Shao-Yi H.

Due to the improvement of the signal processing and image technology, the clinical ultrasound system becomes important assistant equipment for doctors to detect the diseases. Hence, it is necessary to know the biological effects of ultrasound in human tissue. In ultrasonic waves, the discrepancy between classical elasticity and experiment becomes a particularly important problem, especially for large frequencies and small wavelength, i.e., in the case of wave propagation in human tissue and compact bone. Consequently, the influence of the microstructure is important and this fact leads to the generation of new types of waves unknown in classical elasticity. Generalized continuum theories such as couple stress theory and micropolar theory have degrees of freedom in addition to those of classical elasticity. Such theories are thought to be applicable to composites with granular or porous structure, effective chiral composites and human compact bones. In this work, we illustrate the reflected and transmitted fields of an incident plane wave propagating on the elastic-human compact bone interface. It is predicted that there is some contribution for the ultrasound propagation in biological effects of human tissue.