• 제목/요약/키워드: 이중에너지

검색결과 996건 처리시간 0.034초

이중분사식 수소기관의 비정상 열부하 해석에 관한 연구 (A Study on Unsteady Thermal Loading of Hydrogen Engine with Dual Injection)

  • 위신환;김윤영;김홍준;이종태
    • 한국수소및신에너지학회논문집
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    • 제12권2호
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    • pp.147-155
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    • 2001
  • To measure of thermal loading in the combustion chamber of hydrogen engine with dual injection, instantaneous wall-surface temperature and unsteady heat flux of the cylinder head are measured and analyzed. The maximum wall surface temperature is shown in direct injection region which has large heat supplied. Partial and spatial temperatures have slight deviation in transient region of injection, though injection method change suddenly. All of thermal characteristics such as instantaneous temperature, temperature swing and heat flux of hydrogen engine with dual injection are remarkably higher than those of gasoline engine. It means necessity of additional countermeasure of thermal loading.

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열성능을 고려한 다층형 이중외피의 중공층 높이에 관한 연구 (A Study on the Cavity Height of Muti-Story Double-Skin Facade for better Thermal Performance)

  • 신선준;조재훈;석호태;김광우
    • 한국태양에너지학회 논문집
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    • 제25권2호
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    • pp.53-62
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    • 2005
  • In this study, the thermal performance of multi-story double-skin facade(DSF) with variation of cavity height is evaluated to offer useful data in determining cavity height of multi-story DSF. For this, thermal criteria for multi-story DSF is adopted and a DSF model for evaluation of the thermal performance is established. Through the evaluation of CFD simulation, the recommended height of multi-story DSF is 5 stories or less to improve the thermal performance during the intermediate season.

이중 팽창을 채용한 유기 플래시 사이클(OFC)의 열역학적 성능 특성 (Characteristics of Thermodynamic Performance of Organic Flash Cycle (OFC) with Double Expansion)

  • 김경훈;한철호;정영관
    • 한국수소및신에너지학회논문집
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    • 제29권5호
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    • pp.483-489
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    • 2018
  • Recently proposed organic flash cycle (OFC) was shown to potentially improve power generation using low grade heat source. In this paper, a thermodynamic performance is carried out for a modified OFC employed double expansions. Effects of the selection of working fluid and the important system parameters such as the temperatures in flash evaporators on the system performance were extensively investigated. Results showed that the system performances are strongly influenced with the system parameters and selection of the working fluid, and the power generation can be increased compared to the basic OFC.

이중구조 촉매층으로 구성된 MEA의 성능 평가 (Performance Evaluation on MEA with Double Layered Catalyst)

  • 김홍건;곽이구;강성수;강영우
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.55-58
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    • 2006
  • An experimental study is performed to evaluate the performance and the efficiency by humidifying MEA and by making the double-layered catalyst in a fuel cell system which is taken into account the physical and thermal concept. An electrical output produced by PEMFC(Polymer Exchange Membrane Fuel Cell) is measured to assess the performance of the stack and the efficiency is also evaluated according to the different situation in which is placed with and without the humidification of MEA(Membrane Electrolyte Assembly). Subsequently, It is found that the measured values of MEA voltage and current are influenced by the MEA temperature, humidification, and the double-layered catalyst which gives more enhanced values to apply for electric units.

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이중여자 유도형 풍력 발전기의 PSCAD 시뮬레이션 모델 개발 (Development of PSCAD Simulation Model for Doubly-fed Induction-type Wind Power Generation System)

  • 정병창;김희중;정용호;전영수;곽노홍;송승호
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.261-264
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    • 2006
  • In this paper, doubly-fed induction-type wind power generation system simulation model for grid connection is developed. The simulation model is based on PSCAD/EMTDC and consists of rotor-blade, blade controller, generator power converter and generator controller Blade controller controls the blade pitch angle for starting, peak power limiting and emergency condition. Generator controller controls the generator output power to maximize the system efficiency. Simulation results are shown for the variable wind speed conditions. The simulation model can be utilized for study of actual interaction between wind turbine and grid for reliable operation and protection of power system.

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Sparse 표현을 이용한 이중 에너지 X 선 흡수 영상 잡음 제거 (Noise Reduction for Dual-energy X-ray Absorptiometry Image using Sparse Representation)

  • 김형일;엄원용;김대회;노용만
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2012년도 춘계학술발표대회
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    • pp.369-372
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    • 2012
  • 대사성 골 질환인 골다공증(Osteoporosis)의 조기 진단을 위한 골 밀도를 측정하는 방법이 최근 연구되고 있다. 골 밀도 영상은 이중 에너지 X 선 흡수법에 의해 측정되는데, 영상에 존재하는 잡음은 뼈 영역 추출과 골 밀도 계산에 어려움을 주고 있다. 따라서 본 논문에서는 최근 신호처리 분야에서 폭넓게 사용되고 있는 sparse 표현을 도입하여 X 선 영상의 잡음을 제거하는 방법을 제안한다. 실험을 통해 제안한 잡음 제거 방법의 결과가 기존의 방법에 비해 개선됨을 MSR(Mean to Standard deviation Ratio)과 CNR(Contrast to Noise Ratio)을 통해 확인하였다.

450mm 웨이퍼 공정을 위한 이중 주파수 유도결합 플라즈마 소스의 개발 및 특성 연구

  • 강승현;김태형;;정호범;배정운;염근영
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2012년도 춘계학술발표회 논문집
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    • pp.334-334
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    • 2012
  • 다음 세대 웨이퍼 공정인 450mm 웨이퍼 공정을 위한 이중 주파수 유도결합 플라즈마 소스를 이용하여 각각의 안테나에 파워를 인가하고, 이 때 방전되는 플라즈마의 특성을 Langmuir probe를 통하여 확인할 수 있었다. 또한 인가되는 파워를 조절하여 플라즈마 내의 전자에너지를 조절할 수 있다는 가능성을 확인할 수 있었다.

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