• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.292-295
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• 2002

Transducer for linear ultrasonic motor with symmetric and anti-symmetric modes was studied. The transducer was composed of two Langevin-type vibrators that cross at right angles with each other at tip. In order to excite two vibration modes, two Langevin-type vibrators must have 90-degree phase difference with each other. As a result, tip of transducers moves in elliptical motion. In this paper, elliptical trajectory of transducer was analyzed by employing the finite element method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.33-36
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• 1998

This paper is a study on a linear ultrasonic motor with a first longitudinal$(L_1)$ and fourth bending $(B_4)$ double-mode rectangular plate. The stator vibrator is composed of an elastic material plate and of a piezo-ceramic element having a motion by electrical excitation. Each strain vector differs by $90^{\circ}$ generate travelling wave with the elliptical displacement motion of a point on the surface. To magnify displacement of longitudinal direction in elliptical displacement motion, the motor has a mechanism of the.displacement enlargement. In this paper, the vibration shape of the stator is simulated using the finite element method. A detailed model considered of the piezoelectric effect and of the exact geometry of the stator is used to calculate the displacement. The position of displacement mechanism is decided by the maximum displacement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.664-668
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• 2003

Transducer for ultrasonic linear motor with the symmetric and anti-symmetric modes was studied. The ultrasonic linear motor consists of two Langevin type piezoelectric vibrators that cross at right angles with each other in tip. In order to excite symmetric and anti-symmetric modes, the transducer must have a phase shift of 90 degree in space and time. Therefore, the tip of transducer moves on an elliptical motion. In this paper, the finite element analysis was used to optimize dimension and displacement of the transducer. The ultrasonic motor was fabricated using the simulated result and the driving characteristics were measured. No-load velocity was 0.28[m/s] and the maximum efficiency was 30[%] in resonance frequency.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.75-80
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• 2013

Single crystal sapphire being used in high technology industry is a brittle material with a high hardness and excellent physical properties. ELID(Electrolytic In-Process Dressing) grinding technology was applied to material removal machining process of single crystal sapphire wafer. Ultrasonic vibration which added to material using ultrasonic table was adopted to efficient ELID grinding of sapphire materials. The evaluation of the ground surface of single crystal sapphire wafer was carried out by means of surface measuring by using AFM(Atomic Force Microscope), surface roughness tester and optical microscope device. As the results of experiment, it was shown that more efficient grinding was conducted when using ultrasonic table. In case of using #170 grinding wheel, surface roughness of ELID ground specimen in using ultrasonic table was superior to ELID ground specimen without ultrasonic table. However, In case of using #2000 grinding wheel, surface roughness of ELID ground specimen in using ultrasonic table was inferior to ELID ground specimen without ultrasonic table.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1720-1722
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• 1999

In this paper, we studied the properties of small-size disk-type ultrasonic motor using travelling wave for the application to the precise control robotic joint motor and fabricated it. The diameter of the ultrasonic motor fabricated was 13mm. Also, the piezoelectric vibrator was constructed by piezoelectric ceramic and elastic material. The piezoelectric ceramic was composed to PZ-PT-PMN which was shown the high electromechanical stability under high vibration level and stainless steel was used as the elastic material in which configuration was disk-type. To conform the capability of application to robotic motor, we measured the change of rotational speed according to applied voltage and applied frequency. As the results, the small-size disk-type ultrasonic motor was able to fabricate, and the revolution speed was 350 [rpm] when input voltage was 55 [Vrms] and applied frequency 160.4 [kHz] under pre-load.

• Tribology and Lubricants
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• v.22 no.4
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• pp.218-224
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• 2006

The sludge oils were produced necessarily in the ships operation, so that it will be the best way to manage the sludge oils inside ship itself from a viewpoint of the prevention of marine oil pollution. The ultra-sonic breaking system which recycle the sludge oil from ship into usable oil to be brunt is recognized as a most possible recycling device. In this regards, the purpose of this study is to examine erosion damage,on the SS400 specimen by cavitation and the effect of impact pressure generated from the demolition of the cavity of ultrasonic vibration in the marine sludge oil environment.. The erosion damage of specimen was investigated mainly on weight loss, weight loss rate and maximum erosion rate with variation of the oil temperature as well as the change of space between transducer hem and specimen. The experimental results showed that as the space between ultrasonic vibrator horn and specimen disk increased, the weight loss and weight loss rate decreased and the values were larger in SFO than in SLO. The experimental results can be useful to the development of sludge oil disposing systems and to consider a countermeasure for the prevention of erosion damages by cavitation.

