Vibration can also destroy the world
Everything has two sides. Vibration does not always bring us good news. It also has huge consequences. hazards.
When it comes to the dangers of anti-incitement, the most well-known and cited example is the following example: In the middle of the 18th century, a group of soldiers marched majestically under the command of the commander. , walked in uniform steps across a bridge in Angers, France. When they were about to reach the middle of the bridge, the bridge suddenly shook violently and eventually broke and collapsed, causing many officers, soldiers and citizens to fall into the water and die. After investigation, it was found that the culprit of this tragedy was Zhen Zhen! Because when a large group of soldiers walked in unison, a frequency was generated that was exactly the same as the natural frequency of the bridge, which intensified the vibration of the bridge. When its amplitude reached the maximum and exceeded the bridge's pressure resistance, the bridge broke. Similar incidents also occurred in Russia and the United States. In view of this, the armies of many countries later had such a rule: when a large group of people crossed a bridge, they had to change from walking in unison to walking on foot.
For bridges, not only the heavy and neat footsteps of large groups of people can break them, but the seemingly invisible wind can also pose a threat to them. In 1940, the 860-meter-long Tacoma Bridge in the United States collapsed due to vibrations caused by strong winds. Although the wind speed at the time was less than 1/3 of the design wind speed limit, the actual strength of the bridge collapsed. The anti-vibration strength did not pass the test, which led to accidents. The tropical storms that wreak havoc along the coast every year also rely on the help of hurricanes to cause damage to houses and crops. In recent decades, there have been many incidents in countries and regions such as the United States and Europe where high-rise buildings swayed violently due to vibrations caused by strong winds.
It is also due to the power of oscillation that huge glaciers can be cracked by "gentle" ocean waves. Even the huge waves with a height of hundreds of meters that often appear in Liduya Bay in Alaska, USA, are due to the fact that the oscillation plays a great role in "fueling the flames". Because the Japanese are so powerful in "dominating" this bay, many sailors stay away from this bay with "respect".
Earthquakes that bring heavy casualties and property losses to humans also include "phantoms" of vibration: when a certain plate in the crust breaks, the frequency of the fluctuations is transmitted to On the ground, there was a strong vibration with the building, which caused the tragedy of house destruction and death.
In fact, the degree and scope of harm caused by vibration are far beyond this. Continuous sound of a certain frequency can cause the glass to break. The operation of the machine may damage the machine base due to vibration. A shout from a high mountain can cause the snow on the top of the mountain to tremble, causing a huge avalanche in an instant. If the rotation cycle of a moving car is synchronized with the inherent rhythm of the spring, the generated vibration can cause the car to lose control, causing a car crash and death...
People are living and producing. You will be exposed to various vibration sources, and these vibrations may cause harm to the human body. It is known from scientific tests that various parts of the human body have different natural frequencies. For example, the natural frequency of the eyeball is about 60 Hz at the maximum, and the natural frequency of the skull is about 200 Hz at the maximum. Looking at the human body as a whole, the natural frequency in the horizontal direction is about It is 3-6 Hz, and the natural frequency in the vertical direction is about 48 Hz. Therefore, operators who are very close to vibration sources, such as tractor drivers, operators of pneumatic picks, pneumatic shovels, electric saws, and nail boring machines, should try to avoid the frequency of these vibration sources being consistent with the natural frequencies of relevant parts of the human body when working. Produce *vibration. Moreover, in order to protect the safety and health of workers, relevant departments have made corresponding regulations, requiring that the frequency of various types of manually operated vibration machinery must be greater than 20 Hz.
What is particularly harmful to people is the vibration produced by infrasound waves. Infrasound is a sound wave that vibrates so few times per second that our ears cannot hear it. The sound frequency of infrasound waves is very low, generally below 20 MHz, but the wavelength is very long and is not easily weakened. Natural solar magnetic storms, roaring waves, thunder and lightning, sudden changes in air pressure, volcanic eruptions; military atomic bomb and hydrogen bomb explosion tests, rocket launches, aircraft flights, etc., can all produce infrasound waves. Around our work, study and life, there are many small power equipment that can generate infrasound waves, such as blowers, induced draft fans, compressors, vacuum pumps, diesel engines, electric fans, vehicle engines, etc. This magical function of infrasound waves has also attracted great attention from military experts. Some countries have used the properties of infrasound waves to develop infrasonic weapons. At present, they have developed infrasonic guns and infrasonic bombs. Both infrasonic guns and infrasonic bombs use infrasound waves with a frequency of 16-17 Hz to vibrate with certain organs in the human body, causing the organs of the vibrated person to deform, shift or bleed, thereby killing the enemy. purpose. Modern scientific research has proven that large amounts of infrasound waves emitted with a frequency of 16-17 Hz can cause unbearable tremors in the human body, resulting in symptoms such as visual impairment, disorientation, nausea, and even internal damage or rupture that can lead to death. . This kind of infrasonic weapon can be said to be the ultimate in technology for humans to use electromagnetic vibration to harm themselves.
