A series of copolyesters poly(ethylene terephthalate p-oxybenzoate) (PETO) de-rived from terephthalic acid, ethylene glycol and 4, 4’ -oxybis (benzoic acid) were easily pre-pared by using DMT method and thermally inv...A series of copolyesters poly(ethylene terephthalate p-oxybenzoate) (PETO) de-rived from terephthalic acid, ethylene glycol and 4, 4’ -oxybis (benzoic acid) were easily pre-pared by using DMT method and thermally investigated. Introduction of 4, 4’ -oxydipheny-lene group into the main chain resulted in a lowering of Tm. a decrease of crystallization rate and an increase of thermal-oxidative stability of the copolyesters. By static elongation of PETO, transparent films with qualified electrical properties and mechanical properties were easily obtained with film forming rate 100%. In comparison with poly (ethylene terephthalate) (PET) film, PETO film had obviously low Tm. and low crystallization temper-ature. Due to the presence of stable aromatic ether structure, decrease in Tm. could not lead to any reduction in thermal-oxidative stability, on the contrary, slight increase was ob-served. PETO film could be used in making heat resistant thick film for channel insulators of electric motor.展开更多
Purpose:This study investigates the role of the engineering education environment created by the implementation of the“Plan for Educating and Training Outstanding Engineers”(PETOE)on the professional capability deve...Purpose:This study investigates the role of the engineering education environment created by the implementation of the“Plan for Educating and Training Outstanding Engineers”(PETOE)on the professional capability development of engineering students from the perspective of students'experience.Design/Approach/Methods:This study uses data from the National Engineering Student Survey and multiple regression analysis to explore the role of institutional resources and support,teaching reforms,and interpersonal interaction on the professional development of engineering students.Findings:The opportunities for on-campus practical activities provided by the institution,content of the teachers'teaching,teaching methods,comprehensive coursework assessment,and interpersonal interactions contributed to the development of students'engineering competencies,with limited contributions from research-based teaching methods.Internship opportunities and international exchange environments were negatively associated with the development of engineering skills in an“unexpected”manner.OriginalityNalue:Focusing on students'experiences of engineering education reform,this study comprehensively evaluates the implementation of the reform measures adopted under PETOE.Furthermore,it assesses how corresponding changes in the general educational environment relate to students’professional capability development.Thus,this study addresses an important research gap in educational reformthe lack of domestic empirical studies in China.展开更多
文摘A series of copolyesters poly(ethylene terephthalate p-oxybenzoate) (PETO) de-rived from terephthalic acid, ethylene glycol and 4, 4’ -oxybis (benzoic acid) were easily pre-pared by using DMT method and thermally investigated. Introduction of 4, 4’ -oxydipheny-lene group into the main chain resulted in a lowering of Tm. a decrease of crystallization rate and an increase of thermal-oxidative stability of the copolyesters. By static elongation of PETO, transparent films with qualified electrical properties and mechanical properties were easily obtained with film forming rate 100%. In comparison with poly (ethylene terephthalate) (PET) film, PETO film had obviously low Tm. and low crystallization temper-ature. Due to the presence of stable aromatic ether structure, decrease in Tm. could not lead to any reduction in thermal-oxidative stability, on the contrary, slight increase was ob-served. PETO film could be used in making heat resistant thick film for channel insulators of electric motor.
基金supported by the Consulting Project of Chinese Academy of Engineering:Research on cultivating multi-directional thinking of engineering students for the digital-intelligence era(grant number 2021-XY-47).
文摘Purpose:This study investigates the role of the engineering education environment created by the implementation of the“Plan for Educating and Training Outstanding Engineers”(PETOE)on the professional capability development of engineering students from the perspective of students'experience.Design/Approach/Methods:This study uses data from the National Engineering Student Survey and multiple regression analysis to explore the role of institutional resources and support,teaching reforms,and interpersonal interaction on the professional development of engineering students.Findings:The opportunities for on-campus practical activities provided by the institution,content of the teachers'teaching,teaching methods,comprehensive coursework assessment,and interpersonal interactions contributed to the development of students'engineering competencies,with limited contributions from research-based teaching methods.Internship opportunities and international exchange environments were negatively associated with the development of engineering skills in an“unexpected”manner.OriginalityNalue:Focusing on students'experiences of engineering education reform,this study comprehensively evaluates the implementation of the reform measures adopted under PETOE.Furthermore,it assesses how corresponding changes in the general educational environment relate to students’professional capability development.Thus,this study addresses an important research gap in educational reformthe lack of domestic empirical studies in China.
