• Title/Summary/Keyword: Thermal Conductivity

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Electromagnetic and Thermal Analysis of PRAM cell with phase change material (상변화 재료의 물질상수에 따른 PRAM cell의 전자장 및 열 해석)

  • Jang, Nak-Won;Kim, Hong-Seung;Lee, Seong-Hwan;Mah, Suk-Bum
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.144-145
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    • 2007
  • Phase change random access memory is one of the most promising candidates for next generation non-volatile memories. However, the high reset current is one major obstacle to develop a high density PRAM. One way of the reset current reduction is to develop the new phase change material. In this paper, to reduce the reset current for phase transition, we have investigated the effect of phase change material parameters using finite element analysis.

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The Study on Aged Sleeves for Old Transmission Lines (정상시공된 가공송전선 접속개소에서의 전류에 따른 온도변화 거동)

  • Kim, Byung-Geol;Kim, Shang-Shu;Ahn, Sang-Hyun;Sohn, Hong-Kwan;Park, In-Pyo;Lee, Dong-Il;Jang, Tae-In
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.518-519
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    • 2007
  • In this paper, the temperature distribution within ACSR conductor was precisely measured and examined, conducted as part of a serious of studies on large currents in transmission lines. According to measurements of the conductor temperature near a joint(sleeve and clamp), the electrical resistance of joint is lower than that of the same length conductor. The detailed results were presented in the text.

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Generation of Water and Steam Properties for LWR

  • Jun, Byung-Jin;Lee, Chang-Kun;Lee, Ji-Bok;Chang, Jong-Hwa
    • Nuclear Engineering and Technology
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    • v.12 no.3
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    • pp.180-193
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    • 1980
  • Subroutines to enable fast and accurate generation of water properties-enthalpy, specific volume, viscosity, thermal conductivity and saturation entropy-which are usually basic requirements for nuclear calculation of LWR, have been developed. The sources of data were quoted from “ASME Steam Tables (1967)” and their Revision (1975). It is ensured that the obtained values from this routine fall within 0.2% difference compared with the reference data, in the ranges of temperature and pressure for LWR nuclear calculation.

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IRRADIATION EFFECTS OF HT-9 MARTENSITIC STEEL

  • Chen, Yiren
    • Nuclear Engineering and Technology
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    • v.45 no.3
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    • pp.311-322
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    • 2013
  • High-Cr martensitic steel HT-9 is one of the candidate materials for advanced nuclear energy systems. Thanks to its excellent thermal conductivity and irradiation resistance, ferritic/martensitic steels such as HT-9 are considered for in-core applications of advanced nuclear reactors. The harsh neutron irradiation environments at the reactor core region pose a unique challenge for structural and cladding materials. Microstructural and microchemical changes resulting from displacement damage are anticipated for structural materials after prolonged neutron exposure. Consequently, various irradiation effects on the service performance of in-core materials need to be understood. In this work, the fundamentals of radiation damage and irradiation effects of the HT-9 martensitic steel are reviewed. The objective of this paper is to provide a background introduction of displacement damage, microstructural evolution, and subsequent effects on mechanical properties of the HT-9 martensitic steel under neutron irradiations. Mechanical test results of the irradiated HT-9 steel obtained from previous fast reactor and fusion programs are summarized along with the information of irradiated microstructure. This review can serve as a starting point for additional investigations on the in-core applications of ferritic/martensitic steels in advanced nuclear reactors.

Boron Nit ride Nanotube Synthesis and Applications (보론 나이트라이드 나노튜브 합성 및 응용기술)

  • Cho, Hyun Jin;Kim, Jun Hee;Kim, Myung Jong
    • Vacuum Magazine
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    • v.3 no.3
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    • pp.19-23
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    • 2016
  • BNNTs (Boron nitride nanotubes) is an analogue of CNTs (Carbon Nanotubes) in terms of lattice structure. In BNNTs, a boron atom forms sp2 hybridized bonding with three nitrogen atoms, and so does a nitrogen with three boron atoms in the honeycomb structure. Its innovative properties, such as high thermal conductivity, neutron shielding capability, superb oxidation resistance at $900^{\circ}C$, excellent chemical resistance, and superior mechanical properties are advantageous for a wide range of applications, especially for electric device packages, neutron shielding, protective coating materials, and functional composites. In this paper, boron nitride nanotube synthesis, properties and application are reviewed.

