Following Jaynes-Cummings model,the evolution of the field entropy in the system of a two-level atom interacting with the single mode coherent field is investigated under rotating-wave approximation.The typical case &...Following Jaynes-Cummings model,the evolution of the field entropy in the system of a two-level atom interacting with the single mode coherent field is investigated under rotating-wave approximation.The typical case "the field frequency variance with time in the form of sine ω=ω0+usin(wt) has been considered.The influences of the amplitude and angle frequency of the field frequency variance on entropy evolution of the field are discussed by numerical calculations.Calculation results indicate that the field frequency variance influences violently the behavior of field entropy evolution;the larger the amplitude of the field frequency variance is,the stronger the influence of the field frequency variance on the time evolution of field entropy is.展开更多
Generalized Inversion Method has been used to estimate the spatial variation of site effects,using the digital data of SH-waves recorded by 63 stations in the Capital Circle Region of China from 2001 to 2006.We gained...Generalized Inversion Method has been used to estimate the spatial variation of site effects,using the digital data of SH-waves recorded by 63 stations in the Capital Circle Region of China from 2001 to 2006.We gained the site effects of all stations participating in the calculation.We found that the site effect of rock was stabile and about 1.0 from 1.0Hz to 10.0Hz,while the site effect of deposit was high in low frequencies,about 3 ～ 7 from 1.0Hz to 8.0Hz,and the site effect was protuberant at about 5.0Hz,then fell as the frequency increased.The result shows the shape and intensity of station site effects are mainly influenced by the lithology below the station,and possibly also by the local geological structure.展开更多
The seismic activities on the Earth can produce a disturbance of the electromagnetic field and particles in the ionosphere. The search coil magnetometer(SCM) mounted on China Seismo-Electromagnetic satellite(CSES) is ...The seismic activities on the Earth can produce a disturbance of the electromagnetic field and particles in the ionosphere. The search coil magnetometer(SCM) mounted on China Seismo-Electromagnetic satellite(CSES) is designed to measure the magnetic field fluctuation of low frequency electromagnetic waves in the frequency range of 10 Hz–20 k Hz. The SCM comprises a three-axis search coil sensor mounted on a 4.5 m boom and an electronic box inside satellite module. The sampling rate of the SCM is 51.2 k Hz and the time resolution of the power spectrum density(PSD) is 2 s. The frequency resolution is 12.5 Hz.There are three operation modes: survey, detailed survey and calibration. In the survey mode, the SCM can provide a PSD in the whole frequency range of 10 Hz–20 k Hz and wave forms in the low frequency range below 2 k Hz while in the detailed survey mode the SCM can provide both PSD and wave forms in the whole frequency range of 10 Hz–20 k Hz. The sensitivity of the SCM instrument is 5.0×10^(-4) n T Hz^(-1/2) at 10 Hz, 5.0×10^(–5) n T Hz^(-1/2) at 200 Hz, 3.4×10^(-5) n T Hz^(-1/2) at 2 k Hz and 1.1×10^(-4) n T Hz^(-1/2) at 20 k Hz. The telemetry rate is ~0.85 Mbps in the survey mode and ~3.0 Mbps in the detailed survey mode. The phase difference between three axes can be made generally with a precision of less than 1.0°. The dynamic range of the SCM instrument is over 100 d B. The orthogonality of three mechanical axes of search coil senor is better than 0.13°. The performance of SCM can satisfy the requirement of scientific objectives of CSES mission.展开更多
基金Natural Science Foundation of Fujian Province under Grant(No.2008J0217)
文摘Following Jaynes-Cummings model,the evolution of the field entropy in the system of a two-level atom interacting with the single mode coherent field is investigated under rotating-wave approximation.The typical case "the field frequency variance with time in the form of sine ω=ω0+usin(wt) has been considered.The influences of the amplitude and angle frequency of the field frequency variance on entropy evolution of the field are discussed by numerical calculations.Calculation results indicate that the field frequency variance influences violently the behavior of field entropy evolution;the larger the amplitude of the field frequency variance is,the stronger the influence of the field frequency variance on the time evolution of field entropy is.
基金sponsored by the Special Foundation of China Earthquake Administration (2007-8-26)
文摘Generalized Inversion Method has been used to estimate the spatial variation of site effects,using the digital data of SH-waves recorded by 63 stations in the Capital Circle Region of China from 2001 to 2006.We gained the site effects of all stations participating in the calculation.We found that the site effect of rock was stabile and about 1.0 from 1.0Hz to 10.0Hz,while the site effect of deposit was high in low frequencies,about 3 ～ 7 from 1.0Hz to 8.0Hz,and the site effect was protuberant at about 5.0Hz,then fell as the frequency increased.The result shows the shape and intensity of station site effects are mainly influenced by the lithology below the station,and possibly also by the local geological structure.
基金supported by the National Natural Science Foundation of China(Grant No.41431071)
文摘The seismic activities on the Earth can produce a disturbance of the electromagnetic field and particles in the ionosphere. The search coil magnetometer(SCM) mounted on China Seismo-Electromagnetic satellite(CSES) is designed to measure the magnetic field fluctuation of low frequency electromagnetic waves in the frequency range of 10 Hz–20 k Hz. The SCM comprises a three-axis search coil sensor mounted on a 4.5 m boom and an electronic box inside satellite module. The sampling rate of the SCM is 51.2 k Hz and the time resolution of the power spectrum density(PSD) is 2 s. The frequency resolution is 12.5 Hz.There are three operation modes: survey, detailed survey and calibration. In the survey mode, the SCM can provide a PSD in the whole frequency range of 10 Hz–20 k Hz and wave forms in the low frequency range below 2 k Hz while in the detailed survey mode the SCM can provide both PSD and wave forms in the whole frequency range of 10 Hz–20 k Hz. The sensitivity of the SCM instrument is 5.0×10^(-4) n T Hz^(-1/2) at 10 Hz, 5.0×10^(–5) n T Hz^(-1/2) at 200 Hz, 3.4×10^(-5) n T Hz^(-1/2) at 2 k Hz and 1.1×10^(-4) n T Hz^(-1/2) at 20 k Hz. The telemetry rate is ~0.85 Mbps in the survey mode and ~3.0 Mbps in the detailed survey mode. The phase difference between three axes can be made generally with a precision of less than 1.0°. The dynamic range of the SCM instrument is over 100 d B. The orthogonality of three mechanical axes of search coil senor is better than 0.13°. The performance of SCM can satisfy the requirement of scientific objectives of CSES mission.
