• Fashion & Textile Research Journal
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• v.10 no.2
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• pp.254-259
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• 2008

Poly(ethylene-co-vinylacetate)(EVA) microspheres were prepared by a thermally induced phase separation. The microsphere formation occurred by the nucleation and growth mechanism in the metastable region. The diluents used were toluene. The microsphere formation and growth was followed by the cloud point of the optical microscope measurement. The microsphere size, which was obtained by SEM observation and particle size analyzer, became decreased when the titanium dioxide($TiO_2$) concentration was higher. The deodorizing function of the prepared fabrics was studied by the determination of the decomposing capability for $NH_3$. The deodorant activity of these deodorizing fabrics was measured by chromogenic gas detector tubes. The deodorant activity of $NH_3$ increased with increasing $TiO_2$ concentration of EVA microsphere.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.2
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• pp.1-6
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• 2011

This study aims at predicting structural behaviors of RC (Reinforced Concrete) beams retrofitted with hybrid FRPs (Fiber Reinforced Polymers). Toward this goal, structural analysis for the RC beams retrofitted with hybrid FRPs are performed and validated using existing experimental data. For the analysis, failure models due to debonding of FRPs and concrete separation are implemented within FE (Finite Element) model, based on Smith and Teng, model, and Teng and Yao model, respectively. Nonlinear material and geometrical effects are also included in the analysis. The suggested modeling approaches are able to predict structural behaviors of RC beams retrofitted with hybrid FRPs similar to the experimental data, however, a numerical model needs to be developed in order to predict failure strength of RC beams retrofitted with hybrid FRPs accurately.

• Membrane Journal
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• v.23 no.5
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• pp.375-383
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• 2013

Nanomaterials having large surface area, uniform dimensions or pores can be utilized in various membrane applications Amongst them, many studies have been focused on nanocarbon materials: graphene, graphene oxide and carbon nanotubes. Carbon nanotubes, one-dimensional structure, have excellent characteristics in thermal, chemical and mechanical strength properties. However, carbon nanotubes was mainly used to reinforce mechanical properties of polymer materials in previous applications. In contrast to previous studies, we focused on modified carbon nanotubes/polyethylene glycol diacrylate (PEGDA) composite membrane preparation for improvement of permeability and selectivity on gas separation.

• Resources Recycling
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• v.10 no.6
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• pp.43-52
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for Plaster boards or cements from waste Plaster board. Gypsum could be Preferentially disintegrated to gypsum needle in $10\mu\textrm{m}$ or less size by hydration after the dehydration of crushed waste Plaster board. The finer the gypsum needle, it is easier to remove coarse impurities and to recover the gypsum needle. The optimum conditions for obtain the finer gypsum size were dehydration rate of 75~85%, solid concentration at hydration of 10~15%, agitation speed of 250~400 rpm, crushing size before dehydration of 2 cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield as the undersize of 325 mesh wet screening followed by the dehydration-hydration process performed at the conditions of dehydration rate of 80%, solid concentration at hydration of 15%, agitation speed of 300 rpm, crushing size before dehydration of 2 cm or less. After the recrystallization of recovered gypsum, Plate-like gypsum of $151\mu\textrm{m}$ size with 99.49% grade was obtained as the oversize of 270 mesh in a wet screening.

• Journal of the Korean Applied Science and Technology
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• v.24 no.1
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• pp.92-97
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• 2007

The present paper deals with gaseous carbon dioxide separation by a commercial adsorbent: X-type zeolite. Experimental work was carried out at an ambient condition focusing on how well meeting to the national guideline. A few types of reactor and material were examined, and practical capability was found in a granular bed type reactor with the flow of 2.5 CMM. An optimum design of reactor and adsorbent could provide the required concentration, less than 2500 ppm, for the continuous operation up to 10 hours. More work including automatic regeneration is now underworking.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.89-96
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• 2010

