• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 춘계학술대회
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• pp.247-257
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• 2004

Electrodes were fabricated based on activated carbon powder BP-20, conducting agent such as Super P, vapor grown carbon fiber (VGCF) and acetylene black (AB), and the mixed binders of flexible poly(vinylidenefluoridehexafluoropropylene) [P(VdF-co-HFP)] and cross linking dispersion agent of polyvinylpyrrolidone (PVP) to increase mechanical strength. According to impedance measurement of the electrode with the addition of conducting agent, we found that it was possible to charge rapidly by the fast steady-state current convergence due to low equivalent series resistance (AC-ESR, fast charge transfer rate at interface between electrode and electrolyte and low RC time constant. The self-discharge of unit cell showed that diffusion process was controlled by the ion concentration difference of initial electrolyte due to the characteristics of Electric Double Layer Capacitor (EDLC) charged by ion adsorption in the beginning, but this by current leakage through the double-layer at the electrode/electrolyte interface had a minor effect and voltages of curves were remained constant regardless of electrode material. We found that the 2.3V/230F grade EDLC would be applied to industrial safety usage such as uninterrupted power supply (UPS) because of the constant DC-ESR by IR drop regardless of discharge current.

• Interaction and multiscale mechanics
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• 제1권2호
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• pp.251-278
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• 2008

In this study, we investigate the discontinuous-derivative treatment at the gas-liquid interface in underwater explosion (UNDEX) problems by using the Moving Least Squares-Smoothed Particle Hydrodynamics (MLS-SPH) method, which is known as one of the particle methods suitable for problems where large deformation and inhomogeneity occur in the whole domain. Because the numerical oscillation of pressure arises from derivative discontinuity in the UNDEX analysis using the standard SPH method, the MLS shape function with Discontinuous-derivative Basis Function (DBF) that is able to represent the derivative discontinuity of field function is utilized in the MLS-SPH formulation in order to suppress the nonphysical pressure oscillation. The effectiveness of the MLS-SPH with DBF is demonstrated in comparison with the standard SPH and conventional MLS-SPH though a shock tube problem and benchmark standard problems of UNDEX of a trinitrotoluene (TNT) charge.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.411-414
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• 1999

70 ${\AA}$-thick oxides nitridied at various conditions were reoxidized at pemperatures of 900$^{\circ}C$ in dry-O$_2$ ambients for 5～40 mininutes. The gate oxide interface porperties as well as the oxide substrate interface properties of MOS(Metal Oxide Semiconductor) capacitors with various nitridation conditions, reoxidation conditions and pure oxidation condition were investigated. We stuided I$\sub$g/-V$\sub$g/ characteristics, $\Delta$V$\sub$g/ shift under constant current stress from electrical characteristics point of view and breakdown voltage from leakage current point of view of MOS capacitors with SiO$_2$, NO, RNO dielectrics. Overall, our experimental results show that reoxidized nitrided oxides show inproved charge trapping porperites, I$\sub$g/-V$\sub$g/ characteristics and gate $\Delta$V$\sub$g/ shift. It has also been shown that reoxidized nitridied oxide's leakage currented voltage is better than pure oxide's or nitrided oxide's from leakage current(1${\mu}$A) point of view.

• 전자공학회논문지A
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• 제30A권2호
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• pp.53-63
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• 1993

Device degradations by the Fowler-Nordheim tunneling have been studide. The changes of device characteristics such as the threshold voltage, subthreshold slope, I-.or. curves have been measured after bidirectionally stressing n-channel MOSFET's and p-channel MOSFET's. Also the interface states have been directly measured by the charge pumping methodIt is shown that the change of interface states is determined by the number of hole carriers tunneling the gate oxide and electrons which are trapped in the gate oxide. Also, in this paper, we propose a model for device lifetime limited by the increase of interface states.

• 한국세라믹학회지
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• 제52권5호
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• pp.356-360
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• 2015

The specific role of current collectors was investigated at the electrolyte/electrode interface of solid oxide fuel cells (SOFCs). Ag grids were fabricated as current collectors using electrohydrodynamic (EHD) jet printing for precise control of the grid geometry. The Ag grids reduced both the ohmic and polarization resistances as the pitch of the Ag grids decreased from $400{\mu}m$ to $100{\mu}m$. The effective electron distribution along the Ag grids improved the charge transport and transfer at the interface, extending the active reaction sites. Our results demonstrate the applicability of EHD jet printing to the fabrication of efficient current collectors for performance enhancement of SOFCs.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.903-906
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• 2009

본 연구에서는 임베디드 시스템, 특히 블루투스 베이스밴드에서 사용이 가능한 고속 직렬 포트 인터페이스를 설계하였다. 인터페이스는 ARM 프로세서를 응용할 수 있는 AMBA APB에 호환될 수 있도록 설계하였으며, 8비트 형태로 외부 디바이스와 코프로세서 간 데이터와 명령을 전송할 수 있다. 오류 정정을 위하여, CRC를 적용하였고 멀티미디어 카드를 위한 인터페이스도 제공하였다. 설계한 직렬 포트 인터페이스는 자동합성하여 P&R을 수행하였다. 결과물은 Altera FPGA로 구현하였으며 25MHz에서 정상동작하였다.

