We consider two two-level atoms, interacting with two independent dissipative cavities, each of which is driven by an external source. The two cavity fields are both initially prepared in the coherent states, and the ...We consider two two-level atoms, interacting with two independent dissipative cavities, each of which is driven by an external source. The two cavity fields are both initially prepared in the coherent states, and the two two-level atoms are initially prepared in the singlet state ｜ψ^-〉 =（｜eg〉 - ｜ge〉 ） / √2. We investigate the influence of the damping constant n, the intensity of the external sources F, and the relative difference of the atomic couplings r on the entanglement between the two atoms. In the dispersive approximation, we find that the entanglement between the two atoms decreases with the time evolution, and the decreasing rate of entanglement depends on the values of F/k, k/ω, and r. For the given small values of F/k and k/ω, on the one hand, the increasing of r favors entanglement decreasing of the atomic system, on the other hand, when r → 1 the entanglement decreasing becomes slower. With the increasing of the value of k/ω, the influence of r on the decreasing rate of entanglement becomes smaller, and gradually disappears for the big value of k/ω.展开更多
When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fie...When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system： photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the enviroment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields.展开更多
Non-thermal plasma at atmosphere was generated through glidarc discharge driven by magnetic field and observed by using a high speed charge coupled device （CCD） and photo multiplier tube （PMT）. The arc diameter pr...Non-thermal plasma at atmosphere was generated through glidarc discharge driven by magnetic field and observed by using a high speed charge coupled device （CCD） and photo multiplier tube （PMT）. The arc diameter projecting in the direction of arc motion （front-viewed diameter） and the diameter projecting in the perpendicular direction of arc motion （side-viewed diameter） were measured. The effect of both the arc current and the magnetic field was analysed. The front-viewed diameter was compared with the side-viewed one. Simultaneously the electricfield intensity was measured directly and analysed by considering the effect of the external magnetic field and arc current.展开更多
In the present context of increasing social demands for natural science education,increasing people s awareness of environmental biodiversity protection,and ecological civilization lifting to the state strategy,it is ...In the present context of increasing social demands for natural science education,increasing people s awareness of environmental biodiversity protection,and ecological civilization lifting to the state strategy,it is just the time to explore a new botany field practice model.The attempt of a new task-driven model for botany field practice will greatly enhance students thinking about plants and nature,plants and environment,and plant and ecological civilization,and will inevitably enhance students initiative awareness and practical ability to protect and rationally utilize plant resources.展开更多
The gliding arc is an important approach to production of non-thermal plasma at atmospheric pressure, it can offer high-energy efficiency and high-electivity for chemical reactions. In this paper, the gliding arc driv...The gliding arc is an important approach to production of non-thermal plasma at atmospheric pressure, it can offer high-energy efficiency and high-electivity for chemical reactions. In this paper, the gliding arc driven by the transverse magnetic field is described and its velocity is measured by using a photo-multiplier. The mean velocity of the gliding arc increases with increasing magnetic induced-intensity, and its value varies from 7.8 m/s to 32 m/s.展开更多
文摘We consider two two-level atoms, interacting with two independent dissipative cavities, each of which is driven by an external source. The two cavity fields are both initially prepared in the coherent states, and the two two-level atoms are initially prepared in the singlet state ｜ψ^-〉 =（｜eg〉 - ｜ge〉 ） / √2. We investigate the influence of the damping constant n, the intensity of the external sources F, and the relative difference of the atomic couplings r on the entanglement between the two atoms. In the dispersive approximation, we find that the entanglement between the two atoms decreases with the time evolution, and the decreasing rate of entanglement depends on the values of F/k, k/ω, and r. For the given small values of F/k and k/ω, on the one hand, the increasing of r favors entanglement decreasing of the atomic system, on the other hand, when r → 1 the entanglement decreasing becomes slower. With the increasing of the value of k/ω, the influence of r on the decreasing rate of entanglement becomes smaller, and gradually disappears for the big value of k/ω.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10175029, 10375039, and 10647007, the Doctoral Education Fund of Ministry of Education, the Research Fund of Nuclear Theory Center of HIRFL of China, and the Science and Technology Foundation of Sichuan Province under Grant No. 02GY029-189
文摘When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system： photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the enviroment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields.
基金National Natural Science Foundation of China(No.10375065)Natural Science Foundation of Anhui Province(No.03045102)
文摘Non-thermal plasma at atmosphere was generated through glidarc discharge driven by magnetic field and observed by using a high speed charge coupled device （CCD） and photo multiplier tube （PMT）. The arc diameter projecting in the direction of arc motion （front-viewed diameter） and the diameter projecting in the perpendicular direction of arc motion （side-viewed diameter） were measured. The effect of both the arc current and the magnetic field was analysed. The front-viewed diameter was compared with the side-viewed one. Simultaneously the electricfield intensity was measured directly and analysed by considering the effect of the external magnetic field and arc current.
基金Supported by Special Fund for Reform of Teaching Model of Huanggang Normal University(2016CK06,2018CE42)
文摘In the present context of increasing social demands for natural science education,increasing people s awareness of environmental biodiversity protection,and ecological civilization lifting to the state strategy,it is just the time to explore a new botany field practice model.The attempt of a new task-driven model for botany field practice will greatly enhance students thinking about plants and nature,plants and environment,and plant and ecological civilization,and will inevitably enhance students initiative awareness and practical ability to protect and rationally utilize plant resources.
文摘The gliding arc is an important approach to production of non-thermal plasma at atmospheric pressure, it can offer high-energy efficiency and high-electivity for chemical reactions. In this paper, the gliding arc driven by the transverse magnetic field is described and its velocity is measured by using a photo-multiplier. The mean velocity of the gliding arc increases with increasing magnetic induced-intensity, and its value varies from 7.8 m/s to 32 m/s.
文摘文章对某多层建筑屋面区域风驱雨(wind-driven rain,WDR)开展实测,结合3类典型降雨事件的分析,揭示大气湍流特征以及风速、风向对雨滴的影响特性,并针对突出屋面建筑,实测分析立面WDR分布特性,量化国际标准化组织(International Organization for Standardization,ISO)半经验模型对突出屋面建筑WDR预测的偏差。结果表明,在3类降雨事件中,湍流度、阵风因子和湍流积分尺度的实测值与基于地面实测建立的公式理论值之间存在较大差异;实测的雨滴数量与标准M-P谱计算的雨滴数量差值最大为125个。在风速和雨强差异较小时,建筑立面WDR分布受来流与立面夹角的影响显著。由于ISO半经验模型是基于地面实测建立的,其对突出屋面建筑WDR的预测存在偏差,在模型适用的降雨条件下实测值约为ISO预测值的2倍。
