• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.79-83
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• 1998

Plasma display panel is a potential candidate for HDTV, due to the fact hat the expansion of screen size is much easier using thick film technology. In this study, transparent dielectric materials using lead borosilicate glasses is developed, which satisfy the requirements of dielectrics for PDP. Paste is made of this glass composition. The paste has thixotropic behavior suitable for screen printing. The paste shows more thixotropic behavior as the particle size decrease. After firing, cross sectional area was analyzed by SEM. The void of fired thick film was removed using bimodal particle system. The dielectric showed good adhesion characteristics.

• The Korean Journal of Ceramics
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• v.2 no.2
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• pp.63-69
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• 1996

Barium titanyl oxalates, strontium titanyl oxalates and calcium zirconyl oxalates were prepared with variation of solution concentration and method of adding mixed metal ion solution into oxalic acid. Then they were aged in distilled water, ethanol or methanol, respectively. Barium titanyl oxalates and calcium zironyl oxalates were grown in water and strontium titanyl oxalates were groun in both water and methanol. They were supposed to be grown through the solutionl and reprecipitation mechanism. Nonuniform dispersion of particles in liquid phase is thought to cause abnormal particle growth.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.466-467
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• 2006

The anatase particle was facetted at the free surface and a neck formation between the anatase particles prior to the phase transformation occured. This resulted in the severe lattice distortion at the region of the interface near the neck and this can act as the nucleation sites for the phase transformation. The grain growth of rutile particles after the phase transformation grew very fast by the sweeping phenomena of grain boundary. Therfore, It leaded to the microstructure without the rutile phase located in anatase particle.

• Journal of the Korean Ceramic Society
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• v.36 no.11
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• pp.1150-1155
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• 1999

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.10a
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• pp.126-126
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• 2003

• Korean Journal of Materials Research
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• v.21 no.3
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• pp.156-160
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• 2011

FePt nanoparticles suspension was synthesized by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine. FePt nanoparticles were coated on a substrate by convective assembly from the suspension. To prevent the coalescence during the annealing of FePt nanoparticles double convective coatings were tried. First convective coating was for silica particle assembly on a silicon substrate and second one was for FePt nanoparticles on the previously coated silica layers. It was observed by scanning electron microscopy (SEM) that FePt nanoparticles were dispersed on the silica particle surface. After annealing at $700^{\circ}C$ for 30 minutes under nitrogen atmosphere, FePt nanoparticles on silica particles were maintained in a dispersed state with slight increase of particle size. On the contrary, FePt nanoparticles that were directly coated on silicon substrate showed severe particle growth after annealing due to the close-packing of nanoparticles during assembly. The size variation during annealing was also verified by X-ray diffractometer (XRD). It was suggested that pre-coating, which offered solvent flux oppose to the capillary force between FePt nanoparticles, was an effective method to prevent coalescence of nano-sized particles under high temperature annealing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1139-1150
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• 1999

The evolution of silica aggregate particles in coflow diffusion flames has been studied experimentally using light scattering and thermophoretic sampling techniques. The measurements of scattering cross section from $90^{\circ}$ light scattering have been utilized to calculate the aggregate number density and volume fraction using with combination of measuring the particle size and morphology through the localized sampling and a TEM image analysis. Aggregate or particle number densities and volume fractions were calculated using Rayleigh-Debye-Gans and Mie theory for fractal aggregates and spherical particles, respectively. Of particular interests are the effects of flame temperature on the evolution of silica aggregate particles. As the flow rate of $H_2$ increases, the primary particle diameters of silica aggregates have been first decreased, but, further increase of $H_2$ flow rate causes the diameter of primary particles to increase and for sufficiently larger flow rates, the fractal aggregates finally become spherical particles. The variation of primary particle size along the upward jet centerline and the effect of burner configuration have also been studied.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.370-375
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• 2018

In this study, we have applied fractional precipitation with hydrophilic polymer in order to decrease the particle size of the (+)-dihydromyricetin from plant materials. When compared with the case where no hydrophilic polymer was employed, the addition of hydrophilic polymer in fractional precipitation resulted in a considerable decrease in the size of the (+)-dihydromyricetin precipitate. Among the polymers used, HPMC 2910 was the most effective for inhibition of precipitate growth. A polymer concentration of 0.1% (w/v) yielded the smallest particle size. The particle size was reduced by ~40% compared to control. In addition, the precipitate size was inversely correlated with the absolute value of the zeta potential of the suspension with polymer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.6
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• pp.365-372
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• 2016

Using the computational fluid dynamics (CFD) technique, we simulated the fluid flow in a Taylor reactor considering the aggregation and breakage of particles. We calculated the population balance equation (PBE) to determine the particle-size distribution by implementing the quadrature method-of-moment (QMOM). It was used that six moments for an initial moments, the sum of Brownian kernel and turbulent kernel for aggregation kernel, and power-law kernel for breakage kernel. We predicted the final mean particle size when the particle had various initial volume fraction values. The result showed that the mean particle size and initial growth rate increased as the initial volume fraction of the particle increased.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.8
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• pp.1583-1594
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• 1992

A numerical calculation on the flame structure and soot particle distribution in a coannular laminar diffusion flame was performed. Flame analysis model utilized basically flame sheet concepts, Shvab-Zel'dovich assumption, and one step overall irreversible reaction. It was also considered the variation of thermodynamics and transport properties, and the stagnation enthalpy was used for solving temperature field. Radiation was taken into account, since it has been found to be important in determining the flame temperature in sooty flames. For soot particle analysis, we adopted the coagulation, suface condensation, and the oxidation model in addition to tesner's two-step formation model. Equations for primary soot particle excluding the agglomeration process were solved. Based on the results, the regions of soot generation, growth, and oxidation in the flame have been observed and radiation strongly influenced flame temperature and soot distribution.