• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.294-295
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• 2007

$LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ material was surface modified with Zr-phosphate. Scanning electron microscope, energy dispersive spectroscopy and electrochemical studies indicate that surface modification improve the rate capability. Electrochemical studies were performed by assembling 2032 coin cells with lithium metal as an anode.

• 한국응용과학기술학회지
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• 제18권1호
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• pp.12-19
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• 2001

Eu(III) exhibits one electron-transfer reduction at $E_{1/2}$ = -0.564 V(vs. Ag/AgCl) and the hypersensitive peak at 615 ㎚ corresponding to $^{5}D_{0}{\rightarrow}^{7}F_{2}$ transition in 0.1 M $LiClO_{4}$ aqueous solution. Upon the addition of 2,6-pyridine dicarboxylic acid(PDA) to the Eu(III) aqueous soultion, the reduction potential shifts negatively and the PDA, and the Eu(III)-PDA complex emits great fluorescence than free-Eu(III) ion at 615 nm. The results are interpreted in term of the electrochemical and spectrofluorometric studies.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.405-411
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• 2000

Electrochemical and spectroelectrochemical studies of cobalt-Schiff (Co-SB) base complexes, Co(salen) [N-N'-bis(salicylaldehyde)-ethylenediimino cobalt(II)] and Co(salophen) [N-N'-bis(salicylaldehyde)-1,2-pheny-lenediimino cobalt(II)], have been c arried out to test them as oxygen reduction catalysts. Both compounds were found to form an adduct with oxygen and exhibit catalytic activities for oxygen reduction. Comparison of spec-tra obtained from electrooxidized complexes with those from Co-SB complexes equilibrated with oxygen in-dicates that the latter are consistent with the postulated complex formed with oxygen occupying the coaxial ligand position, namely, Co(III)-SB·O2 - .The catalysis of oxygen reduction is thus achieved by reducing Co(III) in the oxygen-Co-SB adduct, releasing the oxygen reduction product, e.g., O2 - ., from the Co(II)-SB complex.

• Bulletin of the Korean Chemical Society
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• 제12권5호
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• pp.487-490
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• 1991

Electrochemical studies of alkali metal cations $(Na^+, K^+, Rb^+, Cs^+)$ were performed in methanolic solutions of 18-crown-6 and tetrabutylammonium salts at dropping mercury electrodes (DME) and thin mercury film electrodes (TMFE). All the cations investigated were reduced reversibly at DME in the absence and presence of 18-crown-6, and in the latter the limiting currents were decreased and the reduction potentials shifted to the negative direction. The reduction potentials of the metal ions (0.2 mM) in the presence of the crown (10 mM) were - 2.14 $(Na^+)$, - 2.26 $(K^+)$, - 2.20 $(Rb^+) and - 2.14 $(Cs^+)$ V vs. SCE, respectively. The measured potentials were rationalized with ion recognition of the cations by the crown. Electroreduction at TMFE were highly irreversible. A new representation method of ion recognition is presented. In aqueous solutions, electroreduction of the alkali metal ions were characterized by adsorption.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.43-44
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• 2022

In this study, the optimum amount of chloride ions is used to collaborate with hybrid corrosion inhibitor for carbon steel rebar treatment in simulated pore concrete (SCP) solution is discovered. The corrosion inhibition performance of hybrid inhibitors is carried on by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP). The highest corrosion inhibition resistance is found in case of LP-C2 after 240 h exposure. Surface studies including scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to figure out the surface morphology of the steel rebar treated with hybrid inhibitors in order to collaborate well with electrochemical studies. Anodic type inhibition action was confirmed by potentiodynamic polarization study.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.65-66
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• 2021

In this study, the optimum amount of hybrid inhibitors i.e. L-Arginine (LA) and sodium phosphate tribasic dodecahydrate (SP), applied for carbon steel rebar in simulated pore concrete (SCP) solution contaminated with 3.5 wt.% NaCl, was discovered. The corrosion inhibition performance of hybrid inhibitors was investigated by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization. The highest corrosion inhibition efficiency was found as 99.52% corresponding to 2% LA and 0.25% SP after 210 h exposure. Anodic type inhibition action was confirmed by potentiodynamic polarization study. Surface studies including scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to figure out the surface morphology of the steel rebar treated with hybrid inhibitors in order to collaborate with electrochemical studies.

