Friday, January 28, 2011
The Mechanism and Advantages of Ultrasonic Wave
11:52 PM
hair styles
Ultrasonic waves are sound or vibration with a frequency too high to be heard by human ears, above approximately 20 kHz. Frequency is a measure of the number of repeated rounds per event in a given time interval. To calculate the frequency, someone set the interval, count the number of incident events, and dividing this count by long intervals. These results are