• Title/Summary/Keyword: Organic LED

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Pay Per Click Marketing Strategies: A Review of Empirical Evidence

  • Bhandari, Ravneet Singh
    • The Journal of Industrial Distribution & Business
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    • v.8 no.6
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    • pp.7-16
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    • 2017
  • Purpose - Today's world revolves around search engines which are the driving force behind any marketer. The thirst for marketing has led to the evolution of online 'Pay per click' over last few years and is the most widely used instrument. Research design, data, and methodology - Exploratory research design highlights many marketing variables getting affected by pay per click marketing. To analyze the said phenomenon, the data was gathered through questionnaire from the sample of 338 respondents which were selected by simple random sampling method mostly from the National Capital Region (NCR) of Delhi in India. The data collected from the respondents was loaded on SAS base for exploratory factor analysis and multiple regression analysis. Results - Pay per click as a marketing tool has significant impact on the consumers. The most prominent factors of pay per click marketing identified in the research are Ad quality, Competition, Targeting, Trend and Budget. Conclusions - Organic as well as inorganic ads, keeping in mind the end goal to gage the exchange of these two postings in the marked look territory. Additionally, here we dissected supported pursuit promotions in all. It would be beneficial to break down the impact of promotion position on the pay per click marketing.

Determination of photo- and electroluminescence quantum efficiency of semiconducting polymers (전기발광고분자의 양자효율 측정)

  • 이광희;박성흠;김진영;진영읍;서홍석
    • Korean Journal of Optics and Photonics
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    • v.13 no.2
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    • pp.128-133
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    • 2002
  • In a recent effort to develop polymer light-emitting diodes (LEDs) as promising flat panel display components, measurements of reliable absolute photoluminescence (PL) and electroluminescence (EL) efficiency for polymer materials are required. In this work, we performed the measurement of PL and EL efficiency of luminescent polymers using an integrating sphere technique. The external PL efficiency of MEH-PPV was estimated to be 8 ($\pm$2)% together with the value of 0.02 1m/W for the external EL efficiency. This PL efficiency is in good agreement with published values, indicating that our PL efficiency measurements are somewhat legitimate. We believe this study might contribute to the research and development of organic materials for optoelectronic devices.

Solution-Processible Blue-Light-Emitting Polymers Based on Alkoxy-Substituted Poly(spirobifluorene)

  • Lee, Jeong-Ik;Chu, Hye-Yong;Oh, Ji-Young;Do, Lee-Mi;Lee, Hyo-Young;Zyung, Tae-Hyoung;Lee, Jae-Min;Shim, Hong-Ku
    • ETRI Journal
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    • v.27 no.2
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    • pp.181-187
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    • 2005
  • Alkoxy-substituted poly(spirobifluorene)s and their copolymers with a triphenylamine derivative have been synthesized by Ni(0)-mediated polymerization. The polymers were well soluble in common organic solvents. Pure blue-light emissions without the long wavelength emission of poly(fluorene)s have been observed in the fluorescence spectra of polymer thin films. The light emitting diodes with a device configuration of ITO/PEDT:PSS(30 nm)/polymer(60 nm)/LiF(1 nm)/Al(100 nm) have been fabricated. The electroluminescence spectra showed the blue emissions without the long wavelength emission as observed in the fluorescence spectra. The relatively poor electroluminescence quantum yield of the homopolymer (0.017% @ 20 $mA/cm^{2}$) with color coordinates of (0.16, 0.07) has been improved by the introduction of triphenylamine moiety, and the copolymer with derivative exhibited an electroluminescence quantum yield of 0.15 % at 20 $mA/cm^{2}$ with color coordinates of (0.16, 0.08). Moreover, the introduction of polar side chains to the spirobifluorene moiety enhanced the device performance and led to the quantum yields of 0.6 to 0.7 % at 20 $mA/cm^{2}$, although there was some expense of color purities.

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Responses of weed community and soil biota to cessation of fertilization

  • Eo, Jin-U
    • Journal of Ecology and Environment
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    • v.33 no.4
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    • pp.317-323
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    • 2010
  • Nutrient availability is a critical component of agroecosystems, and is relevant to both above- and below- ground interactions. The principal objective of this study was to determine how the cessation of fertilization affects the communities of weeds and soil organisms in a corn/wheat field. Changes in dominant weed species, substrate-induced respiration, and the population density of nematodes and microarthropods were evaluated. Microbial substrate-induced respiration (SIR) and the population density of microarthropods decreased following the cessation of fertilization and were partly correlated with the aboveground weed biomass. The cessation of organic fertilizer application but continuing application of inorganic fertilizer reduced the population density of nematodes. In response to the cessation of fertilization, weed communities were dominated by species with little dependency on fertilization. Amaranthus retroflexus was identified as the most dominant species in the corn field; however, it was replaced by Digitaria ciliaris after the cessation of fertilization. In the wheat field, the cessation of fertilization led to a rapid reduction in the biomass of most weeds, except for Vicia angustifolia, supposedly as the result of symbiotic nitrogen fixation. Additionally, the fact that weed biomass was partially correlated with SIR or the population density of microarthropods may reflect a mutual feedback between soil organisms and weeds. The results indicate that the cessation of fertilization alters communities of weeds and soil organisms through changes in weed biomass and interactions with symbiotic microorganisms.

