二维层状磁性镁铝水滑石的制备与表征

采用共沉淀法将磁性基质与镁铝水滑石组装制备二维层状磁性镁铝水滑石,考察了在一定的pH值、沉淀生成温度及陈化时间下,不同n(Mg2 )/n(Al3 ),n(Fe2 )/n(Mg2 )比值及焙烧温度对合成磁性镁铝水滑石结构的影响,并借助HRTEM、XRD、VSM、TG-DSC、FT-IR等手段对其晶型结构、磁学性能及结晶度等进行表征,结果表明镁铝水滑石在赋予磁性后,并没有改变其典型的层状结构,证实了将磁性基质与层状材料组装合成的可行性.     

纳米晶镁铝水滑石制备机理及抗毒性研究

以尿素为沉淀剂制备纳米晶镁铝水滑石,考察不同镁铝比制备的纳米晶镁铝水滑石催化剂对大豆油酯交换的影响以及催化剂的抗水抗酸性和使用寿命,并探讨纳米晶镁铝水滑石的合成机理.随镁铝摩尔比增加,酯交换反应所需时间减少,当m(Mg2 ):m(Al3 )=3:1时,转化率高达94.2%;当m(Mg2 ):m(Al3 )=4:1时,使用寿命最长,可重复使用5次.纳米晶镁铝水滑石具有较强抗水抗酸性,故在进行酯交换反应中无须脱水脱酸.     

水滑石除磷的吸附动力学研究

采用共沉淀法制备了Mg/Al水滑石,研究了不同Mg/Al物质的量比、材料用量、不同pH条件下Mg/Al水滑石吸附除磷的动力学特征,从而对吸附速率的控制过程进行分析。结果表明水滑石对磷的吸附能较好地符合准二级动力学方程、Elovich动力学方程和内扩散模型。n(Mg)/n(Al)=3是水滑石最理想配比,水滑石投加量越大,外扩散过程越慢;一定范围内pH的升高能促进水滑石对磷吸附速率和吸附容量的提升。     

纳米晶镁铝水滑石结晶动力学

以尿素为沉淀剂制备纳米晶镁铝水滑石,其结晶生长机理与粒径无关.从相变驱动力、晶种与晶体形成、成核速率和晶体生长速率3个方面研究了纳米晶镁铝水滑石的结晶动力学,求出不同温度下成核速率、晶体生长速率及其相应的表观活化能,并确定其动力学模型.结果表明影响晶粒形成和生长的主要因素是晶化温度和反应物过饱和度.当x(Mg):x(Al)=3、晶化温度120℃、晶种Al(OH)3、晶种用量3.0%时可快速得到较好的层状纳米晶镁铝水滑石.     

纳米晶Mg-Al水滑石的水热合成及合成机理

讨论了不同的Mg、Al源为起始反应物、反应温度、时间和碱度对水热合成Mg-Al水滑石物相组成和晶粒度的影响. 用XRD、SEM对合成产物进行了表征, 用X射线全谱拟合法计算了Mg-Al水滑石晶粒度. 以MgO和Al(OH)₃为起始反应物, Mg/Al=2,在140℃反应4～10h, 可以制备出高结晶度的单相纳米晶Mg-Al水滑石. Mg-Al水滑石的形成机理可概括为: 水解反应-沉淀成核-晶粒长大. 反应物类型及合成条件会影响前驱物的水解速率和水解程度, 进而影响晶体成核和生长速率,控制物相的组成和晶粒度大小.     

硝酸根插层钴铝类水滑石的一步原位合成与表征

选用硝酸钴、硝酸铝、六次甲基四胺(HMT)为原料,采用HMT水热分解法,选定适宜的n(Co2+)/n(Al3+),调控n(NO3-)/n(HMT)实现了硝酸根插层钴铝类水滑石的一步原位合成。利用X射线衍射分析(XRD)、红外(FT-IR)、比表面积测定(BET)、扫描电镜(SEM)、粒径分析等方法对制备过程所得物相进行检测与分析。结果表明,硝酸根插层钴铝类水滑石的一步原位合成是基于勃姆石(Al OOH)物相转化形成的,而合成体系p H值及合适的n(Co2+)/n(Al3+)则是能否形成结构完整、晶相单一、结晶度良好的硝酸根插层钴铝类水滑石的关键。     

温和条件下硝酸根型ZnAl-LDHs的合成与表征

以硝酸锌、硝酸铝、硝酸钠和氢氧化钠为原料,用共沉淀法制备了不同配比下的锌铝层状双金属氢氧化物(ZnAl-LDHs).探讨了组分配比、合成方式、老化时间等对ZnAl-LDHs合成的影响.通过XRD、SEM、IR分析表征了合成的化合物.结果表明:与MgAl-LDH需要在碱性条件下合成的认识不同,ZnAl- LDHs可以在温和pH条件下(且不能在碱性条件下)合成.随着Zn/Al比的增加,合成的ZnAl-LDHs层间距增大,晶形越完整.当n(Zn)/n(Al)=2∶1,pH=6,老化时间为24 h,晶化温度为70℃时,合成的ZnAl-LDHs结晶度好、纯度高.     

不同形貌高炉渣基沸石的合成及反应机理的探讨

高炉渣是高炉炼铁过程中的副产品,是一种复杂的硅酸盐,高炉渣酸浸后的滤渣是硅凝胶,可以作为硅源,从而合成沸石。以高炉渣为前驱体,采用碱熔融-水热法合成不同形貌沸石,通过X射线衍射分析、扫描电子显微镜等表征手段探讨了最佳合成条件及反应机理。结果表明,体系中硅铝比为影响沸石结构种类的关键因素,n(Si)/n(Al)=0.4～1.2范围内,能够合成A型沸石;n(Si)/n(Al)=1.6～2.0范围内,能够合成八面沸石;n(Si)/n(Al)=1.4处为A型与八面沸石共存体系;八面沸石的形成需经过溶解—成核—结晶等几个过程,属于双相转化反应机理;合理控制晶化温度可将八面沸石转变为P型沸石。     

CuMgAl类水滑石的合成、表征及催化性能研究

采用共沉淀法制备了不同配比的CuMgAl类水滑石化合物,通过XRD、IR、DTA分析表征了合成的化合物,并以其为前驱体经煅烧得到的CuO-MgO-Al2O3复合氧化物催化剂,在丙酮气相加氢一步合成MIBK反应中测试了其催化活性.结果表明:随着M2 /M3 比的增加,合成的类水滑石晶型越完整,层间距也随之加大,热稳定性降低;类水滑石中Cu2 含量的增加亦导致层板间距加大,热稳定性也随之降低;催化活性测试结果表明,在催化剂中Cu:Mg:Al=4:16:10时MIBK的选择性最佳,达38.61%.     

焙烧还原法合成纳米Mg3Al-EDTA-HTLcs水滑石

以Mg3Al-CO3-HTLcs水滑石煅烧产物为前驱体,采用焙烧还原法,辅助微波手段合成了纳米Mg3Al-EDT-HTLcs.研究表明,所合成的纳米Mg3Al-EDTA-HTLcs粒径为20～80nm,分散性较好,颗粒团聚少;反应温度为50～100℃、反应时间为0.5～6h、微波晶化时间为5～45min,均能合成出结晶良好、晶相单一的Mg3Al-EDTA-HTLcs.采用该方法均能快速合成出结晶良好的Mg3Al-EDTA-HTLcs.     

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.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

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.