• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.58-59
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• 2004

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.203-205
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• 2005

• Journal of the Korean Ceramic Society
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• v.55 no.3
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• pp.261-266
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• 2018

Hollow or bumpy ZnO structures with micrometer-size features have been investigated as photocatalysts for water purification due to their high surface area available for reaction with harmful organic molecules and relatively large size for easy separation after finishing the photocatalytic reaction. In this study, selective synthesis of ZnO hollow or crumpled microspheres was performed using a simple and versatile ultrasonic spray pyrolysis process with various zinc precursors. The morphologies, phases, specific surface areas, and optical properties of the microspheres were characterized using X-ray diffraction, scanning electronic microscopy, nitrogen adsorption-desorption isotherms, and UV-vis spectroscopy. In addition, the mechanism underlying the formation of different morphologies and their photocatalytic activities were systematically investigated.

• Journal of Energy Engineering
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• v.11 no.3
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• pp.269-275
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• 2002

Experimental studies are carried out to find the behavior of sulfur compounds which are evolved during high temperature pyrolysis of coals at the smelting reduction process for iron ore. Three kinds of bituminous coals, such as Hunter & Mt. Thorley (Australia), and Ensham (South Africa) are used. And forms of sulfur compound and their amounts are analyzed at the temperature ranges of 800~110$0^{\circ}C$. Then H$_2$S is the major gas, but CS$_2$ and COS are minor gases. Sulfur compounds in three coals are distributed into the volatiles (gas & tar) and coal char as the ratio of approximately 50%：50%, respectively.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.68-68
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• 2006

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.99-99
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• 2006

• Journal of the Korean Society of Combustion
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• v.16 no.4
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• pp.8-15
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• 2011

The present study investigates the combustion phenomena in a sludge incinerator using experimental and numerical method. The temperature and gas concentration were measured at 33 points during operation of the incinerator in order to assess the mixing and combustion characteristics. Numerical simulation was also carried out using a commercial CFD code. Simplified inlet conditions were introduced in oder to predict the bulk solid combustion and the diffusion of the volatile matter released by pyrolysis of sludge. The experimental results showed that the combustion process is extremely inhomogeneous. Large variations were observed in the temperature and gas concentrations in the freeboard of the incinerator due to poor mixing performance between the air and the combustibles, which is caused by massive and bulk generation of volatile matter by fast pyrolysis of sludge particles. The boundary condition of the CFD simulation was found effective in predicting the poor mixing and combustion performance of the reactor.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.871-874
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• 2014

Monodispersed carbon nanospheres (CNSs) were fabricated by a novel method and their structural properties were investigated. CNSs were prepared by the pyrolysis of nanospherical polystyrenes (PS). With the coating of $SiO_2$ shell, PS particles were effectively separated during pyrolysis process which resulted to CNSs with an average diameter of 40 nm. Moreover, CNSs could be crosslinked with each other through the bondings between the functional groups on their surfaces. Morphology of the fabricated carbon spheres and their crosslinked form were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FT-IR).

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.788-791
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• 2002

The phosphors of high luminous efficiency for PDP application must have high purity, single phase, and dense surface. In this work, the polymeric reaction was applied to preparation of spherical phosphor by aerosol pyrolysis in order to enhance mechanical and optical characteristics. The red phosphor of (Y,Gd)$BO_3$:Eu was prepared from polymeric precursor, in which citric acid and ethylene glycol were used as ion carriers, i.e monomers. For enhancing the luminescence intensity and mechanical characteristics. optimum synthesizing condition were investigated through concentration of monomers, synthetic temperature. doped activator concentrations, and annealing process. The phosphors synthesized with monomers showed quite different morphology from those without monomers. It was observed that polymeric precursor made an effect on particle formation mechanism and status of particles surface. The resultant spherical phosphors show the comparable luminescent properties to the commercial product (product by Nichia co.). Also, they were observed to have the rigid surface.

• Journal of the Korean Ceramic Society
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• v.27 no.8
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• pp.955-964
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• 1990

A new process of emulsiion-spray pyrolysis for synthesizing ceramic powders was developed and the characteristics of Al2O3-20w/o ZrO2 composite powders prepared by this method were investigated. The composite powders synthesized in this study were spherical dense particles with 0.1~0.4${\mu}{\textrm}{m}$ of diameter. As found in powders derived by the emulsion-hot kerosene drying method, all zirconia in Al2O3-20w/o ZrO2 powders heat-treated at 120$0^{\circ}C$ was in the tetragonal form at room temperature. The relative density and the fracture toughness of composites sintered at 1$650^{\circ}C$ for 4hrs were 95% and 5.2MPa.m1/2, respectively.