• Textile Coloration and Finishing
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• v.17 no.3 s.82
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• pp.26-33
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• 2005

EVA microsphere was prepared by a thermally induced phase separation. EVAL microsphere was made by a saponification on sheath of EVA microsphere. And microcapsule with EVA core-PU shell structure was synthesized by interfacial polymerization using diisocyanates with PEG in gelatin aqueous solution as the stabilizing agent. The effects of chemical structure of diisocyanate on the average particle size and distribution, morphology, color strength and friction fastness of core-shell particles were investigated to design microcapsule. The friction fastness of the fabrics printed with EVA core-PU shell microcapsules had the 4-5 grade.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.660-663
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• 2004

Recently in the automotive industries, light and high quality material is strongly required because of emissions regulation issues. In the electromagnetic stirring process, it has many merits that are the exact control ability about material processing and a good point of the protection of environment. In this paper, the morphology of the change of primary Al phase in A356 alloy by electro magnetic stirrer was investigated to obtain the globular structure. The parameters are the current, stirring time, pouring temperature and cooling rate of different wall thickness; 5mm, 15mm, 25mm respectively. By proper selection of the processing parameters, globular primary particles can be obtained by electromagnetic stirrer.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.261-264
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• 2007

In this study, the consolidation and casting processes of fine Si powders, by-products of making high purity Poly-Si rods in the current method, were systematically investigated for use as economical solar-grade feedstock. Morphology, size, and contamination type of the poly-Si fine powders were inspected by combined analysis of SEM, particle size analyzer, and FT-IR. Poly-Si powder compacts were tried to fabricate by a consolidation process without a binding agent and then their density ratio and strength were evaluated. Finally, the electrical resistivity of the specimens prepared by an electromagnetic casting method was examined for purity assessment.

• Tribology and Lubricants
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• v.14 no.4
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• pp.79-87
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• 1998

Morphological analysis of wear particles in the lubricating oil is a very effective and versatile means of lubricant analysis for machine condition monitoring and fault diagnosis. The prospects for determining quantitative information about wear particle morphology have been considerably enhanced by recent developments reported in the application of image processing and analysis techniques. This study was undertaken to investigate the influence of oiliness agent and extreme pressure agent on the shape of wear particles. The wear test was performed under different experimental conditions with stearic acid, dibenzyl disulfide(DBDS) and tricresol phosphate(TCP) in paraffinic base oil. Wear particles characteristics were described using four shape parameters, namely 50% volumetric diameter, aspect, roundness and reflectivity. The results showed that the four shape parameters of wear particles depend on a kind of the additives. This analysis of wear debris with computer image processing techniques is sufficient to distinguish some types of wear debris. The wear volume of three kinds of the specimens are affected by the additives with boundary films.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.433-437
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• 2006

Pt/Nafion self-humidifying membranes for Polymer Electrolyte Membrane Fuel Cell(PEMFC) were synthesized via supercritical-impregnation methods. The Nafion 112 membranes were impregnated with Pt(II)$(acetylacetonate)_2$ from a supercritical carbon dioxide $(scCO_2)$ solution at $80^{\circ}C$ and 30MPa. After the impregnation, the pressure decreased slowly by releasing $CO_2$. And the Pt-impregnated Nafion membrane was converted Pt deposited Nafion membrane by reducing agent, sodium borohydride $(NaBH_4)$ with various concentrations under $50^{\circ}C$ and 2 hours. The prepared Pt-impregnated Nafion (Pt/Nafion) composite membrane were investigated by Electron Prove Micro analysis (EPMA) and X-rat Diffraction analysis (XRD) which showed distribution of Pt particle and Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) a which revealed morphology of surface of Pt/Nafion composite membrane. The performance of the Pt/Nafion 112 membranes was examined in PEMFC as aself-humidifyin membranes using purpose-built equipment.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.408-412
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• 2005

Porous layered carbon was prepared by interlayer pyrolysis of pyrolysis fuel oil (PFO) using magadiite template and successive dissolution of template. Particle morphology was plate type with d-spacing of approximately 0.7 nm and it had constant interlayer space. Specific surface area was $147{\sim}385m^2/g$ depending upon template type, mixing ratios and pyrolysis time.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.68-73
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• 2005

Porous layered carbon was prepared by interlayer pyrolysis of pyrolysis fuel oil (PFO) using layered silicate template and successive dissolution of template. Particle morphology was plate type with d-spacing of 0.78~0.82 nm and constant interlayer space. Specific surface area was $30{\sim}576m^2/g$ depending upon template type, mixing ratios, pyrolysis temperature and pyrolysis time.

• Journal of Powder Materials
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• v.5 no.2
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• pp.133-138
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• 1998

The effect of $\beta$-$Si_3N_4$ seeding on microstructural development of silicon nitride based materials has been investigated. In particular, to observe more distinctly the abnormal grain growth in pressureless sintering, fine $\alpha$-$Si_3N_4$(mean particle size: 0.26 ${\mu}m$) powder classified by sedimentation method was used. It was possible to prepare silicon nitride with abnormally grown grains under low nitrogen pressure of 1 atm thanks to the heterogeneous nucleation on $Si_3N_4$ seed particles. The size and morphology of silicon nitride grains were strongly influenced by the presence of $\beta$-$Si_3N_4$ seed and overall chemical composition. For specimens with initially low $\beta$-content, the large grains grew without a significant impingement by other large grains. On the contrary, for specimens with initially high $\beta$-content, steric hindrance was effective. The resulting microstructure was less inhomogeneous and characterized by unimodal grain size distribution.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.385-393
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• 2009

Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of ${SO_4}^{2-}$ in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to $1050^{\circ}C$. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1060-1062
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• 2002

Spherical and dense BAM phosphor particles were prepared by spray pyrolysis. The key idea of dense BAM particles is to lead gelation in droplets, which was successfully achieved by using the aluminum polycation as the precursor solution for the spray pyrolysis. The BAM phosphor particles prepared by spraying the aluminum polycation solution have completely spherical shape and dense structure. When directly applied to make phosphor film on the glass by the screen-printing method, the prepared spherical BAM phosphor particles showed better packing density and surface morphology than that of commercial one, which has irregular shape and large particle size. It was also found that the thermal degradation in the photoluminescence intensity for dense and spherical BAM particles was less than that of commercial one.