• 한국식품과학회지
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• 제7권4호
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• pp.212-220
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• 1975

국내에서 새로이 보급된 Indica형 장려품종인 통일미(統一米)와 Japonica형 재래장려품종인 진흥미(振興米)의 취반기호특성(炊飯嗜好特性)을 비교, 검토한 결과는 다음과 같다. 통일미는 진흥미와 비교할 때 취반시(炊飯時) 같은 가수율(加水率)에서 $4{\sim}6%$ 더 많은 수분을 흡수하였고 항상 높은 hardness를 나타내었으며 같은 hardness를 유지하기 위하여 20% 더 많은 가수율(加水率)을 요구하였다. texture특성치(特性値)중 hardness의 역수(逆數)로 부터 취반시(炊飯時) 최적가수율(最適加水率)을 구한 바 통일미는 140%, 진흥미는 120%이었다. 미반(米飯)의 호화도(糊化度)는 노화도(老化度)를 효소소화법( 酵素消化法), 요오드정색법(呈色法), texture측정법에 의하여 측정한 결과, 같은 가수율(加水率)에서 통일미는 진흥미보다 항상 낮은 호화도(糊化度)를 나타낸 반면 노화도(老化度)는 약간 떨어지는 경향이 있었다. 미분(米粉)의 amylogram 특성(特性)을 보면 통일미는 진흥미에 비하여 호화개시온도(糊化開始溫度)는 높은 반면 최고 점도(粘度)와 breakdown은 낮은 값을 나타내었다.

• 전기전자학회논문지
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• 제25권2호
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• pp.344-349
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• 2021

Super Junction구조는 항복전압과 온-상태 전압강하의 트레이드-오프 특성을 개선하고자 제안된 구조이다. 본 논문은 Super Junction IGBT P-Pillar 내부 영역에 Trench SiO₂를 성장시킨 구조를 제안한다. Super Junction구조에 인가되는 전계를 3D로 관찰 시 P-Pillar 내부에 전계가 인가되지 않는 영역을 확인하였다. Pillar영역의 부분저항은 각 Pillar의 크기와 항복전압에 의해 변동되는데 전계가 인가되지 않는 P-Pillar 내부 영역을 Trench 한 후 SiO₂를 성장시켜 P-Pillar의 크기를 감소시킨다. 4.5kV의 동일한 항복전압을 가질 때 온-상태 전압강하 특성이 Field Stop IGBT 대비 약 58%, 기존의 Super Junction IGBT 대비 19% 향상되는 것을 확인하였다.

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.119-132
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• 2024

Dielectric ceramic capacitors present high output power density due to the fast energy charge and discharge nature of dielectric polarization. By forming dense ceramic films with nano-grains through the Aerosol Deposition (AD) process, dielectric ceramic capacitors can have high dielectric breakdown strength, high energy storage density, and leading to high power density. Dielectric capacitors fabricated by AD process are expected to meet the increasing demand in applications that require not only high energy density but also high power output in a short time. This article reviews the recent progress on the dielectric ceramic capacitors with improved energy storage properties through AD process, including energy storage capacitors based on both leadbased and lead-free dielectric ceramics.

• 대한기계학회논문집B
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• 제23권2호
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• pp.288-298
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• 1999

In spark ignited engines, the electrical spark not only sets the time for the onset of combustion but also is able to greatly influence the character of the initial flame growth and the subsequent combustion, and thereby can influence engine performance. The relative importance of the ignition energy is particularly high under lean or high residual gas or exhaust gas recirculation (EGR). In this study, a modeling of flame Initiation and its development is proposed. Submodels consist in representing of cylinder pressure and temperature, heat transfer to cylinder wall, and flame kernel heat transfer to ambient air and to spark plug electrodes. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy, and laminar and turbulent flame velocity.

• Smart Structures and Systems
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• 제19권4호
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• pp.403-413
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• 2017

The present article encompasses a nonlinear finite element (FE) and genetic algorithm (GA) based optimal vibration energy harvesting from nonprismatic piezo-laminated cantilever beams. Three cases of cross section profiles (such as linear, parabolic and cubic) are modelled to analyse the geometric nonlinear effects on the output responses such as displacement, voltage, and power. The simultaneous effects of taper ratios (such as breadth and height taper) on the output power are also studied. The FE based nonlinear dynamic equation of motion has been solved by an implicit integration method (i.e., Newmark method in conjunction with the Newton-Raphson method). Besides this, a real coded GA based constrained optimization scheme has also been proposed to determine the best set of design variables for optimal harvesting of power within the safe limits of beam stress and PZT breakdown voltage.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.450-456
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• 2005

