• 전기화학회지
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• 제8권1호
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• pp.6-11
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• 2005

직접보로하이드라이드 연료전지는(direct borohydrides fuel cell. DBFC) 직접메탄을 연료전지가 갖는 메탄을 크로스오버(crossover)문제를 해결할 수 있어서, 휴대용 및 이동용 전원으로 활용하기 위하여 새롭게 대두되고있는 연료전지이다. 본 논문에서는 직접보로하이드라이드 연료전지의 전극제조 공정 확립을 위하여 여러 가지의 연료극 및 공기극 촉매를 선정하고 열가압법 (hot pressing)으로 전극을 제조하여 이에 대한 성능 특성을 고찰하였다. 공기극 촉매로는 Pt/C와 Pt black을 사용하였고, 연료극 촉매로는 Pt/C. Pt black, Au/C, $AB_5$ alloy를 사용하였다 제조된 전극 촉매는 XRD, SEM, EDS 등을 통한 특성 분석과 단위전지 운전을 통하여 I-V특성 분석이 이루어졌다. 다양한 촉매 조합을 통하여 촉매별 단전지 테스트를 한 결과 공기극 및 연료극 촉매를 Pt/C로 했을 때 가장 높은 성능인 366mW/mg을 얻을 수 있었다.

• 한국재료학회지
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• 제18권1호
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• pp.12-17
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• 2008

Carbon nanotube (CNT) cathodes were fabricated using nano-sized silver (Ag) powders as a bonding material between the CNTs and cathode electrodes. The effects of the powder size on the sintering behavior, the current density and emission image for CNT cathodes were investigated. As the diameter of the Ag powders decreases to 10 nm, the sintering temperature of the CNT cathode was lowered primarily due to the higher specific surface area of the Ag powders. In this study, it was demonstrated that nano-sized Ag powders can be feasibly used as a bonding material for a screen-printed CNT cathode, yielding a high current density and a uniform emission image.

• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.54-61
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• 2018

In this study, two aspects were analyzed about the robot for removal of explosive devices. First, the cost analyses were performed to provide a reasonable solution for the acquirement of the system. It is processed by an engineering estimate method and the process was consisted of two ways : a system development expense and a mass production unit price. In additions, the resultant cost analyses were compared between the cases excluding and including a mines detection system. As results, in the case of the acquirement of the robot system for removal of explosive devices, it is recommended that the performance by improving the mines detection ability should be considered preferentially rather than the cost because the material cost for the mines detection system is negligible compared to the whole system cost. Second, as a way for improving the system performance by the mine detection function, the carbon nanotube (CNT) based sensor technology was studied in terms of sensitivity and simple productivity with presenting its preliminary experimental results. The detection electrodes were formed by a photolithography method using a photosensitive CNT paste. As results, this method was shown as a scalable and expandable technology for the excellent mines detection sensors.

• 대한화학회지
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• 제37권8호
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• pp.723-729
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• 1993

탄소분말과 Nujol oil의 carbon paste 혼합물에 1-(2-pyridylazo)-2-naphthol (PAN)을 섞어서 Cu(Ⅱ)이온에 감응하는 수식전극을 제작하였다. Cu(II) 이온이 포함된 완충용액에 전극을 담구어 전위를 가하지 않고 PAN-수식전극의 표면에 Cu(II) 이온을 석출시킨 후, 전해액으로 옮겨 일정시간 동안 일정 전위에서 환원시켰다. 그런 다음 양의 방향으로 전위를 주사함으로써 좋은 전압전류파를 얻을 수 있었다. 전극표면을 산용액에 담금으로써 재생시킬 수 있었다. 전극의 재현성은 석출/측정/재생의 순으로 5회 반복실험하여 조사한 결과 상대표준편차는 6.1${\%}$였다. 시차펄스 전압전류법으로 조사한 경우 2.0 ${times}$ 10$^{-7}$M에서 1.0 ${times}$ 10$^{-6}$ M의 농도 범위에 걸쳐 직선성이 성립했으며, 검출한계는 6.0 ${times}$ 10$^{-8}$ M이었다. Cu(II) 이온을 정량하는데 있어서 EDTA와 oxalate 이온을 제외한 다른 공존이온의 영향을 별로 받지 않았다.

