Based on the telluric field data from a Sino-France cooperation station and analysis of the linear characteristic of telluric field polarization, this paper puts forward a new method, called vertical projection to the...Based on the telluric field data from a Sino-France cooperation station and analysis of the linear characteristic of telluric field polarization, this paper puts forward a new method, called vertical projection to the polarization, to recognize seismic electrical anomaly from observation background. Through careful analysis of polarization variation in different time intervals, it is determined that the best time interval for the regression of polarization is 24 h. Telluric observational data from two earthquakes, one is Yongdeng M_s=5.8 earthquake on July 22, 1995, the other is west Tianzhu M_s=5.4 earthquake on June 1, 1996, are processed by this new method, it is interesting to discover that abnormal electrical signals appeared 28 days and respectively. The limit condition of using this method is discussed finally.展开更多
Observing a telluric standard star for correcting the telluric absorption lines of spectrum will take a significant amount of precious telescope time,especially in the long-term spectral monitoring project.Beyond that...Observing a telluric standard star for correcting the telluric absorption lines of spectrum will take a significant amount of precious telescope time,especially in the long-term spectral monitoring project.Beyond that,it is difficult to select a suitable telluric standard star near in both time and airmass to the scientific object.In this paper,we present a method of correcting the telluric absorption lines by combining the advantages of long slit spectroscopy.By rotating the slit,we observed the scientific object and a nearby comparison star in one exposure,so that the spectra of both objects should have the same telluric transmission spectrum.The telluric transmission spectrum was constructed by dividing the observed spectrum of the comparison star by its stellar template,and was used to correct the telluric absorption lines of the scientific object.Using the long slit spectrograph of the Lijiang 2.4-meter telescope,we designed a long-term spectroscopic observation strategy,and finished a four-year spectroscopic monitoring for a pair of objects(an active galactic nucleus and a non-varying comparison star).We applied this method to correct the telluric absorption lines of the long-term monitored spectra by the Lijiang 2.4-meter telescope,and investigated the variation of the telluric absorptions at Lijiang Observatory.We found that the telluric absorption transparency is mainly modulated by the seasonal variability of the relative humidity,airmass and seeing.Using the scatter of the [O Ⅲ] λ5007 fluxes emitted from the narrow-line region of active galactic nuclei as an indicator,we found that the correction accuracy of the telluric absorption lines is 1%.展开更多
The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured re...The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured results of some key modules in transmitter are presented, and some outdoor experimental tests have been carried out, which shows that the completed prototype of transmitter can generate a continuous sine current with frequency up to 35.33 k Hz, peak-to-peak amplitude up to 40 A, and realize a reliable transmitting mode with multi-frequency and high-current. The transmitter has a wide operating band, large magnetic moment and high waveform fidelity, and can meet the requirements of shallow geological exploration with high-resolution.展开更多
文摘Based on the telluric field data from a Sino-France cooperation station and analysis of the linear characteristic of telluric field polarization, this paper puts forward a new method, called vertical projection to the polarization, to recognize seismic electrical anomaly from observation background. Through careful analysis of polarization variation in different time intervals, it is determined that the best time interval for the regression of polarization is 24 h. Telluric observational data from two earthquakes, one is Yongdeng M_s=5.8 earthquake on July 22, 1995, the other is west Tianzhu M_s=5.4 earthquake on June 1, 1996, are processed by this new method, it is interesting to discover that abnormal electrical signals appeared 28 days and respectively. The limit condition of using this method is discussed finally.
基金supported by the National Natural Science Foundation of China(NSFCGrant Nos.11991051,12073068,11703077,and 11803087)+2 种基金financial support from the Yunnan Province Foundation(202001AT070069)the Light of West China Program provided by Chinese Academy of Sciences(Y7XB016001)financial support from the Light of West China Program provided by Chinese Academy of Sciences(Y8XB018001)。
文摘Observing a telluric standard star for correcting the telluric absorption lines of spectrum will take a significant amount of precious telescope time,especially in the long-term spectral monitoring project.Beyond that,it is difficult to select a suitable telluric standard star near in both time and airmass to the scientific object.In this paper,we present a method of correcting the telluric absorption lines by combining the advantages of long slit spectroscopy.By rotating the slit,we observed the scientific object and a nearby comparison star in one exposure,so that the spectra of both objects should have the same telluric transmission spectrum.The telluric transmission spectrum was constructed by dividing the observed spectrum of the comparison star by its stellar template,and was used to correct the telluric absorption lines of the scientific object.Using the long slit spectrograph of the Lijiang 2.4-meter telescope,we designed a long-term spectroscopic observation strategy,and finished a four-year spectroscopic monitoring for a pair of objects(an active galactic nucleus and a non-varying comparison star).We applied this method to correct the telluric absorption lines of the long-term monitored spectra by the Lijiang 2.4-meter telescope,and investigated the variation of the telluric absorptions at Lijiang Observatory.We found that the telluric absorption transparency is mainly modulated by the seasonal variability of the relative humidity,airmass and seeing.Using the scatter of the [O Ⅲ] λ5007 fluxes emitted from the narrow-line region of active galactic nuclei as an indicator,we found that the correction accuracy of the telluric absorption lines is 1%.
文摘The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured results of some key modules in transmitter are presented, and some outdoor experimental tests have been carried out, which shows that the completed prototype of transmitter can generate a continuous sine current with frequency up to 35.33 k Hz, peak-to-peak amplitude up to 40 A, and realize a reliable transmitting mode with multi-frequency and high-current. The transmitter has a wide operating band, large magnetic moment and high waveform fidelity, and can meet the requirements of shallow geological exploration with high-resolution.
