Yinyan Ultrasonic Bian Xiao answers for you: The ultrasonic wave you use in underwear factory is also an ultrasonic underwear sewing machine, which will not cause harm to human body. When ultrasound propagates in the organism, it will change the function and structure of the organism through the interaction between tissues, which is the biological effect of ultrasound. The mechanism of biological effect is thermal effect and cavitation effect. The so-called thermal effect means that a part of energy is absorbed by biological tissues and converted into heat energy, which raises the temperature of the tissues; Cavitation effect refers to the interaction between ultrasound and gas nuclei or microbubbles in the tissue during propagation, which makes them burst suddenly, producing huge instantaneous pressure and changing the internal structure of the tissue. Low-dose ultrasound is a potential carcinogenic and teratogenic factor, and different frequencies and sound intensities are harmful to different individuals. Because ultrasonic wave has a strong penetration ability to both solid and liquid, when the energy is large, it can make the material particles vibrate at high frequency, and part of the energy can also be converted into heat energy, which will raise the local temperature. When high-intensity pulsed ultrasound propagates in liquid containing micron-sized bubbles, it can cause bubbles to contract, expand and even explode violently. This phenomenon is called "cavitation". Not long ago, Carstensen, a famous American super biophysicist, pointed out that the maximum output intensity of some ultrasonic image diagnostic instruments currently used in clinic has reached 1kw/cm2, which is enough to make organisms generate transient cavitation. For living things, cells near explosion bubbles will be damaged during transient cavitation. Generally speaking, in most human organs and biological fluids, a small number of cells will not be harmed.