• Journal of Biosystems Engineering
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• 제41권2호
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• pp.75-84
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• 2016

Purpose: In-situ water quality monitoring based on ion-selective electrodes (ISEs) is a promising technique because ISEs can be used directly in the medium to be tested, have a compact size, and are inexpensive. However, signal drift can be a major concern with on-line management systems because continuous immersion of the ISEs in water causes electrode degradation, affecting the stability, repeatability, and selectivity over time. In this study, a computer-based nitrate monitoring system including automatic electrode rinsing and calibration was developed to measure the nitrate concentration in water samples in real-time. Methods: The capabilities of two different types of poly(vinyl chloride) membrane-based ISEs, an electrode with a liquid filling and a carbon paste-based solid state electrode, were used in the monitoring system and evaluated on their sensitivities, selectivities, and durabilities. A feasibility test for the continuous detection of nitrate ions in water using the developed system was conducted using water samples obtained from various water sources. Results: Both prepared ISEs were capable of detecting low concentrations of nitrate in solution, i.e., 0.7 mg/L $NO_3-N$. Furthermore, the electrodes have the same order of selectivity for nitrate: $NO_3{^-}{\gg}HCO_3{^-}$ > $Cl^-$ > $H_2PO_4{^-}$ > $SO{_4}^{2-}$, and maintain their sensitivity by > 40 mV/decade over a period of 90 days. Conclusions: The use of an automated ISE-based nitrate measurement system that includes automatic electrode rinsing and two-point normalization proved to be feasible in measuring $NO_3-N$ in water samples obtained from different water sources. A one-to-one relationship between the levels of $NO_3-N$ measured with the ISEs and standard analytical instruments was obtained.

• 전기화학회지
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• 제8권1호
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• pp.1-5
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• 2005

높은 비표면적을 갖는 carbon과 유기용매 전해질 사이의 계면에서 생기는 전기이중층용량을 기본으로 작동하는 전기이중층 캐패시터는 IC memories, microcomputer 등으로 폭 넓게 사용되며 maintenance-free의 영구적인 back-up용 전원으로 넓게 사용되고 있다 EDLC에 사용되는 전해질은 이온 전도도가 높아야 하고 사용되는 온도 범위가 넓어야 한다. 그리고 고전압을 인가했을 때 전해질이 전기화학적으로 안정해야 한다. 본 실험에서는 고전압에서 안정적인 액상 유기계 전해질을 사용하여 전기이중층캐패시터의 전기화학적 특성을 확인하였다. Paste rolling법으로 제조된 탄소전극과 $1M-LiPF_6$ in PC-GBL-DEC (volume ratio 1:1:2)의 유기용매전해질을 사용한 전기이중층캐패시터가 64F/g의 우수한 비축전용량을 발현하였다

• Bulletin of the Korean Chemical Society
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• 제11권3호
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• pp.200-205
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• 1990

Chemically modified electrodes(CMEs), based on 2-imino-1-cyclopentane-dithiocarboxylic acid (icdc) containing carbon paste, have been characterized using cyclic voltammetric techniques. Ag(I) was chemically deposited on the CMEs, and voltammograms were obtained with the electrode in a separate buffer solution. The CME surface can be regenerated with exposure to acid and reused for deposition. In 10 deposition/measurement/regenerate cycles, the linear response have been reproduced up to $1{\times}10^{-6}$ M in linear sweep voltammetry and 1${\times}$10-8 M in differential pulse voltammetry with relative standard deviation of 5.2% and 12.4%, respectiveiy. The sensitivity increased with deposition time and scanning rate, and detection limit was $1{\times}10^{-7}M\;and\;1{\times}10^{-9}M$ at 20 minutes deposition in the linear sweep voltammetry and differential pulse voltammetry, respectively. The presence of some metal ions does not influence the silver ion response. Satisfactory results were obtained for the analysis of the silver ion for a variety of reference materials without interference of Hg ion at the condition of pH = 5-6.

