• Archives of Plastic Surgery
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• v.35 no.4
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• pp.431-438
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• 2008

Purpose: The common deformity after the correction of unilateral cleft lip nasal deformity is nasal asymmetry, and it is caused by the hypoplasia of the pyriform aperture. To correct this, many procedures have been applied, but still many problems are present. Authors performed the inlay and onlay insertion of porous high density polyethylene sheet(1 mm thickness $Medpor{(R)}$ sheet) in the hypoplastic pyriform margin of cleft side and obtained satisfactory results. Methods: 11 cases were performed and the mean follow up period was 15.1 months. Their mean age was 23.6 years. Under general anesthesia, bilateral pyriform margin was exposed. $Medpor{(R)}$ sheets in "match stick" like shaped were inlay inserted, and kidney shaped were onlay inserted fixating with two 6 mm titanium screws. After the surgery, the results was evaluated by photogrammetric analysis. On the basal view, the distance from the subalare and labiale superius' to the transverse baseline connecting the both cheilions was measured from the cleft side and the non-cleft side. Then, the postoperative symmetry was assessed by obtaining the cleft side against the non-cleft side as proportion index, defined as lateral and medial upper lip contour index. Results: There were 2 infections. The cause was because the inserted implant was too long and thus protruded to the base of nasal cavity. The lateral upper lip contour index was from 95.49 to 103.27, and medial upper lip contour index was from 90.92 to 100.49, it was statistically increased, and thus the symmetry was improved. However clinically mild depression remained at nostril floor. Conclusion: Authors performed porous high density polyethylene sheet inlay and onlay insertion for the hypoplasia of the pyriform margin in unilateral cleft lip nasal deformity. It was found that depressed pyriform margin and upper lip were corrected effectively except for the nostril floor, for which an additional soft tissue augmentation would be necessary. The inlay insertion has risk of protrusion, thus the guideline of the use of artificial prosthesis should be observed strictly.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.249-252
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• 2009

Nanocrystalline ceria particles were prepared by using the ultrasonic spray pyrolysis method. The prepared ceria particles were found to be spherical and non-agglomerated by the SEM and TEM analyses. It was found that carrier gas influences the size and morphology. It was found that the air stream of carrier gas results in porous agglomerated structure of ceria abrasives, whereas solid nano-sphere can be obtained in a more oxidizing atmosphere.

• Journal of applied mathematics & informatics
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• v.31 no.5_6
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• pp.631-642
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• 2013

In this paper we reconsider the problem of steady mixed convection boundary-layer flow over a vertical flat plate studied in [6],[7] and [13]. Under favorable assumptions, we prove existence of multiple similarity solutions, we study also their asymptotic behavior. Numerical solutions are carried out using a shooting integration scheme.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.1-3
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• 1991

A novel membrane separation process for the separation of liquid mixture is Pervaporation. The term, 'pervaporation', is a combination of permeation and evaporation, and was first introduced by kober[1] in 1917. In this technique, the liquid mixture in feed is in contact with one side of a dense non-porous membrane and after diffusing through the membrane is removed from the downstream side in the vapor phase, but is usually condensed afterwards to obtain a permeate in liquid from.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.946-951
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• 1998

In order to calculate the thermal stresses of massive concrete structures in non-steady state conditions the thermal properties of the materials have to be well known. Structural materials such as concrete, rock and soil are heterogeneous, damp and porous so that measurements of their thermal properties by conventional methods would result in large errors. In this study, thermal conductivity was measured by the device, QTM-D3 which is usually used in Japan. Variables are chosen as age, water content, temperature, aggregate content, S/A ratio and type of cementitious materials. Finally a model for thermal conductivity was proposed.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1302-1308
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• 2006

The unsteady Hartmann flow of an electrically conducting, viscous, incompressible fluid bounded by two parallel non-conducting porous plates is studied with heat transfer taking the Hall effect into consideration. An external uniform magnetic field and a uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to an exponential decaying pressure gradient. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effect of the ion slip and the uniform suction and injection on both the velocity and temperature distributions is examined.

