The spin of the atomic nucleus.
Nuclear magnetic **** vibration is mainly caused by the spin motion of atomic nuclei. The spin motion varies from nucleus to nucleus and can be expressed in terms of the spin quantum number I of the nucleus. There is a relationship between the spin quantum number and the mass number and atomic number of an atom.
Atomic nuclei are positively charged particles; nuclei that cannot spin have no magnetic moment, and nuclei that can spin have a circulating electric current that generates a magnetic field and forms a magnetic moment (μ). When the spin nucleus (spin nuclear) in the magnetic induction strength of B0 in the external magnetic field, in addition to spin, but also around the B0 movement, this movement is very similar to the gyroscope's movement, known as the larmor into action (larmor process).
The angular velocity ω0 of the spin core is proportional to the magnetic field induction strength B0, and the constant of proportionality is the magnetogyric ratio γ, where ν0 is the frequency of the process.
Expanded:
The principle of nuclear magnetic **** vibration is mainly caused by the spin motion of atomic nuclei. The spin motion varies from nucleus to nucleus and they can be expressed in terms of the spin quantum number I of the nucleus.
Observed H proton motion in the human body of an imaging, to do the examination, the examinee will be in a large magnet, that is, within a large cylinder, through the radiofrequency excitation, the human body of the different organs of the H protons have different activity conditions.
The RF pulses that are generated are absorbed by the coil to produce an image, so the imaging of the magnetic **** vibration is actually the imaging of the H plasmons in the body. Patients with pacemaker implants, fevers, and plasters are prohibited from undergoing magnetic **** vibration.
Baidu Encyclopedia - Principles of Magnetic **** Vibration