Michihisa Shiiba

Estimation of Cavitation Sensor with Hydrothermally Synthesized Lead Zirconate Titanate Film on Titanium Cylindrical Pipe: Spatial Distribution of Acoustic Cavitation Field and Basic Characteristics of Cavitation Sensor

We developed a small cavitation sensor by the deposition of a hydrothermally synthesized lead zirconate titanate (PZT) polycrystalline film on a Ti hollow cylindrical pipe. The spatial distributions of acoustic cavitation generated in a vessel of 150 kHz sonoreactor were measured by using our cavitation sensor. We estimated the spatial distribution of acoustic cavitation by using the broad band integrated voltage (BIV) calculated from the output signal of our cavitation sensor. A similar spatial distribution of the BIV to a sonochemical luminescence pattern could be observed in the measured results. Our fabricated cavitation sensor could be applied to the measurement of sound pressure in a high-intensity ultrasound field with acoustic cavitation for a period longer than 150 without damage. We measured the spatial distribution and directivity of the receiving sensitivity for the characterization of our cavitation sensor. It is suggested from the measured results that the BIV and the cavitation signal included in the output signal from the cavitation sensor are based on the acoustic cavitation generated in the cylindrical hollow of our cavitation sensor.

Frequency characteristics of receiving sensitivity and waveform of an anti-acoustic cavitation hydrophone

Novel anti-cavitation hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film on the back of a titanium plate. These hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound (HIFU) device. The hydrophones were designed using Masons equivalent circuit and by numerical simulation to improve their receiving characteristics for the measurement of the HIFU device. High receiving sensitivity with flat frequency characteristics was obtained by using a backing material with a specific acoustic impedance of about 20 × 106 kg/(m2 s) [Rayl]. We developed a new type of hydrophone using a tin and titanium rods as backing materials, which have specific acoustic impedances of 24 × 106 and 27 × 106 kg/(m2 s), respectively. The fabricated anti-cavitation hydrophone showed wide frequency characteristics of the receiving sensitivity. Furthermore, we observed the output waveform with distortion due to nonlinear propagation using the fabricated anti-cavitation hydrophone. This hydrophone was not damaged by exposure to a high-intensity acoustic field of an ultrasound cleaner under acoustic cavitation for duration of about ten times longer than the conventional commercial hydrophone.

Micro-particle manipulation by single beam acoustic tweezers based on hydrothermal PZT thick film.

Single-beam acoustic tweezers (SBAT), used in laboratory-on-a-chip (LOC) device has promising implications for an individual micro-particle contactless manipulation. In this study, a freestanding hydrothermal PZT thick film with excellent piezoelectric property (d33 = 270pC/N and kt = 0.51) was employed for SBAT applications and a press-focusing technology was introduced. The obtained SBAT, acting at an operational frequency of 50MHz, a low f-number (∼0.9), demonstrated the capability to trap and manipulate a micro-particle sized 10μm in the distilled water. These results suggest that such a device has great potential as a manipulator for a wide range of biomedical and chemical science applications.

Cavitation sensor with hydrothermally synthesized lead zirconate titanate polycrystalline film deposited on cylindrical titanium pipe: Estimation of acoustic cavitation field and basic characteristics of cavitation sensor

We have developed a small cavitation sensor by deposition of hydrothermally synthesized lead zirconate titanate polycrystalline film onto the outer surface of a hollow cylindrical titanium pipe. The spatial distribution of acoustic cavitation generated in the vessel of a 150 kHz sonoreactor was measured by using the broadband integrated voltage (BIV) calculated from the output signal of the cavitation sensor. A spatial distribution similar to the sonochemical luminescence pattern could be observed in the measured BIV results. We found that our fabricated cavitation sensor could measure the spatial distribution of acoustic cavitation in a high-intensity ultrasound field for a period exceeding 150 h without damage. We also measured the spatial distribution and directivity of the receiving sensitivity for characterization of the sensor. The measured results suggest that the BIV and cavitation signal included in the output signal of the cavitation sensor are a consequence of the acoustic cavitation generated ...

Characterization of hydrophone with hydrothermal PZT thick film vibrator and Ti front layer for measurement in high intensity therapeutic ultrasound

Acoustic characterization of high intensity therapeutic ultrasound (HITU) field is important for the accurate prediction of ultrasound induced bioeffects in tissue. In this paper, the robust designed needle type hydrophones were fabricated by the titanium front plate to withstand cavitation and by the deposition of a hydrothermally synthesized lead zirconate titanate (PZT) thick film vibrator on the opposite surface of titanium plate. Direct measurements of acoustic distribution profile at a focal region of the HITU probe driven continuous wave (CW) with input power to the sound source up to 50 W were performed. The tough hydrophone sensitivity responding to CW driven power range up to 50 W was measured in a tank of degassed water. The sensitivity was responding linearly up to about 8 MPa and not responding linearly acoustic pressure higher than 8 MPa, while the velocity of the vibration at the HITU probe was responding linearly up to driven power of 50 W. This 8 MPa was estimated in comparison with the standard hydrophone at driven power of 1 W to the sound source. We confirmed the linearity of responsivity of our hydrophone at high acoustic pressure. However, sensitivity of this hydrophone should be calibrated with higher acoustic pressure for higher acoustic power measurements. It is necessary to enable accurate characterization of HITU fields.

