• Title/Summary/Keyword: 헬륨

Search Result 373, Processing Time 0.032 seconds

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
    • /
    • 2003.10a
    • /
    • pp.164-167
    • /
    • 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.

  • PDF

Frequency stabilization of HeNe laser for interferometry (간섭계용 헬륨-네온 레이저의 주파수 안정화)

  • 주기남;김승우
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2003.06a
    • /
    • pp.260-263
    • /
    • 2003
  • Lasers are used as the source of the interferometers in the industrial field. These lasers need 2 requirements. The first is the narrow linewidth of laser for the long coherence length. The second is the stabilized frequency of laser for the precision measurement. Now HeNe lasers are mostly used and the frequency stability is about 10$^{-9}$ . In this paper, we construct the HeNe laser systems of frequency stabilization using typical 2 method, the beat frequency stabilization method and the intensity difference method. So, we get the frequency stabilities of 2.01$\times$10$^{-9}$ (0.1s), 3.4$\times$10$^{-9}$ (0.1s).

  • PDF

Development of Direct Analysis of Metal and Non-metal Ions in Aqueous Samples with the Moderate Power Helium Microwave Induced Plasma (중급 출력 마이크로파 유도 플라즈마를 이용한 금속 및 비금속 수용액시료의 직접 분석법의 개발)

  • Park, Yong-Nam
    • Journal of the Korean Chemical Society
    • /
    • v.35 no.6
    • /
    • pp.699-706
    • /
    • 1991
  • The moderate power (500 W) Microwave Induced Plasma was generated with helium gas and was used for the direct analysis of aqueous samples. Usually, the helium plasma obtained with a modified Beenakker type cavity forms a cylindrical one. Though, by the careful controls of gas flows, a "toroidal" shape plasma could be made but its analytical performances were found to be worse. Using the glass frit nebuliser, the detection limits for metal ions obtained were around 10~100 ppb and that for chloride was about 50ppm.

  • PDF

KSTAR NBI 이온원의 수소 및 헬륨 개스에서의 방전특성

  • 김계령;박선기;오병훈;최병호
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 1999.07a
    • /
    • pp.224-224
    • /
    • 1999
  • KSTAR 토카막의 플라즈마 가열을 위한 NBI 장치의 대전류 이온원 방전 특성을 수소와 헬륨 개스를 사용하여 조사하였다. NBI 이온원은 빔 방향과 반대로 가속되는 전자들을 저지하는 전자덤프(electron dump), 병렬로 연결된 32개의 텅스텐 필라멘트(직경 1.5nn0, 영구자석(Nd-Fe)에 의해 만들어지는 강한 cusp 자장으로 둘러싸인 플라즈마 방전실 및 120kV의 에너지를 인가하는 가속부로 이루어지는데, 최대 빔 전류 65A에서 300초의 장시간 운전을 목표로 하고 있다. 수소와 헬륨 개스 분위기에서 안정된 플라즈마를 얻을 수 있는 필라멘트 전류의 파형을 각각 구하고, 기체압력(0.01~0.4 mbar) 및 아크 전류(100~1200A에)에 따른 플라즈마 파라메타 값들을 직경 1mm의 Langmuir probe를 이용하여 측정하였다. 또한 이온원 운전에 중요한 파라메타인 방전실 내의 플라즈마 밀도 분포와 장시간 운전 가능성에 대한 조사도 수행하였다.

  • PDF

Design of a pilot-scale helium heating system to support the SI cycle (파이롯 규모 SI 공정 시험 설비에서의 헬륨 가열 장치 설계)

  • Jang, Se-Hyun;Choi, Yong-Suk;Lee, Ki-Young;Shin, Young-Joon;Lee, Tae-Hoon;Kim, Jong-Ho;Yoon, Seok-Hun;Choi, Jae-Hyuk
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.40 no.3
    • /
    • pp.157-164
    • /
    • 2016
  • In this study, researchers performed preliminary design and numerical analysis for a pilot-scale helium heating system intended to support full-scale construction for a sulfur-iodine (SI) cycle. The helium heat exchanger used a liquefied petroleum gas (LPG) combustor. Exhaust gas velocity at the heat exchanger outlet was approximately 40 m/s based on computational thermal and flow analysis. The maximum gas temperature was reached with six baffles in the design; lower gas temperatures were observed with four baffles. The amount of heat transfer was also higher with six baffles. Installation of additional baffles may reduce fuel costs because of the reduced LPG exhausted to the heat exchanger. However, additional baffles may also increase the pressure difference between the exchanger's inlet and outlet. Therefore, it is important to find the optimum number of baffles. Structural analysis, followed by thermal and flow analysis, indicated a 3.86 mm thermal expansion at the middle of the shell and tube type heat exchanger when both ends were supported. Structural analysis conditions included a helium flow rate of 3.729 mol/s and a helium outlet temperature of $910^{\circ}C$. An exhaust gas temperature of $1300^{\circ}C$ and an exhaust gas rate of 52 g/s were confirmed to achieve the helium outlet temperature of $910^{\circ}C$ with an exchanger inlet temperature of $135^{\circ}C$ in an LPG-fueled helium heating system.

