• 제목/요약/키워드: Electronic transport

검색결과 907건 처리시간 0.023초

BCP 두께가 청잭 인광 OLED의 전기 및 광학적 특성에 미치는 영향 (Effects of BCP Thickness on the Electrical and Optical Characteristics of Blue Phosphorescent Organic Light Emitting Diodes)

  • 서유석;문대규
    • 한국전기전자재료학회논문지
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    • 제22권9호
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    • pp.781-785
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    • 2009
  • We have fabricated simple triple-layer blue-emitting phosphorescent organic light emitting diodes (OLEDs) using different thicknesses (25 and 55 nm) of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) electron transport layers. 1,1-bis[4-bis (4-methylphenyl)- aminophenyllcyclohexane (TAPC), bis[(4,6-di-fluorophenyl)-pyridinate-$N,C^{2'}$]picolinate (FIrpic) and N,N' -dicarbazolyl-3,5-benzene (mCP) were used as hole transport, blue guest and host materials, respectively. The driving voltage, electroluminescence (EL) efficiency and emission characteristics of devices were investigated. The maximum EL efficiency was 20 cd/A in the device with 55 nm BCP layer, which efficiency was about 33% higher than the device with 25 nm BCP layer. The higher efficiency in the 55 nm BCP device resulted from the enhanced electron-hole balance. In the EL spectrum of blue phosphorescent OLED with BCP layer, the relative intensity between 470 and 500 nm peaks was related to the location of emission zone.

$SF_6$-Ar 혼합기체에서의 전리와부착계수 (Ionization and Attachment Coefficients in Mixtures of $SF_6$ and Ar)

  • 김상남;하성철
    • 한국전기전자재료학회논문지
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    • 제14권9호
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    • pp.773-778
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    • 2001
  • In this dissertation the results of the combined experimental and theoretical studies designed to understand and predict the spatial growth and transport coefficients for electrons in SF$_{6}$ and SF$_{6}$-Ar mixtures have described. The ionization and attachment coefficients in pure SF$_{6}$ and SF$_{6}$-Ar mixtures have been calculated over the range of 10$_{6}$ molecule and for Ar atom proposed by other authors. The transport coefficients for electrons in (0.2%)SF$_{6}$-Ar and (0.5%)SF$_{6}$-Ar mixtures were measured by time-of-flight method, and the electron energy distribution function and the parameters of the velocity and the diffusion were determined by the variation of the collision cross-sections with energy. The results obtained in this work will provide valuable information on the fundamental haviors of electrons in weakly ionized gases and the role of electron attachment in the choice of better gases and unitary gas dielectrics or electro negative components in dielectric gas mixtures. gas mixtures.

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절연물 폴리머의 전하이동과 전계발광 (Charge transport and electroluminescence in insulating polymers)

  • 윤주호;최용성;이경섭
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.351-352
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    • 2007
  • Polymers submitted to thermo/electrical stress suffer from ageing that can drastically affect their functional behaviour. Understanding the physico/chemical processes at play during ageing and defining transport regimes in which these mechanisms start to be critical is therefore a prime goal to prevent degradation and to develop new formulation or new materials with improved properties. It is thought that a way to define these critical regimes is to investigate under which conditions (in terms of stress parameters) light is generated in the material by electroluminescence (EL). This can happen through impact excitation/ionization involving hot carriers or upon bi-polar charge recombination (a definition that excludes light from partial discharges, which would sign an advanced stage in the degradation process). After a brief review of the EL phenomenology under DC, we introduce a numerical model of charge transport postulating a recombination controlled electroluminescence. The model output is critically evaluated with special emphasize on the comparison between simulated and experimental light emission. Finally, we comment some open questions and perspectives.

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차폐층을 갖는 다층고온초전도 전력케이블의 전류분류 분석 (Analysis of Current Distribution of Multi-Layer HTSC Power Cable with a Shield Layer)

  • 이종화;임성훈;고석철;박충렬;한병성;황시돌
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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    • pp.535-538
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    • 2004
  • Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconduting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and AC loss. In this paper, the transport current distribution at conducting layers was investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer and compared with the case of without shield layer. The transport current distribution due to the pitch lenght was improved in the case of HTSC power cable with shield layer from the analysis.

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물류 수송을 위한 인터모달용 자동운송 대차의 주행정보 시스템 구축에 관한 연구 (A Study on The Establishment of A Driving Informaion System for An Intermodal Automatic Transport Bogie for Logistics Transportation)

  • 배거성;최헌진;손기환
    • 한국전자통신학회논문지
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    • 제17권1호
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    • pp.181-186
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    • 2022
  • 효율적인 물류 수송을 위한 수단으로 인터모달 자동운송 대차에 대한 요구가 있다. 인터모달은 이종 운송 수단과 연계, 특정 구간의 단선 운행에 대한 수요가 높은 특징을 가지고 있다. 본 연구에서는 인터모달 자동운송 대차 특징에 적합하도록 기존 철도 운행시스템과 달리 간소하면서도 인터모달 자동운송 대차에 최적화된 주행정보 시스템을 구현 및 실대형 시연모델에 적용하여 정위치 정차 및 각 시스템 간 원활한 인터페이스 및 간소화된 시스템으로 운용 사례를 제시한다.

