• Journal of Advanced Marine Engineering and Technology
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• 제30권6호
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• pp.702-708
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• 2006

This study shows the experimental characteristics of the double pipe inserted liquid pipe with small diameter in the gas pipe with large diameter for circulating of a liquid of high temperature, pressure and a gas of low temperature, pressure at the same time. So the functions of pipe and pipe's expansion and heat transfer are presented simultaneously. In the result, the temperature of gas refrigerant at the inlet of compressor increased about $5^{\circ}C$ by the heat transfer with liquid refrigerant in case of the double pipe. And liquid gas refrigerant which the temperature at the inlet of evaporator decreased about $3^{\circ}C$ comparing with the existing type flows into an evaporator COP of the double pipe increased about $7{\sim}10%$ comparing with that of the conventional pipe. And the noise of the double pipe at capillary tube is less than that of the conventional type about 3dB. Consequently. it is convinced the superiority of the double pipe in the heat loss and soundproofing aspect.

• 한국음향학회지
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• 제16권6호
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• pp.54-60
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• 1997

본 논문에서는 SC 적분기와 SC Lossy 적분기로 구성된 SC필터에서 위상에러를 제거하기 위한 LDI 클럭방법 및 SC Lossy 적분기의 댐핑항에서 허수부분을 제거할 수 있는 방법을 제시하여 LDI 5차 elliptic 저역통과 SC 필터를 설계하였다. SC 필터 CMOS OP=AMP를 전원전압 ${\pm}$5V, MOSIS 2-${\mu}$m double-poly double-metal n-well CMOS 공정파라미터로 설계하여 SC 시뮬레이터인 SCANAP 프로그램을 통해 시뮬레이션 한 결과 설계된 SC 필터특성이 개선되었다. 집적회로를 위하여 MOSIS 2--${\mu}$m double-poly double-metal n-well CMOS 설계규칙에 따라 레이아웃 하였다.

• 전기전자학회논문지
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• 제25권1호
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• pp.15-24
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• 2021

본 논문에서는 CDT(Conventional Double Trench) MOSFET보다 스위칭 시간과 손실이 적은 1700 V EPDT(Extended P+ shielding floating gate Double Trench) MOSFET 구조를 제안하였다. 제안한 EPDT MOSFET 구조는 CDT MOSFET에서 소스 Trench의 P+ shielding 영역을 늘리고 게이트를 N+와 플로팅 P- 폴리실리콘 게이트로 나누었다. Sentaurus TCAD 시뮬레이션을 통해 두 구조를 비교한 결과 온 저항은 거의 차이가 없었으나 Crss(게이트-드레인 간 커패시턴스)는 게이트에 0 V 인가 시에는 CDT MOSFET 대비 32.54 % 줄었고 7 V 인가 시에는 65.5 % 감소하였다. 결과적으로 스위칭 시간 및 손실은 각각 45 %, 32.6 % 줄어 스위칭 특성이 크게 개선되었다.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2628-2633
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• 2009

초소형 전자 칼럼에서 이중 편향기는 칼럼의 왜곡 수차의 최소화 및 FOV(field of view)의 극대화 효과를 위하여 사용하고 있다. 이러한 효과를 관찰하기 위하여 이중 편향기에 서로 반대로 전압을 인가한 상태에서 FOV와 주사 폭의 변화에 대한 실험을 진행하였으며, 최대 FOV와 주사 폭에 대한 적정 조건을 얻기 위한 각 편향기의 인가 전압과 전자 방출 팁 전압의 관계를 조사하였다. 또한 전자 방출 팁 전압에 의한 줌 기능의 선형성과 줌 한계를 측정하여 분석하였다.

