目的:探索间歇性θ短阵脉冲刺激(iTBS)对脑卒中后中重度运动功能障碍患者的即刻影响机制。方法:于2020年8月—2021年3月在复旦大学附属华山医院康复医学科门诊或病房招募脑卒中患者10例,随机分为iTBS组和安慰刺激组,i TBS组接受单次患...目的:探索间歇性θ短阵脉冲刺激(iTBS)对脑卒中后中重度运动功能障碍患者的即刻影响机制。方法:于2020年8月—2021年3月在复旦大学附属华山医院康复医学科门诊或病房招募脑卒中患者10例,随机分为iTBS组和安慰刺激组,i TBS组接受单次患侧初级运动皮层区(primary motor cortex,M1)的iTBS干预,安慰刺激组接受单次患侧M1的安慰刺激干预。干预前后对所有患者进行神经电生理评估和近红外脑功能检测。结果:与安慰刺激组相比,i TBS刺激组干预后功能连接强度在患侧M1区-健侧初级躯体感觉皮层区(primary somatosensory cortex,S1)和患侧M1区-健侧辅助运动皮层区(pre-motor and supplementary motor cortex,SMA)较干预前显著性升高(P<0.05)。然而,双侧M1区的MEP波幅并未发生显著性变化(P>0.05)。结论:针对脑卒中后中重度运动功能障碍患者,单次iTBS刺激可引起大脑发生即刻的神经可塑性改变,但未能引起大脑结构或功能的显著性变化。展开更多
We demonstrate a two-component detection of a coherent population trapping(CPT)resonance based on virtually imaged phased array(VIPA).After passing through a VIPA,the two coupling lights with different frequencies in ...We demonstrate a two-component detection of a coherent population trapping(CPT)resonance based on virtually imaged phased array(VIPA).After passing through a VIPA,the two coupling lights with different frequencies in the CPT experiment are separated in space and detected individually.The asymmetric lineshape is observed experimentally in the CPT signal for each component,and the comparison with the conventional detection is presented.The shift of the CPT resonant frequency is studied with both the two-component and one-component detections.Our scheme provides a convenient way to further study the CPT phenomenon for each frequency component.展开更多
We have investigated the dispersive properties of excited-doublet four-level atoms interacting with a weak probe field and an intense coupling laser field. We have derived an analytical expression of the dispersion re...We have investigated the dispersive properties of excited-doublet four-level atoms interacting with a weak probe field and an intense coupling laser field. We have derived an analytical expression of the dispersion relation for a general excited-doublet four-level atomic system subject to a one-photon detuning. The numerical results demonstrate that for a typical rubidium D1 line configuration, due to the unequal dipole moments for the transitions of each ground state to double excited states, generally there exists no exact dark state in the system. Close to the two-photon resonance, the probe light can be absorbed or gained and propagate in the so-called superluminal form. This system may be used as an optical switch.展开更多
This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically indu...This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically induced transparency is changed to electromagnetically induced absorption and the absorptive spectral line can be very narrow. This ultranarrow spectral line has potential applications to the microwave atomic frequency standard and the measurement of very weak magnetic field.展开更多
High contrast transparent Ramsey fringes are observed using double microwave pulses interaction with the prepared atomic coherent state in a warm STRb vapor with mixture buffer gases in a closed cell. The Ramsey fring...High contrast transparent Ramsey fringes are observed using double microwave pulses interaction with the prepared atomic coherent state in a warm STRb vapor with mixture buffer gases in a closed cell. The Ramsey fringes are generated by the pulsed technique, a strong coupling light pulse and a weak signal light pulse are applied to prepare the atomic coherent state, followed by the application of double microwave pulses to interact with the atomic coherent state. Afterwards, the light pulses are applied again with weaker intensity and detecting the signal transmission is delected. The central line of the transparent Ramsey fringes has narrow linewidth of 125 Hz and high contrast of 21%. The light shift is dramatically reduced since the interrogating process is not involved the light field, and the cavity pulling effect is negligible due to the low Q requirement, which is promising for building small, compact, and stable atomic clocks.展开更多
We report the recent progress of our pulsed optically pumped（POP） vapor cell rubidium clock with dispersive detection.A new compact physics package is made.A rubidium cell with a high precision buffer gases mixing r...We report the recent progress of our pulsed optically pumped（POP） vapor cell rubidium clock with dispersive detection.A new compact physics package is made.A rubidium cell with a high precision buffer gases mixing ratio is obtained,and the temperature controlling system is renovated to reduce fractional frequency sensitivity to temperature variation.The resolution of the servo control voltage is also optimized.With these improvements,a clock frequency stability of 3.53×10-13 at 1s is obtained,and a fractional frequency stability of 4.91×10-15 is achieved at an average time of τ=2000 s.展开更多
