Shin-ichi Hatanaka

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Sonochemiluminescence (SCL) of luminol due to a single bubble is studied through spectral measurement. No SCL was observed from a stable single bubble that emitted high-intensity sonoluminescence (SL). In contrast, SCL was observed under conditions of an unstable dancing bubble, where a bubble grows and ejects tiny bubbles, making it "dance" by(More)
It is known that sonochemical reactions are enhanced by pulsing ultrasound. A method to optimize a sonochemical reactor using a pulsing operation was studied through the measurement of changes in sonoluminescence (SL) intensity from distilled water under various experimental conditions. It was confirmed that pulsing with a constant input power level(More)
Single-bubble sonoluminescence is generated in concentrated aqueous solutions of LiBr and LiCl. The moving-bubble state, a type of unstable state in which sonoluminescence is still emitted, is observed above the stable-sonoluminescence state similarly to that in aqueous solutions of NaCl and KCl. Luminosity is increased at similar magnitudes for LiBr, LiCl,(More)
Influence of clustering of cavitation bubbles on multibubble sonoluminescence (MBSL) in standing wave fields is studied through measurement of MBSL intensity with a photomultiplier tube and observation of corresponding bubble behavior with a high-speed video camera and an intensified charge-coupled device one. It is clarified that, when the SL is quenched(More)
The effects of dissolved gases on the sonochemical degradation of bisphenol A (BPA) were studied at a frequency of 500 kHz. BPA degradation rate increased in the order O(2)>Ar>air>N(2). The rate constant for oxygen (2.6 h(-1)) was approximately two fold higher than that for argon (1.2 h(-1)). A primary intermediate (2,3-dihydro-2-methylbenzofuran), a(More)
The efficiency of chemical reactions in the presence of ultrasound at reduced pressures has been monitored using the influence of dissolved oxygen (DO) content on a luminol solution undergoing multibubble sonoluminescence. From these measurements under the condition of constant ultrasonic frequency and constant amplitude of sound pressure, it is shown that(More)
Forced fluid flow can cause the enhancement of multibubble sonoluminescence (SL) under suitable conditions. The effect of directional flow with a circulator is similar to that of rotating flow with a stirrer. The mechanism of the enhancement is that both flows prevent cavitation bubbles from coalescing and clustering, which are responsible for the quenching(More)
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