• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.622-627
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• 2013

Colloidal silica is used in various industrial products such as chemical mechanical polishing slurry for planarization of silicon and sapphire wafer, organic-inorganic hybrid coatings, binder of investment casting, etc. An accurate determination of particle size and dispersion stability of silica sol is demanded because it has a strong influence on surface of wafer, film of coatings or bulks having mechanical, chemical and optical properties. The study herein is discussed on the effect of measurement results of average particle size, sol viscosity and electrophoretic mobility of particle according to the volume fraction of eight types of silica sol with different size and surface properties of silica particles which are presented by the manufacturer. The measured particle size and the mobility of these sol were changed by volume fraction or particle size due to highly active surface of silica particle and change of concentration of counter ion by dilution of silica sol. While in case the measured sizes of small particles less than 60 nm are increased with increasing volume fraction, the measured sizes of larger particles than 60 nm are slightly decreased. The mobility of small particle such as 12 nm are decreased with increase of viscosity. However, the mobility of 100 nm particles under 0.048 volume fraction are increased with increasing volume fraction and then decreased over higher volume fraction.

• Journal of the Korea Concrete Institute
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• v.27 no.5
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• pp.531-539
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• 2015

Properties of normal-strength mortar containing coarsely-crushed coal bottom ash considering standard particle size distribution of fine aggregate were investigated. Mortar containing raw bottom ash was applied as a reference. By crushing the bottom ash with a particle size larger than fine binder but smaller than fine aggregates, i.e., coarse-crushing, water absorption and specific gravity of the particles could be controlled as similar levels to those of natural fine aggregates. Workability and strength of the mortar were not changed and even increased when the coarsely-crushed bottom ash was added considering standard particle size distribution in Standard Specification for Concrete, while those were decreased when raw bottom ash was added without any treatment. When a replacement ratio of coarsely-crushed bottom ash was less than 30 vol.%, there were no significant decrease in dynamic modulus of elasticity and dry shrinkage of the mortar.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04a
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• pp.7-16
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• 1999

The aim of this research was to evaluate the influences of coating components and structures on ink absorbency. The ink absorbency was measured as porosity, K&N ink absorption, gloss and ink set-off. In order to obtain the relationship between the coating structure and the ink absorbency, the binder level was adjusted and two types of pigments were examined. One of the pigments was known to make the porous coating structure and the other one had strong ink affinity. The effects of coating components were studied by applying six different types of latex and various additives . In this research, CLC(cylindrical laboratory coater) and Prufbau printability tester were used. It was found that the decreasing latex dosage and introducing porous pigment were effective solutions to increase ink absorbency. However, the ink absorbency could not be improved by applying the fine pigment even though it had strong ink affinity. Among the characters of the latex, particle size and surface tension were found to have the strong effect on ink absorbency. The ink absorbency increased with large particle size and low surface tension latex. The additives were varied and it was found that applying to the top coating was effective.

• International Journal of Highway Engineering
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• v.6 no.2 s.20
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• pp.15-24
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• 2004

Oxidation causes increment of the quantity of large molecular size or LMS in asphalt and is a major reason for hardening of asphalt binder. An extended service life of pavement on a road is expected by reducing oxidation of binder. Oxidation of binder occurs during hot mixing with aggregates before placement on road and then during in-service after the asphalt pavement is constructed. Quantitative increase of LMS as result of aging after RTFO and PAV was analyzed based on the data from high-pressure gel-permeation chromatography (HP-GPC). Polymer modified asphalt (PMA) after RTFO procedure showed 20-30% increment in LMS and then after PAV procedure more than twice, although the percentage of increment was different according to asphalt brand and grade. The PMAs containing LDPE or SBS, which showed a great mechanical property improvement in previous studies, were selected for characterizing PMA aging In this study. Considerably reduced increment of LMS was observed from the PMA containing LDPE after RTFO and PAV procedures. The GPC result showing the binder with less LMS increment means that the asphalt while being mixed with LDPE was aged less during the aging treatment. The dispersed particle of LDPE in asphalt cement seems to disturb oxidative aging reaction and evaporation.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.340-348
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• 2009

The recycled polyethylene was used for making wood-plastic composite panels. In this experiment, the sizes of wood particles used were 1/32", 1/4" and 1/2" in mesh number, and the contents of the recycled polyethylene were 10%, 30% and 50%. The physical and mechanical properties of the composite panels were investigated. At a given content of recycled polyethylene, the density of composite panel decreases with the increase of wood particle size. The thickness swelling and water adsorption decrease with the increase of recycled polyethylene, where significantly lower at 10%, compared with at 30%. In the water soaking experiment for 14 days, the dimensional stability of composite panel appeared good in the composite panel with recycled polyethylene content of 30% or higher. As the content of recycled polyethylene increases, the internal bonding strength and the modulus of rupture in bending strength increases. In SEM, the molten recycled polyethylene showed interlocking action through its penetration into tracheid openings including pits as well as binder between wood particles as the matrix material, thus increasing bonding strength and improving the physical and mechanical properties of composite panel.