文摘目的:探索间歇性θ短阵脉冲刺激(iTBS)对脑卒中后中重度运动功能障碍患者的即刻影响机制。方法:于2020年8月—2021年3月在复旦大学附属华山医院康复医学科门诊或病房招募脑卒中患者10例,随机分为iTBS组和安慰刺激组,i TBS组接受单次患侧初级运动皮层区(primary motor cortex,M1)的iTBS干预,安慰刺激组接受单次患侧M1的安慰刺激干预。干预前后对所有患者进行神经电生理评估和近红外脑功能检测。结果:与安慰刺激组相比,i TBS刺激组干预后功能连接强度在患侧M1区-健侧初级躯体感觉皮层区(primary somatosensory cortex,S1)和患侧M1区-健侧辅助运动皮层区(pre-motor and supplementary motor cortex,SMA)较干预前显著性升高(P<0.05)。然而,双侧M1区的MEP波幅并未发生显著性变化(P>0.05)。结论:针对脑卒中后中重度运动功能障碍患者,单次iTBS刺激可引起大脑发生即刻的神经可塑性改变,但未能引起大脑结构或功能的显著性变化。
基金supported by the National Natural Science Foundation of China(Nos.12005187 and 91536220)。
文摘We demonstrate a two-component detection of a coherent population trapping(CPT)resonance based on virtually imaged phased array(VIPA).After passing through a VIPA,the two coupling lights with different frequencies in the CPT experiment are separated in space and detected individually.The asymmetric lineshape is observed experimentally in the CPT signal for each component,and the comparison with the conventional detection is presented.The shift of the CPT resonant frequency is studied with both the two-component and one-component detections.Our scheme provides a convenient way to further study the CPT phenomenon for each frequency component.
基金supported by the Knowledge Innovation Program (KIP) of the Chinese Academy of Sciences (Grant No KGCX3-SYW-405)the National Fundamental Research Program of China (Grant Nos 2005CB724507 and 2006CB921202)
文摘We have investigated the dispersive properties of excited-doublet four-level atoms interacting with a weak probe field and an intense coupling laser field. We have derived an analytical expression of the dispersion relation for a general excited-doublet four-level atomic system subject to a one-photon detuning. The numerical results demonstrate that for a typical rubidium D1 line configuration, due to the unequal dipole moments for the transitions of each ground state to double excited states, generally there exists no exact dark state in the system. Close to the two-photon resonance, the probe light can be absorbed or gained and propagate in the so-called superluminal form. This system may be used as an optical switch.
基金Project supported by the Knowledge Innovation Program (KIP) of the Chinese Academy of Sciences(Grant No KGCX3-SYW-405)the State Key Development Program for Basic Research of China(Grant Nos 2005CB724507 and 2006CB921202)
文摘This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically induced transparency is changed to electromagnetically induced absorption and the absorptive spectral line can be very narrow. This ultranarrow spectral line has potential applications to the microwave atomic frequency standard and the measurement of very weak magnetic field.
基金supported by the Major State Basic Research Development Program of China under Grant No.2005CB724507
文摘High contrast transparent Ramsey fringes are observed using double microwave pulses interaction with the prepared atomic coherent state in a warm STRb vapor with mixture buffer gases in a closed cell. The Ramsey fringes are generated by the pulsed technique, a strong coupling light pulse and a weak signal light pulse are applied to prepare the atomic coherent state, followed by the application of double microwave pulses to interact with the atomic coherent state. Afterwards, the light pulses are applied again with weaker intensity and detecting the signal transmission is delected. The central line of the transparent Ramsey fringes has narrow linewidth of 125 Hz and high contrast of 21%. The light shift is dramatically reduced since the interrogating process is not involved the light field, and the cavity pulling effect is negligible due to the low Q requirement, which is promising for building small, compact, and stable atomic clocks.
基金supported by the National Natural Science Foundation of China under Grant Nos.91536220 and 11504393
文摘We report the recent progress of our pulsed optically pumped（POP） vapor cell rubidium clock with dispersive detection.A new compact physics package is made.A rubidium cell with a high precision buffer gases mixing ratio is obtained,and the temperature controlling system is renovated to reduce fractional frequency sensitivity to temperature variation.The resolution of the servo control voltage is also optimized.With these improvements,a clock frequency stability of 3.53×10-13 at 1s is obtained,and a fractional frequency stability of 4.91×10-15 is achieved at an average time of τ=2000 s.
