What are the effects and hazards of ultrasound, and what are the main uses of ultrasound?

Professional advice --- harmless! The principle of the software is to imitate the sound of male mosquitoes to repel them"Blood-sucking female mosquitoes"(Male mosquitoes and non-pregnant female mosquitoes do not bite, and pregnant female mosquitoes will only suck blood in order to reproduce the next generation)!The pregnant female mosquito will avoid the male mosquito!

The mosquito repellent software in PPD is to play the role of male mosquitoes! To say whether it is harmful or not, we must first clarify the following points: 1

The hearing range of the human ear is 20-20kHz!Sounds greater than 20kHz are ultrasound! 2.

In the mosquito repellent mode, there are three frequencies: 12300 Hz (sound wave Hz (sound wave Hz (ultrasound). In fact, in the environment of daily life, waves of these frequencies must exist!

Whether or not it will have an effect on the human body is mainly determined by the sound intensity, the duration of the action on the human body! But with its frequency and volume, it's not right at all....

Long-term exposure to ultrasound can cause a slight fever in human tissues; When the frequency is higher, the heat becomes more and more severe, causing the water molecules in the human body to be burned and the surrounding tissues to be destroyed, which is dangerous for a long time. Therefore, high-power and high-intensity ultrasound waves continue to act on the human body, which is harmful; The intermittent action of low-power ultrasound on the human body is beneficial. It's like someone giving you a light thump on the back and you're comfortable, but you're in pain or even hurt when you hit you hard.

Ultrasound is very important for navigation, and it is always used in hospitals, which makes a great contribution to it, but it also contains two sides.

It is very harmful to life, and it makes people feel annoyed and affects their lives!!

Low-dose ultrasound is a potential carcinogenic and teratogenic factor, and different frequencies and different sound intensities are harmful to different individuals. Because ultrasonic waves have a strong ability to penetrate solids and liquids, when the energy is large, it can make the particles of matter vibrate at high frequency, and part of the energy can also be converted into heat energy, so that the local temperature rises. When high-intensity pulsed ultrasound waves propagate in a liquid containing small bubbles in the micron range, they can cause the bubbles to shrink, expand, and even violently**, a phenomenon known as cavitation.

Not long ago, the famous American ultrabiophysicist Carlson pointed out that the maximum output intensity of ultrasound imaging diagnostic instruments used in some clinics has reached 1 kilowatt square centimeter, which is enough to cause transient cavitation of organisms. For organisms, cells near the bubble will be damaged during transient cavitation, and in general, in most organs and biological fluids in the human body, damage to a small number of cells will not cause harm to the human body.

(1) Engineering applications: underwater positioning and communication, underground resource exploration, etc.

2) Biological applications: shearing macromolecules, bioengineering and seed treatment, etc.

3) Diagnostics applications: A, B, M, D, double power and color ultrasound, etc.

4) ** Applications: physiotherapy, cancer treatment, surgery, extracorporeal lithotripsy, dentistry, etc.

Ultrasonic is a sound wave with a frequency of 20,000 hertz, which has good directionality, strong penetrating ability, easy to obtain more concentrated sound energy, and has a long propagation distance in water, which can be used for ranging, speed measurement, cleaning, welding, gravel, sterilization and disinfection. There are many applications in medicine, military, industry, and agriculture. Ultrasound gets its name from the fact that its lower limit of frequency is approximately equal to the upper limit of a person's hearing.

Ultrasonic has a wide range of applications, such as ultrasonic welding, ultrasonic cleaning, ultrasonic beauty, ultrasonic medicine, ultrasonic flaw detection, ultrasonic ranging, etc.

To say that there is no harm is also a lie, as long as you don't listen to it for a long time, it is not harmful to people, and it is best to configure professional earplugs for a long time in an ultrasonic environment. Ultrasonic waves are free of radiation and corrosion, just purely physical vibrations.

Ultrasound and infrasound waves are not stuffy to the human ear, but your nerves will feel it, and they are harmful to the human body in the long term, and harmless in the short term. For example, when metal welding exceeds the jujube sonic flaw detection, the staff must wear protective clothing, and other personnel must be 40 meters away.