超声学.原位表征.有限振幅超声波束原位曝光估计

[中文适用范围]： 本技术规范规定： • 由于有限振幅声效应而导致的水中声学测量适用性限制的一般概念。 • 一种确保在准线性条件下进行测量的方法，以最大限度地减少有限幅度效应，该方法可应用于以下条件： − 频率范围为0.5 MHz 至15 MHz 的声场； − 由平面源和振幅增益高达 12 的聚焦源产生的声场； − 在垂直于声轴的平面内最大声压位于轴上的所有深度； − 圆形和矩形源几何形状； − 连续波和脉冲场； • 适合建立准线性条件的声学量的定义；作为准线性条件上限的声学量阈值； • 一种在水中非线性传播条件下估计衰减声学量的方法。 [外文原描述]： This Technical Specification describes means to allow "attenuated" acoustic quantities to be calculated under conditions where the associated acoustic measurements, made in water using standard procedures, may be accompanied by significant finite-amplitude effects. This Technical Specification establishes: - the general concept of the limits of applicability of acoustic measurements in water resulting from finite-amplitude acoustic effects; - a method to ensure that measurements are made under quasi-linear conditions in order to minimise finite-amplitude effects; - the definition of an acoustic quantity appropriate for establishing quasi-linear conditions; - a threshold value for the acoustic quantity as an upper limit for quasi-linear conditions; - a method for the estimation of attenuated acoustic quantities under conditions of nonlinear propagation in water.