• 제목/요약/키워드: High Vacuum

검색결과 3,513건 처리시간 0.031초

진공침탄 공정기술을 이용한 자동변속기 부품 개발 (Development of Automatic Transmission Parts by Using Vacuum Carburizing Heat-treatment Technology)

  • 이원범;문경일;조용기;임경묵;변상교
    • 한국표면공학회지
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    • 제43권5호
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    • pp.211-216
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    • 2010
  • Vacuum carburizing process is well known process for its environment-friendly, low-cost, high-quality characteristics, compared with gas carburizing. In this study, a research was carried out to develop a process of vacuum carburizing for essential components of automotive transmission that is difficult to control its distortion. As a result, vacuum carburizing process is superior to gas carburizing in terms of cost, environment and quality.

Effect of Powder Size on Infiltration Height in Producing MgO Reinforced Al Matrix Composite by Vacuum Infiltration Method

  • Calin, Recep;Citak, Ramazan
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.1271-1272
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    • 2006
  • The vacuum infiltration method is one of the composite producing methods. There are several parameters in composite production by vacuum infiltration. One of them is particle size of reinforcement in particulate reinforced composites. In this study, MgO powder and Al were used as reinforcement and matrix respectively. MgO powders with different size and amount to give same height were filled in quartz tubes and liquid metal was vacuum infiltrated into the MgO powder under same vacuum condition and for same time. Infiltration height was measured and microstructure and fracture behavior of composite were investigated. It has been found that infiltration height and fracture strength were increased with particulate reinforcement sizes. It has also been determined that molten metal temperature facilitates infiltration.

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ICCD Observation on Discharge Characteristics of 42-in. AC Plasma Display Panel Fabricated by Vacuum Sealing Method

  • Park, Choon-Sang;Tae, Heung-Sik;Kwon, Young-Kuk;Heo, Eun-Gi;Lee, Byung-Hak
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.320-323
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    • 2007
  • The vacuum sealing method is adopted to minimize the residual impurity gas by enhancing a base vacuum level, and the resultant changes in the reset, address, and sustain discharge characteristics, such as a firing voltage, IR emission, and ICCD image, were examined in comparison with the conventional sealing method in the 42-in. AC-PDP. In the PDP cells fabricated by the vacuum sealing method, the ICCD observation illustrates that the discharge is initiated and extinguished very fast and its IR emission intensity is high.

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탄소나노튜브 전극으로부터 전자방출에 의한 진공도 측정 (Measurement of Vacuum Pressure by Electron Emission from Carbon Nanotube Emitters)

  • 김성진;조규환;김성엽;전재옥;이상훈;최복길
    • 한국전기전자재료학회논문지
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    • 제18권5호
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    • pp.396-400
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    • 2005
  • Carbon nanotubes (CNTs) have been well known as electron emitters for field emission applications like FEDs. In this work, we propose as new application a vacuum sensor using CNTs and discuss its current-voltage characteristics as a function of vacuum pressure. The proposed sensor, based on electrical discharge theories in air gap well-known as Townsend theory and as Paschen's law, works by figuring out the variation of the dark current and the initial breakdown voltage depending on the vacuum pressure of air which can ionize through collisions with the electrons accelerated by high electric field.

수치해석을 통한 진공유리 제작 및 성능실험에 관한 연구 (A Study on Performance Test and Fabrication of Vacuum Glazing with Numerical Analysis)

  • 황일선;이영림
    • 설비공학논문집
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    • 제25권6호
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    • pp.303-309
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    • 2013
  • For air-tight modern buildings, secondary damage is likely to occur due to condensation in the relatively high heat-transmission windows since water vapor is not easy to discharge. Therefore, in this study, condensation performance of vacuum glazing was numerically analysed, compared with that of ordinary glass and confirmed experimentally by three sheets of vacuum glazing manufactured. The results show that the heat transmission coefficient of the vacuum glazing whose internal pressure is $10^{-3}$ torr was as low as about $5.7W/m^2{\cdot}K$. Thus, the condensation performance as well as the adiabatic performance was greatly improved compared to that of the ordinary glass.

고진공 및 극저온 달의 지상 환경 재현을 위한 지반열진공챔버 운영 효율성 평가 (Assessment of DTVC Operation Efficiency for the Simulation of High Vacuum and Cryogenic Lunar Surface Environment)

  • 진현우;정태일;이장근;신휴성;유병현
    • 한국지반공학회논문집
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    • 제38권12호
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    • pp.125-134
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    • 2022
  • 세계 우주 기관들로 조직된 국제 우주탐사 협력 그룹이 발간하는 글로벌 우주탐사 로드맵에서는 미래 달 탐사 방향과 달 자원 활용을 위한 거주 계획을 반영하는 등 달은 심우주 탐사를 위한 전초기지로 주목받고 있다. 따라서 달 행성 지반 환경 재현 인프라 기술은 미래 달 지상 탐사를 위해 필요한 다양한 장비들의 성능검증에 활용될 수 있다. 본 연구에서는 달 착륙 및 기지 건설 후보지인 달 남극 영구음영지역의 고진공 및 극저온 지상 환경을 재현하고자 하였다. 현재까지 달 지상 환경 재현을 위한 효율적 장비 운용 프로세스는 제시되지 못한 실정으로, 본 연구에서는 파일럿 지반열진공챔버에 인공월면 지반을 조성한 뒤 다양한 진공 환경에 대해 일방향 지반냉각 실험을 진행하고 이를 평가하였다. 냉각효율 및 장비 안정성 측면에서 가장 유리한 진공 환경은 30-80 mbar인 것으로 파악되었으나, 고진공 환경에서 얼음이 승화되지 않기 위한 극저온의 온도를 구현하기 위해서는 주변부 냉각이 추가적으로 요구되었다. 이를 위해 본 연구에서는 동결비 개념을 적용해 효율적인 주변부 냉각 가동 시점을 제안하였다.

비정질 실리콘을 이용한 다층 유전 박막의 전기적 특성에 관한 연구 (Study on Electric Charactreistics of Multi-dielectric Thin Films Using Amorphous Silicon)

  • 정희환;정관수
    • 한국진공학회지
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    • 제3권1호
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    • pp.71-76
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    • 1994
  • The electrical characteristics of the capacitor dielectric films of amorphous silicon-nit-ride-oxide(ANO) structures are compared with the capacitor dielectric films of oxide-nitride-oxide (ONO) structrues The electrical characteristics of ONO and ANO films were evaluated by high frequency(1 MHz) C-V high frequency C-V after constant voltage stree I-V TDDB and refresh time measurements. ANO films shows good electrical characteristics such as higher total charge to breakdown storage capacitance and longer refresh time than ONO films. Also it makes little difference that leakage current and flat band voltage shyift(ΔVfb)of ANO ana ONO films.

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Transparent Conductor-embedding Si for High-performing Hetrojunction Photoelectric Devices

  • Kim, Joondong
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.444.2-444.2
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    • 2014
  • Transparent conductors (TCs) are typically applied as an ohmic contact layer for photoelectric devices. Recent researches have illuminated a unique rectifying-junction design between a transparent conductor and a semiconductor layer. This approach may lead a significant reduction of device-fabrication steps and cost. A high-performing heterojunction device is presented, which provided significant photoelectric responses. This covers the fabrication processes, rectifying-junction formations and device analyses.

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