• Title/Summary/Keyword: Bottom emission

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Effects of Fuel Injection Conditions on Combustion Characteristics of a DI Diesel Engine (직접분사식 디젤 엔진에서 연료 분사 인자에 따른 연소 특성)

  • Kook, Sang-Hoon;Yu, Jun;Park, Cheol-Woong;Bae, Choong-Sik
    • 한국연소학회:학술대회논문집
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    • 2002.06a
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    • pp.33-38
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    • 2002
  • An optical single cylinder diesel engine equipped with a common-rail injection system has been built to investigate diesel combustion and emission characteristics. Three optical widows (piston crown quartz for bottom view of the cylinder, upper piston quartz for allowing laser sheet and liner quartz for side view) have been placed in the optical engine to visualize spray characteristics and combustion process inside the cylinder. Before doing further research using various optical diagnostics with the optical engine, fundamental combustion experiments and flame visualization incorporating a high speed motion analyser have been carried out with a wide range of engine operating conditions.

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High performance top-emitting OLEDs with copper iodide-doped hole injection layer

  • Lee, Jae-Hyun;Leem, Dong-Seok;Kim, Jang-Joo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.492-495
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    • 2008
  • Efficient top-emitting organic light-emitting diodes were fabricated using copper iodide (CuI) doped NPB as a p-doped hole injection layer to improve hole injection from a silver bottom electrode. The enhanced hole injection is originated from the formation of the charge transfer complex between CuI and NPB. The devices result in high efficiency of 69 cd/A with almost Lambertian emission pattern.

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휘도 향상용 ZnS 나노 렌즈 제작 및 OLED 소자의 전기·광학적 특성 연구

  • Yun, Dang-Mo;Kim, Il-Gu;Jo, Song-Jin;Kim, Mi-Yeong;Lee, Seung-Hyeon;Lee, Beom-Ju;Lee, Su-Hyeong;Lee, Chung-Hun;Sin, Jin-Guk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.391.1-391.1
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    • 2014
  • 광물질로 인광물질을 사용한 유기발광다이오드(Organic Light Emitting Diode, OLED)는 재결합에 의해 형성된 여기자를 발광에 모두 이용할 수 있기 때문에 내부 양자효율이 100%로 알려져 있다. 하지만 유기층에서 발생된 빛이 소비자에게 전달되기까지의 경로에서 발생되는 wave guiding effect로 인해, 발생된 빛의 20%만이 전달된다. 특히 bottom emission type의 OLED에서 glass와 air사이의 굴절률이 달라 발생되는 전반사에 의해 손실되는 빛의 양은 35%에 달한다. 따라서 본 연구에서는 glass와 air사이의 전반사를 줄이고 광추출을 위해 습식 방법으로 hemisphere type의 ZnS를 제작하였다. 제작된 ZnS는 직경 200nm까지 성장하였으며, 이렇게 제작된 ZnS nano lens가 적용된 OLED device에서 휘도가 20% 이상 향상되는 것을 확인하였다.

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External cost Forecasting of Virtual Point Source in Suwon Area Using Impact Pathway Analysis - A Comparison of Suwon to Paris - (영향경로해석을 이용한 수원시 가상 점오염원의 외부비용 예측 - 수원시와 파리시 비교분석을 중심으로 -)

  • Jeong, Sang Jin
    • Journal of Environmental Impact Assessment
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    • v.14 no.5
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    • pp.291-303
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    • 2005
  • Impact pathway analysis(IPA) is a bottom-up approach to estimates health and environmental risks from emissions of classical pollutants (eg. $PM_{10}$, $SO_2$, $NO_x$ and CO). The model starts from the emission rates of facility, calculates the yearly mean concentrations of pollutants at the ground level using atmospheric dispersion models. After this, proper epidemiological exposure-response functions are applied to determine the impact on the receptors. Finally the methodology can monetise the calculated physical impact on the basis of selected economic evaluation. The aim of this study is to evaluate an external cost of virtual point source in Suwon area using IPA. The results shows minor modification of local input data can make it possible to apply the model to Suwon area.

Effects of the Method of Changing Compression Ratio on Engine Performance in an SI Engine (가솔린 엔진에서 압축비 변경 방법이 성능에 미치는 영향)

  • 이원근;엄인용
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.27-33
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    • 2001
  • In this study, it is observed that the distribution of combustion chamber volume affects the volumetric efficiency. The distribution ratio was adjusted by controlling combustion chamber volume of head and piston bowl one. Four cases were investigated, which are the combination of different distribution ratios and different compression ratios (9.8-10.0). A commercial SOHC 3-valve engine was modified by cutting the bottom face of the head and/or replacing the piston by the one that has different volume. The result shows that the less the head side volume, the more volumetric efficiency is achieved under the same compression ratio. It is also observed that increasing volumetric efficiency results in early knock occurrence due to increased "real" compression ratio. To consider reliability in estimating the volumetric efficiency, we examined the sensitivity of the AFR equation to possible errors in emission measurements. It is shown that the volumetric efficiency, which is calculated by measuring AFR and fuel consumption, can be controlled in 1% error. 1% error.

