• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.132-137
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• 2006

With the help of the development of digital-multimedia in the middle of 1990's, FDP(Flat Panel Display) had attracted considerable attention. Collimation proximity exposure system that transfers the pattern on wafer or glass exactly using mask and light with appropriate wavelength is core process in semiconductor and liquid display element. The performances of resolution required in precision exposure system are evaluated by resolving power, depth of focus and storage area. Most of development has targeted on these three factors. The optical design including lamp house has played an important role on the performance of exposure process. In this study, we evaluate the cooling system, concerning on exposure device with mercury lamp among the kernel equipment for the production of LCD, to prevent the instability of lighting due to long term accumulation of excessive heating inside the lamp house. Numerical analysis is conducted on full-scale model. The characteristics of three-dimensional flow, pressure and temperature distribution on exposure system are graphically depicted to estimate the whole cooling system for lamp house and to establish the design criteria.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.7
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• pp.275-282
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• 2016

MILD (Moderate and Intense Low-oxygen Dilution) combustion using oxygen as an oxidizer is considered as one of the most promising combustion technologies for high energy efficiency and for reducing nitrogen oxide and carbon dioxide emissions. In order to investigate the effects of nozzle angle and oxygen velocity conditions on the formation of oxygen-MILD combustion, numerical and experimental approaches were performed in this study. The numerical results showed that the recirculation ratio ($K_V$), which is an important parameter for performing MILD combustion, was increased in the main reaction zone when the nozzle angle was changed from 0 degrees to 15 degrees. Also, it was observed that a low and uniform temperature distribution was achieved at an oxygen velocity of 400 m/s. The perfectly invisible oxy-MILD flame was observed experimentally under the condition of a nozzle angle of $10^{\circ}$ and an oxygen velocity of 400 m/s. Moreover, the NOx emission limit was satisfied with NOx regulation of less than 80 ppm.

• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.27-34
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• 2008

The temperature distribution in the weldment is not uniform because a weldment is locally heated. Thermal plastic deformation results from the local expansion and shrinkage by the heating and cooling of metal. Therefore, residual stresses and distortion occur in the weldment. In this study, we had conducted on the weld thermal cycle simulation that is supposed as the HAZ on SS400 steel and STS304 steel. The residual stresses that were obtained from the drawing and the weld thermal cycle simulation were estimated by X-ray diffraction. We also carried out ultrasonic test for the weld thermal cycle simulated specimens, and then conducted on nondestructive evaluation by the ultrasonic parameters obtained ultrasonic test. From the results, residual stresses of weld thermal cycle simulated specimens after the residual stress removal heat treatment are lower than that of the drawing.

• Textile Coloration and Finishing
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• v.28 no.3
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• pp.164-174
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• 2016

In this study, dye-encapsulated microcapsules were produced by emulsion polymerization using styrene monomer. The study showed that the average size of microcapsules were $2{\sim}5{\mu}m$ in normal distribution. These microcapsules induced pale yellow(A12) and reddish yellow(B24) color by thermochromic fluoran yellow(dye A) and red(dye B). These microcapsules were changed to dark yellow(A12) and scarlet(B24) color depending on temperature change. The weight of microcapsules decreased by 7% to 11% during the heating ranges from $320^{\circ}C$ to $350^{\circ}C$ implying that the styrene microcapsules had thermal stability upto $300^{\circ}C$.

• Transactions of Materials Processing
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• v.22 no.4
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• pp.189-195
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• 2013

In this study, the weld strength of extru-rivet spot welding was investigated by simulation and experiment. In order to obtain hot plasticity flow bonding of the two plates by a single rivet, electrodes are used for heating of the two plates and the rivet by electric resistance. Because weld strength is influenced by the temperature in the weld zone, the diameter of the electrodes and the amount of current supplied to the electrodes are important variables. For the simulation, heat distribution and weld strength were calculated using DEFORM-3D. The weld strength in the weld zone was calculated for various values of the experimental parameters. The simulation results showed that the weld strength was the highest when the weld current was 37kA, the electrode diameter was 12mm, and the welding frequency was 90cycle. Aluminum 5052 was used for the experimental study. A total of three aluminum plates, two welding plates with 1mm thickness and one plate with 2mm thickness for the inserting rivet, were used for the experimental extru-rivet spot welding.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.369-376
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• 1996

