• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.2
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• pp.46-56
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• 2014

The aim of this reviews is to introduce the information concerning design of the UV-curable jet ink composition in order to provide a good adhesive property on non-porous surface. In order to clarify the viscosity dependence of flying speed for the UV curable jet ink, rheological analysis and observation of the flying state of the ink were carried out. The relationship between ink formulas and adhesive property on non-porous surface was investigated. It was examined the adhesive property of radical polymerization type UV curable jet ink included hydrogen abstraction type photo-initiator, it was expected that the strong adhesive strength can be obtained between the ink and non-porous surface in this study. UV curable jet ink with a slight amount of water was prepared. Optimum ratio of the cationic polymerization type UV curable jet ink shows an adequate adhesive strength towards two kinds of non-porous surface such as glass, poly(vinyl chloride) when tests were conducted on the ink jet-printing test machine.

• Tribology and Lubricants
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• v.1 no.1
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• pp.88-101
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• 1985

There is a certain relation between the performance characteristics of the porous metal bearing and the porosity. Since the relation is not explicit, author tried to investigate it by numerical analysis and experiment. The analysis and experiment show that the load carrying capacity decreases as porosity increases while attitude angle and friction parameter increase as porosity increases.

• Solar Energy
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• v.15 no.1
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• pp.39-51
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• 1995

A numerical scheme based on a coordinate transform into stream function-velocity potential is proposed to solve heat and momentum transfer in porous media with phase change. A significant simplification of both computational domain and governing equations can be achieved by the transform. The dispersion term in the flow through porous media, which is important at the phase change interface, can be successfully incorporated into the numerical scheme without introducing any further computational complications.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.2
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• pp.78-82
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• 2023

The oxygen evolution reaction (OER) is the primary challenge in renewable energy storage technologies, specifically electrochemical water splitting for hydrogen generation. We report effects of Mo doping into Ni layered double hydroxide (Ni-LDH) microcrystal on electrocatalytic activities. In this study, Mo doped Ni-LDH were grown on three-dimensional porous nicekl foam (NF) by a facile solvothermal method. Homogeneous LDH structure on the NF was clearly observed. However, the surface microstructure of the nickel foam began to be irregular and collapsed when Mo precursor is doped. Electrocatalytic OER properties were analyzed by Linear sweep voltammetry (LSV) and Electrochemical impedance spectroscopy (EIS). The amount of Mo doping used in the electrocatalytic reaction was found to play a crucial role in improving catalytic activity. The optimum Mo amount introduced into the Ni LDH was discussed with respect to their OER performance.

• Journal of Powder Materials
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• v.22 no.6
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• pp.438-442
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• 2015

Porous thick film of alumina which is fabricated by freeze tape casting using a camphene-camphor-acrylate vehicle. Alumina slurry is mixed above the melting point of the camphene-camphor solvent. Upon cooling, the camphene-camphor crystallizes from the solution as particle-free dendrites, with the $Al_2O_3$ powder and acrylate liquid in the interdendritic spaces. Subsequently, the acrylate liquid is solidified by photopolymerization to offer mechanical properties for handling. The microstructure of the porous alumina film is characterized for systems with different cooling rate around the melting temperature of camphor-camphene. The structure of the dendritic porosity is compared as a function of ratio of camphene-camphor solvent and acrylate content, and $Al_2O_3$ powder volume fraction in acrylate in terms of the dendrite arm width.

• Journal of Powder Materials
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• v.25 no.1
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• pp.7-11
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• 2018

In this study, we synthesize tungsten oxide thin films by electrodeposition and characterize their electrochromic properties. Depending on the deposition modes, compact and porous tungsten oxide films are fabricated on a transparent indium tin oxide (ITO) substrate. The morphology and crystal structure of the electrodeposited tungsten oxide thin films are investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). X-ray photoelectron spectroscopy is employed to verify the chemical composition and the oxidation state of the films. Compared to the compact tungsten oxides, the porous films show superior electrochemical activities with higher reversibility during electrochemical reactions. Furthermore, they exhibit very high color contrast (97.0%) and switching speed (3.1 and 3.2 s). The outstanding electrochromic performances of the porous tungsten oxide thin films are mainly attributed to the porous structure, which facilitates ion intercalation/deintercalation during electrochemical reactions.

