• 한국수산과학회지
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• 제54권6호
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• pp.1036-1044
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• 2021

A linear array acoustic transducer with 12 tonpilz elements mounted independently on a gradual wedge-shaped tail mass was fabricated, tested and analyzed. The compensated transducer, which is modified by including a series inductance of 137 µH in the developed linear array transducer, attained improved figure of merit (FOM) performance characteristics compared with the uncompensated transducer. The four resonant frequency bands were identified from the measured FOM curve. The FOM response patterns over the frequency ranges of 31 to 40 kHz and 50 to 60 kHz were relatively uniform, whereas sharp resonance peaks were observed at around 73 kHz and 84 kHz. These results indicate that the developed linear array transducer can be used as an enhanced broadband transducer of echo sounder, and the operating frequency can be selected for more effective echo surveys in the fishing ground.

• 대한수의학회지
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• 제25권1호
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• pp.33-40
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• 1985

The inhibitory action of oxymetazoline on the spontaneous movements of isolated intestinal strips of the rabbit and the effects of antagonists upon the oxymetazoline actions were assessed with recordings through both isometric and isotonic transducers, and comparisons were made between both methods of recording. There were significant differences between the slopes of regression equations calculated from log dose response curves of oxymetazoline obtained from jejunum and those from ileum. But no difference was noted between both recordings either through isotonic transducer or through isometric transducer. The $ID_{50}$ of oxymetazoline obtained from the recording through isotonic transducer was $6.31{\times}10^{-7}M$ in jejunum and $3.16{\times}10^{-8}M$ in ileum. The recording through isometric transducer gave the values of $5.01{\times}10^{-7}M$ in jejunum and $1.07{\times}10^{-8}M$ in ileum. The $pA_2$-values of prazosin to oxymetazoline calculated from the recording through isotonic transducer were 8.13 in jejunum and 8.31 in ileum and the recording through isometric transducer gave the values of 7.29 and 8.26 in jejunum and ileum, respectively. The $pA_2$-values of phentolamine to oxymetazoline obtained from the recording through isotonic transducer were 8.18 in Jejunum and 9.31 in ileum and those from the recording through isometric transducer were 7.75 and 8.13 in jejunum and ileum, respectively. These results indicate that there are no significant differences between recordings either through isotonic transducer or through isometric transducer in assessing inhibitory responses of intestinal movement to certain drugs.

• 한국멀티미디어학회논문지
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• 제23권8호
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• pp.1040-1048
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• 2020

In this study, in order to improve the implantable bone conduction transducer of the prototype proposed by Shin et al., the effect of the element parameters of the transducer on the frequency characteristics was analyzed using electromagnetic and mechanical vibration analysis. Electromagnetic analysis was performed on the size of the permanent magnet and the distance between the metal plate and the coil to derive an optimal structure that generates the maximum Lorentz force. In addition, mechanical vibration analysis was performed on the cantilever structure of the vibrational membrane in order to minimize the distortion of the transducer and to have a frequency characteristic suitable for conductive hearing loss compensation. The frequency characteristics of the transducer of the optimal structure derived through finite element method were compared with the simulation results of the previous transducer. As a result, the output magnitude (displacement) of the transducer designed with the optimal structure generated an average 8.8 times higher than the previous transducer, and the resonance frequency was generated at 0.9 kHz.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.424-431
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• 2008

Recently, it is required that acoustic transducers for underwater detection and communication sensor have wide bandwidth and low operating frequency. In this research, the new acoustic transducer is proposed. This transducer is tonpilz type, and made of 1-3 piezoelectric composites as a driving parts. The developed transducer is evaluated the TVR(transmission voltage response) and RVS(receiving voltage sensitivity) characteristics around $4{\sim}14\;kHz$ frequency range and is compared to conventional tonpilz transducer made of solid piezoelectric ceramics as a driving parts. The resonance frequency of the developed transducer is decreased by 30% and the -3 dB bandwidth is increased by 90%, compared to conventional transducer with same dimensions. The value of TVR is decreased by 9 dB and The value of RVS is the same at resonance frequency.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.218-223
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• 1999

A piezoelectric flextentional deep-water sonar transducer has been simulated using a coupled FE-BEM. The dynamics of the sonar transducer is modelled in three dimensions and is analyzed with extern리 electrical excitation conditions as well as external acoustic pressure loading conditions. Different results are available such as steady-state frequency response for RX and TX, displacement modes, directivity patterns, back-scattering patterns, resonant frequencies, bandwidths, quality factors, transmitting voltage (TV) responses, input receiving sensitivity (RS) responses. White the present barrel-stave typed sonar transducer of the piezoelectric material is being simulated, the external surface of the transducer is modified in order to allow the same water pressure to be applied to the inner and the outer surfaces of the transducer. With this modification for deep-water application, the resonance frequency of the modified flextentional sonar transducer becomes much lower than that of the unmodified flextentional sonar transducer. The results of the present sonar transducer modelling are also compared with those of a commercial package such as ATILA.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.131-136
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• 2008