• Mass Spectrometry Letters
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• v.10 no.4
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• pp.103-107
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• 2019

Low-temperature plasma (LTP) ionization is one of the ambient ionization methods typically used in mass spectrometry (MS) for fast screening of chemicals with minimal or no sample preparation. In spite of various advantages of LTP ionization method, including simple instrumentation and in-situ analysis, more general applications of the method are limited due to poor desorption of analytes with low volatilities and low ionization efficiencies in the negative ion mode. In order to overcome these limitations, an ultrasonic vibrator of a commercial hand-held humidifier was interfaced with an LTP ionization source, which generated microdroplets from sample solutions and assisted with LTP ionization. Ionization behaviors of various chemicals in microdroplet-assisted LTP (MA LTP) were tested and compared with typical LTP ionization from dried samples applied on a surface. MA LTP efficiently ionized small organic, amino, and fatty acids with low volatilities and high polarities, which were hardly ionized using the standard LTP method. Facile interaction of LTP with ultrafine droplets generated by ultrasonic resonator allows efficient ionization of relatively non-volatile and polar analytes both in the positive and negative ion modes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.4
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• pp.335-340
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• 2008

In this study, novel structured thin ultrasonic rotary motor has been proposed. Ultrasonic motors are based on an elliptical motion on the surface of elastic body. Thin brass plate was used as a cross shaped vibrator and eight ceramic plates were attached on upper side and bottom side of the brass plate. From the thin stator, elliptical displacements of the four contact tips were obtained. To find the optimal size of the stator, motions of the motors were simulated using ATILA by changing length, width and thickness of the ceramics. The stators had commonly three resonance peaks and contact tips of the stator moved on tangential or normal trajectories at these resonance peaks. The maximum displacements at the resonance peaks were compared. As results, maximum displacements of the contact tips were obtained at the length of 16 mm, width of 6 mm and thickness of 0.4 mm. Changes of the resonance frequencies were inversely proportional to the length of ceramic and proportional to the width of ceramic. The motor was fabricated by using the designed stator. And, the characteristics of the motor were compared with the simulated results. When the motor was fabricated with these results, speed fo 935 rpm was obtained by input voltage of 25 Vrms at 93.5 kHz.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.12
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• pp.1310-1315
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• 2006

This study examines algae removal and reduction using ultrasonic. Experiments were carried out on frequency: 28 kHz single-wave, 40 kHz multi-wave; intensity: 10, 15, 20, 25, 30 W/L; algae concentration: 500, 1000, 1700/ml; exposure time: 1, 3, 5, 7, 10, 15, 20 min. Also, We investigated algae removal and reduction in single cistern where raw water including algae was directly exposed to ultrasonic and in the double cisterns located in 4 cm from ultrasonic vibrator. The algae type used in this study was Melosira genus of Bacillariophceae. The Bacillariophceae is the representative algae which causes blockage of filter basin. Because of its resistance against oxidizers, it flows into the filter basin after sterilization. As a result of this study, the form of Bacillariophceae was completely destroyed and dissolved after the application of ultrasonic waves unlike the sterilization using oxidizers. Removal efficiency of algae using ultrasonic waves increased in proportion to intensity and exposure time of ultrasonic waves, and in double cisterns is better than single cistern.

• Proceedings of the Acoustical Society of Korea Conference
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• 1997.06a
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• pp.40-43
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• 1997

It is known tat the echoes from the most objects differ from the incident pulses in amplitude and frequency .Especially, the frequency in echoes from moving target is shiftby the Doppler effect. it causes to reduce the receiving sensitivity of piezoelectric transducers that have definite band width. The electric impedance, whichis connected to the electrical terminals, notably changes the resonant frequency of a thickeness mode piezoelectric vibrator with high electromechanical doupling due to the electroelastic effect. Using this effect, we have developed a frequency controllable ultrasonic transducer which is mad eof multi-layered PZT disks to adjust to frequency shifted by Doppler effect. The characteristics of transducer can be obtained by using the equivalent circuit of transmission line model. It was confirmed experimentally that the center frequency and band width of the trasducer could be controlled by the conditions of the electrical terminals. These results coincided with theoretical results.