• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.458-464
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• 2006

The Pd-Ni-Ag alloy composite membrane using modified porous stainless steel (PSS) as a substrate was prepared by a electroless plating technique. In this work, we have introduced the intermediate layer between Pd-based alloy and a metal substrate. As an intermediate layer, the mixtures of nickel powder and inorganic sol such as $SiO_{2}$ sol, $Al_{2}O_{3}$ sol, and $TiO_{2}$ sol were used. The intermediate layers were coated onto a PSS substrate according to various membrane preparation conditions and then $N_{2}$ fluxes through the membranes with different intermediate layers were measured. The surface morphology of the intermediate layer in the mixture of nickel powder and inorganic sol was analyzed using scanning electron microscope (SEM). Finally, the Pd-Ni-Ag alloy composite membrane using the support coated with the mixture of nickel powder and silica as an intermediate layer was fabricated and then the gas permeances for $H_{2}$ and $N_{2}$ through the Pd-based membrane were investigated. The selectivity of $H_2/N_2$ was infinite and the $H_{2}$ flux was $1.39{\times}10^{-2}mol/m^2{\cdot}s$ at the temperature of $500^{\circ}C$ and trans-membrane pressure difference of 1 bar.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.79-79
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• 2007

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.168-174
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• 2008

This study is focused on the antimicrobial activity of cyanobacteria Microcystis aeruginosa by the reduction and oxidation reaction of copper and zinc alloy metal fiber filter. Cu/Zn ion is easily makes radicals with molecular hydroperoxide. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper and zinc alloy metal fiber is detected in the cyanobacteria solution as 0.5 ppm, and that of zinc ion is 0 ppm respectively. Zinc ion is figured to form a hydroxide in the cyanobacteria solution and precipitated to form a sludge. The concentration of chlorophyll-a in the cyanobacteria solution was proved to be the index of antimicrobial level of Microcystis aeruginosa.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.69-73
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• 2009

Copper alloy metal fiber was incorporated into the conventional water-soluble metal working fluids to increase the antimicrobial activity. Fluid treated by copper alloy metal fiber is shown that bacteria is disappeared whereas that untreated metal fiber is increased bacteria as increasing the life time. When the electrochemical potential of Cu/Zn ion is -268mV, radicals with molecular oxygen are easily made. Especially, hydroperoxide radical shows strong toxicity to the strains, leading to the conformational change of plasma membrane. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.528-535
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• 2017

Fuel cells have been spotlighted in the world for being highly efficient and environmentally friendly. A hydrogen which is the fuel of fuel cell can be obtained from a number of sources. Hydrogen source for operating the polymer electrolyte membrane fuel cell(PEMFC) in the current underwater environment, such as a submarine and unmanned underwater vehicles are currently from the metal hydride cylinder. However, metal hydride has many limitations for using hydrogen carrier, such as large volume, long charging time, limited storage capacity. To solve these problems, we suggest diesel reformer for hydrogen supply source. Diesel fuel has many advantages, such as high hydrogen storage density, easy to transport and also well-infra structure. However, conventional diesel reforming system for PEMFC requires a large volume and complex CO removal system for lowering the CO level to less than 10 ppm. In addition, because the preferential oxidation(PROX) reaction is the strong exothermic reaction, cooling load is required. By changing this PROX reactor to hydrogen separation membrane, the problem from PROX reactor can be solved. This is because hydrogen separation membranes are small and permeable to pure hydrogen. In this study, we conducted the pressurized diesel reforming and water-gas shift reaction experiment for the hydrogen separation membrane application. Then, the hydrogen permeation experiments were performed using a Pd alloy membrane for the reformate gas.

• Membrane Journal
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• v.32 no.2
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• pp.116-125
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• 2022

In this experiment, an α-Al₂O₃ ceramic hollow fiber was used as a support, and a hydrogen membrane plated with Pd and Pd-Ag was manufactured through electroless plating. The Pd-Ag membrane was annealed at 500℃ for 10 h to form an alloy of Pd and Ag. It was confirmed that it became a Pd-Ag alloy through EDS (Energy Dispersive X-ray Spectroscopy) analysis. Also, the thickness of the Pd, Pd-Ag plating layer was measured to be about 8.98 and 9.29 ㎛ through SEM (Scanning Electron Microscope) analysis respectively. Hydrogen permeation experiment was performed using the H₂ gas and mixed gas (H₂ and N₂) in the range of 350~450℃ and 1-4 bar using the prepared hydrogen membrane. Under the H₂ gas condition, the Pd and Pd-Ag membrane has a flux of up to 21.85 and 13.76 mL/cm²·min and also separation factors of 1216 and 361 were obtained in the mixed gas at 450℃ and 4 bar conditions respectively.

• Journal of the Korean institute of surface engineering
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• v.46 no.6
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• pp.248-257
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• 2013

It is generally recognized that thin Pd-Cu alloy films fabricated by sputtering show a wide range of microstructures and properties, both of which are highly dependent on the sputtering conditions. In view of this, the present study aims to investigate the relationship between the performance of hydrogen separation membranes and the microstructure of Pd alloy films depending on sputtering deposition conditions such as substrate temperature, working pressure, and DC power. We fabricated thin and dense Pd-Cu alloy membranes by the micro-polishing of porous Ni support, an advanced Pd-Cu sputtered multi-deposition under the conditions of high substrate temperature / low working pressure / high DC power, and a followed by Cu-reflow heat-treatment. The result of a hydrogen permeation test indicated that the selectivity for $H_2/N_2$ was infinite because of the void-free and dense surface of the Pd alloy membranes, and the hydrogen permeability was 10.5 $ml{\cdot}cm^{-2}{\cdot}min^{-1}{\cdot}atm^{-1}$ for a 6 ${\mu}m$ membrane thickness.

• Journal of the Korean institute of surface engineering
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• v.48 no.1
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• pp.11-22
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• 2015

Pd alloy hydrogen membranes for hydrogen purification and separation need thermal stability at high temperature for commercial applications. Intermetallic diffusion between the Pd alloy film and the porous metal support gives rise to serious problems in long-term stability of Pd alloy membranes. Ceramic barriers are widely used to prevent the intermetallic diffusion from the porous metal support. However, these layers result in poor adhesion at the interface between film and barrier because of the fundamentally poor chemical affinity and a large thermal stress. In this study, we developed Pd alloy membranes having a dense microstructure and saturated composition on modified metal supports by advanced DC magnetron sputtering and heat treatment for enhanced thermal stability. Experimental results showed that Pd-Cu and Pd-Ag alloy membranes had considerably enhanced long-term stability owing to stable, dense alloy film microstructure and saturated composition, effective diffusion barrier, and good adhesive interface layer.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.50-57
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• 1998

The leak before break(LBB) concept is generalized on the design of LNG tanks, pressure vessels and nuclear reactor in that any leakage of containment, in whatever amount, will not result in catastropic failure. For this purpose it is necessary to determine the surface crack shape, the opening displacement and the risk of catastropic brittle fracture when it becomes a through crack. In this study the crack propagation behavior of surface flaws and the crack opening displacement of through cracks under combined membrane and bending stresses were investigated with fatigue tests and fracture toughness test of aluminium alloy A5083-O. And fracture mechanics analysis of the crack opening displacement of through cracks were made in order to develop a new model expressing the behaviors of COD under combined membrane and bending stresses.

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.05a
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• pp.11.1-11.1
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• 2008