• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권9호
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• pp.427-432
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• 2005

Ion migration characteristics of a rotary spark airgap of high voltage Pulse generator had been investigated. It was considered that the ion migration speed and the ions of the gases(atmosphere gases, $O_2,\;N_2,,\;and\;H_{2}O,\;etc$.) and the charged very fine particles(about $10\~100nm$ size) migrated through the upper stator ball and bottom stator ball of the rotary spark airgap would determined the rise and fall times of the output high voltage pulse. In this paper, a basic study on the ion migration characteristics of the rotary spark airgap between the spark stator ball and the ion-sensing electrode of the proposed high voltage pulse generator have been investigated experimentally. As a result, the three kinds of ion speeds were detected by the ion-sensing electrode installed at the position of the bottom stator ball of the ball type sparkgap high voltage pulse generator. The migration velocities, diameters, masses, charges, numbers of the ions and particles were obtained by experiments and calculations, which, however, would determine the rise and fall times of the output high voltage pulse.

• 대한화학회지
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• 제33권4호
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• pp.388-398
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• 1989

기체 감응막전극을 이용하여 수용액 중의 아질산이온을 연속${\cdot}$자동화법으로 정량하는 방법을 개발하였다. 이 방법에서 최종검출기로 쓴 이온선택성 전극은 관형 PVC막 pH 전극이었다. 장치계의 최적조건에서 구한 아질산이온 표준시료에 대한 전극의 감응기울기는 63.5mV/decade 이었으며, 직선감응 범위는 $2.5{\times}10^{-4}\; M{\sim}7.5 {\times} $10^{-2}$M 이었고, 검출한계는 $8.0{\times} 10^{-5}$M이었다. 이 방법은 다른 정량법보다 산성기체종의 방해를 적게 받을 뿐만 아니라 정량에 필요한 시간도 훨씬 단축할 수 있었다.

• 한국분말재료학회지
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• 제30권4호
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• pp.310-317
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• 2023

Small-film-type ion sensors are garnering considerable interest in the fields of wearable healthcare and home-based monitoring systems. The performance of these sensors primarily relies on electrode capacitance, often employing nanocomposite materials composed of nano- and sub-micrometer particles. Traditional techniques for enhancing capacitance involve the creation of nanoparticles on film electrodes, which require cost-intensive and complex chemical synthesis processes, followed by additional coating optimization. In this study, we introduce a simple one-step electrochemical method for fabricating gold nanoparticles on a carbon nanotube (Au NP-CNT) electrode surface through cyclic voltammetry deposition. Furthermore, we assess the improvement in capacitance by distinguishing between the electrical double-layer capacitance and diffusion-controlled capacitance, thereby clarifying the principles underpinning the material design. The Au NP-CNT electrode maintains its stability and sensitivity for up to 50 d, signifying its potential for advanced ion sensing. Additionally, integration with a mobile wireless data system highlights the versatility of the sensor for health applications.

• 대한전자공학회논문지
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• 제23권1호
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• pp.83-90
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• 1986

A micro pH-ISFET probe, which can be applied to the in vivo measurements of the hydrogen ion concentration in blood, has been developed, and a measuring system equiped with this probe also developed. The pH-ISFET has been fatricated by employing the techniques of integrated circuit fabrication. Two kinds of micro electrode formed around the sensing gate during the wafer process, and the other is a capillary type of Ag/AfCl/sat. KCI reduced in size. This capillary electrode has shown its good performance characteristics so far in the application with ISFET as well as a commercial one. In order to form a micro pH-ISFET probe, this pH-ISFET and well as a commercial one. In order to form a micro pH-ISFET probe, this pH-ISFET and the capillary electrode were built together into a needle tip having 1 mm inner diameter. The chip size of a twin pH-ISFET is 0.8 mmx1.4 mm, the material of the sensing gate membrane is Si3N4, and the sensitivity of the developed probe is about 52mV/pH.

• 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.

• 한국응용과학기술학회지
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• 제30권2호
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• pp.356-361
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• 2013

Lead (II) ion selective poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore as a sulfur containing sensing material is successfully developed. The electrode exhibits good linear response of 25.6 mV / decade (at $20{\pm}0.2^{\circ}C$, r2=0.995) within the concentration range of $1.0{\times}10^{-1}{\sim}4.0{\times}10^{-7}$ M Pb (II). The composition of this electrode was Ionophore : PVC : dioctylphthalate : potassiumtetrakis(4-chlorophenyl)borate : Oleic acid = 5.0 : 20.0 : 25.0 : 4.0 : 5.0. When we consider the results of using different composition electrodes based on only one potassiumtetrakis(4-chlorophenyl)borate or Oleic acid liphophlic additive, poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore with potassiumtetrakis(4-chlorophenyl)borate and Oleic acid liphophlic additive had the best result in response characteristics. The electrode shows good selectivity for lead (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.0 ~ 7.0 and their standard deviation in the measured emf differences was ${\pm}2.94$ mV at Tris buffered lead sample solution of $1.0{\times}10^{-2}$ M and ${\pm}2.82$ mV at Tris buffered lead sample solution of $1.0{\times}10^{-3}$ M. Their stabilization time was less than 710 s. and response time was less than 16 s.

