• Journal of the Korean Vacuum Society
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• v.6 no.3
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• pp.187-193
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• 1997

We investigated the initial growth mode of Cu deposited on polyimide at room temperature using x-ray photoelectron spectroscopy. We could find that when Cu is sputter-deposited on the polymide, Cu-N-O complex of strong interaction is mainly formed first, Cu-oxide of weak interaction is formed successively, and then finally metallic Cu grow. From these results, we could conclude that Cu/polyimide interface consists of Cu-N-O complex and Cu-oxide.

• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.70-78
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• 1997

The objective of this research is to study on the upper and lower layer temperature, interface height and pressure in case of carpet, chair, trashcan and wardrobe fires in a residential room by performing the theoretical and experimental studies. The theoretical results of the upper and lower layer temperature, the interface height and the pressure were qualitatively well coincided with the experimental results. The uniformly distributed fire in case of carpet showed that the ignition and the initial growth period were relatively short while the fully developed period was considerably long. The concentrated fires such as the wardrobe showed that the ignitions and the initial growth periods were relatively long. The interface heights were around 1m as the steady state. However, at the time of the maximum temperature, the interface height was lowered to 0.5m from the floor. The pressure variation in the fire room ranged between 0.1mmAq and 0.4mmAq, and the temperature reached the highest while the pressure was maximum.

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.94-100
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• 1997

The objective of this research is to study the formations of smoke layer in case of several furniture fires such as trashcan, carpet, mattress and wardrobe as a fire starter in a residential room by performing the experimental studies. The uniformly distributed fire in case of carpet showed that the ignition and the initial growth period were relatively short while the fully developed period was considerably long. The concentrated fires such as the trashcan, mattress and wardrobe showed that the ignitions and the initial growth periods were relatively long. The descending speed of the interface height was proportioned to the inflammability of the furniture and the spread of the fire. The time required to come down around 1m was within 1-3 minutes. The Interface heights for the furniture fires were around 1m as the steady state. However, at the time of the maximum temperature, the interface height was lowered to 0.25m-0.75m from the floor. The carbon dioxide concentration reached the highest while the oxygen concentration was minimum.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.6
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• pp.792-801
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• 2000

The problem of phase change from liquid to solid in the inviscid plane-stagnation flow is theoretically investigated. The solution at the initial stage of freezing is obtained by expanding it in powers of time, and the final equilibrium state is determined from the steady-state governing equations. The transient solution is dependent on the three dimensionless parameters, but the equilibrium state is determined by one parameter of (temperature ratio/conductivity ratio). The effect of the fluid flow on the growth rate of the solid in the pure conduction problem can be clearly seen from the solution of the initial stage and the final equilibrium state. The characteristics of the transient heat transfer at the surface of the solid and the liquid side of the solid-liquid interface for all the dimensionless parameters are elucidated.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.106-112
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• 1999

It is very important to have exact informations on the properties and characteristics of the sintered steel as a new material of machine elements. The bending fatigue tests are performed for the sintered steel bend specimens of various densities 6.6 to 7.0 g/$cm^3$ and the sintered spur gear to consisted of Fe-Cu-C. The fatigue test at a constant stress amplitude is performed by using an electrohydraulic servo-controlled pulsating tester. Consequently, the S-N curves are obtained. The fatigue strength S for fatigue life N of the specimen with the initial length of crack ai is simulated, and they are shown as N-S-A curves. This study investigate the crack growth characteristics by experiments and present crack growth simulation method for sintered gear

• The Korean Journal of Food And Nutrition
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• v.5 no.2
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• pp.77-83
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• 1992

The optimum conditions and mechanisms for the plasmid-mediated genetic transformation of intact cells of Bacillus brevis Pl76-2, an extracellular protein producing bacterium by electroporation were investigated. It was found that pUB110 Plasmid DNA can be introduced into intact bacterial cells by electroporation. The frequency of transformation by this electroporation system depended upon the initial electric field strength, the capacity of the electric discharge capacitor, growth stage, number of successive pulses and composition of electroporation buffer. It was effective for transformation that cells were harvested, washed and resuspended with HSM [7M HEPES(PH 7.4), 272mM sucrose, 1 mM MgCl2] electroporation buffer when cell growth was attained to 1.2 at OD660. A maximum frequency of transformation of 2.40$\times$104 transformants per$\mu$g plasmid DNA was obtained by two succesive Pulses with an initial electric field strength of 12.5kV/cm and with a capacitance of 7.3uF.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.24-33
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• 1999

This paper investigate the effects of the variations of engine operation condition in the flame kernel formation and developmnet . A model for calculating the initial kernel development in spark ignition engines is formualted. It considered input of electrical energy, combustion energy release and heat transfer to the spark plyg, cylinder head, and unburned mixture. The model also takes into accounts strain rate of initial kernel and residual gas fraction. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy and turbulent flame expansion. Flame kernel development also influenced by engine operating conditions, for example, EGR rate, air-fuel ration and intake manifold pressure.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.6
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• pp.752-758
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• 2005

This study examined growth and sensory characteristics of soybean sprout cultured at $25\pm1^{\circ}C$ for 4 days with distilled water(control) and green tea extract(0.03 and $0.05\%$). Initial germination rate was higher when soaking in green-tea extract than in the control. The proper concentration of green-tea extract was $0.03\%$. The growth of soybean sprout in $0.05\%$ green-tea extract was better than the control for the hypocotyl thickness and mot hair. Soybean sprout grown with green-tea extract were better than that with control inappearance, flavor, texture and over-all acceptabilitty.

• Journal of the Korean Society of Safety
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• v.29 no.3
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• pp.136-142
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• 2014

Recently a new version of PRO-LOCA program was released. Using the program, failure probability of pipes can be evaluated considering fatigue and/or stress corrosion crack growth and the effects of various parameters on the integrity of pipes in nuclear power plants can be evaluated quantitatively. The analysis results can be used to establish an inspection plan and to examine the effects of important parameters in a maintenance plan. In this study, sensitivity analyses were performed using the program for several important parameters including sampling method, initial crack size, number of initial fabrication flaws, operation temperature, inspection interval, operation temperature and nominal applied bending stress. The effect of parameters on the leak and rupture probability of pipes was evaluated due to fatigue or stress corrosion crack growth.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.177-182
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• 1996

The objective of this thesis is to investigate the influence of welding residual stresses on the fatigue growth behavior of welding residual stresses on the fatigue growth behavior of cracks located transverse to the weld bead. For this purpose, G.T.A. (Gas Tungsten Arc) welding was performed on the Al. Alloy 1100-0 plate and the same initial crack is made on HAZ(Heat Affected Zone), weld metal and base metal respectively. C.T.(Compact Tension) specimens were used as experimental material. Initial welding residual stresses were measured by using strain gage sectioning method. All specimens were tested under constant amplitude load with stress ratio R=0.1