关键词： 磁控溅射   复合薄膜   纳米颗粒   微结构  

摘要： 本文采用基片可旋转并利用红外灯管加热基片多靶磁控溅射台的制备了不同成分及基片温度的Ag～Sio2复合薄膜。采用XRD、TEM、SEM等手段分析了薄膜的微观组织结构，并测定了薄膜的电阻率。研究结果表明：复合薄膜的微结构由多晶富Ag区和细密的Ag晶体和非晶SiO2混合物组成；室温下随SiO2含量的增加．薄膜中金属Ag呈网状分布．晶粒细化，电阻率上升；随基片温度的升高．复合薄膜中银晶体最终聚集成孤立的纳米颗粒；与微结构相对应，薄膜的电阻率可在大范围（102～106μΩcm）内变化。

关键词： Magnetic materials  

摘要： Transmission electron microscopy has been used to study the magnetic domain structure and its evolution under an external applied field in thin sections of Nd-Fe-B-type magnets produced by the solid-HDDR process. Grain sizes in the recombined material were typically 200-800 nm and the orientation of the c axis varied by about 20 degrees over distances >20 mu m in an aligned region. Mean relative orientations of adjacent aligned regions within the sample varied to a much greater extent. In samples with the c axis inclined with respect to the plane of a thin section, an irregular periodic domain structure was observed. Boundaries between oppositely magnetized domains tended to lie along grain boundaries of the smaller grains. Domain walls were observed within the larger grains when a substantial disturbance of the domain structure would be required to reach a grain boundary. In situ magnetizing experiments showed that domain wails in the centres of grains tended to move until they reached grain boundaries, where they remained pinned;with higher fields occasional jumps from one grain boundary to the next were observed until an applied field that appeared to remove all the domain waifs in that region had been reached. Under the application of a reverse field, such that domain structures were observed, it was rare to find domain boundaries and grain boundaries which did not coincide. Restoration of the original state, with walls passing through the centres of grains, was only obtained by thermally demagnetizing the sample.

关键词： 几何描述   材料变形状态   材料微结构演化   纤维丛理论   规范结构  

摘要： 该文应用微分几何学中的纤维丛理论,从新的角度出发对含微结构材料的力学行为进行了研究.利用纤维丛理论所具有的处理相互联系的不同空间及其相关性质的特点,将含微结构材料的宏观和细观力学行为紧密结构起来,从而可以在统一的理论框架内对材料不同层次的力学性质进行研究.

关键词： 微型电子机械系统   传感器   施乐公司   技术   九十年代   计算机   模型   八十年代   微型芯片   立体交叉  

摘要： 在离世界闻名的圣安得里斯大断层仅5千米之遥的美国施乐公司的研究中心,摆放着一个极小但意义重大的模型。这个模型上布满着由电线相互连接的无数个微型婴儿奶嘴形状的传感器。将来。

关键词： co-sputtering   heat treatment   nanocomposite thin film   transmission electron microscopy  

摘要： Nanocomposite films consisting of silver and silicon were manufactured by r.f. co-sputtering deposition. The influence of substrate temperatures varying from 20 to 200 degrees C and different substrate materials such as cleaved NaCl crystals, C-coated Cu grids and (100) Si single-crystal wafers was investigated. Subsequent heat treatment at different temperatures ranging from 500 to 800 degrees C and its effect on the microstructure of the deposited films was also investigated by using a combination of differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, conventional transmission electron microscopy and high-resolution electron microscopy. The typical microstructure of the as-deposited film consisted of nanosized Ag particles embedded in an amorphous Si matrix. The crystallization temperature of the amorphous Si matrix was reduced from 550 to 490 degrees C with increasing Ag content in the films. The microstructure of the annealed Ag/Si film after crystallization consists of Si crystallites with sizes from several nanometres to hundreds of nanometres and Ag particles with average sizes from 12 nm (600 degrees C) to 28 nm (800 degrees C). Surface segregation of silver was also observed for the annealing temperatures of 600 degrees C and above. We suggest a possible explanation for the silver-induced lowering of the amorphous Si matrix crystallization temperature. (C) 1997 Elsevier Science S.A.