How to eliminate the harm of earthquakes
Vibrations have brought unexpected disasters to people. So, can people eliminate these disasters? For this reason, through practice, people have summed up many methods to eliminate vibration.
According to historical records, some people in the Jin Dynasty of our country made a correct explanation of the phenomenon of vibration, and have been able to fully realize that the best way to prevent vibration is to change the inherent vibration of an object. frequency, so that the greater the difference between it and the frequency of external force, the better.
There is an interesting story in ancient times about how people cleverly eliminated vibration. During the Tang Dynasty, a musical instrument hanging in a monk's room in a temple in Luoyang often sounded automatically for no apparent reason. The monk became frightened and became ill, and sought treatment everywhere to no avail. He had a friend who was an official in charge of music in the imperial court, and he went to visit him after hearing the news. At this time, I heard the ringing of the bell in the temple, and the musical instrument sounded again. So my friend said: I can cure your disease because I have found the root cause of your disease. I just saw a friend find an iron file and grind it on the instrument a few times, and the instrument would no longer make any noise automatically. My friend explained that the vibration frequency of this instrument is consistent with that of the bells in the temple, so when the bell is struck, the instrument will ring accordingly. Now, if you file the instrument a little bit, it will change its natural vibration frequency. , it can no longer ring with the temple bell. The monk suddenly understood and the disease was cured.
Today, human beings have more diverse and advanced methods to deal with the harm of vibration. For example: in cinemas, broadcasting studios and other places that have high requirements for sound insulation, people often install some sponges, plastic foam or curtains so that the sound frequency cannot interact with these soft objects when they encounter them. ** vibrates, but is absorbed by them. Another example is that the motor should be installed on a cement-poured foundation, firmly connected to the earth, or installed on a heavy chassis, in order to increase the natural frequency of the foundation part to increase the vibration frequency (driving force) of the motor. frequency) to prevent foundation vibration.
Pedestrians on the street, the noise of vehicles, the rumble of machines - these continuous noises not only affect people's normal life, but also damage people's hearing. So people invented a muffler, which is composed of an orifice plate with many small holes and a cavity. When the frequency of the transmitted noise is the same as the natural frequency of the muffler, it will produce a violent explosion with the air column in the small holes. **Vibrate. In this way, a considerable part of the noise can be "swallowed" during vibration, and can also be converted into heat energy for use.
The use of vibration can bring welfare
In fact, the use of vibration by the Chinese can be traced back to a long time ago.
As early as the early Warring States Period, people at that time invented various types of buzzers to detect enemy situations. "Mozi·Bei Xue" records several of them:
Dig a deep pit at a certain distance under the base of the city wall, and bury a pottery urn with a capacity of seventy or eighty liters in the pit. The mouth of the urn is covered with leather, so that it actually becomes a buzzer. People with a keen hearing can lie on this buzzer and listen to the sound. Not only can they detect the sound of the enemy digging tunnels to attack the city, but they can also identify the direction and distance of the incoming enemy based on the difference in loudness of the sounds of each jar. Another method is to bury two leather-covered urns in the same pit, with the two urns separated by a certain distance, and use the difference in loudness between the two urns to determine the direction of the enemy.
The above methods have been used by military strategists of all ages. Qi Jiguang, a famous anti-Japanese general in the Ming Dynasty, used the above method to listen to the sound of the enemy digging tunnels. Even in some modern wars in this century, many countries and nations continue to use these methods.
In ancient times, our country also invented another type of buzzer that was lighter, simpler, and more practical. For example, in the army of the Tang Dynasty, there was a kind of military pillow called "Konghulu" made of leather, which soldiers with sensitive hearing and alert sleepers could use when camping. "A mortal horse can travel thirty miles away, east, west, north and south." Sound." When the sound propagates through the ground to the cavity, a reverberation is generated in the cavity, so the number and distance of the enemy can be known. It is worth mentioning that this method of listening to the ground with a bamboo tube is the origin of the modern medical stethoscope.
Song Dynasty scientist Shen Kuo cleverly used the principle of oscillation to design a little man dancing on the strings of the piano: first tune the strings of the piano or harp according to the normal playing needs, and then cut them. Some small paper figures are clamped on each string. When you play a certain string that does not clamp the paper figure, all the paper figures on the strings vibrating with it will jump and dance with the music. This invention preceded similar inventions in the West by centuries.
