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材料热阻系数取值对10kV三芯电缆导体温度计算的影响 被引量:1
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作者 陈浩然 胡倩楠 《广东电力》 2014年第4期86-90,共5页
为了在10 kV三芯电缆导体温度实时计算中规范材料热阻系数的取值,通过三芯电缆导体至表面的传热关系进行三芯电缆各层结构材料热阻系数归一化灵敏度计算,分析各层结构材料热阻系数取值准确度对导体温度的不同影响。以计算结果为基础,设... 为了在10 kV三芯电缆导体温度实时计算中规范材料热阻系数的取值,通过三芯电缆导体至表面的传热关系进行三芯电缆各层结构材料热阻系数归一化灵敏度计算,分析各层结构材料热阻系数取值准确度对导体温度的不同影响。以计算结果为基础,设计在不同敷设环境下的多组阶跃升流实验;结合实验数据,利用ANSYS有限元进行不同变量情况下的导体温度变化仿真分析。结果表明,导体温度对填充层及内护套材料热阻系数灵敏度最为敏感,灵敏度会随导体电流增大而增大;空气敷设下的灵敏度高于土壤敷设。 展开更多
关键词 三芯电缆 材料热阻系数 导体温度 归一化灵敏度 有限元仿真
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基于材料热阻的辐射空调末端换热性能分析
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作者 韩成 《建筑热能通风空调》 2020年第3期12-15,共4页
毛细管换热器表面敷设的装饰层材料对辐射顶板表面温度和热流密度有较大的影响,本文提出材料热阻的概念,通过模拟得出材料热阻值,再进行拟合得出装饰层导热系数和材料热阻的函数曲线图,通过实验验证模拟的准确性。结果表明基于材料热阻... 毛细管换热器表面敷设的装饰层材料对辐射顶板表面温度和热流密度有较大的影响,本文提出材料热阻的概念,通过模拟得出材料热阻值,再进行拟合得出装饰层导热系数和材料热阻的函数曲线图,通过实验验证模拟的准确性。结果表明基于材料热阻的工程预估具有较为精确的实际应用价值。 展开更多
关键词 材料热阻 换热性能 导热系数 辐射顶板 工程应用
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高压单芯电缆铝护套下热阻的动态特性与实验研究 被引量:21
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作者 刘刚 周凡 刘毅刚 《高电压技术》 EI CAS CSCD 北大核心 2013年第3期712-718,共7页
为了掌握电缆铝护套至导体热阻随温度变化的规律,提出了电缆铝护套至导体热阻的模型,通过高压单芯电缆阶跃电流温升实验,得到电缆各层在不同稳态下的温度分布,并根据热阻定义,推导电缆各层在不同温度下的热阻值及其随温度变化的规律。... 为了掌握电缆铝护套至导体热阻随温度变化的规律,提出了电缆铝护套至导体热阻的模型,通过高压单芯电缆阶跃电流温升实验,得到电缆各层在不同稳态下的温度分布,并根据热阻定义,推导电缆各层在不同温度下的热阻值及其随温度变化的规律。结果表明:电缆铝护套至导体热阻随温度的升高而降低,递减速率随温度的升高而变缓,并趋于稳定;单位长度电缆的绝缘层热阻和铝护套至导体热阻分别趋近于0.50 K.m/W和0.55K.m/W,其值比IEC 60287标准计算值分别小0.054 7K.m/W和0.077 1K.m/W;求得铝护套至导体热阻率为3.070K.m/W,比标准值小0.43K.m/W;气隙层热阻值为空气强制对流热阻值和接触热阻值并联之和,其值比标准值小1个数量级。 展开更多
关键词 高压单芯电缆 热阻模型 热阻 材料热阻 接触热阻 动态特性
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高功率半导体激光器过渡热沉封装技术研究
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作者 周小舒 黄庆 《科技资讯》 2024年第18期84-86,共3页
首先,通过有效改善激光器的热管理和稳定性能,包括热沉设计、封装材料选择、界面优化等,这些措施共同作用于激光器的热管理系统中,以确保激光器在高功率运行下仍能保持稳定和高效的性能。其次,通过热分析和模拟,优化过渡热沉与激光器芯... 首先,通过有效改善激光器的热管理和稳定性能,包括热沉设计、封装材料选择、界面优化等,这些措施共同作用于激光器的热管理系统中,以确保激光器在高功率运行下仍能保持稳定和高效的性能。其次,通过热分析和模拟,优化过渡热沉与激光器芯片之间的界面接触,降低接触热阻,提高热传导效率。最后,通过仿真计算和实验验证,评估技术的性能和优化效果。研究表明,这些技术对提高激光器的散热效果和长期稳定性具有重要意义,并推动激光器技术的发展。 展开更多
关键词 过渡热沉 高功率半导体激光器 焊料 材料热阻
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相变随机存储器材料与结构设计最新进展 被引量:5
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作者 刘波 宋志棠 封松林 《半导体技术》 CAS CSCD 北大核心 2008年第9期737-742,共6页
介绍了相变随机存储器(PCRAM)的研究现状,包括新型相变材料、热阻层材料和器件结构等。分析了GeSb和SiSb等相变材料具有组分简单、数据保持力好、优良的存储性能等特点,介绍了PCRAM这一新型半导体存储器的基本原理、特点以及国内外有关... 介绍了相变随机存储器(PCRAM)的研究现状,包括新型相变材料、热阻层材料和器件结构等。分析了GeSb和SiSb等相变材料具有组分简单、数据保持力好、优良的存储性能等特点,介绍了PCRAM这一新型半导体存储器的基本原理、特点以及国内外有关相变材料、过渡层材料和器件结构设计等方面的研究进展,最后提出了我国发展PCRAM的几点思考。 展开更多
关键词 相变随机存储器 相变材料 热阻材料
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固液热阻对无烟煤阴燃蔓延特性影响实验研究
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作者 黄万齐 唐一博 +2 位作者 郭倩 王俊峰 马冬娟 《燃烧科学与技术》 CAS CSCD 北大核心 2022年第5期591-598,共8页
煤炭阴燃是地下煤火灾治理的难点,治理过程中往往依赖于灌浆等方法,但其治理效果缺乏科学的评判依据.为了高效防治地下煤炭阴燃火灾,结合地下煤矿火灾治理规律,依托自制实验装置对比了原始条件与热阻干扰情况下无烟煤正向阴燃蔓延特性.... 煤炭阴燃是地下煤火灾治理的难点,治理过程中往往依赖于灌浆等方法,但其治理效果缺乏科学的评判依据.为了高效防治地下煤炭阴燃火灾,结合地下煤矿火灾治理规律,依托自制实验装置对比了原始条件与热阻干扰情况下无烟煤正向阴燃蔓延特性.在连续松散煤体间填充5 cm水、岩粉、金属网、凝胶作为实验热阻,分析填充实验热阻对阴燃峰值温度、阴燃峰值升温速率以及阴燃蔓延速率等煤炭阴燃参数的影响.结果表明:填充水后已燃区温度增加4.7~109.0℃,且能促进煤样阴燃传播,而填充岩粉、金属网、凝胶材料后已燃区温度降低了30.7~422.1℃,且阴燃难以维持传播,总体上热阻对传播的抑制效率排序为:凝胶>金属网>岩粉>水.运用熵值法定义权重及计算的阴燃蔓延危险性综合指数排序为:水>原煤>岩粉>金属网>凝胶.分析和结果可以为快速高效控制阴燃的大面积传播和科学设置火灾缓冲带提供科学依据. 展开更多
