• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.337-337
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• 2004

As one of researches for the P ＆ T purposes, a basic experiment on the recovery of actinide elements from the mixture with rare earth elements by means of electrorefining using a liquid cadmium cathode in the LiCl-KC1 eutectic melt was carried out. In order to examine the behaviors of electrodeposition of metal ions on a liquid electrode, recovery experiments of rare earth metals resulting from forming electrodeposits were performed by a galvanostatic electrolysis method at various current densities. A cyclic voltammetric technique was applied to determine reduction-oxidation potential of each metal element in the melt and to detect the changes of the multi component melt composition for on-line monitoring. Also, a collaboration study with RIAR was completed to test the preliminary feasibility on a recovery of actinide elements from the mixture with rare earth elements using a liquid cadmium cathode and actinide metals. Experimental results showed that the ratio of actinides to rare earths, 9: 0.5∼1 led to the rare earth content of about 5∼10 wt% in the deposit.

• 한국표면공학회지
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• 제55권3호
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• pp.180-186
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• 2022

The production of hydrogen via water electrolysis (i.e., green hydrogen) using renewable energy is key to the development of a sustainable society. However, most current electrocatalysts are based on expensive precious metals and require the use of highly purified water in the electrolyte. We demonstrated the preparation of a non-precious metal catalyst based on CuCo₂O₄ (CCO) via simple electrodeposition. Further, an optimization process for electrodeposition potential, solution concentration and electrodeposition method was develop for a catalyst-substrate integrated electrode, which indicated the highly electrocatalytic performance of the material in electrochemical tests and when applied to an anion exchange membrane water electrolyzer.

• 자원리싸이클링
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• 제25권2호
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• pp.25-32
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• 2016

개조된 사이클론식 전해조를 사용하여 황산염 용액으로부터 금속 주석으로 회수하기 위하여 주석의 전해채취 거동을 조사하였다. 실험 변수로는 유속의 영향, 전류밀도, 전해질 용액의 황산 농도 및 주석 농도 등에 대하여 실시하였다. 실험 결과 $100{\mu}m$이하 크기의 분말상 금속 주석을 얻을 수 있었다. 유속 및 전류밀도 그리고 전해액중 황산농도가 증가할수록 주석의 석출율 및 전류효율값이 증가하였다. 그러나 주석의 농도가 감소함에 따라 주석의 석출율은 증가하나, 전류효율값은 감소하였다.

• 공업화학
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• 제16권2호
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• pp.250-256
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• 2005

자동차 산업에서의 도장 외관은 아주 중요하다. 이러한 도장외관의 향상을 위해서 기본적으로 도막의 내식성과 밀착성이 해결되어야 한다. 도막의 물성의 향상을 위해서 금속의 화성피막은 매우 중요한 요소가 되고 있다. 전착도장 중 음극에서의 pH는 12 정도까지 증가하고, 이 같은 강알카리 조건에서 금속과 화성피막의 용해가 일어난다. 이 같은 현상의 화성피막과 소재사이의 결합력을 감소시키게 된다. 일반적으로 인산염 피막구조는 hopeite 및 phosphphylife 구조를 갖지만 hopeite 피막 구조보다는 phosphophyllite 피막구조가 내식성이 보다 우수하고, 양이온 전착도료에 의한 전착도장에서 강알카리화된 계면에서 피막의 알카리 용해성이 적어 내수밀착성의 향상을 보인다. Ni, Mn 등의 보조금속의 첨가는 P-ratio (phosphophyllite/ hopeite + phosphophyllite)를 증가시키므로 내수 밀착성과 내식성을 향상시키게 됨을 알 수 있었다.

• Journal of Electrochemical Science and Technology
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• 제5권4호
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• pp.115-127
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• 2014

Cd-Pb thin films were electrodeposited from a diluted chloride solution using stainless steel rotating disc electrode. The linear sweep voltammograms of the single metallic ions show that electrodeposition of these ions was mass transfer control due to the plateau observed for different rotations at concentration (50 and 200 ppm). The voltammograms of binary system elucidate that electrodeposition process always start at cathodic potential located between the potential of individual metals. Currents transients measurements, anodic linear sweep voltammetry (ALSV) and atomic force microscopy (AFM) were used to characterize the electrocryatalization process and morphology of thin films. ALSV profiles show a differentiation for the dissolution process of individual metals and binary system. Two peaks of dissolution Cd-Pb film were observed for the binary system with different metal ion concentration ratios. The model of Scharifker and Hills was used to analyze the current transients and it revealed that Cd-Pb electrocrystalization processes at low concentration is governed by three-dimensional progressive nucleation controlled by diffusion, while at higher concentration starts as a progressive nucleation then switch to instantaneous nucleation process. AFM images reveal that Cd-Pb film electrodeposited at low concentration is more roughness than Cd-Pb film electrodeposited at high concentrated solution.

