纳米晶钛酸锶钡(Ba0.5Sr0.5TiO3)粉体的微波水热合成

采用微波水热法合成了纳米晶钛酸锶钡(Ba0.5Sr0.5TiO3)粉体,通过XRD、TEM、SEM等分析手段表征粉体,研究了微波水热合成反应温度、时间和前驱物浓度对反应产物形貌、粒度的影响,获得了制备纳米晶钛酸锶钡粉体的最优工艺参数.实验结果表明:在微波水热反应温度为195℃、反应时间20～30min、前驱物浓度为0.16mol/L时获得的粉体粒径小而且均匀,粉体平均粒度为60nm.     

氧化硼掺杂钛酸锶钡梯度陶瓷致密化及介电性

研究了氧化硼(B2O3)掺杂量及烧结温度对钛酸锶钡(Ba1-xSrxTiO3，x=0～0．4)致密化行为及其微观组织的影响，确定了不同成分钛酸锶钡中氧化硼掺杂量．随后，采用一系列Ba1-xSrxTiO3掺杂粉体，烧结制备了钛酸锶钡梯度陶瓷，并测试了其介电性能．结果表明，钛酸锶钡掺杂适量氧化硼明显降低烧结温度，在1300℃即可烧结致密化，比未掺杂相同成分的钛酸锶钡陶瓷烧结温度至少降低100℃；烧结后各成分单层陶瓷与梯度陶瓷介电性能随温度的变化表明，梯度组成陶瓷的居里峰温度区间显著展宽，大大降低了该温区的介温系数，可望提高该系列陶瓷元器件精度及稳定性。     

表面活性剂对溶胶-凝胶法制备Ba0.6Sr0.4TiO3粉体的影响

钛酸锶钡(BST)陶瓷是一种性能优异的电容器材料、热敏材料和铁电压电材料,具有非常广阔的应用领域.采用溶胶-凝胶法合成了Ba0.6Sr0.4TiO3纳米粉体,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、激光粒度分析仪对粉体的物相组成、颗粒大小和形态进行了分析,利用红外光谱仪(FT-IR)研究了表面活性剂在合成纳米Ba0.6Sr0.4TiO3过程中的作用,并重点考察了表面活性剂对Ba0.6Sr0.4TiO3粉体性能的影响.研究结果表明,通过添加适量的表面活性剂能有效改善纳米钛酸锶钡粉体的表面性能,使纳米钛酸锶钡具有较好的分散性,可充分发挥材料的纳米效应.     

溶胶—凝胶法制备纳米钛酸锶

采用溶胶－凝胶方法,从Ｓｒ（ＡＣ）２－Ｔｉ（ＯＣ４Ｈ９）４－Ｈ２Ｏ－ｉｓｏＣ３Ｈ７ＯＨ体系中合成了钛酸锶粉末。ＤＴＡ和ＸＲＤ的分析结果表明,在５００℃时,开始有立方晶相的ＳｒＴｉＯ３生成;反应在８００℃基本完成,由Ｓｃｈｅｒｒｅｒ公式计算,粒径在４７．１ｎｍ到４９．７ｎｍ之间。ＤＴＡ和ＦＴ－ＩＲ分析结果表明,锶离子和酸根离子均匀地分散于凝胶基体之中,我们还研究了反应物、溶剂等因素对形成钛酸锶凝胶的     

液相法制备钛酸锶钡粉体的研究进展

液相法是制备性能良好的钛酸锶钡粉体的有效方法.介绍了国内外近年来液相法合成钛酸锶钡的研究现状及其进展,重点介绍了几种基本的液相合成法:化学沉淀法、溶胶-凝胶法、水热合成法、喷雾热解法和燃烧合成法,比较了其优缺点,对基本液相法的新进展进行了简要介绍,并对进一步的研究方向和发展趋势提出了见解.     

化学气相沉积法制备SiC纳米粉

本工作采用二甲基二氮硅烷和氢气为原料，在１１００－１４００℃温度条件下，通过化学气相沉积制备出了高纯、低氧含量的纳米ＳｉＣ粉体，实验结果指出，在１１００－１３００℃，制备得到的粉体颗粒由于锭型相和β－ＳｉＣ微晶组成；而在１４００℃则粉体颗粒主要由β－ＳｉＣ微晶无序取向组成，随反应条件的改变，粉体平均粒径和β－ＳｉＣ微晶的平均尺寸分别在４０－７０ｎｍ和１．８－７．３ｎｍ范围内变化，同时，产物粉体的Ｃ     

共沉淀法制备YAG-Al2O3纳米复合粉体

本文采用共沉淀法制备了ＹＡＧ－Ａｌ_２Ｏ_３纳米复合粉体．并通过ＸＲＤ、ＴＥＭ详细研究了粉体组成、形貌随煅烧温度的变化．研究表明,在１３００℃下煅烧可获得ＹＡＧ粒径约１００ｎｍ、分散均匀、无杂相的ＹＡＧ－Ａｌ_２Ｏ_３纳米复合粉体．粉体在１４５０℃可热压烧结致密,远低于文献报道的热压烧结温度１６００℃．用共沉淀法制备ＹＡＧ－Ａｌ_２Ｏ_３纳米复合粉体具有成本低、产量高和工艺简单的优点．     

纳米与粉体材料

武汉工程大学纳米钛酸锶粉体技术问世；纳米高分子材料技术研究中心在温州大学挂牌；美国研制出高反射率纳米镜子；防玻璃起雾纳米涂层在美国问世；美国宇航局宣布：首次完成太空纳米感应器试验。     

残余氧化硼对钛酸锶钡晶胞参数及相变温度的影响

研究了氧化硼掺杂（B2O3）烧结钛酸锶钡（Ba1-xSrxTiO3，x=0、0．4、1）陶瓷钙钛矿结构的稳定性、晶胞参数以及相变温度．结果表明，随着掺杂量的增加，钛酸锶钡仍保持原来的钙钛矿结构，但晶胞参数有所变化．晶格常数c与a并非单调变化，但轴比c／a单调递减而晶胞体积a^2c却单调增大．和未掺杂钛酸锶钡相比，掺杂钛酸锶钡陶瓷的相变温度有所升高．同一掺杂含量下，随着烧结温度的升高，因钛酸锶与钛酸钡相互固溶引起晶胞体积明显收缩，相变温度逐渐降低．但在同一烧结温度下，随着掺杂量的增加，相变温度几乎不变．说明硼离子半径虽然很小，氧化硼对钛酸锶钡晶胞参数的影响还是存在的，而且只能以填隙方式存在于晶胞，但其固溶能力非常有限．     

SiC粉体表面性质及其浆料流变性质研究

研究了两种不同来源的SiC粉体的表面性质及其浆料的流变性质．发现尽管两种粉体的粒径分布相近,形貌相似,但由于粉体表面性质的差别导致两种粉体形成的浆料有不同的流变性质．其中SiC－1粉体需添加分散剂PEI形成稳定浆料,其最高固体含量为40vol％,而SiC－2仅依靠调节浆料的pH至10左右即可以获得固体含量高达55vol％的稳定浆料．     

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.