• 한국입자에어로졸학회지
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• 제10권3호
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• pp.99-108
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• 2014

Liquid filtration by membrane filters is essential for the preparation of ultrapure water in semiconductor manufacturing processes. The separation of submicrometer particles suspended in ultrapure water with a laminated fibrous membrane filter was studied numerically and experimentally in the present work. We found that an electrical double layer around a single fiber expanded to a large extent at a low ion concentration, as in ultrapure water, and deformed toward the upstream of the fiber with increasing filtration velocity. Since an increase in the electrical double-layer thickness leads to a decrease in the electrical potential gradient, particles with the same polarity as the fiber approach the fiber more easily and are captured at a high filtration velocity. Experimental results also confirmed that the collection efficiency of polystyrene latex(PSL) particles through a PTFE filter became higher as the filtration velocity increased.

• Journal of Power Electronics
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• 제10권1호
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• pp.72-78
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• 2010

In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Formulae describing the factors affecting the range of sub-synchronous speeds within which generation occurs are deduced. The variations in the magnitude and phase angle of the voltage injected to the rotor circuit as the speed of the machine changes to achieve generation at the widest possible sub-synchronous speed range is presented. Also, the effect of the rotor parameters on the generation range is presented. The analysis proved that the generation range could increase from sub-synchronous to super-synchronous speeds, which increases the amount of energy captured by the wind energy conversion system (WECS) as result of utilizing the power available in the wind at low wind speeds.

• 한국전기전자재료학회논문지
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• 제24권1호
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• pp.70-75
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• 2011

We introduced nanoscale interfacial layers between the PV layer and the cathode in poly (3-hexylthiophene):methanofullerene bulk-heterojunction polymer photovoltaic (PV) cells. The nanoscale double interfacial layers were made of ultrathin poly (oxyethylenetridecylether) surfactant and low-work-function alloy-metal of Al:Li layers. It was found that the nanoscale interfacial layers increase the photovoltaic performance, i.e., increasing short-circuit current density and fill factor with improved device stability. For PV cells with the nanoscale double interfacial layers, an increase in power conversion efficiency of $4.18{\pm}0.24%$ was achieved, compared to that of the control devices ($3.89{\pm}0.08%$) without the double interfacial layers.

• 신재생에너지
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• 제10권4호
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• pp.3-8
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• 2014

Both of induction generator and synchronous generator is available in the hydroelectric power plant. If the output of the power station is large, the synchronous generator is mainly used but when its output is low, the induction generator is often used. If the output capacity is small, there is a case in which induction motor is used as a generator. Torque at rated operation and start of the induction motor is different depending on the shape of the rotor. Small and medium-sized squirrel-cage induction motor is used primarily double cage rotor or deep bar. In this study, we attempt to interpret characteristics for double cage rotor or deep bar that occur when operating in the induction generator based on the parameters that have been designed and manufactured as an induction motor.

• Structural Engineering and Mechanics
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• 제27권4호
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• pp.501-521
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• 2007

This study presents a model to better understand the shear behavior of reinforced concrete walls subjected to lateral load. The scope of the study is limited to squat walls with height to length ratios not exceeding two, deformed in a double-curvature shape. This study is based on limited knowledge of the shear behavior of low-rise shear walls subjected to double-curvature bending. In this study, the wall ultimate strength is defined as the smaller of flexural and shear strengths. The flexural strength is calculated using a strength-of-material analysis, and the shear strength is predicted according to the softened strut-and-tie model. The corresponding lateral deflection of the walls is estimated by superposition of its flexibility sources of bending, shear and slip. The calculated results of the proposed procedure correlate reasonably well with previously reported experimental results.

• ETRI Journal
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• 제34권2호
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• pp.256-259
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• 2012

The double-base number system has been used in digital signal processing systems for over a decade because of its fast inner product operation and low hardware complexity. This letter proposes an innovative multiplier architecture using hybrid operands. The multiplier can easily be linked to flash analog-to-digital converters or digital systems through a double-base number encoder (DBNE) for realtime signal processing. The design of the DBNE and the multiplier enable faster digital signal processing and require less hardware resources compared to the binary processing method.