The separation of $TiO_2$ wastewater carried out by an electrocoagulation/flotation process, which had various operating parameters. The effect of electrode material (aluminum and four dimensionally stable electrode), applied current (0.07~0.5 A), electrolyte concentration (0~1 g/L), solution pH (3~11), initial turbidity (1000~20000 NTU) and suspended solid concentration (5000~25000 mg/L) were evaluated. Turbidity removal efficiency of the soluble anode (aluminum), which could produce metal ions, was higher than that of the dimensionally stable electrode. Considering operation time, turbidity removal and electric power, optimum current was 0.19 A. The more NaCl dosage was high, the less electric power was required. However, optimum NaCl concentration was 0.125 g/L considered removal efficiency, operation time and cost. Initial $TiO_2$ concentration did not affected turbidity removal on the electrocoagulation/flotation operation. The electrocoagulation/flotation process was proved to be a very effective separation method in the removal of $TiO_2$ from wastewater.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.165-166
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• 2014

The Composite waterproofing began to rise gradually 2000s in domestic. However, the sheet-membrane composite waterproofing method also acts as an abutment vulnerability that was a problem in a single method, and had the problem of damage to the formation of leakage paths. The existing non-overlap method, through vigorous research abutting sheet shall or could be developed to improve the seal performance of this method with the I-type joint coating material. Nevertheless, it has an integral top coat paint membrane and a sheet abutment limitation, damage to the upper membrane is damaged junction coating membranes has been generated. In this study, a method that has a layer of insulation on the joint bond breaker concept development, and to determine the physical properties with insulated joints to determine the breaking off of the upper joint is damaged coating membrane and tensile performance.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.849-856
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• 1992

We prepared a simple, economic and versatile preparative system for an enantiomeric separation. Hydrophobic amino acid enantiomers were resolved in the preparative scale by a centrifugal liquid chromatography on the N-hexadecyl-L-proline coated reversed phase. The factors controlling the retention and resolution of racemic amino acids such as the concentration of Cu(Ⅱ), pH of the eluent, the type and content of organic modifier, and rpm of CLC were examined. Several mg of hydrophobic amino acid enantiomers were separated preparatively. To separate all of different amino acid enantiomers, various coating material will be investigated.

• Fashion & Textile Research Journal
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• v.10 no.3
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• pp.371-376
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• 2008

Poly(ethylene-co-vinylacetate) (EVA) microspheres were prepared by thermally induced phase separation (TIPS) in toluene. The microsphere formation occurred by the nucleation and growth mechanism in metastable region. The effects of the concentration and component of the polymer and cooling rate on microsphere formation were investigated. The microsphere formation and growth were followed by the cloud point of the optical microscope measurement. The microsphere size distribution, which was obtained by particle size analyzer, became broader when the polymer concentration was higher, the content of vinyl acetate in EVA copolymer was higher, the cooling rate of EVA copolymer solution were lower. The content of disperse dye in EVA microsphere was obtained by TGA thermal analysis, the dye content of EVA15 and EVA18 were 3.5 and 2.0 wt% respectively.

• Journal of Magnetics
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• v.8 no.4
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• pp.146-148
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• 2003

Multilayered films of Co/Pd have been studied as a candidate material for a high density perpendicular recording medium due to higher anisotropy energy. However, high exchange coupling among grains results in large transition noise. To reduce the exchange coupling and grain size, addition of 3rd elements and physical separation of grains have been attempted. In the present paper, effects of sputtering pressure, Co sublayer thickness and Pd underlayer thickness on magnetic properties and microstructures were studied. It was found that by increasing sputtering pressure from 5 mTorr to 25 mTorr, Ms decreased to one half and coercivity increased more than 5000 Oe. The increase of the coercivity is associated with physical separation of grains by high pressure sputtering. Ms per volume of Co for Co/Pd multilayered film deposited at 25 mTorr shows continuous decrease with increasing Co sublayer thickness. This was related to void formation and intermixing of Co/Pd interface. Also, effect of Pd underlayer thickness on magnetic properties will be discussed.