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: http://acs366.phys.msu.su/isna16/Abstracts/ALifeofSonoluminescingBubbles.htm
Дата изменения: Wed Jul 10 21:26:58 2002 Дата индексирования: Mon Oct 1 21:17:13 2012 Кодировка: |
Abstract |
A Life of Sonoluminescing Bubbles
K.Yasui (National Institute of Advanced
Industrial Science and Technology, Moriyama-ku Nagoya, Japan)
e-mail:
k.yasui@aist.go.jp
Computer
simulations of bubble oscillations are performed under conditions of
multibubble sonoluminescence(MBSL) in water in order to study a life of
bubbles. Bubbles are classified into
five categories by their ambient radii.
They are dissolving bubbles, stable sonoluminescing bubbles, unstable
sonoluminescing bubbles, unstable bubbles, and "degas" bubbles. The
range of the ambient radius for each category depends on the frequency and
amplitude of ultrasound. A bubble emits light immediately after its appearance
when the ambient radius is in a certain range, while the previous theory
predicts that a bubble emits light only when it grows to the resonance size by
rectified diffusion. The main mechanism
of the bubble growth to a "degas" bubble is not the rectified
diffusion but coalescence. The mechanism of the light emission depends on the
frequency of ultrasound. As the frequency of ultrasound increases, the amount
of water vapor trapped inside bubbles at the collapse decreases. As a result,
MBSL originates mainly in plasma emissions at 1 MHz while it originates in
chemiluminescence of OH radicals and plasma emissions at 20 kHz.
Section
: 4