• Current Photovoltaic Research
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• v.3 no.3
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• pp.85-90
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• 2015

Two-step processes for preparing $Cu(In,Ga)Se_2$ absorber layers consist of precursor layer formation and subsequent annealing in a Se-containing atmosphere. Among the various deposition methods for precursor layer, the nonvacuum (wet) processes have been spotlighted as alternatives to vacuum-based methods due to their potential to realize low-cost, scalable PV devices. However, due to its porous nature, the precursor layer deposited on Mo substrate by nonvacuum methods often suffers from thick $MoSe_2$ formation during selenization under a high Se vapor pressure. On the contrary, selenization under a low Se pressure to avoid $MoSe_2$ formation typically leads to low crystal quality of absorber films. Although TiN has been reported as a diffusion barrier against Se, the additional sputtering to deposit TiN layer may induce the complexity of fabrication process and nullify the advantages of nonvacuum deposition of absorber film. In this work, Mo oxide layers via thermal oxidation of Mo substrate have been explored as an alternative diffusion barrier. The morphology and phase evolution was examined as a function of oxidation temperature. The resulting Mo/Mo oxides double layers were employed as a back contact electrode for $CuInSe_2$ solar cells and were found to effectively suppress the formation of $MoSe_2$ layer.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.241-248
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• 2003

We controlled the amount of Y$_2$O$_3$additives, 8 mol% and 10 mol%, and the type of carbon pore former, activated carbon and carbon black, to improve the strength of porous NiO-YSZ anode materials for solid oxide fuel ceil. The 3-point flexural strength, porosity and electrical conductivity were evaluated. As a result, the strength of anode materials with the addition of carbon black was markedly improved. The strength of NiO-10 mol%YSZ sintered at relatively higher temperature was higher than that of NiO-8 mol%YSZ materials. The electrical conductivity of NiO-10 mol%YSZ with carbon black was evaluated as much as 10$^2$∼10$^3$S/cm at 700$^{\circ}C$∼1000$^{\circ}C$ in reducing atmosphere.

• Journal of the Korean Ceramic Society
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• v.45 no.10
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• pp.579-583
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• 2008

A porous $Al_2O_3$, scaffold coated with tricalcium phosphate(TCP) was fabricated by replica method using polyurethane(PU) foam as a fugitive material. Successive coatings of $Al_2O_3$ and hydroxyapatite(HAp) were applied via dip coating onto polyurethane foam, which has a slender and well interconnected network. A porous structure was obtained after sequentially burning out the foam and then sintering at $1500^{\circ}C$. The HAp phase was changed to TCP phase at high temperature. The scaffold showed excellent interconnected porosity with pore sizes ranging from $300{\sim}700{\mu}m$ in diameter. The inherent well interconnected structural feature of PU foam remained intact in the fabricated porous scaffold, where the PU foam material was entirely replaced by $Al_2O_3$ and TCP through a consecutive layering process. Thickness of the $Al_2O_3$ base and the TCP coating was about $7{\sim}10{\mu}m$ each. The TCP coating was homogeneously dispersed on the surface of the $Al_2O_3$ scaffold.

• Current Photovoltaic Research
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• v.8 no.2
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• pp.45-49
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• 2020

Molybdenum (Mo) thin films are widely used as back contact in copper indium diselenide (CISe) solar cells. However, despite this, there are only few published studies on the properties of Mo and characteristics of CISe solar cells formed on such Mo substrates. In this studies, we investigated the properties of sputter deposited Mo bilayer, and fabricated non-vacuum CISe solar cells using bilayer Mo substrates. The changes in surface morphology and electrical resistivity were traced by varying the gas pressure during deposition of the bottom Mo layer. In porous surface structure, it was confirmed that the electrical resistivity of Mo bilayer was increased as the amount of oxygen bonded to the Mo atoms increased. The resulting solar cell characteristics vary as the bottom Mo layer deposition pressure, and the maximum solar cell efficiency was achieved when the bottom layer was deposited at 7 mTorr with a thickness of 100 nm and the top layer deposited at 3 mTorr with a thickness of 400 nm.