稀土铈掺杂对纳米TiO2结构和性能影响

研究了纳米二氧化钛负载稀土铈离子的基本性能,二氧化钛对铈离子的吸附机理,焙烧温度对二氧化钛晶型结构影响,不同吸附量对二氧化钛光学性能的影响;结果表明纳米级二氧化钛对铈离子具有很强的吸附力,铈离子的添加提高了二氧化钛晶型转变温度,铈离子的吸附可以提高二氧化钛的光催化降解性能。     

锌沸石-Ce/TiO2抗菌材料的制备及其性能研究

以纳米锐钛矿型TiO2粉体作为主要原料,锌沸石作为载体,铈离子为掺杂离子,采用浸渍法制备锌沸石-Ce/TiO2抗菌材料,运用抑菌圈法对其抗菌性能进行评价,用紫外光谱对比纯纳米TiO2抗菌材料和锌沸石-Ce/TiO2抗菌材料的光催化效果。结果表明,纳米TiO2与硝酸铈的物质的量比为40∶1、反应时间为0.5h、焙烧温度为300℃、pH=3条件下抗菌性能最佳,抑菌圈直径达到34.63mm。锌沸石-Ce/TiO2抗菌材料样品对于大肠杆菌具有明显的抑杀效果。     

高活性TiO2纳米晶的酸催化Sol-Gel法制备与表征

采用酸催化的溶胶-凝胶法制备出了纳米TiO2光催化剂，以甲基橙的光催化降解为探针反应，评价了其光催化活性．运用XRD、TEM、FT—IR以及PL光谱技术对纳米TiO2的微晶尺寸、晶体结构、表面组成和性能进行表征．结果表明，400℃焙烧的TiO2纳米粒子的颗粒形貌为近球形，晶粒尺寸为11．69 nm，样品分散性良好的锐钛矿型结构．在光催化降解甲基橙的实验中，400℃焙烧的TiO2纳米粒子表现出最高的光催化活性，这与表征结果一致．此外，550℃和650℃焙烧的具有锐钛矿型和金红石型混晶结构的TiO2纳米粒子，无混晶协同促进效应．     

掺杂镧和铈的TiO2纳米粒子的结构相变

以钛酸四丁酯,La2O3和Ce(NO3)3@6H2O为原料,采用溶胶-凝胶法制备了纯的和分别掺杂5mol%镧和铈的TiO2纳米粒子,并利用XRD,TG-DTA,TEM和XPS等测试技术对样品的晶型、尺寸和形貌等进行了表征,主要考察了镧和铈的掺杂对TiO2的晶粒尺寸和锐钛矿→金红石结构相变的影响,并初步的探讨了镧和铈的作用机理.结果表明,600℃焙烧而获得的TiO2纳米粒子具有与P-25型TiO2粒子相类似的组成、结构、形貌和粒子尺寸;掺杂剂镧和铈分别以La2O3和CeO2小团簇形式存在,并比较均匀的弥散在TiO2纳米粒子中,二者的掺杂抑制了锐钛矿晶粒的增长和锐钛矿→金红石的结构相变,使相变温度显著提高,晶格畸变增大,而镧比铈的作用更加显著.镧和铈的作用机理可能主要与掺杂离子的半径和价态以及稀土氧化物的存在和熔点等有关.     

TiO2离子筛的合成及锂吸附性能研究

以离子筛型氧化物为关键材料的锂离子选择性吸附技术是近年来盐湖卤水提锂的重要研究方向.采用商品TiO2经过研磨、焙烧浸锂、酸洗脱锂和干燥过程制备得到立方晶相尖晶石结构的TiO2离子筛,通过XRD和SEM对样品晶相结构和表面形貌进行了表征,探索了焙烧温度和Li/Ti比对离子筛前驱体结构的影响,进一步对Li+吸附性能进行了研究.结果表明,当Li/Ti摩尔比为0.9,TiO2和Li2CO3在1173K焙烧24h后得到了近乎为纯晶相的尖晶石结构Li4Ti5O12前驱体,经酸脱锂后得到对Li+具有记忆效应的TiO2离子筛,对Li+的平衡吸附量为2.530 mmol/g.     

