• 전기학회논문지
• /
• 제58권6호
• /
• pp.1186-1193
• /
• 2009

Wearable ECG monitoring is regarded as one of the most essential part in the ubiquitous healthcare environment and subsequently day-life monitoring of a heart condition has been pursued especially for the elder people. However, there are many problems to accomplish this task such as; i) implementation of long-term monitoring device, ii) development of non-irritating electrode on skin and iii) stable signal acquisition. With these aims, we have focused on implementing a non-irritating electrode with an endurable monitoring device for day-life. To accomplish our tasks, we basically developed four different types of textile electrodes that are adapted by both shape and the composed material; flat or convex shape and Ag-conductive paste material or not. It turns out to be that a convex shape and Ag-paste textile electrode has the best performance in terms of both signal-to-noise ratio (SNR) and Impedance/Phase characteristics. Furthermore, ECG amplifier (35 ${\times}$ 35 mm) has developed to resolve the ECG signal and transfer the signal to desktop computing device or portable one by RF serial communication.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.115-115
• /
• 2012

반도체/디스플레이 산업분야의 발전으로 진공 공정 기술력 또한 증진되고 있다. 반도체소자의 초미세화, 진공부품의 대면적화가 진행 되면서 진공 공정 중에 발생하는 오염입자를 제어하는 것이 이슈가 되고 있다. 오염입자는 플라즈마의 물리적인 부식과 활성이 높은 화학반응에 의해 진공부품에서 부식이 진행되어 발생하며, 이는 반도체 및 디스플레이 부품의 신뢰성측면과 수율저하 등 life time의 근본적인 문제점으로 대두되고 있다. 본 연구에서는 반도체/디스플레이 장비용 코팅부품으로 많이 사용되고 있는 Al2O3 코팅막을 이용하였으며, sealing time에 따른 Anodic Aluminum Oxide (AAO) electrode의 물성특성평가 및 진공평가기술을 이용하여 life time을 예측하는 연구를 수행하였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
• /
• pp.525-526
• /
• 2006

One of the electrode in Haenam converter, which is role of rectifier in Jeju-Haenam HVDC system is destroyed and we found many cracks at another electrode and we also found many cracks in Jeju converter station, which is role of inverter of Jeju-Haenam. HVDC system, there is no exact reason for these phenomenon, even though the life cycle of these electrode is 40 years. So, the experts for HVDC system in KEPCO and Anotec corporation, which is manufacturer of electrode, would perform research for the reason of electrode disorder. In this paper analyze the reason of electrode disorder and corrosion in high voltage direct current system.

• Journal of Welding and Joining
• /
• 제33권2호
• /
• pp.47-55
• /
• 2015

With using adaptive control of the resistance spot welding machine, the advantage on electrode life time for galvanized steels has been addressed. This study was aimed to evaluate the electrode life time of galvanized steels with applying the constant current control and the adaptive control resistance spot welding process for a comparison purpose. The growth in diameter of electrode face was similar for both the constant current and the adaptive control up to 2000 welds. The button diameter was decreased with weld numbers, however, sudden increase in button diameter with use of the adaptive control after 1500 welds was observed. The peak load was continuously decreased with increasing number of welds for both the constant current and the adaptive control. The current compensation during a weld was observed with using the adaptive control after 1800 welds since the ${\beta}$-peak on dynamic resistance curve was detected at later weld time. The current compensation with adaptive control during resistance spot welding enhanced the nugget diameter at the faying interface of steel sheets and improved the penetration to thinner steel sheet.

• 대한환경공학회지
• /
• 제38권6호
• /
• pp.291-298
• /
• 2016

불용성 전극은 전기화학 공정에 있어 가장 핵심적인 소재이며, 이를 이용한 전기화학적 수처리 공정은 난분해성 물질을 제거하는 유용한 방법으로서 이에 대한 연구가 지속적으로 이루어져 오고 있다. 전기화학적 수처리 공정은 주로 산화전극에서의 산화반응과 환원전극에서의 환원반응을 이용하는 것이다. 본 연구에서는 불용성 전극의 제조공정에서 전처리 방법이 전극의 수명에 미치는 영향을 평가하였다. 실험결과 촉매전극층을 코팅하는 물질계 및 코팅방법을 동일하게 하는 경우에도 기판의 전처리 방법 즉, 기판표면의 조도, 세정방법, 중간층 형성 여부 및 방법 등에 따라 전극의 수명이 크게 달라지는 것을 확인하였다. 실험은 가장 많이 사용되는 전극의 하나인 $IrO_2/Ti$ 전극을 대상으로 하였다. 샌드 블라스팅 공정의 경우 입도를 달리하는 샌딩 미디어를 이용하여 전극을 제조하고 이에 대한 수명을 평가한 결과 #80알루미나(입도 $212{\sim}180{\mu}m$)를 이용하는 경우가 가장 효과적인 것으로 나타났다. 기판에 대한 세정 공정은 arc plasma를 이용하는 것이 가장 우수하였으며, 중간층을 형성함에 있어서는 스퍼터링법을 이용하여 Ta 계열의 중간층을 형성하는 방법을 적용하는 것이 가장 바람직한 것으로 확인되었다.