• 한국표면공학회지
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• 제55권6호
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• pp.342-352
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• 2022

Purine catabolite screening enables reliable diagnosis of certain diseases. In this regard, the development of a facile detection strategy with high sensitivity and selectivity is demanded for point-of-care applications. In this work, the simultaneous detection of uric acid (UA), xanthine (XA), and hypoxanthine (HX) was carried out as model purine catabolites by surface-enhanced Raman Spectroscopy (SERS). The detection assay was conducted by employing high-aspect ratio Au nanopillar substrates coupled with in-situ Au electrodeposition on the substrates. The additional modification of the Au nanopillar substrates via electrodeposition was found to be an effective method to encapsulate molecules in solution into nanogaps of growing Au films that increase metal-molecule contact and improve substrate's sensitivity and selectivity. In complex solutions, the approach facilitated ternary identification of UA, XA, and HX down to concentration limits of 4.33 𝜇M, 0.71 𝜇M, and 0.22 𝜇M, respectively, which are comparable to their existing levels in normal human physiology. These results demonstrate that the proposed platform is reliable for practical point-of-care analysis of biofluids where solution matrix effects greatly reduce selectivity and sensitivity for rapid on-site disease diagnosis.

• 한국재료학회지
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• 제18권3호
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• pp.163-168
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• 2008

The morphology of three-dimensional (3D) cross-linked electrodeposits of copper and tin was investigated as a function of the content of metal sulfate and acetic acid in a deposition bath. The composition of copper sulfate had little effect on the overall copper network structure, whereas that of tin sulfate produced significant differences in the tin network structure. The effect of the metal sulfate content on the copper and tin network is discussed in terms of whether or not hydrogen evolution occurs on electrodeposits. In addition, the hydrophobic additive, i.e., acetic acid, which suppresses the coalescence of evolved hydrogen bubbles and thereby makes the pore size controllable, proved to be detrimental to the formation of a well-defined network structure. This led to a non-uniform or discontinuous copper network. This implies that acetic acid critically retards the electrodeposition of copper.

• 한국표면공학회지
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• 제32권6호
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• pp.686-694
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• 1999

Insoluble anodes of the Ta/Ir mixed metal oxide for electrodeposition of Ni-W alloy in ammoniacal citrate bath were prepared by thermal decomposition method. Ti plate was etched in boiling oxalic acid solution and coated with ethanol solution of $TaCl_{5}$ and $IrCl_4$ mixed in a fixed ratio, followed by drying and treating at various temperatures. The coating layer of these insoluble anode was characterized by SEM, EDX, XRD and DSC. The decomposition rate of citric acid in plating bath was determined by measuring the $CO_2$ gas evolved at the anodes with Gas Chromatography. Evolution of $CO_2$ gas from Ta/Ir oxide anodes decreased about 5% compared with that of Pt. The $CO_2$ gas evolution was increased with the amount of Ir-oxide in the coatings. The coatings which have more than 40% ratio of Ta content and heat-treated at the temperature higher than $400^{\circ}C$ showed better efficiency

• 한국인쇄학회지
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• 제18권2호
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• pp.133-141
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• 2000

Enhanced the value of badge good with the gold plating of emblem, sports pictogram, mascot in 2002 Asian Game and World Cup, applying the plating and coating technique to screen printing. In addition, tourist and characteristic goods were of great value and image of visual communication displayed outside. After the screen printing in the surface of stainless steel, it obtained the plate coloring of beautiful a black glossy with a black Ru plating. At the identical surface, it did that the electrodeposition coating process in order to making a conductor state of image areas and a nonconductor state of nonimage areas. After the electrodeposition process, it removed the printing ink of image areas with solvent. A manufacturing process, it removed the printing ink of image areas with solvent. A manufacturing process completed with copper, nickel and gold plating at bared metal surface.

• 한국기계가공학회지
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• 제18권2호
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• pp.38-43
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• 2019

Electrochemical etching is a popular process to apply metal patterning in various industries. In this study, the electrochemical etching using a patterned copper layer was proposed to fabricate multilayered structures. The process consists of electrodeposition, laser patterning, and electrochemical etching, and a repetition of this process enables the production of multilayered structures. In the fabrication of a multilayered structure, an etch factor that reflects the etched depth and pattern size should be considered. Hence, the etch factor in the electrochemical etching process using the copper layer was calculated. After the repetition process of electrochemical etching using copper layers, the surface characteristics of the workpiece were analyzed by EDS analysis and surface profilometer. As a result, multilayered structures with various shapes were successfully fabricated via electrochemical etching using copper layers.