• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.53-60
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• 2017

Fluoroethylene carbonate (FEC) was studied as an additive for the electrolyte in lithium ion batteries with the $LiNi_{0.5}Mn_{1.5}O_4$ (LNMO) spinel cathode operating at a high potential beyond 4.7 V (vs. $Li/Li^+$). It was found that the FEC additive was electrochemically active for the $1^{st}$ charge cycle on the LNMO cathode. The presence of a large amount of FEC (more than 40 vol%) in the electrolyte caused severe side reactions with abnormally long voltage plateaus. In contrast, when the electrolyte contained less than 30 vol% FEC, the surface of the LNMO cathode was stabilized by the formation of the solid-electrolyte interphase (SEI), leading to improved cyclability. However, the resistance from the SEI limited the rate capability because of sluggish lithium transportation through the SEI and electronic insulation between the particles in the electrode.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.641-648
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• 2011

KEPRI (KEPCO Research Institute) designed and operated the lab-scale high temperature electrolysis (HTE) system for hydrogen production with $10{\times}10cm^2$ 5-cell stack at $750^{\circ}C$. The electrolysis cell consists of Ni-YSZ steam/hydrogen electrode, YSZ electrolyte and LSCF based perovskite as air side electrode. The active area of one cell is 92.16 $cm^2$. The hydrogen production system was operated for 2664 hours and the performance of electrolysis stack was measured by means of current variation with from 6 A to 28 A. The maximum hydrogen production rate and current efficiency was 47.33 NL/hr and 80.90% at 28 A, respectively. As the applied current increased, hydrogen production rate, current efficiency and the degradation rate of stack were increased respectively. From the result of stack performance, optimum operation current of this system was 24 A, considering current efficiencies and cell degradations.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.50-54
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• 2009

Ionizer is used for improving manufacturing process and reducing inferior goods in the clean room. As a general rule, neutralization of the electrostatic charge is most important to make TFT-LCD, PDP and OLED. Pulse AC-static eliminator with output voltage of about 10.5kV has been used these days as neutralization device. But this device has a problem with lower performance which was caused by particles-adhesion on the electrode when it has been used for a long time. So we studied to solve the problem with lower performance using high Frequency(72kHz) static eliminator which was produced by Piezo transformer device, and compared Pulse-AC type with Piezo-electronic device such as decay time and ion balance for 10 weeks periods. As a result of this study, we found that Piezo transformer device has been maintained normal condition for 10 weeks. Also, we made the rule by this study, normally Piezo transformer device has to clean the electrode during every 11th weeks.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.29-32
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• 2007

We analyzed the effect of cell resolution on the luminous efficacy through three-dimensional numerical simulation to understand the inherent discharge mechanism change in the plasma display panel. As the resolution increases from VGA to Full HD, the luminous efficacy decreases. With higher Xe content, VUV generation efficacy of Full HD becomes much lower than those of VGA or XGA cells, due to the increased plasma loss and lower electron heating. However a long electrode gap $140{\mu}m$ in Full HD cell with Ne-Xe [20%] results in the high luminous efficacy comparable to that of the XGA cell with $60{\mu}m$ gap. When comparing the effects of Xe content variation on the luminous efficacy of two different subpixel types, i. e., SDE (Segmented electrode in Delta color arrayed, Enclosed subpixel) [1] and conventional stripe barrier type in the XGA and Full HD cells, the luminous efficacy of SDE structure shows higher improvement in Full HD resolution compared with that of conventional type XGA cell, whose cause is identified as the reduced plasma loss.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.13-16
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• 2012

Zinc oxide (ZnO) films were deposited by an RF magnetron sputtering system with the RF power of 200W and 300W and flow rate of oxygen gases of 20 and 30 sccm, in order to research the growth of ZnO on carbon doped silicon oxide (SiOC) thin film. The reflectance of SiOC film on Si film deposited by the sputtering decreased with increasing the oxygen flow rate in the range of long wavelength. In comparison between ZnO/Si and ZnO/SiOC/Si thin film, the reflectance of ZnO/SiOC/Si film was inversed that of ZnO/Si film in the rage of 200~1000 nm. The transmittance of ZnO film increased with increasing the oxygen gas flow rate because of the transition from conduction band to oxygen interstitial band due to the oxygen interstitial (Oi) sites. The low reflectance and the high transmittance of ZnO film was suitable properties to use for the front electrode in the display or solar cell.

