吸收媒质中非线性Gauss聚焦超声场的仿真研究  

Simulation study of a nonlinear focused Gaussian ultrasonic field in absorbing medium

作　　者：杜宏伟[1] 彭虎[1] 韩雪梅[1] 杨晓宇[1] 冯焕清[1] 

机构地区：[1]中国科学技术大学电子科学与技术系,安徽合肥230027

出　　处：《中国科学技术大学学报》2007年第9期1120-1124,共5页JUSTC

基　　金：国家自然科学基金(60471057);中国科学技术大学青年科学基金(KA2100230001)资助

摘　　要：通过频域有限差分法求解KZK方程,对吸收媒质中Gauss聚焦超声换能器的基波和高次谐波声场进行计算和仿真,研究了各次谐波沿传播方向的分布规律,发现高次谐波声场同样具有Gauss聚焦特性,并且谐波阶次越高,聚焦特性越好.此后讨论了不同的吸收系数对Gauss声场聚焦特性的影响,结果显示吸收系数的改变不会影响Gauss声场的径向分布形状,但吸收系数的增加导致聚焦区域声场强度的减弱,甚至聚焦无法实现.The fundamental and higher-order harmonic acoustic fields of a focused Gaussian ultrasonic transducer in absorbing medium were computed and simulated by solving the KZK equation using a frequency domain finite difference method. The distribution of every harmonic component along the propagation direction was investigated. The result indicates that these harmonic fields are also focused Gaussian beams and that the focused property of the harmonic field improves with the increase of harmonic order. Variant absorption coefficient＇s influence on the focused property of the field was analyzed, and result shows that the variation of absorption coefficient does not influence the radial shape of the beam, but impossibility,the increase of the absorption coefficient results in the attenuation of field intensity, rendering focusing an impossibility.

关 键 词：Gauss聚焦波 KZK方程 有限差分法 

分 类 号：R318.04[医药卫生—生物医学工程]