• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.336-337
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• 2017

• Journal of the Korean Ceramic Society
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• v.49 no.3
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• pp.247-252
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• 2012

Crystal structure and chemical compositions of Plasma electrolytic oxidized layer of A-1100, A-2024, A-5052, A-6061, A-6063, A-7075, ACD-7B and ACD-12 were investigated. The electrolyte for plasma electrolytic oxidation was mixture of distilled water, $Na_2P_2O_7$, Cu, Cr metal salts and KOH. ${\eta}$-Alumina, as well as ${\alpha}$-alumina, was main crystal phase. Another crystals such as $(Al_{0.948}Cr_{0.052})_2O_3$ and $(Al_{0.9}Cr_{0.1})_2O_3$ were also formed in the oxide layer. It was thought that the effect of electrolyte compositions on the physical properties and crystal system of PEO layers was greater than the effect of Al alloy composition variation.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.556-561
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• 2012

In this study, the effect of properties of gas diffusion layer (GDL) on the performance of polymer electrolyte membrane fuel cell (PEMFC) was investigated using the numerical simulation. The multi-phase mixture ($M^2$) model was used to calculate liquid water saturation and oxygen concentration in GDL. GDL properties, which were contact angle, porosity, gas permeability and thickness, were changed to investigate the effect of GDL properties on the performance of PEMFC. The results demonstrated that performance of PEMFC was increased with increasing contact angle and porosity of GDL, but decreased with increasing thickness of GDL. The liquid water saturation was decreased but oxygen concentration was increased at the GDL-catalyst layer interface, because the mass transfer resistance decreased as the porosity and contact angle increased. On the other hands, as the thickness of GDL increased, pathway for liquid water and oxygen gas became longer, and then mass transfer resistance increased. For this reason, performance of PEMFC decreased with increasing thickness of GDL.

• Membrane Journal
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• v.21 no.3
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• pp.213-221
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• 2011

Using poly(ethylene oxide) (PEO) as a polymer host, poly(ethylene glycol) (PEG) as a plasticizer, potassium iodide and iodine as sources of $I^-/I_3^-$, polymer electrolyte membranes were prepared. Based on the polymer electrolytes, solid-state dye-sensitized solar cell (DSSC)s were fabricated. The content of PEG in the electrolyte was controlled to be 95%. The mole number of KI per 1 mole of EO ([KI]/[EO] ratio) in the electrolyte was changed to be 0.022, 0.044, 0.066 and 0.088. The electrolyte membrane showed wax phase in ambient temperature. The ionic conductivity increased with increasing KI content to reach the maximum value at which [KI]/[EO] ratio is 0.066. After the maximum value, the ionic conductivity decreased with increasing KI content. In the case of DSSC, the Voc decreased continuously with increasing KI content in the polymeric electrolyte membrane. The $J_{SC}$ increased with increasing KI content to show maximum value at which [KI]/[EO] ratio is 0.044. In the higher KI content region, $J_{SC}$ value decreased with increasing KI content.

• Membrane Journal
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• v.32 no.1
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• pp.43-49
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• 2022

Solid-state supercapacitors with high safety and robust mechanical properties are attracting global attention as next-generation energy storage devices. As an electrode of a supercapacitor, an economical carbon-based electrode is widely used. However, when an aqueous electrolyte is introduced, the charge transfer resistance increases because the interfacial contact between the hydrophobic electrode surface and aqueous electrolyte is not good. In this regard, we propose a method to obtain higher electrochemical performance based on improved interfacial properties by treating the electrode surface with oxygen plasma. The surface hydrophilization induced by the enriched oxygen functionalities was confirmed by the contact angle measurement. As a result, the degree of hydrophilization was easily adjusted by controlling the power and duration of the oxygen plasma treatment. As the electrolyte of the supercapacitor, PVA/H₃PO₄, which is a typical solid-state aqueous electrolyte, was used. Free-standing membranes of PVA/H₃PO₄ electrolyte were prepared and then pressed onto the electrode. The optimal condition was to perform oxygen plasma treatment for 5 seconds with a low power of 15 W, and the energy density of the supercapacitor increased by about 8%.

