CAJ | 학술논문

从流体动力学的基本方程出发，采用逐级近似微扰法，建立了理想流体媒质一至三级近似的波动方程，并得到三次谐波声压的积累解与声波传播距离的平方成正比.在此基础上进而求得三阶非线性声参量C/A与三次谐波声压之间的关系，这为下一步用有限振幅法测量和研究流体媒质的三阶非线性声参量C/A提供了理论基础.而三阶非线性参量预期在医学超声参数成像技术中有重要的应用前景.
종류체동역학적기본방정출발，채용축급근사미우법，건립료이상류체매질일지삼급근사적파동방정，병득도삼차해파성압적적루해여성파전파거리적평방성정비.재차기출상진이구득삼계비선성성삼량C/A여삼차해파성압지간적관계，저위하일보용유한진폭법측량화연구류체매질적삼계비선성성삼량C/A제공료이론기출.이삼계비선성삼량예기재의학초성삼수성상기술중유중요적응용전경.
Based on the basic equation of fluid dynamics, the wave equationsin the first-order,second-order and third-order approximations are established by the perturbation method. The accumulation solution of third-order harmonics sound pressure has a term proportional to the square of the distance. The solution gives explanation to the relationship between nonlinear parameter C/A and the sound pressure of third-order harmonics, thus providing a theoretical foundation for the measurement and study of the nonlinear parameter C/A of fluids by the finite amplitude method. It is expected that the third-order nonlinear parameter will have a good future in medical ultrasonic imaging.