Urban traffic and urban environmental pollution are important issues that must be taken into account in the process of urbanization,especially in China.Modernization has enabled many developed countries in the west to...Urban traffic and urban environmental pollution are important issues that must be taken into account in the process of urbanization,especially in China.Modernization has enabled many developed countries in the west to carry out rational city traffic planning.At the same time,the concept of green transportation has also emerged,integrating low-energy consumption,low pollution,comfort,and safety into urban traffic to effectively solve issues pertaining to traffic and pollution.The concept of green transportation has been widely adopted in China and made popular in many cities,thereby promoting the sustainable development of cities.展开更多
Currently urban issues show a dramatically increasing rely on auto use,which seriously affects the sustainable development of the city and makes how to build low-carbon cities become one of the urgent problems to be s...Currently urban issues show a dramatically increasing rely on auto use,which seriously affects the sustainable development of the city and makes how to build low-carbon cities become one of the urgent problems to be solved in the process of urban development.Therefore,low-carbon cities have become principles for China’s next generation of growth and the research hot spot of urban traffic planning.By taking a look at the concepts such as Compact City,transit-oriented development(TOD)city and‘small block’zoning,the article combined the relationship between urban spatial layout patterns and traffic development mode to build a green,low-carbon and sustainable urban development model.Finally,taking the urban design of the new district in the east of Handan City as an example,this research applied the concepts and approaches to planning practice,hoping to provide reference for building low carbon cities.展开更多
We adopt a self-consistent real space Kerker method to prevent the divergence from charge sloshing in the simulating transistors with realistic discrete dopants in the source and drain regions. The method achieves eff...We adopt a self-consistent real space Kerker method to prevent the divergence from charge sloshing in the simulating transistors with realistic discrete dopants in the source and drain regions. The method achieves efficient convergence by avoiding unrealistic long range charge sloshing but keeping effects from short range charge sloshing. Numerical results show that discrete dopants in the source and drain regions could have a bigger influence on the electrical variability than the usual continuous doping without considering charge sloshing. Few discrete dopants and the narrow geometry create a situation with short range Coulomb screening and oscillations of charge density in real space. The dopants induced quasilocalized defect modes in the source region experience short range oscillations in order to reach the drain end of the device.The charging of the defect modes and the oscillations of the charge density are identified by the simulation of the electron density.展开更多
We investigate the time-modulated electronic and spin transport properties through two T-shaped three-quantum-dot molecules embedded in an Aharonov-Bohm(A-B) interferometer. By using the Keldysh non-equilibrium Gree...We investigate the time-modulated electronic and spin transport properties through two T-shaped three-quantum-dot molecules embedded in an Aharonov-Bohm(A-B) interferometer. By using the Keldysh non-equilibrium Green's function technique, the photon-assisted spin-dependent average current is analyzed. The T-shaped three-quantum-dot molecule A-B interferometer exhibits excellent controllability in the average current resonance spectra by adjusting the interdot coupling strength, Rashba spin-orbit coupling strength, magnetic flux, and amplitude of the time-dependent external field.Efficient spin filtering and multiple electron-photon pump functions are exploited in the multi-quantum-dot molecule A-B interferometer by a time-modulated external field.展开更多
It is urgent and important to explore the dynamic evolution in comprehensive transportation green efficiency(CTGE)in the context of green development.We constructed a social development index that reflects the social ...It is urgent and important to explore the dynamic evolution in comprehensive transportation green efficiency(CTGE)in the context of green development.We constructed a social development index that reflects the social benefits of transportation services,and incorporated it into the comprehensive transportation efficiency evaluation framework as an expected output.Based on the panel data of 30 regions in China from 2003-2018,the CTGE in China was measured using the slacks-based measure-data envelopment analysis(SBM-DEA)model.Further,the dynamic evolution trends of CTGE were determined using the spatial Markov model and exploratory spatio-temporal data analysis(ESTDA)technique from a spatio-temporal perspective.The results showed that the CTGE shows a U-shaped change trend but with an overall low level and significant regional differences.The state transition of CTGE has a strong spatial dependence,and there exists the phenomenon of“club convergence”.Neighbourhood background has a significant impact on the CTGE transition types,and the spatial spillover effect is pronounced.The CTGE has an obvious positive correlation and spatial agglomeration characteristics.The geometric characteristics of the LISA time path show that the evolution process of local spatial structure and local spatial dependence of China’s CTGE is stable,but the integration of spatial evolution is weak.The spatio-temporal transition results of LISA indicate that the CTGE has obvious transfer inertness and has certain path-dependence and spatial locking characteristics,which will become the major difficulty in improving the CTGE.展开更多
文摘Urban traffic and urban environmental pollution are important issues that must be taken into account in the process of urbanization,especially in China.Modernization has enabled many developed countries in the west to carry out rational city traffic planning.At the same time,the concept of green transportation has also emerged,integrating low-energy consumption,low pollution,comfort,and safety into urban traffic to effectively solve issues pertaining to traffic and pollution.The concept of green transportation has been widely adopted in China and made popular in many cities,thereby promoting the sustainable development of cities.
