were measured and are presented and discussed here. Refrigerants R22, R410A, and R134a with miscible and non-miscible lubricants were considered to investigate oil retention physics in the widest possible range of transport properties. A parametric analysis in the suction line showed that oil retention depends on the oil mass fraction, vapor refrigerant mass flux, mixture viscosity ratio and orientation of the pipe. In the suction line, an increase in mixture viscosity of about 55% caused a rise in oil retention in the range of 50%, depending on the oil mass fraction. Oil retention in the upward vertical suction line is about 50% higher than in the horizontal line at similar conditions.     

21世纪之初工程哲学在东西方的同时兴起

科学哲学和技术哲学都是首先在欧美国家兴起的,可是,工程哲学却是于21世纪之初在中国和欧美发达国家同时兴起和基本同步发展的。文章简要介绍了2002年以来工程哲学在中国和欧美国家发展的重要事件和已经发表的重要著作,最后,简要评论了东、西方工程哲学发展的主要特点。     

驾驶员与儿童事故倾性研究

文章通过对全国部分城市驾驶员交通事故和儿童意外伤害事故的流行病学研究结果发现：（１）驾驶员交通事故和儿童意外伤害事故检出率不存在地区性差异；（２）驾驶员交通事故和儿童意外伤害事故的检出率无显著性的年龄差异；（３）不同年龄段驾驶员和儿童，男性事故检出率均高于女性事故检出率；（４）极少数的事故人群具有事故倾向性：在驾驶人群中有６％～８％的事故倾性驾驶员，其引起的交通事故数占总事故数的３０％～４０％，在１～１４岁儿童中有１％～２％的事故倾性儿童，其发生的意外伤害数占意外伤害总数的２５％～３５％；（５）事故倾性驾驶员和事故倾性儿童再发事故的比率均比对照组高。文章从流行病学角度证实了事故倾性人群的存在，并对事故倾性的本质作了初步探讨。     

线切割单晶硅表面损伤的研究

利用台阶仪、扫描电镜（ＳＥＭ）和Ｘ射线双晶衍射仪,研究了线切割硅片和内圆切割硅片的表面切割损伤和损伤层厚度。实验指出线切割硅片表面粗糙度大,外表面损伤大,但损伤层的厚度要小于常规内圆切割硅片。初步讨论了影响线切割硅片表面损伤的原因     

Packaging production and consumption in the world and in some industrialized countries

This paper reports on statistics concerning production and consumption of packaging (as a whole or per capita) in Europe, in the USA, in Japan and in the world. Data have been provided by National Trade Associations and by consultants specialized in packaging and in economics. It is estimated that in 1986 the global consumption of packaging reached 150 millions of tonnes valued at 1200 billions of French francs. Consumption could reach 247 million tonnes by the year 2000. Paper and board have the highest consumption rate, but plastics have the highest rate of growth. Nevertheless, consumption per capita in the industrialized countries will be more than 10 times the consumption in underdeveloped countries. The packaging industries take fourth place in the USA, sixth in Western Germany and twelfth in France. In Europe, as in the world, paper and board is the material most used (40%), with glass (a high density material) taking second place and plastics third, i.e. if we consider the quantity of materials and not their value. Some differences appear between the various countries, but the figures for USA and Japan lead to similar conclusions. The survey shows clearly that the USA as compared with Europe has twice the consumption of packaging materials per capita and this difference is even greater compared with the rest of the world.     

Air separation and liquefaction: recent developments and prospects for the beginning of the new millennium

Earlier advances in air separation and liquefaction include improvements in: overall product recovery, feed air purification, more efficient heat exchange, optimum plant control, gradual improvement in efficiency of compressors and expanders. More recent improvements include use of structured packing in distillation columns, molecular sieve adsorbents for air purification, computer simulation and control of plants, and increased machinery efficiency. Advances in fabrication and construction techniques are aimed at reducing capital costs. This paper reviews modern developments in air separation and liquefaction and attempts in this context to suggest features that might be expected to arise in the early part of the third millennium.     

Geography,Race and the Malleability of Man: Karl von Baer and the Problem of Academic Particularism in the Russian Human Sciences

The question of national specificity in science was vigorously debated in 19th century Russia and remains relevant to the geographical and cultural contextualization of scholarship. This article introduces the term academic particularism to denote this phenomenon and addresses it through an examination of the career, ideas and legacy of Karl von Baer in the fields of geography, ethnology and physical anthropology. The article traces significant shifts in Baer's interests and views after his relocation to Russia in 1835 and identifies a cluster of key ideas present in Baer's work in the mid‐19th century that were further developed by subsequent scholars in the late 19th century and came to constitute a distinctive strain in the Russian human sciences.