• 분석과학
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• 제23권2호
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• pp.165-171
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• 2010

글루코스 옥시다아(GOx)제 고정화 바이오센서를 두 가지 방법으로 제조 하였다. 첫 번째 방법은 폴리(maleic anhydride) 그래프트 탄소나노튜브(PMAn-g-MWCNT) 전극에 감마선 조사법으로 제조 된 Au 나노입자를 물리적으로 흡착시킨 후, GOx을 고정화 시켜 바이오센서를 제조한 경우이고, 다른 하나는 PMAn-g-MWCNT 전극에서 Au 이온을 전기화학적으로 환원시켜 Au 나노입자를 코팅 시키고, 그 위에 GOx을 고정화 시켜 바이오센서를 제조 한 경우이두. 제조된 바이오센서에 대해 효율 평가를 수행 하였는데, 물리적 흡착법으로 제조된 전극의 경우 검출 범위는 $30\;{\mu}M\sim100\;{\mu}M$이었으며, 검출한계는 $15\;{\mu}M$이었다. 또한 ascorbic acid와 uric acid에 대한 검출한계는 7.6%이었다. 물리적으로 Au 나노입자가 흡착된 전극의 경우가 글루코스 측정에 매우 우수한 전극임을 확인 하였다.

• Journal of Electrochemical Science and Technology
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• 제8권1호
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• pp.43-52
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• 2017

In this paper, for the first time, the electroanalytical study of Triethylenediamine, TEDA was done on a typically graphene modified carbon paste electrode (Gr/CPE) in pH=10.5 of phosphate buffer solutions (PBS). The surface morphology of the bare and modified electrodes was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electro-oxidation of TEDA was investigated at the surface of modified electrode. The results revealed that the oxidation peak current of TEDA at the surface of Gr/CPE is 2.70 times than that shown at bare-CPE. A linear calibration plot was observed in the range of 1.0 to 202.0 ppm. In this way, the detection limit was found to be 0.18 ppm. The method was then successfully applied to determination of TEDA in aqueous samples obtained from two kinds of activated carbon from the masks of war. On the other hand, density functional theory (DFT) method at B3LYP/6-311++G** level of theory and a conductor-like Polarizable Continuum Model (CPCM) was used to calculate the $pK_a$ values of TEDA. The energies of lowest unoccupied molecular orbital ($E_{LUMO}$) and highest occupied molecular orbital ($E_{HOMO}$), gap energy (${\Delta}E$) and some thermodynamic parameters such as Gibbs free energy of TEDA and its conjugate acid ($HT^+$) were calculated. The results of calculated $pK_a$ were found to be in good agreement with the experimental values.

• 분석과학
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• 제10권3호
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• pp.187-195
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• 1997

[16]-ane-$S_4$/탄소분말 함량비를 50%로 하여 nujol oil과 혼합하여 수식전극을 제조하였다. $5.0{\times}10^{-4}M$ $Ag^+$를 포함하는 pH 4.5인 아세트 완충용액에 수식전극을 담가 $Ag^+$를 전극 표면에 흡착시켰다. 이 때 흡착시간을 15분으로 하고 전해환원시키는 시간은 -0.3V vs S.C.E에서 2분으로 하였다. 또한 0.1M $HNO_3$ 용액으로 전극을 활성화시켰으며 한번 활성화한 전극은 10회까지 사용이 가능하였다. 최적 분석조건에서 미분펄스 전압전류법으로 $5.0{\times}10^{-7}{\sim}1.5{\times}10^{-6}M$ 사이의 농도 범위에서 정량해 보았을 때 직선성이 잘 성립하였으며, 검출한계는 $2.0{\times}10^{-7}M$이었다. 대부분의 금속들은 방해를 주지 않았으나, Cu(II)은 방해를 나타내었다.