What is magnetic **** vibration in medicine?

Magnetic **** vibration magneticresonance (MRI); solid in a constant magnetic field and high-frequency alternating electromagnetic field **** the same action, in the vicinity of a certain frequency produces a **** vibration absorption phenomenon of high-frequency electromagnetic field. The magnetization of a solid under the action of a constant external magnetic field occurs, and all the metamagnetic moments in the solid have to be advanced around the external magnetic field. Due to the presence of damping, this in-motion is quickly attenuated. But if a high-frequency electromagnetic field perpendicular to the direction of the external magnetic field, when its frequency and the frequency of the same into the action, it will be absorbed from the alternating electromagnetic field in order to maintain its into the action of the solid on the incident high-frequency electromagnetic field energy in the frequency of the above to produce a * * * vibration absorption peak. If the magnetic *** vibration of the magnetic moment is a paramagnetic body in the atomic (or ion) magnetic moment, it is called paramagnetic *** vibration; if the magnetic moment is the atomic nucleus of the spin magnetic moment, it is called nuclear magnetic *** vibration. If the magnetic moment is the spin magnetic moment of an electron in a ferromagnet, it is called a ferromagnetic **** vibration. The nuclear magnetic moment is about three orders of magnitude smaller than the electronic magnetic moment, so the frequency and sensitivity of the nuclear magnetic **** vibration is much lower than the paramagnetic **** vibration; similarly, the magnetic **** vibration of weak magnetic material sensitivity is lower than the strong magnetic material. From a quantum mechanical point of view, the magnetic moment of the electron and the nucleus under the action of the external magnetic field is spatially quantized, and accordingly has a discrete energy level. When the applied high-frequency electromagnetic field energy hv is equal to the spacing of the energy levels, electrons or atomic nuclei from the high-frequency electromagnetic field absorbs energy, so that it from the low energy level jump to the high energy level, thus forming an absorption peak at the *** vibration frequency. The use of paramagnetic *** vibration can be used to study the molecular structure and the electronic structure of defects in crystals and so on. Nuclear magnetic **** vibration spectrum is not only related to the chemical elements of the substance, but also affected by the chemical environment around the atom, so nuclear magnetic **** vibration has become an important means to study the structure of solids, chemical bonding and phase transition processes. Nuclear magnetic **** vibration imaging technology with ultrasound and X-ray imaging technology has been commonly used in medical examinations. Ferromagnetic *** vibration is an important method to study dynamic processes in ferromagnets and to measure magnetic coefficients.