• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.784-789
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• 2004

Bulk ZnO varistor based on Matsuoka, which varied $SiO_2$ addition has fabricated by standard ceramic process. The micro-electrode, which fabricated for investigation on degradation property of the Single Grain Boundary of ZnO varistor, has sticked by lithography semiconductor process. The values of AC degradation has measured with 150% operating voltage in varistor threshold with 120 minute in 60Hz. In here we observed V-I and V-C property in every 30minute. The operating voltage of Single Grain Boundary has shown in variable patterns in the characteristic of V-I Property. By increasing the $SiO_2$ contents, operating value has also increased and dominated on degradation proper. In EPMA analysis, we know that added $SiO_2$ was nearly distributed at the Grain Boundary. $SiO_2$ has gradually distributed in Grain Boundary condition during the process of crystal growth. It contributes to degradation depression and decision of operating voltage. We also demonstrated for using practical application and performance on distribution random loop based on V-I Properties in Single-Grain-Boundary.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.417-418
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• 2008

Transparent conductive oxide (TCO) are necessary as front electrode or anti-reflecting coating for increasing efficiency of LED and Photodiode. In this paper, aluminum-doped Zinc oxide films(AZO) were prepared by DC magnetron sputtering on glass(corning 1737) and Si substrate at temperature of $100^{\circ}C$ and then annealed at temperature of $400^{\circ}C$ for 1hr in Ar and vaccum. The AZO films were etched in diluted HCL (0.5 %) to examine the surface morphology properties. After annealing, Structural and electrical property were investigated. The c-axis orientation along (002) plane was enhanced and the electrical resistivity of the AZO film decreased from $1.1\times10^{-1}$ to $1.6\times10^{-2}{\Omega}cm$. We observed textured structure of AZO thin film etched for 2s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.208-211
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• 2003

In this paper, mechanical property of electric epoxy with water aging was discussed. We studied mechanical property of elastic resin after absorption in water from 0 to 484 hour. As a result, diffusion factor of elastic epoxy showed $20-21{\times}10^{-4}mm^2/s$ and general epoxy showed $9.5{\times}10^{-4}mm^2/s$. Elastic property increased linearly according to amount of addictives and decreased elastic property according to amount of water absorption. Tensile strength was reduced to add to addictives. It was effected by water absorption of micro-void of elastic epoxy. Hardness inclined to decrease after increasing according to absorbed time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.319-322
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• 2004

In this paper, we studied on the thermal conductivity and a mechanical property of the elastic epoxy. According to industrial development, insulation materials have various properties. They are solid, liquid, gas state, there are various type. Epoxy, a kind of insulation material, demand of not only high hardness but also elastic property. When the electric current flows into the conductor and the place where the heat occurs, this heat becomes the cause which shortens the life of the electrical appliance. Therefore, for the heat occurred transmit quickly, thermal conductivity of the insulation material is highly demanded. We studied on the thermal conductivity of elastic epoxy on the high voltage. In this result, thermal conductivity confirmed that it followed thermal property of mixed epoxy and addictives. Hardness is decreased when addictives increased.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.942-944
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• 2004

This paper proposes a delta-operator-based digital redesign (DR) technique. An asymptotic property of the delta-operator-based DR is analyzed. The performance recovery is proved as a sampling time approaches zero.

• Electrical & Electronic Materials
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• v.8 no.3
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• pp.372-381
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• 1995

본 논문에서는 분체 특성 평가 연구의 국제 동향과 입자형태, 입도분포, 비표면적, 분체밀도, 기공도, 화학분석 평가분야의 기본원리, 특히 측정시 변수들의 영향과 이러한 특성변화에 따른 전기적성질 변화에 대하여 간단히 언급을 하였다. 분체 특성평가분야의 연구는 선진국에 비해 낙후되어 있고 관심도 또한 낮은 형편이다. 이 분야의 학문적, 산업적인 중요점을 고려할 때, 분체 특성 평가에 대한 기초 및 응용연구가 활성화되었으면 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.402-405
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• 2012

In this paper, we proposed a novel metamaterial unit cell utilizing an interdigital capacitor(IDC) with non-bianisotropic property. Due to the induced magnetic resonance of an IDC unit cell, exotic effective constitutive parameters can be realized like a split ring resonator(SRR). Furthermore, the proposed unit cell is electrically smaller than a conventional SRR unit cell. The effective parameters retrieved from the transmission responses of waveguide measurement method and simulated results show good agreement.

• Transactions on Electrical and Electronic Materials
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• v.14 no.1
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• pp.36-38
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• 2013

Eight sample panels using an indium tin oxide(ITO)-coated glass substrate were fabricated, with barrier ribs formed of 55 ${\mu}m$ height and 10 ${\mu}m$ width. The upper and lower substrates were designed with the same panel condition, so a cell gap of 110 ${\mu}m$ was obtained. The charged particles in a cell consisted of $TiO_2$ (for white color) or carbon black (black color), negative or positive charge control agents, and a polymer. The average diameter of the two types of particles was commonly 10 ${\mu}m$, and their q/m value was -4.5 ${\mu}C/g$ and +4.5 ${\mu}C/g$, respectively. The electrically opposite particles mixed by an agitator were loaded into their cells by a simple particle-loading method. The discharging process proceeded at a humidity of 80% and a temperature of $30^{\circ}C$. Reflectivity was measured depending on discharging time, and a hysteresis curve by bias voltage obtained for comparison between the neutralized and non-neutralized panel, in which the superior optical property of the neutralized panel was ascertained.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.36-43
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• 2016

Visualization of the tissue loss tangent property can provide distinct contrast and offer new information related to tissue electrical properties. A method for non-invasive imaging of the electrical loss tangent of tissue using magnetic resonance imaging (MRI) was demonstrated, and the effect of loss tangent was observed through simulations assuming a hyperthermia procedure. For measurement of tissue loss tangent, radiofrequency field maps ($B_1{^+}$ complex map) were acquired using a double-angle actual flip angle imaging MRI sequence. The conductivity and permittivity were estimated from the complex valued $B_1{^+}$ map using Helmholtz equations. Phantom and ex-vivo experiments were then performed. Electromagnetic simulations of hyperthermia were carried out for observation of temperature elevation with respect to loss tangent. Non-invasive imaging of tissue loss tangent via complex valued $B_1{^+}$ mapping using MRI was successfully conducted. Simulation results indicated that loss tangent is a dominant factor in temperature elevation in the high frequency range during hyperthermia. Knowledge of the tissue loss tangent value can be a useful marker for thermotherapy applications.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.250-253
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• 2015

High contrast grating (HCG) is the structure made up of the sub-wavelength grating of high-index and the surrounding layer of low-index, which reveals high contrast between two materials. Its advantages include high reflectivity over a broad bandwidth, polarization and wavelength selectivity, optical high-Q resonator, and phase modulation. In this work, the HCG structure comprising of indium tin oxide (ITO) and Silicon (Si), for the surrounding layer and the grating layer respectively, was studied. Its theoretical model was established, and transmittance, phase and optical behavior were calculated by rigorous coupled-wave analysis and finite element method. Furthermore, the established structure was fabricated to validate its feasibility. The fabricated structure shows the focusing capability whose length is about $10{\mu}m$, and the feasibility of the structure was demonstrated. It is also meaningful that ITO layer can contribute to the fabrication of the HCG structure, leading to enable the structure to be electrical-driven.