• Title/Summary/Keyword: Cathodes

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Alq$_3$-based organic light-emitting devices with Al/fluoride cathode; Performance enhancement and interface electronic structures

  • Park, Y.;Lee, J.;Kim, D.Y.;Chu, H.Y.;Lee, H.;Do, L.M.;Zyung, T.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.105-107
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    • 2002
  • The device characteristics and the interface electronic structures of organic light-emitting devices based on tris-(8-hydroxyquinoline)aluminum were investigated with $Al/CaF_2$, Al/LiF, and Al-only cathodes. Similar to the Al/LiF cathode, the $Al/CaF_2$ cathode greatly improved the performance of the device over Al-only cathode. However, a photoelectron spectroscopy study revealed that despite the performance improvement, the evolution of the new peaks during $Al/CaF_2$ cathode formation closely resembled those of the Al-only cathode rather than the Al/LiF cathode.

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Development of Active Matrix Cathodes Composed of a-Si:H TFTs and Gated Molybdenum Field Emitter Arrays

  • Chung, Choong-Heui;Song, Yoon-Ho;Hwang, Chi-Sun;Ahn, Seong-Deok;Kim, Bong-Chul;Cho, Young-Rae;Lee, Jin-Ho;Cho, Kyoung-Ik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.1020-1023
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    • 2002
  • We successfully developed a-Si TFT controlled active matrix cathode (AMC) with gated Mo emitters. Also, we could remove emitter failures of the AMC through a novel surface treatment of Mo-tips, which indicates reduction of $MoO_3$ or chemical wet etching of $MoO_3$ by surface treatment. Transient behaviors of the AMC are strongly dependent on not only DC characteristics of device but also the device structure. Brightness and gray scale were well realized by low-voltage scan and data signals addressed to a-Si TFTs.

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Solid-Electrolyte Interphase in the Spinel Cathode Exposed to Carbonate Electrolyte in Li-Ion Battery Application: An ab-initio Study

  • Choe, Dae-Hyeon;Gang, Jun-Hui;Han, Byeong-Chan
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.169-169
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    • 2017
  • Due to key roles for the electrochemical stability and charge capacity the solid-electrolyte interphase (SEI) has been extensively studied in anodes of a Li-ion battery cell. There is, however, few of investigation for cathodes. Using first-principles based calculations we describe atomic-level process of the SEI layer formation at the interface of a carbonate electrolyte and $LiMn_2O_4$ spinel cathode. Furthermore, using beyond the conventional density functional theory (DFT+U) calculations we examine the work function of the cathode and frontier orbitals of the electrolyte. Based on the results we propose that proton transfer at the interface is an essential mechanism initiating the SEI layer formation in the $LiMn_2O_4$. Our results can guide a design concept for stable and high capacity Li-ion battery cell through screening an optimum electrolyte fine-tuned energy band alignment for a given cathode.

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Synthesis and Characterization of LSCF/CGO Composite Used as SOFC Cathode Materials (SOFC 용 LSCF/CGO 공기극의 제조 및 특성연구)

  • Park, Jae-Layng;Lim, Tak-Hyoung;Lee, Seung-Bok;Park, Seok-Joo;Shin, Dong-Ryul;Song, Rak-Hyun
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.184-186
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    • 2009
  • Composites of LSCF($La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ and CGO(gadolinium doped ceria) is an efficient candidate cathode material with CGO electrolytes. In this study, LSCF with exact perovskite structure was synthesized by using solid state reaction(SSR) method. The optimized temperature to synthesize $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ with rhombohedral structure. was $1100^{\circ}C$. The polarization resistance of the LSCF/CGO(50:50 wt.%) was smaller than those of other composite cathodes. The analysis of the EIS data of LSCF/CGO suggests that the diffusion and adsorption-desorption of oxygen can be the key process in the cathodic reaction of SOFC using LSCF/CGO as cathode material.

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One-pot Synthesis of Nickel and Tungsten Carbide Nanoparticles Supported Mesoporous Carbon Electrocatalyst for Oxygen Reduction Reaction (산소환원반응을 위한 니켈-텅스텐 카바이드 나노입자 담지 메조포러스 카본 촉매의 단일 합성 및 그 특성 평가)

  • Kim, Hyemin
    • Journal of the Korean institute of surface engineering
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    • v.51 no.3
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    • pp.179-184
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    • 2018
  • In this study, Ni and tungsten carbide (WC) nanoparticles are simultaneously synthesized with the mesoporous carbon nanoparticles (CNP) using a solution plasma processing (SPP) in the benzene. The Ni and WC nanoparticles were formed through the sputtering effect of electrodes during discharge, and mean time CNP were formed through reduction reaction. TEM observation showed that loaded Ni and WC nanoparticles were evenly dispersed on the CNP. The results of electrochemical analysis demonstrated that an introduction of Ni nanoparticles promoted to improve catalytic activity for oxygen reduction reaction (ORR). Moreover, Ni-WC/CNP lead to fast electron transfer process compared to that of WC/CNP. Therefore, the inexpensive Ni-WC/CNP might be a promising as catalytic material for cathodes in fuel cell applications.