Cavitation sensor with hydrothermally synthesized lead zirconate titanate poly-crystalline film deposited on Ti cylindrical hollow pipe

A small cavitation sensor was developed in our laboratory by deposition of hydrothermally synthesized lead zirconate titanate poly-crystalline film on outer surface of Ti hollow cylindrical pipe. The spatial distributions of acoustic cavitation generated in a vessel of 150 kHz sonoreactor were measured by using our cavitation sensor. We estimated the spatial distribution of acoustic cavitation by using broad band integrated voltage (BIV) calculated from the output signal of our cavitation sensor. A similar spatial distribution of the BIV to a sonochemical luminescence (SCL) pattern could be observed in the measured results. Our fabricated cavitation sensor could be applied to the measurement for spatial distribution of acoustic cavitation in a high-intensity ultrasound field for a period longer than 100 hours without damage. We measured the spatial distribution and directivity of the receiving sensitivity for the characterization of our cavitation sensor. It is suggested from the measured results that the BIV and the cavitation signal included in the output signal from the cavitation sensor are based on the acoustic cavitation generated in the cylindrical hollow of our cavitation sensor.

Development of anti-cavitation hydrophone using a titanium front plate: Durability test in the high intensity focused ultrasound field

Our research group has developed new anti-cavitation hydrophones by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film with 15 μm thickness on the back surface of a titanium front plate with 50 μm thickness and 3.5 mm diameter. A durability test of the anti-cavitation hydrophone was performed when the anti-cavitation hydrophone under test was placed at the focal point of a concave focused ultrasound transducer with 100 mm diameter and at a resonant frequency of 1.75 MHz. The amplified 80 Vp-p (calculated electric input power: about 40 W) signal was applied to the concave ultrasound transducer at the focal point of the focused ultrasound system and high-intensity ultrasound waves were irradiated in water. The irradiated sound pressure at the focal point was about 4 MPa. Through this research, we will report that the fabricated new anti-cavitation hydrophone was robust and was not damaged easily, even in a high intensity focused ultrasound field with sound pressure of where...

Development of anticavitation hydrophone using a titanium front plate: Effect of the titanium front plate in high-intensity acoustic field with generation of acoustic cavitation

Novel anticavitation hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film at the back of a titanium front plate. These anticavitation hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound (HIFU) device. Their sensitivity was improved by approximately 20 dB over that of the conventional anticavitation hydrophone by modifying their basic structure and materials. The durability of the anticavitation hydrophone that we fabricated was compared by exposing it to a high-intensity acoustic field at the focal point of the HIFU field and in the water tank of an ultrasound cleaner. Therefore, the effect of the surface of the titanium front plate on acoustic cavitation was investigated by exposing such a surface to the high-intensity acoustic field. We found that the fabricated anticavitation hydrophone was robust and was not damaged easily, even in the focused acoustic field where acoustic cavitation occurs.

Durability test and observation on non-linear distortion in output waveform of anti-cavitation hydrophone in high intensity ultrasound

Novel anti-cavitation hydrophones were fabricated by depositing hydrothermally synthesized lead zirconate titanete polycrystalline film on the reverse surface of a titanium plate. These hydrophones were hard to be damaged by the measurement of the acoustic field formed by a high intensity therapeutic ultrasound (HITU) device. This hydrophone was not damaged by exposure to high-intensity acoustic field of ultrasound cleaner with generation of acoustic cavitation for about ten times longer than the conventional commercial hydrophone. The fabricated anti-cavitation hydrophone showed the wide frequency characteristics of the receiving sensitivity. Furthermore, we observed the output waveforms of the fabricated anti-cavitation hydrophone with distortion due to nonlinear propagation in water.

Study on cavitation sensor with hydrothermally deposited lead zirconate titanate film-Effect of integration range of BIV on the measured results

We developed small cavitation sensor with longer lifetime by the deposition of a hydrothermally synthesized lead zirconate titanate film on the outer surface of a hollow cylindrical Ti pipe. Our sensor could be applied to the measurement of sound pressure in a high-intensity ultrasound field with acoustic cavitation longer than 150 hours. We investigated the effects of integration range on the BIV (Broad band Integrated Voltage) images which were measured in a water vessel of a sonoreactor. We measured the spatial distribution of the cavitation generated in the water vessel of the 150 kHz sonoreactor by using our sensor. We estimated the spatial distribution of BIV calculated from the output signal of our sensor in various frequency ranges. Fundamental and harmonic components included in the driven ultrasound signal in the water vessel of the sonoreactor were decreased and disappeared sufficiently in the frequency range higher than 1 MHz. We reconstructed the images of spatial distribution of BIV with various integration ranges like 50 kHz-10 MHz, 100 kHz-10 MHz, 1 MHz-10 MHz. It was found that the spatial distribution image of BIV obtained in frequency range of 1 MHz-10 MHz was more similar to sonochemical luminescence image than that of other frequency ranges.