Effects of oxide additives on sheet resistance of W thick-film conductor

A multilayer AIN-W cofired body has been developed using the pressless sintering technique. Effects of additives, such as Y₂O₃, CaO, La₂O₃, MgO, Al₂O₃ and SiO₂, on the sheet resistance of W conductor were studied. The sheet resistance of the W conductor increases with increasing additives in the W paste. However, the oxides can be divided into two groups. The effect of the first group on sheet resistance is different from that of the second group.     

碳纳米管承载氧化锆纳米粒子的研究

在液相沉淀法制备超细粉的工艺中引入碳纳米管，作为ZrO2的承载体。TEM观察发现添加表面活性剂可以实现碳纳米管对ZrO2的有效承载，未加表面活性剂出现了两者的分离。液相中Zeta电位分布的变化表明表面活性剂的添加有利于碳纳米管在水相中的分散，对工艺机理的研究揭示了表面活性剂其疏水基吸附在碳纳米管表面，而其亲水基与ZrO2水合物结合，在碳纳米管承载氧化锆纳米粒子复合材料制备中起到了桥接作用。     

Porous TiC Ceramics Derived from Wood Template

A porous TiC ceramic with a woodlike structure was prepared from wood template through tetrabutyl titanate vacuum-infiltration. The tetrabutyl titanate was first decomposed to TiO₂, and then in-situ reaction between TiO₂ and carbon template took place in the cellular wall at high sintering temperature. The original structure of wood was retained. In addition, the dimensional shrinkage of the pores after the removal of the residual carbon was different according to the difference of the wood density.     

Effects of the reinforcement and toughening of acrylate resin/CaCO3 nanoparticles on rigid poly(vinyl chloride)

Novel composite particles based on nanoscale calcium carbonate (nano‐CaCO₃) as the core and polyacrylates as the shell were first synthesized by in situ encapsulating emulsion polymerization in the presence of the fresh slush pulp of calcium carbonate (CaCO₃) nanoparticles. Subsequently, these modified nanoparticles were compounded with rigid poly(vinyl chloride) (RPVC) to prepare RPVC/CaCO₃ nanocomposites. At the same time, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were investigated, and the synergistic effect of modified nanoparticles with chlorinated polyethylene (CPE) was also studied. The results showed that in the presence of nano‐CaCO₃ particles, the in situ emulsion polymerization of acrylates was carried out smoothly, and polyacrylates successfully encapsulated on the surface of nano‐CaCO₃ to prepare the modified nanoparticles, breaking down nano‐CaCO₃ particle agglomerates, improving their dispersion in the matrix, and also increasing the particle–matrix interfacial adhesion. Thus, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were very significant, and the cooperative effect of the nanoparticles with CPE occurred in the united modification system. Scanning electron microscopy analyses indicated that large‐fiber drawing and network morphologies coexisted in the system of joint modification of nanoparticles with CPE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3940–3949, 2007     

热处理对两种铜膜结合强度的影响

采用PVD和CVD技术制备Cu/TiN/PI试样，研究表明，TiN薄膜可以有效地阻挡Cu向PI基板内部扩散，CVD工艺制备的Cu膜内部残余应力很小，Cu膜有相对高的结合强度；而PVD制备的Cu膜，在有TiN阻挡层存在的情况下，Cu膜内存在拉应力，拉应力降低了Cu膜结合强度，300℃退火可以消除膜内残余应力，结合强度提高。     

A study of function mechanism of hemxamethyl tetra-amine in gelation process of uranium

The UO2 ceramic microspheres are the most important materials in the spherical fuel elements for high temperature reactor (HTR). A process for preparation of UO2 kernels known as total gelation process of uranium (TGU) was developed as the production process of 10 mW HTR at Tsinghua University. The TGU process is based on the traditional sol-gel process, external gelation process and internal gelation process of uranium (EGU and IGU), which implies that the gelation action is initiated both by ammonia out of the gel particles and hemxamethyl tetra-amine (HMTA) inside the gel particles. The gelation behavior and the properties of uranium microspheres were investigated of the solution with and without HMTA. It is observed that good spherical particles can be obtained without HMTA in the sol, which indicates a more controllable and industrialized route will be set up. Contrasts between this route and the traditional EGU were also listed .     

Research on graphite powders used for HTR-PM fuel elements

Different batches of natural graphite powders and electrographite powders were characterized by impurity, degree of graphitization, particle size distribution, specific surface area, and shape characteristics. The graphite balls consist of proper mix-ratio of natural graphite, electrographite and phenolic resin were manufactured and characterized by thermal conductivity, anisotropy of thermal expansion, crush strength, and drop strength. Results show that some types of graphite powders possess very high purity, degree of graphitization, and sound size distribution and apparent density, which can serve for matrix graphite of HTR-PM. The graphite balls manufactured with reasonable mix-ratio of graphite powders and process method show very good properties. It is indicated that the properties of graphite balls can meet the design criterion of HTR-PM. We can provide a powerful candidate material for the future manufacture of HTR-PM fuel elements.     

墨水直写、喷墨打印和激光直写技术及其在微电子器件中的应用

直写技术是一种新型微加工技术,其加工过程不需模板并可在亚微米至厘米范围实现材料加工成型.墨水直写、喷墨打印和激光直写作为最常用的直写技术,具有强大的二维、三维成型能力和优异的成型精度,可实现金属、陶瓷、聚合物、水凝胶等复杂构型的程序化构筑,被广泛应用于微电子、组织工程、微流控等领域.阐述了这3种直写技术的构型原理和材料选择,重点介绍了其在微电子器件制造中的应用,讨论了当前研究的难点和热点问题,并对其未来发展趋势进行了展望.     

过渡金属有机框架结构构件及电解水研究进展

金属有机框架(MOF)材料由于其比表面积大、孔隙率高、结构可调控和单分散的活性中心等特性,在吸附分离、气体储存和电催化等领域具有巨大的应用前景,其中,在催化领域的应用尤为突出.目前,利用传统方法所制备的MOF虽然含有具有催化活性的金属,但是MOF中的金属位点通常和有机配体相结合,无法很好的暴露出来,导致在催化过程中表现...     

AlN/W多层体共烧过程中的应力

研究了１８５０℃高温烧结ＡｌＮ／Ｗ多层体烧结应力状态和产生原因,结果表明ＡｌＮ与Ｗ在１８５０℃共烧时,不同阶段烧结应力状态有所不同,在升温阶段,Ｗ层受平面拉应力作用,Ｗ层烧结速率降低,导致表面Ｗ膜内存在的大量空洞,而内部Ｗ布线受到径向拉应力的作用,在保温阶段,与表面Ｗ焊盘接触的ＡｌＮ受到拉应力的作用,与内部Ｗ线接触的ＡｌＮ受到环向拉应力的作用,由于环向拉应力的存在,导致ＡｌＮ的烧结速度帮烧结密度显