• 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.

• Journal of Electrochemical Science and Technology
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• v.7 no.2
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• pp.91-96
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• 2016

Oxidation behaviours of ash free coal (AFC), carbon, and H₂ fuels were investigated with a coin type molten carbonate fuel cell. Because AFC has no electrical conductivity, its oxidation occurs via gasification to H₂ and CO. An interesting behaviour of mass transfer resistance reduction at higher current density was observed. Since the anode reaction has the positive reaction order of H₂, CO₂ and H₂O, the lack of CO₂ and H₂O from AFC results in a significant mass transfer resistance. However, the anode products of CO₂ and H₂O at higher current densities raise their partial pressure and mitigate the resistance. The addition of CO₂ to AFC reduced the resistance sufficiently, thus the resistance reduction at higher current densities did not appear. Electrochemical impedance results also indicate that the addition of CO₂ reduces mass transfer resistance. Carbon and H₂ fuels without CO₂ and H₂O also show similar behaviour to AFC: mass transfer resistance is diminished by raising current density and adding CO₂.

• Journal of the Korean Chemical Society
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• v.15 no.6
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• pp.324-329
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• 1971

In order to evaluate the mechanism of electrolytic oxidation of iodate and to determine the optimum conditions for the electrolysis, studies were made using the cells without diaphragm and the lead peroxide anode. Results are summarized as followings: 1) Current density vs. anode potential curve by lead peroxide electrode had the different limiting current densities from platinum electrode and was more positive than platinum electrode. 2) Additions of potassium bichromate in the electrolyte contribute to maintain high current efficiency. 3) In the acid and alkaline regions, the current efficiencies decreased by reduction of iodate and discharge of hydroxyl ion, so maximum current efficiency was shown at pH 7. 4) Higher current density lowered the current efficiency in the region of 60-80% conversion of iodate. 5) Influence of the conversion on current efficiency in the region of 60-80% conversion of iodate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.920-923
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• 2004

We have investgated on the monolayer LB film of BASH-DMPC mixture on an ITO for the photoisomerization by light irradiation. We measured electrochemical properties by using cyclic voltammetry with a three-electrode system, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode in $NaClO_4$ solution at a variable concentration and monolayer LB films. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150 and 200 mV/s. As a results, LB films of 8A5H-DMPC appeared reversible process caused by the reduction-oxidation current from the cyclic voltammogram.

• Journal of Korean society of Dental Hygiene
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• v.7 no.4
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• pp.471-479
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• 2007

The purpose of this study was to examine the optimum condition of impulse during the anodic spark oxidation applying pulse current as well as to find the excellent condition for HA precipitation the after electrochemical hydrothermal treatment by cathode reduction method. After anodic spark oxidation, the anodized specimen and the Pt plate connected cathode and anode, respectively. Hydrothermal treatment performed at 90, 120, $150^{\circ}C$ for 2 hours in the electrolyte containing $K_2HPO_4$, $CaCl_2{\cdot}2H_2O$, Tris(Hydroxymethyl)-$(CH_2OH)_3\;CNH_2$(Aminomethane), and NaCl. The optimum impulse voltage for anodic spark oxidation was 350V. The optimum pulse cycle measured at 10 mS. The HA crystals precipitated excellently by cathode reduction at $150^{\circ}C$ for 2 hours. The phases of anatase, rutile, and HA coating on the surface of modified titanium surface immersed in Hanks' solution for 3weeks were detected by XRD measurement and the intensity of HA crystal phase has increased by temperature and time of hydrothermal treatment. According to the our experiments, we found that Pure Ti will be good materials of bioactivity and biocompatibility.

• Journal of Convergence for Information Technology
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• v.11 no.7
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• pp.104-110
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• 2021

A novel selective oxidation process has been developed for low source/drain (S/D) series resistance of the fin channel metal oxide semiconductor field effect transistor (MOSFET). Using this technique, the selective oxidation fin-channel MOSFET (SoxFET) has the gate-all-around structure and gradually enhanced S/D extension regions. The SoxFET demonstrated over 70% reduction in S/D series resistance compared to the control device. Moreover, it was found that the SoxFET behaved better in performance, not only a higher drive current but also higher transconductances with suppressing subthreshold swing and drain induced barrier lowering (DIBL) characteristics, than the control device. The saturation current, threshold voltage, peak linear transconductance, peak saturation transconductance, subthreshold swing, and DIBL for the fabricated SoxFET are 305 ㎂/㎛, 0.33 V, 13.5 𝜇S, 76.4 𝜇S, 78 mV/dec, and 62 mV/V, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.223-230
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• 2011