• Journal of the Korean Electrochemical Society
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• v.9 no.3
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• pp.132-134
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• 2006

The main component governing selectivity in ion-selective electrodes and optodes is the ionophore. For this reason, a member of natural products that possess selective ion-binding properties have long been sought after. By applying this principle, the performance of tetracycline used as neutral carriers for cation selective polymeric membrane electrode was investigated. The cation ion-selective electrode based on tetracycline gave a good Nernstian response of 26.6 mV per decade for calcium ion in the activity range $1x10^{-6}M$ to $1x10^{-2}M$ with and without lipophilic additives. The optimized cation ion-selective membrane electrodes displayed very comparable potentiometric responses to various mono and di-valent cations of alkali and alkaline earth metal ions except $Mg^{2+}$.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.224-230
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• 2012

Thermal batteries have excellent mechanical robustness, reliability, and long shelf life. Due to these characteristics as well as their unique activation mechanism, thermal batteries are widely adopted as military power sources. Li(Si)/$FeS_2$ thermal batteries, which are used mostly in these days, use LiCl-KCl and LiBr-LiCl-LiF as molten salt electrolyte. However, it is known that Li(Si)/$FeS_2$ thermal batteries have high internal resistance. Especially, $FeS_2$ cathode accounts for the greater part of internal resistance in unit cell. Many efforts have been put into to decrease the internal resistance of thermal batteries, which result in the development of new electrode material and new electrode manufacturing processes. But the applications of these new materials and processes are in some cases very expensive and need complicated additional processes. In this study, internal resistance study was conducted by adding carbon black and carbon nano-tube, which has high electron conductivity, into the $FeS_2$ cathode. As a results, it was found that the decrease of internal resistance of $FeS_2$ cathode by the addition of carbon black and carbon nano-tube.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1535-1537
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• 2003

Manganese oxide electrode was designed to improve electrical conductivity for dimensionally stable anode(DSA) using discreet variation (DV)-X${\alpha}$ method. It was calculated in DV-X${\alpha}$ method that the addition of nickel to manganese oxide reduce the energy band gap of manganese oxide electrode. Therefore, it is estimated that nickel in 3 additive elements of Ti, Ni and Sn is the best candidate to improve the electrical conductivity of manganese oxide. The anodically deposited manganese oxide which was produced in 0.2M $MnSO_4$ and 0.2M (Mn,Ni)$SO_4$ solution had $MnSO_4$ structure which was identified by XRD. The $MnSO_4$ films produced in both solutions over than 50mA/$cm^2$ of current density and long deposition time of 600sec showed low adhesion with Ti substrate.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.12-27
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• 2018

Supercapacitors (SCs) has gained an impressive concentration by the researchers due to its advantages such as high energy and power densities, long cyclic life, rapid charge-discharge rates, low maintenance and desirable safety. Hence it has been widely utilized in energy storage and conversion devices. Among the different components of SC, electrodes play a vital role in the performances of SCs. In this review, we present the recent advances in 2-D nanostructured metal nitrides, carbides, and phosphides based materials for SC electrodes. Finally, the electrochemical stability and designing approach for the future advancement of the electrode materials are also highlighted.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.2 s.161
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• pp.292-299
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• 2007

Development of portable device measuring the vital sign continuously with no limit of time and space is absolutely prerequisite for the U-health care that grafts the ubiquitous concept into medical system. Accordingly, it requires to develop a garment style apparatus for measuring vital-sign that is easy to wear on for a long time period. This study suggests a method to improve the insulation of electric cable and the skin adhesion of electrode by integrating the electric conductive material to garment, in order to develop a garment apparatus for measuring ECG for U-health care. Results of the research are as follows; In order to provide the adjacent conductive yarns with insulation, braid with narrow woven end was interlaced using polyester yarn. As a result, the direct contact between electric conductive yarns was restrained, which would be interposed into pin-tuck structured cable. Washable silicone gel applied around the electrode made of electric conductive fabric improved the adhesion, which prevents electrodes from dropping off from the skin surface during body movement. ECG signals on the human subject were tested using the garment apparatus developed by the above method. And the result was that the clear QRS wave formation in the typical form of ECG could be measured in both conditions of still and moving state as well. The result of this study is expected to contribute for the production of U-health care related medical apparatus by accelerating the practical uses of the garment measuring vital sign at a reasonable price.