锑掺杂浓度对二氧化锡纳米微粉的影响

以无机盐为原料,采用共沉淀法制得了掺锑SnO₂纳米级微粉.运用X射线衍射(XRD)、透射电镜(TEM)和差热分析(DTA)等观测手段对微粉末进行了表征,比较系统地研究了掺锑浓度对物相、粉末颗粒度及电阻的影响规律.实验结果表明,低掺杂浓度样品(x≤0.462),Sb原子固溶于四方晶系SnO₂中,高掺杂浓度样品(x≥0.519),Sb原子将从固溶体中脱溶并被氧化为Sb₂O₄相;掺杂Sb可以减小SnO₂的晶粒度,在热处理时阻碍 SnO₂晶粒长大,掺杂浓度>0.181时,进一步掺杂对粉末粒度没有明显的影响;SnO₂粉末电导率随掺锑浓度的增大而提高,掺杂浓度为0.095时粉末电导率达到极大值,当掺杂浓度>0.245时,粉末电阻快速增大.兼顾掺杂浓度对粉末粒度和电阻的影响,合适的掺杂浓度x为0.181～0.230.     

锑掺杂量对ATO纳米颗粒结构及其导电性能的影响

以SnCl4.5H2O和SbCl3为主要原料,采用sol-gel法制备了锑掺杂二氧化锡（ATO）纳米粉体。分别利用FESEM、XRD、FT-IR、XPS及四探针电阻仪对粉体形貌、晶体结构、元素组成和粉末电阻进行表征,考察Sb掺杂量对ATO粒子晶体结构、晶粒尺寸和导电性能的影响。结果表明所制备的ATO为（110）面择优取向的四方相锡石结构的纳米颗粒,当Sb掺杂量为15%（摩尔分数）时,ATO具有最小的粉末电阻率（12.85Ω.cm）。当Sb掺杂量≤28%时可得到完全掺杂的ATO,ATO的导电性与其中的Sb5＋离子浓度有关,而且Sb含量在28%以下可能存在一个阈值,有利于固溶在SnO2晶格中的Sb形成Sb5＋,使载流子浓度达到最大,因而表现出最佳的导电性能。     

常压CVD法制备Sb掺杂SnO2薄膜的性能研究

以C4H4SnCl3和SbCl3为反应先驱体,采用常压化学气相沉积法制备Sb掺杂SnO2薄膜,研究了薄膜沉积时间、基板温度以及Sb掺杂量对薄膜结构和红外反射性能的影响。利用X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)等手段对所制备薄膜的结构、形貌、成分进行了分析表征。XRD结果表明薄膜具有四方相金红石晶型结构,在基板温度为650℃时能制得结晶性能较好的多晶薄膜;XPS结果表明元素Sb主要以Sb5+的形式掺杂于SnO2薄膜中。还讨论了Sb掺杂量对方块电阻、透射率等薄膜性质的影响。结果表明,当Sb掺杂量为2%,基板温度为600℃,镀膜时间为4min时可制备出可见光透过率为75%、红外透过率仅为30%的薄膜,且此时薄膜方块电阻为38.4Ω/□。     

络合法合成Sb掺杂SnO2(ATO)纳米粉体

采用非均相成核法，在晶种上以络合法均匀生长Sn，Sb混合金属氢氧化物，合成了纳米ATO导电粉体．以粉体电阻、粉体粒径为指标进行实验，得到了最佳络合剂．系统研究了合成条件如掺杂浓度，反应温度、pH值、配体／Sb比等对最终粉体导电性能的影响．以TG—DTA、XRD、TEM等手段研究了晶粒生长过程．结果表明粉体为四方金红石型结构，平均粒径为10nm左右，粉体的团聚很少．     

pH值在掺Ni纳米SnO2粉末制备中的作用

以SnCl4·5H2O、NiCl2·6H2O、氨水为主要原料,采用化学共沉淀法制备纯的及掺Ni的SnO2纳米粉体.针对重要的影响因素pH值运用原子吸收光谱、XRD、FT-IR等手段进行分析.XRD和FT-IR分析结果表明,pH在1.5～10之间均可合成SnO2;晶粒尺寸随着pH值的增大无显著改变.通过对掺Ni的Sn(OH)4胶体滤液中Ni元素的原子吸收光谱分析可知,pH值严重影响着杂质Ni的掺入量,Ni2 掺入率在pH=8时出现极大值为99.97%.     

