微孔聚酰亚胺球轴承保持器材料的研究

微孔聚酰亚胺材料用作球轴承保持器已在航空工业界引起重视。这种新材料最重要的特征在于其微孔性织态结构。它具有较好的含油能力,使运动中的轴承始终处于良好的润滑条件下。 本文报道用双马来酰亚胺共聚物制备轴承保持器的研究工作,并讨论包括分级、混合在内的制粉工艺和坯料的制备工艺对保持器总孔容和孔隙度分布的影响。     

热致相分离法制备共聚物微孔膜研究进展

阐述了热致相分离法(TIPS)制备微孔膜的研究现状。介绍了混合共聚物膜及共聚物微孔材料的制备条件及其性能,包括等规聚丙烯/聚丁烯、聚偏氟乙烯/聚甲基丙烯酸甲酯、乙烯/三氟氯乙烯共聚物、乙烯/丙烯酸、乙烯/乙烯醇和乙烯/乙烯醇/乙烯缩丁醛等,并对TIPS方法制备共聚物微孔膜的研究方向进行展望。     

聚丙烯微孔发泡材料泡孔结构控制的研究进展

聚丙烯微孔发泡材料具有较好的性能和较高的比强度,泡孔结构是影响聚丙烯微孔发泡材料性能的关键因素,其主要由聚丙烯基体性质、共混改性、添加纳米粒子、控制工艺条件等因素控制。从这些影响因素出发,综述了近年来聚丙烯微孔发泡材料泡孔结构控制的研究进展,并展望了其应用前景。     

橡胶-塑料微孔材料的性能研究

对橡胶与聚乙烯共混微孔材料进行了静态力学和动态力学性能表征，并通过电镜观察其材料拉伸受力前后的微孔结构变化，了解材料的各种力学行为及材料组份和加工工艺对材料力学性能的影响，同时检验材料的透水性能。     

微孔发泡高分子材料

微孔发泡材料是新型的改性热塑性高分子材料，微孔的引入提高了坑分子材料的韧性，绝缘性，耐热性和耐疲劳性能等。文中以美国麻省理工学院Suh教授等研制开发的微孔发泡材料为主线，综述了微孔发泡高分子材料的研究背景，发展历史，性能特征，泡孔成核模型公式，制备以及应用前景，以推动我国的研究在该领域的发展。     

微孔材料的研究进展

微孔材料因其特有的微观结构而具有特殊的性能,在很多领域都有应用或应用前景.综述了微孔材料的特殊性能和其在多领域的应用,以及微孔分子筛、微孔膜、微孔泡沫、微孔陶瓷、微孔淀粉泡沫等常见微孔材料的性能和制备方法,并介绍了微孔材料的常见分类方法.     

新型蓝色有机发光材料苯-吡啶共聚物的光电性能

报道了4种新型有机发光材料苯－吡啶共聚物在室温下的光吸收、光致发光特性和能带结构特点。用4种材料共聚物设计了单层发光元件，并在液氮中（77K）测定了其发光性能。4种材料均得到了蓝色发光。     

N—苯基马来酰亚胺／苯乙烯／丙烯腈乳液共聚物的力学性能研究

本文对由乳液聚合得到的Ｎ－苯基马来酰亚胺／苯乙烯／丙烯腈三元共聚物热塑性塑料的力学性能进行了研究，结果表明，不仅各组份的用量对材料的冲击强度，硬度，弯曲强度有明显的影响，而且聚合工艺对材料力学性能也有显著的影响，采用一定的组成，选用合适的聚合工艺得到组成较为均一的共聚物是提高材料性能的关键。     

微孔聚合物皮层厚度测量的扫描声显微方法

微孔发泡是一种有广泛应用前景的聚合物改性方法。皮层的存在对微孔结构材料的性能有很大的影响,皮层厚度的测量、工艺控制和理论计算是微孔材料加工中的主要问题。文章介绍了一种测量微孔聚合物皮层厚度的新的有效方法——扫描声显微(SAM)方法,并测量了微孔聚苯乙烯和微孔聚碳酸酯的皮层厚度。     

聚酯-聚醚-聚硅三元嵌段共聚物的制备及亲水性能研究

采用酯交换-缩合聚合工艺,以对苯二甲酸二甲酯(DMT),乙二醇(EG)以及通过硅氢加成工艺制备的聚醚-聚硅嵌段共聚物为单体,合成聚酯-聚醚-聚硅三元嵌段共聚物亲水材料。采用IR、1 H-NMR、TGA、SEM,接触角测试研究了聚酯-聚醚-聚硅三元嵌段共聚物的组成、结构与润湿性能的关系。研究表明聚酯-聚醚-聚硅三元嵌段共聚物材料具有良好的亲水性能,而且随着聚酯含量的增加,亲水基团增多,亲水性能明显改善。     

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...     

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.     

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.     

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

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.