• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1179-1183
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• 2007

Electro-Active paper(EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, and which result in good correlation with each other.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1707-1709
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• 1999

Insulating thin films for strain gauge application, such as $SiO_2$ single layers and $SiO_2/Si_3N_4$ multilayers, are deposited by using both PECVD and RF magnetron sputtering techniques. Micro-structural analysis and electrical characterization are carried out on those films. It has been observed that PECVD films have a smoother surface and a denser micro-structure than sputter films. It should be also found out that the electrical insulation property of $SiO_2$ film can be significantly improved by adding the $Si_3N_4$ layer.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.687-692
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• 1999

A new technique to measure low level capacitance variations of the gyroscope is proposed and verified by computer simulation. It is based on the new CV(capacitance-voltage) converter circuit biased by dc current source and the peak detector without low pass filter. The CV converter biased by dc current source provides good signal-to-noise ratio and this setup of the detection circuitry without low pass filter makes it possible to provide short settling time, that is, higher speed of measurement and wide operation range if only a few parameters are adjusted. The key parameters that affect the performance of the detection circuitry are illustrated and computer simulation results are presented. The demonstrated detection circuitry shows linear response from 10 fF to 130 fF at 10 kHz and shows good linearity.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.196-201
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• 2000

It is very important not only to detect PD signal but also to locate PD source in power cable line including its accessories. In this paper, the PID localization technique using interruption of metal sheath of cable or accessory is described. By interruption of metal sheath, the polarity of PD pulse to be measured on each part can be compared. With this technique, the exact location of PD in the accessory which has some defects can be found. Although the 'Soft' interruption method, that is, cable sheath is divided by semi-conductive layer with the resistance of higher than 1 k$\Omega$, was used instead of 'Hard' interruption method, it is also possible to detect exact location of PD. This technique is considered to be very effective for detecting PD localization in the type test of cable and accessories.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.11
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• pp.508-514
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• 2005

In this paper, it was investigated the characteristics of PD(partial discharge) pulse shapes in oil and the possibility of TF(Time-Frequency) analysis for the discrimination of air corona in on-site PD measurement of oil transformers. For the purpose, single and multiple discharges combined with oil discharges and air corona were generated and measured by use of artificial models through the HFPD pulse detector and the oscilloscope. PD pulse shapes were different according to the type of defects, especially including air corona- pulses. Also, through the TF analysis, data clusters could be classified each other in the TF Map, even in the case of multiple discharges. Therefore, it is known that TF analysis could be aprlied for the improvement of on-site PD measurement in oil transformers.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2125-2127
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• 2004

In this paper, a DNA chip with a microelectrode array was fabricated using microfabrication technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5 end were immobilized on the gold electrodes by DNA arrayer. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 concentrated at the electrode surface through association with formed hybrid. It suggested that this DNA chip could recognize the sequence specific genes.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.4
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• pp.55-61
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• 1995

Variable structure control (VSC) can be used for the control of power plants required stability and robustness such as elevator control. It has no overshoot and is insensitive to parameter variations and disturbances in the sliding mode where the system structure is changed with the sliding surface in the center. But in the real system, VSC has a high frequency chattering which has a bad influence upon the control system proformances. In this paper, to alleviate the high frequency chattering, a binary controller (BC) with inertial type external loop is implemented by DSP and applied to position control of brushless DC motor. Binary controller has external loop to generate the continuous control input with the flexible variation of primary loop gain. Thus it has the property of chattering alleviation in addition to advantages of the conventional variable structure control.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1378-1381
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• 1995

Some interesting electrochemical characteristics of waterpen point-to-plate airgaps for dc and ac powers have been investigated at room atmosphere in a metal chamber. It is found that the ac discharge on the Pt point generated much ozone, while the negative do discharge on the waterpen point generated the highest ozone. And, the ac discharges of the waterpen point and the Pt point produced a little $NO_x$. But the dc discharge of the Pt point and waterpen point did not generated $NO_x$ anyway. As a result, it could be said that the water on the pen point acts something to generate ozone and $NO_x$ in room atmosphere.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.266-266
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• 2009

For the development of hybrid supercapacitor, increasing energy density is one of the most crucial matters. Since the energy density is the function of capacitance and voltage, it is necessary to enhance energy density for increasing capacitance or voltage. For the high working voltage, it was to enforce Li ion free-doping to activated carbon. As a result, initial capacitance has increased by 11% than raw cell. But capacitance has decreased by Li ion re-solution to electrolyte for increase the number of cycle.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.165-168
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• 2007

Electrooptic characteristics of Xe-type flat fluorescent lamps (FFL) have been investigated by using a Q-V Lissajous method. It was found that the luminance of the Mgo-coated FFL became more than doubled compared to normal FFLs operated at the same driving voltage, indicating the possibility of the efficacy improvement in the MgO-coated FFLs. Change in the driving condition, in particular, the duty ratio had effects on the electrooptic properties, and it was found that the duty ratio of 50% was the optimum condition from the viewpoints of the efficacy and the lamp voltage.