• 공업화학
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• 제21권4호
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• pp.405-410
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• 2010

P25와 Dyesol $TiO_2$ (Titanium dioxide)를 사용하여 두께와 소성 온도가 다른 전극을 제조하여 염료감응형 태양전지(Dye Sensitized Solar Cell, DSSC)를 제조한 후 광 변환 효율을 측정하였다. 소성 전 후의 $TiO_2$ 작업 전극의 두께 변화는 FE-SEM을 사용하여 시편의 cross section을 확인하여 비교하였다. 또한 상대전극인 Pt의 소성 온도에 따른 DSSC의 효율 변화도 측정하였다. P25를 활용한 DSSC는 doctor blade로 1층으로 도포 후, $500^{\circ}C$에서 30 min 동안 소성한 작업 전극(${\sim}20.4{\mu}m$)과 $350^{\circ}C$에서 30 min 동안 소성한 Pt 상대 전극으로 제조한 셀이 3.8%의 광효율을 나타내었다. Dyesol $TiO_2$를 활용하여 1층으로 도포 후, $500^{\circ}C$에서 30 min 동안 소성한 작업전극(${\sim}9.1\;{\mu}m$)과 $450^{\circ}C$에서 30 min 동안 소성한 Pt 상대 전극으로 제조한 셀이 5.8%의 광 효율을 나타냄을 알았다.

• 대한화학회지
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• 제44권1호
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• pp.17-23
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• 2000

전기화학적으로 중합한 $[Ru(v-bpy)_3]^{2+}$의 다가 양이은성 고분자 피막전극을 $PF6^-/ClO_4^-$대이온의 비가 1:1 정도 되게 한 후에 우라늄과의 착물의 안정도상수가 각각 38.6과 17.5인 xylenoI orange와 diethyldithiocarbamate로 변성한 전극을 제작하였다. 이를 이용하여 용액중의 U(VI)을 정량할 수 있는 여러 회 사용이 가능한 전극을 제작하였다. 이 때에 분석용 신호를 얻기 위한 전극은 Pt/p-$[Ru(v-bpy)_3]^{2+}$, ligand, U(VI)이며 염화은 기준전극을 사용하였다. 벗김전압전류 과정에서는 전자전달이 지배적인 과정이었으며, 검정선은 $1.0{\times}10^{-3}{\sim}1.0{\times}10^{-7}$ M 범위에서 0.99의 좋은 상관관계와 5${\sim}$8%의 상대 표준편차를 나타냈다.

• 한국재료학회지
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• 제21권2호
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• pp.89-94
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• 2011

In this work, fabrication and electrochemical analysis of an individual multi-walled carbon nanotube (MWNT) electrode are carried out to confirm the applicability of electrochemical sensing. The reactive ion etching (RIE) process is performed to obtain sensitive MWNT electrodes. In order to characterize the electrochemical properties, an individual MWNT is cut by RIE under oxygen atmosphere into two segments with a small gap: one segment is applied to the working electrode and the other is used as a counter electrode. Electrical contacts are provided by nanolithography to the two MWNT electrodes. Dopamine is specially selected as an analytical molecule for electrochemical detection using the MWNT electrode. Using a quasi-Ag/AgCl reference electrode, which was fabricated by us, the nanoelectrodes are subjected to cyclic voltammetry inside a $2{\mu}L$ droplet of dopamine solution. In the experiment, RIE power is found to be a more effective parameter to cut an individual MWNT and to generate "broken" open state, which shows good electrochemical performance, at the end of the MWNT segments. It is found that the pico-molar level concentration of analytical molecules can be determined by an MWNT electrode. We believe that the MWNT electrode fabricated and treated by RIE has the potential for use in high-sensitivity electrochemical measurement and that the proposed scheme can contribute to device miniaturization.

• 공업화학
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• 제25권6호
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• pp.592-597
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• 2014

본 연구에서는 리튬이차전지의 음극활물질로 graphite의 전기화학적 특성을 향상시키기 위하여 졸-겔 법에 의한 graphite/$SiO_2$ 복합소재를 제조하였다. 제조된 graphite/$SiO_2$ 합성물은 XRD, FE-SEM과 EDX를 사용하여 분석하였다. $SiO_2$에 의해 표면 개질된 graphite는 SEI 층을 안정화시키는데 장점을 보여 주었다. Graphite/$SiO_2$ 전극을 작업 전극으로, 리튬메탈을 상대전극으로 하여 리튬이차전지의 전기화학 특성을 조사하였다. $LiPF_6$ 염과 EC/DMC 용매를 전해질로 사용하여 제조한 코인 셀의 전기화학적 거동은 충방전, 사이클, 순환전압전류, 임피던스 테스트를 진행하여 평가하였다. Graphite/$SiO_2$ 전극을 사용한 리튬이차전지는 graphite 전극을 사용한 전지보다 우수한 특성을 보여주었으며, 0.1 C rate에서 465 mAh/g의 용량을 보여주었다. 또한 개질된 graphite 전극은 0.8 C rate에서 99%의 용량 보존율을 보여주었다.

