本文仅限于对氢核(即质子)的讨论。质子犹如一细小条状磁体,将其置于外加磁场间,质子就可在场中排列,有的与场的方向相同,其余则与之相反;两个方向能级之差是一个量子。假使施用一个合适的频率,在低能级状态的质子,将吸收一个量子的能量跃迁到较高能级的状态。这种状况仅在频率刚适合时才出现,此即共振现象(Resonance phenomenon)。在质子邻近的轨道电子可产生其各自的小磁场,从而在磁场中产生一细小的变化,为质子 This article is limited to discussions of hydrogen nuclei (ie protons). Protons are like tiny strips of magnets that place them in an applied magnetic field. The protons can be aligned in the field, some in the same direction as the field, and the other in the opposite direction. The difference between the energy levels in both directions is a quantum. If a suitable frequency is applied, protons at a low energy level will transition one absorption quantum energy to a higher energy level. This condition occurs only when the frequency is right, which is the Resonance phenomenon. Electrons in the vicinity of protons can generate their own small magnetic field, resulting in a small change in the magnetic field for protons