• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기설비전문위원
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• pp.243-244
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• 2008

The Velocity Autocorrelation Function (VAF) of the sodium ions is calculated for a range of temperature from 250K to 1000K and converted into the linear ac-conductivity and ac-susceptibility response via Fourier transformation. A peak is found in the conductivity around $6{\times}10^{12}Hz$ that has some of the character of a Poley absorption. Here it is shown to be due to an harmonically coupled site vibrations of the sodium atoms, which extend only over a limited range. At frequencies below the peak the conductivity tends towards a constant i.e. dc value corresponding to a constant flow of ions through the simulation cell. At high temperatures the conductivity due to this ion transport process behaves like a metal with an insulator to metal transition occurring around a specific temperature.

• 한국세라믹학회지
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• 제24권6호
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• pp.527-536
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• 1987

PLZT ceramics of composition La/Zr/Ti=X/65/35(X=5-10 at.%) were fabricated by two state sintering technique.Transparent PLZT ceramics were obtained in the composition above 8 at. % La. Variations of electrooptic properties in the compositions between 8 at. % and 9 at. % La were able to be expected from the significant differences of P-E hysteresis curve and the changes of dielectric phase transition. The range of birefringence of 8/65/35 specimen was 4.08${\times}$10-3. Domain switching of 9/65/35 specimen was agreed with the applied electric pulse because input pulse signal corresponds to optical pulse response.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.999-1002
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• 2003

Electrooptical (EO) characteristics of a new multidomain vertical-alignment (MVA) liquid crystal display (LCD) with negative dielectric anisotropy on a homeotropic photopolymer were studied. Good voltage-transmittance (V-T) curves of the new MVA-LCD on the homeotropic photopolymer were obtained. Also, the stable response time of the new MVA-LCD on the homeotropic photopolymer was achieved. The viewing angle of the new MVA-LCD could be improved by a crossed stripe grating-groove surface as the alignment layer using a photolithograph method on the photopolymer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1472-1473
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• 2008

Polyimide thin films were cured locally using MEMS microhotplates. The polyimide locally cured at temperature over 350$^{\circ}C$ for 1 hour was fully cured. There was no significant difference between polyimide thin films cured in a conventional convection oven and those cured locally on MEMS microhotplates. The locally cured polyimide humidity sensor showed a linearity of 0.9995, a sensitivity of 0.77 pF/%RH, a hysteresis of 0.6 %RH, and a response time of 3s. These results indicate that the locally-cured polyimide films may be used as dielectric material of high speed, highsensitivity humidity sensors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1406-1407
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• 2008

In this paper, a micro balanced filter in magnetically coupled LC resonators is proposed, designed, simulated by using FR-4 PCB substrate for low cost, small volume IEEE 802. 11a wireless LAN application. Two pair of coupled LC resonators using magnetic coupling of embedded inductors are applied to obtain bandpass transmission response and improve their phase and magnitude imbalance characteristics. In addition, high dielectric composite film is applied to fabricate the high Q MIM capacitors with small size and high capacitance density. It has an insertion loss of 1.4 dB, a return loss of 10 dB, a phase imbalance of 0.25 degree, and magnitude imbalance of 0.17 dB at frequency bandwidth of 200 MHz ranged from 5.15 GHz to 5.35 GHz, respectively. The proposed balanced filter has a small volume of $1.1mm{\times}1.3mm{\times}0.6mm$ (height).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.471-474
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• 2002

Three-ring types liquid crystalline compounds having fluoro and isothiocyanate substituent were synthesized and their physical and electro-optical properties were measured to evaluate the applications to active matrix VA liquid crystal displays. The tetrakis(triphenylphosphine)palladium(0) catalyzed cross coupling of aryl boronic acids with aryl halides is used to prepare trans-4'-Alkoxy-2,3-difluoro-3'-isothiocyanato-4-(4-alkylcyclohexyl}-biphenyl series. The synthesized compounds showed the nematic liquid crystalline phase and the negative dielectric anisotropy. The prepared mixtures showed faster response time and lower threshold voltage than their host mixture.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.511-513
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• 2002

Electro-optical characteristics of new multi-domain vertical-alignment (MVA) liquid crystal displays (LCDs) with negative dielectric anisotropy on a homeotropic photopolymer were studied. Good voltage-transmittance (V-T) curves by the new MVA-LCD on the homeotropic photo-polymer were obtained. Also, the stable response time of MVA-LCD on the homeotropic photopolymer can be achieved. The viewing angle of the new MVA-LCD could be improved by the grating groove with UV exposure and development on the photo-polymer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.72-74
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• 2014

Multilayer ceramic capacitor (MLCC) makes acoustic noise of electronic devices. Conversed piezoelectric effect of dielectric substance consists of $BaTiO_3$ causes vibration of MLCC so it must be analyzed to reduce the noise. Thus, finite element model for piezoelectric analysis of MLCC was constructed in this paper. Piezoelectric characteristics of MLCC was considered for the accurate simulation result. Displacement response for sinusoidal voltage signal was measured and simulation result was verified with test result.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.558-561
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• 2005

In-situ photopolymerization of alkyl acrylate monomers in the presence of a nematic fluid provides a cellular matrix of liquid crystalline droplets in which the chemical structure of the encapsulating polymer exerts control over the alignment (anchoring) of the liquid crystalline molecules. Control is obtained by variation of the alkyl side chains and through copolymerization of two dissimilar monofunctional acrylates. Two monofunctional acrylates with opposing tendencies on copolymerization provide control over the tunability of anchoring over a wide temperature range. Using various acrylates we show that a uniform vertical alignment can be achieved over a large area. Utilizing this technique and a nematic with negative dielectric anisotropy, we have fabricated highly flexible liquid crytal based devices, with high contrast and fast response time, without using any alignment layer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1794-1797
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• 1997

The preflashover light emission of the $SiO_2$-dielectric system behavior under high electric field is discussed. Time dependence of the voltage drop, electrical current, and light emission, are analyzed for high-purity $SiO_2$-vacuum systems under impulse voltage stress. We will summarize the experimental results showing the main feature of the time-dependent system response up to breakdown.