With a new nonperturbative method,the problem of persistent currents in one-dimensional mesoscopic rings with consideration of electron-phonon coupling is exactly solved and the energy spectrum is obtained.The result ...With a new nonperturbative method,the problem of persistent currents in one-dimensional mesoscopic rings with consideration of electron-phonon coupling is exactly solved and the energy spectrum is obtained.The result of this paper means that in the case of tight-binding model consideration of persistent currents can be treated separately from the interaction of electronphonon interaction.展开更多
Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The result...Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The results show that during the study period,total emergy input basically remained stable,but the emergy input structure was constantly optimized,of which the input of non-renewable industrial assistant emergy increased by 38.4%,from 4.00E +22 sej to 5.53E +22 sej,and the input of renewable organic emergy declined from 1.32E +23 sej to 1.20E + 23 sej;total emergy yield and yield efficiency of this system were promoted dramatically,and in 2008,the total emergy yield reached 1.69E +23 sej,increasing by 23.8% as against that in 1999,the net emergy yield ratio rose from 0.79 to 0.96;since the environmental loading ratio also tended to rise constantly,from 1.12 to 1.79,the sustainability index of this system also experienced the slow downward trend,from 0.71 to 0.54,always less than 1,indicating that the agriculture in Hunan Province is the high consumption-driven ecosystem in general,with obvious features of extensive development.展开更多
文摘With a new nonperturbative method,the problem of persistent currents in one-dimensional mesoscopic rings with consideration of electron-phonon coupling is exactly solved and the energy spectrum is obtained.The result of this paper means that in the case of tight-binding model consideration of persistent currents can be treated separately from the interaction of electronphonon interaction.
基金Supported by National Social Science Foundation (11BJY029)Hunan Social Science Fund Project (2010YBB348)+1 种基金Open Fund for Hunan University Innovation Platform (10K080)Key Project of Soft Science in Hunan Province (2011ZK2046)
文摘Using the emergy analysis method,we conduct trend analysis of changes in the total emergy,input and output structure,various emergy indicators of agro-ecosystem in Hunan Province during the period 1999-2008.The results show that during the study period,total emergy input basically remained stable,but the emergy input structure was constantly optimized,of which the input of non-renewable industrial assistant emergy increased by 38.4%,from 4.00E +22 sej to 5.53E +22 sej,and the input of renewable organic emergy declined from 1.32E +23 sej to 1.20E + 23 sej;total emergy yield and yield efficiency of this system were promoted dramatically,and in 2008,the total emergy yield reached 1.69E +23 sej,increasing by 23.8% as against that in 1999,the net emergy yield ratio rose from 0.79 to 0.96;since the environmental loading ratio also tended to rise constantly,from 1.12 to 1.79,the sustainability index of this system also experienced the slow downward trend,from 0.71 to 0.54,always less than 1,indicating that the agriculture in Hunan Province is the high consumption-driven ecosystem in general,with obvious features of extensive development.
