In this work, optimal control theory was used to design efficient excitation schemes in highly conductive materials, where both the radio frequency field strength and phase vary as a function of penetration depth. A pulse was designed to achieve phase alignment between signals at different depths within the conductor and thus to obtain higher signals from that region. In addition, an efficient suppression pulse was designed by insuring mutual suppression between the signals from various depths in the sample. The performance of the new approach was demonstrated experimentally for a bulk lithium sample for the excitation problem and for a biphasic metal/liquid sample for the selective suppression pulse.

中文翻译：

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用于在导电介质中激发和抑制NMR信号的最佳控制RF脉冲

在这项工作中，最优控制理论被用于设计高导电材料中的有效激励方案，其中射频场强和相位都随穿透深度而变化。设计了一个脉冲，以实现导体内不同深度的信号之间的相位对准，从而从该区域获得更高的信号。另外，通过确保来自样品中各个深度的信号之间的相互抑制，设计了有效的抑制脉冲。通过实验证明了该新方法的性能，用于激发问题的大块锂样品，以及用于选择性抑制脉冲的双相金属/液体样品。