The technique of surface magnetic resonance(SNMR)has been widely used for hydrological investigations by the advantage of locating the bulk of aquifer directly.However,the low signal-to-noise ratio(SNR)is one of the most difficult problems.For the purpose of improving SNR,a new approach using pre-polarization(PP)applying by a direct current(DC)in adiabatic pulses has been introduced to improve the excitation volume and thus the signal amplitude both in shallow and deep depth,instead of using alternating current(AC)field in the traditional way.To substantiate the effectiveness of this method,we conduct the numerical simulations of PP adiabatic pulses using in SNMR.We expect this development to open up new applications for SNMR technology,especially in high-noise level places.
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