The femtosecond pulse shaping technique has been shown to be an effective method to control the multi-photon absorption by the light–matter interaction. Previous studies mainly focused on the quantum coherent control...The femtosecond pulse shaping technique has been shown to be an effective method to control the multi-photon absorption by the light–matter interaction. Previous studies mainly focused on the quantum coherent control of the multi-photon absorption by the phase, amplitude and polarization modulation, but the coherent features of the multi-photon absorption depending on the energy level structure, the laser spectrum bandwidth and laser central frequency still lack in-depth systematic research. In this work, we further explore the coherent features of the resonance-mediated two-photon absorption in a rubidium atom by varying the energy level structure, spectrum bandwidth and central frequency of the femtosecond laser field. The theoretical results show that the change of the intermediate state detuning can effectively influence the enhancement of the near-resonant part, which further affects the transform-limited （TL）-normalized final state population maximum. Moreover, as the laser spectrum bandwidth increases, the TL-normalized final state population maximum can be effectively enhanced due to the increase of the enhancement in the near-resonant part, but the TL-normalized final state population maximum is constant by varying the laser central frequency. These studies can provide a clear physical picture for understanding the coherent features of the resonance-mediated two-photon absorption, and can also provide a theoretical guidance for the future applications.展开更多
Objective To explore the effects of enhanced external counterpulsation(EECP)on the serum level of C-reactive protein and endothelin-1 in patients with cerebral ischemic stroke,to provide clinical evidence for the trea...Objective To explore the effects of enhanced external counterpulsation(EECP)on the serum level of C-reactive protein and endothelin-1 in patients with cerebral ischemic stroke,to provide clinical evidence for the treatment and secondary prevention of patients with serebral ischemic stroke.Methods Total 187 patients with ischemic stroke and enrolled measure the serum level展开更多
An extreme solar cosmic ray event broke out on 2005 January 20. Not only is it the most intensive solar energetic particle （SEP） event, with 〉100 MeV particles measured by GOES satellite since 1986, but it has been...An extreme solar cosmic ray event broke out on 2005 January 20. Not only is it the most intensive solar energetic particle （SEP） event, with 〉100 MeV particles measured by GOES satellite since 1986, but it has been the largest ground level enhancement （GLE） event recorded by the ground-based neutron monitors since 1956. This work presents the solar proton spectra for this event with data obtained by GOES in multiple energy channels. These spectra are well fitted by a modified power-law function. The spectral index of around -1 indicates that the January 20 event has a hard energy spectrum. Possible mechanisms for the acceleration of relativistic protons are discussed.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 51132004,11474096 and 11604199the Science and Technology Commission of Shanghai Municipality under Grant No 14JC1401500the Higher Education Key Program of He'nan Province under Grant Nos 17A140025 and 16A140030
文摘The femtosecond pulse shaping technique has been shown to be an effective method to control the multi-photon absorption by the light–matter interaction. Previous studies mainly focused on the quantum coherent control of the multi-photon absorption by the phase, amplitude and polarization modulation, but the coherent features of the multi-photon absorption depending on the energy level structure, the laser spectrum bandwidth and laser central frequency still lack in-depth systematic research. In this work, we further explore the coherent features of the resonance-mediated two-photon absorption in a rubidium atom by varying the energy level structure, spectrum bandwidth and central frequency of the femtosecond laser field. The theoretical results show that the change of the intermediate state detuning can effectively influence the enhancement of the near-resonant part, which further affects the transform-limited （TL）-normalized final state population maximum. Moreover, as the laser spectrum bandwidth increases, the TL-normalized final state population maximum can be effectively enhanced due to the increase of the enhancement in the near-resonant part, but the TL-normalized final state population maximum is constant by varying the laser central frequency. These studies can provide a clear physical picture for understanding the coherent features of the resonance-mediated two-photon absorption, and can also provide a theoretical guidance for the future applications.
文摘Objective To explore the effects of enhanced external counterpulsation(EECP)on the serum level of C-reactive protein and endothelin-1 in patients with cerebral ischemic stroke,to provide clinical evidence for the treatment and secondary prevention of patients with serebral ischemic stroke.Methods Total 187 patients with ischemic stroke and enrolled measure the serum level
文摘An extreme solar cosmic ray event broke out on 2005 January 20. Not only is it the most intensive solar energetic particle （SEP） event, with 〉100 MeV particles measured by GOES satellite since 1986, but it has been the largest ground level enhancement （GLE） event recorded by the ground-based neutron monitors since 1956. This work presents the solar proton spectra for this event with data obtained by GOES in multiple energy channels. These spectra are well fitted by a modified power-law function. The spectral index of around -1 indicates that the January 20 event has a hard energy spectrum. Possible mechanisms for the acceleration of relativistic protons are discussed.
