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151.
实验研究了由溶胶-凝胶法制备二氧化硅驻极体薄膜的工艺。用红外透射谱、扫描电子显微镜以及驻极体等温表面电位测量和热刺激放电等实验考察了热处理和化学表面修正两个关键工艺对溶胶-凝胶二氧化硅样品驻极体性能的影响。结果表明经过高温条件下一定时间的热处理和化学表面修正,可以制备出性能优良的驻极体薄膜  相似文献   
152.
用高效液相色谱分析农药三唑锡,采用强阳离子交换柱,甲醇、水、冰醋酸作流动相以及紫外检测器。结果表明,此法分离效果好,准确度和精密度高,可用于三唑锡生产控制及原药、各种制剂(粉剂、胶悬剂)产品分析。  相似文献   
153.
本文根据最新资料,综述了上前国内外半导体发光器件的现状和发展趋势,并对我国应如何发展光电器件提出建议。  相似文献   
154.
光导器件及其背景限探测度   总被引:1,自引:0,他引:1  
本文就MCT光导型探测器作一总结性的讨论,对光导器件的扫出问题作了更详尽的阐述,并定义了扫出因子。关于背景限探测度提出了新的见解,认为背景限探测度不是不可逾越。  相似文献   
155.
156.
Little has so far been known about the role of antigen-presenting cells (APCs) in the activation of T cells by superantigens. Recently several studies showed that superantigens could directly activate purified T cells in the presence of CD28 costimulation. Here we investigate V beta expression of T cells activated by the superantigen toxic shock syndrome toxin-1 (TSST-1), plus CD28 costimulation, in the absence of APCs. The aim of this study was to ask if TSST-1 activated purified T cells in the presence of CD28 costimulation with the same specificity as in the presence of APCs. We provide evidence that the specificity of TSST-1 to human V beta, in the presence of CD28 costimulation, is identical to that in the presence of APCs, with V beta 2 being significantly expanded. The results indicate that the main role of APCs in the superantigen-mediated T cell activation may be to provide T cells with CD28 costimulation.  相似文献   
157.
158.
A composite of O′SiAlON (Si2-xAlxN2-xO1+x, with x 0.14) reinforced with 20 vol.% SiC monofilaments was fabricated by hot-pressing, at 1600°C, for 2 h under 34 MPa pressure. The mechanical and interfacial properties of the composites, as-fabricated as well as post-oxidized, were, investigated. The composite exhibited a significant improvement in ultimate flexure strength (640 MPa) and work of fracture (42 kJ m−2) compared with that (350 MPa and 1.8 kJ m−2, respectively) of the monolithic material. These mechanical properties were slightly increased after the composite was heat treated for 24 h in air at 1200 and 1300°C. However, the composite exhibited a significant degradation in ultimate strength, while the work of fracture (WOF) remained unchanged after exposure in air at temperatures beyond 1400°C. The as-fabricated composite revealed a low interfacial shear strength (6.2 MPa) and a frictional sliding stress (3.2 MPa). After the composite was oxidized at elevated temperatures, the interfacial bonding and sliding stresses were reduced to noticeable extents, resulting from the degradation of the carbon coating layer of the SiC monofilaments.  相似文献   
159.
朱国海 《铁合金》2007,38(6):32-36
介绍了广西康密劳1^#锰铁高炉大修的方案选择和装备技术及今后技术进步方向。为我国其它锰铁高炉技术改造提供了一种参照方法。  相似文献   
160.
Imitated GE ware was one of the most famous products of Jingdezhen porcelain field in Ming dynasty (AD 1368-1644). The exterior features of its body and glaze are very marvelous. Black foot, purple mouth and crazing glaze are the main features of imitated GE ware. Until now, the key conditions of resulting these features are not clearly identified. In order to find the critical elements for firing these features, instrumental neutron activation analysis (INAA) and wavelength-dispersive X-ray fluorescence (WDXRF) were used to determine the element abundance patterns of imitated GE ware body and glaze. The experimental data was compared with that of imitated Longquan celadon and of Longquan celadon. The analytical results indicated that Fe, Ti and Na were the critical elements. The body of imitated GE ware which contains high Fe and Ti are the basic conditions of firing its black body, black foot and purple mouth. The glaze of imitated GE ware which contains high Na is the main condition of producing its crazing glaze. Na is the critical element which enlarges the difference in expansion coefficients between the glaze and body of imitated GE ware. Furthermore, Zijin soil was added into kaolin to make the body rich in Fe and Ti. And something which was rich in Na was used to produce crazing glaze in the manufacturing process of imitated GE ware.  相似文献   
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