• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.633-638
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• 2009

Lightweight materials were fabricated using glass abrasive sludge, bottom ash and slag powder in this study. This study tried to draw the correlation between physical properties and internal pore of lightweight material. The content of bottom ash and slag powder was from 10% to 50% and firing temperature from $760{^{\circ}C}\;to\;800{^{\circ}C}$ in rotary kiln. The lightweight material containing bottom ash or slag powder had a specific gravity of $0.21{\sim}0.70$ at particle size $2{\sim}4$ mm. Replacement ratio of the admixture increasing with specific gravity increased. Fracture strength of panel made with various lightweight materials was $32{\sim}55\;kgf/cm^2$ and flexural strength was $11{\sim}18\;kgf/cm^2$. Fracture strength increased by 72% and flexural strength was 63% compared with reference. Thermal conductivities of panel was $0.07{\sim}0.11W/m{\cdot}k$. The water absorption ratios of panel with lightweight materials containing bottom ash were $1.8{\sim}2.8$% and slag powder were $2.65{\sim}2.8$%. Excellent results on resistant of water absorption.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.84-89
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• 2016

We present the results of a study of a piezoelectric generator that generates electricity by the application of tension to an element. A device is named "EYE-type generator". The EYE-type generator consists of a rectangular ceramic and two elastic body plates that are attached to upper and lower surfaces of a ceramic. If tension is applied to both ends of the elastic body, that tension is transformed to pressure on the ceramic through a change in the form of the elastic body, causing a piezoelectric effect whereby electricity is generated by the ceramic. This generator is relatively durable because a forces are not applied directly to the ceramic. We examined dependencies of the generator's output characteristics on the size of the ceramic and elastic body. A resonance and output characteristics were analyzed by using a finite element method. The generator was fabricated based on results of the analysis, and this was attached to a frequency-controllable vibrator to measure the output characteristics. The measured results were compared with results of the simulation, and the results pointed to the practicality of the design.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.12
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• pp.826-830
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• 2015

Transparent Ag nanowire conducting thin films with high surface hardness were fabricated by bar coating method. When coating speed was changed from 35 mm/sec to 50 mm/sec, the transmittance of coated glass increased from 65.3% to 80.8% in visible light range and the surface resistance was changed from $10.1{\Omega}/sq$ to $23.3{\Omega}/sq$. The surface hardness and adhesion of thin film were 5H and 5B.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.12
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• pp.821-825
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• 2015

Anti-reflective (AR) thin film was fabricated on a glass substrate by sol-gel method. The coating solution was synthesized with TEOS (tetraethlyorthosilicate) and poly ethylene glycol (PEG, 4.0 wt%). As the withdrawal speed of coating was changed from 0.1 mm/sec to 0.3 mm/sec, the thickness and refractive index of prepared thin films were changed. The reflectance and transmittance of coating glass fabricated by the withdrawal speed of 0.1 mm/sec were 0.62% and 95.0% in visible light range. The refractive index and thickness of single layer thin film were n= 1.29 and ca. 99.0 nm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.1
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• pp.40-43
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• 2016

Transparent color coating films were fabricated on a glass substrate by using sol-gel hybrid binder and organic dye. Sol-gel hybrid binder coating film fabricated with PTMS of 0.03 mole showed a very high pencil hardness of 9 H. As the withdrawal speed increased from 1.0 mm/s to 5.0 mm/sec, The yellowness ($b^*$) of coating glass also gradually increased. The transmittance of yellow color coating glass was 82.6% and the haze of coating glass was 0.35%. Red and blue color coating glasses also showed the high transmittance of 62.4% and 80.6% respectively. The surface hardness of color coating films was 6 H.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.464-464
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• 2007

환경오염으로 인한 각종 질병 및 증후군 등의 발생으로 가정용 산업용에서 환경관련 기술들이 다양한 분야로 확대되고 있다. 본 연구에서는 양이온 및 음이온 양쪽이온을 최대한 발생시키며, 오존 발생량은 억제하고 소비전력을 절감하고자 Ag-Pd 전극을 적용한 세라믹스 클러스터를 개발하였다. Ag-Pd 전극과 매칭되는 세라믹스 조성을 개발한 후 적층공정 기술을 이용하여 후막형 클러스터를 제조하였다. 전극 패턴모양, 전극간 방전간격 및 전극 보호층의 두께에 따른 음이온 발생량을 측정하여 최적화를 위한 실험을 진행하였으며, 음이온 발생량 100만개이상, 오존발생량 0.6ppb인 특성을 확인하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.339-339
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• 2007

Metal coating on ceramic powder has long been attracting interest for various applications such as superconductor where the brittle nature of high temperature ceramic superconductor was complemented by silver coating and metalloceramics where mechanical property improvement was achieved via electroless plating. More recently it has become of great interest in embedded passive device applications since metal coating on ceramic particles may result in the enhancement of the dielectric properties of ceramic-polymer composite capacitors. In our study, nickel ion-containing solution was used for coating commercial capacitor-grade $BaTiO_3$ powder. After filtering process, the powder was dried and heat-treated in 5% forming gas at $900^{\circ}C$. XRD and TEM were utilized for the observation of crystallization behavior and morphology of the particles. It was found that the nickel coating characteristics were strongly dependent on the several parameters and processing variables, such as starting $BaTiO_3$ particle size, nickel source, solution chemistry, coating temperature and time. In this paper, the effects of these variables on the coating characteristics will be presented in some detail.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.516-521
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• 2014

This paper describes the development of a new piezoelectric unimorph cantilever structure intended to improve electrical output power, compared to a conventional cantilever. The proposed structure employs a cylindrical bar attached to one side of a steel plate, which is a significant factor in forced vibration mode. The feasibility of the proposed methodology was assessed experimentally and theoretically. The influence of three different types of bar material (i.e., stainless steel, silicon rubber, and urethane), and bar position, on the output voltage were examined and compared with those without the bar. The optimal position and material for the bar were identified through experimental and theoretical analyses. It appears that the electrical output power of the proposed cantilever is about 40% higher than that of a conventional unimorph cantilever.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.75-75
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• 2009

In this study, in order to develop lead-free share-mode ultrasonic motor, finite element method(FEM) simulation were executed using ATILA simulator and their results were investigated. Share mode ultrasonic motor models are made up stator and two ceramic disks and it simulated according to the different ceramic disk dimensions. The results shows optimum ceramic disk dimensions and design.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.182-182
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• 2009

The effect of Re-oxidation on the PTCR properties of Sm-doped barium titanate ceramics was investigated by means of impedance spectroscopy. Electrical properties such as resistance vs. temperature, I-V curve were measured and microstructure was observed with SEM photography. Sample was fabricated with thick film process such as tape casting of green sheet, screen printing of electrode pattern, stacking, firing in reduced atmosphere and re-oxidation, etc. As the temperature of re-oxidation increases, resistance jump as a function of temperature enhances but resistance at room temperature increases. These behavior of resistance as a function of temperature, dependent on the re-oxidation condition, is analyzed with Cole-Cole impedance plot and is shown to be related with the degree of oxidation of grain boundary regardless of grain core during re-oxidation process of sample.