钇或钕掺杂TiO_2纳米纤维的制备及光催化性能研究

采用静电纺丝技术,以Ti(SO4)2、聚乙烯吡咯烷酮(PVP,Mr=1300000)、稀土氧化物和N,N-二甲基甲酰胺(DMF)为原料,成功地制备了TiO2、Y/TiO2和Nd/TiO2纳米纤维.用XRD、FESEM、TEM和TG-DTA等分析手段对样品进行了表征.XRD分析结果表明,当焙烧温度为550℃时得到纯锐钛矿相RE/TiO2(RE=Y,Nd)纳米纤维,900℃时得到纯金红石型RE/TiO2(RE=Y,Nd)纳米纤维,稀土离子显著降低了TiO2的晶格参数.FESEM分析结果表明,RE/TiO2(RE=Y,Nd)纳米纤维直径约为50nm、长度300μm.以罗丹明B和苯酚为目标降解物,研究了三种催化剂的光催化性能.其中,1.5mol%Y/TiO2光催化剂对罗丹明B的降解效率较高,而1.0mol%Nd/TiO2对苯酚具有较好的降解活性.因此,掺杂不同稀土离子的TiO2纳米纤维对不同降解物的降解能力不同.     

凹凸棒石黏土负载纳米TiO_2的制备表征及对Ni(II)吸附研究

以溶胶-凝胶法制备法制备了凹凸棒石黏土负载纳米TiO2吸附剂,采用FT-IR、SEM、XRD等分析方法对凹凸棒石黏土负载纳米TiO2前后的结构进行了表征。并对Ni(II)进行了吸附机理和性能的研究。结果表明:经过高温焙烧后的凹凸棒石黏土负载纳米TiO2吸附剂较负载前的凹凸棒石黏土,因其结构中的结晶水和沸石水脱失,内部孔道面积和表面积增加,活性吸附位点的数量增大,吸附能力有了明显提高。在室温条件下(20~25℃),pH为6~7,吸附平衡时间为120min时,凹凸棒石黏土负载纳米TiO2吸附剂对Ni(II)有较好的吸附效果。     

羧甲基壳聚糖/Ce^3＋掺杂TiO2复合抗菌材料的研究

采用溶胶-凝胶法制备稀土（Ce^3＋）掺杂纳米TiO2（纳米Ce/TiO2）,借助XRD、BET、SEM对Ce/TiO2进行表征。结果表明纳米Ce/TiO2晶型为锐钛矿,平均晶粒大小为19.95nm,比表面积为43.302m^2/g。采用超声波催化法合成了羧甲基壳聚糖（CMC）,并与Ce/TiO2复配制得羧甲基壳聚糖/Ce3＋掺杂纳米TiO2复合材料（CMC/Ce/TiO2）,借助FT-IR对CMC及CMC/Ce/TiO2复合材料进行了结构表征。初步研究了纳米Ce/TiO2、普通纳米TiO2、CMC/Ce/TiO2、CMC的抗菌性能,结果显示纳米Ce/TiO2对大肠杆菌和金黄色葡萄球菌的抗菌率分别为55%和53%,普通纳米TiO2对两种菌的抗菌率分别为50%和45%,Ce^3＋的掺杂可提高纳米TiO2的抗菌性能;CMC/Ce/TiO2对大肠杆菌和金黄色葡萄球菌的抗菌率分别达到99%和95%,CMC对两种菌的抗菌率分别为90%和80%,Ce/TiO2的复合可显著提高CMC的抗菌性能。     

TiO2／（O′＋β′）-Sialon复相陶瓷的制备与表征

以纳米TiO2粉和（O′＋β′）-SiMon粉为原料、Yb2O3或Tb2O3为添加剂，在高纯N2气氛下采用常压烧结制备出了TiO2／（O′＋β′）-Sialon复相陶瓷。采用XRD对材料进行物相、晶粒度分析，采用SEM＆EPMA对材料进行形貌观察和元素面分布分析。结果表明，随烧结温度的升高和恒温时间的延长，TiO2逐渐由锐钛矿相向金红石相转化，同时晶粒也逐渐长大。Tb2O3和Yb2O3分别对锐钛矿相变有显著的抑制和促进作用，通过控制烧结制度、添加剂种类及含量可得到不同TiO2相组成的TiO2／（O′＋β′）-Sialon。Tb2O3和Yb2O3均对TiO2晶粒生长有抑制作用，在不高于800℃的温度下烧结可得到纳米TiO2／（O′＋β′）-Sialon复相陶瓷。     

碳掺杂TiO2纳米管列阵的制备及其光催化性能的研究

采用电化学阳极氧化法制备TiO2纳米管列阵,并在CO气氛中对TiO2纳米管样品进行焙烧.XPS研究表明,在CO中焙烧的样品产生了Ti-C峰,说明有C的掺杂.SEM及XRD衍射实验表明,随着焙烧温度的升高,C的掺杂加速了TiO2纳米管的晶型结构向金红石相的转变,管壁明显增厚.以亚甲基蓝为光催化实验降解对象,研究了C掺杂对TiO2纳米管的光催化性能的影响,发现在550℃下焙烧后的TiO2纳米管具有较好的光催化活性,C的掺杂能明显提高TiO2纳米管的光催化性能.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.