• 세라미스트
• /
• 제22권4호
• /
• pp.402-416
• /
• 2019

The development of next-generation secondary batteries, including lithium-ion batteries (LIB), requires performance enhancements such as high energy/high power density, low cost, long life, and excellent safety. The discovery of new materials with such requirements is a challenging and time-consuming process with great difficulty. To pursue this challenging endeavor, it is pivotal to understand the structure and interface of electrode materials in a multiscale level at the atomic, molecular, macro-scale during charging / discharging. In this regard, various advanced material characterization tools, including the first-principle calculation, high-resolution electron microscopy, and synchrotron-based X-ray techniques, have been actively employed to understand the charge storage- and degradation-mechanisms of various electrode materials. In this article, we introduce and review recent advances in in-situ synchrotron-based x-ray techniques to study electrode materials for LIBs during thermal degradation and charging/discharging. We show that the fundamental understanding of the structure and interface of the battery materials gained through these advanced in-situ investigations provides valuable insight into designing next-generation electrode materials with significantly improved performance in terms of high energy/high power density, low cost, long life, and excellent safety.

• 약학회지
• /
• 제39권2호
• /
• pp.113-117
• /
• 1995

Garlic tissue cells are employed for the conversion of L-asparagine into ammonia. An ammonia gas electrode is used as a detector. The effect of pH, buffer solution, temperature and life time of electrode to have used were investigated in order to optimize the electrode response. The combination of L-asparaginase in garlic tissue cells and the gas electrode response linearly to Lasparagine over the concentration range 1.0$\times$10$^{-4}$~1.0$\times$10$^{-1}$ M with a slope of 72.0 mV/decade and is selective with respect to other L-amino acids.

• Journal of Electrochemical Science and Technology
• /
• 제13권2호
• /
• pp.208-212
• /
• 2022

In this paper, we report the effects of temperature on the deterioration of graphite-based negative electrodes during the longterm cycling of lithium-ion batteries (LIBs). After cycling 75 Ah pouch-type LIB full cells at temperatures of 45℃ (45-Cell) and 25℃ (25-Cell) until their end of life, we expected to observe changes in the negative electrode according to the temperature. The thickness of the negative electrode of the cell was greater after cycling; that of the electrode of 45-Cell (144 ㎛) was greater than that of the electrode of 25-Cell (109 ㎛). Cross-sectional scanning electron microscopy analysis confirmed that by-products caused this increase in the thickness of the negative electrode. The by-products that formed on the surface of the negative electrode during cycling increased the surface resistance and decreased the electrical conductivity. Voltage profiles showed that the negative electrode of 25-Cell exhibited an 84.7% retention of the initial capacity, whereas that of 45-Cell showed only a 70.3% retention. The results of this study are expected to be relevant to future analyses of the deterioration characteristics of the negative electrode and battery deterioration mechanisms, and are also expected to provide basic data for advanced battery design.

• Journal of Biosystems Engineering
• /
• 제32권6호
• /
• pp.455-461
• /
• 2007

The electric current of a flow injection type enzyme-sensor was measured to confirm the stable operating conditions of the sensor. The current of the sensor was decreased as the buffer solution velocity increased. Under the limitation of the cycle time to be below 10 minutes, the effective ranges of the buffer solution velocity were suggested $0.10{\sim}0.26$, $0.12{\sim}0.24$, $0.1{\sim}0.25$ and $0.05{\sim}0.10\;cm/s$ of 1.0, 1.4, 2.4 and 3.4 mm of the electrode diameters, respectively. As the reaction time of the enzyme and the substrate was increased, the current was decreased because of the dilution between the sample and buffer solution. Therefore, it could be recommended that the reaction time was able to be selected as shortly as possible in consideration of the total cycle time. As the result of the experiments using a different volume ratio of the enzyme to substrate, it was concluded that the substrate had to be mixed with the same amount of the enzyme. The current have increased remarkably in proportion to the electrode diameter under 0.1 cm/s of the buffer solution velocity but there was no difference over 0.1 cm/s of the buffer solution velocity. The cross type arrangement of the electrode was highly suggested for application and machining of the sensor.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
• /
• pp.293-297
• /
• 2006

To receive size of same ground resistance by form of construction work of ground electrode, there is difference of amount or price of used resources, and should construct ground electrode little more effectively because appear to differ in life period according to nature of ground electrode resources, but should consider economical efficient.