广州地磁台转换函数的长期变化和季节变化

本文全面系统地研究了1960——1987年广州地磁台转换函数的变化.结果表明:(1)季节变化的特点是夏季幅度大,冬季幅度小,具有12和6个月的主要周期成份;长期变化则表现以每年0.0025的速率下降.转换函数 B 的长期变化和季节变化不明显;(2)由转换函数 A,B 求出的帕金森矢量的方向明显地受海洋的影响,反映了海洋效应;(3)转换函数 A,B 的逐月值与地磁活动相关,而年均值与地磁活动无关.A 的年均值无明显的11年或22年周期.长期变化可能主要受地球内部电性结构的影响. 

RECORDING OF WAVEFORMS AND LOCALIZATION OF ACOUSTIC EMISSION EVENTS PRODUCED IN ROCK SAMPLES

We have made the data collection and analysis system for recording microcracks in rock to study the three dimensional pattern of fracture and the dynamic properties of rock during pressurization. This system,with 8 channel data detection, records in real-time, from the initial microcracks to the final vibration waveform excited by the master fracture. The detected data are recorded by digital theharddiskofan IBM personal computerfor 286,386 personal computer) as well as transmitted to the disk. The sampling rate for each channel is 10 MHz.Collecting every acoustic emission events in the loaded rock sample with 8 channels by this system, mathematically modelling the AE event travel time, and taking the coordinates of the AE event hypocenter and the three components of P wave velocity as unknown parameters, we set up a set of residual equations for joint inversion, so that the three dimensional localization of AE event hypocenters can be completed under variable velocities, which will lay foundations for the research on rock fracture clearly.