• Nuclear Engineering and Technology
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• v.18 no.3
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• pp.194-199
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• 1986

The behavior of micro amount of Am in aqueous solution were investigated with centrifugation method as a function of pH. In the studies described here, equilibration times were extended to 2-3 weeks to know the aging effect in radiocolloid formation. Also, the effect of the addition of foreign materials, e. g. silica gel and Fe$^{3+}$ were examined as well as the effect of presence of concentrated electrolyte. In the results, Am appeared to be rapidly adsorbed on to impurity particles for pH < 6 and probably on the container walls by an ionic sorption process. The addition of foreign material increased the fraction of Am while the addition of concentrated electrolyte hindered the process. For pH > 7 Am behaved quite differently than for pH < 6. There appeared to be rapid sorption of some Am from solution probably on the container walls followed by partial desorption that occurred over a period of 1-2 days.s.

• Journal of Surface Science and Engineering
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• v.48 no.2
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• pp.62-67
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• 2015

Nickel is a commercially important and versatile element in electroplating. The applications of nickel electroplating fall into three main categories: decorative, functional and electroforming. In decorative applications, electroplated nickel is most often applied in combination with electrodeposited chromium. Nickel is deposited on surfaces to improve corrosion and wear resistance or modify magnetic and other properties. Electroforming is electroplating applied to the fabrication of products of various kinds. Nickel is deposited onto a substrate and then removed from it to create a part made entirely of nickel. In this study, mechanical property of Ni electrodeposits in various manufacturing condition such as temperature, current density, pH and electrolyte content, was investigated to understand effect of electrolysis condition on mechanical property. Vickers hardness increased as the temperature and pH increased and current density and electrolyte content decreased and pH increased. The results were explained by cathode overvoltage and hydrogen evolution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.6
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• pp.590-596
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• 1999

The effects of additives on the Zn electrodeposition in chloride-based electrolyte were investigated using circulation cell with three electrodes system. The cathodic polarization increased with the addition of polyethylenglycol (hereafter PEG) in electrolyte. This was attributed to the adsorption of the additives on the electrode and the inhibition of migration of metal ion. The PEG, however, did not have any noticeable effect on the properties of plating solutions at the concentration used. The effect of PEG on the electrocrystallization was related to its molecular weight. With the increase of molecular weight, the cathodic polarization increased, while the surface roughness was improved with the decrease of brightness. Especially, the PEG mixed with different molecular weights was the most effective. The orientation and the type of the deposited grains were changed and refined by PEG, which resulted in the modification of deposited surface roughness and brightness.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.715-719
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• 2007

STS444 with or without $La_{0.9}Sr_{0.1}MnO_3$ (LSM)-coating was contacted to $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ (LSCF) cathode on various electrolyte materials and the polarization resistance $(R_p)$ was measured by impedance spectroscopy. By making a symmetric half-cell and contacting only one side of the cathode with the interconnect, the effect of chromium (Cr) poisoning was separated from the aging effects. When the LSCF cathode was contacted with LSM-coated STS (stainless steel), $R_p$ of LSCF was lower than that contacted with the uncoated STS. Impedance patterns measured for the working electrode (W.E.), the counter electrode (C.E.) at $600^{\circ}C$ in air were analyzed. Normalized data of net Cr effect showed that $Ce_{0.9}Gd_{0.1}O_2$ (GDC) electrolyte is more tolerant to the chromium poisoning than $La_{0.9}Sr_{0.1}Ga_{0.8}Mg_{0.2}$ (LSGM) or 8 mol% $Y_2O_3-doped$ $ZrO_2$ (YSZ) electrolytes.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.63-68
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• 1994

The Curie point annealing effects on electrophysical phenomena at the magnetized strontium ferrite(SrO$\cdot$ 6$Fe_{2}O_{3}$) ceramics electrode/10$^{-3}$M KC1 aqueous electrolyte interfaces have been studied using cyclic voltammetric, normal pulse voltammetric, chronocoulometric, and electrochemical impedance techiques. After the Curie point annealing the magnetic flux densities of the speciment was decreased from 900-1100 gauss to 1-2 gauss, i.e. demagnetized. The real component of interfacial impedance was decreased from 7280-7320 ohm to 790-830 ohm. The adsorption and the charge on the electrical double layer was increased from 0 $\mu$C to -58 $\mu$C. The Curie point annealing and the related electrical double layer effect can influence not only the electrophysical properties of the strontium ferrite ceramics electrode itself but also the electrochemical phenomena at the electrode interface. This experimental results suggest that the Curie point annealing and the related electrical double layer effect can be applied to electrochemical magnetic sensors.