The nuclear magnetic resonance * * vibration is a physical process in which the spin energy level of the nucleus with non-zero magnetic moment splits Zeeman under the action of an external magnetic field, and the * * vibration absorbs a certain frequency of radio frequency radiation. Nuclear magnetic resonance spectrum is a branch of spectroscopy, its vibration frequency is in radio frequency band, and the corresponding transition is the transition of nuclear spin in nuclear Zeeman level.
Application of magnetic resonance imaging: Magnetic resonance imaging (MRI) has become a common image examination method. As a new imaging technique, magnetic resonance imaging will not affect human health.
However, there are six groups of people who are not suitable for MRI examination, that is, those who have pacemakers, those who have or are suspected of having metal foreign bodies in their eyeballs, those who have silver clip ligation of aneurysms, those who have metal foreign bodies or metal prostheses in their bodies, critically ill patients with life-threatening and claustrophobic patients. No monitoring instruments, rescue equipment, etc. Enter the MRI room. In addition, pregnant women less than 3 months pregnant, it is best not to do magnetic resonance imaging.
Extended data:
The nuclear magnetic vibration is mainly caused by the spin motion of the nucleus. Different nuclei have different spin motions, which can be expressed by the spin quantum number I of the nucleus. The spin quantum number is related to the atomic mass number and atomic number.
In the nuclear magnetic resonance spectrum, the area under the vibration peak of * * * is directly proportional to the number of protons producing the peak, so the peak area ratio is the relative ratio of different types of protons. If the number of protons in the whole molecule is known, the specific number of magnetic equivalent protons in each group can be calculated according to the proportional relationship of peak areas.
The peak area is measured by an electronic integrator, and the spectrum from low field to _ field is represented by a continuous step integral curve. The total number of integral curves is proportional to the total number of protons in the molecule, and the number of step curves of each peak is proportional to the peak area, that is, to the number of protons that produce absorption peaks.
The relative integral value of each peak area can also be directly displayed in figures on the spectrogram. If the peak area containing a proton is specified as 1, the number on the spectrum is consistent with the number of protons.