地面核磁共振(surface nuclear magnetic resonance,SNMR)技术是一种可直接定性定量探测地下水的非侵害式地球物理方法,已广泛应用于资源勘探、地质灾害预警和环境检测等方面.但在实际应用中,复杂的环境噪声导致微弱的SNMR信号常常被淹没,很难获取有效的SNMR信号.针对这一问题,本文提出了 一种基于差分结构的SNMR数据噪声压制技术,采用两个接收线圈等距设置在发射线圈上下位置.这种分布可以实时抵消大部分环境噪声以及消除收发线圈耦合影响.理论建模和仿真结果验证了新方法能够有效压制噪声,并可靠获取到早期自由感应衰减(free induction decay,FID)信号.
Noise Suppression Technique of Surface Nuclear Magnetic Resonance Data Based on Differential Structure
Surface nuclear magnetic resonance(SNMR)emerges as a non-invasive geophysical method with widespread applications in the qualitative and quantitative detection of groundwater.Its utility extends to resource exploration,geological disaster warning,and environmental monitoring.However,the practical implementation of this method encounters challenges as weak SNMR signals often contend with the pervasive noise in complex environments,hampering effective signal acquisition.In response to this issue,we propose a novel SNMR data noise suppression technique based on a differential structure.This method involves the strategic placement of two receiving coils equidistantly above and below the transmitting coil.This configuration can cancel out a significant portion of ambient noise and mitigates the effects of transceiver coil coupling in real time.Numerical experiments verify that the new method can achieve noise suppression and the reliable acquisition of free induction decay(FID)signals.
surface nuclear magnetic resonancenoise suppressionFID signaleliminates transceiver coil coupling
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维普
