• 제목/요약/키워드: Vacuum Characteristics

검색결과 2,157건 처리시간 0.03초

저진공상태에서 노즐 팽창비와 비열비에 따른 마이크로 노즐의 특성 연구 (Characteristic Study of Micro-Nozzles according to the Ratios of Nozzle Expansion and Specific heats in low vacuum condition)

  • 김연호;정성철;허환일
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.249-252
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    • 2006
  • We conducted the experiment to analyze characteristics of micro-nozzle using different cold gas under two different nozzle expansion ratios in low vacuum condition. We measured thrust and chamber pressure and mass flow rate under low vacuum condition, and then compared them with those in ambient pressure.

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고진공 영역의 진공게이지 특성연구 (The Study of Vacuum Gauge Characteristics in the High Vacuum Range)

  • 홍승수;신용현;임재영;박재홍;이철로;정광화
    • 한국진공학회지
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    • 제2권1호
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    • pp.1-8
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    • 1993
  • 당 연구실에서 개발 제작된 동적교정방법을 이용한 고진공표준기를 사용하여 10-6∼10-3torr 영역에서 가장 널리 쓰이는 spinning rotor gauge와 열음극전리 진공게이지들의 특성을 상품화되어 사용되는 방법대로 측정하여 조사하여 보았다. 게이지들의 직선성, 단기간(15일)에 행해진 반복측정에서의 scattering을 조사하였고 또한 N2, CO, He, H2, O2, Ar 가스에 대한 감도와 압력을 올릴 때와 내릴 때의 hysteresis를 조사하였다.

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화학기상증착법(CVD)을 이용한 진공 박막 공정기술 (Thin Film Vacuum Process Technology via Chemical Vapor Deposition Methods)

  • 홍완식
    • 진공이야기
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    • 제1권3호
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    • pp.9-13
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    • 2014
  • Vacuum growth of thin films via chemical vapor deposition (CVD) methods has been extensively used in modern semiconductor and flat panel display industries. The CVD processes have a wide range of variation and are categorized according to their working conditions, power sources, precursor materials, and so forth. Basic components and process steps common to all CVD branches are discussed. In addition, characteristics and applications of two major CVD techniques - LPCVD and PECVD - are reviewed briefly.

A Study of the Transient Flow Characteristics of a Vacuum Ejector-Diffuser System.

  • ;김희동
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2769-2774
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    • 2007
  • In vacuum ejector-diffuser systems where a finite volume secondary chamber is used, the secondary jet exhibits transient characteristics during start-up. A steady state is achieved after some time in which mass entrainment prevails indefinitely inside the ejector, though there is no flow from the secondary chamber. An attempt is made in this work to study the infinite entrainment of secondary jet into the primary jet from a finite secondary chamber, with the help of a computational fluid dynamics method. The present study is also intended to identify the operating range of vacuum ejector-diffuser systems where the steady flow assumption can be applied without uncertainty. The results obtained show that the only condition in which an infinite mass entrainment is possible is the generation of a re-circulation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium at this point. Steady flow assumption is valid only after this point.

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설계변수에 따른 진공인터럽터용 종자계방식 전극의 아크특성에 관한 연구 (A Study on the Arc Characteristics of Axial Magnetic Field Type Electrode for Vacuum interrupter by Desing Parameters)

  • 김성일;박흥태;안희일;서정민
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 B
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    • pp.672-674
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    • 2001
  • Axial magnetic field(AMF) type electrode can increase the interrupting capability of vacuum interrupters. But, this interrupting capability vary with design parameters such as shape of electrode, slits of contact, material of contact and so on. In this paper, shown arc characteristics of unipolar axial magnetic field type electrode for vacuum interrupter by design parameters such as shape of contact slits and diameter of contact. And, confirmed vacuum arc configuration by individual design parameter using high speed camera.

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농산물의 저온진공건조 열적 특성에 관한 연구 - 고추를 중심으로 - (A Study on the Thermal Characteristics of Agriculture Products in the Process of Low Temperature Vacuum Drying - With Cayenne as the Object Product for Drying -)

  • 최순열
    • 동력기계공학회지
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    • 제5권1호
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    • pp.44-49
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    • 2001
  • Low temperature vacuum drying technique shows very excellent energy efficiency and prominent drying performances compared with the conventional hot air drying technique. This study was focused on the thermal characteristics of the low temperature vacuum drying technique. From the results of this study, it was confirmed that the time consumption for drying with the new drying technique could be shortened to about 1/3 of the time consumption with the conventional hot air drying technique under the same drying conditions for wet products. Also, the maximum drying rate with the new drying technique reached to about $0.35kg/m^2h$ at about 400% of moisture content.

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진공 펌프 성능 평가 계통의 동적 응답 (Dynamic Response of the System for Vacuum Pump Performance Evaluation)

  • 심우건;임종연
    • 대한기계학회논문집B
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    • 제28권11호
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    • pp.1359-1367
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    • 2004
  • The demand of vacuum pump has been increased in the process of semi-conduct manufacturing, as a core component. The response of the system for vacuum pump performance test can be utilized to assess the system and to obtain the reliability of the apparatus for the test. The system consists of gas supply tank, pressure chamber, measurement chamber and transmission line. Transient analysis for compressible fluid has been conducted to evaluate the dynamic characteristic of the volume terminated transmission line. Numerical approach based on the method of characteristics is used for the analysis. The response is evaluated with the important parameters for the system: i.e., length and diameter of the line, volume of the terminal tank. Using the numerical results, pumping speeds are calculated and then compared to the experimental results.

고진공용 자성유체시일이 마찰 토오크 특성에 관한 실험적 연구 (Experimental Study on the Friction Torque Characteristics of Magnetic Fluid Seals for High Vacuum System)

  • 김청균;나윤환;김한식
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1996년도 제24회 춘계학술대회
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    • pp.145-152
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    • 1996
  • This paper deals with an experimental study on the f~iction torque characteristics of magnctic fluid seals for various oil temperatures, rotating speeds, and vacuum pressures. The friction torque of MFS was measured by high response torque meter. The experimental results show that, as the rotating speed increases, the fi'iction torque of MFS increases and as the oil temperature increases, the friction torque of MFS decreases. Also, the experimental results show that the friction torque of Model II is 1.73 ~ 2.56, 2.0 ~ 2.89, 2.0 - 3.25 times larger than those of Model I under the atmospheric pressure, vacuum pressure(10$^{-4}$ and 10$^{-6}$ torr), respectively.

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고진공 자성유체시일의 성능 특성에 관한 실험적 연구 (Experimental Study on the Performance Characteristics of Magnetic Fluid Seals for a High Vacuum System)

  • 김청균;나윤환
    • Tribology and Lubricants
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    • 제13권2호
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    • pp.105-111
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    • 1997
  • This paper deals with an experimental study on the friction torque characteristics of magnetic fluid seals for various oil temperatures, rotating speeds, and vacuum pressures. The friction torque of MFS was measured by high response torque meter. The experimental results show that, as the rotating speed increases, the friction torque of MFS increases and as the oil temperature increases, the friction torque of MFS decreases. Also, the experimental results show that the friction torque of Model-II is 1.73~2.56, 2.0~2.89, 2.0~3.25 times higher than those of Model-I under the atmospheric pressure, vacuum pressure ($10^{-4} and 10^{-6}$ torr), respectively.

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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