• 제목/요약/키워드: science and engineering research operation

검색결과 1,042건 처리시간 0.039초

연속 ECR-CVD 조업하에 RF-magnetron-sputter의 싸이클조업을 통해 PET위에 올려진 구리박막의 특성 (Characteristic of Copper Films on PET Substrate Deposited by Cyclic Operation of RF-magnetron-sputtering Coupled with Continuous Operation of ECR-CVD)

  • 명종윤;전법주;변동진;이중기
    • 한국재료학회지
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    • 제15권7호
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    • pp.465-472
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    • 2005
  • Preparation of copper film on PET substrate was carried out by cyclic operation of RF-magnetron­sputtering under continuous operation of ECR-CVD. The purpose of this study is aimed to an increase in deposition rate with keeping excellent adhesion between copper film and PET. In order to optimize the sputtering time under continuous ECR-CVD, cyclic operation concept is employed. By changing parameters of cyclic operation such as split of e and cycle time of A, the characteristics and thickness of the deposited copper film are controlled. As $\theta$ value increase, film thickness could confirm to increase and its surface resistivity value decreases. The highest adhesive strength appears at $\theta=0.33$ and cycle time of 30 min. The uniformity of copper film shows $5\%$ in our experimental range.

High Temperature Size Exclusion Chromatography

  • Cho Hee-Sook;Park Soo-Jin;Ree Moon-Hor;Chang Tai-Hyun;Jung Jin-Chul;Zin Wang-Cheol
    • Macromolecular Research
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    • 제14권3호
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    • pp.383-386
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    • 2006
  • High temperature size exclusion chromatography (SEC) has been used widely for the characterization of crystalline polymers, for which high temperature operation above the polymer melting temperature is required to dissolve the polymers. However, this high temperature operation has many advantages in SEC separation in addition to merely increasing polymer solubility. At high temperature the eluent viscosity decreases, which in turn decreases the column backpressure and increases the diffusivity of the analytes. Therefore, many reports on the high temperature operation of high performance liquid chromatography (HPLC) have focused on shortening the analysis time and enhancing the resolution. However, the application of high temperature SEC analysis to exploit the merits of high temperature operation is scarce. In this article, therefore, we report on a new apparatus design for high temperature SEC.

Korea Pathfinder Lunar Orbiter (KPLO) Operation: From Design to Initial Results

  • Moon-Jin Jeon;Young-Ho Cho;Eunhyeuk Kim;Dong-Gyu Kim;Young-Joo Song;SeungBum Hong;Jonghee Bae;Jun Bang;Jo Ryeong Yim;Dae-Kwan Kim
    • Journal of Astronomy and Space Sciences
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    • 제41권1호
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    • pp.43-60
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    • 2024
  • Korea Pathfinder Lunar Orbiter (KPLO) is South Korea's first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft's initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.

Frequency Dependency of Multi-layer OLED Current Density-voltage Shift and Its Application to Digitally-driven AMOLED

  • Kim, Hyunjong;Kim, Suhwan;Hong, Yongtaek
    • Journal of the Optical Society of Korea
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    • 제16권2호
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    • pp.181-184
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    • 2012
  • We report, for the first time, operation frequency dependence of current density-voltage ($J_{OLED}-V_{OLED}$) shift for multi-layer organic light-emitting diodes (OLEDs). When the OLEDs were electrically stressed for 21 hours with 50% duty voltage pulses at 60, 120, 240, and 360 Hz, the JOLED-VOLED shifts were suppressed by half for 360 Hz operation compared with 60 Hz operation, but with little change in emission efficiencies. This frequency dependent $J_{OLED}-V_{OLED}$ shift is believed to be commonly observed for typical multi-layer OLEDs and can be used to further improve lifetime of digitally-driven active-matrix OLED displays.

A Performance Comparison between Operation Strategies for Idle Vehicles in Automated Guided Vehicle System

  • Kim, Kap-Hwan;Kim, Jae-Yeon
    • 한국경영과학회지
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    • 제23권2호
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    • pp.67-81
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    • 1998
  • An Automated Guided Vehicle System (AGVS) with a unidirectional loop guide path is modeled as a discrete-time stationary Markov chain. It is discussed how to estimate the mean response time, the utilization, and the cycle time of AGV for a delivery order. Three common operation strategies for idle vehicles - central zone positioning rule, circulatory loop positioning rule and point of release positioning rule - are analyzed. These different operation strategies are compared with each other based on the performance measures.

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A New Modified CNP for Autonomous Microgrid Operation Based on Multiagent System

  • Kim, Hak-Man;Wei, Wenpeng;Kinoshita, Tetsuo
    • Journal of Electrical Engineering and Technology
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    • 제6권1호
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    • pp.139-146
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    • 2011
  • This paper presents a new modified Contract Net Protocol (CNP) for microgrid operation based on multiagent system. The CNP is a widely used protocol for interactions among distributed problem solving. The Contract Net Interaction Protocol of the Foundation for Intelligent Physical Agents (FIPA-CNIP) is a minor modification of the original CNP for multiagent system applications. In this paper, a modified CNP (MCNP) based on the FIPA-CNIP is proposed for more specialized interactions among agents for microgrid operation. A multiagent system is designed and constructed for microgrid operation. A microgrid operation based on the multiagent system is tested to check the functionality of the proposed MCNP.

DEA를 활용한 국가별 글로벌 기술협력 수준 분석 : OECD 국가를 중심으로 (Using DEA to Analyze the Degree of Global Technology Cooperation at the National Level)

  • 이민국;이성주
    • 한국경영과학회지
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    • 제41권2호
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    • pp.67-80
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    • 2016
  • Under a rapidly changing environment, firms have attempted to co-operate with organizations that possess high technologies to improve their technical capabilities. Most countries have worked towards developing a suitable strategy for international technology co-operation based on the diagnostic results of their technological capabilities and indices. These diagnostic results indicate the level and degree of international technology co-operation that have been developed in academia. However, identifying the overall conditions of international technology co-operation based on existing indices is a difficult task. Hence, to address this problem, indices that can measure diverse perspectives of core technology co-operation activities need to be developed. This research aims to develop a framework for identifying the current state of international technology co-operation in diverse perspectives at the national level. We develop indices based on relevant literature and formulate an analytical framework for international technology co-operation in diverse perspectives using DEA analysis. The results are expected to contribute to effective technology planning at the national level by diagnosing capabilities for international technology co-operation from diverse perspectives.