• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.96-97
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• 2016

As coal fly ash emissions have increased due to additional constructions of domestic heat power plants, the amount of embedded reject ash (Rj henceforth) is increasing as well. Most Rj is embedded, so if it is used as an alternative admixture instead of cement, embedded quantities will decrease, leading to economic and environmentally positive effects. Therefore this study conducted an experiment to contemplate the usability of Rj ground in the Los Angeles abraser, and what effects ground Rj has on the engineering properties of poor-mix mortar. The result was that as the number of grinding turns increased, liquidity, air quantity and intensity were improved, proving Rj a possible alternative admixture to cement.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.831-834
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• 2002

A novel ceramic synthesis technique, combustion synthesis, is explored to produce an orange-emitting $SnO_2:Eu^{3+}$ phosphors. This technique involves a reaction of metal salts with a citric acid as an organic fuel. The variation of the ratio of citric acid to metal introduces change in reaction temperature and atmosphere of the combustion reaction, which in turn influences crystallinity and luminescence properties of the final products significantly. And the heat treatment of the as-synthesized product improved the CL intensity of the products. Especially, the sample treated at above 1100 $^{\circ}C$ shows an orange-emission, which is attributed to the formation of single phase and well-crystallized $SnO_2$:Eu in rutile structure.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.1
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• pp.79-86
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• 2015

The purpose of this study is to evaluate structural integrity of a weldment which is partially screwed and then welded. Two finite element models are constructed and solved: operating temperature and internal pressure are considered in the first simple model, and welding process and normal operating condition including heat-up process are simulated in the second model. Structural integrity assessment criteria are satisfied with both finite element models, therefore the repair weldment finely sustains structural integrity of this assembly and prevents leakage. Stresses are dramatically increased when weld residual stress is considered, but it should be considered as a secondary stress.

• Journal of the Korean Society of Combustion
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• v.15 no.2
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• pp.19-26
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• 2010

Combustion behavior of pulverized coal particles in a post-combustion gas reactor was investigated. Radiation emission from coal particles were analyzed by direct photograph and $CH^*$ radical chemiluminescence intensity. Coal particles were sampled during the combustion and were observed by scanning electron microscopy (SEM) and cross section micrograpy technique. Two coal types(one bituminous and one subbituminous coals typically used in the Korean power plants) were tested at typical combustion environment. Gas flow conditions were controlled to represent temperature and oxygen concentration. Experimental data were discussed along with conceptual descriptions of pulverized coal combustion, where particle heat-up, release and combustion of volatiles, and char combustion were sequentially progressed.

• The Journal of the Korean Society for Microbiology
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• v.21 no.1
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• pp.145-149
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• 1986

The development of delayed-type hypersensitivity(DTH) reaction to Staphylococcus aureus in mice was studied, Mice received 3 injections of $10^8$ viable S. aureus subcutaneously showed a marked footpad swelling when mice were challenged with $10\;{\mu}g$ staphylococcal protein antigen into footpad(The percent increase of footpad thickness at 24 h after challenge wsa 35% approximately). Histological observation of footpad of immunized mice showed a marked thickness of subcutaneous tissue due to edematous reaction and massive infiltration of lymphocytes and neutrophils which are characteristic cells in DTH reaction. Intensity of DTH reaction of mice immunized with viable bacteria was much higher than that of mice immunized with staphylococcal protein or heat-killed bacteria. The DTH reaction to S. aureus could be transferred to normal recipient mice by both spleen cells and lymph node cells.

• Journal of the Korean Society of Visualization
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• v.9 no.3
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• pp.16-23
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• 2011

Experiment and numerical investigation are performed on swirling water flow in a vertical circular tube. This kind of flow is used in heat exchangers, combustion chambers, thermal power plants, and other mechanical equipment to move slurries or to convey materials. However, limited information on swirling flow in vertical circular tubes is available. In the current paper, the three-dimensional particle image velocimetry(PIV) technique is employed to compare the measured velocity profiles of water along the vertical circular tube with those of non-swirl flow. In addition, computational fluid dynamics(CFD) code was applied to calculation of the flow velocities with swirl.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.525-527
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• 2005

The LED light source has many excellent advantages for the application of LCD backlight module. As we know, the operational temperature can significantly influence the characteristics of LEDs. Heat can decrease LED's output light intensity and make its dominant wavelength (${\lambda}d$) drift. These two factors make display's color temperature change and induce different NTSC results. Here, we perform an important relation between NTSC and the above two factors of LED-LCD display.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.813-816
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• 1988

This study is to investigate the adhesive strength of composite material's interface on the experimental methode of tree growth in the material. The results are as follows 1) The irradiations of ultrasonic energy cause the mechanical vibration in the polymer composite materials of fluid state, so then bring about physical dispersion and heat for inorganic materials, being supposed to produce chemical interlinking reaction, decreasing of voids between filler and matrix. 2) As the intensity of ultrasonic energy and its irradiated time are larger, the tree inception and breakdown voltages increase and the tree growing is slower. so we obtain that the interface adhesive force can be strengthened by the irradiation of ultrasonic energy.

• The KSFM Journal of Fluid Machinery
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• v.7 no.4 s.25
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• pp.32-39
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• 2004

This study deals with the Benard Flow of Magnetic Fluids in a rectangular cavity which the ratio between height and width is 1 : 4 and the base side or left side is a heating face while other sides are to be cooling faces. When Magnetic field was equally impressed, considering the internal rotation of the elementary ferromagnetic particle, we found the following result from the numerical analysis of the GSMAC algorithm applied to the equation of the magnetic fluid. Benard flow is controlled by intensity and direction of magnetic fields, and critical point appears when especially magnetic field with a heating base and side area near H=-7000 and H=-10000 is applied.

• Carbon letters
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• v.16 no.2
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• pp.121-126
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• 2015

Carbon fibers are prepared by stabilizing pitch fibers accompanying electron beam (E-beam) irradiation. The carbon fibers pretreated by E-beam irradiation achieve a higher stabilization index than the carbon fibers that are only heat-stabilized. In addition, the carbon fibers subjected to E-beam irradiation in the stabilization step exhibit a comparable tensile strength to that of general purpose carbon fibers. The carbon fibers pretreated with an absorbed dose of 3000 kGy have a tensile strength of 0.54 GPa for a similar fiber diameter. Elemental, Fourier-transform infrared spectroscopy, and thermogravimetric analyses indicate that E-beam irradiation is an efficient oxidation and dehydrogenation treatment for pitch fibers by showing that the intensity of the aliphatic C-H stretching and aromatic $CH_2$ bending (out-of-plane) bands significantly decrease and carbonyl and carboxylic groups form.