引言双共振是核磁共振(NMR)谱中的一种特种技术。运用双共振时,磁场B_2和扫描磁场B_1同时作用于样品,从而使部分共振得到饱和。这种实验结果的变化范围很广,它取决于B_2的频率和强度。双共振的重要现象之一是核Overhauser效应(NOE)。NOE的定义是当某一自旋的NMR吸收得到饱和时,另一自旋的NMR吸收强度积分值的改变。自从Solomon和Bloemberson首次描述NOE以来,有关NOE的理论和实际应用的文献已经大量出版。目前,NOE已成为许多实验室的常规手段。 Introduction Double resonance is a special technique in nuclear magnetic resonance (NMR) spectroscopy. When using double resonance, the magnetic field B_2 and the scanning magnetic field B_1 act on the sample at the same time, so that part of the resonance is saturated. The results of this experiment vary widely, depending on the frequency and intensity of B_2. One of the important phenomena of double resonance is the Nuclear Overhauser Effect (NOE). The NOE is defined as the change in the integrated value of the NMR absorption intensity of another spin when the NMR absorption of a certain spin is saturated. Since the first description of NOE by Solomon and Bloemberson, the literature on the theory and practical application of NOEs has been published in large numbers. Currently, NOE has become a routine tool in many laboratories.