New Phosphorescent Cyclometalated Iridium(III) Complexes with Diphenyl-1,3-oxazolic and 2-(3-Thienyl)pyridine Ligands for LED Applications

  • Kirsyuk, V. V.;Turgambaeva, A. E.;Shim, Jung-Jin;Rhee, Shi-Woo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.174-177
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    • 2003
  • We report four new phosphorescent iridium(III} complexes with 2,4-diphenyl-1,3-oxazole [$Ir(24dpo)_3$], 2,5-diphenyl-1,3-oxazole [$Ir(25dpo)_3$], 2-(3-thienyl) pyridine [$Ir(3thpyh)_3$] and [Ir(3thpy)2(acac)]. Three of them demonstrate good photophysical properties to be used as dopants to organic polymer matrix or to be used "as is" without a host matrix to fabricate OLEDs. Green and yellow light emission was observed for the photoluminescence: 569/525, 549/498 nm and 557,604/533 (solid state/$CH_2Cl_2$ solution) for $Ir(24dpo)_3$, $Ir(3thpyh)_3$ and $Ir(3thpyh)_2$acac respectively. Room temperature luminescent lifetimes are 2.5 and 1.8 ${\mu}s$ and quantum efficiencies 37 and 53%for $Ir(24dpo)_3$ and $Ir(3thpyh)_3$. The complexes are stable in air and sublimable at low pressure without considerable decomposition. Comparison of physicochemical properties of the reported iridium(III) cyclometalated compounds with that known from literature is carried out.

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Modeling and Identification of Web Tension Control System with Dancer Roll (댄서롤이 장착된 웹 장력 제어시스템의 모델링 및 규명)

  • Lee, Sang-Hwa;Lee, Jeh-Won;Lee, Hyuk-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.11
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    • pp.70-76
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    • 2009
  • Web tension control system recently have been applied to OLED(Organic Light-Emitting Diode), RFID of flexible material, e-Paper and PLED(Polymeric LED) and various web control algorithms have being developed for higher productivity and product quality These system need an accuracy model to design and implement controller. In this paper, the web tension control system with dancer roll is mathematically modeled. Mathematical model consists of 8 subsystems and each subsystems can be described as impedance structure which connected by velocity and tension. Mathematical model is different from the estimated model at high frequency range because of structure dynamics which is ignored on mathematical model. The estimated model is derived using ARMAX model. The controller is designed using the estimated model. The step response of the estimated model are compared with that of physical model for a validation of estimated model. The experimental results show a good match between them.

Stripping of Fe(III) from the Loaded Mixture of D2EHPA and TBP with Sulfuric Acid Containing Reducing Agents

  • Liu, Yang;Nam, Sang-Ho;Lee, Manseung
    • Bulletin of the Korean Chemical Society
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    • v.35 no.7
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    • pp.2109-2113
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    • 2014
  • Solvent extraction of Fe(III) from chloride solution by using a mixture of D2EHPA (Di-(2-ethylhexyl)-phosphoric acid) and TBP (Tri-butyl phosphate) and the reductive stripping of Fe(III) from the loaded organic were investigated. Quantitative extraction of Fe(III) from the solution (Fe concentration = 90 g/L) was accomplished in two cross-current extraction stages by using the mixture of D2EHPA and TBP. In order to facilitate the stripping efficiency, a reductive stripping method was employed by using $H_2SO_3$ or $Na_2SO_3$ as a reducing agent. The addition of $H_2SO_4$ into reducing agents led to improvement in the stripping efficiency while high concentration acid would suppress it. Both of the mixtures of $H_2SO_4+H_2SO_3$ and $H_2SO_4+Na_2SO_3$ showed good efficiency for the stripping of Fe(III), while the latter was recommended as the stripping solution based on the economics and experimental condition.

