Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resista...Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resistance and low-temperature resistance,respectively.In order to develop type 120 emergency valverubber diaphragms with long-life and high-performance,low-temperatureresistant CR and NR were processed.Design/methodology/approach–The physical properties of the low-temperature-resistant CR and NRwere tested by low-temperature stretching,dynamic mechanical analysis,differential scanning calorimetryand thermogravimetric analysis.Single-valve and single-vehicle tests of type 120 emergency valves werecarried out for emergency diaphragms consisting of NR and CR.Findings–The low-temperature-resistant CR and NR exhibited excellent physical properties.The elasticityand low-temperature resistance of NR were superior to those of CR,whereas the mechanical properties of thetwo rubbers were similar in the temperature range of 0℃–150℃.The NR and CR emergency diaphragms metthe requirements of the single-valve test.In the low-temperature single-vehicle test,only the low-temperaturesensitivity test of the NR emergency diaphragm met the requirements.Originality/value–The innovation of this study is that it provides valuable data and experience for futuredevelopment of type 120 valve rubber diaphragms.展开更多
The e-commerce standard internationalization has become the strategic targets of China’s digital economy.This paper proposes the system dynamics model through analyzing the internal and external factors of e-commerce...The e-commerce standard internationalization has become the strategic targets of China’s digital economy.This paper proposes the system dynamics model through analyzing the internal and external factors of e-commerce standard internationalization under dynamic mechanism.The internationalization trend of China’s e-commerce standard is simulated by Vensim under adjusting economy factor,policy support factor,technical-innovation factor and industry supply chain’s service factor.The experiment results show that China’s international leadership on e-commerce and its influence on standard internationalization from the top-level design,strengthen industry supply chain’s standard certification and the technical-innovation of product standard factors,which can promote the high quality made-in-China brand.展开更多
基金funded by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.N2023J053).
文摘Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resistance and low-temperature resistance,respectively.In order to develop type 120 emergency valverubber diaphragms with long-life and high-performance,low-temperatureresistant CR and NR were processed.Design/methodology/approach–The physical properties of the low-temperature-resistant CR and NRwere tested by low-temperature stretching,dynamic mechanical analysis,differential scanning calorimetryand thermogravimetric analysis.Single-valve and single-vehicle tests of type 120 emergency valves werecarried out for emergency diaphragms consisting of NR and CR.Findings–The low-temperature-resistant CR and NR exhibited excellent physical properties.The elasticityand low-temperature resistance of NR were superior to those of CR,whereas the mechanical properties of thetwo rubbers were similar in the temperature range of 0℃–150℃.The NR and CR emergency diaphragms metthe requirements of the single-valve test.In the low-temperature single-vehicle test,only the low-temperaturesensitivity test of the NR emergency diaphragm met the requirements.Originality/value–The innovation of this study is that it provides valuable data and experience for futuredevelopment of type 120 valve rubber diaphragms.
基金supported by the Zhejiang Provincial Philosophy and Social Science Planning Project of China(Grant No.20NDJC096YB)the National Key Research and Development Project of China(Grant No.2017YFF0209600)
文摘The e-commerce standard internationalization has become the strategic targets of China’s digital economy.This paper proposes the system dynamics model through analyzing the internal and external factors of e-commerce standard internationalization under dynamic mechanism.The internationalization trend of China’s e-commerce standard is simulated by Vensim under adjusting economy factor,policy support factor,technical-innovation factor and industry supply chain’s service factor.The experiment results show that China’s international leadership on e-commerce and its influence on standard internationalization from the top-level design,strengthen industry supply chain’s standard certification and the technical-innovation of product standard factors,which can promote the high quality made-in-China brand.
