• Journal of the Korean Society of Combustion
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• v.12 no.1
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• pp.21-27
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• 2007

The supersonic combustion experiments are carried out using T3 free-piston shock tunnel. Different shock tube fill pressures have various inflow conditions. $15^{\circ}$ inclined hydrogen fuel injection is located before the cavity. Oblique shock is generated at the trailing edge of the cavity and reflects off the top and bottom wall. For non-reacting flow, static pressures in low equivalence ratio are similar to those in no fuel injection. As equivalence ratio is increased, static pressures are increased in the duct. In the similar equivalence ratio, static pressures are increased when total enthalpy is decreased. For reacting flow, the flame is occurred near the cavity. The combustion is weak locally in the middle of the duct. The up and down pressure distribution in the duct means that the supersonic combustion is generated.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.212-219
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• 1993

To reduce the mode noise induced from a multimode dye laser, a modeless laser generating amplified spontaneous emission was used as Stokes beam of the broadband CARS. A new technique for measuring species concentration from the modulation dip of nonresonant background of broadband CARS spectrum was proposed. The modulation dip was numerically calculated and fitted as a function of the concentration of the minor species and temperature of gas sample. We applied this technique in measuring CO concentration in a static cell and also the profile of CO concentration in a CHdair premixed flame of a counterflow burner.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.328-331
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• 2008

In order to see the detailed characteristics of model scramjet engine, numerical analysis was performed and compared to the ground test results done by KARI and UQ. Pressure distribution predicted by numerical analysis showed good agreements with test results. Static temperature and pressure distribution explained the mechanisms of cavity flame holder and W-shape cowl which have showed enhancing effects on the supersonic combustion.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.65-71
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• 1999

An experimental study was carried out in order to investigate the effect of shock waves on the supersonic hydrogen-air jet flames stabilized in the Mach 2.5 model scramjet combustor. This experiment was the first reacting flow experiment interacting with shock waves. Two identical $10^{\cire}$ wedges were mounted on the diverging sidewalls of the combustor in order to produce oblique shock waves that interacted with the flame. Schlieren visualization pictures, wall static pressures, and combustion efficiency at two different air stagnation temperatures were measured and compared to corresponding flames without shock wave-flame interaction. It was observed that shock waves significantly altered the shape of supersonic jet flames, but had different effects on combustion efficiency depending on air temperatures. At the higher air stagnation temperature and higher fuel flow rates, combustion of efficiency showed a better result.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.76-87
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• 2019

A direct connected test was conducted for a supersonic combustor with a cavity-type flame holder. Liquid hydro-carbon fuel was injected in different types of injectors: inclined and aeroramp injectors, for the flow condition of Mach 4 at an altitude of 20 km. The static pressure on the combustor wall along the axis and the total pressure at the exit of combustor were measured to analyze the combustion characteristics at various fuel flow rates.

• Journal of Powder Materials
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• v.28 no.5
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• pp.396-402
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• 2021

Stainless steel, a type of steel used for high-temperature parts, may cause damage when exposed to high temperatures, requiring additional coatings. In particular, the Cr₂O₃ product layer is unstable at 1000℃ and higher temperatures; therefore, it is necessary to improve the oxidation resistance. In this study, an aluminide (Fe₂Al₅ and FeAl₃) coating layer was formed on the surface of STS 630 specimens through Al diffusion coatings from 500℃ to 700℃ for up to 25 h. Because the coating layers of Fe₂Al₅ and FeAl₃ could not withstand temperatures above 1200℃, an Al₂O₃ coating layer is deposited on the surface through static oxidation treatment at 500℃ for 10 h. To confirm the ablation resistance of the resulting coating layer, dynamic flame exposure tests were conducted at 1350℃ for 5-15 min. Excellent oxidation resistance is observed in the coated base material beneath the aluminide layer. The conditions of the flame tests and coating are discussed in terms of microstructural variations.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.456-460
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• 2005

To enforce the maximum residue limit for residual hexane (0.005 g/kg) in commercially available Korean vegetable oil, convenient and accurate quantification methods were investigated. Using dual surrogate standards, pentane and heptane were dissolved in ethanol, and then added to hexane-tree sunflower oil for setting up the calibration curve. Gas Chromatograph-Flame Ionization Detector with a porous layer open tubular column, indicated good chromatographic separation of hexane from other inhibiting matrix components. The lowest calibration level was $0.5\;{\mu}g/g$, not exceeding a relative standard deviation of 10% (RSD%), and 1.0\;{\mu}g/g$ not exceeding a deviation of 22% RSD% using heptane as an internal standard for the Static headspace analysis by using a headspace auto-sampler and manual injection, respectively. The residual hexane was detected in nine of the samples among 87 vegetable oil samples purchased on the local market.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.1011-1016
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• 2009

In this paper, we propose the method of fire detection. A wide distribution of CCTV cameras (Closed Circuit Television) in many public areas can be used not only for video surveillance systems but also for detecting fire occurrence. A proposed approach is based on visual information through a static camera. Video sequences are analyzed to find fire candidates and then spatial analyses procedure for detected fire-like color foreground is carried out. From the simulation results, our method showed the best performance when spatial and temporal fire candidates changes rapidly and close to fire motion.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.247-248
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• 2012

Unidentified self-ignitions were reported when the high-pressure hydrogen gas suddenly leaked out. This paper presents a flow visualization study to investigate the self-ignition mechanism in a test tube how the ignition process is initiated and the flame propagates with measurement of a number of pressure and light sensors installed in the tube supported the analysis of the self-ignition. The test result showed the location of the self-ignition taken place and critical static pressure at the boundary layer for self-ignition.

• Bulletin of the Society of Naval Architects of Korea
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• v.12 no.2
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• pp.13-34
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• 1975

Analytical solutions for the transient temperature distribution and quasi-static thermal stresses which arise in a thin circular disk of finite radius subjected to an instantaneous point source acting in its interior have been obtained. And the solutions have been extended to the case of a moving heat source with the aid of the Duhamel's superposition integral. The solutions given are in the form of double infinite serieses, and their numerical results have been compared with the experimental temperature histories. It can be found out that the theoretical histories of thermal stresses show a good agreement with the experimental results and the theoretical histories of thermal stresses show a good qualitative agreement with a physical phenomena. The solutions can be applied to the problems such as a flame hardening of the cylindrical machine elements and a circular patch welding or a circular cutting of the structural member.