Pd-Ag合金纳米粒子合成及其催化性能研究

采用W/O微乳液法合成Pd-Ag合金纳米粒子并结合微乳浸渍工艺制备了负载型Pd-Ag/Al_2O_3催化剂。利用紫外-可见分光光度计和透射电子显微镜对合成的Pd-Ag合金纳米粒子进行表征,并考察了对乙炔加氢反应的催化性能。结果表明,在聚氧乙烯(4)月桂醚(Brij30)/正辛烷/水微乳液体系中加入聚乙烯基吡咯烷酮(PVP),对生成的纳米粒子起到二次保护作用,Pd与Ag以合金纳米粒子形式稳定存在且粒径大小均一,粒径在1～2nm,可随PVP以薄膜形态负载并分散在Al_2O_3表面。当PVP相对分子质量为8000～10000,cPVP8:c(Pd+Ag)=0.1时,合成的Pd-Ag合金纳米粒子数量最多,粒径最小,制备的Pd-Ag/Al_2O_3催化剂具有良好的乙炔加氢活性和选择性。     

药用壳聚糖磁性复合微球的制备及特性

采用化学共沉淀法,以FeCl2·4H2O和FeCl3·6H2O为原料,氨水为沉淀剂制备出磁性Fe3O4纳米粒子;然后采用化学交联法,在分散有纳米Fe,04的壳聚糖乳液中,加入适量的戊二醛交联剂制得包覆有纳米Fe3O4的壳聚糖复合微球载体.该复合磁性微球成球性好,分散均匀,平均粒径达到10βμm左右,具有较好的磁响应性及生物可降解特性.该复合磁性微球可作为载体材料应用于磁性靶向药物的制备.     

水分散性纳米SiO_2/含氟聚合物复合乳液的制备及表征

以γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)为原料,在十二烷基硫酸钠(SDS)/OP-10复合乳化剂作用下,以氨水为催化剂制备水分散性功能化纳米SiO2粒子。采用乳液聚合法,在乙烯基功能化纳米SiO2表面接枝短氟链含氟丙烯酸酯聚合物,合成纳米SiO2/含氟聚合物复合乳液,并通过红外光谱(IR)、粒径分析、热失重(TGA)等方法表征所得产物的结构及性能。结果表明,纳米SiO2/含氟聚合物复合乳液具有较好的分散稳定性及耐热稳定性。     

反相乳液法制备海藻酸钠/壳聚糖纳米微球

分别以吐温80和复合乳化剂司盘80/吐温80为乳化剂,采用反相乳液法,以大豆油为油相,氯化钙(CaCl2)为交联剂制得海藻酸钠(ALG)/壳聚糖(CS)纳米微球。采用SEM和激光粒度分析仪对纳米微球的形貌和粒径进行表征。结果表明,采用复合乳化剂司盘80/吐温80适合油包水体系,制得的ALG/CS纳米微球粒子为球形;采用复合乳化剂比采用单一乳化剂制备的纳米微球粒径分散指数小;随着司盘80∶吐温80的质量配合比不同,微球的粒径随复合乳化剂中吐温80量的增加而减少,粒径分散指数PDI值在0.1~0.2之间;当司盘80∶吐温80质量配合比为1∶1.4时,制得的纳米微球平均粒径最小为364.4nm;当司盘80∶吐温80质量配合比为1∶0.2时,制得的纳米微球平均粒径最大为1171nm。     

负载型纳米Pt颗粒的制备及催化性能研究

通过分散共聚制备了聚N-异丙基丙烯酰胺接枝聚丙烯腈/聚苯乙烯(PNlPAAm-gPAN/PSt)聚合物微球,以氯铂酸(H2PtCl6)为金属源,乙醇为还原剂,将与酰胺基团配位的铂离子(Pt4 )还原成纳米铂(Pt)颗粒,负载在表面具有特殊形态的聚合物微球表面,制得了分散稳定的负载型纳米Pt颗粒,可用于催化苯胺的聚合等,通过改变反应温度可控制苯胺的聚合速率.     

负载型纳米Pt颗粒的制备及催化性能研究EI北大核心

通过分散共聚制备了聚N-异丙基丙烯酰胺接枝聚丙烯腈/聚苯乙烯(PNIPAAm-g-PAN/PSt)聚合物微球,以氯铂酸(H2PtCl6)为金属源,乙醇为还原剂,将与酰胺基团配位的铂离子(Pt4+)还原成纳米铂(Pt)颗粒,负载在表面具有特殊形态的聚合物微球表面,制得了分散稳定的负载型纳米Pt颗粒,可用于催化苯胺的聚合等,通过改变反应温度可控制苯胺的聚合速率。     

