• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.47-53
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• 2004

미국, 일본 및 유럽을 중심으로 오랫동안 검토가 진행되어 왔던 HDTV(High Definition TV)가 2005년을 본격적인 상용화의 원년으로 하여 각국에서 많은 활동이 이루어지고 있다. HDTV 보급에 있어서, 핵심적인 부문을 차지하고 있는 Display는 지난 백 여년간 그 명맥을 유지하여 오던 CRT(Cathode Ray Tube)가 Display의 Size 및 해상도면에서 그 한계를 드러냄에 따라 그 퇴조를 선언하고, 대체 Device의 출현을 기대하고 있다. 특히 기술 개발의 중심이 되고 있는 플라즈마 디스플레이(PDP, Plasma Display) 및 LCD(Liquid Crystal Display)는 평판 디스플레이로서의 장점으로 차별화 되어 그 발전가능성에 많은 관심을 받고 있으며, 그로 인한 약진이 두각을 나타내고 있다. (중략)

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.129-133
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• 2000

The purpose of this paper is to develope concrete which presents self-damage as soon as the crack by external force occur. In experiment, when concrete specimens inserted glass filled with mixed liquid into were loaded, glass tube was break and crack around became red color. Failure properties were investigated according to type, location of sensor and existence of reinforced bar.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.208-209
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• 2000

기존의 CRT(cathode-ray tube)를 사용한 TV, 모니터와 같은 디스플레이는 부피가 커서 공간을 많이 차지하고 휴대품으로는 거의 사용이 불가능하였다. 그러나, 평판 디스플레이의 하나인 LCD(liquid crystal display)는 소비 전력이 작고 부피가 작아서 게임기, Note-book PC와 같은 휴대용으로는 물론 PC용 모니터와 같은 사무용 디스플레이, TV와 같은 가정용 디스플레이를 대체해 나가고 있다. (중략)

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.558-563
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• 1997

A thermal sizing code, named as HSGSA (Helical coil Steam Generator Sizing Analyzer), for a sodium heated helical coil steam generator is developed for KALIMER (Korea Advanced LIquid MEtal Reactor) design. The theoretical modeling of the shell and tube sides is described and relevant correlations are presented. For assessment of HSGSA, a reference plant design case is compared to the calculational outputs from HSGSA simulation.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.25-25
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• 2003

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.129-132
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• 2008

Combustion characteristics of a gas generator for a 30 ton-class liquid rocket engine were studied. At the early stage of development, the combustion tests of the gas generator were performed by only using the nozzle which substitute for a turbine manifold exit. Then, the extension tube was applied between the gas generator and the nozzle for imitating the resonant mode of gas generator and turbine manifold. Finally, the hot-firing tests were performed on the condition of connecting the gas generator with the turbine manifold. In the paper, the step-by-step results such as temperature distribution and pressure fluctuations were analyzed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.4
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• pp.499-509
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• 1998

In the absorption process of water vapor in a liquid film, the composition of the gas phase, in which a non-absorbable gas is combined with the absorbate influences the transport characteristics remarkably. In the present study, the absorption processes of water vapor into aqueous solution of lithium bromide in the presence of non-absorbable gases were investigated analytically. The continuity, momentum, energy and diffusion equations for the solution film and gas phase were formulated in integral forms and solved numerically. It was found that the mass transfer resistance in gas phase increased with the concentration of non-absorbable gas. However the primary resistance to mass transfer was in the liquid phase. As the concentration of non-absorbable gas in the absorbate increased, the liquid-vapor interfacial temperature and concentration of absorbate in solution decreased, which resulted in the reduction of absorption rate. The reduction of mass transfer rate was found to be significant for the addition of a small amount of non-absorbable gas to the pure vapor, especially at the outlet of an absorber where non-absorbable gases accumulated. At higher non-absorbable gas concentration, the decrease of absorption flux was almost linear to the volumetric concentration of non-absorbable gas.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.82-89
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• 2016

The unique phenomenon that jet flow kinetic energy is converted to thermal energy through thermoacoustic resonance can be applied for the multiple ignition of liquid rocket engines. The present article includes the basic principle and theory behind the phenomenon as well as major outstanding, previous research works. The thermoacoustic phenomenon is affected by underexpanded jet flow characteristics from a nozzle, geometries of a nozzle and a resonance tube, and chemical composition of jet flow. The paper concludes with discussion what should be considered as crucial issues for the future research on the development of a multiple ignition system of liquid rocket engines.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.2
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• pp.164-170
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• 1992

In order to understand and explain the spary combustion, it was necessary to understand the disintegration mechanisms of liquid jet. To understand the disintegration mechanisms of liquid jet, the disintegration phenomena and uniform droplet production regions of testing liquid jet was investigated by means of longitudinally vibration capillary nozzle, which was injected the testing liquids. The testing liquids were light oil and light oil and light oil blended with 25wt% fish oil (File fish oil, Sardine fish oil, Alaska pollac oil) The results can be summarized as follows: 1. The uniform droplet phenomena have been changed according to the frequency of capillary tube, the jet velocity and physical properties of testing oils. 2. Within the region of uniform droplet, Reynold number was increased as Weber number increases. 3. The lower limit of wave length in which uniform droplet was produced 0.8d which was lower than Rayleigh wave length 4. The light oil blended with file fish oil which has lower viscosity and surface tension had the widest uniform droplet production region on the frequency and velocity among testing oils. But light oil blended with sardine fish oil were similar with light oil in the uniform production region.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.4
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• pp.247-251
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• 2017

Titanium alloy has been widely used in the aerospace industry because of its high strength and good corrosion resistance. During cutting, the low thermal conductivity and high chemical reactivity of titanium generate a high cutting temperature and accelerates tool wear. To improve cutting tool life, cryogenic machining by using a liquid nitrogen (LN2) jet is suggested. In cryogenic jet cooling, evaporation of LN2 in the tank and transfer tube could cause pressure fluctuation and change the cooling rate. In this work, cooling uniformity is investigated in terms of liquid nitrogen jet pressure in cryogenic jet cooling during titanium alloy turning. Fluctuation of jet spraying pressure causes tool temperature to fluctuate. It is possible to suppress the fluctuation of the jet pressure and improve cooling by using a phase separator. Measuring tool temperature shows that consistent LN2 jet pressure improves cryogenic cooling uniformity.