کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1759534 | 1019282 | 2011 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Promoting inertial cavitation by nonlinear frequency mixing in a bifrequency focused ultrasound beam
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موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
آکوستیک و فرا صوت
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
Enhancing cavitation activity with minimal acoustic intensities could be interesting in a variety of therapeutic applications where mechanical effects of cavitation are needed with minimal heating of surrounding tissues. The present work focuses on the relative efficiency of a signal combining two neighbouring frequencies and a one-frequency signal for initiating ultrasound inertial cavitation. Experiments were carried out in a water tank, using a 550 kHz piezoelectric composite spherical transducer focused on targets with 46 μm roughness. The acoustic signal scattered, either by the target or by the cavitation bubbles, is filtered using a spectral and cepstral-like method to obtain an inertial cavitation activity measurement. The ultrasound excitations consist of 1.8 ms single bursts of single frequency f0 = 550 kHz excitation, in the monofrequency case, and of dual frequency f1 = 535 kHz and f2 = 565 kHz excitation, in the bifrequency case. It is shown that depending on the value of the monofrequency cavitation threshold intensity the bifrequency excitation can increase or reduce the cavitation threshold. The analysis of the thresholds indicates that the mechanisms involved are nonlinear. The progress of the cavitation activity beyond the cavitation threshold is also studied. The slope of the cavitation activity considered as a function of the acoustic intensity is always steeper in the case of the bifrequency excitation. This means that the delimitation of the region where cavitation occurs should be cleaner than with a classical monofrequency excitation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ultrasonics - Volume 51, Issue 1, January 2011, Pages 94-101
Journal: Ultrasonics - Volume 51, Issue 1, January 2011, Pages 94-101
نویسندگان
Izella Saletes, Bruno Gilles, Jean-Christophe Bera,