Docter, M.

bubble subharmonic frequency pressure resonance subharmonic response response microbubble diameter shell ultrasound j acoust soc surface tension amplitude van der meer resonance frequency subharmonic resonance frequency model contrast imaging 120 kpa oscillation surface behavior shell parameters tension phospholipid-coated microbubbles 50 kpa marmottant value carotid subharmonic resonance curves jong n agent result increase plaque figure subharmonic oscillations 100 kpa curve acoust gas bubbles decrease simulation nonlinear parameter study phospholipid-coated vasa vasorum subharmonic amplitude frequency range function versluis m range contrast agent microbubbles artery recording vasorum marmottant model shell elasticity radius frame subharmonic frequency threshold viscosity regime ultrasound contrast agents equation 4.40 system subharmonic resonance curve prosperetti elasticity cycle shell viscosity bubble dynamics resonance curves netherland stroke