Forming of Metallic Bipolar Plates by Dynamic Loading (Dynamic Load를 이용한 박막 금속 분리판 성형기술)

  • Koo, J.Y.;Kang, C.G.
    • Transactions of Materials Processing
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    • v.21 no.1
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    • pp.5-12
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    • 2012
  • The weight of the bipolar plate is one of the crucial aspects of improving power density in PEMFC stacks. Aluminum alloys have good mechanical properties such as density, electrical resistivity, and thermal conductivity. Furthermore, using aluminum in a bipolar plate instead of graphite reduces the bipolar plate cost and makes machining easier. Therefore in this study, an aluminum alloy was selected as the appropriate material for a bipolar plate. Results from feasibility experiments with the aim of developing fuel cells consisting of Al bipolar plates with multiple channels are presented. Dynamic loading was applied and the formability of micro channels was estimated as a function of punch pressure and die radius. Sheets of Al5052 with a thickness of 0.3mm were used. For a die radius of 0.1mm the formability was optimized with a sine wave dynamic load of 90kN at maximum pressure and 5 cycles of a sine wave punch travel. The experimental results demonstrate the feasibility of the proposed manufacturing technique for producing bipolar plates.

Calculation of Material Properties with JMatPro for the Process Simulation (JMatPro를 이용한 공정해석에서의 물성계산)

  • Lee, Kyung-Hoon;Kang, Gyeong-Pil
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.142-145
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    • 2008
  • Process simulation requires accurate and reliable data for a wide variety of material properties, ranging from thermal conductivity to flow stress curves. Traditionally such data are gathered from experimental sources, which has significant disadvantages in that not all of the required data is readily available, it may be from various sources that are themselves inconsistent, measurement of high temperature properties is expensive, and furthermore the properties can be sensitive to microstructure as well as to alloy composition. This article describes the development of a new multi-platform software program called JMatPro, which is based on CALPHAD methodology, for calculating the properties and behavior of multi-component alloys. A feature of the JMatPro is that the calculations are based on sound physical principles rather than purely statistical methods. Thus, many of the shortcomings of methods such as regression analysis can be overcome.

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Development of Cooling System for Electronic Devices using Oscillating Capillary Tube Heat Pipe (진동세관형 히트파이프를 이용한 전자기기 냉각에 대한 연구)

  • Kim Jong-Soo;Ha Soo-Jung
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.4
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    • pp.436-442
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    • 2005
  • Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. In this paper, characteristics on oscillating heat pipe according to operating conditions (environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated From the experimental results $25^{\circ}C$(environment temperature) R-141b (working fluid) $40\%$ (charging ratio) was best performace at others of inclination angle and the top heating mode of OCHP performed $80\%$ efficiency of the bottom heating mode.

Development of tactile sensor and its application (촉각센서 개발 및 응용)

  • 김종호;이정일;이효직;박연규;김민석;강대임
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.9
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    • pp.21-25
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    • 2004
  • 최근 국가의 10대 신성장 동력산업에 포함 되어 있는 RT(robot technology)는 향후 포스트 반도체산업의 중요한 산업으로 국내 경제를 활성화 시키는 원동력이 될 것으로 전망된다. 이와 더불어 향후에는 현재의 산업용 로봇이 아닌 감각과 지능을 가진 인간친화적인 로봇이 출현할 것으로 기대된다. 즉 주변 환경을 인지하여 정보를 획득하고 지능적 판단, 행위 및 상호작용을 통하여 인간을 지원하는 지능형 로봇은 인간과의 상호작용을 통하여 감성을 이해하며 서비스 제공, 인간의 동작이나 작업을 지원 그리고 위험작업 수행, 인간이 불가능한 작업을 대신 할 수 있을 것이다. (중략)

Effect of Sealing on Thermal Conductivity of Aluminium Anodic Oxide layer (실링처리가 알루미늄 양극산화피막의 열전도도에 미치는 영향)

  • Lee, Jeong-Hun;Kim, Yong-Hwan;Kim, Ji-Hong;Jeong, Won-Seop
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.329-329
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    • 2012
  • 알루미늄 합금은 기존에는 경량소재로써 각광을 받아왔지만, 최근에는 다양한 전자 및 기계 부품에서 방열이 크게 대두 됨에 따라 방열 소재로써의 관심이 증가하고 있다. 알루미늄 합금의 고유한 표면처리법인 양극산화에의해 생성되는 산화층의 열전도도에 대한 연구를 실시하였다. 또한, 이들 산화층은 실리이라는 후처리에 의해서 기공구조의 변화가 일어나는데, 이 실링 처리가 열전도도에 미치는 영향에 대해서 확인해 보았다. 양극 산화피막의 미세 기공층이 비어있는 경우에 비해서 실링에 의해서 기공이 산화물 및 수산화물로 채워진 경우 열전도도가 증가하였다. 또한, 산화층의 기공률에 따라서 열전도도가 증가되는 비율의 차이가 발생하였다.

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