An electrolytic oxidation process was applied to remove odorous compounds from non-point odor sources including wastewater pipelines and manholes. In this study, a distance between the anode and the cathode of the electrolytic process was varied as a system operating parameters, and its effects on odor removal efficiencies and reaction characteristics were investigated. Odor precursors such as sediment organic matters and reduced sulfur/nitrogen compounds were effectively oxidized in the electrolytic process, and a change in oxidation-reduction potential (ORP) indicated that an stringent anaerobic condition shifted to a mild anoxic condition rapidly. At an electrode distance of 1 cm and an applied voltage of 30 V, a system current was maintained at 1 A, and the current density was 23.1 $mA/cm^{2}$. Under the condition, the removal efficiency of hydrogen sulfide in gas phase was found to be 100%, and 93% of ammonium ion was removed from the liquid phase during the 120 minute operating period. Moreover, the sulfate ion (${SO_4}^{2-}$) concentration increased about three times from its initial value due to the active oxidation. As the specific power consumption (i.e., the energy input normalized by the effective volume) increased, the oxidation progressed rapidly, however, the oxidation rate was varied depending on target compounds. Consequently, a threshold power consumption for each odorous compound needs to be experimentally determined for an effective application of the electrolytic oxidation.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.88-94
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• 2012

In this study, the current-voltage curves for metals were measured using cyclic voltammetry. The relationship between the electrochemical properties and surface states of metals were investigated by Scanning Electron Microscope (SEM). In cyclic voltammetry, we used a 3-electrode system for the electrochemical measurements. The measurement was conducted at the condition that consists of the first reduction from the initial potential to -1350 mV, continuous oxidation to 1650 mV, and last reduction to the initial potential. The scan rates were 50, 100, 150 and 250 mV/s. The results show the C-V characteristics of metals to be for an irreversible process, which was caused by the oxidation current from cyclic voltammogram, when monoethanolamine (MEA) was used as a corrosion inhibitor. When we used MEA as a corrosion inhibitor, the diffusion coefficient was decreased as the concentration of electrolyte was increased. In the SEM images of copper, we observed an increase of surface corrosion at the increased electrolyte concentration. Addition of $1.0{\times}10^{-3}M$ corrosion inhibitor MEA reduced the effect of corrosion prevention due to the relatively large diffusion coefficient at the electrolyte concentration of 0.1N.

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.399-405
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• 2020

Hollow copper oxide/multi-walled carbon nanotubes (CuO/MWCNT) composites were fabricated via an optimized infiltration-reduction-oxidation method, which is more facile and easy to control. The crystalline structure and morphology were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The as-prepared CuO/MWCNT composites deliver an initial capacity of 612.3 mAh·g^-1 and with 80% capacity retention (488.2 mAh·g^-1) after 100 cycles at a current rate of 0.2 A·g^-1. The enhanced electrochemical performance is ascribed to the better electrical conductivity of MWCNT, the hollow structure of CuO particles, and the flexible structure of the CuO/MWCNT composites.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.431-445
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• 1993

The purpose of this study was to observe corrosion characteristics of six dental amalgams and was to analyse corrosion products electrochemically. After each amalgam alloy and Hg was triturated as the direction of the manufacturer by using mechanical amalgamator, the triturated mass was inserted into the cylinderical metal mold ($12{\times}10mm$) and was condensed with 160kg/$cm^2$ by using the hydrolic press. The specimen was removed from the mold and was stored at room temperature for 1 week, and was polished with amalgam polishing kit. The anodic and cathodic polarization curve was obtained by using cyclic voltammetric method with 3-electrode potentiostat in saline for each amalgam and Ag, Sn, Cu plate specimen at $37{\pm}0.5^{\circ}C$. The potential sweep range was -1.7V~0. 4V(vs SCE) in working electrode and scan rate was 50mV/s and the exposed surface area of each specimen to the electrolytic solution was $0.79cm^2$. The results were as follows. 1. In anodic-cathodic polarization curve of amalgam specimens, two anodic current rising areas and two cathodic current peaks were obtained at the low Cu amalgam(CF, CS) specimen and three anodic current rising areas and three cathodic current peaks were obtained at the high Cu amalgam (TY, DS, HV) specimen. 2. As this compared with the anodic and cathodic current peak potentials of Sn, Cu and Ag specimen, the first cathodic current peak I c was caused by the reduction of divalent tin salt, second cathodic current peak IIIc results from the reduction of quadravalent tin salt, and third cathodic current peak me results from the reduction of copper salt. 3. As reverse potential sweeping was done repeatedly, anodic current was decreased slightly in all amalgam specimens.