• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.378-381
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• 2003

제작 장치와 공정이 간단하고, 두께제어 및 다양한 종류와 형태의 후막제작이 가능하며, 경제적 효율성과 기술적 장점을 가지고 있는 전기영동전착방식으로 산화물계 고온 초전도 후막을 제작하였다. 전착특성을 개선하기 위하여 측면보조전계 인가 방식을 설계, 적용하였다. 측면보조전계 인가 방식의 전기영동전착법을 적용함으로써, 기존의 단독 전착전계 인가방식에 비하여 전기영동전착 후막의 표면 균일성을 확보할 수 있음으로 임계전류 밀도를 향상시킬 수 있었다. 그러므로 측면보조전계 인가방식은 전기전자, 의료, 기계 분야의 핵심 산업 및 첨단 소재의 응용분야에 이르기까지 매우 폭넓은 범위에서 효과적으로 적용될 수 있을 것으로 사료된다. 특히 후막제작이 어려운 세라믹계열에의 적용이 가능하며, CRT 튜브의 전자총 히터코일과 같은 특수 제작조건을 비롯하여 균일하고 치밀한 막의 제작이 요구되는 기술공정상의 목적이 유사한 경우의 여러 가지의 응용 대상에도 적용함으로써, 그 특성과 성능을 향상시킬 수 있을 것으로 판단된다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.593-601
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• 2012

Ordered mesoporous oxide films have been focused because of their low density, high interior specific surface area, and high thermal insulation. Specially, the ordered mesoporous oxide films prepared by self-assembly has many advantages due to easy process and high reproducibility. In this work, ordered mesoporous $SiO_2$, $Al_2O_3$, and $TiO_2$ films were synthesized by control of composition and processing parameter. Also, their structural, thermal, and mechanical properties were characterized variously. In conclusion, ordered mesoporous oxides will be one of core materials in new technology due to their excellent and unique properties.

• Electrical & Electronic Materials
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• v.6 no.6
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• pp.573-581
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• 1993

0.10Pb(Sb$_{1}$2/Sn$_{1}$2/)O$_{3}$-0.25PbTiO$_{3}$-0.65PbZrO$_{3}$ 세라믹을 소결온도 및 시간을 각각 1200-1250[.deg.C]에서 2, 4, 6시간으로 변화시켜 제작하였으며 시편의 소결조건 및 MnO$_{2}$(0~0.30mol%)첨가량에 따른 잡음특성을 관찰하였다. 초전계수 및 전압감도는 1250[.deg.C]에서 2시간 소결시킨 시편에서 각각 3.49x$10^{-8}$[C/$cm^{2}$K], 147[V/W]의 최대값을 나타내었다. 초전형 적외선 검출기의 잡음특성에 있어 증폭기의 전류잡음 .DELTA.V$_{i}$가 총 잡음전압에 대해 지배적인 경향을 나타내었으며 MnO$_{2}$가 0.24[mol%] 첨가된 1250[.deg.C]에서 2시간 소결시킨 시편에서 가장 양호한 pop-corn잡음특성을 나타내었다.다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.381-384
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• 2001

The combined stirring method to uniform distribution of particle is consisted of two strring force both electro-magnetic stirring generated from induction heating and mechanical stirring with graphite stirrer. PMMC billets were fabricated with the volume fractions ranged from 0% to 20% and particle sizes ranged from 14$\mu\textrm{m}$ to 25$\mu\textrm{m}$. It is important to control the size of primary ${\alpha}$-AI solid particles because it could become the cause of the particle pushing or capture phenomena from the fact that secondary dendrite arm spacing size depends on the cooling rate during the solidification in hypoeutectic AI-Si alloy.

• Ceramist
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• v.23 no.1
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• pp.27-37
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• 2020

Recently, 4D printing technology has received considerable attention in various industries and research fields including soft robotics, tissue engineering, electronics. In 4D printing process, 3D printed object transforms itself into programmed structure by the input of external energy. Thus, this process requires not only smart materials, capable of changing their properties or features in response to external stimuli such as electricity, temperature, light, etc., but also smart structures, multi-material 3D printing, simulation and so on. In this review, the concept, technical elements and potential of 4d printing are presented.

