• Journal of the Korean Physical Society
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• 제80권
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• pp.1-12
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• 2022

Over the past few decades, tetrafluoroethane (TFE, R134a Freon)-based gases have been widely used in the operation of phenolic resistive plate chambers (RPCs) in many high-energy experiments. However, TFE has a high global warming potential (GWP); therefore, a search for new eco-friendly gases to replace traditional TFE-based ones is now unavoidable. In this research, we present cosmic-ray test results of a prototype RPC for the SHiP (search for hidden particles) experiment using 1.6- and 1.4-mm-thick RPC electrodes containing mixtures of various gases, including 1,3,3,3-tetrafluoropropene (HFO1234ze), CO₂, iC₄H₁₀ and SF₆. We compare the performance data gathered with these new gas mixtures with those gathered with a traditional TFE-based gas used for RPCs in compact muon solenoid (CMS) and a toroidal LHC apparatus (ATLAS) experiments. The addition of CO₂ to the HFO1234ze-based gas was found to be fairly effective in reducing the working-point high voltage (HVWP) for RPC operation. The results of our experiments lead us to the conclusion that adding 40% CO₂ or less, when combined with HFO1234ze-based gas, is conducive to reliable detector performance for SHiP single-gap phenolic RPCs.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2124-2129
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• 2007

A VCHP was fabricated and tested for its thermal performance. The container was made of copper, and the working fluid was water. STS-316 screen of mesh number 100 was inserted as a capillary structure. As a baseline performance, a normal heat pipe of the same dimensions was tested in advance to compare with VCHP, where an inert gas container was attached. The outer diameter of the heat pipe was 12.8 mm and the total length was 600 mm. The evaporator and the condenser lengths were both 200 mm. The thermal load ranged from 20 to 300W. Typical result revealed that the operating temperature of the VCHP stayed almost constant, while that of the normal heat pipe varied as much as 40$^{\circ}C$. Therefore, it was demonstrated that the VCHP is very effective for temperature control of heat-dissipating devices.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.181-184
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• 2002

The purpose of this study is to analysis the charging gas effect on the resonance and performance characteristics of the linear compressor for small scale FPFD Stirling refrigerator. To ensure high performance of FPFD type Stirling refrigerator, the operating frequency of the refrigerator should be around the natural frequency of compressor. The gas spring effect which is induced from pressure change in cylinder due to motion of pistons has significant effect on the natural frequency of the compressor. The numerical results show the linear compressor has high natural frequency when the charging pressure of working fluid is high.

• 한국진공학회지
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• 제15권1호
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• pp.14-23
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• 2006

스크롤 펌프는 초청정 진공 시스템에서 많이 사용되고 있지만 막상 수소 배기 특성에 대해서 잘 알려져 있지 않다 이런 정보부족은 수소를 다량 사용하는 핵융합 실험장치에서 스크롤 점프가 사용 가능한지 판단하기 어렵게 만든다 이 논문에서는 특히 수소에 대한 스크롤펌프의 배기속도, 압측비 및 역류특성을 측정하기 위해 구성한 실험장치, 측정절차와 실험결과에 대해 기술하고 논의했다.

• 태양에너지
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• 제12권1호
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• pp.95-102
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• 1992

후레넬렌즈(면적 $0.5m^2$)에 의해서 고밀도 집광능력을 갖는 소형태양 집열시스템이 태양에너지 집열장치와 소형 유동층 태양광 수열장치로서 개발되었다. 유동층 수열장치에서의 성능과 온도분포는 SiC 입자와 공기를 작동유체로 하여서 측정하였다. 본 연구에서는 공기 최대도달 온도는 1250K이었다. 또한 개발한 태양에너지 집열기와 유동층 수열장치에 대한 에너지 효율은 높았다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.336-336
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• 2010

Ga doped ZnO (GZO) transparent conductive films were deposited on the glass substrates at room temperature by facing target sputtering (FTS) method. The sputtering targets were 100 mm diameter disks of GZO($Ga_2O_3$ 3.w.t%) and Zn metal. The GZO thin films were deposited as a various $PO_2$ (oxygen gas content). Base pressure was $2{\times}10^{-6}$torr, and a working pressure was 1mTorr. The properties of thin films on the electrical and optical properties of the deposited films were investigated by using a four-point probe, a Hall Effect measurement and an UV/VIS spectrometer. The minimum resistivity of film was $6.5{\times}10^{-4}$[$\Omega$-cm] and the average transmittance of over 80% was seen in the visible range.

• 동력기계공학회지
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• 제5권2호
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• pp.57-62
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• 2001

Gas turbine performance is highly dependent on the engine performance which is closely related to the engine materials since they are exposed to severe working environments, i.e, high temperature and high stresses. For this reason, advanced materials with improved properties are required for the engine. The purpose of this research is to develop key materials technologies for aircraft industry and to tester domestic production of related parts. In this paper, the real-time prediction of high temperature creep strength and creep life for nickel-based superalloy Udimet 720(high-temperature and high-pressure the gas turbine engine materials) was performed on round-bar type specimens under pure load at the temperatures of 538, 649 and $704^{\circ}C$.

• 한국산업보건학회지
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• 제4권1호
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• pp.25-32
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• 1994

Arylmethyl halides(benzyl chloride, BZYC; benzal chloride, BZYA; benzotrichloride, BZTC) and related compounds(benzyl alcohol, BZYA; benzoyl chloride, BZOC) were determined by GC using capillary column. Detailed results are as follows. 1. Stability In methanol benzotrichloride slowly transferred to benzoyl chloride by hydrolysis(ca. 7.5% for 5 days), but the others were stable. Therefore, benzotrichloride solution should be prepared just before analysis. 2. GC analysis Tenax-GC was used to absorbent and desorption solvents were $CCl_4$ and MeOH. Arylmethyl halides were analyzed within 7.5min without interference with related compounds. The calibration curve(ca. 15-80 ppm in soln), repeatability(n=10) and the desorption efficiency were good. Limit of detection by NIOSH method was about 0.003 ppm for arylmethyl halide, respectively. To analyze arylmethyl halides and related compounds in working places GC using capillary column is anticipated to be used effectively.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.241-247
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• 2003

The sealing performance of O-ring is effected in environments of the O-ring seal, like that applied pressure, working temperature, pre-compressed ratio and materials. In this paper, design of composite O-ring under pressurized, compressed was optimized based on Taguchi experimental design method. and it analysed numerically using non-linear finite element method. Ogden model in which is developed based on the experimental data is used for simulating the contact stress and strain in NBR and PTFE materials. Sensitivity analysis was performed with FEM results, which are contact stress, strain and temperature as variable.

• 한국자동차공학회논문집
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• 제11권2호
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• pp.111-118
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• 2003

Recently, environmental damage to urban area becomes serious problem due to the exhaust emissions by increasing the number of vehicle. Especially, exhaust emission from diesel vehicles are blown to be harmful to human health and environment. Photoacoustic Spectroscopy system is very useful technology for simultaneous and continuous measurement of the various components of the automotive exhaust gas. In this study, in order to reduce emission gases from automobile, we tried to develop the measurement system of Photoacoustic Spectroscopy. To improve performance of high sensitive Photoacoustic Spectroscopy system for automotive exhaust emissions, the shape of Photoacoustic Spectroscopy cell was optimized to use the flow analysis. And Exhaust emission data of the 1,500cc gasoline engine was fixed the working fluid. The characteristics of fluid flow for cell were analyzed by various conditions in detail.