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101.
Amara Sif Eddine Kesri Rafika Valignat Nicole Hamar-Thibault Sylvaine 《Mikrochimica acta》1994,114(1):157-164
The solidification behaviour of Fe-V-C alloys, was studied by differential thermal analysis. The composition and the nature of the phases were analysed by quantitative electron probe microanalysis and X-ray diffraction. Accurate microanalysis of carbon in vanadium carbides (VCx and V2C) were performed. A liquidus projection of the system Fe-V-C in the Fe-V rich region was proposed. 相似文献
102.
SUN Jing 《Chinese Journal of Lasers》1998,7(5):445-450
1IntroductionStudiesonlaserheattreatmentofcementedcarbidehavebencariedoutbymanyresearchers.Cementedcarbideismadebysinteringth... 相似文献
103.
High Resolution Electron Microscopy on Yttrium Iodide Carbide Oxides An investigation on the real structure of the yttrium iodide carbide oxides has been carried out by means of HRTEM. In the structures planar layer fragments with the general composition Y2I2C are linked via chains of corner sharing Y4O tetrahedra building corrugated layers. A sequence of compounds with the general formula (Y2I2C)nYO can be derived where n denotes the number of linked octahedra chains in the plane sections, and thus represents their width. Irregularities concerning the width of the planar segments have been detected. Besides the so far known members of the series Y7I6C3O und Y9I8C4O, with n = 3 and 4, respectively, an additional ordered compound with alternating 3 and 4 octahedra chains has been found. The introduction of the samples, which are very sensitive to air and moisture, into the microscope has been realised using a specially designed transfer system. 相似文献
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106.
Ming‐Yi Chen Jian‐Xun Wang Kung‐Tung Chen Bi‐Zhou Wen Wei‐Chieh Lin Chiing‐Chang Chen 《中国化学会会志》2012,59(2):170-175
Calcium carbide residue (CCR) was investigated in transesterification reaction of triglycerides to determine its viability as a solid catalyst for biodiesel synthesis. Literature survey showed that CCR has never been studied as a solid catalyst in the transesterification of triglyceride. The scope of the study includes the effects of CCR calcination temperature, calcination time, the alcohol/oil molar ratio, the catalyst amount (wt % of oil) and the reaction time. The relationship between chemical composition and catalytic activity of waste cement was also investigated. These CCR catalysts, thermally activated at 600 °C, can give rise to fatty acid methyl esters (FAME) purity higher than 99.5%, after 3 h of reaction, when oil/methanol molar ratio of 1/12 and 1 wt % of the catalyst were employed. Application of CCR as catalyst for biodiesel production in this study may not only provide a cost‐effective and environment friendly way of recycling CCR waste but also reduce hopefully the cost of biodiesel production. 相似文献
107.
以HZSM-5(SiO2/Al2O3=38)为载体,偏钨酸铵为钨源制备了双功能催化剂WC/HZSM-5,考察了其催化正己烷芳构化反应性能,并采用X射线衍射、扫描电子显微镜、X射线能量散射谱和程序升温氨脱附等手段对催化剂进行了表征,探讨了制备方法和WC含量对WC/HZSM-5催化剂性能的影响.结果表明,采用原位还原碳化法制备的WC/HZSM-5(RC)催化剂上正己烷芳构化反应性能优于浸渍法制备的WC/HZSM-5(IP).5%WC/HZSM-5(RC)样品在反应初始阶段芳烃选择性为10.28%,而HZSM-5上的仅为2.56%.WC/HZSM-5(RC)催化剂上反应产物中轻质芳烃(苯、甲苯和二甲苯)含量增加,重质芳烃C9+含量降低,其催化性能优于Pt/HZSM-5催化剂.产物分布的变化可能是由于WC与分子筛间的协同作用所致. 相似文献
108.
The effect of low energy sputtering under grazing incidence upon the surface composition of SiC was investigated by Auger electron spectroscopy. The energy of the sputtering projectiles (He, Ar) varied from 200 to 1500?eV. Peak shifts to the higher energies with increasing argon ion energy were observed for all silicon and carbon Auger transitions. These shifts were explained by enhanced damage of the surface region within the sampling depth of the Auger electrons. The insensitivity of the Auger peak position to the energy of helium ions indicates that the damage state in the surface region does not change with the increasing energy of helium ions. An increase of the carbon concentration with the decrease of the argon energy was observed. The experiments were accompanied by dynamic Monte Carlo simulations by the TRIDYN code. 相似文献
109.
应用碳化硅表面改性技术降低全息-离子束刻蚀光栅刻槽的粗糙度 总被引:1,自引:0,他引:1
采用具有良好比刚度和热稳定性的碳化硅材料作为基底,使用全息-离子束刻蚀技术制作了光栅。碳化硅材料表面固有缺陷导致制作的光栅刻槽表面粗糙度高,槽底和槽顶粗糙度分别达到了29.6 nm和65.3 nm (Rq)。通过等离子辅助沉积技术在碳化硅表面镀制一层均匀的硅改性层,经过抛光可以获得无缺陷的超光滑表面。XRD测试表明制备的硅改性层为无定形结构。原子力显微镜的测试结果表明:经过抛光后,表面粗糙度为0.64 nm(Rq)。在此表面上制作的光栅刻槽表面粗糙度明显降低,槽底和槽顶粗糙度分别为2.96 nm和7.21 nm,相当于改性前的1/10和1/9。 相似文献
110.