抄録
Microbubbles are used as imaging agents to scatter effectively ultrasonic wave. Insonified microbubbles show oscillation including expansion and compression. Considering the effect of the nonlinear oscillation on their reflective wave, it is important to study about dynamics of microbubbles. A shell microbubble especially shows complicated oscillation called "compression only behavior". Such dynamics is often analyzed by using a model based on the experimental report, in which the surface tension of the bubble membrane decreases with compression of the bubble, leading to a buckling. However, this is a phenomenological model, and then, its theoretical background is not clear enough yet. In this research, we studied two different approaches about membrane molecules in micro domain of boundary surface neighborhood. Firstly, the stability of an array of membrane molecules was calculated with the Lennard Jones potential for a simplified molecular model. Secondly, the array of membrane molecules on some calculation conditions for different molecular densities was investigated on molecular dynamics simulation. The results clearly show a possible buckling of a membrane molecule to the outer side or the inner side of the bubble surface.
