• Title/Summary/Keyword: Heating material

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Experimental fabrication and analysis of thermoelectric devices (복합재료에 의한 열전변환 냉각소자의 개발에 관한 연구)

  • 성만영;송대식;배원일
    • Electrical & Electronic Materials
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    • v.9 no.1
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    • pp.67-75
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    • 1996
  • This paper has presented the characteristics of thermoelectric devices and the plots of thermoelectric cooling and heating as a function of currents for different temperatures. The maximum cooling and heating(.DELTA.T) for (BiSb)$\_$2/Te$\_$3/ and Bi$\_$2/(TeSe)$\_$3/ as a function of currents is about 75.deg. C, A solderable ceramic insulated thermoelectric module. Each module contains 31 thermoelectric devices. Thermoelectric material is a quaternary alloy of bismuth, tellurium, selenium, and antimony with small amounts of suitable dopants, carefully processed to produce an oriented polycrystalline ingot with superior anisotropic thermoelectric properties. Metallized ceramic plates afford maximum electrical insulation and thermal conduction. Operating temperature range is from -156.deg. C to +104.deg. C. The amount of Peltier cooling is directly proportional to the current through the sample, and the temperature gradient at the thermoelectric materials junctions will depend on the system geometry.

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A Numerical Algorithm for Modeling Microwave Heating Effects in Electrically Large Structures (A 전기적인 대구조의 마이크로파 가열의 수치해석 모델링)

  • Braunstein, Jeffrey;Lee, Ha-Young;Kim, Hyeong-Seok
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2315-2317
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    • 2005
  • In this paper, an iterative method to model the electromagnetic heating of electrically large lossy dielectrics is presented. Frequency domain finite element (FEM) solutions of the wave equation are determined for the lossy inhomogeneous dielectric as the material properties are change with temperature and time. The power absorbed from microwave losses is applied to a finite element time domain (FETD) calculation of the heat diffusion equation. Time steps appropriate for updating the piecewise material properties in the wave equation and the time stepping of the heat equation are presented. The effects of preheating and source frequency are investigated.

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The SAG Behavior of Overhead Conductor due to Forest Fire (산불에 의해 가열된 가공송전선의 이도거동)

  • Kim, Byung-Geol;Kim, Shang-Shu;Jun, Wan-Gi;Han, Se-Won;Kim, Jin-Han
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.516-517
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    • 2007
  • Because forest fire can give a serious damage to overhead conductors, the thorough understanding about sag behavior of burned conductor is very important in maintaining the transmission line safely. Therefore, a systematic investigation was carried out by heating method. As the heating temperature increases, drastic change of tensile strength of Al wire due to the softening of Al wire occurred. When Al wire is exposed to the flame(about $800^{\circ}C$) during only 13 seconds, the remained tensile strength of Al wire showed under 90%. and then sag of overhead conductor become deteriorated. The detailed results will be given in the text.

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Electrical Fire Identification due to Conductor Structure Analysis of Electrical Wires (전선의 도체조직 분석에 의한 전기화재 감식)

  • Park, O-Cheol;Kim, Wang-Kon;Park, Nam-Kyu;Hong, Jin-Woong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.615-618
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    • 2003
  • To investigate the electrical fire identification due to conductor structure analysis of an electrical wire, we are studied by temperature heating test, over current test, short test and electric molten marks. And metal structure analysis of wire by short, we are found out increase in crystal grain with heating temperature. Structure of specimen at over current 300[%] occurred hardly structure formation and boundary of grain.

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The Aging Behavior of Overhead Conductor due to Forest Fire (산불에 의한 가공송전선의 열화거동)

  • Kim, Byung-Geol;Kim, Shang-Shu;Jun, Wan-Gi;Han, Se-Won
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.534-535
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    • 2007
  • Because forest fire can give a serious damage to overhead conductors, the thorough understanding about aging behavior of burned conductor is very important in maintaining the transmission line safely. Therefore, a systematic investigation was carried out by heating method. As the heating temperature increases, drastic change of tensile strength of Al wire due to the softening of Al wire occurred. When Al wire is exposed to the flame(about $800^{\circ}C$) during only 13 seconds, the remained tensile strength of Al wire showed under 90%. The detailed results will be given in the text.

