County-level town is important space carrier of China's urbanization and the emphasis and key of strategic distribution for urbanization. Backwardness of county-level towns limits nearby transfer of surplus labor....County-level town is important space carrier of China's urbanization and the emphasis and key of strategic distribution for urbanization. Backwardness of county-level towns limits nearby transfer of surplus labor. To promote development of county-level towns,on the basis of classifying county-level towns,this paper analyzed motive and resistance factors of evolution of different county-level towns using historical data collection and statistical method,comparative approach,typical case study method,and studied development path for different county-level towns. From analysis,it reached the conclusion that industry exerts the most direct and fundamental influence on development of county-level towns,while the industrial development in county-level towns must base on their actual conditions. The county-level towns are not isolated,and their development should be established within the framework of national policy environment and superior and subordinate town system.展开更多
We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approac...We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.展开更多
We utilize an electromagnetically induced transparency(EIT) of a three-level cascade system involving Rydberg state in a room-temperature cell, formed with a cesium 6 S_(1/2)–6 P_(3/2)–66 S_(1/2) scheme, to investig...We utilize an electromagnetically induced transparency(EIT) of a three-level cascade system involving Rydberg state in a room-temperature cell, formed with a cesium 6 S_(1/2)–6 P_(3/2)–66 S_(1/2) scheme, to investigate the Autler–Townes(AT)splitting resulting from a 15.21-GHz radio-frequency(RF) field that couples the |66 S_(1/2) → |65 P_(1/2) Rydberg transition.The radio-frequency electric field induced AT splitting, γAT, is defined as the peak-to-peak distance of an EIT-AT spectrum.The dependence of AT splitting γAT on the probe and coupling Rabi frequency, ?_p and ?_c, is investigated. It is found that the EIT-AT splitting strongly depends on the EIT linewidth that is related to the probe and coupling Rabi frequency in a weak RF-field regime. Using a narrow linewidth EIT spectrum would decrease the uncertainty of the RF field measurements.This work provides new experimental evidence for the theoretical framework in [J. Appl. Phys. 121, 233106(2017)].展开更多
基金Supported by Key Project of National Social Science Foundation(11&ZD009)
文摘County-level town is important space carrier of China's urbanization and the emphasis and key of strategic distribution for urbanization. Backwardness of county-level towns limits nearby transfer of surplus labor. To promote development of county-level towns,on the basis of classifying county-level towns,this paper analyzed motive and resistance factors of evolution of different county-level towns using historical data collection and statistical method,comparative approach,typical case study method,and studied development path for different county-level towns. From analysis,it reached the conclusion that industry exerts the most direct and fundamental influence on development of county-level towns,while the industrial development in county-level towns must base on their actual conditions. The county-level towns are not isolated,and their development should be established within the framework of national policy environment and superior and subordinate town system.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41104094 and 11174119)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20114324120002)+1 种基金the Research Foundation of Education Bureau of Hunan Province,China(Grant No.12C0370)the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the National Natural Science Foundation of China(Grant Nos.61475090,61675123,61775124,and 11804202)+1 种基金the State Key Program of National Natural Science of China(Grant Nos.11434007 and61835007)the Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(Grant No.IRT13076)
文摘We utilize an electromagnetically induced transparency(EIT) of a three-level cascade system involving Rydberg state in a room-temperature cell, formed with a cesium 6 S_(1/2)–6 P_(3/2)–66 S_(1/2) scheme, to investigate the Autler–Townes(AT)splitting resulting from a 15.21-GHz radio-frequency(RF) field that couples the |66 S_(1/2) → |65 P_(1/2) Rydberg transition.The radio-frequency electric field induced AT splitting, γAT, is defined as the peak-to-peak distance of an EIT-AT spectrum.The dependence of AT splitting γAT on the probe and coupling Rabi frequency, ?_p and ?_c, is investigated. It is found that the EIT-AT splitting strongly depends on the EIT linewidth that is related to the probe and coupling Rabi frequency in a weak RF-field regime. Using a narrow linewidth EIT spectrum would decrease the uncertainty of the RF field measurements.This work provides new experimental evidence for the theoretical framework in [J. Appl. Phys. 121, 233106(2017)].