关键词： 骨折愈合   可吸收固定材料   超微结构  

摘要： 在25只大鼠股骨下端骨折模型中,运用可吸收固定物(SR—PGA)进行髓内固定。于固定后4、6、8、12、24周取骨折愈合区骨痂进行透射电镜观察。在超微结构中,作者发现可吸收固定物降解颗粒呈方形或棱形,排列有与胶原纤维纵轴方向平行趋向;机体对降解颗粒反应始终存在,尤其24周时仍可见吞噬细胞和其死亡的形态结构。结合骨折愈合理论作者认为在皮质骨、粉碎骨折及影响血供部位的骨折中,应用可吸收固定物应当慎重。

关键词： 飞机   摩擦材料   显微结构  

摘要： 本研究对Fe基和Fe－CU基两种飞机摩擦材料的显微结构及其受摩擦制动过程（摩擦热）的影响进行了金相观察和分析。研究结果表明，受摩擦制动过程的影响，Fe基摩擦材料的显微结构发生了较大的变化，组织中细片层珠光体明显增多，而FE-CU基摩擦材料的显微结构较稳定，未受摩擦热明显影响。金相观察还发现，Fe-cu基摩擦材料靠摩擦表面形成了薄的摩擦工作层，并且在表层和近表层还发生了再结晶过程，使晶粒明显细化。

关键词： 纳米固体材料   显微结构   高分辨   电子显微术  

摘要： 本文综述了利用高分辨电子显微术研究以三种不同工艺制备的纳米固体材料显微结构的结果。用惰性气体凝聚加压法、机械合金化及非晶晶化法制备的纳米晶样品中，多数晶界呈有序结构，但存在程度不等的点阵畸变，在前两种方法制备的样品中，还存在局部无序的晶界区域。晶界的有序程度依次为：非晶晶化法＞惰性气体凝聚加压法＞机械合金化法。用前两种方法制备的样品中还观察到大量的、室温下不常见的形变孪晶。在不同工艺制备的三种样品中，缺陷密度的高低依次为：机械合金化法＞惰性气体凝聚加压法＞非晶晶化法。对于非固溶二元体系，凝聚加压法较难形成明显的亚稳晶体相。

关键词： 莫来石   烧结   显微结构   凝胶法   陶瓷粉末  

摘要： 对用溶胶—凝胶法制备的莫来石先驱粉末的晶化及烧结行为进行了研究。先驱粉末在１０００℃煅烧１ｈ形成少量尖晶石，在更高的温度由这种尖晶石相及无定形ＳｉＯ２相形成莫来石，煅烧后的粉末具有很高的活性，在１５５０℃烧成０５ｈ，烧结体相对密度达到９８７％，陶瓷显微结构由细小等轴莫来石晶粒构成，随着烧成时间的延长或烧成温度的升高，烧结体中的柱状莫来石晶粒变得越来越多。

关键词： murine visceral leishmaniasis   pentamidine   drug carrier   election microscopy  

摘要： Drug targeting enhances drug efficacy. This principle was tested in the treatment of an experimental visceral leishmaniasis. Using transmission electron microscopy (TEM) we localized pentamidine-loaded polymethacrylate nanoparticles in the liver of mice infected with leishmania major and compared the ultrastructural changes in the parasites of these mice when they were treated with bound versus free pentamidine. Between days 13 and 17 after infection, loaded nanoparticles treated group were injected i.v. with 3 doses of 0.17 mg/kg bound pentamidine loaded on 2 x 10(11) nanospheres;control groups received 2 x 10(11) unloaded nanospheres. Drug reference control groups received five doses of 200 mg/kg pentavalent antimony (Glycantime(R)) or three doses of free pentamidine (0.17 mg/kg or 2.28 mg/kg). Mice treated with bound pentamidine displayed a 77% reduction in their parasite burden versus the untreated controls. Nanoparticles were located by TEM inside parasitized Kupffer cells, in the phagolysosomes without entering the Leishmania. The low dose of 0.17 mg/kg bound pentamidine damaged the Leishmania to the same extent as 2.28 mg/kg of free pentamidine (the usual dose in human chemotherapy). In the parasites inside the Kupffer cells, TEM showed a swollen mitochondrion with loss of cristae, destruction or fragmentation of the kinetoplast, loss of ribosomes and destruction of parasite structures except for the subpellicular microtubules. This study therefore shows that a dose of bound pentamidine 13 times smaller than the usual dose of free pentamidine has a similar effect on the parasite.