• Title/Summary/Keyword: 헬륨주입

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KSR-III Helium Fill/prepressurization Umbilical Valve Development (KSR-III 헬륨 주입/선가압 엄비리칼 밸브 개발)

  • 정영석;조기주;조인현;오승협
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.164-167
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    • 2003
  • In generally, Gas fill & drain valve is used in filling Gases to tank on high pressure in launcher The valve is quick coupling type and is separated by manual or remote control. In KSR-III, He gas fill & drain valve separated by remote control is used. In this paper, that are explained about the design specification, the test procedure, the autonomous test result and the flight test result.

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Nanocrystalline-Si Thin Film Deposited by Inductively Coupled Plasma Chemical Vapor Deposition (ICP-CVD) at $150^{\circ}C$ (극저온($150^{\circ}C$)에서 ICP-CVD로 증착한 Nanocrystalline-Si 박막)

  • Park, Snag-Geun;Han, Sang-Myeon;Shin, Kwang-Sub;Han, Min-Koo
    • Proceedings of the KIEE Conference
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    • 2005.11a
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    • pp.12-14
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    • 2005
  • Inductively Coupled Plasma Chemical Vapor Deposition(ICP-CVD)를 이용하여 공정온도 $150^{\circ}C$에서 Nanocrystalline silicon (nc-Si) 박막을 증착하였다. 실험에서 헬륨(He)가스, 수소($H_2$)가스 그리고 헬륨(He)과 수소($H_2$)의 혼합가스로 희석한 사일렌($SiH_4$)을 반응가스로 이용하였다. 이 혼합가스는 3sccm의 사일렌($SiH_4$)에 헬륨(He)과 수소($H_2$)의 주입율을 20sccm에서부터 60sccm까지 변화시켜 조건을 달리하여 사용했다. 증착한 Nc-Si 박막을 X-ray diffraction (XRD)으로 분석하여 각각의 조건에 대한 Nc-Si 박막의 속성을 연구하였다. 헬륨(He) 또는 수소($H_2$) 혼합가스의 주입율이 커지면서 <111>과 <222>의 최고점(peak)이 더 높아졌으며 결정화 되지 않고 비결정질로 남아 있는 성장층(incubation layer)이 얇아졌다. 이 결과는 nc-Si를 증착할 때 사용한 수소($H_2$) 플라즈마와 헬륨(He) 플라즈마의 효과로 설명할 수 있다. 실험을 통해 ICP-CVD로 증착한 nc-Si 박막을 박막 전계효과트랜지스터 (TFT)에서 우수한 특성의 전자수송층(active layer)으로 사용할 수 있는 것을 확인하였다.

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Uniformity Control by Using Helium Gas in the Large Area Ferrite Side Type Inductively Coupled Plasma

  • Han, Deok-Seon;Bang, Jin-Yeong;Jeong, Jin-Uk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.517-517
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    • 2012
  • 높은 전력 효율과 간단한 매칭 네트워크의 구조 등 많은 장점을 갖고 있는 직경 560 mm 페라이트 챔버가 대면적 웨이퍼에 대응하기 위해 개발 되었다. 플라즈마 소스원이 챔버 외곽에 위치해 있는 구조적 특성으로 인하여 아르곤 가스 방전 시 플라즈마 밀도 분포는 챔버 중앙부가 낮게 나타나는 볼록한 모양으로 형성 되는데 헬륨 가스를 적절히 혼합할 시에 밀도 분포가 변화가 관찰된다. 헬륨 가스 혼합 비에 따라 플라즈마 밀도 분포는 균일도가 매우 높아 질 수 있으며 60% 이상의 혼합비에서는 중앙 부분의 밀도가 최대치로 역전되는 오목한 밀도 분포가 나타나기도 한다. 이는 헬륨 가스의 대표적인 특징인 가벼운 질량과 높은 이온화 에너지 등에 기인하는데 이러한 특징을 갖는 헬륨 가스를 주입하게 되면 전자의 energy relaxation length가 늘어나게 되며 ambipolar diffusion 계수가 증가하게 된다. 랑뮈어 프로브를 이용하여 측정된 플라즈마 밀도 분포 변화는 앞서 계산 된 energy relaxation length 및 ambipolar diffusion 계수들의 변화로 설명된다.

