2016/4/12 Magnetization and precessing:分子（磁极） 在静磁场B0中会绕静磁场方向进动 Normal State na magnetic field 6 600 Amagnetic dipole Resonance with RF:外加磁场B1(和B0垂直) 变化频率(RF)如果和磁极进动频率相同，则 发生共振，磁极吸收RF能量，自身能量升高 以 包aerpa0nerwi5ekMeneYpneandnsietetas in Figure(b),is induced in the receiver coil. 10 2016/4/12 10 Magnetization and precessing：分子（磁极） 在静磁场B0中会绕静磁场方向进动 A magnetic dipole Normal State In a magnetic field Resonance with RF：外加磁场B1（和B0垂直） 变化频率（RF）如果和磁极进动频率相同，则 发生共振，磁极吸收RF能量，自身能量升高 (a) After a 90 degrees RF pulse, M lies in the x‐y plane and rotates about the z‐axis. The component of M in the x‐y plane decays over time. An alternating current, shown in Figure (b), is induced in the receiver coil