Study On The Doublet Mechanics And Acoustic Radiation Force

With the development of science and technology, high-frequency ultrasound has be put into research and application, the paper focuses ultrasound research in two aspects:doublet mechanics and acoustic radiation force.With the increase frequency of sound wave used in biological tissue, the discrete nature of biological tissue becomes clear. Therefore, in the high-frequency field doublet mechanics becomes increasingly important. When the tissue is pathological, the internodal distance of the tissue and the sound velocities change at different frequencies. By increasing the frequency, the difference of the sound speed between pathological tissue and normal tissue is increased. And the sound attenuation will decrease with the increase of the internodal distance, And the sound velocity and attenuation imaging at high frequency can be used to obtain the change of the internodal distance,which can be determined the extent of the lesion and the micro-structure of the tissue, the theory provides a new method for the ultrasound tissue characterization.The second part is the acoustics radiation force on tiny particles in the sound field, acoustic radiation force can operate and capture particle by sound field effects. which has important applications in biomedicine and materials science. Taking Gaussian wave for double layer sphere as an example, this section presents the scattering theory of sound field, analyses the influence of different boundary conditions, and derives acoustics radiation force function for double layer sphere with Gaussian wave’s spherical function expansion by using the method of finite series expansion. Acoustic radiation force characteristics of double layer spherical particles are researched systemtically through theoretical derivation and numerical analysis, which will play an important role in non-destructive control on industry and medicine.