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HELIUM CONCENTRATION DECREASE DUE TO AIR ENTRAINMENT INTO GLASS FIBER COOLING UNIT IN A HIGH SPEED OPTICAL FIBER DRAWING PROCESS (광섬유 고속인출공정용 유리섬유 냉각장치 내 공기유입에 의한 내부헬륨농도 저하현상 연구)

  • Kim, K.;Kim, D.;Kwak, H.S.;Park, S.H.;Song, S.H.
    • Journal of computational fluids engineering
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    • v.15 no.4
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    • pp.92-98
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    • 2010
  • In a modern high speed drawing process of optical fibers, it is necessary to use helium as a cooling gas in a glass fiber cooling unit in order to sufficiently cool down the fast moving glass fiber freshly drawn from the heated silica preform in the furnace. Since the air is entrained unavoidably when the glass fiber passes through the cooling unit, the helium is needed to be injected constantly into the cooling unit. The present numerical study investigates and analyzes the air entrainment using an axisymmetric geometry of glass fiber cooling unit. The effects of helium injection rate and direction on the air entrainment rate are discussed in terms of helium purity of cooling gas inside the cooling unit. For a given rate of helium injection, it is found that there exists a certain drawing speed that results in sudden increase in the air entrainment rate, which leads to the decreasing helium purity and therefore the cooling performance of the glass fiber cooling unit. Also, the helium injection in aiding direction is found to be more advantageous than the injection in opposing direction.

기체 크로마토그래피법을 이용한 수소동위원소 분리기술

  • 김광락;구제휴;나정원;정흥석;성기웅;김용익
    • Nuclear Engineering and Technology
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    • v.28 no.1
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    • pp.93-101
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    • 1996
  • 수소동위원소의 실험과 취급 및 삼중수소 제거시설의 운용이나 더 나아가서 핵융합소재의 관리기술을 위해서는 수소동위원소분만 아니라 그들의 이성질체들에 대한 정성 및 정량분석이 필수적이며 이를 위해 기체크로마토그래피 분리법이 중요한 분석수단으로 활용되어오고 있다. 본 연구에서는 고순도 $H_2및$ $D_2의$ 수소동위원소 기체를 대상으로 하고 상용의 기체크로마토그래피 분석기를 사용하여 분리컬럼 분위기를 액체질소온도로 유지하고 헬륨 케리어기체를 특별제작된 진공-시료주입장치를 통해 펄스주입하여 크로마토그래피 분리실험을 수행하였다. 10%함량의 염화망간으로 부분 비활성화 시킨 산화알루미늄을 고정상으로 선정하여 이성질체의 분리를 억제할 수 있었으며 흡착후 분리용리시간이 단축된 비교적 좋은 수소동위원소 분리조건을 실증하므로서, 저농도 수소동위원소의 정량분석과 고순도 수소동위원소의 분리 및 농축기술 개발을 위한 기초를 마련하였다.

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Computational Thermo-Fluid Analysis for the Effects of Helium Injection Methods on Glass Fiber Cooling Process in an Optical Fiber Manufacturing System (광섬유 냉각장치의 헬륨 주입기 설계를 위한 전산열유동해석)

  • Park, Shin;Kim, Kyoungjin;Kim, Dongjoo;Park, Junyoung;Kwak, Ho Sang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.2
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    • pp.124-130
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    • 2014
  • In a mass manufacturing system of optical fibers, the sufficient cooling of glass fibers freshly drawn from a draw furnace is essential, asinadequately cooled glass fibers can lead to poor resin coating on the fiber surface and possibly fiber breakage during the process. In order to improve fiber cooling at a high drawing speed, it is common to use a helium injection into a glass fiber cooling unit in spite of the high cost of the helium supply. The present numerical analysis carried out three-dimensional thermo-fluid computations of the cooling gas flow and heat transfer on moving glass fiber to determine the cooling performance of glass fiber cooling depending on the method of helium injection. The results showed that afront injection of helium is most effective compared to a uniform or rear injection for reducing air entrainment into the unit and thus cooling the glass fibers at a high fiber drawing speed. However, above a certain amount of injected helium, there was no more increase of the cooling effect regardless of the helium injection method.

