著者

宮本 昌季 田中 英司 一瀬 文子 松岡 辰郎 香田 忍

出版者

公益社団法人 化学工学会

雑誌

化学工学会 研究発表講演要旨集 化学工学会第70年会

巻号頁・発行日

pp.414, 2005 (Released:2005-08-30)

著者

田口 君彦 松岡 辰郎 香田 忍

出版者

日本ソノケミストリー学会

雑誌

ソノケミストリー討論会講演論文集

巻号頁・発行日

vol.15, pp.63-64, 2006

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The mechanism of ultrasonic degradation is still obscure, but it is well accepted that cavitation bubbles are mainly responsible for the degradation. The intense shear field generated by the collapse of the cavitation bubbles induces chain scission. Most of investigations on ultrasonic degradation have been carried out at low ultrasonic frequency around 20kHz. In this work, the ultrasonic degradation of methyl cellulose in aqueous solution was studied at two frequencies (20kHz and 500kHz) at the constant calorimetric power (20W) and temperature (25℃). The time variation of the average molecular weights and the molecular distribution were determined by Gel Permeation Chromatography (GPC). The mass average molecular weights (M_w) decreases with sonication time. The large lowering of M_w was observed at the frequency 500kHz. The degradation rate was suppressed by the addition of t-BuOH which act as a radical scavenger. The ultrasonic degradation rate coefficient k_d was estimated and compared with the results of other water-soluble polymers. The order of k_d value were PEO > Dextran 〓 Pullulan > MC. We will discuss on the frequency effects on the ultrasonic degradation.

著者

香田 忍

出版者

一般社団法人電子情報通信学会

雑誌

電子情報通信学会論文誌. A, 基礎・境界 (ISSN:09135707)

巻号頁・発行日

vol.89, no.9, pp.705-715, 2006-09-01

参考文献数

83

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超音波キャビテーションは5000K,千数百気圧の高温・高圧の局所場を与える.この反応場の化学的作用を利用したソノケミストリーの現状について概説する.超音波キャビテーションに由来する化学作用の機構について説明し,化学作用の定量化法を示す.更に,化学作用の周波数依存性を明らかにし,有機化学,無機化学,高分子化学,環境工学分野へのキャビテーションの化学作用の応用と問題点について述べる.

著者

福壽 快斗 朝倉 義幸 香田 忍

出版者

日本ソノケミストリー学会

雑誌

ソノケミストリー討論会講演要旨集

巻号頁・発行日

no.22, pp.39-40, 2013-10-25

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We have re-examined the frequency dependence of the cavitation threshold for air-saturated water and organic solvents. Cavitation threshold was estimated by observation of generation of cavitation from the results of the polymer degradation effect and acoustic spectrum. We used direct irradiation type and indirect irradiation type ultrasonic reactor in this experiment. All experiments were performed in the driving power 0.5〜50W, fluid volume 50mL, the driving frequency 20kHz〜5MHz. Cavitation threshold which is calculated from the results of the polymer degradation was larger than the cavitation threshold, which is calculated from the acoustic spectrum measurement. Regardless of solvents, in the frequency range below 45kHz, cavitation threshold decreased with increasing the frequency. Further, in the frequency range above 45kHz, cavitation threshold gradually increased with increasing the frequency.