• Carbon letters
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• v.26
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• pp.25-30
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• 2018

The dielectric medium used in electrophoretic displays (EPDs) is required to be an environmentally friendly solvent with high density, low viscosity, and a large electric constant. Hydrofluoroether, a highly fluorinated solvent with eco-friendly characteristics, is regarded as a viable alternative medium for EPDs, owing to the similarity of its physical properties to those of the conventional EPD medium. Surface modification of particles is required, however, in order for it to disperse in the charged solvent. Also, positive/negative charges should be present on the particle surface to enable electrophoretic behavior. In this study, carbon black particles wrapped with positively charged nitrogen (N-CBs) were fabricated by a simple hydrothermal process using a poly(diallyldimethylammonium chloride) solution as a black coloring agent for the EPD. The dispersion behavior of N-CBs was investigated in various solvents.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.65-66
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• 2003

Ternary blend fibers (TBFs) based on melt blends of PEN, PET, and TLCP were prepared by melt blending and spinning to achieve high performance fibers. The reinforcement effect and the TLCP fibrillar structure resulted in the improvement of mechanical properties for TBFs. Molecular orientation was an important factor in determining the tensile strength and modulus of TBFs. Another part of this research is silica nano-particle filled PEN composites were melt-blended to improve mechanical and physicalproperties, and processability. The tensile modulus and strength were improved adding silica nano-particles to the PEN. The decreased melt viscosity by the fumed silica resulted in the improvement of the processability. The fumed silica may act as a nucleating agent in the PEN matrix.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.676-686
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• 2010

Damage Cases of variously type are reported that the ground subsidence is caused by the underground cavities at structure and construction works in lime stone or abandoned zone. A underground cavities by direct for zone having an effect on structure have been filled with cement agents. But this measure is urgently needed in materials and work methods, because ground water pollution at water down fillings and flow out, ground disturb at high participle, damage of farms and fishery. The research confirm application of filling method and filling materials of environmentally friendly and economical by Hi-FA new materials have both liquidity and viscosity from case reinforcement in APT site, Gunsan.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.303-308
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• 2001

Recently, concrete structures have become larger and higher and are demanding high performance concrete with lower heat to prevent thermal cracking, far greater workability, high strength and durability, Application of low heat portland(Type IV) cement for the high performance concrete is the best solution to satisfied those requirements. Here are explained the effect on the properties of high flowing concrete using low heat portland cement by material and mixing variations. Variables for sensitivity test were selected items like finess modulus of aggregates, particle size of limestone powder, unit water, superplasticizer, viscosity agent and concrete temperature. The results of this study were be applied to slurry wall of #215 and #216 of underground LNG tank in Inchon.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.337-342
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• 1999

The Purpose of this study is to evaluate the strength characteristics of polyurethane(PUR) mortar cured under low temperature condition. PUR mortars are prepared with various catalyst content, methylene chloride(MC) content as a viscosity reducing agent, and curing age at low temperature condition of $0^{\circ}C$, -5$^{\circ}C$ and -1$0^{\circ}C$, tested for working life, compressive and flexural strengths. From the test results, the catalyst and MC contents affect the degree of hardening and blowing of PUR mortar. Strengths increase with an increasing catalyst content at low temperature. Flexural and compressive strength of PUR mortar are about 177kgf/$\textrm{cm}^2$ and 490kgf/$\textrm{cm}^2$ respectively at curing temperature of -1$0^{\circ}C$ with catalyst content of 0.4%. Therefore, it is apparent that this PUR mortars have a sufficient strengths for repair of concrete structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.567-570
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• 2000

This study is designed to manufacture the continuous foamed concrete and the sound absorption characteristics investigation due to continuous voids ratio. According to the results of experiment, it was shown that continuous voids of the foamed concrete has the influence of the amount used of foaming agent, the viscosity and flowability of cement paste, and also is shaped by cohesive power of bubbles. Also the sound absorption ratio of the foamed concrete is subject to increase as the density becomes low by raising the continuous voids ratio. The cement paste with low water-cement ratio and high cement fineness are very effective to prevent weak strength of formed concrete caused by the increase of the porosity.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.177-182
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• 1998

In this study, We compare material properties of Self-compacting concrete using Korean Belite cement with Japanese. Self-compacting concrete consolidates densely by virtue of its own weight at the location where concrete compaction cannot be carried out. Material properties of Korean and Japanese Belite cement are very similar but compatibility with superplasticizer and viscosity agent are some different. Before the batch mix, the compatibility must be checked as fresh concrete properties. For the concrete test results, Korean Beilite cement is suitable to product High performance concrete.

• Fibers and Polymers
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• v.2 no.1
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• pp.148-151
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• 2001

The effect of main chain structure of anion-containing copolyesters on the properties of copolyester sizing agents was investigated. The copolyesters were prepared by conventional two step polymerization technique from DMT, DMI, DMS, EG, and DEG. The copolyesters synthesized were characterized by atomic absorption spectroscopy, $^1$H-NMR Spectroscopy, GC, FTIR Spectroscopy, and DSC. The solubility decreased as the DMT content increased. The copolyesters having DMT:DMI = 1:1 showed the minimum viscosity. The effect of EG content on the solution stability was not clear and the samples having high DMI content showed better solution stability. The water resistance was best when only DMI and EG were used, while it was worst when DMT:DMI was 1:0.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.140-141
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• 2017

This study is based on the evaluation of a single component injection type adhesive repair material and a new 2 component type used in leakage of underground concrete structures. The studies showed that based on different mix ratio of the 2 component type adhesive sealant comprised of an asphalt main and latex mixture agent the viscosity of the material compound differed significantly. Based on a permeability testing, injection and economic efficiency, and performance, the appropriate ratio was determined to be 6:1 and was proceeded to the KS F 4935 evaluation method. The 2 component type adhesive sealant uses a static mixer and a cartridge type container for the injection procedure and was able to satisfy the evaluation criteria outlined in the KS F 4935 standard.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.775-780
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• 2003

The propose of this study is to discover concrete secondary products for proper mixing by lightweight concrete. The standard of water ratio 50% and weight substition 0%, 10%, 20% by Fly-ash. When produce manufactures, there use for maintain its form weight substition and addition among the viscosity agent each Silica-fume and Hydroxy propyl methyl cellulos. Testing method was to operate slump, air content, compressive strength test, rapid freezing and thawing test. The result of this study is appeared when substition Fly-ash generally it had better use Silica-fume.