Ultrasonic waves in the military medical and industrial have greater use. It is applied according to the size of the power can be divided into power ultrasound and detection of ultrasound. Power ultrasound applications include welding, drilling, crushing, cleaning, emulsification, etc., they mostly belong to the ultrasound equipment that only emits and does not receive. The exact mechanism of ultrasonic processing is still not thoroughly understood. Detection of ultrasound in the military applications such as radar localization. Medical ultrasound can see through muscles and soft tissues, making this technology commonly used for scanning. Obstetric ultrasound is also commonly used during pregnancy. Doctors can use ultrasound imaging to visualize the body, but because ultrasound does not penetrate bone, it is not a complete replacement for X-rays, although it is less harmful. Typical ultrasound frequency of about 2MHz to 10MHz, the higher frequency is usually used in the urinary tract lithotripsy vibration. Detection of ultrasound equipment has both transmit and receive.
Ultrasonic waves can also be used for cleaning purposes, is currently the most effective way of cleaning, is generally believed to be the use of ultrasound in the liquid "cavitation". In Shamrock you can buy an ultrasonic cleaner for hundreds of dollars. Ultrasonic cleaning machine cleaning principle, in the use of ultrasonic vibration of water, so that the micro-fine bubbles generated in the water, so that the bubbles float to the surface of the water, the surface of the object to take away the grease or dirt. The frequency of the ultrasonic waves generated by the cleaner is about 20-40 kHz, which can be applied to the cleaning of jewelry, lenses or other optical instruments, dental appliances, surgical appliances and industrial parts.
In addition to the lower frequency can be issued purely mechanical ultrasonic whistle, the general ultrasonic equipment has ultrasonic power supply, transducer, amplitude lever, tool head and other components. Transducer piezoelectric ceramic transducer and magnetic transducer two kinds. The theory of the transducer and amplifier rod can also be considered a specialized discipline.
References:
http://zh.wikipedia.org/wiki/%E8%B6%85%E5%A3% B0%E6%B3%A2