Što je ultrazvuk?

Ultrasonic is a sound wave with a frequency higher than 20,000 Hz. It has good directionality, strong penetrating ability, and is easy to obtain concentrated sound energy. , sterilization, etc. There are many applications in medicine, the military, industry, and agriculture. Ultrasound is named because its lower frequency limit is greater than the upper limit of human hearing. Scientists refer to the number of vibrations per second as the frequency of sound, and it is measured in hertz (Hz). The frequency of sound waves that our human ear can hear is 20Hz-20000Hz. We call sound waves with frequencies above 20,000 Hz "ultrasonic". Ultrasound frequencies typically used for medical diagnosis are 1 MHz-30 MHz. Theoretical research shows that under the condition of the same amplitude, the vibration energy of an object is proportional to the vibration frequency. When the ultrasonic wave propagates in the medium, the frequency of the medium particle vibration is very high, so the energy is very large. In the dry winter in northern China, When the ultrasonic wave is passed into the water tank, the violent vibration will break the water in the tank into many small mist droplets, and then use a small fan to blow the mist droplets into the room, which can increase the indoor air humidity, which is the principle of the ultrasonic humidifier. Such as pharyngitis, bronchitis, and other diseases, it is difficult to use the blood flow to make the medicine reach the diseased part. Using the principle of the humidifier, the medicine liquid is atomized and inhaled by the patient, which can improve the curative effect.