The calibration function for surface wave magnitude of DK1 seismograph is deduced by using least squares method of error theory based on the records of DK1 seismograph from 1987 to 1993 and the MS magnitude define...The calibration function for surface wave magnitude of DK1 seismograph is deduced by using least squares method of error theory based on the records of DK1 seismograph from 1987 to 1993 and the MS magnitude defined by International Seismological Center (ISC) as basic standard, which takes the form σ DK1 ( Δ )=(1.66±0.034)lg( Δ )+(3.2±0.11) (10° ≤ Δ ≤ 130°, T =8～20 s) From its physical essence, the calibration function for estimating surface wave magnitude by DK1 seismograph can be also deduced by means of the wave propagation theory in layer media, if the dispersion of seismic wave, absorption of media and the effect of the linear filter consisting of earth media and DK1 seismographs on the amplitudes and periods of surface wave are taken into account and it is also assumed that the maximum amplitude is response to Airy?s phase, which takes the form σ DK1 ( Δ )=1.661lg( Δ )+3.3 (10°≤ Δ ≤170°) No correction value is needed when using the calibration function deduced in this paper. Examination on surface wave magnitude of 315 events by 36 prompt earthquake stations and DK1 prompt network shows there exits no systematical error between surface magnitudes of MS (DK1) and MS (ISC) given by ISC and the average error is approximately zero.展开更多
Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. T...Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. This experimental method needn＇t special experiment equipments. Experiment＇s dynamic repeatability is good. So wrist force sensor＇s dynamic performance is suitable to be calibrated by negative step response method. A new correlation wavelet transfer method is studied. By wavelet transfer method, the signal is decomposed into two dimensional spaces of time-frequency. So the problem of negative step exciting energy concentrating in the low frequency band is solved. Correlation wavelet transfer doesn＇t require that wavelet primary function be orthogonal and needn＇t wavelet reconstruction. So analyzing efficiency is high. An experimental bench is designed and manufactured to load the wrist force sensor orthogonal excitation force/moment. A piezoelectric force sensor is used to setup soft trigger and calculate the value of negative step excitation. A wrist force sensor is calibrated. The pulse response function is calculated after negative step excitation and step response have been transformed to positive step excitation and step response. The pulse response function is transferred to frequency response function. The wrist force sensor＇s dynamic characteristics are identified by the frequency response function.展开更多
文摘The calibration function for surface wave magnitude of DK1 seismograph is deduced by using least squares method of error theory based on the records of DK1 seismograph from 1987 to 1993 and the MS magnitude defined by International Seismological Center (ISC) as basic standard, which takes the form σ DK1 ( Δ )=(1.66±0.034)lg( Δ )+(3.2±0.11) (10° ≤ Δ ≤ 130°, T =8～20 s) From its physical essence, the calibration function for estimating surface wave magnitude by DK1 seismograph can be also deduced by means of the wave propagation theory in layer media, if the dispersion of seismic wave, absorption of media and the effect of the linear filter consisting of earth media and DK1 seismographs on the amplitudes and periods of surface wave are taken into account and it is also assumed that the maximum amplitude is response to Airy?s phase, which takes the form σ DK1 ( Δ )=1.661lg( Δ )+3.3 (10°≤ Δ ≤170°) No correction value is needed when using the calibration function deduced in this paper. Examination on surface wave magnitude of 315 events by 36 prompt earthquake stations and DK1 prompt network shows there exits no systematical error between surface magnitudes of MS (DK1) and MS (ISC) given by ISC and the average error is approximately zero.
基金National Hi-tech Research and Development Program of China(863 Program,No.2001AA42330).
文摘Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. This experimental method needn＇t special experiment equipments. Experiment＇s dynamic repeatability is good. So wrist force sensor＇s dynamic performance is suitable to be calibrated by negative step response method. A new correlation wavelet transfer method is studied. By wavelet transfer method, the signal is decomposed into two dimensional spaces of time-frequency. So the problem of negative step exciting energy concentrating in the low frequency band is solved. Correlation wavelet transfer doesn＇t require that wavelet primary function be orthogonal and needn＇t wavelet reconstruction. So analyzing efficiency is high. An experimental bench is designed and manufactured to load the wrist force sensor orthogonal excitation force/moment. A piezoelectric force sensor is used to setup soft trigger and calculate the value of negative step excitation. A wrist force sensor is calibrated. The pulse response function is calculated after negative step excitation and step response have been transformed to positive step excitation and step response. The pulse response function is transferred to frequency response function. The wrist force sensor＇s dynamic characteristics are identified by the frequency response function.
