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ISO 9705 Room-Corner Test & Model simulations (ISO 9705 Room-Corner Test와 모델 평가)

  • ;S.E. Dillom;J,G Quintiere
    • Fire Science and Engineering
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    • v.13 no.2
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    • pp.3-11
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    • 1999
  • New examination of a predictive model for the ISO 9705 room-corner test have been m made for materials studied by L S Fire Laboratories, Italy. The ISO 9705 test subjects wall a and ceiling mounted materials to a comer ignition source of 100 kW for a duration of 10 m minutes; if flashover does not occur this is followed by 300 kW for another 10 minutes. The m materials that did not stay in place during combustion because of melting, dripping, or d distorting were simulated by an adjustment to the material's total available energy. For m mat려als that remain in place the simulation model appears to do well in its prl어ictions. A l large-s떠Ie room test results 뾰 compar벼 with the m여el’s prediction also.

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A Fire Test Measuring the Heat Release Rate of Railway Car Interior Materials Satisfying the Korean Safety Guideline (안전기준을 만족하는 철도차량 내장재의 화재 열방출율 측정시험)

  • Park, Won-Hee;Lee, Duck-Hee;Jung, Woo-Sung
    • Fire Science and Engineering
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    • v.23 no.4
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    • pp.40-49
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    • 2009
  • A large-scale fire test was conducted for interior materials from a vehicle installed within a fire test room (ISO 9705). The interior materials are satisfying the Korean guideline for the safety of rail vehicles, where the guideline has taken effect since December 2004 in Korea. The output of ignition source (gas burner) was increased in several controlled steps. The objectives of this test are to assess the fire performance in terms of ignition and flame spread on interior lining materials and to provide data on an enclosure fires involving train interior materials that grow to flashover. These data will be used to develop and calibrate models for fire growth on the interiors of the railway vehicle.

Electrical Properties of a-IGZO Thin Films for Transparent TFTs

  • Bang, J.H.;Song, P.K.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.99-99
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    • 2010
  • Recently, amorphous transparent oxide semiconductors (TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). The TOS TFTs using a-IGZO channel layers exhibit a high electron mobility, a smooth surface, a uniform deposition at a large area, a high optical transparency, a low-temperature fabrication. In spite of many advantages of the sputtering process such as better step coverage, good uniformity over large area, small shadow effect and good adhesion, there are not enough researches about characteristics of a-IGZO thin films. In this study, therefore, we focused on the electrical properties of a-IGZO thin films as a channel layer of TFTs. TFTs with the a-IGZO channel layers and Y2O3 gate insulators were fabricated. Source and drain layers were deposited using ITO target. TFTs were deposited on unheated non-alkali glass substrates ($5cm{\times}5cm$) with a sintered ceramic IGZO disc (3 inch $\varnothing$, 5mm t), Y2O3 disc (3 inch $\varnothing$, 5mm t) and ITO disc (3 inch $\varnothing$, 5mm t) as a target by magnetron sputtering method. The O2 gas was used as the reactive gas. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of a-IGZO thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

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A Differential Index Assignment Scheme for Tree-Structured Vector Quantization (나무구조 벡터양자화 기반의 차분 인덱스 할당기법)

  • 한종기;정인철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.2C
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    • pp.100-109
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    • 2003
  • A differential index assignment scheme is proposed for the image encoding system in which a variable-length tree-structured vector quantizer is adopted. Each source vector is quantized into a terminal node of VLTSVQ and each terminal node is represented as a unique binary vector. The proposed index assignment scheme utilizes the correlation between interblocks of the image to increase the compression ratio with the image quality maintained. Simulation results show that the proposed scheme achieves a much higher compression ratio than the conventional one does and that the amount of the bit rate reduction of the proposed scheme becomes large as the correlation of the image becomes large. The proposed encoding scheme can be effectively used to encode R images whose pixel values we, in general, highly correlated with those of the neighbor pixels.

The Effect of Mutual Coupling between Current and Potential Test Leads on Ground Impedance (전류 및 전위 측정선간 상호유도가 접지임피던스에 미치는 영향)

  • Eom, Ju-Hong;Cho, Sung-Chul;Lee, Tae-Hyung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.7
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    • pp.1223-1228
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    • 2008
  • While a high frequency source is used for measuring the ground impedance, there are several factors having an effect on the measured value. A primary factor of the measurement error is the ac mutual coupling between current and potential test leads. The mutual coupling causes the test current to induce a voltage into the potential test lead that adds to the actual ground potential rise and produces a significant measurement error as the length of the test leads paralleled is prolonged. In order to avoid the mutual coupling, it is recommended that the ground impedance be measured by angled arrangement of test leads. The mutual impedance due to the inductive coupling with an angle of $90^{\circ}$ was calculated at $0^{\circ}$ by Campbell/Foster Method. With an angle of $180^{\circ}$, the mutual impedance was calculated large value enough to introduce a fairly large margin of error, however, the measured value of ground impedance was close to the value at $90^{\circ}$.

Improving the Overall Efficiency for DC/DC Converter with LoV-HiC System

  • Han, Dong-Hwa;Lee, Young-Jin;Kwon, Wan-Sung;Bou-Rabee, Mohammed A.;Choe, Gyu-Ha
    • Journal of Power Electronics
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    • v.12 no.3
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    • pp.418-428
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    • 2012
  • It is very important to improve the overall efficiency of systems with a source of power that has low-voltage high-current terminal characteristics such as fuel cells. A resonant converter is required for high efficiency systems. However, the peak value of the switches current is large in a resonant converter. This peak current requires a large number of switches and results in system failures. In this paper, an analysis and experiments of a resonant isolation push-pull converter are performed. A switching loss analysis is performed in order to compare losses between a resonant push pull converter and a hard switching push-pull converter. Specially, the conduction loss is studied based on the ratio between the resonant frequency and the switching frequency. In addition, a method for improving the efficiency is implemented with conventional HF insolation converters.

