WC对Cu/WC_P复合材料性能及组织的影响

通过ＷＣ含量对ＷＣ／Ｃｕ复合材料性能的影响，确定了冷压－烧结法制备Ｃｕ／ＷＣ材料的适宜ＷＣ含量为１０ｖｏｌ％左右。并就ＷＣ对该材料组织和再结晶行为的影响进行了有益的探讨。     

Preparation of polyimide-epoxy composites

The formation of a three dimensional network of crosslinked epoxy leads all unmodified epoxies to have inherent brittleness and relatively low degradation temperatures. Polyimides, on the other hand, are widely used for applications that require high degrees of flexibility and thermal resistance. Here, we have focused on the preparation of epoxy systems cured with polyamic acids instead of traditional amino-group-containing hardening agents. The cure behavior and potential reaction mechanisms of EPON 828 resin and polyamic acid mixtures were evaluated by DSC and TGA. Thermal analysis showed a complex reaction sequence taking place in the mixture and also determined the extent of reaction of the polyamic acid with itself and the competitive reaction of the polyamic acid with the epoxy. The compositions of the mixtures were varied to see the dependence of the cure behavior on component concentrations. Solutions of the two components did not phase separate and also phase separation was not apparent either optically or microscopically in the cured samples. This phase behavior was attributed to a unique in situ reaction. A novel solvent system for the polyamic acid precursor was also used.     

反应堆材料热物性数据库管理系统

衡量一个数据库的质量，不以要看其所包含的数据还应考虑数据库管理系统的使用功能。为了更有效地实施ＩＡＥＡ的ＣＲＰ（ＣｏｏｒｄｉｎａｔｅｄＲｅｓｅａｒｃｈＰｒｏｇｒａｍｍｅ）中有关建立反应堆材料热物性数据库的计划，并考虑到能使所收集的数据方便地为用户服务和进行广泛的国际交流，为此设计并编制了该数据库的软件管理系统ＴＰＳＹＳ。这个系统可在ＩＢＭ－ＰＣ（３８６，４８６）等兼容机上运行，采用人机对话、菜单提示、全屏幕操作。其主要功能有：数据库维护、数据检索、与大型计算程序ＭＡＴ－ＰＲＯ接口和与国际上现有的数据库ＴＨＥＲＳＹＳＴ接口。     

Mechanical degradation of coating systems in high temperature cyclic oxidation

Cyclic oxidation tests were performed on a large variety of commercially available overlay coatings. The results of cyclic oxidation tests confirmed that the composition of the coating as well as the processing method of the coating can affect the life of the system. Coating life was determined by the time to coating penetration and initiation of substrate attack. As this work was part of a effort to evaluate the relative protectiveness of available coating systems for Industrial Gas Turbine applications at relatively high temperature, an extensive testing programme was undertaken. The different coatings were tested to visual failure. The results presented in this paper concentrate on the surface instability of the coating. Apart from usual oxidation of the coating an additional degradation mechanism was observed. A mechanical effect caused by the instability of the coating as a result of the difference in the thermal coefficient of expansion and mechanical properties between the substrate and coating. This effect, the so-called “rumpling” effect, resulted in a significant reduction in time to penetration and was in some systems the life controlling factor.     

Structural properties of inorganic materials: tungsten bronze SBN ceramics

Rare-earth doped strontium barium niobates were synthesized using usual ceramic technique. The dopants are La, Ce, Gd, Sm and Nd. The materials were characterized by XRD and density measurements. The grain sizes were determined from SEM analysis. Lattice parameters changed uniformly with rare-earth dopants in unfilled structures. Density measurements and SEM analysis confirmed only minute changes in the densities of the ceramics.     

Sensitizing Mechanism and Adsorption Properties of Dye—Sensitized TiO2 Thin Films

The dye-sensitized TiO2 complex films were prepared by the dye coat onto TiO2 surfaces,and the sensitizing mechanism and adsorption properties of the dye-sensitized TiO2 complex films were inverstigated.The influence of the application conditions of dye adsorbed on TiO2 films on the amount of dye adsorption was discussed.Experimental results show that the concentration,the temperature of dye solutions and the dipping time of TiO2 films in the dye solutions have a significant influence on the amount of dye adsorption.Cell test indicates that the conversion efficiency of light to electricity increases with the amount of dye adsorption.     

液相添加剂对PTCR陶瓷电性能的影响

液相添加剂ＡＳＴ（Ａｌ２Ｏ３＋ＳｉＯ２＋ＴｉＯ２）对ＢａＴｉＯ３陶瓷材料电性能的影响很大，随着Ａｌ２Ｏ３含量的增加，材料的电性能降低；ＳｉＯ２、ＴｉＯ２的物理特性对材料电性能影响较大；过量ＴｉＯ２对材料ＰＴＣ效应有重要影响，适当过量ＴｉＯ２含量，可得到性能优良的ＰＴＣＲ陶瓷。     

氮化硅的性能及其聚合物材料

叙述了氮化硅（Ｓｉ３Ｎ４）的性能并制备了含Ｓｉ３Ｎ４的聚合物材料，这种材料在医学上具有重要价值，对改变医学方面的概念、和对促进人类健康长寿具有重要意义。     

The effect of structural features on mechanical properties of loose optical fiber poly(butylene terephthalate) tubes

Results of a study on the modifying mechanical properties of loose optical‐fiber poly(butylene terephthalate) (PBT) tubes, produced during the standard industrial extrusion process, show that heat treatment make the structure of their material to change. The study comprised measurements of mechanical strengths properties of the tubes (tensile strength, compression strength, kinking) and determination of tube material structure [by differential thermal analysis (DTA), wide angle X‐ray scattering analysis (WAXD), and scanning electron microscopy (SEM)]. Results of the study allowed observation that the annealing at 70°C for 34 h of the tubes caused the crystalline α phase to increase in the tube material from ～28.5% to ～31.5% and the structure of the existing crystallites to become more perfect. This made the values of certain mechanical properties of the tubes to increase even by as much as 30%. The tubes following such thermal treatment could be used in cables exposed to heavy‐duty operation in arduous environments, where a larger margin from the standpoint of mechanical properties is required. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2130–2134, 2002