• Ceramist
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• v.22 no.3
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• pp.218-229
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• 2019

The development of highly efficient thermally activated delayed fluorescence (TADF) materials is an active area of recent research in organic light emitting diodes (OLEDs) since the first report by Chihaya Adachi in 2011. Traditional fluorescent materials can harvest only singlet excitons, leading to the theoretically highest external quantum efficiency (EQE) of 5% with considering about 20% light out-coupling efficiency in the device. On the other hand, TADF materials can harvest both singlet and triplet excitons through reverse intersystem crossing (RISC) from triplet to singlet excited states. It could provide 100% internal quantum efficiencies (IQE), resulting in comparable high EQE to traditional rare-metal complexes (phosphorescent materials). Thanks to a lot of efforts in this field, many highly efficient TADF materials have been developed. This review focused on recent molecular design concept and optoelectronic properties of TADF materials for high efficiency and long lifetime OLED application.

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.27-34
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• 1995

The analysis of nonlinear equivalent circuit and the resonance characteristics of input current and output voltage were simulated, and their electrical properties are discussed in the transverse-type piezoelectric ceramic transformer. The nonlinear resonance characteristics of input current and output voltage showed by the thermal effect due to a higher driving current, the nonlinearity increased greatly as driving current increased. When load resistor was 100[M.ohm.], the nonlinear coefficient was -1.3. The nonlinear resonance curve of input current and output voltage for a variation of input voltage and load resistor agreed with the discussed theory. The output voltage increased nearly proportioned to input voltage when load resistors were below 50[M.ohm.], the voltage step-up ratio decreased when a load resistor was 100[M.ohm.] and their maximum value was 950.

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.35-39
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• 1995

After making the light modulator using the BLN-PZT 9.0/65/35 specimen which has the slim-loop hysteresis characteristics and quadratic electro-optic characteristics, switching and spectral response characteristics were investigated. As the results of switching characteristics of the light modulator, it was found that the transmitted light intensity was modulated by both AC and pulse voltage. From the possibility of the selective transmission of the RGB(Red, Green, Blue) spectrum with electric field, the application for the light modulator, light shutter and color filter was expected.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.255-261
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• 1997

In this study, pore-containing barium titanate ceramics were prepared with different porosities and pore sizes, in order to better understand how porosity and pore size affect electrical breakdown of barium titanate ceramics. A granulated barium titanate powder was mixed with three grades of commercial polymer microspheres up to 11wt%. The electrical breakdown test was performed at two different temperatures of 30.deg. C(below Tc) and 150.deg. C(above Tc) for samples immersed in a silicon oil bath using a 60kV de power supply. Electrical breakdown strength of pore containing barium titanate ceramics with porosity lower than 10% decreased as pore size and porosity increased. However, above the 10% porosity region, electrical breakdown strength decreased as the pore connectivity increased. From the experimental results, an optimum electrical breakdown model is proposed in an attempt to explain the effect of pores.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.182-183
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• 2008

본 연구에서는 유전 손실이 낮고, 고분자(LCP)의 유전율을 높이기 위하여 (100-x)LCP(polymer)-xNPO(ceramic) 복합체 (x= 0, 10, 20, 30, 40, 50)의 유전 특성 및 미세구조를 연구하였다. LCP와 ceramic filler(NPO)는 Brabender Mixer를 사용하여 $300^{\circ}C$에서 혼합한 후, Hot press 사용하여 $300^{\circ}C$, 7ton 성형 압력으로 pellet 형태 $(2.5cm\times2.5cm\times0.1cm)$로 제조 하였다. LCP-NPO 복합 소재를 SEM을 통해 미세구조를 관찰하였고, 복합체의 유전 특성을 조사하였다.