• Journal of Biosystems Engineering
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• 제32권1호
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• pp.37-43
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• 2007

This study was carried out to investigate the applicability of PVC membrane-based ion-selective electrodes for macronutrients (K, Ca, and N) by measuring of potassium, calcium, nitrate ions in hydroponic nutrient solution. The capabilities of two ion-selective membranes with varying chemical compositions for each ion were evaluated in terms of sensitivity, selectivity, and lifetime to choose sensing elements suitable for measuring typical ranges of nutrient concentrations in hydroponic solutions. The selected calcium and nitrate ion-selective membranes showed effectively sensitive responses to calcium and nitrate ions with lifetimes of 25 and 15 days, respectively. The addition of a cation additive to the potassium membrane cocktail allowed its sensitivity to be increased whereas its lifetime was reduced from 30 days to 10 days.

• 청정기술
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• 제11권2호
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• pp.69-74
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• 2005

본 연구에서는 AFM 양극산화법을 이용하여 서브마이크로 수준의 패턴을 구성하였다. 자기조립법으로 제조한 MPTMS/Si(100) 기질 위에 AFM 양극산화법으로 패턴을 형성하였고, 비에칭법을 이용하여 아민그룹을 지닌 기능기를 고정시켰다. 금속전극으로는 Frens 방법으로 제조한 금나노입자를 이용하였다. 금속이온의 흡착에 따른 전도도는 근거리의 경우 coherent tunneling에 의존하지만, 원거리 전극에서는 incoherent tunneling에 의존한다. 전극의 간격이 가까울수록 저항이 감소하여 센서의 감도와 최소검출능을 개선할 수 있었다. 또한 다중기능성을 부여하여 센서의 선택도를 부여하였으며, 패턴의 크기에 따른 최소검출농도를 낮출 수 있음을 확인하였다.

• 대한화학회지
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• 제36권5호
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• pp.638-643
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• 1992

황화이온검출기로서 2가지 형태의 연속 flow-through 전극계의 분석적 감응성질을 조사하고, 최적조건에서 그들의 감응특성을 직접 비교하였다. 두 검출계에 있어서 측정한 봉우리전위를 황화이온농도의 대수값과 관련지웠으며, 적어도 시간당 20개의 시료를 정량할 수 있었다. pH전극법에서는 투석기를 지나 흘러가는 recipient stream의 pH를 측정하였다. 장치는 연속흐름형의 기체투석기가 관형 polymer 막전극과 연결되도록 설계되어 있다. 이 방법의 최적실험조건은 recipient $5.0 {\times} 10^{-5} M NaOH ＋ 5.0 {\times} 10^{-3} M$ NaCl과 diluent 0.10M $H_2SO_4$이며, recipient stream, diluent stream 및 시료의 유속은 모두 1.0ml/min이다. 황화이온 전극법에서는 시판하는 황화이온선택성 전극을 flow-through cell 속의 황화이온을 검출하는 데에 썼다. 이 방법의 최적실험조건인 황화이온 산화방지 완충제(1.0M NaOH 용액에 3.5g 아스코르브산과 7.6g $Na_2EDTA$를 용해)와 시료의 유속은 각각 1.4 ml/min와 1.0 ml/min이다.

• 폴리머
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• 제36권2호
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• pp.169-176
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• 2012

저항형 습도센서의 개발을 위하여 스크린 인쇄방법으로 glass epoxy(GE) 기재 위에 핑거의 수와 그 사이의 간격이 다른 여러 가지 바이트형의 금 전극을 제조하였다. 전극의 기본적인 구조는 핑거 수가 3, 4 및 5를 가지며 간격은 각각 310과 460 ${\mu}m$이다. 전극은 처음에 은 나노 페이스트로 전극 패턴을 인쇄하고 연속적으로 Cu, Ni 및 Au를 무전해 도금을 진행하여 제조하였다. 감습성 고분자 전해질은 [2-(methacryloyloxy)ethyl] dimethyl benzyl ammonium chloride(MDBAC)과 methyl methacrylate(MMA)의 공중합체를 사용하였으며 스크린 인쇄 방법으로 Au 전극/GE 기재 위에 인쇄하였다. 이렇게 제조된 습도 센서의 20-95%RH 영역의 상대습도 대 로그 임피던스 그래프에서 좋은 직선성을 보여주었으며 히스테리시스는 1.5%RH 이하 및 75초의 응답 및 회복 속도를 보여주었다. 전극의 구조는 고분자 저항형 습도센서의 감습특성에 큰 영향을 미치며 전해질 고분자와 전극 사이의 활성화 에너지, 온도의존성, 감도, 직선성 및 히스테리시스와 같은 감습특성 등의 차이를 비교하였고 특히 이온의 이동에 관여하는 활성화 에너지 및 온도 의존성에 큰 영향을 미쳤다.