• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.426-430
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• 2010

There is fire dangers inside engine bay where fuel of oil leakge can be ignited by hot engine surfaces. So, Fire suppressor is needed to extinguish the flames. The current FAA requirement is that the concentration level should be greater than 6% by volume throughtout the protected zone for longer than a half second simultaneously. To Satisfy the FAA requirement, The Fire extinguish system should quickly delivery the fire extinguish agents and Fire extinguish system should be designed effectively. This study is to develop and simulate the injection of fire extinguish agents into the engine-bay. Transient simulations were performed and predicted the concentration of fire extinguish agents at the certain locatioin in the engine-bay.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.17-26
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• 2005

Dissimilar-metal welds(DHWs) are used widely in various industrial applications due to the pratical importance from the technical and economic aspect. However, DMWs have several fabricative and metallurgical drawbacks that can often lead to in-service failures. For example, the most pronounced fabrication faults are hot cracks. Recently, DMWs have used the various of heat source to decrease such as faults. In this paper, the weldability on dissimilar metal welds of Austenite stainless steel and Low carbon steel using a continuous wave Nd:YAG laser was experimentally investigated. Experiments were conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser.

• International Journal of High-Rise Buildings
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• v.5 no.4
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• pp.327-338
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• 2016

This technical paper presents a detailed review of the stack effect phenomenon and of the associated implications pertaining to the design and construction of high-rise buildings in regions of extreme climatic conditions. The present review is focused on both the classical 'chimney' effect as well as on the reverse stack effect, which are respectively related to cold and hot climates. For the purposed of the work here presented, the ASHRAE (2013) design conditions of Astana (Kazakhstan) and Riyadh (Kingdom of Saudi Arabia) were selected. A 230 m tall residential building of rectangular floor plan was numerically modelled in the context of the climatic conditions of the two abovementioned cities and a number of sensitivity analyses were performed, covering parametric changes of: temperature, façade air tightness, site wind speeds and wind directions.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.1
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• pp.143-153
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• 2004

Antimicrobial activities against Streptococcus mutans, Candida albicans, Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus were assayed through the hot water extracts and the ethanol extracts from Chungyulsodokeum and its composition oriental medicines. The stains were incubated on culture medium and activated. We observed the size of inhibition zone on the strains that is incubated in strilized filter paper disc with various concentration extracts of Chungyulsodokeum and its composition 1. The extracts of Chungyulsodokeum, Coptidis Rhizoma, Paeoniae Radix, Glycyrrhizae Radix, Gardeniae Fructus showed antimicrobial activities against Staphylococcus aureus. 2. The extracts of Chungyulsodokeum, Coptidis Rhizoma, Paeoniae Radix, Forsythiae Fructus Ghycyrrhizae Radix, showed antimiaobial activities against Staphylococcus epidermidis. 3. The extracts of Chungyulsodokeum, Coptidis Rhizoma, Paeoniae Radix, Glycyrrhizae Radix, showed antimicrobial activities against Streptococcus mutans. 4. The extract of Coptidis Rhizoma showed antimicrobial activities against Candida albicans. 5. None of the extracts showed antimicrobial activities against Escherichia coli. We observed antimicrobial activities of Chungyulsodokeum and its composition against Streptococcus mutans, Staphylococcus epidermidis, Staphylococcus aureus.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.202-209
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• 1997

The mechanical properties of Ti-6Al-4V greatly vary for changes of microstructures. Therefore, when manufacturing components with this material, it is important to understand the influence of process parameters to the resulting microstructures. In the present investgation, it was attempted to relate the process parameters with the microstructures in a hot forged Ti-6Al-4V disk. The investigation was carried out by a rigid thermo-viscoplastic FEM analysis, flow stress measurements and microstructure studies. It was found that the dynamic recrystallization would hardly occur in this material and that variations of strain, strain rate and temperature of several locations in the disk were below the assumed dynamic recrystallization zone. These findings confirmed the experimental obervations that the microstructures in the disk were only deformed without being recrystallized.

• Journal of the Semiconductor & Display Technology
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• v.19 no.1
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• pp.67-72
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• 2020

This study analyzes the method of adhesion and improvement between heat.er and RF filter in PE-CVD equipment through TRIZ method and proposes a solution. TRIZ Solution such as function analysis, 9-window matrix, ASIT, and Root cause analysis were used. The contact temperature between the heater and the RF filter was 20% and the surface temperature was lowered to 5.7℃, suggesting an improvement method for the thermal expansion of the PE-CVD equipment hot zone.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.762-768
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• 2011

We use floor radiant heating system in the house of commons in winter Floor radiant heating system, which transfer heat by radiation, is one of the energy efficient and comfortable systems that. Floor radiant heating system is configured to be controlled by the room for energy-saving. Proper flow rate to a comfortable heating in the room is important. However, Using a constant speed circulation pump in separate rooms, heating system may cause an imbalance because of the difference of length of coil when operating in the rooms. In this study, our Research team examined heating imbalance due to the variation length through the coil length changes and flow control of the circulation pump.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.704-709
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• 2004

The wear behavior and the mechanical property of Cu-$TiB_2$ composites were examined. Cu-$TiB_2$ composites were fabricated by hot extrusion and cold drawing with $TiB_2$ contents(1$\∼$5vol.$\%$) and the size of $TiB_2$ particles(10$\mu$m and 20$\mu$m). The pin-an-disk wear test was carried out under dry sliding wear conditions which loads varied with from 20N to 100N. At the time, counterpart wear material used SM45C. The experimental results showed that the friction coefficient and wear rate decreased with increasing the $TiB_2$ contents and decreasing the size of $TiB_2$ particle. Also, the depth of plastically deformed zone decreased with increasing the $TiB_2$ contents and decreasing the size of $TiB_2$ particle.

• Structural Engineering and Mechanics
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• v.44 no.4
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• pp.417-429
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• 2012

Taking the superficial temperature increment as the major fatigue damage indicator, the infrared thermography was used to predict fatigue parameters (fatigue strength and S-N curve) of welded joints subjected to fatigue loading with a high mean stress, showing good predictions. The fatigue damage status, related to safety evaluation, was tightly correlated with the temperature field evolution of the hot-spot zone on the specimen surface. An energetic damage model, based on the energy accumulation, was developed to evaluate the residual fatigue life of the welded specimens undergoing cyclic loading, and a good agreement was presented. It is concluded that the infrared thermography can not only well predict the fatigue behavior of welded joints, but also can play an important role in health detection of structures subjected to mechanical loading.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.356-362
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• 1994

We developed a computer controlled Czochralski puller which automated entire crystal growing processes. Crystal weighing technique was employed for an automatic diameter control. The performance of the system was evaluated by the growth of $LiNbO_3$ single crystals.