Application in traditional industries:
When discussing the magnetic sources, electromagnetic induction, and magnetic devices of magnetic materials, we have already mentioned the practical applications of some magnetic materials. In fact, magnetic materials have been widely used in various aspects of traditional industry.
For example, without magnetic materials, electrification becomes impossible, as electricity generation requires generators, transmission requires transformers, power machinery requires electric motors, telephones, radios, and televisions require speakers. Many instruments and meters require the use of magnetic steel coil structures. These have already been mentioned in the other content.
Magnetic applications in the biological and medical fields:
Pigeon enthusiasts all know that if pigeons are released hundreds of kilometers away, they will automatically return to their nest. Why do pigeons have such good family recognition skills? Originally, pigeons are very sensitive to the Earth's magnetic field, and they can use the changes in the Earth's magnetic field to find their own homes. If a magnet is tied to the head of a pigeon, it will get lost. If pigeons fly over radio towers, powerful electromagnetic interference can also cause them to lose their direction.
In medicine, nuclear magnetic resonance imaging (MRI) can be used to diagnose abnormal tissues in the human body and determine diseases. This is a familiar MRI technology, and its basic principle is as follows: atomic nuclei are positively charged and undergo spin motion. Normally, the arrangement of atomic spin axes is irregular, but when placed in an external magnetic field, the spatial orientation of nuclear spin transitions from disordered to ordered. The magnetization vector of the spin system gradually increases from zero, and when the system reaches equilibrium, the magnetization intensity reaches a stable value. If the nuclear spin system is subjected to external forces, such as a certain frequency of radio frequency excitation of the atomic nucleus, resonance effects can be caused. After the radio frequency pulse stops, the excited atomic nuclei in the spin system cannot maintain this state and will return to their original arrangement in the magnetic field, releasing weak energy as radio signals. By detecting these signals and performing spatial resolution, the distribution image of the moving atomic nuclei can be obtained. The characteristic of nuclear magnetic resonance is that flowing liquids do not generate signals, which is called flow effect or flow blank effect. Therefore, blood vessels are gray white tubular structures, while blood is signalless black. This makes it easy for blood vessels to separate from soft tissues. The normal spinal cord is surrounded by cerebrospinal fluid, which is black and has a white dura mater highlighted by fat, making the spinal cord appear as a strong white signal structure. Magnetic resonance imaging has been applied to imaging diagnosis of various systems throughout the body. Effect * * * * * is the brain, its spinal cord, heart Great vessels, joint bones, soft tissue and pelvic cavity. For cardiovascular diseases, not only can we observe the anatomical changes of each chamber, Great vessels and valves, but also can make ventricular analysis, qualitative and semi quantitative diagnosis, and can make multiple sectional images with high spatial resolution, showing the whole picture of the heart and lesions, as well as their relationship with the surrounding structures, which is superior to other X-ray imaging, two-dimensional ultrasound, nuclide and CT examinations.
Magnetism can not only diagnose, but also help treat diseases. Magnet is a traditional Chinese medicine herb. Nowadays, people use the magnetic differences of different components in the blood to separate red blood cells and white blood cells. In addition, the interaction between magnetic field and human meridians can achieve magnetic therapy, which has unique effects in treating various diseases. There are already applications such as magnetic therapy pillows and belts. The iron remover made of magnets can remove iron particles that may exist in flour, etc. Magnetic water treatment can prevent boiler scaling, and magnetized seeds can increase crop production to a certain extent.
Magnetic applications in fields such as astronomy, geology, archaeology, and mining:
We already know that the Earth is a huge magnet, so where does its magnetism come from? Has it existed since ancient times? What is the connection between it and geological conditions? What is the magnetic field in the universe like?
At least we have seen the brilliant northern lights in the pictures. China has had records of the Northern Lights since ancient times. The aurora borealis is actually the result of the interaction between particles in the Solar wind and the Earth's magnetic field. The Solar wind is a stream of high-energy charged particles emitted by the sun. When they arrive at Terrestrial Time, they interact with the Earth's magnetic field, just like the wire with Charged current is forced in the magnetic field, which makes these particles move and gather towards the South and North Pole, and collide with the rarefied gas in the high altitude of the earth, resulting in the gas molecules being excited and emitting light.
Sunspot is the area where the magnetic field on the sun is very active. The eruption of Sunspot will have an impact on our life, such as temporarily interrupting radio communication. Therefore, the study of Sunspot is of great significance to us.
Changes in geomagnetism can be used to explore mineral deposits. Since all materials have strong or weak magnetism, if they are gathered together to form a deposit, they will inevitably interfere with the Earth's magnetic field in the nearby area, causing anomalies in the Earth's magnetic field. According to this point, we can measure the magnetism of the earth on land, at sea or in Aerial survey, obtain the geomagnetic map, analyze and further explore the areas with magnetic anomalies on the geomagnetic map, and often find unknown mineral deposits or special geological structures.
Rocks of different Geologic time scale often have different magnetic properties. Therefore, the changes of Geologic time scale and crustal changes can be judged according to the magnetism of rocks.
Many mineral resources are symbiotic, which means that several minerals are mixed together and have different magnetic properties. By utilizing this feature, people have developed magnetic separators that utilize the different magnetic properties and differences in magnetic strength of different mineral components to attract these substances. As a result, the magnetic attraction they receive is different, and the mixed minerals with different magnetic properties can be separated, achieving magnetic beneficiation.