• 제목/요약/키워드: High Energy

검색결과 20,377건 처리시간 0.052초

The Synthesis and Electrochemical Performance of Microspherical Porous LiFePO4/C with High Tap Density

  • Cho, Min-Young;Park, Sun-Min;Kim, Kwang-Bum;Lee, Jae-Won;Roh, Kwang Chul
    • Journal of Electrochemical Science and Technology
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    • 제3권3호
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    • pp.135-142
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    • 2012
  • Over the past few years, $LiFePO_4$ has been actively studied as a cathode material for lithium-ion batteries because of its advantageous properties such as high theoretical capacity, good cycle life, and high thermal stability. However, it does not have a very good power capability owing to the low lithium-ion diffusivity and poor electronic conductivity. Reduction in particle size of $LiFePO_4$ to the scale of nanometers has been found to dramatically enhance the above properties, according to many earlier reports. However, because of the intrinsically low tap density of nanomaterials, it is difficult to commercialize this method. Many studies are being carried out to improve the volumetric energy density of this material and many methods have been reported so far. This paper provides a brief summary of the synthesis methods and electrochemical performances of micro-spherical $LiFePO_4$ having high volumetric energy density.

고공 풍력발전 기술개발 현황 (Technology Development Trends for High Altitude Wind Power Genration)

  • 김석우;김현구
    • 한국태양에너지학회 논문집
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    • 제30권1호
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    • pp.19-24
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    • 2010
  • At the altitudes above 3km, the wind is three to four time faster and less variable than at the current MW sized wind turbine hub height of around 100m. In addition, power generation from wind turbines installed on the ground is intermittent because local wind conditions are affected by local topography and artificial structures. The wind energy researchers and engineers are now looking for revolutionary ideas to utilize high altitude wind resources in-creasing the capabilities of wind turbine installations. This article presents and discusses several concepts for wind energy exploitation from wind at high altitudes. The concepts presented in this paper make use of lifting bodies, called wings or kites, connected to a tether that stetches into the higher regions of the atmosphere.

Effects of Dietary Energy Level and Feeding Ration on Growth and Body Composition of Nile Tilapia, Oreochromis niloticus (L.)

  • Cho, Sung-Hwoan;Jo, Jae-Yoon
    • 한국어업기술학회:학술대회논문집
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    • 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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    • pp.271-273
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    • 2000
  • Recently, possibility of low protein diet with high energy level for improvement of fish production has been proposed in several fish species, especially under restricted feeding rate, fish responded better on high energy diet than low energy diet McGoogan and Gatlin (1999) stressed another benefit of low protein diet with high energy for fish production, in terms of reduction of nitrogen waste from fish metabolism However, others reported no effect of high lipid in feed on performance of fish (Jover et al. 1999). This was probably because that energy availability o requirement for fish varied based on fish species, protein content or quality in feed, rearing water temperature condition and feeding ration. (omitted)

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복합소재를 이용한 에너지 하베스팅 기술 동향 (Recent Trends in Energy Harvesting Technology Using Composite Materials)

  • 정재환;이동민;김영준;김상우
    • 세라미스트
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    • 제22권2호
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    • pp.110-121
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    • 2019
  • Triboelectric nanogenerators and piezoelectric nanogenerators are a spotlighted energy harvesting method that converts the wasted mechanical energy from the environment into usable electrical energy. In the case of triboelectric nanogenerators, researches have been mainly focused on high permittivity and flexible polymer materials, and in the case of piezoelectric nanogenerators, researches have been focused on ceramic materials exhibiting high polarization characteristics. Recently, many researches have been conducted to improve durability and power in various environments by using composite materials which have flexible properties of polymer, high permittivity, thermal resistance and high polarization properties of ceramics. This article reviews the energy harvesting studies reported about composites materials using ceramics and polymers.

Utility AC Frequency to High Frequency AC Power Frequency Converter without Electrolytic Capacitor Link for Consumer Induction Heating Appliances

  • Sugimura, H.;Eid, A.;Lee, H.W.;Kwon, S.K.;Suh, K.Y.;Nakaoka, M.
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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    • pp.1364-1367
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    • 2005
  • In this paper, a novel prototype topology of soft switching PWM controlled high frequency AC power conversion circuit without DC voltage smoothing chemical capacitor filter link from the voltage grid of utility frequency AC power supply source with 60Hz-100V or 60Hz-200V is proposed and introduced for innovative consumer induction heating(IH) boiler applications as hot water producer, steamer and super heated vapor steamer.

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대형 강입자 충돌가속기(LHC) 실험의 자료 분산 처리 (Distributed Data Process for LHC(Large Hadron Collider) Experiment)

  • 조기현;한대희;권기환;김진철;손동철
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (1)
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    • pp.1036-1038
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    • 2005
  • 고에너지물리학의 거대강입자충돌실험(LHC)에서 생산되는 데이터양은 연간 $12\~14$PetaByte이므로 이러한 데이터를 분석하기 위해서 기존의 전산개념으로는 자료 처리하기가 불가능하다. 그러므로 새로운 개념의 대용량 자료 처리를 위한 분산 처리 시스템이 필요하며, 이와 관련하여 고에너지 물리 실험분야에서는 계층적 구조의 Tier-0, 1, 2의 지역데이터센터의 개념 및 그리드 개념을 도입하였다. LCG(LHC Computing Grid) 및 OSG(Open Science Grid)등의 그리드 팜을 이용하여 자료를 처리한다.

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전위 및 공공을 고려한 고변형률 변형에 대한 재료 시뮬레이션 (A Material Simulation of High-Strain-Rate Deformation with Dislocations and Vacancies)

  • 최덕기;유한규
    • 대한기계학회논문집A
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    • 제28권9호
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    • pp.1306-1313
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    • 2004
  • This paper addresses a theoretical approach to calculate the amount of the stored energy during high strain-rate deformations using atomistic level simulation. The dynamic behavior of materials at high strain-rate deformation are of great interest. At high strain-rates deformations, materials generate heat due to plastic work and the temperature rise can be significant, affecting various properties of the material. It is well known that a small percent of the energy input is stored in the material, and most of input energy is converted into heat. However, microscopic analysis has not been completed without construction of a material model, which can simulate the movement of dislocations and vacancies. A major cause of the temperature rise within materials is traditionally credited to dislocations, vacancies and other defects. In this study, an atomistic material model for FCC such as copper is used to calculate the stored energy.