Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fu...Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carboFuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carbon dioxide.n dioxide.展开更多
Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the ...Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the commonly used bent tube to the size description range of(0,2.00).The evolution laws of the cross-section distortion forms in the hollow coefficient-bending degree interval are revealed as well as the action of the mandrel-cores on the size effect.Results show the mandrel-cores filling can expand the forming limit of the bent tube,but also bring two other forming defects of wrinkle and rupture.The identification factor(hollow coefficient multiply bending degree)provides a method for querying the cross-section distortion forms of all composite bending tubes.In the identification factor interval(0,1.00),the distribution area of bending forming defects of the composite tube is continuous.The thin-walled composite bending tube collapses when identification factor in(0,0.39),wrinkles when identification factor in[0.39,0.50),and ruptures when identification factor in[0.50,1.00).The mathematical model of size effect is derived,by which the average cross-section distortion rate is found to distribute like a radial leaf in the hollow coefficient-bending degree qualified forming space.The best forming zone is hollow coefficient 0.46-0.68,and bending degree 0.25-0.47.展开更多
In the context of China’s ongoing efforts to promote countryside revitalization and facilitate domestic economic circulation,it is of great significance to reduce the consumption disparity among rural households and ...In the context of China’s ongoing efforts to promote countryside revitalization and facilitate domestic economic circulation,it is of great significance to reduce the consumption disparity among rural households and unleash the consumption potential in the countryside.Based on data from China Family Panel Studies,this paper adopts a staggered difference-in-differences method to assess the impact of the e-commerce to enter rural areas on the consumption disparity among rural households.Findings:the comprehensive demonstration work of promoting e-commerce to enter rural areas has reduced the consumption disparity among rural households through the following mechanisms.Firstly,this policy initiative has mitigated the consumption-inhibiting effect on rural household consumption due to the local market size and external market accessibility by promoting the distribution of consumer goods to villages.Secondly,this policy initiative has also increased the agricultural income of rural households and reduced their consumption disparity by distributing farm produce to cities and enhancing the agricultural income of rural households.Moreover,the work is characterized by inclusive growth and is not susceptible to the“elite capture”phenomenon.展开更多
基金supported by the National Research Foundation of Korea (NRF2018M1A2A2063174)。
文摘Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carboFuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and safer.When fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and pollutants.Hence,their final product is only water,instead of pollutants like carbon dioxide.n dioxide.
基金co-supported by the National Natural Science Foundation of China(Nos.51601070 and 51875263)the Open Project of Guangdong Key Laboratory of Precision Equipment and Manufacturing Technology,China(No.PEMT202102)the Natural Science Foundation of Jiangsu Province,China(No.BK20181447)。
文摘Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the commonly used bent tube to the size description range of(0,2.00).The evolution laws of the cross-section distortion forms in the hollow coefficient-bending degree interval are revealed as well as the action of the mandrel-cores on the size effect.Results show the mandrel-cores filling can expand the forming limit of the bent tube,but also bring two other forming defects of wrinkle and rupture.The identification factor(hollow coefficient multiply bending degree)provides a method for querying the cross-section distortion forms of all composite bending tubes.In the identification factor interval(0,1.00),the distribution area of bending forming defects of the composite tube is continuous.The thin-walled composite bending tube collapses when identification factor in(0,0.39),wrinkles when identification factor in[0.39,0.50),and ruptures when identification factor in[0.50,1.00).The mathematical model of size effect is derived,by which the average cross-section distortion rate is found to distribute like a radial leaf in the hollow coefficient-bending degree qualified forming space.The best forming zone is hollow coefficient 0.46-0.68,and bending degree 0.25-0.47.
基金National Natural Science Foundation of China(NSFC)Youth Project“Research on Household Debt Behavior and Its Impact on Economic Inequality in the Context of Common Prosperity”(Grant No.72203136),the Youth Project of the Guangdong Planning Office of Philosophy and Social Science(GDPOPSS)“E-commerce Development and Consumption Disparity of Rural Households:Theoretical Mechanism,Empirical Test and Policy Optimization”(Grant No.GD24YYJ27).
文摘In the context of China’s ongoing efforts to promote countryside revitalization and facilitate domestic economic circulation,it is of great significance to reduce the consumption disparity among rural households and unleash the consumption potential in the countryside.Based on data from China Family Panel Studies,this paper adopts a staggered difference-in-differences method to assess the impact of the e-commerce to enter rural areas on the consumption disparity among rural households.Findings:the comprehensive demonstration work of promoting e-commerce to enter rural areas has reduced the consumption disparity among rural households through the following mechanisms.Firstly,this policy initiative has mitigated the consumption-inhibiting effect on rural household consumption due to the local market size and external market accessibility by promoting the distribution of consumer goods to villages.Secondly,this policy initiative has also increased the agricultural income of rural households and reduced their consumption disparity by distributing farm produce to cities and enhancing the agricultural income of rural households.Moreover,the work is characterized by inclusive growth and is not susceptible to the“elite capture”phenomenon.
