• Title/Summary/Keyword: Electrochemical Behaviors

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Electrochemical Investigation of Bovine Hemoglobin at an Acetylene Black Paste Electrode in the Presence of Sodium Dodecyl Sulfate

  • Zhan, Guoqing;Li, Chunya;Luo, Dengbai
    • Bulletin of the Korean Chemical Society
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    • v.28 no.10
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    • pp.1720-1724
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    • 2007
  • Electrochemical behaviors of bovine hemoglobin (Hb) at an acetylene black paste electrode based on the enhancement effect of sodium dodecyl sulfate (SDS) were investigated. In the optimal conditions, a very weak reduction peak was observed at an acetylene black paste electrode for hemoglobin in the absence of SDS. However, the reduction peak current increased remarkably after the addition of 4.0 × 10?4 mol L?1 SDS, suggesting that SDS exhibits obvious enhancement effect to the determination of hemoglobin. All the experimental parameters, such as pH value, concentration of SDS, accumulation time and accumulation potential were optimized for hemoglobin analysis. The proposed method possesses high sensitivity (detection limit is 3.0 × 10?9 mol L?1), wide linearity (6.0 × 10?9 to 6.0 × 10?7 mol L?1), rapid response and low cost. Finally, the method was successfully employed to determine hemoglobin in a spiked sample.

Comparative Study of Non-Electrochemical Hysteresis Models for LiFePO4/Graphite Batteries

  • Ma, Jiachen;Xie, Jiale;Bai, Kun
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1585-1594
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    • 2018
  • The estimation of $LiFePO_4$/graphite battery states suffers from the prominent hysteresis phenomenon between the respective open-circuit voltage curves towards charging and discharging. A lot of hysteresis models have been documented to investigate the hysteresis mechanism. This paper reviews and deeply interprets four non-electrochemical hysteresis models and some improvements. These models can be conveniently incorporated into commonly used equivalent circuit models to reproduce battery behaviors. Through simulation and experimental comparisons of voltage predictions and state-of-charge estimations, the pros and cons of these models are presented.

Characteristics of HOMO and LUMO Potentials by Altering Substituents: Computational and Electrochemical Determination

  • Kim, Young-Sung;Kim, Sung-Hoon;Kim, Tae-Kyung;Son, Young-A
    • Textile Coloration and Finishing
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    • v.20 no.5
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    • pp.41-46
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    • 2008
  • Recently, computational calculation of molecular energy potentials and electrochemical reduction/oxidation behaviors are of very importance in view point of prediction of dye's properties such as energy levels and bandgaps of absorption. This can be influenced by their different constituents or substituents in chromogen molecules. Structural conformations and properties with computational modeling calculation are numerically simulated, which are fully or partly based on fundamental laws of physics. In addition, cyclic voltammetric measurement was used to obtain the experimental redox potential values, which were compared to the computed simulation values.

Electrodeposition of Conducting Polymers on Copper in Nonaqueous Media by Corrosion Inhibition

  • Lee, Seonha;Lee, Hochun
    • Journal of Electrochemical Science and Technology
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    • v.3 no.2
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    • pp.85-89
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    • 2012
  • This study demonstrates the direct anodic electrodeposition of polypyrrole (PPy), poly(3,4-ethyl-enedioxythiophene) (PEDOT), and polythiophene (PTh) on Cu electrodes by employing a corrosion inhibitor, succinonitrile (SN). SN was found to suppress anodic Cu dissolution beyond the oxidation potential of the polymer monomers. It is also revealed that the Cu surface passivated by SN is still adequately conductive to allow the redox reaction of 1,4-difluoro-2,5-dimethoxybenzene (FMB) and the oxidation of the polymer monomers. Through both cyclic voltammetry and galvanostatic techniques, PPy, PEDOT, and PTh films were successfully synthesized on Cu electrodes in the presence of SN, and the redox behaviors of the films were evaluated.

Nucleation Process of Indium on a Copper Electrode

  • Chung, Yonghwa;Lee, Chi-Woo
    • Journal of Electrochemical Science and Technology
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    • v.4 no.3
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    • pp.93-101
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    • 2013
  • The electrodeposition of indium onto a copper electrode from an aqueous sulfate solution containing $In^{3+}$ was studied by means of cyclic voltammetry and chronoamperometry. Reduction and oxidation of indium on copper were investigated by using cyclic voltammograms at different negative limiting potentials and at different scan rates in cumulative cycles. Cyclic voltammograms indicated that reduction and oxidation processes of indium could involve various reactions. Chronoamperometry was carried out to analyze the nucleation mechanism of indium in the early stage of indium electrodeposition. The non-dimensional plot of the current transients at different potentials showed that the shape of the plot depended on the applied potential. The nucleation of indium at potential step of -0.6~-0.8 V was close to progressive nucleation limited by diffusion. However the non-dimensional plot of current transients for the indium nucleation showed different behaviors from theoretical curves at the potential step lower than -0.8 V.