基金Training Project of School of Architecture and Art,Hebei University of Engineering(2020-KJZD-001).
文摘Currently urban issues show a dramatically increasing rely on auto use,which seriously affects the sustainable development of the city and makes how to build low-carbon cities become one of the urgent problems to be solved in the process of urban development.Therefore,low-carbon cities have become principles for China’s next generation of growth and the research hot spot of urban traffic planning.By taking a look at the concepts such as Compact City,transit-oriented development(TOD)city and‘small block’zoning,the article combined the relationship between urban spatial layout patterns and traffic development mode to build a green,low-carbon and sustainable urban development model.Finally,taking the urban design of the new district in the east of Handan City as an example,this research applied the concepts and approaches to planning practice,hoping to provide reference for building low carbon cities.
基金Project supported by the National Natural Science Foundation of China(Grant No.11104069)
文摘We adopt a self-consistent real space Kerker method to prevent the divergence from charge sloshing in the simulating transistors with realistic discrete dopants in the source and drain regions. The method achieves efficient convergence by avoiding unrealistic long range charge sloshing but keeping effects from short range charge sloshing. Numerical results show that discrete dopants in the source and drain regions could have a bigger influence on the electrical variability than the usual continuous doping without considering charge sloshing. Few discrete dopants and the narrow geometry create a situation with short range Coulomb screening and oscillations of charge density in real space. The dopants induced quasilocalized defect modes in the source region experience short range oscillations in order to reach the drain end of the device.The charging of the defect modes and the oscillations of the charge density are identified by the simulation of the electron density.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11447132 and 11504042)the Natural Science Foundation of Heilongjiang,China(Grant No.A201405)+2 种基金111 Project to Harbin Engineering University,China(Grant No.B13015)Chongqing Science and Technology Commission Project,China(Grant Nos.cstc2014jcyj A00032 and cstc2016jcyj A1158)Scientific Research Project for Advanced Talents of Yangtze Normal University,China(Grant No.2017KYQD09)
文摘We investigate the time-modulated electronic and spin transport properties through two T-shaped three-quantum-dot molecules embedded in an Aharonov-Bohm(A-B) interferometer. By using the Keldysh non-equilibrium Green's function technique, the photon-assisted spin-dependent average current is analyzed. The T-shaped three-quantum-dot molecule A-B interferometer exhibits excellent controllability in the average current resonance spectra by adjusting the interdot coupling strength, Rashba spin-orbit coupling strength, magnetic flux, and amplitude of the time-dependent external field.Efficient spin filtering and multiple electron-photon pump functions are exploited in the multi-quantum-dot molecule A-B interferometer by a time-modulated external field.
基金National Key Research and Development Program of China(2019YFB1600400)National Natural Science Foundation of China(72174035)+2 种基金National Natural Science Foundation of China(71774018)Liaoning Revitalization Talents Program(XLYC2008030)Liaoning Provincial Natural Science Foundation Shipping Joint Foundation Program(2020-HYLH-20)。
文摘It is urgent and important to explore the dynamic evolution in comprehensive transportation green efficiency(CTGE)in the context of green development.We constructed a social development index that reflects the social benefits of transportation services,and incorporated it into the comprehensive transportation efficiency evaluation framework as an expected output.Based on the panel data of 30 regions in China from 2003-2018,the CTGE in China was measured using the slacks-based measure-data envelopment analysis(SBM-DEA)model.Further,the dynamic evolution trends of CTGE were determined using the spatial Markov model and exploratory spatio-temporal data analysis(ESTDA)technique from a spatio-temporal perspective.The results showed that the CTGE shows a U-shaped change trend but with an overall low level and significant regional differences.The state transition of CTGE has a strong spatial dependence,and there exists the phenomenon of“club convergence”.Neighbourhood background has a significant impact on the CTGE transition types,and the spatial spillover effect is pronounced.The CTGE has an obvious positive correlation and spatial agglomeration characteristics.The geometric characteristics of the LISA time path show that the evolution process of local spatial structure and local spatial dependence of China’s CTGE is stable,but the integration of spatial evolution is weak.The spatio-temporal transition results of LISA indicate that the CTGE has obvious transfer inertness and has certain path-dependence and spatial locking characteristics,which will become the major difficulty in improving the CTGE.