• 에너지공학
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• 제11권3호
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• pp.254-261
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• 2002

The fabrication method for the main components of the polymer electrolyte membrane fuel cell stack such as electrodes, membrane-electrode assemblies, and bipolar plates was established for the effective electrode area of 240 ㎠. A counter-flow type 100-cell stack was fabricated by using the above components and then a maximum power of 7.44 kW for H$_2$/O$_2$ and 5.56 kW for H$_2$/air could be obtained at 70$\^{C}$ and 1 atm. It was seen that the distribution of the OCV for unit cells in the stack was uniform but the voltage deviation increased as the load increased due to the IR drop and the electrode polarization. The stack was applied to the power source of the fuel cell/battery hybrid electric golf car. It produced about 1 kW at a room temperature operation during the test run, which occupied about 43% of the total power required by the 2.3 kW motor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1232-1235
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• 2004

The purpose of this study is to design electrical stimulation system for pharyngeal dysfunction(dysphagia) in stroke patients. Pharyngeal muscle group activity is important, because contracting muscles provide the driving force at the initiation of the swallow and generate the pressure gradients necessary for bolus movement into the esophagus. Although we have many treatment methods for dysphagia, electrical stimulation system will be useful for stroke patients having dysphagia. Electrical stimulation can be divided into the body stimulation and electrodes. The body stimulation is divided again into frequency counter, time control and current measurement part. These parts are to control the current intensity, frequency and stimulating time. And they can be variable according to the patient's clinical assessment. The electrode plays a role to deliver the current from the system to the muscle. Also the position of the electrode can be variable according to the treatment method. We performed the clinical experiment with the stroke patient who has swallowing disorder. The videofluoroscopy was used for the observation. From the result of clinical experiment based on electrical stimulation, we expected that the dysfunction(in pharynx) level of the patient can be improved. However we could not have enough effectiveness of the treatment because of the number of patients, patient's adaptation and treatment period. We will design the optimized electrical stimulation system based on enough clinical experiment in the future.

• 전기학회논문지
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• 제56권1호
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• pp.123-127
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• 2007

Up sizing of dye-sensitized solar cell(DSC) is the important technology to bring about commercialization of DSC. Several studies to obtain a stable large area DSC have been investigated in overseas laboratories, but have been hardly done in our country. In this study, up sizing technology of dye sensitized solar cells(DSCs) was investigated. We investigated low dark current materials for the current collecting grid. From the result, a new DSC module with metal grid was designed, and fabricated. For a new interconnection, both working and counter electrodes are alternately coupled on 10[cm]$\times$7[cm] substrate. We have achieved 68% of fill factor and photoelectric conversion efficiency of around 2.6% as the best results of new designed DSC structure.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2063-2066
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• 2005

This paper presents an approach to detect the dielectric condition of FRP Hot Stick in EHV high voltage cable whereas shutting down the power system is not necessary. The radio frequency generating method is adopted by transmitting radio wave into the Electrodes. This instrument is small, easy to use and also inexpensive. Furthermore, the impurity level of dirt on high voltage insulator (non-ceramic type) will be analyzed by using the methods based on IEEE Std.978-1984 at 105 kV.DC. /305 mm. and OSHA Regulation 1910.269 Part J - live line tools. The frequency at 10-20 MHz is applied to FRP Hot Stick via Electrode1 and from FRP Hot Stick surface to Electrode 2. After that the results will be evaluated by testing in each condition of FRP Hot Stick, such as dry surface, hot surface, foil winding and conductor inserting. Finally, the watt loss will be examined and compared with the loss from humidity and Carbon tracking. The important components of this system are radio frequency generating unit, frequency stabilizing unit, frequency amplifier, FRP Hot Stick frequency counter, processing unit, and display unit.

• 한국생산제조학회지
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• 제21권5호
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• pp.720-725
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• 2012

Sodium hypochlorite is used worldwide as a water disinfectant and in bleaching agent. Sodium hypochlorite applied to water initially undergoes hydrolysis to form free chlorine consisting of hypochlorous acid(HOCl) and hypochlorite ion($OCl^-$). For free chlorine determination, an electrochemical method is simple due to the electroactivity of free chlorine; it measures current and is free of most reagents. Amperometric free chlorine sensor has been developed with gold (Au)-based electrode. The 3-electrode free chlorine sensor whose working and counter electrodes were Pt exhibited excellent response to HClO at +400mV vs. Ag/AgCl/sat. KCl. In addition, the use of a pH error correction algorithm provided a reliable measurement of residual free chlorine in water sample without any pretreatment in the normal pH range(pH 6~8) of municipal water supply. The free chlorine sensor installed in on-line monitoring system could be used to continually monitor the level of residual free chlorine in real samples.

• 한국수소및신에너지학회논문집
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• 제24권5호
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• pp.401-412
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• 2013

The paper is to study on the simulation of the micro/macroscale thermo-electrochemical model of a single cell of anode-supported SOFC with direct internal reforming. The coupled heat and mass transport, electrochemical and reforming reactions, and fluid flow were simultaneously simulated based on mass, energy, charge conservation. The micro/macroscale model first calculates the detailed electrochemical and direct internal reforming processes in porous electrodes based on the comprehensive microscale model and then solve the macroscale processes such as heat and mass transport, and fluid flow in SOFCs with assumption of fully-developed flow in gas channel. The simulation results evaluate the overall performance by analyzing distributions of mole fraction, current density, temperature and microstructural design in co/counter flow configurations.