• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11b
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• pp.300-315
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• 2005

Recently plasma surface-cleaning or surface-etching techniques have been focused in the respect of decontamination of spent or used nuclear parts and equipment. In this study decontamination rate of metallic cobalt surface was experimentally investigated via its surface etching rate with a $CF_4-O_2$ mixed gas plasma and metallic surface wastes of cobalt oxides were simulated and decontaminated with $NF_3$ - Ar mixed gas plasma. Experimental results revealed that a mixed etchant gas with about $80{\%}\;CF_4-20{\%}\;O_2$ gives the highest reaction rate of cobalt disk and the rate reaches with a negative 300 DC bias voltage up to $0.43\;{\mu}m$/min at $380^{\circ}C$ and $20{\%}\;NF_3-80\%$ Ar mixed gas gives $0.2\;{\mu}m$/min of reaction rate of cobalt oxide film.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1536-1539
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• 1994

The influence due to metallic particle contaminated on spacer surface is remarkable in the decreasing of dielectric strength in $SF_6$ GIS. In relation with this problem, We studied, AC flash-over voltage characteristics and breakdown mechanism are investigated under metallic particle initiated condition in $SF_6$ gas by varying the particle position, particle shape with a plane-plane electrode. The main results arc as follows 1. The small amount of the metallic particle in the gap do not make flash-over voltage to be influence, but the significant decrease of th flash-overed voltage is result in case of the big and long size of the metallic paraticle. 2. Influence of the flash-over voltage are lowest in the mid and are highest in the electrode of metallic particle position. 3. In case of the initiated metallie particle, The more the pressure are high, the more the recluced ratio of flash-over voltage are high. 4. The metallic particle shape which results in the reduced flash-over voltage forced the critical pressure to move in to the region of low pressure. 5. The existance of the metallic particle on the upper electrode side and high pressure make the decreasing ratio of flash-over voltage bigger than that of the ground side electrode.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.143-147
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• 2016

Characteristics of the conventional gold (Au) surface plasmon resonance (SPR) chip, bi-metallic(Au/silver (Ag)) SPR chip, and tri-metallic(Au/Ag/Au) SPR chip were investigated and compared in the intensity measurement mode for the enhancement of SPR image sensor reactivity. Reflectance curves of the Au, bi- and tri-metallic SPR chips were acquired in phosphate-buffered saline (PBS) solution and were compared. The line width of the reflectance curve of the bi-metallic chip was the narrowest among the three different types of the chips. Also, the tangential slope of the bi-metallic chip was steeper than those of the other chips. Various concentrations of bovine serum albumin (BSA) were utilized in the SPR experiment. As a result, among the above three chips reflectance variation value of the bi-metallic chip was the largest.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.420-423
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• 2002

In this paper the characteristics of surface flashover for high temperature superconducting transformer(HTS) was discussed. The transformer, will be developed in the shell type with double pancake coil, isn't developed yet in the world. We conducted experiment of surface flashover that could occur in the windings of the transformer. First, we distinguished the surface flashover with electrode alignment into two type, such as parallel and vertical, and then compared with each characteristics of surface flashover. And the surface flashover with metallic particle was tested, it was also affected by the particle position. .

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.121-128
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• 2006

The interaction between adherent molecules and gas molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantity and gas molecular collisions because the industrial oil has too complex structures of fatty acid. Effects of adherent quantity, gas temperature, surface temperature and adhesion strength for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on the surface temperature shown in the experimental results.

• Journal of Magnetics
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• v.12 no.3
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• pp.97-102
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• 2007

We have investigated the electronic structures and magnetism of a full Heusler alloy $Co_2CrGa(001)$ surface by using the all-electron full-potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation (GGA). We considered two types of different terminations: the Co-terminated (Co-Term) and the CrGa-terminated (CrGa-Term) surfaces. From the calculated layer-projected density of states (LDOS), we found that the surface of the CrGa-Term shows nearly half-metallic character while that of the Co-Term is far from the half-metallic. For the Co-Term, the surface Co atom moves down to the bulk region by $0.05{\AA}A$, while the subsurface Cr and Ga atoms move up to the surface layer by 0.05 and $0.01{\AA}$, respectively. For the CrGa-Term, there is a large inward relaxation of the surface Ga atom $(0.07{\AA})$, but the relaxation of the surface Cr atom is very small $(0.01{\AA})$. The relaxations affect not much to the overall shapes of DOS for both terminations, but make the surface states of the surface Cr and Ga atoms for the CrGa-Term shift to higher energy that enhances the nearly half-metallic character of the CrGa-Term. The magnetic moments of the surface $Cr(2.98{\mu}_B)$ in the CrGa-Term and the surface $Co(1.17{\mu}_B)$ in the Co-Term were much increased compared to those of the inner-layers $(1.79\;and\;0.77{\mu}_B)$, respectively, while that of the subsurface Cr atom in the Co-Term was decreased to $1.19{\mu}_B$.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.985-986
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• 2006

Principal peculiarities of technology for applying coatings of metallic powders on internal surfaces of hollow cylindrical parts by centrifugal method with induction heating from internal surface of part are examined. It is shown that most effective checking and regulating method of sintered powder layer is monitoring the high-frequency current generator power upon contactless pickup indications of external surface temperature of rotating part.

• Journal of the Korean institute of surface engineering
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• v.30 no.5
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• pp.347-354
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• 1997

Composite plating is a method of co-depositing fine particles of metallic, non-metallic compound or polymers in the plated layer to improve material properties such as were-resistance, lubrication, or corrosion resistance. Graded Ni-Sic composite coating were produced in this research. Prior to produce Graded Ni-SiC composite coatings, effects of particle size, particle content, pH of electrolyte, temperature, current density, stirring rate on the amount of SiC deposited in the Ni layer were investigated. By manipulating current density and plating time properties of these coating were evaluated by micro-indentation hardness test.

• Journal of the Korean institute of surface engineering
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• v.7 no.1
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• pp.17-34
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• 1974

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1983-1987
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• 2008

This study demonstrates the electrochemical conversion of the synthetic procedure of monolayer-protected clusters using a thin toluene layer over an edge plane pyrolytic graphite electrode. A thin toluene layer with a thickness of 0.31 mm was coated over the electrode and an immiscible liquid/liquid water/toluene interface was introduced. The transfer of the tetrachloroaurate ($AuCl_4^-$) ions into the toluene layer interposed between the aqueous solution and the electrode surface was electrochemically monitored. The $AuCl_4^-$ ions initially could not move through into the toluene layer, showing no reduction wave, but, in the presence of the phase transfer reagent, tetraoctylammonium bromide (TOABr), a cathodic wave at 0.23 V vs. Ag/AgCl was observed, indicating the reduction of the transferred $AuCl_4^-$ ions in the toluene layer. In the presence of dodecanethiol together with TOABr, a self-assembled monolayer was formed over the electro-deposited metallic gold surface. The E-SEM image of the surface indicates the formation of a highly porous metallic gold surface, rather than individual nanoparticles, over the EPG electrode.