Behavior of Ultrasound in Materials
Ultrasound is broadly defined as any sound having a frequency above 20 kHz, which is approximately the highest frequency that can be detected by the human ear. However, the acoustic microscopes emit ultrasound ranging from 5 MHz to beyond 400 MHz so that micrometre size resolution can be achieved. The ultrasound that penetrates a sample may be scattered, absorbed or reflected by the internal features or the material itself. These actions are analogous to the behavior of light. Ultrasound that is reflected from an internal feature, or (in some applications) that has traveled through the entire thickness of the sample, is used to make acoustic images.
Read more about this topic: Acoustic Microscopy
Famous quotes containing the words behavior of, behavior and/or materials:
“The ease with which problems are understood and solved on paper, in books and magazine articles, is never matched by the reality of the mother’s experience. . . . Her child’s behavior often does not follow the storybook version. Her own feelings don’t match the way she has been told she ought to feel. . . . There is something wrong with either her child or her, she thinks. Either way, she accepts the blame and guilt.”
—Elaine Heffner (20th century)
“Two things in America are astonishing: the changeableness of most human behavior and the strange stability of certain principles. Men are constantly on the move, but the spirit of humanity seems almost unmoved.”
—Alexis de Tocqueville (1805–1859)
“Herein is the explanation of the analogies, which exist in all the arts. They are the re-appearance of one mind, working in many materials to many temporary ends. Raphael paints wisdom, Handel sings it, Phidias carves it, Shakspeare writes it, Wren builds it, Columbus sails it, Luther preaches it, Washington arms it, Watt mechanizes it. Painting was called “silent poetry,” and poetry “speaking painting.” The laws of each art are convertible into the laws of every other.”
—Ralph Waldo Emerson (1803–1882)