• Journal of Mechanical Science and Technology
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• v.18 no.8
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• pp.1338-1348
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• 2004

A simplified method that models the deflagration process occurring in closed or vented vessels is described. When combustion occurs within the spherical or cylindrical vessels, the flame moves spherically or segmentally to the vessel periphery. The volume and area of each element along the propagating flame front are calculated by using simple geometrical rules. For instabilities and turbulence resulting in enhanced burning rates, a simple analysis results in reasonable agreement with the experimental pressure transients when two burning rates (a laminar burning rate prior to the onset of instability and an enhanced burning rate) were used. Pressure reduction caused by a vent opening at predetermined pressure was modeled. Parameters examined in the modeling include ignition location, mixture concentration, vented area, and vent opening pressure. It was found that venting was effective in reducing the peak pressure experienced in vessels. The model can be expected to estimate reasonable peak pressures and flame front distances by modeling the enhanced burning rates, that is, turbulent enhancement factor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1104-1108
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• 2007

Automobile sunroof buffeting is the tonal noise of low frequency around 20Hz. It occurs due to the acoustic feedback process between the shear layer detached from the leading edge of sunroof opening and the Helmholtz resonator-like property of a car cabin. In this paper, PIV visualization technique is applied to the unsteady flow field around sunroof opening of an SUV in the full-scale automotive wind tunnel in order to find out buffeting mechanism. A phase-marking PIV measurement method, in which image and sound pressure are recorded simultaneously, and a phase-rearrangement post-processing program were developed for capturing noise-related velocity fields without expensive synchronization systems. Through this study, some characteristics of the real-car sunroof shear layers under various deflector conditions were identified and these results can provide insights into the noise reduction mechanism of the tube-type deflector.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.23-28
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• 1996

The potential for the RELAP5/MOD3.2 was assessed for the loss-of-RHR event during the mid-loop operation and the predictability of major thermal-hydraulic phenomena was also evaluated for the long term transient. The analysis results of the typical two cases(cold leg opening case and pressurizer opening case) were compared with experimental data which was conducted at ROSA-IV/LSTF in Japan. As a result, it was shown that tile code was capable of simulating the thermal-hydraulic transport process with appropriate time step during the reduced inventory operation with the loss-of- RHR system.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.102-105
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• 2006

Nowadays, increase of demands on efficient utilization of resources while construction process stimulates structural engineers to select remodeling to improve old buildings. To analyze the effects of openings that may be installed in the course of remodeling old buildings, an experimental research was carried out using four approximately half scale of specimens subjected to constant axial forces, and cyclic loading to simulate seismic conditions. Consequently, the existence of opening was verified to induce different observed damages, which caused by reduction of compression strut support formed on the surface of wall. Especially, the maximum force was revealed to decrease approximately 35% as openings were existed. As this tendency was appeared with stiffness and energy dissipation capacity.

• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.161-170
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• 1994

For the preparation of short ceramic fibers of which average length might be in accordance with the opening size of sieve, e.g., 150${\mu}{\textrm}{m}$ or 300${\mu}{\textrm}{m}$, bulk fibers were grounded on sieve screen by applying both compressing and shearing force, and passed through the sieve screen. The grounded fibers were subjected to gravitational settling processes. The classified fibers were observed by scanning electron microscopy and the length of each fiber was measured to correlate the average length with the opening size of the sieve used for grinding bulk fibers. Theoretical analysis show that a free settling technique is ineffective for the classification of fibers by length compared with that of particles. The average lengths of classified fibers estimated by scanning electron microscopy were in good agreement with those obtained by relative packing volume of the fibers. Accordingly, it is confirmed that average fiber lengths can be determined from bulk volume data without photographing, counting and averaging results for hundreds of fibers.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.2
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• pp.260-271
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• 2003

For the Purpose of understanding the mixing phenomena of a GDI(Gasoline Direct Injection) engine, the spray behaviors and fuel distributions were investigated in a single cylinder transparent GDI engine. The experimental engine is a swirl type GDI engine with a SCV(Swirl Control Valve). PLIF(Planar Laser Induced Fluorescence) system with KrF Excimer laser was used for the measurement of the fuel distributions. The effects of SCV opening angles and the injector specifications on the fuel distribution characteristics were investigated. As a result, it was found that the SCV opening angle had a great effect on the fuel distributions in the late stage of compression process by changing the flow fields in the combustion chamber.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.49-59
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• 2002

For the purpose of helping development of a GDI(Gasoline Direct Injection) engine, the spray behaviors and fuel distributions were investigated in a single cylinder GDI engine. The experimental engine is a swirl type GBI engine with a SCV(Swirl Control Valve). PLIF(Planar Laser Induced Fluorescence) system with KrF Excimer laser was used for the measurement of the fuel distributions. The effects of SCV opening angle and the Injector specifications, such as the spray cone angle and the offset an91e on the fuel distributions characteristics were investigated. As a result, it was found that the SCV opening angle had a great effect on the fuel distributions in the late stage of compression process by changing flow fields in the combustion chamber.

• Journal of the Korean Society of Costume
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• v.50 no.8
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• pp.149-163
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• 2000

The purpose of this study is to research the Korean and Japanese costume systems and to compare both of them on the process of adopting the western-originated costumes. The consequences of this study are as follows. Chosen and Japan started simplifying the traditional clothings, Introducing the western clothings and executed the ordinance prohibitory topknots through reforming costume systems since Port Opening Treaties in 19th centra. Japan performed the reformation of costume system effectively through the grand campaign of social reforming enlightment by Meiji Government. Meanwhile in Korea, there were a continual repetition of adoption and rejection in the reformation of costume systems because of strong cultural self-esteem and competition of foreign Empires. However, western-originated cultural perspectives brought the strong self-devaluated view on their own cultures to both countries. And that's the first cause of substitution of western clothings for ordinary ones in both nations.

• Bulletin of the Korean Chemical Society
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• v.28 no.9
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• pp.1553-1561
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• 2007

The new type of heterometallic chiral polymer salen complexes have been synthesized and it has been found that group 13 metal salts (AlCl3, GaCl3 and InCl3) combined to cobalt salen unit played the crucial role in the asymmetric kinetic resolution of racemic epoxides. Polymeric salen catalysts showed very high reactivity and enantioselectivity for the asymmetric ring opening of terminal epoxide with diverse nucleophiles. They provide the enantiopure useful chiral intermediates such as chiral terminal epoxides and α -aryloxy alcohols in one-step process. An efficient methodology for providing very high enantioselectivity can be achieved in the synthesis of valuable chiral building blocks via our catalytic system by combination of various asymmetric ring opening reactions.

• Journal of Plant Biology
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• v.27 no.3
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• pp.107-127
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• 1984

An anthecological study of Tilia in Korea was undertaken for six native and one introduced species. Flowers are protoandrous with anther and stigma opening during the day-time in section(sect) Anastraea and the night-time in sect Astrophilyra. Nectar production was coincided with anther and stigma opening. It is revealed that the primary role of floral bracts was attracting pollinators especially in sect Astrophilyra. The peak of stamen and stigma function, and the production of nectar and odor were closely related with pollinator attraction. Forthy-three species of insects in 30 families were identified for the pollination studies; bees were the most commonly observed visitors in sect Anastraea, while moths were the primary visitors in sect Astrophilyra. Pollination study indicate that it is section specific. But within a section, pollination is not species specific thus interspecific hybridization occurs.