High-temperature Oxidation of ZrO2/Al2O3 Thin Films (ZrO2/Al2O3 박막의 고온산화)

  • Park, Soon Young;Yadav, Poonam;Abro, Muhammad Ali;Lee, Dong Bok
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2014.11a
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    • pp.117-117
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    • 2014
  • Thin $ZrO_2/Al_2O_3$ films were deposited on a tool steel substrate using Zr and Al cathodes in a cathodic arc plasma deposition system (CAPD), and then oxidized at $600-900^{\circ}C$ in air for up to 50 h. They effectively suppressed the oxidation of the substrate up to $800^{\circ}C$ by acting as a barrier layer against the outward diffusion of the substrate elements and inward diffusion of oxygen. However, rapid oxidation occurred at $900^{\circ}C$ due mainly to the increased diffusion and subsequent oxidation of steel as well as the crystallization of amorphous $Al_2O__3$.

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Development of the Measurement System for the Multi-Functional DO Sensor (다기능 DO 센서용 계측시스템 개발)

  • 이동희;김태진;최복길
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.86-88
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    • 1996
  • A method is presented for the development of the PC-based measurement system on the 6 cathodes-single anode type multi-functional oxygen electrodes for detecting various components of the solution by measuring the dissolved oxygen(DO) concentration. The system is consisted with the 6 channel sensor signal modyfing circuits for the sensor and the PC interface circuits using the single chip microprocessor 80c196kc. Typical polarograms for the DO probes under test using this sensor circuits are presented. This system covers wide range of measuring time from 300sec to over 16 hour in one measurement step by programming the 9 monitor disply mode.

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Measurement of plasma temperature in hollow cathode discharge

  • Lee, Jun-Hoi;Yoon, Man-Young;Kim, Song-Kang;Park, Jae-Jun;Jeon, Byung-Hoon;Woo, Young-Dug
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.488-491
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    • 2002
  • We report the observation of line shapes in the optogalvanic spectrum, which are different from those of absorption, for transitions origination from the $3P_2$ ($1s_5$ in Paschen notation) metastable level of argon. The OG line shapes resemble those of absorption and be used to diagnose the characteristics of the discharge plasma. The measured plasma temperatures of Ar hollow cathode discharge for several metal cathodes are about 620~780K at discharge current of 7~10mA.

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Polarographic Studies on Electrochemical Reduction of p-Nitrosalicylic Acid and the Electrochemical Synthesis of p-Aminosalicylic Acid (p-nitrosalicylic acid의 전해환원에 의한 PAS의 합성과 Polarograph연구)

  • 김준용
    • YAKHAK HOEJI
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    • v.17 no.4
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    • pp.217-222
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    • 1973
  • Although a considerable amount of work has ben carried out, on the reduction of p-nitrosalicylic acid with Pb, Ni, Cu and Hg cathodes, published results do not proceeded the synthesis of p-aminosalicylic acid. In order to get the reduction potential and the mechanism of reduction, therefore, the electrode reactions occurring during "polarographic reduction" have been studied more fully. As a result, the author found that p-aminosalicylic acid (PAS) can be only produced in a HCl-ethanol solution using Sn cathode with the current density of 4.0A/$dm^{2}$, at 40-$50^{\circ}$.

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Study on Characteristics of Plasma in Hollow Cathode Discharge (Hollow Cathode Discharge에서 플라즈마 특성에 관한 연구)

  • Yoon, Man-Young;Shin, Jong-Soon
    • Journal of the Korean Graphic Arts Communication Society
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    • v.23 no.2
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    • pp.93-101
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    • 2005
  • The measured plasma temperature of Ar hollow cathode discharge for several metal cathodes are about $620\;{\sim}\;780K$ at discharge current of $7\;{\sim}\;10mA$. The optogalvanic signals were measured using hollow cathode discharge tube with argon as buffer gas at change of discharge currents. A change of ionization rate due to electron collision causes an increase or decrease of the electric conductivity. This change in electric conductivity generates the optogalvanic signal. We conclude that optogalvanic signal has close relation with the lowest metastable atoms density at low current.

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