• 한국세라믹학회지
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• 제37권3호
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• pp.227-232
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• 2000

The LSM-YSZ composite electrode as a mixture of LSM and YSZ shows percolation characteristics. It was identified that the polarization resistance of LSM-YSZ composite electrode depend on YSZ connectivity by changing powder size ratio of the DLSM/DYSZ. That is, YSZ in composite electrode showed low electrochemical activity without YSZ connectivity. However, the polarization resistance decreased abruptly with YSZ connectivity due to high electrochemical activity of YSZ in composite electrode. Because the amount of three phase boundary is dependent on LSM and YSZ particle size, the polarization resistance of cathode decreases as LSM and YSZ particle size decreases.

• Bulletin of the Korean Chemical Society
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• 제17권2호
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• pp.143-146
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• 1996

A continuous potential pulse is applied to a silver-working electrode on a pulsed amperometric detector (PAD) for detection of free cyanide and sulfide. The moving phase is 0.1 M sodium hydroxide, 0.5 M sodium acetate and 5% (v/v) ethylenediamine mixture, and the flow rate is 0.7 mL/min. Optimized pulse conditions include a -200 mV (vs. Ag/AgCl reference electrode) detection potential(Ed) for 60 msec and 50 mV cleaning potential (Ec) for 120 msec. The silver working electrode surface is not poisoned by cyanide or sulfide, and the PAD maintains long-term stability without loss of sensitivity and reproducibility at these pulse conditions. The detection limit of cyanide and sulfide separated by ion chromatography using an anion exchange column is 0.1 ppm and 0.05 ppm, respectively.

• 한국가스학회지
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• 제1권1호
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• pp.106-112
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• 1997

본 연구는 직류 저항회로의 개폐불꽃에 의한 폭발성 가스의 점화한계를 실험적으로 고찰하였다. 실험은 IEC형 불꽃점화 시험장치의 폭발용기에 폭발성 가스(메탄-공기 프로판-공기, 에틸렌-공기, 수소-공기)를 각각 넣고 텅스텐 전극과 카드뮴 전극사이에서 발생하는 3,200회의 개폐불꽃에 의한 점화유무를 확인하므로서 점화한계를 구하였다. 또한 실험장치의 점화감도교정을 실험한 후에 실시하므로서 실험의 정확성을 기하였다. 실험결과 최소 점화 전류값을 갖는 최소점화한계농도는 메탄-공기 8.3 [$Vol\%$], 프로판-공기 5.25[$Vol\%$], 에틸렌-공기 7.8[$Vol\%$], 수소-공기 21[$Vol\%$]로서 기존의 실험결과와 유사한 결과를 나타내었다. 또한 최소점화한계농도에서 전압과 최소점화잔류와의 관계를 구한 결과 최소점화한계는 메탄, 프로판, 에틸렌, 수소가스의 순서로 낮아졌고 점화전류의 크기는 전원전압의 크기와 반비례하고, 전극의 과열현상으로 인하여 전압 약 20(V)이하에서는 최소점화전류가 2(A)를 넘으면서 심화한계곡선이 급격히 상승한다는 것 등을 알 수 있었다.

• Carbon letters
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• 제15권3호
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• pp.210-213
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• 2014

Nitrogen-doped microporous carbons were prepared using a polyvinylidene fluoride/melamine mixture. The electrochemical performance of the nitrogen-doped microporous carbons after being subjected to different carbonization conditions was investigated. The nitrogen to carbon ratio and specific surface area decreased with an increase in the carbonization temperature. However, the maximum specific capacitance of 208 F/g was obtained at a carbonization temperature of $800^{\circ}C$ because it produced the highest microporosity.

• Bulletin of the Korean Chemical Society
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• 제17권11호
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• pp.995-999
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• 1996

A method for the determination of cobalt(Ⅱ) by differential pulse voltammetry using a carbon paste electrode constructed by incorporating 1-(2-pyridylazo)-2-naphthol(PAN) into a conventional carbon paste mixture composed of graphite powder and Nujol oil has been developed. Several influencing factors for the determination of cobalt(Ⅱ) were studied in detail and the optimum analytical conditions were found to be as follows: pH, 4.6; composition of electrode, 20%; temperature of deposition, 43 ℃; time of preconcentration, 15 min. Regeneration of the electrode surface for the continuous uses of the electrode was achieved by exposing the carbon paste electrode to an acidic solution. Response of the electrode was reproducible for the uses of five times and the relative standard deviations were 6.7 and 4.6% for 2.0×10-5 M and 4.0×10-6 M cobalt(Ⅱ), respectively. The calibration curve for cobalt(Ⅱ) obtained by differential pulse voltammetry was divided into two linear ranges of 1.7× 10-6-1.3×10-4 M and 2.0×10-7-8.0×10-7 M. The detection limit was estimated to be 1.3×10-7 M. The effects of coexisting ions were also investigated to test the applicability of the proposed method to the determination of cobalt(Ⅱ) in real samples.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.359-366
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• 2014

