中文摘要：

声速（SOS）是描述声波在媒质中传播特性的一个基本物理量，通过媒质中声速的测定，可以了解媒质的特性或状态变化．基于临界角侧波原理的超声速度测量方法是声速测量方法中的一种，但现有的临界角侧波测量方法精度较低，适用范围小，在测量声速时易受干扰．为此提出了一种新的基于临界角侧波理论的定量超声速度测量方法，该测量方法引入了一个新的参数—倾斜角补偿时间，该参数通过接收时间的差值求得．通过引入该参数，本方法在实际测量中提高了测量精度。

英文摘要：

Speed of sound （SOS） is a basic physical parameter which describes the propagation characteristics of acoustics in medium. By measuring SOS in medium, we can know the characteristics and the state of the medium. One of the SOS measurements is based on the principle of critical angle and lateral wave, but it has some disadvantages, such as low accuracy, small scope and surceptibility to interference. A new theory was thus proposed based on a new velocity measurement of quantitative ultrasound of lateral wave and critical angle. The method introduced a new parameter, the compensation time of inclination obtained from different values of receiving time. The proposed method is not subject interference from sorrounding tissues and improves measurement accuracy.