Applications in Traditional Industries
We have already mentioned the practical applications of some magnetic materials when we talked about their magnetic origin, electromagnetic induction, and magnetic devices. In fact, magnetic materials have been widely used in various aspects of conventional industry.
For example, without magnetic materials, electrification would be impossible, because generators are used for power generation, transformers for power transmission, electric motors for electrical machinery, and loudspeakers for telephones, radios, and televisions. Numerous instruments and meters are used in the magnet coil structure. These have already been covered in the rest of the story.
Magnets in medicine
Pigeon fanciers know that if pigeons are released hundreds of kilometers away, they will still return to their nests automatically. Why do pigeons have such good home-recognition skills? Originally, pigeons are very sensitive to the earth's magnetic field, they can use the earth's magnetic field changes to find their own home. If a magnet is tied to the pigeon's head, the pigeon will get lost. If pigeons fly over a radio transmission tower, the powerful electromagnetic interference will also disorient them. In medicine, the use of nuclear magnetic **** vibration can diagnose abnormal tissues in the human body and determine diseases, which is the more familiar nuclear magnetic **** vibration imaging technology, the basic principle is as follows: the atomic nucleus carries a positive electric charge and undergoes spin motion. Normally, the arrangement of the spin axis of the nucleus is irregular, but when it is placed in an applied magnetic field, the nuclear spin space orientation transitions from disorder to order. The magnetization vector of the spin system grows gradually from zero, and when the system reaches equilibrium, the magnetization strength reaches a stable value. If the nuclear spin system is subjected to external effects, such as a certain frequency of radio frequency excitation of the nucleus can cause *** vibration effect. In the radio frequency pulse stops, the spin system has been excited nuclei, can not maintain this state, will return to the magnetic field in the original arrangement of the state, at the same time to release a weak energy, become radio signal, the many signals detected, and make it when the spatial resolution, you get the distribution of nuclei in the movement of the image. Nuclear magnetic **** vibration is characterized by the flow of liquid does not produce a signal called the flow effect or flow blanking effect. Thus blood vessels are grayish-white tubular structures, while blood is black with no signal. This makes the blood vessels easily soft tissue separated. The normal spinal cord is surrounded by cerebrospinal fluid, which is black, and has white dura mater lined with fat so that the spinal cord shows up as a white, strongly signaling structure. MRI*** vibration has been applied to diagnostic imaging of systems throughout the body. The best results are the cranial brain, and its spinal cord, the heart large blood vessels, joints bones, soft tissues and pelvis. For cardiovascular disease can not only observe the anatomical changes of the chambers, great vessels and valves, but also ventricular analysis, qualitative and semi-quantitative diagnosis, can be made for a number of cross-sectional maps, high spatial resolution, showing the whole picture of the heart and lesions, and its relationship with the surrounding structures, is superior to other X-ray imaging, two-dimensional ultrasound, nuclide and CT examination. Magnetism is not only diagnostic, but can also help treat diseases. Magnet is an herb used in ancient Chinese medicine. People use the magnetic difference between different components of blood to separate red and white blood cells. In addition, the interaction of magnetic field and human meridians can realize magnetic therapy, which is unique in treating many kinds of diseases, and has been applied to magnetic therapy pillows, magnetic therapy belts and so on. Iron removers made of magnets can remove iron dust that may exist in flour, etc., magnetized water can prevent boiler scaling, and magnetized seeds can increase crop yields to a certain extent.
Magnetic applications in astronomy and other fields
We already know that the earth is a huge magnet, what is the connection between it and geological conditions? And what about magnetic fields in the universe?
At least in pictures we have all seen the brilliant Northern Lights. The Northern Lights have been recorded in China 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 geomagnetic field, as if a wire with an electric current is stressed in a magnetic field, causing these particles to move toward the north and south poles and converge, and collide with thin gases high in the Earth's atmosphere, which results in the excitation of the gas molecules, which in turn emit light.
Sunspots are regions on the Sun where magnetic activity is very intense. Sunspot eruptions can have an impact on our lives, such as temporarily disrupting radio communications. Therefore, the study of sunspots is of great importance to us.
Changes in geomagnetism can be used to explore for mineral deposits. Since all materials have strong or weak magnetic properties, if they come together to form an ore deposit, they will inevitably interfere with the geomagnetic field of the nearby area, causing anomalies in the field. According to this, the magnetic properties of the earth can be measured on land, at sea, or in the air, and a geomagnetic map can be obtained. Analysis and further exploration of the areas of magnetic field anomalies on the geomagnetic map can often lead to the discovery of unknown mineral deposits or special geological formations.
Rocks of different geological ages often have different magnetic properties. Therefore, the magnetic properties of rocks can be used to assist in determining changes in geologic age and crustal shifts.
Many mineral resources are ****ogenic, meaning that several minerals are mixed together, and they have different magnetic properties. The use of this feature, people developed a magnetic separator, the use of different components of the different magnetic properties of minerals as well as the difference between the strength of the magnetic properties, with a magnet to attract these substances, then they are subject to the attraction of the difference, the result can be mixed together with the different magnetic properties of the minerals to separate, the realization of the magnetic separation of minerals.
Magnetic applications in the military field
Magnetic materials are also widely used in the military field. For example, ordinary mines or mines can only explode on contact with the target, and therefore have a limited effect. However, if a magnetic sensor is installed on a mine or a landmine, because tanks or warships are made of steel, when they are close to (without touching the target), the sensor can detect changes in the magnetic field to make the mine or landmine explode, thus increasing the lethality.
In modern warfare, air control is one of the keys to winning a battle. However, the airplane is easily detected by the enemy's radar in the process of flight, thus having a greater danger. In order to avoid enemy radar monitoring, can be coated with a special layer of magnetic material on the surface of the aircraft - wave-absorbing material, which can absorb the electromagnetic waves emitted by the radar, so that the radar electromagnetic waves touching the aircraft, only a small number of electromagnetic waves reflect, so the enemy radar can not detect the radar echo, can not be found on the aircraft, which makes the aircraft to achieve the purpose of stealth. This is the famous "stealth aircraft". Stealth technology is a major hotspot in the world of military research. The U.S. F117 stealth fighter is an example of the successful use of stealth technology.
In the U.S. "Star Wars" program, there is a new type of weapon "electromagnetic weapons" development research. Conventional artillery utilizes the thrust generated by the instantaneous expansion of the munition when it explodes to rapidly accelerate the projectile and push it out of the cannon. On the other hand, an electromagnetic cannon puts the shell in a solenoid, energizes the solenoid, and the magnetic field generated by the solenoid generates a huge push force on the shell, which shoots the shell out. This is called an electromagnetic cannon. Similarly, there are electromagnetic missiles and so on.