尝试采用自蔓延高温合成 (SHS)、具有近球形特征且表面粗糙的新型 Si C颗粒 ,以替代传统的角状磨料级 Si C颗粒 ,作为光学 /仪表级的高体分 Si Cp/Al复合材料的增强体。研究结果表明 :与传统角状 Si C颗粒相比 ,SHS- Si C颗粒的无棱角...尝试采用自蔓延高温合成 (SHS)、具有近球形特征且表面粗糙的新型 Si C颗粒 ,以替代传统的角状磨料级 Si C颗粒 ,作为光学 /仪表级的高体分 Si Cp/Al复合材料的增强体。研究结果表明 :与传统角状 Si C颗粒相比 ,SHS- Si C颗粒的无棱角、近球形几何特征 ,使其附近铝基体中的应力集中程度显著降低 ,进而使材料的强度包括表征尺寸稳定性的微屈服强度明显提高 ;SHS- Si C颗粒所特有的粗糙表面形貌 ,使 Si C- Al之间的界面结合通过机械镶嵌机制得到了进一步的增强 ,跨越界面的载荷传递效率进一步提高 。展开更多
A surface photocatalysis-TPD apparatus devoted to studying kinetics and mechanism of pho- tocatalytic processes with various signal crystal surfaces has been constructed. Extremely high vacuum （-0.2 nPa） in the ioni...A surface photocatalysis-TPD apparatus devoted to studying kinetics and mechanism of pho- tocatalytic processes with various signal crystal surfaces has been constructed. Extremely high vacuum （-0.2 nPa） in the ionization region is obtained by using multiple ultrahigh vacuum pumps. Compared with similar instruments built previously by others~ the H2, CH4 background in the ionization region can be reduced by about two orders of magnitude, and other residual gases in the ionization region can be reduced by about an order of magnitude. Therefore, the signal-to-noise ratio for the temperature programmed desorption （TPD） and time of flight （TOF） spectra is substantially enhanced, making experimental studies of pho- tocatalytic processes on surfaces much easier. In this work, we describe the new apparatus in detail and present some preliminary studies on the photo-induced oxygen vacancy defects on TiO2（110） at 266 nm by using the TPD and TOF methods. Preliminary results suggest that the apparatus is a powerful tool for studying kinetics and mechanism of photochemical processes.展开更多
文摘尝试采用自蔓延高温合成 (SHS)、具有近球形特征且表面粗糙的新型 Si C颗粒 ,以替代传统的角状磨料级 Si C颗粒 ,作为光学 /仪表级的高体分 Si Cp/Al复合材料的增强体。研究结果表明 :与传统角状 Si C颗粒相比 ,SHS- Si C颗粒的无棱角、近球形几何特征 ,使其附近铝基体中的应力集中程度显著降低 ,进而使材料的强度包括表征尺寸稳定性的微屈服强度明显提高 ;SHS- Si C颗粒所特有的粗糙表面形貌 ,使 Si C- Al之间的界面结合通过机械镶嵌机制得到了进一步的增强 ,跨越界面的载荷传递效率进一步提高 。
文摘A surface photocatalysis-TPD apparatus devoted to studying kinetics and mechanism of pho- tocatalytic processes with various signal crystal surfaces has been constructed. Extremely high vacuum （-0.2 nPa） in the ionization region is obtained by using multiple ultrahigh vacuum pumps. Compared with similar instruments built previously by others~ the H2, CH4 background in the ionization region can be reduced by about two orders of magnitude, and other residual gases in the ionization region can be reduced by about an order of magnitude. Therefore, the signal-to-noise ratio for the temperature programmed desorption （TPD） and time of flight （TOF） spectra is substantially enhanced, making experimental studies of pho- tocatalytic processes on surfaces much easier. In this work, we describe the new apparatus in detail and present some preliminary studies on the photo-induced oxygen vacancy defects on TiO2（110） at 266 nm by using the TPD and TOF methods. Preliminary results suggest that the apparatus is a powerful tool for studying kinetics and mechanism of photochemical processes.
