• 제목/요약/키워드: Barrier energy

검색결과 823건 처리시간 0.038초

차세대 Barrier 물질 개발 동향 (A Practical Engineering for Advanced Barrier Materials: A Brief Review)

  • 안희성;이종석
    • 멤브레인
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    • 제25권2호
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    • pp.85-98
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    • 2015
  • 고분자의 용이한 가공성과 우수한 투명성, 그리고 합리적인 비용 효율로 인해 식품 포장 산업에서 금속이나 유리용기들을 고분자 기반의 포장 소재들로 대체하려는 경향이 전 세계적으로 널리 퍼지고 있다. Barrier 고분자들은 산소, 이산화탄소, 수증기 등 대기 가스에 대한 낮은 투과성을 나타내고 있어 식품 포장 산업 이용에 유용하다. 이러한 식품 포장 산업의 전반적인 추세와 함께, 산소에 민감한 주스, 착향 음료, 그리고 에너지 음료 등 새로운 식품 산업의 성장으로 인해 고성능의 barrier 특성, 특히 $O_2$$CO_2$에 대해 낮은 투과성을 지닌 고분자 포장 소재의 개발이 시급한 상황이다. 기존의 고분자에 기반한 barrier의 성능 향상은 새로운 식품 포장 산업에 급격한 변화를 줄 것이다. 본 총설에서는 (1) antiplasticization을 유도한 barrier 소재들, (2) antiplasticization과 crystallization을 사용한 barrier 성능 상승 효과, (3) 새로운 barrier 고분자들, (4) 나노합성 소재, (5) 혼합 고분자 등과 더불어, 차세대 포장 소재들의 특성 분석을 소개하고자 한다.

배수갑문 접근배수로 유입흐름의 에너지 감세량 추정 (Energy Dissipation of Inflow in the Upstream Channel of Sluice Gate of Tial Barrier Dam)

  • 조진훈;박상현
    • 한국관개배수논문집
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    • 제6권1호
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    • pp.9-19
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    • 1999
  • Energy dissipation of inflow in the upstream channel of sluice gate in Sihwa tidal barrier dam was estimated by hydraulic model study for the preliminary step to examine the erodibility of channel. The sluice gates is operated not only during the ebb tide

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Tailor Welded Blanks를 이용한 자동차용 부품개발 (Development of Automotive Part using Tailor Welded Blanks)

  • 이승희;전병희;김헌영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1998년도 춘계학술대회논문집
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    • pp.40-44
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    • 1998
  • In this study, the subframe of passenger car is developed by typical analysis and carsh simulations. According this results, energy absorption and barrier froce is very important to control passenger safety and deformation shape. For that purpose, it is most effective to absorb energy more tailor welded blanks(TWB) subframe than non-TWB. The subframe with TWB is simulated, in which reduced stamping parts, weight reduction and cost down.

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Pulse Density Modulated Zero Voltage Soft-Switching High-Frequency Inverter with Single Switch for Xenon Gas Dielectric Barrier Discharge Lamp Dimming

  • Sugimura, Hisayuki;Suh, Ki-Young;Lee, Hyun-Woo;Nakaoka, Mutsuo
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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    • pp.391-394
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    • 2006
  • This paper presents soft switching zero voltage switching high frequency inverter for rare gas fluorescent lamp using dielectric-barrier discharge phenomenon. The simple high-frequency inverter can completely achieve stable zero voltage soft switching (ZVS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZVS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this high frequency Inverter are illustrated as compared with computer simulation results and experimental ones. Its light dimming characteristics due to power regulation scheme are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proven from the practical point of view.

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중저준위방사성폐기물 처분장 인공방벽의 핵종유출 저지능 평가 (Performance Assessment of Engineered Barrier for Retardation of Radionuclide Release in a Low- and Intermediate-Level Radioactive Waste Repository)

  • 조원진;이재완;한필수;박헌휘
    • Nuclear Engineering and Technology
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    • 제25권3호
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    • pp.447-456
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    • 1993
  • 중저준위 방사성폐기물처분장 인공방벽의 핵종유출 저지능을 평가할 수 있는 단순 모델이 제안되었다. 이 모델은 현재 우리나라에서 제안되고 있는 처분장 개념을 고려하여 고안되었으며, 인공방벽의 설계에 적합한 설계 기준 유출 과 인공방벽 성능평가에 적합한 현실적 유출 두 가지 경우를 다루고 있다. 모델의 유용성을 보이기 위해 화학적 특성이 다른 다섯 핵종에 대해 모의 계산을 수행하고 그 결과를 분석하였다.

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Electrical characteristics and deep-level transient spectroscopy of a fast-neutron-irradiated 4H-SiC Schottky barrier diode

  • Junesic Park;Byung-Gun Park;Hani Baek;Gwang-Min Sun
    • Nuclear Engineering and Technology
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    • 제55권1호
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    • pp.201-208
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    • 2023
  • The dependence of the electrical characteristics on the fast neutron fluence of an epitaxial 4H-SiC Schottky barrier diode (SBD) was investigated. The 30 MeV cyclotron was used for fast neutron irradiation. The neutron fluences evaluated through Monte Carlo simulation were in the 2.7 × 1011 to 1.45 × 1013 neutrons/cm2 range. Current-voltage and capacitance-voltage measurements were performed to characterize the samples by extracting the parameters of the irradiated SBDs. Neutron-induced defects in the epitaxial layer were identified and quantified using a deep-level transient spectroscopy measurement system developed at the Korea Atomic Energy Research Institute. As the neutron fluence increased from 2.7 × 1011 to 1.45 × 1013 neutrons/cm2, the concentration of the Z1/2 defects increased by approximately 20 times. The maximum defect concentration was estimated as 1.5 × 1014 cm-3 at a neutron fluence of 1.45 × 1013 neutrons/cm2.

고온초전도 변압기용 극저온 절연기술 (Cryogenic Insulation Technique for HTS Transformer)

  • 김상현;천현권
    • 한국초전도ㆍ저온공학회논문지
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    • 제8권1호
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    • pp.45-48
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    • 2006
  • In the response to the demand for electrical energy , much effort was given to develop and commercialize high temperature superconducting (HTS) power equipments has been made around the world. Especially, HTS transformer is one of the most promising devices . but the cryogenic insulation technology should be established during development Hence many types of dielectric tests should be carried out to understand the dielectric phenomena at cryogenic temperature and to gather various dielectric data. Among the many types dielectric tests . the characteristic of barrier effect were conducted using simulated electrode after analysing the insulating configuration of HTS transformer main winding. The influence of a barrier on the dielectric strength was measured according to the position of the harriet the number of the barrier and thickness or the barrier. It was shown that the effectiveness . namely the ratio of the breakdown voltage in presence of barrier to the voltage without barrier, is highest when the barrier is placed at the needle electrode side. On the contrary, in the case of having the barrier between the electrodes, the harrier was placed between the electrodes the characteristic was even improved slightly.

용사 열차폐 코팅층의 두께가 열응력에 미치는 영향 (A Study on the Effects of the Thickness of Top Coat on the Thermal Stresses of a Sprayed Thermal Barrier Coating)

  • 김형남;양승한
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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    • pp.223-225
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    • 2004
  • Based on the principle of complementary energy an analytical method is developed for determining thermal stress distribution in an thermal barrier coating. This method gives the stress distributions which satisfy the stress-free boundary conditions at the edge. Numerical examples are given in order to verify the method and to investigate the thickness effects of the ZrO$_2$-8wt%Y$_2$O$_3$ top coat on the integrity of thermal barrier coating consisted of IN738LC substrate and MCrAlY bond coat.

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