• 한국전기전자재료학회논문지
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• 제21권1호
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• pp.49-52
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• 2008

In this study, multilayer structured ultrasonic linear motor was simulated using Atila for investigating its optimum driving conditions. The ultrasonic linear motors mainly consist of an ultrasonic vibrator to generate elliptical displacement. The ultrasonic linear motor simulated in this paper was the use of the 1st longitudinal(Ll) and 4th bending vibrations (B4). Whit the increase of the number of piezoelectric actuator layers, displacement of node was increased. Maximum total displacement of node was about $3,91{\mu}m$ at the 13 layered ultrasonic motor under 5 V.

• Tribology and Lubricants
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• 제19권5호
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• pp.285-291
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• 2003

Ultrasonic vibrator is an equipment which atomizes and homogenization the oils by breaking the oil particles with ultrasonic cavitation, and would improve the properties. The present study deal with the ultrasonic breaking systems which recycle the shipborne waste oil into usable oil to be burnt. The first place, experimental studies were carried out to investigate the homogenizing effect of the waste oils by ultrasonic cavitation. Variation of the properties(viscosity, specific gravity and pH) and the matrix structures for the various shipborne waste oils were interpreted to analyse the breaking, dispersion effects by ultrasonic cavitation. The experimental results can be useful to the development of waste oil disposing systems.

• Tribology and Lubricants
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• 제9권1호
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• pp.55-61
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• 1993

Recently, due to the erosion damage that were generated increasingly at alloy metals of slide bearing by cavity of lubricating oil with tendency of high speed and high output of reciprocating engine, there is a need to study the process on the formation of cavitation erosion, and the characteristic of cavitation erosion at lubricating oil environments under various condition for marine ship. Therefore, the apparatus of cavitation erosion experiment used 20 KHz, $24 \mu m$ piezoelectric vibrator. The main results obtained through this test method are as follows: 1. The max. erosion rate at lubricating oil environments was related to the change of space, oil film thickness, and shown to tendency of gear oil>system oil>turbine oil>mixed oil environments with different viscosity. 2. The pitted hole by cavitation erosion at high viscosity oil environments became small and deep, and in addition to, they appeared to be wide and shallow at low viscosity.

• Tribology and Lubricants
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• 제11권1호
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• pp.58-65
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• 1995

When marine lubricating oil began to be emulsified and oxidized through ingressive water that have leaked from cooling pump seal systems, cooler, purifier system and piping system, the cavitation erosion-corrosion in alloy metals of bearings remains to the various troublesome problem at effective engine performance. Therefore, applied the cathodic protection to the control test of cavitation erosion-corrosion, and appointed the marine system oil containing 3% sea water as test environments, with different conductibility. Also, used the piezoelectric vibrator with 20 KHz, 24 $\mu$m as the cavity generation apparatus, and examined the weight loss, potential value, current density etc. in specimens with those condition. According to this testing data, investigated influence of cathodic protection on the control characteristics of cavitation erosion-corrosion, and will serve those as an elementary design data of marine bearing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.101-104
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• 2000

Milli-structure components are classified as component group whose size is between macro and micro scale. that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In order to conventional metal forming, where numerical process simulation is already idly applied, the micro-forming process is characterized by some scale effects which have to be considered in an advanced process simulation. milli-structure rectangular cup drawing is analyzed and designed using the finite element method and experiment. The result of the finite element analysis is confirmed by a series of experiment.

• 제어로봇시스템학회논문지
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• 제11권11호
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• pp.943-949
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• 2005

For the psychophysical experiment of tactile perception of shapes, experimental system consists of vibrator, tactile stimulation array, measurement and control system is designed and prepared. The psychophysical experiment for the tactile perception of shape is carried out by the estimation of the subject group. Through the experiment the threshold of tactile perception to multi-stimuli with some line shape is obtained. Also the appropriate tactile stimulus intensity and frequency of the tactile stimulation array to recognize arbitrary shapes effectively are derived and discussed.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1997년도 영남지회 학술발표회 논문집 Acoustic Society of Korean Youngnam Chapter Symposium Proceedings
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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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.627-630
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• 2004

Transducer for linear ultrasonic motor with symmetric and anil 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. Elliptical trajectoric of transducer was analyzed by employing the finite element method. From these results, the ultrasonic motor was fabricated and was measured for characteristics. In this paper compared an ANSYS analysis with an experiment results. The no-road maximum speed was 113.1[cm/s].

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.630-633
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• 1997

Spent fuel decladding device and dry voloxidizer is to separate the spent pellet from spent fuel rod cut by 250mm and to convert the spent pellet into powder form for reuse and/or disposal of the spent fuel. There are two methods in decladding and voloxidation of spent fuel, that is, wet method with chemical material and dry method with mechanical device. In this study, to examine the fuel rod decladding process and the pellet voloxidation process, the devices for the spent fuel decladding and the pellet voloxidation with dry method are developed. The decladding machine is designed to separate pellets from fuel rod by slitting device. And, the voloxidizer is designed to convert the spent pellet which is ceramic form into powder form by oxidation using the multi step mesh, vibrator, and air in the high temperature environment. The result of this study, such as operation condition et., will be utilized in the design of the machine for demonstration.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1087-1090
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• 2003

In this study, experimental procedures were suggested to investigate the sloshing behavior of a liquid storage tank subjected to inevitably external vibrating conditions. For this purpose. liquid storage tank with rectangular cross section was made of an acrylic resin for the visualization of liquid fluctuation. A specially designed vibrator was used to provide a specified vibrating condition to the liquid storage tank. Extrapolation technique was applied to determine sloshing natural frequency by using various sloshing frequencies at each vibrating displacement and liquid contents at a fixed vibrating frequency. Sloshing mode was also determined from continuous images or liquid fluctuation captured from a video camera. In addition, change in the height of the liquid free surface was measured by using a floating target and a laser displacement sensor. It is found that the suggested method can be applicable to identify the sloshing behavior of liquid storage tank with rectangular cross section.