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Low temperature preparation of $SnO_2$ films by ICP-CVD (ICP-CVD를 이용한 $SnO_2$ 박막 저온 증착)

  • Lee, H.Y.;Lee, J.J.
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2007.04a
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    • pp.157-158
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    • 2007
  • Tin oxide films were successfully crystallized without additional heating by inductively coupled plasma assisted chemical vapor deposition (ICP-CVD). The degree of crystallization was affected by the ICP power, hydrogen flow and ion bombardment induced by negative substrate bias. The substrate temperature was increased only up to $150^{\sim}180^{\circ}C$ by plasma heating, which suggests that the formation of $SnO_2$ crystalswas caused by enhanced reactivity of precursors in high density plasma. The hardness of deposited tin oxide films ranged from 5.5 to 11GPa at different hydrogen flow rates.

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Temperature-Dependent Thermal and Chemical Stabilities as well as Mechanical Properties of Electrodeposited Nanocrystalline Ni

  • Zheng, Liangfu;Peng, Xiao
    • Metals and materials international
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    • v.24 no.6
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    • pp.1293-1302
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    • 2018
  • Nanocrystalline (NC) Ni electrodeposits (EDs) with a mean grain size of $34{\pm}12nm$ has been investigated, from room temperature to $800^{\circ}C$ under a purge gas of argon, by both non-isothermal and isothermal differential scanning calorimetry measurements, in combination with characterization of temperature-dependent microstructural evolution. A significant exothermic peak resulting from superimposition of recrystallization and surface oxidation occurs between 340 and $745^{\circ}C$ at a heating rate of $10^{\circ}C/min$ for the NC Ni EDs. The temperatures for recrystallization and oxidation increase with increasing the heating rate. In addition, recrystallization leads to a profound brittle-ductile transition of the Ni EDs in a narrow range around the peak temperature for the recrystallization.

A Study on the Aging characteristics of EPDM by Heating cycle (Heating Cycle에 의한 EPDM의 열화 특성에 대한 연구)

  • Choi, N.H.;Yu, S.D.;Han, S.O.;Yoon, J.Y.;Park, K.S.;Kim, J.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.177-179
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    • 1997
  • 본 연구에서는 최근 그 사용이 급증하고 있는 옥외용 절연재료에 대한 열화특성을 평가하기 위하여 펄렛상태의 EPDM 원 시료를 Hot plate를 이용하여 씨트로 제작하였다. 기후조건에 대응하는 열 싸이클에 의해 절연재료에 일어나는 화학적, 전기적 특성변화를 조사하기 위하여 주기적인 열싸이클을 가하면서 일정 기간별로 유전특성과 표면누설전류 및 표면의 화학적 변화에 대하여 측정하였다. 또한 접촉각 측정을 통하여 EPDM의 전기적 화학적 열화 또는 성질 변화에 대하여 검토하였다. 측정 결과 EPDM은 비교적 단기간의 열싸이클에 대해서 전기적 화학적 특성변화는 그다지 나타나지 않는 것으로 나타났다.

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The rapid synthesis of $MoSi_2$ for high-temperature furnace heating elements

  • Soh, Dea-Wha;Natalya, Korobova
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.38-41
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    • 2001
  • The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The influence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of $MoSi_2$ during SHS might be different and depending on experimental conditions.

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The rapid synthesis of MoSi$_2$ for high-temperature furnace heating elements

  • Soh, Deawha;Korobova, Natalya
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.38-41
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    • 2001
  • The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The inf1uence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of MoSi$_2$ during SHS might be different and depending on experimental conditions.

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