• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.443-449
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• 2012

A investigation of electrochemical analysis of antibiotics Neomycin ($C_{23}H_{46}N_6O_{13}$) was searched using electrochemical square wave (SW) stripping and cyclic voltammetry (CV) using working sensor of the modified carbon nanotube combination electrodes, optimum diagnostic parameters were searched by anodic stripping, final conditions were attained to working range of 1.0-14.0 ng/L, detection limit (S/N) was found to be 0.6 ng/L. The developed method was discovered to be fitting in quality control in the food, pharmaceutical and other manufacturing sectors.

• Macromolecular Research
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• v.15 no.4
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• pp.379-384
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• 2007

Sulfonation of polyetheretherketones (PEEK) was carried out in order to fabricate commercial perfluorosulfonic acid membrane alternatives, which were characterized in terms of their ion exchange capacity, ionic conductivity, water swelling, methanol crossover and electrochemical performance in their direct application as a methanol fuel cell. A high ion exchange capacity, 1.88, was achieved with a sulfonation reaction time of 8 h, with a significantly low methanol crossover low compared to that of Nafion. However, the morphological stability was found to deteriorate for membranes with sulfonation reaction times exceeding 8 h. Electrochemical cell tests suggested that the fabrication parameters of the membrane electrode assembly based on the sulfonated PEEK membranes should be optimized with respect to the physicochemical properties of the newly prepared membranes.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.120-129
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• 1994

A numerical investigation has been carried out for the electrochemical reaction, mass and heat transfer characteristics of the Molten Carbonate Fuel Cell(MCFC) stack. The effects of cooling air channel and water gas shift reaction were taken into account. The current density distribution of electrodes, the molecular fractions of reactant gasses and three dimensional temperature distribution can be calculated and shown by several lines of equivalent values. The results have been compared with the existing ones, and reasonable agreement has been obtained. To examine the influence of changing parameters, such as the composition of reactant gases, the target average current density, the utilization of reactant gases, the cooling air inlet temperature and flow rates, the computer simulation has been done. The analysis method and computer program developed in this study will be greatly helpful to design and verify the optimum operating condition of MCFC stack.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.543-546
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• 2007

Herein, a new electrochemical method was described for the determination of ciprofloxacin based on the enhancement effect of an anionic surfactant: sodium dodecyl benzene sulfonate (SDBS). In pH 4.0 phosphate buffer and in the presence of 1.0 × 10-4 mol/L SDBS, ciprofloxacin yields a well-defined and sensitive oxidation peak at the carbon paste electrode (CPE). Compared with that in the absence of SDBS, the oxidation peak current of ciprofloxacin remarkably increases in the presence of SDBS. The experimental parameters, such as supporting electrolyte, concentration of SDBS, and accumulation time, were optimized for ciprofloxacin determination. The oxidation peak current is proportional to the concentration of ciprofloxacin over the range from 8.0 × 10-8 to 5.0 × 10-6 mol L-1. The detection limit is 2.0 × 10-8 mol L-1 after 2 min of accumulation. This new voltammetric method was successfully used to detect ciprofloxacin in drugs.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.722-727
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• 1995

The electrochemical impedance spectra of polyaniline film prepared by cyclic voltammetry have been investigated in 0.1 M aqueous sulfuric acid solution. Charge transfer resistances were rather low at the oxidized states in agreement with the conductive behavior reported at these potentials. The corresponding exchange current densities were very high. Large values of capacitance associated with the polymer have been found which vary as a function of the electrode potentials. An equivalent electrical circuit has been deduced from the impedance data. It was therefore possible to obtain the parameters of the ionic mass transport within the film.

• 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.

• Journal of Electrochemical Science and Technology
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• v.1 no.2
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• pp.69-74
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• 2010

Methodologies to improve photovoltaic performance of dye-sensitized solar cell (DSSC) are reviewed. DSSC is usually composed of a dye-adsorbed $TiO_2$ photoanode, a tri-iodide/iodide redox electrolyte and a Pt counter electrode. Among the photovoltaic parameters of short-circuit photocurrent density, open-circuit voltage and fill factor, short-circuit photocurrent density is the collective measure of light harvesting, charge separation and charge collection efficiencies. Internal quantum efficiency is known to reach almost 100%, which indicates that charge separation occurs without loss by recombination. Thus, light harvesting efficiency plays an important role in improvement of photocurrent. In this paper, technologies to improve light harvesting efficiency, including surface area improvement by nano-dispersion, size-dependent light scattering efficiency, bi-functional nano material, panchromatic absorption by selective positioning of three different dyes and transparent conductive oxide (TCO)-less DSSC, are introduced.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.115-122
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• 2004

A glassy carbon electrode(GCE) modified with nafion-DTPA (diethylene triamine-pentaacetic acid)-glycerol is used for the highly selective and sensitive determination of a trace amount of Cu(II). Various experimental parameters, which influenced the response of nafion-DTPA-glycerol modified electrode to Cu(II), are optimized. The Copper(II) is accumulated on the electrode surface by the formation of the complex in an open circuit, and the resulting surface is characterized by medium exchange, electrochemical reduction, and differential pulse voltammetry(DPV). The electrochemical response is evaluated with respect to concentration of modifier, pH and preconcentration time, quiet time, copper(II) concentration, and other variables. A linear range is obtained in the concentration range 1.0${\times}$10$^{-8}$ M-1.0${\times}$10$^{-6}$ MCu(II) with 7 min preconcentration time. The detection limit(3s) is as low as 2.36${\times}$10$^{-8}$ M (1.50 ppb).

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.107-112
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• 2014

Using a chlorosulphonated polyethylene rubber solution for a binder of graphite powder and ferrocene for a mediator, a rose leaf tissue-embedded biosensor was built. Linearity on the Hanes-Woolf plot showed the reduction of the substrate was attained through the catalytic power of the rose peroxidase in the experimental range of electrode potential. Furthermore, 10 or more electrochemical parameters demonstrated that the electrode exerts its sensing ability quantitatively. The foregoing gave the full conviction that rose tissue can be used in place of the currently marketed enzyme for the practical use of enzyme electrode.

• Bulletin of the Korean Chemical Society
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• v.17 no.8
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• pp.688-693
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• 1996

Tetradentate Schiff base ligands derived from 2-hydroxy-1-naphthaldehyde and aliphatic diamine have been synthesized. Cu(Ⅱ) complexes of Schiff base ligands have been synthesized from the free ligands and copper acetate. The mole ratio of ligand to copper was identified to be 1:1 by the result of elemental analysis and Cu(Ⅱ) complexes were in a four-coordinated configuration. The electrochemical redox process of Cu(Ⅱ) complexes in a DMF solution has been investigated by cyclic voltammetry, chronoamperometry, differential pulse voltammetry, and controlled potential coulometry. The redox process of Cu(Ⅱ) complexes is one electron transfer process in quasi-reversible and diffusion-controlled reaction. The electrochemical redox potentials and the kinetic parameters of Cu(Ⅱ) complexes are affected by the chelate ring of Schiff base ligands.