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一、前言自旋量子数为1/2或更大的原子核具有磁矩。貭子和氟原子核正是这样的磁核,它們的自旋为1/2。把一个貭子放在磁場H_0中,則它占有两个能級之一,相当于核磁矩μ順着或反着磁場方向。这两种取向的能量差为△E=2μH_0 (1)能量△E必須予以吸收来使核自低能級跃迁至高能級,或在反向过程中放出。公式(1)示出,能量差和磁場强度成正比。在10,000高斯磁場中貭子的共振频率为42.6兆周/秒。把质子放在此频率的射頻場中(在样品管上绕线圈并以振荡器激发),同时在和线圈
I. INTRODUCTION Nuclei with a spin quantum number of 1/2 or more have a magnetic moment. The prickly heat and fluorine nuclei are just such magnetic cores that have a spin of 1/2. Putting a prong in the magnetic field H_0, it occupies one of two energy levels, which corresponds to the magnetic moment μ going down or in the opposite direction of the magnetic field. The difference in energy between these two orientations is ΔE = 2μH_0 (1) The energy ΔE must be absorbed to cause the nucleus to transition from a low energy level to a high energy level or to emit it in the opposite direction. Equation (1) shows that the energy difference is proportional to the magnetic field strength. The resonance frequency of the clapper in the 10,000 gauss magnetic field is 42.6 trillion cycles per second. Place the protons in this frequency RF field (coil around the sample tube and excite with the oscillator)