金属纳米粒子/微管簇碳纤维复合材料的合成与研究

借助原位还原法,成功地将铂纳米粒子负载在一种具有微管簇形貌的植物载体-剑麻纤维中,负载的铂纳米粒子的平均粒径约为3.6nm.通过在400℃下碳化这种含有铂纳米粒子的剑麻纤维,得到铂纳米粒子/碳纤维复合材料,这种碳纤维保留了原来剑麻纤维的微管簇形貌.剑麻纤维中相邻的微管壁和它们所夹的胞间层在碳化反应之后,融为一体,变成了均一的碳微管壁.虽然碳化后铂纳米粒子的平均粒径增大到5.3m左右,但是生成的载体碳纤维还是有效地阻止了铂纳米粒子的生长.这种铂纳米粒子/碳纤维复合材料兼具微管簇结构、碳纤维载体和活性铂纳米粒子的优点,很可能成为一种新型的异相催化剂,在很多领域中具有开发前景.     

前驱体对水性PU/SiO_2复合材料结构与耐水性能的影响

在阴离子水性聚氨酯分散体(WPU)存在下,通过前驱体正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)的共水解缩合反应,在m(前驱体)/m(WPU)为1时制备出WPU/SiO2(WPUS)复合材料。研究了n(MTES)/n(TEOS)对WPUS复合乳液平均粒径及粒子形貌、膜表面形貌及耐水性能的影响。结果表明,随着n(MTES)/n(TEOS)由0增大到1.5,复合乳液平均粒径由130 nm逐渐减小为107 nm;没有加入MTES的乳液中SiO2粒子以无规则形态非均匀分布,而加入MTES后乳液中SiO2为均匀分布的规则球形;随n(MTES)/n(TEOS)增大,复合膜表面SiO2分布均匀度逐渐提高,表面粗糙度逐渐减小,同时膜的水接触角逐渐增大,吸水率逐渐下降。     

氧化硅包裹四氧化三铁微球的制备及表征

在室温下,采用H2O2氧化Fe(OH)2悬浮液的方法制备得到了粒径23nm左右的磁性纳米粒子,经X射线衍射检测制备得到的是Fe3O4磁性纳米粒子,粒子的饱和磁化强度为59.05emu/g。先用硅烷偶联剂KH560修饰Fe3O4,提高粒子在乙醇溶液中的单分散性,在此基础上采用溶胶凝胶法通过TEOS水解制备得到分散性佳、尺寸均匀、粒径为25nm左右核壳结构的氧化硅包覆Fe3O4纳米粒子的磁微球。     

CTAB/丁醇/庚烷/水四组分微乳液稳定性研究及BaF2纳米粉体制备

本文用CTAB/丁醇/庚烷/水四组分微乳液体系沉淀制备纳米BaF2.研究了体系中丁醇和CTAB的质量比、庚烷质量、含水量及溶质对微乳液体系稳定性和产物BaF2沉淀粒径、分布的影响.稳定的Ba(NO3)2微乳液和NH4F微乳液混合制得10nm的BaF2颗粒,单分散性好,颗粒呈球形.BaF2粒径大小和分布随CTAB和水质量比值的增大而减小.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to     

Win-Win Cooperation

正The Chinese Premier Li Keqiang's recent trip to the UK has reinforced the China-UK comprehensive strategic partnership;just as the British Prime Minister David Cameron put it,"the relationship is gaining in strength,depth and understanding"after a bucket of business deals being inked worth more than 30 billion US dollars.From the first agreement signing in 2004 to the new agreement of mutual standards recognition and adoption in     

Systematic Approach for Emerging Industry

正A national directory of standards complexes for strategic emerging sectors was recently developed and released jointly by 12governmental departments,namely,SAC,NDRC,MOST,MIIT,MEP,MOA,AQSIQ,State Forest Administration,State Administration of Science and Technology for National Defense,State Oceanic Administration and National Railway Administration.     

Strictest Pollutants Emission Standards

正Four new national standards on air pollutant emission control offi cially issued by the Ministry of Environment Protection(MEP)together with AQSIQ and SAC has been brought into force from July 1,2014.The Emission standard for air pollutants of coal-burning,oil-burning and gasfi red boilers,which is the strictest emission standard historically,will tackle the stubborn pollution problem of boilers and waste incineration in most of China’s regions.     

Instructions to Authors

New Carbon Materials is a bimonthly journal published with the permission of the Ministry of Science and Technology and of the State News and Publication Agency.The journal is sponsored by the Institute of Coal Chemistry,Chinese Academy of Sciences,and is published by Science Press.Aims and Scope     

Progress on Standards Copyright Protection

正Recently,National Copyright Administration of China(NCAC)has rewarded 215 organizations and 179 individuals for their outstanding efforts on investigating standards copyright infringement and piracy in 2013.Hua Jianhua,the Deputy-Director of National Standards Copyright Protection Workgroup Office won a third prize of the national individual award.In 2012,SAC set up the national standards copyright protection working group,and developed policies to crack down standards infringement and piracy behaviors and to strengthen standards copyright protection.