Major atmospheric stability classification methods were evaluated with meteorological data obtained by scoustic sounding profiler (SODAR/RASS) in Seoul. The Psequill classificatio method, the method most widely used because of its good agreement in respect of synoptic scope under the steady state, fails to describe the time lag, the response time on stability by heating or cooling caused by daily insolation or noctrunal surface radiation. Horizontal and vertical standard deviation of wind fluctuation $(\sigma_A and \sigma_E)$ method tend to classify night-time stable condition (E, F class) into unstable condition (A, B class). The classification matrix tables for Vogt's vertical temperature difference and wind speed using method ($\Delta$T $\cdot$ U) and bulk Richardson number (Rb) were amended for practical use over Seoul. The modified tables for $\Delta$T $\cdot$ U and Rb method were made by using comprehensive frequency distribution from Pasquill's method and other existing results, and the correlation coefficient(r) was equal to 0.829. It was confirmed that atmospheric stability could be changed with monitoring site characteristics, height and vertical difference between sensors of monitoring station, and classification method itself.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.270-277
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• 2011

Laser cartilage reshaping(LCR) is a promising method for reshaping cartilage by using laser irradiation to maintain permanently modifies its shape. However this method has not been fully understood due to the limited scientific researches. The purpose of this study is to analyze optical and thermal characteristics of cartilage during laser irradiation. After analyzing Monte Carlo simulation for the comparison of laser fluence distributions with different laser wavelengths the characterization of the spectral changes during Nd:YAG laser(${\lambda}$ = 1444 nm) irradiation was investigated in the ranges of 900-1700 nm with double integrating spheres. The surface temperature distribution changes during laser irradiation were investigated with an infrared camera. The quantitative measurements of optical and thermal characteristics in cartilage after laser irradiation were correlated with the transition of water flux(from bound to free water) and this study may be useful for better understanding of biophysical transformation phenomena in cartilage after laser heating.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.647-650
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• 2017

As the necessity of development of supersonic vehicle increases, securing an aerodynamic data from low to high altitude is requested for flying vehicles crusing in various high-tech environment. Therefore our research team built equipment by improving heating device of Model Aerodynamic Facility(MAF) of Konkuk University to simualte a real gas environment. Guided weapon system and temperature and velocity distribution according to the flow that is produced from the pier of supersonic vehicle is planned to be researched by using this equipment.

• Journal of Welding and Joining
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• v.5 no.3
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• pp.46-52
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• 1987

The mechanism of transverse shrinkage for the butt joint weldig of plates is investigated in this paper. It was certified that the compressive plastic strain due to thermal expansion of materials during heating play an important role on the transverse shrinkage. It was also pointed out that the transverse shrinkage has to be treated with the samples of which the shapes are as close to real shapes of welded materials as possible, because the distribution of temperature and relative rigidity of materials during welding have great influence on the transverse shrinkage. The formulas for the calculation of transverse shrinkage were presented and the experiments were carried out in order to verify the formulas. the main results are as follows; 1. For the bead-on-plate welding, the transverse shrinkage in the begining parts of welding is the smallest, the end parts is next and the transverse shrinkage of mid section is the largest. 2. In bead-on-plate welding, the equations presented in this paper concerning transverse shrinkage coincide fairly well with the experimental values generally. 3. Transverse shrinkage increases generally as specific heat input per unit thickness increaes.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.645-650
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• 2006

The heat transfer performance and energy transport ability are relatively high due to higher specific heat. Therefore, it can be used in fields such as heating, ventilating, air-conditioning, refrigeration and heat exchangers. In this study, liquid-cooling heat exchangers were designed and tested by varying geometry and operating conditions. In addition, liquid-cooling heat exchangers were tested to provide performance data for MPCM slurry. The liquid-cooling heat exchangers had twelve rectangular channels with flow paths of 1, 2, 4 and 12. Silicon rubber heaters were used to control the heat load to the heat exchanger. Heat input ranged from 293 to 800 W, and inlet temperatures of working fluid varied from 15S to $27^{\circ}C$. The standard deviation of surface temperature was strongly affected by the coolant of MPCM Slurry, All MPCM-cooling heat exchangers showed higher cooling performance than the water-cooling heat exchanger except one path channel heat exchanger.