溶胶-凝胶法制备钇掺杂氧化锆的工艺研究

论述了用溶胶-凝胶法制备钇掺杂的氧化锆前驱体的过程,系统地研究草酸溶液的浓度、pH值、加热温度以及添加方式对溶胶、凝胶的影响,得出制备氧化锆前驱体的最佳工艺条件:当氧氯化锆溶液与草酸溶液的浓度比为1.25～2,草酸溶液pH值为1～2,加热温度为40～80℃,制得的前驱体溶胶、凝胶均匀,透明.正加方式得到的溶胶淡蓝色透明,较反加方式下的溶胶的胶凝时间短.并对最佳工艺条件制备的粉体进行SEM分析,结果表明,很好地合成了钇掺杂的纳米氧化锆粉体.     

溶胶-凝胶法制备纳米Y2O3粉体

为了改善Y2O3粉体的分散性,提高其烧结活性,试验以三乙醇胺和氨水为凝胶剂,利用溶胶-凝胶方法合成了纳米级Y2O3粉体,采用差热/热重、X射线衍射、透射电镜研究了前驱体的组成、前驱体在不同的煅烧温度下的物相变化以及煅烧粉体的分散性.结果表明,前驱体的组成为Y2(OH)5.14(NO3)0.86H2O,在500℃保温2h可直接生成立方相的Y2O3,煅烧至1000℃保温2h得到了结晶度高、分散性好、平均粒径为50nm、近球形的YO纳米粉体;三乙醇胺的加入有利于提高YO粉体的分散性.     

尖晶石型Ni0.8Zn0.2Fe2O4纳米晶体的?制备及电磁性能研究

以金属离子的柠檬酸盐为前驱体,通过sol-gel自燃烧的合成方法制备了镍锌铁氧体(Nio.8Zno.2Fe2O4)纳米晶体.采用FT-IR、DSC-TG、XRD、TEM波导等方法对产物以及产物的电磁性能进行了表征.结果表明,在前驱体中,金属离子与柠檬酸以络合物的形式存在.凝胶在220℃完成自燃烧反应.随着热处理温度的升高,粉体的粒径逐渐增大.纳米晶体在8～12GHz的测试条件下具有介电损耗与磁损耗.随着涂层厚度的增加,混合媒质的微波反射率逐渐增加,反射率吸收峰随着厚度的增加向低频移动.     

纳米LaAlO3粉体的制备与烧结

对共沉淀法制备纳米LaAlO3粉体及烧结进行了初步研究．采用La(NO3)3与Al(NO3)3为原料，控制pH=9左右，在室温下完成共沉淀，前驱体经800℃／2h的条件下煅烧后可获得纳米LaAlO3粉体，粉体颗粒约50nm．无压烧结的结果表明，这种纳米LaAl03粉体的烧结性能较好，通过选择适当的条件，在1500℃下烧结可获得密度达6．2g／cm^3的LaAlO3材料．     

拓展作用光范围的纳米TiO2-xNx制备和表征

以廉价的工业偏钛酸为原料,采用特殊的酸解工艺制得纳米级水合二氧化钛粉体,再利用高温管式炉对前驱体-TiO2·nH2O进行掺氮,制得纳米TiO2-xNx粉体,研究了不同掺氮气体和反应工艺对TiO2-xNx粉体吸光特性、形态结构的影响.结果表明水合TiO2粉体与氨气在600℃下反应5h,制得的粉体为锐钛矿型结构,粒径约为20nm,光吸收阀值由387nm红移至520nm左右.     

反应条件对水热法制备纳米ATO粉体形貌和电性能的影响

以SnCl4·5H2O和SbCl3为原料,采用水热法制备出了纳米级锑掺杂二氧化锡(ATO)导电微粉,运用XRD和TEM等测试手段对粉体进行了表征,比较系统地研究了掺杂量,共沉淀温度,溶液pH值,水热时间、温度和表面活性剂对粉体粒度、形貌和电性能的影响规律.研究表明,合成的ATO粉体分散性较好、导电性能优异,粒径在10nm左右,具有金红石型结构.在ATO纳米导电粉的制备过程中,前驱体制备温度对其性能有很大影响,当共沉淀温度在40-50℃时制得的粉体导电性能最佳.水热条件对粉体的形貌、粒度和导电性也有较大的影响,在200℃,4h,pH=2～4条件下可以制得导电性能良好的ATO粉体,所添加的表面活性剂可以改善粉体的粒径和分散性能,但对粉体的导电性影响极小.掺入Sb3 的量对载流子的迁移率有很大的影响,在掺杂浓度为4～5%左右可制得导电性极佳的纳米ATO粉体.     

纳米TiO_2复合抗菌材料的制备及其性能研究

采用溶胶-凝胶技术,以钛酸正丁酯为前驱体,于450~700℃的空气气氛中煅烧3h,分别制得了有、无SiO2包膜的掺杂银、镍金属离子的复合纳米TiO2抗茵粉体.采用TG-DSC、XRD、SEM等方法对产物进行表征,并选用大肠杆茵、枯草芽孢杆茵为受试菌种,采用抑茵圈实验对粉体抗茵性进行检测.结果表明,在该实验条件下制备的纳米TiO2>为锐钛矿型,通过包覆SiO2能有效地减小SiO2的粒度,防止团聚的产生,粉体抗茵性能良好,无SiO2包膜的抗茵粉体抑茵效果优于有包膜的抗茵粉体,在700℃下煅烧的抗茵粉体抑茵效果最好.     

锐钛矿型纳米TiO_2粉体的纯净制备

以钛酸丁酯为原料,采用可控醇盐水解沉淀法制得TiO2前驱体,450℃恒温煅烧2h后制备出粒径约10nm的纳米TiO2粉体,并与传统溶胶-凝胶法制备的TiO2纳米粉体的形貌、结构、工艺过程进行了对比.结果表明,可控醇盐水解沉淀法可制得纯度高、粒径小且分布范围窄的纳米TiO2粉体,工艺简单,流程最短.该方法的关键是实现了醇盐的可控水解.     

γ-Fe2O3/SiO2纳米复合粉体的制备

以硝酸铁和正硅酸乙酯分别作为氧化铁和SiO2的前驱体,通过溶胶-凝胶工艺制备了γ-Fe2O3/SiO2纳米复合粉体.若使用氯化铁为氧化铁前驱体,SiO2基体中则会生成α-Fe2O3.当干凝胶热处理温度较低时(T＜400℃),复合粉体(硝酸铁为前驱体)以非晶态存在.当T达到600℃时,γ-Fe2O3粒子在SiO2基体中大量形成.随着热处理温度的进一步升高,粉体中开始有α-Fe2Oa杂质生成.使用盐酸做添加剂对复合粉体中γ-Fe2O3粒子大小及颗粒尺寸分布均有显著影响.     

溶胶-凝胶法制备纳米Si_3N_4(Y_2O_3)粉末的研究

本文以硅溶胶、尿素和炭黑为原料，采用溶胶-凝胶碳热氮化法在1500℃、2h条件下制得粒径为50～80nm的Si3N4纳米粉末．比较了由硅溶胶与尿素经氨解合成的前驱体和硅溶胶二种不同起始物料的反应活性，研究了氮化条件对合成反应的影响．结果表明：氨解前驱体使硅溶胶中的结构水排除，有助于加快反应速率，提高产物氮含量．本文同时以Y（NO3）3为添加剂，在溶液状态与硅源混合，合成了Si3N4－Y2O3纳米复合粉末.     

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.