TiO2를 전자수송층으로 적용하고 PMMA 절연층을 삽입한 용액공정 기반 양자점 전계 발광 소자의 활용 (Solution-Processed Quantum Dot Light-Emitting Diodes with TiO2 Nanoparticles as an Electron Transport Layer and a PMMA Insulating Layer)

  • 김보미;김정호;김지완
    • 한국전기전자재료학회논문지
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    • 제35권1호
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    • pp.93-97
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    • 2022
  • We report highly efficient quantum dot light-emitting diodes (QLEDs) with TiO2 nanoparticles (NPs) as an alternative electron transport layer (ETL) and poly (methyl methacrylate) (PMMA) as an insulating layer. TiO2 NPs were applied as ETLs of inverted structured QLEDs and the effect of the addition of PMMA between ETL and emission layer (EML) on device characteristics was studied in detail. A thin PMMA layer supported to make the charge balance in the EML of QLEDs due to its insulating property, which limits electron injection effectively. Green QLEDs with a PMMA layer produced the maximum luminance of 112,488 cd/m2 and a current efficiency of 25.92 cd/A. We expect the extended application of TiO2 NPs as the electron transport layer in inverted structured QLEDs device in the near future.

Bi-Te계 열전소재 성능 증대를 위한 Weighted Mobility Ratio 제어 (Control of Weighted Mobility Ratio to Enhance the Performance of Bi-Te-based Thermoelectric Materials)

  • 김민영;김현식;이규형
    • 마이크로전자및패키징학회지
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    • 제28권4호
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    • pp.103-107
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    • 2021
  • 좁은 밴드갭 반도체 특성을 나타내는 열전소재의 온도에 따른 전자전도 및 열전도 특성은 다수 캐리어 뿐 아니라 소수 캐리어의 전도 거동에 의해 결정된다. 따라서 소수 캐리어의 weighted mobility에 대한 다수 캐리어의 weighted mobility의 비율로 정의되는 weighted mobility ratio는 열전소재의 성능 증대에 매우 중요한 인자이다. 본 논문에서는 열전소재의 전자전도 현상에 대한 이론적인 고찰을 바탕으로 weighted mobility ratio 제어가 열전소재의 성능에 미치는 영향을 규명하여 고성능 Bi-Te계 열전소재 개발에 효과적으로 활용할 수 있는 소재 설계 지침을 제공하고자 한다.

차량과 보행자를 고려한 강화학습 기반 적응형 교차로 신호제어 연구 (Reinforcement Learning-Based Adaptive Traffic Signal Control considering Vehicles and Pedestrians in Intersection)

  • 김종민;김선용
    • 한국전자통신학회논문지
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    • 제19권1호
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    • pp.143-148
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    • 2024
  • 원활한 교통의 흐름은 현대 사회에서 매우 중요한 요소이며, 교통체증은 환경 및 경제 등 다양한 형태로 문제를 초래했다. 이러한 문제를 해결하기 위해 최근 인공지능을 활용한 지능형교통체계(Intelligent Transport System)가 주목받고 있다. 본 논문에서는 강화학습 기법을 활용하여 교차로 각 방향의 차량과 보행자를 동시에 고려하여 교통의 흐름을 원활하게 하면서 동시에 불만족도를 낮출 수 있는 알고리즘을 제안한다. 제안하는 알고리즘을 적용한 교차로 신호체계 시뮬레이션 결과, 기존의 고정형 신호체계에 비해 차량·보행자의 불만족도를 상당히 낮출 수 있으며, 교차로의 교차하는 도로의 수가 많을수록 성능의 차이가 증가함을 확인하였다.

A Study of Characteristic of Electrical-magnetic and Neutron Diffraction of Long-wire High-superconductor for Reducing Energy Losses

  • Jang, Mi-Hye
    • Transactions on Electrical and Electronic Materials
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    • 제9권6호
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    • pp.265-272
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    • 2008
  • In this paper, AC losses of long wire Bi-2223 tapes with different twist pitch of superconducting core were fabricated, measured and analyzed. These samples produced by a powder-in-tube method are multi-filamentary tape with Ag matrix. Also, it's produced by non-twist. The critical current measurement was carried out under the environment in Liquid nitrogen and in zero field by 4-prob method. And the Magnetic measurement was carried out under the environment of applied time-varying transport current by transport method. From experiment, the susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation. Neutron-diffraction measurements have been carried out investigate the crystal structure, magnetic structures, and magnetic phase transitions in Bi-2223([Bi, Pb]:Sr:Ca:Cu:O).

Determination of the Inelastic cross Sections for $C_{3}F_{8}$ Molecule by electron Swarm Study

  • Jeon, Byung-Hoon;Ha, Sung-Chul;Yang, Jeong-Mo
    • Transactions on Electrical and Electronic Materials
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    • 제2권1호
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    • pp.7-11
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    • 2001
  • We measured the electron transport coefficients, the electron drift velocity, W, and the longitudinal diffusion coefficient, $D_{L}$, over the E/N range from 0.03 to 100 Td and gas pressure range from 0.133 to 122 kPa in the 0.526% and 5.05% $C_{3}F_{8}$-Ar mixtures by the double shutter drift tube with variable drift distance. And we calculated these electron transport coefficients by using multi-term approximation of Boltzmann equation analysis. We determined the electron collision cross sections set for $C_{3}F_{8}$ molecule by the comparison of measurement and calculation. Our special attention in the present study was focused upon the inelastic collision cross sections of the $C_{3}F_{8}$ molecule.

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