• 전기화학회지
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• 제7권2호
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• pp.108-123
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• 2004

최근 근접장 광학주사현미경 (NSOM)을 이용한 재료의 표면 및 구조 분석은 생물학에서 재료과학에까지 광범위하게 응용되고 있다. 본 총설에서는 기존의 NSOM을 여러가지 현미경법 (광학, 형광, 전자 및 전기화학 현미경 관찰법)과 접목하여 구성한 다기능 NSOM (multi-functional NSOM, mf-NSOM)을 이용, 나노 재료의 고분해능 이미징에 대한 원리와 응용을 고찰하였다. 본 mf-NSOM 기술을 이용하여 실제로 Al합금 및 다결정 Ti 표면에서의 공식 (pitting)을 일으키는 취약 지역을 광학적으로 분석한 결과를 기술하였다. 또한, mf-NSOM과 레이저 기술을 통해 나노 Ag 입자를 형성하고 실시간 분석한 연구결과에 대해서도 소개하고자 한다.

• 대한화학회지
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• 제58권5호
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• pp.437-444
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• 2014

변전위법과 전기화학적 임피던스측정법(electrochemical impedence spectroscopy)을 이용하여 borate 완충용액에서 Co-RDE의 전기화학적 부식과 부동화에 대하여 조사하였다. Tafel 기울기, 코발트 회전원판전극의 회전속도, 임피던스 그리고 부식전위와 부식전류의 pH 의존성으로부터 코발트의 부식과 부동화 반응 메커니즘과 환원반응에서의 수소 발생 반응구조를 제안하였다. EIS data로부터 등가회로를 제안하였으며 산화반응의 영역별로 전기화학적 변수들을 측정하였다. 부식전위에서 측정된 Nyquist plot의 induction loop가 낮은 주파수 영역에서 관측되는 것으로 보아 흡착/탈착 현상이 Co의 부식과정에 영향을 미치는 것으로 보인다.

• Journal of Electrochemical Science and Technology
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• 제3권3호
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• pp.135-142
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• 2012

Over the past few years, $LiFePO_4$ has been actively studied as a cathode material for lithium-ion batteries because of its advantageous properties such as high theoretical capacity, good cycle life, and high thermal stability. However, it does not have a very good power capability owing to the low lithium-ion diffusivity and poor electronic conductivity. Reduction in particle size of $LiFePO_4$ to the scale of nanometers has been found to dramatically enhance the above properties, according to many earlier reports. However, because of the intrinsically low tap density of nanomaterials, it is difficult to commercialize this method. Many studies are being carried out to improve the volumetric energy density of this material and many methods have been reported so far. This paper provides a brief summary of the synthesis methods and electrochemical performances of micro-spherical $LiFePO_4$ having high volumetric energy density.

• Journal of Electrochemical Science and Technology
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• 제2권2호
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• pp.103-109
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• 2011

Nanocrystalline $LiFePO_4$ powders were prepared at 660-$670^{\circ}C$ in an Ar atmosphere using two different synthetic routes, solid-state and sol-gel. Both materials showed well-developed XRD patterns without any impurity peaks. Particles composed in the range of 200-300 nm from the solid-state method, and 50-100 nm from the sol-gel method, were confirmed through scanning electron microscopy and dynamic light scattering. The $LiFePO_4$ obtained by the sol-gel method offered a high discharge capacity (153 mAh/g) and stable discharge behavior, even at elevated temperatures (50 and $60^{\circ}C$), whereas poor electrochemical performance was observed from the solid-state method. Rate capability studies for sol gel-derived $LiFePO_4$ ranged from 0.2 to 30 C, which revealed excellent retention over 70 cycles with a 99.9% capacity.