Do you have any knowledge of ultrasound related technology?

Basic Introduction:

Ultrasound is a sound wave with a frequency higher than 20000 Hz, which is further divided into power ultrasound and detection ultrasound in practical applications. It has good directionality, strong penetration ability, and is easy to obtain concentrated sound energy. It can propagate over long distances in high-density solids and liquids, and can be used for ranging, industrial testing, medical ultrasound, cleaning, welding, drilling, gravel, sterilization and disinfection, etc.

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 can be heard by our human ears is between 20Hz and 20000Hz. When the vibration frequency of sound waves is less than 20Hz or greater than 20000Hz, we cannot hear them. Therefore, we refer to sound waves with frequencies above 20000 hertz as' ultrasonic waves'. The ultrasonic frequency commonly used for medical diagnosis ranges from 1 MHz to 10 MHz.

Theoretical research shows that under the same amplitude conditions, the energy of an object's vibration is directly proportional to the vibration frequency. When ultrasonic waves propagate 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 ultrasonic waves are introduced into a water tank, the intense vibration will cause the water in the tank to break into many small droplets. Then, a small fan can be used to 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 reach the affected area with medication. Using the principle of a humidifier to atomize the medication and allow the patient to inhale can improve the therapeutic effect. The enormous energy of ultrasound can also cause stones in the human body to undergo intense forced vibrations and shatter, thereby alleviating pain and achieving the goal of healing. Ultrasound is widely used in medicine, such as color ultrasound, B-ultrasound, and lithotripsy (such as gallstones, kidney stones, eye bags, etc.), which can also damage bacterial structures and disinfect items.

Generation method:

Sound waves are the form of propagation of mechanical vibration states (or energy) of objects. The so-called vibration refers to the round-trip motion of particles of a substance near their equilibrium position. For example, after the drum surface is struck, it vibrates up and down, and this vibration state propagates in all directions through the air medium, which is called sound wave. Ultrasound refers to a sound wave with a vibration frequency greater than 20000 Hz, and its frequency per second is very high, exceeding the general upper limit of human hearing (20000 Hz). People refer to this kind of invisible sound wave as ultrasound. Ultrasound and audible sound are essentially the same, and their common feature is a mechanical vibration mode that typically propagates in an elastic medium as a longitudinal wave, which is a form of energy propagation. The difference is that ultrasound has a high frequency, short wavelength, and good beam and directionality when  propagating along a straight line within a certain distance. Currently, the frequency range used for abdominal ultrasound imaging is between 2-5 MHz, Commonly used is 3~3.5 megahertz (1 vibration per second is 1Hz, 1 megahertz=10 ^ 6Hz, that is, 1 million vibrations per second, and the frequency of audible waves is between 16-20000 Hz).

The propagation laws of ultrasound in media, such as reflection, refraction, diffraction, and scattering, are not fundamentally different from those of audible sound waves. But the wavelength of ultrasound is very short, only a few centimeters, or even a few thousandths of a millimeter. Compared with audible sound waves, ultrasound has many strange characteristics: propagation characteristics - the wavelength of ultrasound is very short, and the size of typical obstacles is many times larger than that of ultrasound waves. Therefore, the diffraction ability of ultrasound is poor, and it can propagate in a straight direction in a uniform medium. The shorter the wavelength of ultrasound, the more significant this characteristic is.Leistungseigenschaften - Wenn sich Schall in der Luft ausbreitet, treibt er die Partikel in der Luft dazu, hin und her zu schwingen, wodurch Arbeit an den Partikeln verrichtet wird. Schallleistung ist eine physikalische Größe, die die Geschwindigkeit darstellt, mit der Schallwellen wirken. Je höher die Frequenz einer Schallwelle ist, desto größer ist bei gleicher Intensität ihre Leistung.

Aufgrund der hohen Frequenz von Ultraschall ist seine Leistung im Vergleich zu gewöhnlichen Schallwellen sehr hoch. Kavitation - Wenn sich Ultraschallwellen in einer Flüssigkeit ausbreiten, entstehen aufgrund der intensiven Vibration von Flüssigkeitspartikeln kleine Hohlräume in der Flüssigkeit. Diese kleinen Hohlräume dehnen sich schnell aus und schließen sich, was zu heftigen Kollisionen zwischen Flüssigkeitspartikeln führt, was zu Drücken von Tausenden bis Zehntausenden von Atmosphären führt. Die intensive Wechselwirkung zwischen Partikeln kann einen plötzlichen Temperaturanstieg der Flüssigkeit verursachen, wodurch ein guter Rühreffekt bereitgestellt wird, wodurch zwei nicht mischbare Flüssigkeiten (wie Wasser und Öl) emulgiert werden, die Auflösung von gelösten Stoffen beschleunigt und chemische Reaktionen beschleunigt werden.Die verschiedenen Effekte, die durch die Einwirkung von Ultraschall in Flüssigkeiten verursacht werden, werden als Kavitationseffekt von Ultraschall bezeichnet.

Frequenz über 2 × Eine Schallwelle von 10 kHz. Der Zweig der Akustik, der die Erzeugung, Ausbreitung, den Empfang und verschiedene Ultraschalleffekte und -anwendungen von Ultraschall untersucht, wird als Ultraschall bezeichnet. Zu den Geräten, die Ultraschallwellen erzeugen, gehören mechanische Ultraschallgeneratoren (wie Gaspfeifen, Sirenen und Flüssigkeitspfeifen), elektrische Ultraschallgeneratoren, die nach den Prinzipien der elektromagnetischen Induktion und Aktion hergestellt werden, und elektroakustische Wandler, die unter Verwendung der elektrostriktiven Wirkung von piezoelektrischen Kristallen hergestellt werden der magnetostriktive Effekt ferromagnetischer Materialien.