Scientists' research on ultrasound

date：[2012-06-05] pk_hits：

Scientists refer to the number of vibrations per second as the frequency of sound, which is measured in hertz (Hz). The frequency of sound waves that our human ears can hear is between 20Hz and 20000Hz. When the vibration frequency of sound waves is less than 20Hz or greater than 20KHz, we cannot hear them. Therefore, we refer to sound waves with frequencies higher than 20000 hertz as ultrasonic waves. The ultrasound frequency commonly used for medical diagnosis is 1 MHz to 5 MHz.

Theoretical research has shown that under the same amplitude conditions, the energy of an object's vibration is directly proportional to the vibration frequency. When ultrasound propagates in a medium, the frequency of particle vibration in the medium is very high, resulting in a large amount of energy. In the dry winter of northern China, if ultrasound is introduced into a water tank, the intense vibration will break the water in the tank into many small droplets. Then, a small fan can blow the droplets into the room, which can increase indoor air humidity. This is the principle of ultrasonic humidifiers. For diseases such as pharyngitis and tracheitis, it is difficult to use blood flow to make drugs reach the affected area. By using the principle of humidifiers, the medication can be atomized and inhaled by patients, which can improve the therapeutic effect

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Scientists' research on ultrasound