• Journal of the Korean Ceramic Society
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• v.27 no.6
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• pp.755-762
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• 1990

The tungsten paste was printed on the surface of 92% alumina sheet which was made by type casting process. The printed tungsten was bonded on the Al2O3 by co-firing in reducing atmosphere. During the co-firing, the binder burn-out was easier in wet H2 atmosphere than in dry H2, which affected sintered density. In practically, the use of wet H2 above 100$0^{\circ}C$ was beneficial for density of alumina and bond strength. This phenomena occured more distinctly when atmosphere varied from dry H2 to wet H2 than varied dew point in wet H2. In wet H2, the improvement in bonding strength can be attributed to good glass migration into the metal layer due to inhibition of the tungsten particle growth, with increase of alumina density, at the temperatrue higher than 100$0^{\circ}C$.

• Advances in concrete construction
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• v.16 no.3
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• pp.169-176
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• 2023

The aim of the study was to establish the influence of particle size, chemical and phase composition of fine microspherical high-calcium fly ash (HCFA), as well as superplasticizer content on the strength of cementless composite materials based on 100% HCFA and mixtures of HCFA with Portland cement (PC). For the initial HCFA fractions, the particle size distribution, chemical and quantitative phase composition were determined. The compressive strength of cured composite materials obtained at W/B 0.4 and 0.25 was determined at a curing time of 3-300 days. For cementless materials, it was found that a change in the particle size d90 from 30 ㎛ (fraction 3) to 10 ㎛ (fraction 4) leads to an increase in compressive strength by more than 2 times. Compressive strength increases by at least another 2.2 times with the addition of Melflux 5581F superplasticizer (0.12%) and at W/B 0.25. The HCFA-PC blends were investigated in the range of 60-90% HCFA and the maximum compressive strength was found at 80% HCFA. On the basis of 80% HCFA-20% PC blend, the samples of ultra-high strength (108 and 150 MPa at 28 and 100 days of hardening) were obtained with the addition of 0.3% Melflux 5581F and 5% silica fume. The quantitative phase composition was determined for composite materials with a curing age of 28 days. It has been established that in a sample with ultra-high strength, a more complete transformation of the initial phases of both HCFA and PC occurs as compared to their transformation separately.

• Journal of the Korean Society of Radiology
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• v.3 no.2
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• pp.11-16
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• 2009

Mercury Iodide as good sensitivity at radiation and has an easy peculiarity that operates at low voltage for other photoconductors(a-Se, a-Si, Ge, etc) Based on this characteristic, we studied about an efficiency of the digital x-ray detector in acccordance with the thickness of photoconductor. To solve the problem that is difficult to make a large area film using PVD(Physical Vapor Deposition)method, we used a PIB(Particle In Binder)method. To make a binder paste, we used a PVB(Polyvinylbutyral) as a binder and a DGME(Diethylene Glycol Monobutyl Ether), DGMEA(Diethylene Glycol Monobutyl Ether Acetate) as a solvent. Using this binder paste, we made a polycrystal mercury iodide film that has an each thickness. To evaluate the electrical properties of this films, we measured a darkcurrent, sensitivity and SNR(Signal to Noise Ratio). Mercury iodide film of the 200um thickness has good electrical properties as a result of the measurement. From this result there is a good chance that replace the existing a-Se(Amnorphous seleinum; a-se) with the mercury iodide.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.429-433
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• 2014

In this study, the morphology and the x-ray quantum efficient of mercury oxide (HgO) and lead oxide (PbO) sensors derived by particle sedimentation method were discussed. In the pursuit of this purpose, we investigated the electrical characteristics and the x-ray quantum efficiency of various thicknesses of HgO and PbO films in mammographic x-ray energy. We have therefore developed a particle-in-binder sedimentation method of fabricating large area polycrystalline films onto transparent glass substrates coated with indium tin oxide. We are currently optimizing the growth method to improve the quantum efficiency with the ultimate goal of obtaining as quantum efficiency close to that of single crystal performance. Our future efforts will concentrate on optimization of large area film growth techniques specifically for deposition on a-Si:H flat panel readout arrays.

• Journal of Adhesion and Interface
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• v.14 no.1
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• pp.28-35
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• 2013

In this study, we produced heat-shield coating materials using surface-treated Ga-doped ZnO (GZO) and investigated the dispersity of particle, visible light transmittance, ultraviolet light cut off, infrared light cut-off, heat-shielding property by surface-treating compounds and treatment conditions. In the case of using IPA or acryl binder for heat-shield coating, the dispersity of inorganic oxide particles was poor but in the case of using surface-treated inorganic oxide particles by hybrid compound having urethane (urea) group, acryl group and silica, dispersity of particle, visible light transmittance and haze were improved. We used the measurement kit and sunlamp for measuring heat-shielding property and confirmed that the internal temperature of the measurement kit using heat-shield film was lower more than $4.8^{\circ}C$ in comparison with using PET film for itself.