COMPUTATIONAL ANALYSIS ON THE COOLING PERFORMANCE OF GLASS FIBER COOLING UNIT WITH HELIUM GAS INJECTION (헬륨가스 주입식 유리섬유 냉각장치의 냉각성능 해석)

  • Oh, I.S.;Kim, D.;Umarov, A.;Kwak, H.S.;Kim, K.
    • Journal of computational fluids engineering
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    • v.16 no.4
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    • pp.110-115
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    • 2011
  • A modern optical fiber manufacturing process requires the sufficient cooling of glass fibers freshly drawn from the heated and softened silica preform in the furnace, since the inadequately cooled glass fibers are known to cause improper polymer resin coating on the fiber surface and to adversely affect the product quality of optical fibers. In order to greatly enhance the fiber cooling effectiveness at increasingly high fiber drawing speed, it is necessary to use a dedicated glass fiber cooling unit with helium gas injection between glass fiber drawing and coating processes. The present numerical study features a series of three-dimensional flow and heat transfer computations on the cooling gas and the fast moving glass fiber to analyze the cooling performance of glass fiber cooling unit, in which the helium is supplied through the discretely located rectangular injection holes. The air entrainment into the cooling unit at the fiber inlet is also included in the computational model and it is found to be critical in determining the helium purity in the cooling gas and the cooling effectiveness on glass fiber. The effects of fiber drawing speed and helium injection rate on the helium purity decrease by air entrainment and the glass fiber cooling are also investigated and discussed.

THERMO-FLUID ANALYSIS ON THE HELIUM INJECTION COOLING OF GLASS FIBER FOR HIGH SPEED OPTICAL FIBER MANUFACTURING (광섬유 고속생산용 헬륨 주입식 유리섬유 냉각공정에 대한 열유동 해석)

  • Oh, I.S.;Kim, D.;Kwak, H.S.;Kim, K.
    • 한국전산유체공학회:학술대회논문집
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    • 2011.05a
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    • pp.92-95
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    • 2011
  • In manufacturing optical fibers, the process starts with the glass fiber drawing from the heated and softened silica preform in the furnace, and the freshly drawn glass fiber is still at high temperature when it leaves the glass fiber drawing furnace. It is necessary to cool down the glass fiber to the ambient temperature before it then enters the fiber coating applicator, since the hot glass fiber is known to cause several technical difficulties in achieving high quality fiber coating. As the fiber drawing speed keeps increasing, a current manufacturing of optical fibers requires a dedicated cooling unit with helium gas injection. A series of three-dimensional flow and heat transfer computations are carried out to investigate the effectiveness of fiber cooling in the fiber cooling unit. The glass fiber cooling unit is simplified into the long cylindrical enclosure at which the hot glass fiber passes through at high speed, and the helium is being supplied through several injection slots of rectangular shape along the cooling unit. This study presents and discusses the effects of helium injection rates on the glass fiber cooling rates.

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The Development of Pressure Regulator of Propellant Tank for KSR-III (KSR-III 추진제 탱크 압력 조절용 레귤레이터 개발)

  • 정영석;조기주;조인현;김용욱;오승협
    • Journal of the Korean Society of Propulsion Engineers
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    • v.6 no.4
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    • pp.47-58
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    • 2002
  • The pressure regulator has been developed as a pressure-control device of propellant tank in KSR-III. The pressurization system of KSR-III is a basic pressurization system composed of pressurant, He tank and propellant tank. The pressure-control regulator is the most important part of gas-pressurized feed system along with He tank, pyrovalve and He fill valve. The first model of the regulator is tested to satisfy in leakage, strength and basic performance. The second model is tested in the overall test of the KSR-III propulsion system using water. From the test result of the second model, we conclude that the capacity of valve(Cv) must be increased in real system. The third model is modified and tested in the overall test of KSR-III propulsion system using propellant. Finally, the pressure-control regulator is qualified from firing test.

Efficient Stripping of High-dose Ion-implanted Photoresist in Supercritical Carbon Dioxide (초임계 이산화탄소를 이용한 고농도이온주입 포토레지스트의 효율적인 제거)

  • Kim, Do-Hoon;Lim, Eu-Sang;Lim, Kwon-Taek
    • Clean Technology
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    • v.17 no.4
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    • pp.300-305
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    • 2011
  • A mixture of supercritical carbon dioxide and a co-solvent was employed to strip a high-dose ion-implanted photoresist (HDIPR) from the surface of semiconductor wafers. The stripping efficiency was highly improved by the physical force generated from a ultrasonication tip inside the reactor. In addition, helium gas was injected in the reactor as a barrier gas before the introduction of pure supercritical $CO_2$ ($scCO_2$), which reduced the rinsing time significantly. The effect of co-solvents on the stripping efficiency was investigated. The wafer surfaces were analyzed by scanning electron microscopy and by an energy dispersive X-ray spectrometer.