Diffraction effects on bulk-wave ultrasonic velocity and attenuation measurements
Diffraction effects on bulk-wave ultrasonic velocity and attenuation measurements
复制标题
衍射效应对体波超声速度和衰减测量的影响
DOI：
10.1121/1.429587
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. Arakawa
中科院分区：
文献类型：
--
作者：
J. Kushibiki;M. Arakawa
通过测量VHF范围内射频（rf）音暴信号的幅值和相位，在一端有超声波换能器的缓冲棒、水耦合剂和合成硅玻璃固体试样组成的超声波传输线中，实验观察到由于衍射引起的损耗和相位提前。测量结果与衍射精确积分表达式的计算结果吻合较好。为了实现更精确的测量，研究了衍射对该频率范围内测量的速度和衰减的影响及其校正。结果表明，衰减测量值受衍射损失的影响，可以通过数值计算进行修正；速度测量值受衍射引起的相位超前的影响。研究表明，在复模速度测量中，速度由信号的测量相位确定，通过衍射数值计算的修正，可以得到各频率处的真实速度。在此基础上，提出了一种新的幅模速度测量校正方法。该方法通过对双脉冲法产生的叠加信号进行超声频率扫频得到的干涉输出间隔来确定速度。速度可以在菲涅耳区域的频率上精确测量，而衍射校正对于获得具有五个或更多有效数字的高精度值是必不可少的。
The loss and phase advance due to diffraction are experimentally observed by measuring the amplitude and phase of radio frequency (rf) tone burst signals in the VHF range, in an ultrasonic transmission line consisting of a buffer rod with an ultrasonic transducer on one end, a couplant of water, and a solid specimen of synthetic silica glass. The measured results agree well with the calculated results from the exact integral expression of diffraction. The diffraction effects on the velocity and attenuation measured in this frequency range and their corrections are investigated to realize more accurate measurements. It is shown that attenuation measurements are influenced by diffraction losses and can be corrected by numerical calculations, and that velocity measurements are affected by the phase advance caused by diffraction. This investigation demonstrates that, in complex-mode velocity measurements, in which the velocity is determined from the measured phase of the signals, the true velocity at each frequency can be obtained by correction using the numerical calculation of diffraction. Based on this result, a new correction method in amplitude-mode velocity measurements is also proposed. In this new method, the velocity is determined from the intervals of interference output obtained by sweeping the ultrasonic frequency for the superposed signals generated by the double-pulse method. Velocity may be measured accurately at frequencies in the Fresnel region, and diffraction correction is essential to obtain highly accurate values with five significant figures or more.
VHF/UHF范围生物超声波光谱系统和方法
DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
N. Akashi;M. Arakawa;H. Odagawa;T. Sannomiya;J. Kushibiki;N. Chubachi,and F. Dunn
通讯作者：
N. Chubachi,and F. Dunn