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The Relationship of Cavitation to the Negative Acoustic Pressure Amplitude in Ultrasonic Therapy 被引量:1
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作者 范庭波 屠娟 +3 位作者 罗林姣 郭霞生 黄品同 章东 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第8期59-63,共5页
The relationship between the cavitation and acoustic peak negative pressure in the high-intensity focused ultrasound (HIFU) field is analyzed in water and tissue phantom. The peak negative pressure at the focus is d... The relationship between the cavitation and acoustic peak negative pressure in the high-intensity focused ultrasound (HIFU) field is analyzed in water and tissue phantom. The peak negative pressure at the focus is determined by a hybrid approach combining the measurement with the simulation. The spheroidal beam equation is utilized to describe the nonlinear acoustic propagation. The waveform at the focus is measured by a fiber optic probe hydrophone in water. The relationship between the source pressure amplitude and the excitation voltage is determined by fitting the measured ratio of the second harmonic to the fundamental component at the focus, based on the model simulation. Then the focal negative pressure is calculated for arbitrary voltage excita- tion in water and tissue phantom. A portable B-mode ultrasound scanner is applied to monitor HIFU-indueed cavitation in real time, and a passive cavitation detection (PCD) system is used to acquire the bubble scattering signals in the HIFU focal volume for the cavitation quantification. The results show that: (1) unstable cavitation starts to appear in degassed water when the peak negative pressure of HIFU signals reaches 13.5 MPa; and (2) the cavitation activity can be detected in tissue phantom by B-mode images and in the PCD system with HIFU peak negative pressures of 9.0 MPa and 7.8 MPa, respectively, which suggests that real-time B-mode images could be used to monitor the cavitation activity in two dimensions, while PCD systems are more sensitive to detect scattering and emission signals from cavitation bubbles. 展开更多
关键词 of on HIFU The Relationship of Cavitation to the Negative Acoustic pressure Amplitude in ultrasonic Therapy in MODE is for
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Temperature and pressure characteristics of ultrasonic transducer and the amplitude spectra correction of echoes
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作者 YU Houquan QU Wanli and HUANG Zailu(Dept. of Electronics and Information Eng. Huazhong University of Science and Technology Wuhan 430074)WEI Zongzhou LEI Furong and QIANG yuming (Jinghan Logging Institution Qianjiang City, Hubei Province 433123)Receive 《Chinese Journal of Acoustics》 1997年第2期144-151,共8页
In this paper,the transfer functions of ultrasonic transducers under different temperatures are imitated according to Mason equivalent circuit. The relevant experiments are carried out. The results show that the trans... In this paper,the transfer functions of ultrasonic transducers under different temperatures are imitated according to Mason equivalent circuit. The relevant experiments are carried out. The results show that the transfer characteristic of ultrasonic transducer varies with temperature and pressure. Therefore, we present an approach to correct the amplitude spectra of ultrasonic echoes got in different temperature and pressure environmeots. The theoretical simulation and experimental results prove that the approach is simple, effective and practical. 展开更多
关键词 Temperature and pressure characteristics of ultrasonic transducer and the amplitude spectra correction of echoes
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An executive review of sludge pretreatment by sonication 被引量:6
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作者 Ngoc Tuan Le Carine Julcour-Lebigue Henri Delmas 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第11期139-153,共15页
Ultrasonication(US), which creates hydro-mechanical shear forces in cavitation, is an advanced technology in sludge pretreatment. However, there are many factors affecting the efficacy of cavitation and ultrasonicat... Ultrasonication(US), which creates hydro-mechanical shear forces in cavitation, is an advanced technology in sludge pretreatment. However, there are many factors affecting the efficacy of cavitation and ultrasonication disintegration of sludge as a consequence.The objective of this work is to present an extensive review of evaluation approaches of sludge US pretreatment efficiency. Besides, optimization methodologies of related parameters,the differences of optimum values and the similarities of affecting trends on cavitation and sludge pretreatment efficiency were specifically pointed out, including ambient conditions,ultrasonic properties, and sludge characteristics. The research is a prerequisite for optimization of sludge US pretreatment efficiency in lab-scale and practical application. There is not-yet a comprehensive method to evaluate the efficiency of sludge US pretreatment, but some main parameters commonly used for this purpose are degree of sludge disintegration, proteins,particle size reduction, etc. Regarding US parameters, power input PUS, intensity IUS, and frequency FSseem to have significant effects. However, the magnitude of the effect of PUSand probe size in terms of IUShas not been clearly detailed. Investigating very low FSseems interesting but has not yet been taken into consideration. In addition, static pressure effect has been marginally studied only and investigation on the effect of pH prior to US process has been restricted. Their effects therefore should be varied separately and simultaneously with other related parameters, i.e. process conditions, ultrasonic properties, and sludge characteristics, to optimize sludge US pretreatment process. 展开更多
关键词 ultrasonic pretreatment Waste activated sludge Sludge disintegration Acoustic frequency Intensity effect pressure effect
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