The transducer for multi-directionally movable ultrasonic motor having lambda shaped vibrators has been proposed and designed. The two branches cross at a right angle with each other at the tip. FEM analyses of lambda shaped transducer were carried out to find vibration modes for ultrasonic motor. The lambda shaped transducer has one symmetric mode and two anti-symmetric modes. The symmetric mode generates the normal direction motion of the tip. The lateral and vertical direction motion of the tip are excited by two anti-symmetric modes. The normal and lateral direction motions made an lateral elliptic trajectory. And the normal and vertical direction motions made an vertical elliptic trajectory normal to previous one. The transducer with 1 mm in thickness and 25 mm in length has been fabricated and evaluated. The resonance frequencies of the transducer was 32 kHz and 103 kHz. The tangential and vertical vibration displacement of the transducer having the lateral elliptic trajectory were $1.5{\mu}m\;and\;1.1{\mu}m$, respectively at the driving voltage of 100 Vpp and frequency of 32 kHz and 103 kHz. And the tangential and vertical vibration displacement of the transducer having the vertical elliptic trajectory were $0.4{\mu}m\;and\;0.2{\mu}m$, respectively at the same driving condition.

• 한국전기전자재료학회논문지
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• 제21권12호
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• pp.1063-1070
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• 2008

The performance of an acoustic transducer is determined by the effects of many design variables, and mostly the influences of these design variables are not linearly independent of each other. To achieve the optimal performance of an acoustic transducer, we must consider the cross-coupled effects of the design variables. In this study, the variation of the performances of underwater acoustic transducer in relation to its structural variables was analyzed. In addition, the new optimal design scheme of an acoustic transducer that could reflect not only individual but also all the cross-coupled effects of multiple structural variables, and could determine the detailed geometry of the transducer with great efficiency and rapidity was developed. The validation of the new optimal design scheme was verified by applying the optimal structure design of a flextensional transducer which are the most common use for high power underwater acoustic transducer. With the finite element analysis(FEA), we analyzed the variation of the resonance frequency, sound pressure, and working depth of a flextensional transducer in relation to its design variables. Through statistical multiple regression analysis of the results, we derived functional forms of the resonance frequency, sound pressure, and working depth in terms of the design variables. By applying the constrained optimization technique, Sequential Quadratic Programming Method of Phenichny and Danilin(SQP-PD), to the derived function, we designed and verified the optimal structure of the Class IV flextensional transducer that could provide the highest sound pressure level and highest working depth at a given operation frequency of 1 kHz.

• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.755-759
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• 2013

A broad-band underwater acoustic transducer that uses thickness vibration mode, derived from a disk type piezoelectric ceramic, has been proposed and designed for DVL (Doppler Velocity Log). Three different types of acoustic transducer were evaluated with respect to the transmitting voltage response, receiving voltage sensitivity and bandwidth of the transducer. The effect of the acoustic impedance matching layer and backing layer is discussed. The results demonstrated that three matching layer with lossy backing layer is the best configuration for underwater transducer. The trial underwater acoustic transducer with three matching layer has a frequency bandwidth of 55%, maximum transmitting voltage response of 200 dB and a maximum receiving voltage sensitivity of -187.3 dB.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.87-90
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• 1995

When the ultrasonic transducer operating at l MHz for use in cleaning semiconductor wafers or other industsrial materials is driven from the MOS-FET DC-to RF inverter, the output power severely depends on the frequency of operation since the quality factor of the transducer is high. In order to tune to the eresonating frequency of the ultrasonic transducer, the drive signal frequency of the MOS-FET power inverter is automatically scananed until the frequency is set at the resonating frequency of the ultrasonic transducer is maximized. The control circuit consists of an output power sensing circuit, a PLL controller, a frequency standard, and other peripheral circuits. The operation was satisfactory when the transducer having an output of 600 W at 1 MHz was used.

• 한국수산과학회지
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• 제52권6호
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• pp.702-708
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• 2019

The range resolution of echo sounders can be improved by enhancing the transducer bandwidth. We designed a bandpass matching network for expanding the bandwidth of a transducer by scaling in both impedance and frequency after transforming a lowpass network into a bandpass configuration for a third-order Bessel filter. We measured the effect of the Bessel matching network for a 50 kHz sandwich type transducer on the transmitting voltage response (TVR), receiving sensitivity (SRT) and figure of merit (FOM), using a chirp echo sounder system. Both the simulation and experimental results indicated that the transducer with a bandpass matching network was capable of producing a symmetrical acoustic output over a wider bandwidth (8.25 kHz) than was the transducer without a matching network (3.75 kHz). By implementing the Bessel matching network, we achieved a 120% bandwidth enhancement.