Application of NdFeB magnet in traditional industry

When talking about the source of magnetic materials, electromagnetic induction, and magnetic devices, we have already mentioned some magnetic materials

Practical application. In fact, magnetic materials have been widely used in all aspects of traditional industries.

For example, if there is no magnetic material, electrification becomes impossible, because power generation uses generators, power transmission uses transformers, and electrical machinery uses motors, telephones, radios, and televisions to use speakers. Many instruments and meters must use the magnetic steel coil structure. These have already been mentioned in other content.

The application of neodymium iron boron magnets in medicine

Homing pigeon enthusiasts know that if pigeons are released hundreds of kilometers away, they will automatically return home. Why do pigeons have such good family recognition skills? It turns 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 home. If you attach a magnet to the head of the pigeon, the pigeon will get lost. If the pigeons fly over the radio tower, strong electromagnetic interference will also make them disoriented.

In medicine, nuclear magnetic resonance can be used to diagnose abnormal human tissues and determine diseases. This is the familiar nuclear magnetic resonance imaging technology. The basic principle is as follows: the nucleus is positively charged and spins. Under normal circumstances, the arrangement of nuclear spin axes is irregular, but when placed in an external magnetic field, the spatial orientation of nuclear spins transitions from disorder to order. 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 is subjected to external effects at this time, such as a certain frequency of radio frequency excitation of the nucleus can cause a resonance effect. After the radio frequency pulse is stopped, the excited nuclei of the spin system cannot maintain this state, and will return to the original arrangement state in the magnetic field. At the same time, they will release weak energy and become radio signals. These many signals are detected and made When performing spatial resolution at this time, an image of the distribution of nuclei in motion is obtained. The characteristic of nuclear magnetic resonance is that the flowing liquid does not produce a signal, which is called the flow effect or the flow blank effect. Therefore, blood vessels are gray-white tubular structures, while blood is black with no signal. This makes the blood vessels easy to separate the soft tissues. Normal spinal cord.

Surrounded by cerebrospinal fluid, the cerebrospinal fluid is black, and the white dura mater is set off by fat, making the spinal cord appear as a strong white signal structure. MRI has been used in imaging diagnosis of various systems throughout the body. The best effect is the brain, its spinal cord, heart and great blood vessels, joint bones, soft tissues and pelvis. For cardiovascular diseases, it can not only observe the anatomical changes of various chambers, large blood vessels and valves, but also perform ventricular analysis for qualitative and semi-quantitative diagnosis. It can make multiple cross-sectional views with high spatial resolution and display the full picture of the heart and disease , And its relationship with surrounding structures are 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 blind medicinal material of ancient Chinese medicine. People use the magnetic difference of different components in the blood to separate red blood cells and white blood cells. In addition, the interaction between the magnetic field and the meridians of the human body can realize magnetic therapy, which has a unique role in the treatment of various diseases. There have been applications such as magnetic therapy pillows and magnetic therapy belts. The iron remover made of magnets can remove iron dust that may exist in flour, etc., magnetized water can prevent boiler fouling, and magnetized seeds can increase crop yields to a certain extent. [3]

Magnetic applications in astronomy and other fields

We already know that the earth is a huge magnet. How does it relate to geological conditions? What about the magnetic field in the universe?

At least in the pictures we have seen the brilliant northern lights. China has had records of the Northern Lights since ancient times. The Northern Lights are actually the result of the interaction between particles in the solar wind and the geomagnetic field. The solar wind is a stream of high-energy charged particles emitted by the sun. When they reach the earth, they interact with the earth’s magnetic field, just like a current carrying wire is subjected to a force in a magnetic field, causing these particles to move and gather to the north and south poles, and collide with the rare gas in the upper air of the earth, resulting in gas Molecules are excited to emit light.

Sunspots are areas on the sun where the magnetic field is very active. The outbreak of sunspots will have an impact on our lives, such as temporarily interrupting radio communications. Therefore, studying sunspots is of great significance to us.

Changes in geomagnetism can be used to explore mineral deposits. Since all substances have strong or weak magnetism, if they gather together to form a mineral deposit, they will inevitably interfere with the geomagnetic field in the nearby area, causing abnormalities in the geomagnetic field. Based on this, it is possible to measure the magnetism of the earth on land, ocean or air, obtain a geomagnetic map, analyze and further explore areas with abnormal magnetic fields on the geomagnetic map, and often discover unknown mineral deposits or special geological structures.

Rocks of different geological ages often have different magnetic properties. Therefore, we can use the magnetism of rocks to assist in judging changes in geological age and crustal changes.

Many mineral resources are symbiotic, which means that several minerals are mixed together, and they have different magnetic properties. Using this feature, people have developed a magnetic separator that uses the different magnetic properties of minerals of different components and the difference in magnetic strength. When magnets are used to attract these substances, the attraction they receive is different. As a result, they can be mixed together. Different magnetic minerals are separated to realize magnetic beneficiation.

NdFeB magnets in military applications

Magnetic materials have also been widely used in the military field. For example, ordinary sea mines or land mines can only explode when they touch the target, so their effect is limited. And if magnetic sensors are installed on mines or landmines, because tanks or warships are made of steel, when they are close (without touching the target), the sensors can detect changes in the magnetic field that cause the mines or landmines to explode, increasing the lethality.