Based on seismic source spectrum solution by multi-station and multi-event coda method, applying Brune seismic source model, we have got the source factors and spectra of 48 small earthquakes occurred before and after...Based on seismic source spectrum solution by multi-station and multi-event coda method, applying Brune seismic source model, we have got the source factors and spectra of 48 small earthquakes occurred before and after the Douhe earthquake of October 6 in 1995. The seismic moments, corner frequencies and stress drops are estimated from the Spectra, and their corrclation and variation with time before and after the Douhe ear-thquake are discussed. The results indicate that the source factors show good stability, their peak frequencies and variation with frequencyappear quite similar. Some events with higher stress drops occurred about one year before the Douhe ertquake.Taking into the account that the Stress drop is calculated from seismic moment and frequency, as well as the correlation betwen them, we emphasis that the higher stress drop mentioned here just implies the higher corner frequency than the normal value.展开更多
The particle motion equation for a Radio Frequency（RF） quadrupole is derived. The motion equation shows that the general transform matrix of a RF quadrupole with length less than or equal to 0.5βλ（β is the relat...The particle motion equation for a Radio Frequency（RF） quadrupole is derived. The motion equation shows that the general transform matrix of a RF quadrupole with length less than or equal to 0.5βλ（β is the relativistic velocity of particles and λ is wavelength of radio frequency electromagnetic field） can describe the particle motion in an arbitrarily long RF quadrupole. By iterative integration, the general transform matrix of a discrete RF quadrupole is derived from the motion equation. The transform matrix is in form of a power series of focusing parameter B. It shows that for length less than βλ, the series up to the 2ndorder of B agrees well with the direct integration results for B up to 30, while for length less than 0.5βλ, the series up to 1storder is already a good approximation of the real solution for B less than 30. The formula of the transform matrix can be integrated into linac or beam line design code to deal with the focusing of discrete RF quadrupoles.展开更多
文摘Based on seismic source spectrum solution by multi-station and multi-event coda method, applying Brune seismic source model, we have got the source factors and spectra of 48 small earthquakes occurred before and after the Douhe earthquake of October 6 in 1995. The seismic moments, corner frequencies and stress drops are estimated from the Spectra, and their corrclation and variation with time before and after the Douhe ear-thquake are discussed. The results indicate that the source factors show good stability, their peak frequencies and variation with frequencyappear quite similar. Some events with higher stress drops occurred about one year before the Douhe ertquake.Taking into the account that the Stress drop is calculated from seismic moment and frequency, as well as the correlation betwen them, we emphasis that the higher stress drop mentioned here just implies the higher corner frequency than the normal value.
基金Supported by National Natural Science Foundation of China(11375122,11511140277)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA03020705)
文摘The particle motion equation for a Radio Frequency（RF） quadrupole is derived. The motion equation shows that the general transform matrix of a RF quadrupole with length less than or equal to 0.5βλ（β is the relativistic velocity of particles and λ is wavelength of radio frequency electromagnetic field） can describe the particle motion in an arbitrarily long RF quadrupole. By iterative integration, the general transform matrix of a discrete RF quadrupole is derived from the motion equation. The transform matrix is in form of a power series of focusing parameter B. It shows that for length less than βλ, the series up to the 2ndorder of B agrees well with the direct integration results for B up to 30, while for length less than 0.5βλ, the series up to 1storder is already a good approximation of the real solution for B less than 30. The formula of the transform matrix can be integrated into linac or beam line design code to deal with the focusing of discrete RF quadrupoles.