• The Pure and Applied Mathematics
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• v.13 no.1 s.31
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• pp.1-10
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• 2006

The unsteady Hartmann flow of an electrically conducting, viscous, incompressible fluid bounded by two parallel non-conducting porous plates is studied with heat transfer. An external uniform magnetic field and a uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to a constant pressure gradient. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effect of the magnetic field and the uniform suction and injection on both the velocity and temperature distributions is examined.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.409-414
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• 2008

Porous carbon electrode for electrosorption was prepared by a wet phase inversion method. Carbon slurry that was a mixture of activated carbon powder(ACP) and PVdF solution was cast directly upon a graphite sheet by means of a casting knife. Porous carbon electrodes were fabricated by immersing the cast film in pure water as a non solvent. Physical and electrochemical properties of carbon electrodes prepared with various ACP contents(50.0, 75.0, 83.3, 87.5, 90.0 wt %). From the SEM images we can verify that the electrode was porous. The average pore sizes determined for the electrodes fabricated with various ACP contents ranged from 72.7 to 86.4 nm and the size decreased as the ACP content increased. The electrochemical properties were characterized by cyclic voltammetry(CV) method. All of the voltammograms showed typical behavior of an electric double layer charging/discharging on the carbon surface. The capacitance increased with the ACP content and the values ranged from 2.18 F/cm$^2$ for 50 wt% ACP to 4.77 F/cm$^2$ for 90 wt% ACP.

• Resources Recycling
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• v.19 no.5
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• pp.31-43
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• 2010

To fabricate porous SiC candle filter for filtration facility of the IGCC system, the candle type filter preforms were fabricated by ramming and vacuum extrusion process. A commercially available ${\alpha}$-SiC powders with various particle size were used as starting raw materials, and $44\;{\mu}m$ mullite, $CaCO_3$ powder were used as non-clay based inorganic sintering additive. The candle typed preforms by ramming process and vacuum extrusion were sintered at $1400^{\circ}C$ for 2h in air atmosphere. The effect of forming method and particle size of filter matrix on porosity, density, strength (flexural and compressive strength) and microstructure of the sintered porous SiC candle tilters were investigated. The sintered porous SiC filters which were fabricated by ramming process have more higher density and strength than extruded filter in same particle size of the matrix, and its maximum density and 3-point bending strength were $2.00\;g/cm^3$ and 45 MPa, respectively. Also, corrosion test of the sintered candle filter specimens by different forming method was performed at $600^{\circ}C$ for 2400h using IGCC syngas atmosphere for estimation of long-term reliability of the candle filter matrix.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.71-79
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• 2023

In this study, we employed anionic, cationic, and nonionic surfactants for the hydrophilization of porous substrates used in the fabrication of pore-filling membranes. We investigated the extent of hydrophilization based on the type of surfactant, its concentration, and immersion time. Furthermore, we used the hydrophilized substrates to produce pore-filling anion exchange membranes and compared their ion conductivity to determine the optimal hydrophilization conditions. For the ionic surfactants used in this study, we observed that hydrophilization progressed rapidly from the beginning of immersion when the applied concentration was 3.0 wt%, compared to lower concentrations (0.05, 0.5, and 1.0 wt%). In contrast, for the relatively larger molecular weight non-ionic surfactants, smooth hydrophilization was not observed. There was no apparent correlation between the degree of hydrophilization and the ion conductivity of the anion exchange membrane. This discrepancy suggests that an excessive hydrophilization process during the treatment of porous substrates leads to excessive adsorption of the surfactant on the sparse surfaces of the porous substrate, resulting in a significant reduction in porosity and subsequently decreasing the content of polymer electrolyte capable of ion exchange, thereby greatly increasing the electrical resistance of the membrane.