• 한국전기전자재료학회논문지
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• 제15권12호
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• pp.1079-1084
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• 2002

Because complex insulation method is used in EHV(extra high voltage) insulation systems, macro Interfaces between two different bulk materials which affect the stability of insulation system exist inevitably. Interface between toughened epoxy and silicone rubber was selected as a interface in EHV insulation systems and tested AC interfacial breakdown properties with variation of many conditions to influence on electrical Properties, such as interfacial pressure, roughness and oil. Specimen was designed to reduce the effect of charge transport from electrode in the process of breakdown and to have the tangential electrical potential with the direction of the interface between epoxy and silicone rubber by using FEM(finite elements method). It could control the interfacial pressure, roughness and viscosity of oil. From the result of this study, it was shown that the interfacial breakdown voltage is improved by increasing interfacial Pressure and oil. In particular, the dielectric strength saturates at certain interracial Pressure level. The decreasing ratio of the interfacial breakdown voltage in non-oiled specimen was increased by the temperature rising, while oiled specimen was not affected by temperature.

• Transactions on Electrical and Electronic Materials
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• 제1권4호
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• pp.25-29
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• 2000

In this paper, PET(Ployethylene Terephthalate) films with semiconducting and interface layers were investigated, The electrical properties, such as volume resistivity, tan$\delta$(dissipation factor) and breakdown strength at various temperatures were measured. Thermal analysis of PET and semiconducting films were measured and compared by differential scanning calorimeter(DSC) of each film. It is found that the volume resistivity of films(dependence on semiconducting interface layers)and electrical properties of PET films are changed ,Breakdown strength and dissipation factor of PET films with semiconducting layer (PET/S/PET) are decreased more greatly than PET and PET/PET films, due to the increase of charge density of charges at two contacted interfaces between PET and semiconductor, The dissipation factor of each films in increased with temperature,. For PET/S/PET film, is depended on temperature more than PET of PET/PET. However, the breakdown strength is increased up to 85$\^{C}$ and then decreased over 100$\^{C}$The electrical properties of PET films with semiconducting/interface layer are worse than without it It is due to a result of temperature dependency, which deeply affects thermal resistance property of PET film more than semiconducting/interface layers.

• 센서학회지
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• 제31권4호
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• pp.271-277
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• 2022

We analyzed the effects of the interface trap on the output characteristics of an inversion mode n-channel GaN Schottky barrier (SB)-MOSFET based on the N_it distribution using TCAD simulation. As interface trap number density (N_it) increased, the threshold voltage increased while the drain current density decreased. Under N_it=5.0×10¹⁰ cm^-2 condition, the threshold voltage was 3.2 V for V_DS=1 V, and the drain current density reduced to 2.4 mA/mm relative to the non-trap condition. Regardless of the N_it distribution type, there was an increase in the subthreshold swing (SS) following an increase in N_it. Under U-shaped N_it distribution, it was confirmed that the SS varied depending on the gate voltage. The interface fixed charge (Q_f) caused an shift in the threshold voltage and increased the off-state current collectively with the surface trap. In summary, GaN SB-MOSFET can be a building block for high power UV optoelectronic circuit provided the surface state is significantly reduced.

• 전기전자학회논문지
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• 제18권4호
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• pp.620-624
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• 2014

본 연구에서는, Ni/CNT/$SiO_2$ 구조의 4H-SiC MIS 캐패시터를 제작하고 전기적 특성을 조사하였다. 이를 통하여 4H-SiC MIS 소자에서 탄소나노튜브의 역할을 분석하고자 하였다. 탄소나노튜브는 이소프로필알코올과 혼합하여 $SiO_2$ 표면에 분산하였다. 소자의 전기적 특성 분석을 위하여 300-500K의 온도 범위에서 소자의 정전용량-전압 특성을 측정하였다. 밴드 평탄화 전압은 양의 방향으로 shift되었다. 정전용량-전압 그래프로부터 계면 포획 전하 밀도 및 산화막 포획 전하 밀도가 유도되었다. 산화막의 상태는 4H-SiC MIS 구조의 계면에서 전하 반송자 또는 결함 상태와 관련된다. 온도가 증가함에 따라 밴드 평탄화 전압은 음의 방향으로 shift되는 결과를 얻었다. 실험 결과로부터, Ni과 $SiO_2$ 계면에 탄소나노튜브를 첨가함에 따라 4H-SiC MIS 캐패시터의 게이트 특성을 조절 가능할 것으로 판단된다.