Le Lawrence H, Zhang Chan, Ta Dean, Lou Edmond
Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada T6G 2B7.
Ultrasonics. 2010 Jan;50(1):1-5. doi: 10.1016/j.ultras.2009.07.011. Epub 2009 Aug 7.
The slow compressional wave in air-saturated aluminum foams was studied by means of ultrasonic transverse transmission method over a frequency range from 0.2 MHz to 0.8 MHz. The samples investigated have three different cell sizes or pores per inch (5, 10 and 20 ppi) and each size has three aluminum volume fractions (5%, 8% and 12% AVF). Phase velocities show minor dispersion at low frequencies but remain constant after 0.7 MHz. Pulse broadening and amplitude attenuation are obvious and increase with increasing ppi. Attenuation increases considerably with AVF for 20 ppi foams. Tortuosity ranges from 1.003 to 1.032 and increases with AVF and ppi. However, the increase of tortuosity with AVF is very small for 10 and 20 ppi samples.
采用超声横向传输法，在0.2兆赫至0.8兆赫的频率范围内研究了空气饱和泡沫铝中的慢压缩波。所研究的样品具有三种不同的泡孔尺寸或每英寸的孔隙数（5、10和20 ppi），且每种尺寸都有三种铝体积分数（5%、8%和12% AVF）。相速度在低频时表现出轻微的频散，但在0.7兆赫之后保持恒定。脉冲展宽和幅度衰减明显，并随着ppi的增加而增大。对于20 ppi的泡沫，衰减随AVF显著增加。曲折度范围为1.003至1.032，并随AVF和ppi增加。然而，对于10和20 ppi的样品，曲折度随AVF的增加非常小。
