碳基/羰基铁复合吸波材料的研究进展

碳基/羰基铁复合吸波材料结合了各自优势,具有独特的物理化学特性和良好的吸波性能,成为近年来研究热点之一。本文结合国内外最新研究成果,介绍了羰基铁吸波剂自身改性的研究现状,将碳基/羰基铁复合吸波材料的研究成果系统归纳为6大类,即石墨烯/羰基铁复合吸波材料、碳纳米管/羰基铁复合吸波材料、碳纤维/羰基铁复合吸波材料、炭黑/羰基铁复合吸波材料、石墨/羰基铁复合吸波材料以及其他碳材料与羰基铁的复合吸波材料,并进行了详细介绍。最后,指出了碳基/羰基铁复合吸波材料未来研究亟待解决的性能调控和轻量化等问题,展望了其在宽频隐身等方面的发展前景。     

石墨烯基复合超级电容器材料研究进展

石墨烯基复合材料因其优异的性能广泛应用于各个领域,尤其在超级电容器的研究中。本文对石墨烯基复合超级电容器材料的结构进行了分类,并分别从石墨烯-碳基复合材料、石墨烯-导电高分子复合材料、石墨烯-过渡金属化合物复合材料的角度,总结了不同石墨烯基复合超级电容器材料的研究进展,重点强调了优化电极结构和提高电极性能之间的关系。同时,概述了石墨烯基复合材料在锂离子电池、太阳能电池、催化等其他方面的应用。获得高能量密度、功率密度以及长循环寿命的超级电容器是其作为电极材料的发展趋势。     

石墨烯基超级电容器电极材料研究进展

石墨烯基纳米复合材料是制备超级电容器电极的重要原料之一,也是当下的研究热点。首先介绍了石墨烯/导电聚合物、石墨烯/金属氧化物两类二元纳米复合材料的特点及其制备方法;再介绍了三种不同结构类型的石墨烯/导电聚合物/金属氧化物三元纳米复合材料,并通过分析其结构特点,说明其优势与不足;最后简要介绍了石墨烯与金属硫化物、贵金属粒子以及其他碳材料复合的研究现状。通过分析可知,目前石墨烯基纳米复合材料仍存在较多不足之处,寻求快速、绿色、经济的方法制备能有效提高超级电容器电化学性能的石墨烯基纳米复合材料,将是未来的发展方向。     

石墨烯基复合材料的研究进展

主要概述了石墨烯基功能性复合材料的研究进展,着重介绍石墨烯与聚合物、其他碳质材料、金属纳米粒子以及金属化合物纳米粒子组成的石墨烯基复合材料的研究进展及其应用前景。     

基于石墨烯的电磁波损耗材料研究进展

随着军事装备隐身伪装需求的迅速增长, 石墨烯基电磁波损耗材料成为科学研究的热点。本文总结了石墨烯基电磁波损耗材料的研究进展, 详细介绍了石墨烯与其它碳系材料、金属纳米材料、铁氧体材料、导电高聚物材料及非金属材料复合而成的二元、三元及以上多元石墨烯基电磁波损耗材料。简要阐述了电磁波损耗机理, 着重讨论了石墨烯基电磁波损耗材料的微观结构、组分数量及不同损耗机制对吸波性能的影响, 展望了石墨烯基电磁波损耗材料的研究重点和发展方向。     

石墨烯基吸附剂的特性、吸附原理、改性复合及 研究方法

石墨烯具有独特的结构和优异性能,适合用作水处理吸附材料。介绍了与吸附相关的石墨烯的结构及特性,石墨烯基材料对不同污染物的吸附原理;基于石墨烯的性质和结构特点,对石墨烯基材料的改性、复合方法及其研究方法作了较详细论述。鉴于石墨烯基材料再生性能的重要性,对磁性石墨烯及三维石墨烯吸附材料作了简单介绍,最后对石墨烯基吸附剂研究的发展方向作了展望。     

石墨烯基多孔碳材料对CO_2的捕集分离研究进展

日益严重的温室效应引起人们对CO_2捕集分离技术的关注。石墨烯基多孔碳材料以其优异的导热性、热稳定性、多孔性和高机械强度等优点,在CO_2捕集分离等方面展现出广阔的应用前景。对石墨烯基多孔碳材料在CO_2捕集分离方面的研究进展进行了综述,分析了二维石墨烯、三维石墨烯以及石墨烯复合多孔材料在CO_2捕集分离的研究进展。总结了提高石墨烯基多孔材料性能的方法,简述了石墨烯基多孔材料在CO_2捕集分离中的不足以及未来的研究方向。     

ZnO基复合材料的制备及光催化应用研究新进展

介绍了氧化锌(ZnO)基纳米复合材料的制备,包括ZnO与贵金属、石墨烯以及其他半导体材料的复合,调研了ZnO基不同复合纳米材料的光、电以及气敏等特性,综述了ZnO基纳米复合材料光催化性能研究的最新进展,并提出了展望。     

石墨烯基吸波复合材料的研究新进展

传统吸波材料因密度大、吸收强度弱以及吸收频带窄问题限制其应用发展。石墨烯作为碳家族的同素异形体,其零带隙结构使之具备优异的电性能。因此作为介电损耗型吸波机制的石墨烯与磁损耗型材料进行复合,通过两者的协同作用实现吸波体吸波性能的提升,进而满足当前吸波材料"轻、薄、宽、强"的性能要求。介绍了石墨烯基吸波复合材料的制备、吸波机理和吸波性能,并对未来石墨烯基吸波复合材料的发展前景进行了展望。     

基于氧化石墨烯与豆渣的复合碳材料制备及性能表征

以氧化石墨烯(graphene oxide,GO)和豆渣为原料,通过溶剂热反应获得了石墨烯基三维网状复合碳材料,并进一步通过高温焙烧获得导电性良好的复合碳材料。通过场发射电子显微镜、X射线衍射仪、拉曼光谱仪、元素分析仪、电化学分析仪对复合碳材料的形貌、物相、分子结构、元素组成和电化学性能进行了表征。结果表明,在GO中引入豆渣不仅可以在溶剂热和碳化过程中阻止石墨烯片层的重叠,还可以引入氮元素,该复合碳材料与纯GO或纯豆渣制备得到的碳材料相比表现出了更加优异的电化学性能。其中当GO与豆渣质量比为1∶2时,所得到的复合碳材料在1A/g的电流密度下比电容为201.9F/g,远高于纯石墨烯或纯豆渣所制备得到的碳材料比电容(分别为93和78F/g)。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

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.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

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.