Temperature Distribution According to the Structure of a Conductive Layer during Joule-heating Induced Encapsulation for Fabrication of OLED Devices (OLED 소자 제조를 위한 주울 가열 봉지 공정 시 도전층 구조에 따르는 열분포)

  • Jang, Ingoo;Ro, Jae-Sang
    • Journal of Surface Science and Engineering
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    • v.46 no.4
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    • pp.162-167
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    • 2013
  • Encapsulation is required since organic materials used in OLED devices are fragile to water vapor and oxygen. Laser sealing method is currently used where IR laser is scanned along the glass-frit coated lines. Laser method is, however, not suitable to encapsulating large-sized glass substrate due to the nature of sequential scanning. In this work we propose a new method of encapsulation using Joule heating. Conductive layer is patterned along the sealing lines on which the glass frit is screen printed and sintered. Electric field is then applied to the conductive layer resulting in bonding both the panel glass and the encapsulation glass by melting glass-frit. In order to obtain uniform bonding the temperature of a conductive layer having a shape of closed loop should be uniform. In this work we conducted simulation for heat distribution according to the structure of a conductive layer used as a Joule-heat source. Uniform temperature was obtained with an error of 5% by optimizing the structure of a conductive layer. Based on the results of thermal simulations we concluded that Joule-heating induced encapsulation would be a good candidate for encapsulation method especially for large area glass substrate.

Analysis of Agricultural Working Load Experiments for Reduction Gear Ratio Design of an Electric Tractor Powertrain (전기구동 파워트레인의 감속기어비 설계를 위한 농용 트랙터의 작업 부하 분석)

  • Kim, Jung-Yun;Park, Yeong-Il
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.5
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    • pp.138-144
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    • 2012
  • Recent environmental issues such as exhaust gas and greenhouse effect make the agricultural machinery market takes into account the hybrid and electric propulsion technology used in automotive engineering. Generally the agricultural machinery, particularly an agricultural tractor, needs large load capacity and long continuous operating time comparing with conventional vehicles. In case of a pure electric tractor, it is necessary for considering large capacity batteries and long charging time. Therefore we take an AER extended PHEV (All Electric Range extended Plug-in Hybrid Electric Vehicle) power transmission system in developing an electric tractor in this study. First we propose a PHEV powertrain structure in order to substitute the conventional diesel engine equipped tractor. And we performed the road tests using a conventional mechanical tractor with various load conditions, which were classified and statistically treated real agricultural works. The test results were analysed with respect to the power characteristics of the power source. Finally using the test result, we designed two-stepped reduction gear ratios in the proposed an electric tractor powertrain for carrying out typical agricultural works.

Application and Effectiveness Analysis of SWAT Filter Strip in Golji Watershed (골지천 유역의 최적관리기법 적용에 따른 수질개선효과 분석)

  • Park, Youn Shik;Kwon, Jae Hyouk
    • Korean Journal of Environmental Agriculture
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    • v.33 no.1
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    • pp.30-36
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    • 2014
  • BACKGROUND: Best management practices are often implemented to control nonpoint source pollutants. Best management practices need to be simulated and analyzed for effective Best management practices implementations. Filter strip is one of effective Best management practices in agricultural areas. METHODS AND RESULTS: Soil and Water Assessment Tool model was selected to explore the effectiveness of filter strip to control total phosphorous in Golji watershed. Soil and Water Assessment Tool model was calibrated for flow and total phosphorous by Sequential Uncertainty Fittin ver.2 algorithm provided in Soil and Water Assessment Tool-Calibration and Uncertainty Procedures. Three scenarios defined by filter strip width were applied. The filter strip width of 5 m was able to reduce the most amount of total phosphorous. In other words, the total phosphorous reduction by filter strip of 5 m was 28.0%, while the reduction was 17.5% by filter strip of 1 m. However, the reduction per unit filter strip width were 17.4%, 8.0%, and 4.5% for 1 m, 3 m, and 5 m of filter strips, respectively. CONCLUSION: Best management practices need to be simulated and analyzed so that the BMP scenario can be cost-effective. A large size of BMP might be able to control large amount of pollutants, however it would not be indicated as a cost-effective strategy.

The progresses of superconducting technology for power grid last decade in China

  • Xiao, Liye;Gu, Hongwei
    • Progress in Superconductivity and Cryogenics
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    • v.17 no.1
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    • pp.1-5
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    • 2015
  • With the increasing development of renewable energy, it is expected that large-scale renewable power would be transported from the west and north area of China to the east and south area. For this reason, it will be necessary to develop a wide-area power grid in which the renewable energy would be the dominant power source, and the power grid will be faced by some critical challenges such as long-distance large-capacity power transmission, the stability of the wide-area power grid and the land use problem for the power grid. The superconducting technology for power (STP) would be a possible alternative for the development of China's future power grid. In last decade, STP has been extensively developed in China. In this paper, we present an overview of the R&D of STP last decade in China including: 1) the development of high temperature superconducting (HTS) materials, 2) DC power cables, 3) superconducting power substations, 4) fault current limiters and 5) superconducting magnetic energy storage (SMES).