氟掺杂SnO2纳米粉体的溶胶-凝胶法制备及表征

以SnCl2.2H2O和HF作为原料通过溶胶-凝胶法制备氟(F)掺杂SnO2(FTO)纳米粉体。采用XRD、TEM、电阻测定和XPS对制得的FTO粉体的结构、粒径、导电性能和组成等进行表征。研究结果表明:在pH为9,600℃煅烧2h和F/Sn掺杂比为0.4的条件下,FTO纳米粉体粒径约为18～45nm,为不规则的球形结构,粉体压片后的薄层电阻为16.34Ω/□。     

掺杂Sb对二氧化锡纳米粉末晶粒尺寸及电阻率的影响

以SnCl4·5H2O,SbCl3为前驱体,采用So1-Gel法制备了不同Sb掺杂量的SnO2纳米粉末.对粉体的电阻率、粒度分布、比表面积进行了测量,并用X射线,扫描电镜对粉体进行了表征.结果发现,随着Sb掺杂量的提高,ATO复合纳米粉末的晶粒度减小,Sb掺杂对粉末电阻率的影响存在一拐点,Sb掺杂量较少时,粉体的电阻率随Sb含量的提高而降低,在5%～7%中有一个最小值,此后,随着Sb含量的提高,电阻率开始升高.通过对粉体粒度计算和比表面等径分析,ATO纳米粉末存在团聚现象,解决团聚问题是今后进一步研究的方向之一.     

Sb掺杂Sn2S3薄膜的表征及电学特性

真空蒸发制备Sb掺杂Sn2S3多晶薄膜。研究不同比例Sb掺杂对Sn2S3薄膜的电学、结构、表面形貌、化学组分的影响,实验给出掺Sb5%薄膜经380℃热处理30 min可获得结构良好正交晶系的Sn2S3∶Sb多晶薄膜,薄膜的电阻率从未掺杂时的79kΩ.cm降到23.7Ω.cm,下降了三个数量级。Sn2S3薄膜表面为颗粒状,体内化学计量比Sn/S为1∶1.49,与标准计量比非常接近;掺Sb(5%)后为1∶0.543,Sn过量。Sn和S以Sn2+,Sn4+,S2-形式存在于薄膜中;Sb元素显示正5价,部分Sb5+进入晶格替位Sn4+。     

F—Sb共掺SnO2复合材料的制备及电解甲基橙性能

以KF、SbCl3和SnCl2为原料配制乙醇溶胶，通过在Ti基底上涂胶、干燥、预热处理和煅烧等工艺制备出了F—Sb-SnO2/Ti复合电极。以F—Sb—SnO2／Wi复合电极为阳极，镍片为阴极，施加恒电压观测甲基橙电解液的脱色变化，在正交设计试验基础上，考察溶胶涂层数、煅烧温度、掺杂F离子的浓度等因素对甲基橙降解率的影响，结果表明，固定电解参数电压3V，甲基橙浓度50mg／L，添加荆h（Ⅲ）浓度110mg/L，溶液pH=l，优化的溶胶涂层数9，煅烧温度为773K，溶胶中维持Sn/Sb摩尔比9／1时，优化的KF掺杂摩尔比为0．5时，电解75min，甲基橙的降解率达93％。     

导电CaSO_4晶须制备工艺优化及其应用

采用正交试验法对导电CaSO4晶须的制备工艺进行了优化。通过改变掺杂比(Sb/Sn)、反应温度、反应pH值等3大因素,结合反应产物的测试表征,得到了试验范围内最优的合成条件。实验范围内的最佳制备方案:掺杂比(Sb/Sn)5%,反应温度60℃,pH=1,导电CaSO4晶须的体积电阻率值达到0.199kΩ·cm,白度70。将最佳合成条件下的导电CaSO4晶须掺杂在PAN的DMF溶液中进行湿法纺丝,获得了白色导电PAN纤维。     

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.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

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.