Electrochemical Study of UBM Ni Prepared by Electroless Plating (무전해 도금법을 이용한 UBM 니켈 형성의 전기화학적 고찰)

  • Lee Jae Ho;Lee In Geon;Gang Tak;Kim Nam Seok;O Se Yong
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2003.11a
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    • pp.118-121
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    • 2003
  • The electrochemical behaviors of UBM nickel were investigated. Electrode potential has been changed with the surface composition. Zinc is dissolved into the solution immediately after immersion. Electrode potential has three distinct regions: Zinc dissolution region, transient region and nickel plating region. The effects additives on electrode potential and polarization curves were also investigated. The addition of suppressor lowered the current density which is related with deposition rate.

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Characteristics of high energy density hybrid capacitor using metal oxide electrode (금속산화물 전극을 사용한 고 에너지밀도 하이브리드 커패시터 특성)

  • Yoon, Hong-Jin;Shin, Yoon-Sung;Lee, Jong-Dae
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.3
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    • pp.329-334
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    • 2011
  • The electrochemical performances of an asymmetric hybrid capacitor were investigated using $LiFePO_4$ as the positive electrode and active carbon fibers(ACF) as the negative electrode. The electrochemical behaviors of a nonaqueous hybrid capacitor were characterized by constant current charge/discharge test. The specific capacitance using $LiFePO_4$/ACF electrode turned out to be $0.87F/cm^2$ and the unit cell showed excellent cycling performance. This hybrid capacitor was able to deliver a specific energy as high as 178 Wh/kg at a specific power of 1,068 W/kg.

A Study on Electroless Ni-B Plating with DMAB as Reducing Agent. I. The Electrochemical Behavior of Precipitation Reaction on Austenite Stainless Steel Substrates (DMAB를 사용한 무전해 Ni-B 합금 도금 I. 오스테나이트 스텐레스강 상의 석출반응에 대한 전기화학적 거동)

  • 이창래;박해덕;강성군
    • Journal of the Korean institute of surface engineering
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    • v.32 no.2
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    • pp.172-181
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    • 1999
  • The effect of the DMAB concentration, temperature, deposition time, and stabilizer concentration on the precipitation reaction of the electroless nickel plating using dimethylamine borane (DMAB) as reducing agent was investigated to by the weight gain and electrochemical method. The deposition rate was dependent with DMAB concentration. The polarization resistance of the precipitation reaction was reduced with DMAB concentration. The precipitation reaction rate of Ni-B deposits was controlled by the oxidation rate of DMAB as the source of electron. The boron content of the deposit was constant at about 5.5wt%, even when DMAB concentration in the solution was increased. The effect of temperature and stabilizer ($Pb(NO_3)_2$) concentration on deposition rate was shown to have co-dependent behaviors.

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Electrochemical Investigation of Animal Tissue Embedded Biosensor Bound with Ethylene-Propylene Rubber

  • Yoon, Kil-Joong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2913-2917
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    • 2010
  • When rubber dissolved in toluene was used as a binding material of graphite powder, the mechanical robustness of the carbon paste was guaranteed by the fast volatility of the solvent immediately after electrode construction. This characteristic of the rubber solution met qualifications for practical use of carbon paste electrodes and enabled the design of a new enzyme electrode bound with EPDM. In order to confirm whether the electrode shows quantitative electrochemical behaviors or not, its kinetic parameters, e. g. the symmetry factor (0.2), the exchange current density ($3.66\;{\mu}A/cm^2$), the capacity of the double layer ($2.0{\times}10^{-5}\;F$), the Michaelis constant ($4.39{\times}10^{-3}\;M$), the diffusion coefficient of substrate ($2.58{\times}10^{-12}\;cm^2/sec$), the time constant (0.018 sec) and other factors were investigated.

Ion and solvent transport during the redox reaction of Polypyrrole and poly(N-substituted pyrrole) films in aprotic solutions

  • Lee Hochun;Kwak Juhyoun
    • Journal of the Korean Electrochemical Society
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    • v.1 no.1
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    • pp.52-54
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    • 1998
  • Polypyrrole (PPy), Poly(N-methyl Pyrrole) (PMPy) and Poly(N-phenyl Pyrrole) (PPhPy) films in acetonitrile (Af and propylene carbonate (PC) have been compared focusing on their different ion and solvent transport behaviors. During the redox reaction of PPy films, cation, anion, and solvent take part in mass transport. Whereas during the redox reaction of PMPy and PPhPy films, anion and solvent transport are dominant but cation transport is negligible. In addition, solvent transport occurs in the same direction with cation transport for PPy films. On the other hand, solvent transport occurs in the opposite direction to anion transport for PMPy films, and it changes its amount and direction with the kind of the dopant anion and the solvent used at electropolymerization for PPhPy films.