Inhibition of Foodborne Pathogens on Polystyrene, Sausage Casings, and Smoked Salmon Using Nonthermal Plasma Treatments (비열 플라즈마 처리를 이용한 polystyrene, 소시지 케이싱, 그리고 훈제연어에서의 식중독균 저해)

  • Lee, Hahn-Bit;Noh, Young-Eun;Yang, Hee-Jae;Min, Sea-Cheol
    • Korean Journal of Food Science and Technology
    • /
    • v.43 no.4
    • /
    • pp.513-517
    • /
    • 2011
  • The effects of nonthermal plasma treatments against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes living on polystyrene (PS), sausage casings, and smoked salmon were investigated. Inoculated PS, casings, and salmon were treated with nonthermal plasma generated with helium (5 L/min) or with both helium (5 L/min) and oxygen (100 mL/min) at 60 Hz and 30 kV/cm for 2, 5, or 10 min. S. Typhimurium exhibited the highest sensitivity to the helium-used treatment. The greatest reduction (3.9${\pm}$0.8 log$CFU/cm^2$) was observed with L. monocytogenes on PS after the treatment with the mixed gas for 5 min. The treatment with the mixed gas inhibited L. monocytogenes on casings and salmon by 0.5${\pm}$0.3 log$CFU/cm^2$ and 1.0${\pm}$0.3 log CFU/g, respectively. Different treatment times did not result in different reductions of L. monocytogenes on both casings and salmon. The types of treatment gas and material of contamination need to be considered for evaluating the antimicrobial effects of nonthermal plasma treatments.

Simulation Study of Hydrogen Liquefaction Process Using Helium Refrigeration Cycle (헬륨 냉동사이클을 이용한 수소액화 공정모사 연구)

  • Park, Hoey Kyung;Park, Jin-Soo
    • Applied Chemistry for Engineering
    • /
    • v.31 no.2
    • /
    • pp.153-163
    • /
    • 2020
  • Compared to gaeous hydrogen, liquid hydrogen has approximately 1/800 volume, 800 times higher volumetric energy density at the same pressure, and the advantage of lower explosion risk and easier transportation than gaseous hydrogen. However, hydrogen liquefaction requires larger scale facility investment than simple compression storage method. Therefore, the research on energy-saving hydrogen liquefaction processes is highly necessary. In this study, helium/neon (mole ratio 80 : 20) refrigeration cycle was investigated as the main refrigeration process for hydrogen liquefaction. Process simulation for less energy consumption were carried out using PRO/II with PROVISION V10.2 of AVEVA. For hydrogen liquefaction, energy consumption was compared in three cases: Using a helium/neon refrigerant cycle, a SMR+helium/neon refrigerant cycle, and a C3-MR+helium/neon refrigerant cycle. As a result, the total power consumptions of compressors required to liquefy 1 kg of hydrogen are 16.3, 7.03 and 6.64 kWh, respectively. Therefore, it can be deduced that energy usage is greatly reduced in the hydrogen liquefaction process when the pre-cooling is performed using the SMR process or the C3MR process, which have already been commercialized, rather than using only the helium/neon refrigeration cycle for the hydrogen liquefaction process.

위성 발사체 추진제 가압용 열교환기 기초 설계

  • 이희준;한상엽;정용갑;길경섭;하성업;김병훈
    • Bulletin of the Korean Space Science Society
    • /
    • 2004.04a
    • /
    • pp.74-74
    • /
    • 2004
  • 액체추진제를 사용하는 위성 발사체의 경우 추진제탱크에 저장된 추진제를 추력을 발생하는 연소실에 공급하기 위하여 헬륨 등의 가압제를 사용한다. 본 연구에서는 액체추진제 로켓엔진의 산화제인 극저온의 액체산소를 저장하고 있는 탱크 내부에 설치된 별도의 탱크에 저장된 극저온/고압의 헬륨을 고온으로 열팽창 시켜 추진제 탱크로 재유입하여 추진제를 가압하는 시스템에 사용되는 가압제 열팽창용 열교환기의 개발을 위한 기초 설계를 수행하였다. (중략)

  • PDF

거시적 양자현상과 초전도성

  • Lee, Jong-Yong;Seo, Jeong-Dae;Seong, Geon-Yong;Gang, Gwang-Yong
    • Electronics and Telecommunications Trends
    • /
    • v.6 no.3
    • /
    • pp.13-22
    • /
    • 1991
  • 물리계에는 특이한 성질을 갖는 몇몇 부류(class), 예를 들면 초전도체, 초유체 헬륨, 준-일차원 금속등이 있다. 그리고 계를 정의하기 위하여는 계가 열평형에 도달하는 속도뿐만 아니라 거시적 점유상태를 규정하는 것이 필요하다. 그리하여 쌍생성(electrons pairing) 에 의한 초전도현상, 초유체 헬륨의 $\lambda$-전이, 준-일차원 금속의 Peierls전이와 같은 물리적 특성을 단일 양자상태의 거시적 점유로부터 추론하였다.