Structural and electrical properties of crystalline (1−x)Ta2O5−xTiO2 thin films fabricated by metalorganic decomposition

Polycrystalline (1−x)Ta₂O₅−xTiO₂ thin films were formed on Si by metalorganic decomposition (MOD) and annealed at various temperatures. As-deposited films were in the amorphous state and were completely transformed to crystalline after annealing above 600 °C. During crystallization, a thin interfacial SiO₂ layer was formed at the (1−x)Ta₂O₅−xTiO₂/Si interface. Thin films with 0.92Ta₂O₅–0.08TiO₂ composition exhibited superior insulating properties. The measured dielectric constant and dissipation factor at 1 MHz were 9 and 0.015, respectively, for films annealed at 900 °C. The interface trap density was 2.5×10¹¹ cm⁻² eV⁻¹, and flatband voltage was −0.38 V. A charge storage density of 22.8 fC/μm² was obtained at an applied electric field of 3 MV/cm. The leakage current density was lower than 4×10⁻⁹ A/cm² up to an applied electric field of 6 MV/cm.     

3D-shaping of biodegradable photopolymers for hard tissue replacement

Continuously increasing life expectancy results in a rising number of bone diseases and fractures. Replacements from natural sources are not only limited in their availability, they also have some serious disadvantages such as possible immunological reactions or transmission of diseases. New synthetic biodegradable materials based on photopolymers could be an alternative solution. In these investigations an acrylate-based monomer formulation has been developed, consisting of a biodegradable basis monomer which is derived from gelatin, different reactive diluents, an appropriate photoinitiator and filler materials. For the three-dimensional shaping process stereolithography is the method of choice because of its capability to produce cellular structures with high resolutions.     

第一壁材料用纳米结构氧化物弥散强化钢制备工艺及其性能研究进展

近年来发展起来的纳米结构氧化物弥散强化钢(ODS钢),因其有优异的耐高温、抗辐照及力学性能,满足聚变堆第一壁结构材料的要求。本文主要简述了纳米结构ODS钢制备工艺及其性能的研究进展。     

Influence of magnetic powders on the tribological performance of a novel magnetic brake material

By adding magnetic powders into matrix material, it has been proved to be a creative approach to improve tribological properties of brake materials. In this paper, a novel magnetic brake material with Nd–Fe–B and nano-Fe₃O₄ was developed, and the influential mechanism of these two magnetic powders and their content on the friction and wear performance was deeply discussed. Firstly, some experiments were carried out to investigate the tribological performance and influential mechanisms of four groups of brake pad samples with different magnetic powders. Furthermore, based on these results, further experiments for investigating the influence that Nd–Fe–B contents have on the tribological properties were conducted. According to the theoretical analysis about experiments, it was concluded that nano-Fe₃O₄ is beneficial to promote the formation of friction film and has certain lubricant effects. However, Nd–Fe–B has double effects on the formation of friction film. It will have positive effects when its content is less than a certain value. Otherwise, it will destroy the structure of friction film. Conclusively, it is believed that this study will be significantly valuable and meaningful for developing new brake materials and improving safety reliability of mechanical brakes.     

Reduction in etching time for fission tracks in diallyl phthalate resin

Diallyl phthalate (DAP) resin plates were irradiated with fission fragments, and then etched in a conventional aqueous solution of KOH or a PEW solution containing ethanol, water and KOH. Etched tracks were observed and counted by using an optical microscope. The PEW solution made the fission tracks etch-pits clearer in an incomparably shorter etching time. The large and round etch-pits developed on a smooth surface were convenient for optical automatic counting. These etching characteristics of DAP in a PEW solution are suitable for quantitative analysis of fissionable materials and neutron dosimetry.     

半球蓝宝石整流罩制造技术研究

整流罩在高速飞行中既要对空气进行整流,同时又起光学窗口的作用。蓝宝石材料硬度高,加工非常困难。分别从精磨模、精磨磨料、抛光膜层、抛光辅料、机床速度和压力等方面介绍了一种加工蓝宝石整流罩的工艺方法。     

左手介质椭圆光波导基模传播特性

在椭圆柱坐标系中,采用分离变量方法,得出了左手介质椭圆光波导本征方程的近似解,通过数值计算,分析了椭圆波导偏心率、左手介质的电容率、磁导率对椭圆光波导基模传播特性的影响,并将左介质光波导与右手介质光波导基模特性进行对比,得出左手介质光波导的基模特性与右手介质光波导基模特性差别不大的结论.     

硬X射线磁圆二色实验方法的建立

在北京同步辐射装置(BSRF)1W1B光束线和XAFS实验站上国内首次建立了硬X射线波段的磁圆二色实验(XMCD)方法. 以单晶金刚石作为相位延迟片, 在透射劳埃(Laue)模式下, 利用衍射双折射效应, 将入射的单色线偏振光转变为相应的左旋和右旋圆偏振光, 测量磁化样品对左旋和右旋圆偏振光吸收的差异, 获得了XMCD信号. 本实验使用透射方法测量了Pt-Fe合金Pt L_2,3边的XMCD, 获得了XMCD信号. XMCD实验方法的建立, 为研究磁性材料尤其是磁性薄膜材料的电子结构和磁结构提供了实验基础.     

聚合物纳米孔隙增透膜制备工艺的研究

论述了聚合物纳米孔隙增透膜的制备工艺流程,分析了聚合物材料分子量、实验环境温度和湿度、溶剂挥发性等条件对纳米孔隙增透膜的影响。研究表明,聚合物材料分子量的增大、温度的降低、湿度的升高以及采用挥发性弱的溶剂都将导致增透膜孔隙尺寸的增大,孔隙越大其对光的散射损耗就会增大,所以增透膜的透过率就越低。通过大量的试验分析得出一组较理想的工艺参量:使用低分子量的聚合物材料(小于15 kg/mol),环境温度大于25℃、环境相对湿度小于30%,在采用低沸点的溶剂如四氢呋喃等措施下可有效降低增透膜散射损耗。