Isolation of Compounds having Inhibitory Activity toward Tyrosinase from Receptaculum Nelumbinis (연방(蓮房)의 티로시나제 저해 활성을 보이는 성분분리)

  • Cho, Hyun Woo;Jung, Won Seok;An, Byeong Gwan;Cho, Jung Hee;Jung, Su Young
    • Korean Journal of Pharmacognosy
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    • v.44 no.1
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    • pp.1-5
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    • 2013
  • Nelnumbo nucifera Gaerth. (Nymphaeaceae) has been used in a korean traditional medicine to treat fever, sunstroke and dizziness. The receptaculums of this plant were refluxed with MeOH, and then fractionated with organic solvents ($CH_2Cl_2$, EtOAc and n-BuOH) to screen whitening activity using tyrosinase inhibitory activity. EtOAc ($IC_{50}$, 45.23 ${\mu}g/ml$) fractions showed a good tyrosinase inhibitory activity. Column chromatographic separation of $CH_2Cl_2$ and EtOAc fractions of Receptaculum nelumbinis led to the isolation 3 compounds. Their chemical structures were characterized as ${\beta}$-sitosterol (1), quercetin 3-O-${\beta}$-D-galactopyranoside (2) and kaempferol 3-O-${\beta}$-D-glucopyranoside (3) by comparison NMR spectral data and with those in references, respectively. Isolated compounds 1 and 3 were firstly isolated from Receptaculums nelumbinis. Compounds 2 and 3 showed potent whitening activities.

Synthesis and Properties of Polyimide Composites Containing Graphene Oxide Via In-Situ Polymerization

  • Zhu, Jiadeng;Lee, Cheol-Ho;Joh, Han-Ik;Kim, Hwan Chul;Lee, Sungho
    • Carbon letters
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    • v.13 no.4
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    • pp.230-235
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    • 2012
  • In this study, reduced graphene oxide/polyimide (r-GO/PI) composite films, which showed significant enhancement in their electrical conductivity, were successfully fabricated. GO was prepared from graphite using a modified Hummers method. The GO was used as a nanofiller material for the preparation of r-GO/PI composites by in-situ polymerization. An addition of 20 wt% of GO led to a significant decrease in the volume resistivity of composite films by less than nine orders of magnitude compared to that of pure PI films due to the electrical percolation networks of reduced GO created during imidization within the films. A tensile test indicated that the Young's modulus of the r-GO/PI composite film containing 20 wt% GO increased drastically from 2.3 GPa to 4.4 GPa, which was an improvement of approximately 84% compared to that of pure PI film. In addition, the corresponding tensile strength was found to have decreased only by 12%, from 113 MPa to 99 MPa.

AZO 박막 위에 전기화학증착법에 의해 제작된 ZnO 나노로드의 전기 및 광학적 특성

  • Ju, Dong-Hyeok;Lee, Hui-Gwan;Yu, Jae-Su
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.101-101
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    • 2011
  • 투명전도성산화물(transparent conducting oxides, TCOs) 박막으로써 널리 쓰이는 산화인듐주석(indium tin oxide, ITO)은 전기 전도성과 광 투과성이 우수하여 주로 유기발광다이오드(organic light-emitting diode, OLED)의 전극, 발광다이오드(light-emitting diode, LED)의 current spreading 층 및 태양전지(solar cell)의 윈도우층(window layer) 등의 광전자 소자로 응용되고 있으나, 고가의 indium 가격과 인체에 유해한 독성 등이 문제점으로 지적되고 있다. 따라서 indium의 함량을 저감한 새로운 조성의 TCO 또는 indium을 함유하지 않은 친환경적인 TCO 대체 재료 개발의 필요성이 증대되고 있다. 이러한 재료 중 하나인 AZO (Al-doped zinc oxide, $Al_2O_3$: 2 wt.%)는 3.82eV의 넓은 에너지 밴드갭을 가지며, 가시광선 및 근 적외선 파장 영역에 대하여 90% 이상의 높은 투과율을 나타낸다. 또한, 습식식각이 가능하며, 매우 풍부하여 원가가 매우 저렴하고, 독성이 없다. 본 연구에서는 박막 증착율이 높고, 제작과정의 조정이 용이한 RF magnetron 스퍼터를 이용하여 glass 기판 위에 AZO 박막을 성장하고, $N_2$ 분위기에서 다양한 온도 조건에서 열처리(rapid thermal annealing, RTA)하여 전기 및 광학적 특성에 대하여 비교 분석하였다. 또한, 이후에 기존의 성장방법과 달리 고가의 진공 장비를 사용하지 않고, 저온에서도 간단한 구조의 장비를 이용하여 균일한 나노구조를 성장시킬 수 있는 전기화학증착법(electrochemical deposition)으로 AZO 박막위에 ZnO 나노로드를 다양한 성장조건에 따라 성장시켜 광학적 특성을 비교 분석하였다.

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