| 摘要 |
Net magnetic flux trapped in an NMR high temperature superconducting RF probe coil magnetically coupled with a main excitation DC magnetic field of an NMR device of which the probe is a part is reduced by moving the probe coil relative to the main magnetic field axis. There is a resulting interaction betweeen the moving probe coil and the main excitation DC magnetic field to induce a current in the probe coil. The induced current reduces the net magnetic flux trapped in the probe coil. The probe coil is moved so the induced current is an AC current having an envelope with decreasing amplitude as a function of time. An electromechanical drive, produced by a magnetic field or an electrostatic field or a piezoelectric transducer attached to a substrate carrying the probe coil, provides oscillatory movement of the probe coil. |
