Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fractur...Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.展开更多
语言游戏是那些想使语言教学更有意义更有趣的教师的出色帮手。 Elizabeth Rowell 目前,许多英语教师还沿用着传统的教学法。在使用这种教学法的课堂里,经常是教师竭尽全力,满堂一人言。课堂气氛既沉闷又压抑。学生被视为被动的知识接收...语言游戏是那些想使语言教学更有意义更有趣的教师的出色帮手。 Elizabeth Rowell 目前,许多英语教师还沿用着传统的教学法。在使用这种教学法的课堂里,经常是教师竭尽全力,满堂一人言。课堂气氛既沉闷又压抑。学生被视为被动的知识接收器,而非活生生、有思想有感情的人,其学习主动性远远没有调动起来。本文拟就如何使用英语语言游戏来打破传统课堂的沉闷局面,让学生有一个轻松愉快的学英语气氛。作如下几点讨论。展开更多
Phase separation was studied by the optical microscopy in blends of nylon 6 (PA6) with sodium salt of ethylene/methacrylic acid copolymer (PEMA).The image collecting technology was used to keep track of the developme...Phase separation was studied by the optical microscopy in blends of nylon 6 (PA6) with sodium salt of ethylene/methacrylic acid copolymer (PEMA).The image collecting technology was used to keep track of the development of blends at a certain temperature.The fractal dimension of phase separation was calculated by the image solving technology according to the fractal theory and the self similarity behavior of the process was proved.The relationship of the fractal behavior with composition and experimental temperature was discussed.The fractal behavior of the crystallization development of the crystal phase of PA6 in blends was also discussed and the fractal behavior calculated.展开更多
文摘Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.
文摘语言游戏是那些想使语言教学更有意义更有趣的教师的出色帮手。 Elizabeth Rowell 目前,许多英语教师还沿用着传统的教学法。在使用这种教学法的课堂里,经常是教师竭尽全力,满堂一人言。课堂气氛既沉闷又压抑。学生被视为被动的知识接收器,而非活生生、有思想有感情的人,其学习主动性远远没有调动起来。本文拟就如何使用英语语言游戏来打破传统课堂的沉闷局面,让学生有一个轻松愉快的学英语气氛。作如下几点讨论。
文摘Phase separation was studied by the optical microscopy in blends of nylon 6 (PA6) with sodium salt of ethylene/methacrylic acid copolymer (PEMA).The image collecting technology was used to keep track of the development of blends at a certain temperature.The fractal dimension of phase separation was calculated by the image solving technology according to the fractal theory and the self similarity behavior of the process was proved.The relationship of the fractal behavior with composition and experimental temperature was discussed.The fractal behavior of the crystallization development of the crystal phase of PA6 in blends was also discussed and the fractal behavior calculated.
