碳纤维增强铜基复合材料制备方法研究进展

综述了碳纤维增强铜基复合材料的主要制备方法及其发展现状,重点讨论了粉末冶金法、热压扩散烧结法、熔渗法、PVD法、CVD法及电镀法等常用制备工艺的原理及特性,分析了不同制备方法的优缺点及适用领域,提出了现有方法中存在的问题,并展望了碳纤维增强铜基复合材料的发展趋势及在输变电领域的应用前景。     

石墨烯的化学气相沉积法制备

化学气相沉积(CVD)法是近年来发展起来的制备石墨烯的新方法,具有产物质量高、生长面积大等优点,逐渐成为制备高质量石墨烯的主要方法.通过简要分析石墨烯的几种主要制备方法(胶带剥离法、化学剥离法、SiC外延生长法和CVD方法)的原理和特点,重点从结构控制、质量提高以及大面积生长等方面评述了CVD法制备石墨烯及其转移技术的研究进展,并展望了未来CVD法制备石墨烯的可能发展方向,如大面积单晶石墨烯、石墨烯带和石墨烯宏观体的制备与无损转移等.     

Cu和Pd在TiN表面的置换析出行为及其热力学分析

由于开发了防止Cu和Si系材料相互扩散的阻隔材料,用铜做配线的大规模集成电路逐渐得到广泛的应用.电镀法形成微细铜配线的工艺是在基板上形成扩散阻隔层后,再用CVD或PVD法镀以铜层(称为种层),以此为阴极,其上电析铜配线.     

化学气相沉积法制备钨芯SiC纤维的装置和工艺

分析比较了两种不同类型化学气相沉积(CVD)法制备钨芯SiC纤维的反应器,提出了改进方法,设计了一种立式冷壁反应器,并对用CVD法制备钨芯SiC纤维的工艺进行了研究.运用扫描电镜观察了制备纤维形貌,并用Weibull统计方法分析了纤维强度与其形貌之间的关系.结果表明,在不同的氢气流量和氮气流量比下,沉积速率均随沉积温度的升高而增大.总反应在较低温度区受表面反应控制,在较高温度区受质量传输控制.纤维的断裂强度大致可分为高、中、低3个区,CVD-SiC纤维的强度与其微观形貌有密切关系,缺陷的多少决定纤维强度的高低.     

化学气相沉积技术在锂离子电池电极材料中的应用

化学气相沉积(CVD)是近年来发展起来的制备各种无机复合材料的一种新技术.简要介绍了CVD技术的原理和特点,分析了目前研究的各种锂离子电池正负极材料存在的问题,重点介绍了CVD技术在解决这些问题上的应用进展.     

大面积光学级金刚石自支撑膜制备、加工及应用

大面积光学级金刚石自支撑膜的制备和加工是近年来在CVD金刚石研究领域的最重要的技术进展之一.在军事和民用光学领域有非常重要的应用前景.本文综述了北京科技大学近年来在CVD金刚石膜光学应用领域的研究进展.给出了采用高功率直流电弧等离子体喷射(DC Arc Plasma Jet)CVD工艺制备大面积光学级金刚石自支撑膜的研究结果,并报导了对所制备的光学级金刚石自支撑膜的光学、力学(机械)、热学、微波介电性能和抗激光损伤等方面的最新研究结果.     

CVD法制备石墨烯中碳源材料的研究进展

大尺寸和晶体结构完整的单层和多层石墨烯的高效制备方法对其工业化生产和大范围应用具有重要意义。化学气相沉积法(CVD)是合成高质量石墨烯薄膜的最有前途的方法。综述了通过常规CVD法或改良CVD法,如等离子体增强CVD法(PE-CVD),制备单层或多层石墨烯所用的固体(S)、液体(L)和气体(G)碳源的先进研究活动和最新进展。     

中科院化学所在石墨烯可控制备和性能研究方面取得系列进展

在中国科学院、科技部、国家自然科学基金委和化学所的大力支持下,中科院化学所有机固体院重点实验室相关研究人员在石墨烯的可控制备和性能研究方面取得系列进展,相关结果发表在PNAS、JACS(2篇)、Adv.Mater.(3篇),并应邀在Acc.Chem.Res.杂志上发表了述评。液态铜上生长石墨烯。在众多的石墨烯制备方法中,化学气相沉积法(CVD)由于成本低、可控性好、可大规模制备等优点近年来掀起了对其的研究热潮。2009年,美国奥斯汀大学Ruoff组利用固体铜箔作为金属催化剂制备出了连续     

化学气相沉积法制备氮化硼纳米管的研究进展:反应装置、气源材料、催化剂

氮化硼纳米管(BNNTs)具有优良的耐高温、抗氧化、防辐射、绝缘和导热性能,因此,在航空航天、辐射屏蔽、热界面材料以及深紫外发射等领域具有潜在的应用前景。然而,高品质BNNTs的可控制备和批量生产仍然是学术和工业界的重大挑战。在BNNTs的众多制备方法中,化学气相沉积法(CVD)是最有潜力实现其可控制备的方法之一。但是,科学家们对于CVD法制备BNNTs的催化机理和影响因素尚未形成共识。鉴于此,文章从反应装置、氮源、硼源和催化剂4个方面对CVD法制备BNNTs进行了综述,并系统总结了相应的规律。在此基础上,分析了目前BNNTs可控制备中存在的问题,并对CVD法在BNNTs可控制备中的作用进行了展望,以期对今后BNNTs的制备起到借鉴作用。     

碳纳米管MPCVD和TCVD制备的比较分析

碳纳米管主要的制备方法是化学气相沉积法(CVD).采用CVD法中最主要的微波等离子体化学气相沉积法(MPCVD)和热化学气相沉积法(TCVD)制备出定向的碳纳米管.并从制备工艺,场发射性能和SEM结构等方面对两种方法进行比较分析,得出对碳纳米管制备有一定指引和借鉴意义的结论.     

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...     

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.……     

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.     

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.     

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.     

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.     

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