Guinness pigeons fans all know that if the pigeons fly to hundreds of kilometers away, they will automatically homing. Why do pigeons have such a good ability to recognize it? It turned out that pigeons are very sensitive to the Earth's magnetic field, they can use the changes in the Earth's magnetic field to find their own home. If you put a magnet on the head of a pigeon, the pigeon will be trek. If the pigeons fly over the radio towers, the powerful electromagnetic interference can disorient them.

In medicine, the use of nuclear magnetic resonance can diagnose abnormal tissue in the body, to determine the disease, which is more familiar with our magnetic resonance imaging technology, the basic principle is as follows: the nucleus with a positive charge, and the spin movement. Under normal circumstances, the atomic spin axis arrangement is irregular, but when placed in an applied magnetic field, the nuclear spin space orientation from disorder to orderly transition. The magnetization vector of the spin system gradually increases from zero, and when the system reaches equilibrium, the magnetization reaches a stable value. If the nuclear spin system at this time by the outside world, such as a certain frequency of radio frequency excitation of the nucleus can cause resonance effect. After the radio frequency pulse is stopped, the nuclei of the spinning system that have been sharpened can not maintain this state, and will return to the original arrangement in the magnetic field, releasing the weak energy and becoming radio signals, detecting these many signals and making At the time of spatial resolution, you get the distribution of atomic nucleus in motion. Nuclear magnetic resonance is characterized by the flow of liquid does not produce a signal called the flow effect or flow blank effect. Therefore, blood vessels are gray tubular structure, and the blood is black without signal. This allows the blood vessels to be easily separated soft tissue.

Surrounding the normal spinal cord surrounded by cerebrospinal fluid, cerebrospinal fluid is black, and white hard film set off by the fat, so that the spinal cord showed a strong white signal structure. Nuclear magnetic resonance has been applied to the whole body system imaging diagnosis. The best is the brain, and its spinal cord, heart blood vessels, joint bones, soft tissue and pelvic and so on. Cardiovascular disease can not only observe the anatomy of the chambers, blood vessels and valves anatomical changes, and can be used for ventricular analysis, qualitative and semi-quantitative diagnosis, can be used for a number of sections, high spatial resolution, showing the whole picture of the heart and lesions , And its relationship with the surrounding structure, superior to other X-ray imaging, two-dimensional ultrasound, radionuclide and CT examination. Magnetism can not only diagnose but also help cure the disease. Magnetism is a blind Chinese herbal medicine. People use red blood cells and white blood cells to separate magnetic differences in different components of the blood. In addition, the magnetic field and human meridian interaction can achieve magnetic therapy, has a unique role in the treatment of a variety of diseases, there have been magnetic pillow, magnetic belt and other applications. Magnets made of iron separator can remove flour and other possible iron powder, magnetized water can prevent boiler fouling, magnetized seeds to some extent, the crop can be increased.