포화지방산과 인지질(DMPC)혼합 LB막에 대한 전기화학적 특성을 조사하였다. 포화지방산과 DMPC 혼합 단분자 LB막은 ITO glass에 Langmuir-Blodgett법을 사용하여 제막하였다. 전기화학적 특성은 $NaClO_4$ 용액에서 3 전극 시스템 (Ag/AgCl 기준전극, 백금선 카운터 전극 및 LB 필름이 코팅된 ITO 작업 전극)으로 순환전압전류법을 사용하여 측정하였다. 그 결과 포화지방산과 인지질(DMPC)의 LB막은 순환전압전류도표로부터 산화전류로 인한 비가역공정으로 나타났다. 포화지방산과 인지질(DMPC)혼합(몰비 1:1) LB막(C14, C16, C18, C20)에서 확산계수(D)는 0.05 N $NaClO_4$에서 각각 $1.2{\times}10^{-3}$, $2.1{\times}10^{-3}$, $1.4{\times}10^{-4}$ 및 $1.1{\times}10^{-3}cm^2/s$로 산출되었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.744-747
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• 2009

Plasma Display Panels (PDPs) have illustrated impressive results in terms of light emission efficiency of the Ne-Xe mixture compared with the He-Xe mixture. However, He-Xe has shown to achieve superior color purity. This paper presents the optimization of excitation efficiency and color purity for He-Ne-Xe ternary gas mixtures. Furthermore, we investigate the effect that a protective dielectric layer has on UV photon efficiency in a matrix known as electrode type PDP.

• 한국응용과학기술학회지
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• 제22권4호
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• pp.315-322
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• 2005

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with 4-octyl-4'-(5-carboxylpentamethyleneoxy)azobenzene (denoted as 8A5H) and $phospholipid(L-{\alpha}-dimyristoylphosphatidylcholine$, denoted as DMPC). LB films of 8A5H monolayer and 8A5H-DMPC were deposited by using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured 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 at various concentrations(0.1, 0.5, and 1.0mol/L) of $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rates were 50, 100, 150 and 200mV/s, respectively. As a result, LB films of 8A5H monolayer appeared irreversible process caused by only the oxidation current from the cyclic voltammogram and LB films of 8A5H-DMPC mixture were found to be caused by a reversible oxidation-reduction process.

• Journal of Biosystems Engineering
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• 제27권3호
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• pp.249-258
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• 2002

The fourteen different electrodes coated with polymeric lipid membrane were evaluated to selectively monitor the sweet, salty, sour and bitter tastes, and umami. The polymeric lipid membrane consisted of the three components, or polymer matrix, plasticizer and electroactive material, the compositional ratio of which was 1:1.25:1. Herein, the 14 different electroactive materials were used. Sucrose, NaCl, citric acid, caffeine and MSG were used as standard materials of sweet, salty, sour and bitter tastes, and umami. The linear responses of each electrode regarding 5 tastes were analyzed by means of the correlation coefficient between electric potential difference and concentration of a taste material when the linearity was based on a linear model and a thermodynamic model, respectively. As fur salty taste, the electrode coated with valinomycin had a selective linearity at the significance level of 0.01. For monitoring sweet taste, the electrode with oleylamine and the electrode with the mixture of tai-n-octylmethylammonium chloride and dioctylphosphate (2:8) showed the significant linearities at the levels of 0.05 and 0.10, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.753-756
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• 2001

This research made a study of MnO$_2$electrode for supercapacitor with a diffuser (Polyvinyl alcohol). Manganese dioxide was used as active material. We tried to increase specific surface area by adding PVA. Manganese dioxide was synthesized by a sol-gel method using fumaric acid and oxalic acid in low temperature with high yield. Therefore, We prepared Manganese dioxide powder. This powder was used by active materials. The electrode was made by a mixture of active material, ketjen-black which is a large specific surface area, and PVdF-co-HFP as binder agent with using Nickel mesh as current collector. Here we reported on the synthesis and electrochemical performance of a enhanced material. All active materials have been submitted to X-ray diffraction and Scanning electron microscopy.