• Journal of the Korean Home Economics Association
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• v.11 no.1
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• pp.26-43
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• 1973

This study was carried out on the Sewbility of Urethane Foam usually used as coldproof lining. The Sewability was estimated with the Puckering Grade and Seam Efficiency according to the thicknes of urethane foam, fineness and material of sewing thread, and the sort of covering fabric. The result shows the following ; 1. The thick foam proportinally shows the low Puckering Grade. 2. Effect on the sewability is small in fineness of sewing thread but large in material. Especially silk thread shows the greatest sewability in foam sewing. When the material of covering fabric is same as that of sewing thread (for example ; p/c fabric and p/c thread) the sewability is excellent in special. 3. Taffeta in covering foam is not suitable to foam sewing, satin and twill show superior sewability without reagrd to the thickness of foam. 4. In case of sewing foam covered with tricot, optimum thickness of foam and fineness of sewing thread through pretest must determine. 5. The thicker foam is the better seam efficiency tends, and Seam Efficiency largely effects to the strength of the sewing thread itself. 6. The seam Efficiency can heighten with the strength of sewing thread in proportion to that of covering fabric.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1816-1821
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• 2003

The sapphire wafer for blue light emitting device was manufactured by the implementation of the chemical and mechanical polishing process. The surface polishing of crystalline sapphire wafer was characterized by zeta potential measurement. The reduction process with the alkali slurry provides the surface chemical reaction with sapphire atoms. The poly-urethane pad also provides the frictional force to take out the chemically-reacted surface layers. The surface roughness was measured by the atomic force microscope and the crystalline quality was characterized by the double crystal X -ray diffraction analysis.

• Journal of KSNVE
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• v.7 no.5
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• pp.781-787
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• 1997

A new method is presented to determine two fundamental acoustic quantities of sound-absorbing materials such as characteristic impedance and propagation constant. In this study, the surface acoustic impedances of sound-absorbing materials are measured using the impedance tube and the anechoic chamber to determine the above acoustic quantities. The measured results are given for two typical sound-absorbing materials(glass wool and urethane foam) int the frequency range between 150 and 1, 600 Hz. The results are verified by other two known methods, which are Smith & Parrott method and Utsuno et al. method. The absorption coefficients calculated from the empirical models(Miki model for glass wool and Jung model for urethane foam) and two quantities by present method are in good agreement with the measured values.

• Elastomers and Composites
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• v.51 no.2
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• pp.154-160
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• 2016

The four different vinyl monomers in the reaction of isocyanate-terminated polyurethane prepolymer were used for the preparation of macromonomers and successfully employed in the dispersion polymerization of styrene. The chemical structures of vinyl monomer in macromonomers influenced on the polystyrene particle characteristics, such as the conversion, weight average molecular weights ($M_w$), polydispersity index (PDI), weight average diameter ($D_w$), and uniformity. The conversion of polystyrene increased with amounts of methyl group in vinyl monomer. Also the uniformity of polystyrene particles increased with amounts of methyl group in vinyl monomer.

• Journal of the Korean Chemical Society
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• v.25 no.6
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• pp.361-366
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• 1981

For the urethane formation reaction of isocyanate with alcohol, orientation of approach of alcohol toward isocyanate was investigated theoretically by means of MO method. As a result of EHT and CNDO/2 calculations, it was found that the reaction proceeding via 4-centered mechanism, in which ROH is coplanar with isocyanate plane was energetically favored. It was also shown that the oxygen of ROH attacks the isocyanate carbon prior to the formation of 4-center complex. The reaction was found to be a charge controlled one.

• 보존과학연구
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• s.27
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• pp.215-226
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• 2006

In the field conservation treatment, it is important that the method chosen to lift an object out of the ground depends on its surrounding weather, strength, size, composition, and condition. This paper describes a physical support(Urethane bandage, De naturation - polyisoprene resin) created for lifting delicate relics in this field. The advantage of Urethane bandage method is of conveniently portable size, and it's convenient for use, while curing time is very fast.(approx. 5~10minute)Denaturation -polyisoprene resin is able to be soft by the hot water(approx. $60^{\circ}C$ ). so it's good to stick to the relic surface of an indeterminate form. The results of use of these reinforcement methods are of utility value.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.63-70
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• 2003

It is very important to improve the insulation performance of curtain wall anchoring unit since it is composed of materials with high thermal conductivity, such as aluminium, steel and so on. This study aims to evaluate the heating energy performance and economical efficiency of various alternatives which are different in position and material of insulation. As results, alternative of inserting the urethane washer & pad and coating the anchoring unit with urethane foam can improve the heating energy performance and L.C.C(Life Cycle Cost) by 6.33% and 0.95%, respectively, as compared with the existing case.

• Journal of the Korean Applied Science and Technology
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• v.28 no.2
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• pp.240-246
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• 2011

UV-Curable hybrid coatings were synthesized to improve the surface properties of plastic film. Organic-inorganic coating solutions were prepared by the sol-gel method using urethane-acrylate oligomer, acrylate monomer, photo initiator and tetraethoxysilane (TEOS). Methacryloyloxypropyltrimethoxysilane(MPTMS) was used as a silane coupling agent to improve chemical interaction between inorganic phases and UV curable acrylate. In this study, the surface hardness and adhesive properties were improved with the use of inorganic component. The experimental results showed that UV-Curable hybrid films containing aliphatic urethane oligomer, hexanedioldiacrylate, trimethylolpropanetriacrylate, hydroxy dimethyl acetophenone exhibited good surface properties. Also, the optimum curing conditions were investigated.

• Journal of the Korean Applied Science and Technology
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• v.28 no.2
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• pp.203-212
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• 2011

In this study we experimented that how chain extension influences to waterborne urethane-acrylic hybrid resin for leather garment coatings. We knew that polyurethane-acrylic hybrid resins had 5 grades of solvent resistance. Tensile strength measured in the polyurethane-acrylic resin(EDA 5.37 g, 1.928 kgf/$mm^2$) had the most strong strength. Also polyurethane-acylic hybrid resin(EDA 5.37 g. 30.2 mg. loss) had better result than other hybrid resins. EDA contents higher, we obtained low elongation and low flexibility. In this result, chain extension of waterborne polyurethane-acrylic hybrid resin showed the effect in leather coating with ratio of EDA.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.5
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• pp.372-381
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• 2003

This study aims to find out the optimized insulation thickness of refrigerated warehouse with different envelope structures (RC and PC wall) and insulation materials (urethane and icynene). Each of them is compared according to the thickness of insulation (100, 150, 200 mm/50 or 250 mm) and the temperature of cold storage room (0, -6, -15$^{\circ}C$). As results, it is proved to have the best economical efficiency in life cycle cost when PC wall with thickness of 100 mm (0 and -6$^{\circ}C$) and 150 m (-15$^{\circ}C$) urethane, respectively, are applied.