In modern times, with the development of science and technology and the deeper research into vibration, vibration has "oscillated" more frequently and closely in our society and life.
The sound box in a stringed instrument, the electrical resonance in a radio, etc. are to make the natural frequency of the system the same as the frequency of the driving force, causing vibration. We often see at construction sites that when construction workers are pouring concrete walls or floors, in order to improve the quality, they always pour concrete while vibrating it with an oscillator, so that the concrete becomes closer due to the oscillation effect. , more solid. In addition, crushers, vibration meters, electric vibration pumps, speed meters, etc. also use the vibration phenomenon to work.
After entering the 20th century, microwave technology has developed rapidly, bringing our human life into a new and more magical field. Microwave technology is a technology that uses vibration very delicately. Microwave technology is not only widely used in television, radio and communications, but also "enters the house" and is increasingly closely related to people's daily lives. Microwave ovens are the best embodiment of microwave technology in household applications. Electromagnetic waves with a frequency around 2500 Hz are called "microwaves". The vibration frequency of water molecules in food is roughly the same as that of microwaves. When a microwave oven heats food, a strong oscillating electromagnetic field is generated in the furnace, which forces the water molecules in the food to vibrate, causing oscillation and converting electromagnetic radiation energy into heat energy. , causing the temperature of the food to rise rapidly. Microwave heating technology is an overall heating technology for the interior of an object. It is completely different from the previous method of heating objects from the outside. It is an advanced technology that greatly improves heating efficiency and is extremely beneficial to environmental protection.
In one's life, one cannot do without the "bathing" and "moisturizing" of music, and beautiful and graceful music all contains stimulating "elves". Expert research believes that the frequency, rhythm and regular sound wave vibration of music are a kind of physical energy, and moderate physical energy can cause harmonious vibrations in human tissue cells. This vibration phenomenon caused by sound waves , will directly affect people's brain waves, heart rate, breathing rhythm, etc., causing the cell body to vibrate slightly, giving people a sense of comfort and ease, and the changes in rhythm make the person's body feel full and smooth. It activates the cells in the body, speeds up the flow of blood, and activates the life potential of people at the physical level. People have also found that when people are in a beautiful and pleasant music environment, it can improve the functions of the mental system, cardiovascular system, endocrine system and digestive system, prompt the human body to secrete an active substance that is beneficial to health, and increase the excitability of the cerebral cortex. Invigorating people's spirits, allowing people's souls to be cultivated and sublimated. Therefore, people have begun to use the excitement generated by music to relieve people's negative mental states such as tension, anxiety, and depression caused by various factors, and it can also be used to treat some psychological and physiological diseases of people.
We know that particle accelerators are crucial to the research and development of physics, and it is not an exaggeration to describe the use of particle accelerators in oscillation as "reaching the pinnacle". In the basic microuniverse of particle physics, each energy has a corresponding frequency, and vice versa. This is a natural principle of complementarity of matter, which has the characteristics of both waves and particles. Because matter has wave properties, it also has frequency. Particle accelerators use this principle of oscillation to superimpose many small "ripples" and turn them into large "wave crests", which can push electrons or protons to nearly the speed of light and collide at high speeds. Particles are produced below.
In short, *** vibration is not only an objective existence, it is also a scientific and technological field that needs to be further developed. Vibration technology is widely used in almost all scientific and technological fields such as machinery, chemistry, mechanics, electromagnetics, optics and molecules, atomic physics, and engineering technology. For example, the vibration of the speaker cone in audio equipment, the vibration of the sound chamber of various stringed instruments in the sound box, etc. use "mechanical vibration"; the reception and emission of electromagnetic waves use "electromagnetic vibration" ; The generation of laser utilizes "optical vibration"; in medical technology, there are already very popular "nuclear magnetic resonance" and so on. In the booming wave of information technology, genetic science, nanomaterials, and aerospace high science and technology that began in the 21st century, vibration technology has been widely used. Moreover, with the development of science, it is foreseeable that the *** vibration will have an even greater "shock" on our society.
Character introduction: Tesla (1856-1943), American, world-famous inventor, known as the King of Invention. He served as Edison's assistant and invented countless things that were beyond the times, paving the way for subsequent inventions, such as robots, radar, neon lights, fluorescent lights, radio remote control, wireless telegraph, steam turbines, high-frequency generators, speed meters, AC motors, etc. For example, the Tesla coil that is most commonly seen today was also his invention. His name has been adopted internationally as the unit of magnetic field. It is a pity that because his invention was too far ahead of his time, the economic benefits were not great, and he died penniless.