粘弹包膜气泡的声散射特性

Sound scattering characteristics of bubbles with viscoelastic shells

在线性条件下研究了单个粘弹包膜气泡的声散射特性,并用WT散射法求解了造影剂的多气泡散射特性。首先建立了超声造影剂中单个粘弹包膜气泡的声散射物理模型,结合包膜内外声波方程和边界条件解得散射矩阵,并得到散射系数。通过数值计算用简化散射截面积曲线来表征单个气泡的声散射特性,用声色散曲线和衰减系数曲线来表征气泡的集总散射特性。研究结果表明:增加包膜的弹性参数μe的值,不仅使得气泡共振频率增高,还使气泡散射共振峰值相应加大;增加包膜的粘性参数μv的值,将使得散射的共振峰值降低;气泡的另两个参数λe和λv对散射特性几乎没有影响。

Sound scattering characteristics of a single bubble with viscoelastic shell are studied using the linear theory. And the multiple scattering characteristics of ultrasound contrast agents are calculated by the WT method. Firstly, a physical model of sound scattering of this bubble is set up. Combining wave equations in and out of shell and boundary conditions, we deduced the scattering matrix and then the scattering coefficients. In addition, in numerical calculations, we take reduced scattering cross sections as measurements for sound scattering characteristics of the single bubble; and then the sound dispersion curves and the attenuation coefficient curves for multiple scattering of bubbles in water. The numerical results show that as the value of elastic parameter of the layer μe increases, both the resonant frequency and the resonant scattering amplitude increase; The resonant scattering amplitude decreases as the value of the viscous parameter of the layer μv increases; And usually, another two parameters of the layer, λe and λv, do not affect the sound scattering characteristics of the bubble.