In this paper, the effect of adhesion properties of semiconductive-insulating interface layer of silicone rubber on electrical properties was investigated. The modifications produced on the silicone surface by oxygen plasma were accessed using ATR-FTIR, contact angle and Surface Roughness Tester. Adhesion was obtained from T-peel tests of semiconductive layer haying different treatment durations. In addition, ac breakdown test was carried out for elucidating the change of electrical property with duration of plasma treatment. From the results, the treatment in the oxygen plasma produced a noticeable increase in surface energy, which can be mainly ascribed to the creation of O-H and C=O. It is observed that adhesion performance was determined by surface energy and roughness level of silicone surface. It is found that at dielectric strength was increased with improving the adhesion between the semiconductive and insulating interface.

• 전기학회논문지
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• 제60권5호
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• pp.955-964
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• 2011

In renewable energy system such as flywheel energy storage system, wind power and solar power, the motor/generator is the important key for offering the electric energy to the electric loads. For example, the heavy and large flywheel is rotated by electromagnetic torque of pemanent magnet synchronous motor (PMSM) and, in case of a breakdown of electric current, the PMSM used as generator supplies electric energy for the various electric utilities using mechanical rotation energy of the flywheel. Thus, design of a motor/generator should be performed in effort to reduce cogging torque and electromagnetic loss for high efficiency. In our paper, a slotless permanent magnet synchronous motor/generator (SPMSM/G) with output power 15kW at the rotor speed 18000rpm is designed from electromagnetic analysis and dynamic performance analysis. In analytical approach, design parameters such as back electro-motive force (back EMF), inductance and electromagnetic torque are derived from analytical method which is one of the electromagnetic analysis method. And using the design parameters, this paper deal with system design considering the driving characteristics and electric load in required power. Finally, the analytical results are verified by the experiment and finite element method (FEM).

• 한국초전도ㆍ저온공학회논문지
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• 제19권3호
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• pp.49-53
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• 2017

The superconducting magnets have a large inductance as well as high operating current. Therefore, mega-joule scale energy can be stored in the magnet. The energy stored in the magnet is sufficient to damage the magnet when a quench occurs. Quench heater and dump resistor can be used to protect the magnet. However, using quench heater to create quench resistors through heat transfer can be slower than instantly switching resistors. Also, electrical short, overheating and breakdown can occur due to quench heater. Moreover, the number of dump resistor should be limited to avoid large terminal voltage. Therefore, in this paper, we propose a quench protection method for extracting the energy stored in a magnet by charging and discharging energy through a capacitor switching without increasing resistance. The simulation results show that the proposed system has a faster current decay within the allowable voltage level.

• 생물환경조절학회지
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• 제29권3호
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• pp.306-312
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• 2020

본 연구에서는 여름철 고온기 시설재배시 수시차광이 내부환경과 오이 생리적 반응에 미치는 영향을 검토하였다. 온실차광이 오이의 고온 스트레스 완화 정도를 추정하기 위하여 잎 온도, 엽기온차, 최대 카르복실화속도, 최대 전자전달 속도, 열파괴, 광호흡과 같은 오이의 생리적 반응을 측정 분석하였다. 오이 시설하우스의 차광율은 90% 수시차광, 40% 수시차광, 무차광 3수준의 실험 조건으로 하였다. 90% 수시차광은 외부 일사량이 650 W·m^-2일 때 차광되도록 하였다. 기온, 일사량, 엽온, 엽기온차, 광호흡은 90%의 수시차광에서 40% 수시차광과 무차광 처리 보다 낮은 값을 나타내었다. 최대 카르복실화속도, 광호흡율은 90% 수시차광 온실이 다른 처리구보다 유의하게 낮은 것으로 나타났다. 고온저항성을 나타내는 thermal breakdown 값은 90%의 수시차광에서 다른 처리구 보다 유의하게 높은 것으로 나타났다. 따라서, 90% 수시차광이 여름철 오이 재배에 있어 고온스트레스를 덜받는 생육환경을 조성하였다는 결과를 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2071-2072
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• 2011

Withstand voltage characteristics of the nanocomposites, as a material with excellent abrasion resistance and water resistance, low shrinkage upon curing with moisture even in very good adhesion, workability is not lost. In this study, the fusion of nanoparticles and the high functionality epoxy nano-composite material produces the electricity. Degeneration of the unit based on this power structure and breakdown characteristics, efficiency and cross-measurement system as closely related organisms that can be applied to the power plant electrical efficiency of the nano-composite material is designed to develop skills.