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Barix Multilayer Barriers; a key enabler for protecting OLED displays and flexible organic devices

  • Moro, L.L.M.;Rutherford, N.;Chu, X.;Visser, R.J.;Graf, G.C.;Gross, M.E.;Bennet, W.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.616-619
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    • 2005
  • OLED display are extremely sensitive to water and oxygen. Developing a thin film encapsulation for this technology has for a long time been elusive. Vitex has developed a multilayer barrier consisting of alternating inorganic and organic layers which can meet the requirements for a successful protection for such displays. In this paper we will discuss the basic process, the model, the results on top and bottom emission OLED displays as well as the application of Barix layers on plastic to create flexible OLED displays. We will show that for displays all the requirement for the telecommunication industry can be met and that the we can scale up to a mass manufacturing process.

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Metal nano-wire fabrication and properties (금속 나노와이어의 제조와 특성)

  • Hamrakulov, B.;Kim, In-Soo
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.432-434
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    • 2009
  • Metal nano-wire arrays on Cu-coated seed layers were fabricated by aqueous solution method using sulfate bath at room temperature. The seed layers were coated on Anodic aluminum oxide (AAO) bottom substrates by electrochemical deposition technique, length and diameter of metal nano-wires were dominated by controlling the deposition parameters, such as deposition potential and time, electrolyte temperature. Anodic aluminum oxide (AAO) was used as a template to prepare highly ordered Ni, Fe, Co and Cu multilayer magnetic nano-wire arrays. This template was fabricated with two-step anodizing method, using dissimilar solutions for Al anodizing. The pore of anodic aluminum oxide templates were perfectly hexagonal arranged pore domains. The ordered Ni, Fe, Co and Cu systems nano-wire arrays were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Vibrating Sample Magnetometer (VSM). The ordered Ni, Fe, Co and Cu systems nano-wires had different preferred orientation. In addition, these nano-wires showed different magnetization properties under the electrodepositing conditions.

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An Analysis of Renewable Portfolio Standard Impact using DECADES Program (DECADES 프로그램을 활용한 신재생에너지 의무할당제 효과 분석)

  • 오영진;노재형;김발호;박종배
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.5
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    • pp.275-284
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    • 2004
  • This paper analyzes the environmental impact and economic effect of introducing the Renewable Portfolio Standard (RPS) into Korean electricity market using the DECADES (Database and Methodologies for Comparative Assessment of Different Energy Source for Electricity Generation) model, a comparative assessment tool developed by IAEA. A bottom up approach is adopted for the evaluation of air pollutant emission and its impact of several RPS scenarios. The environmental damage costs of RPS scenarios are evaluated based on the Extern-E results and Thailand externality study carried by EGA T. The results of this study can be applied in determining or analyzing the national electricity policy and energy policy.

Analysis of the Economic and Environmental Effects of Renewable Portfolio Standards with DECADES

  • Rbo Jae-Hyung;Chung Koo-Hyung;Kim Balho H.
    • KIEE International Transactions on Power Engineering
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    • v.5A no.1
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    • pp.70-78
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    • 2005
  • This paper analyzes the environmental impact and economic effect of introducing the Renewable Portfolio Standard (RPS) into the Korean electricity market using the DECADES (Database and Methodologies for Comparative Assessment of Different Energy Sources for Electricity Generation) model, a comparative assessment tool developed by IAEA. A bottom up approach is adopted for the evaluation of air pollutant emission and its impact of several RPS scenarios. The environmental damage costs of RPS scenarios are evaluated based on the Extern-E results and the Thailand externality study carried out by EGAT. The results of this study can be applied in determining or analyzing the national electricity policy and energy policy.

Synthesis of Nano-Sized Y3Al5O12:Ce3+ Phosphors Prepared by High Energy Beads Milling Process and Their Luminescence Properties

  • Song, Hee-Jo;Kim, Dong-Hoe;Park, Jong-Hoon;Han, Byung-Suh;Hong, Kug-Sun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.386-386
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    • 2012
  • For white light emitting diode (LED) applications, it has been reported that Y3Al5O12:Ce3+ (YAG:Ce) in nano-sized phosphor performs better than it does in micro-sized particles. This is because nano-sized YAG:Ce can reduce internal light scattering when coated onto a blue LED surface. Recently, there have been many reports on the synthesis of nano-sized YAG particles using bottom-up method, such as co-precipitation method, sol-gel process, hydrothermal method, solvothermal method, and glycothermal method. However, there has been no report using top-down method. Top-down method has advantages than bottom-up method, such as large scale production and easy control of doping concentration and particle size. Therefore, in this study, nano-sized YAG:Ce phosphors were synthesized by a high energy beads milling process with varying beads size, milling time and milling steps. The beads milling process was performed by Laboratory Mill MINICER with ZrO2 beads. The phase identity and morphology of nano-sized YAG:Ce were characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. By controlling beads size, milling time and milling steps, we synthesized a size-tunable and uniform nano-sized YAG:Ce phosphors which average diameters were 100, 85 and 40 nm, respectively. After milling, there was no impurity and all of the peaks were in good agreement with YAG (JCPDS No. 33-0040). Luminescence and quantum efficiency (QE) of nano-sized YAG:Ce phosphors were measured by fluorescence spectrometer and QE measuring instrument, respectively. The synthesized YAG:Ce absorbed light efficiently in the visible region of 400-500 nm, and showed single broadband emission peaked at 550 nm with 50% of QE. As a result, by considering above results, high energy beads milling process could be a facile and reproducible synthesis method for nano-sized YAG:Ce phosphors.

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