Figure 1.

Acoustic attenuation of gel wax samples. Pulse-echo ultrasound signals acquired with two pairs of gel wax slabs (5 mm and 2 mm), with paraffin wax concentrations of 0% and 8%, are shown in (a) and (b), respectively. The measured acoustic attenuation of gel wax samples increased with paraffin wax concentration, and followed the frequency power law (${\alpha }_0{f}^n$) over a range of 3–10 MHz (c). For each paraffin wax concentration, the measured data represent average values from five repeated measurements; the error bars represent the standard deviations. The fit curve for each concentration is derived from the mean values for ${\alpha }_0$ and n that resulted from five repeated measurements. The values of ${\alpha }_0$ and n are listed in table 1.