关键词 煤火 无烟煤 正向阴燃 热阻材料 蔓延速率 熵值法
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绿色建筑墙体的节能与保温 被引量:2
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作者 谭富微 陈纲伦 《武汉职业技术学院学报》 2005年第1期45-47,共3页
我国正处于经济建设的高速增长期,作为大量消耗能源与资源的建筑业要承担起其社会责任。文章对墙体设计中的节能措施及技术作了阐述,并展望了绿色节能建筑的未来和我们面临的挑战。
关键词 绿色建筑 节能墙体 墙体保温 透明热阻材料组合墙
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Application of thermal electrochemical equation to metal-hydride half-cell system 被引量:1
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作者 刘开宇 黄伯云 +3 位作者 张平民 贺跃辉 周科朝 苏耿 《Journal of Central South University of Technology》 EI 2006年第2期146-150,共5页
Application of thermal electrochemical equation to metal-hydride half-cell system was investigated, and the influence of state of charge on the thermal electrochemical performance of hydrogen storage materials was stu... Application of thermal electrochemical equation to metal-hydride half-cell system was investigated, and the influence of state of charge on the thermal electrochemical performance of hydrogen storage materials was studied. The results show that both the absolute value of the molar enthalpy change and the internal resistance of evolution hydrogen reaction are less than that of absorption hydrogen reaction at the same state of charge. The molar reaction enthalpy change of absorption and evolution of hydride electrode change contrarily with the enhancement of filling degree of hydrogen in hydride electrode. The relation curve of molar reaction enthslpy change to state of charge, both absorption and evolution hydrogen reaction, is close to a constant when the state of charge is 10%- 60%, and during state of charge below 10% or state of charge above 60%, the molar reaction enthalpy change varies sharply. Meanwhile, the internal resistance of electrode reaction has an ascending trend with the enhancement on filling degree of hydrogen in hydride electrode in both absorption and evolution hydrogen reaction. 展开更多
关键词 hydrogen storage material thermal electrochemical method state of charge APPLICATION change of enthalpy internal resistance
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缓解城市热岛效应沥青混合料性能试验分析 被引量:2
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作者 袁自能 《公路与汽运》 2016年第1期118-121,共4页
随着中国经济的高速发展,城市规模越来越大,城市热岛效应也越来越明显。热岛效应不仅吸收城市中的热辐射能量,产生大量氮氧化物,还会使城市空气质量下降。作为城市环境中单体建筑面积较大的城市道路,因自身的高吸热性,使热岛效应进一步... 随着中国经济的高速发展,城市规模越来越大,城市热岛效应也越来越明显。热岛效应不仅吸收城市中的热辐射能量,产生大量氮氧化物,还会使城市空气质量下降。作为城市环境中单体建筑面积较大的城市道路,因自身的高吸热性,使热岛效应进一步加剧。文中在总结国内外研究成果的基础上,提出用热阻集料替换天然粗、细集料,以减少路面内部热量传递,降低城市环境温度,进而减轻城市热岛效应;并对采用这种材料的道路的性能进行检测,结果表明其功能性及路用性能良好。 展开更多
关键词 公路 城市热岛效应 沥青混合料 吸热 热阻材料
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Microstructures and properties of Cu/Ag(Invar) composites fabricated by powder metallurgy
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作者 Xin ZHANG Dan WU +3 位作者 Lei YANG Chang-dong SHI Yu-cheng WU Wen-ming TANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第8期1759-1766,共8页
The Ag(Invar)composite powder prepared by ball milling was used to fabricate the Cu/Ag(Invar)composites.Microstructures and properties of the composites were studied after sintering and thermo-mechanical treatment.The... The Ag(Invar)composite powder prepared by ball milling was used to fabricate the Cu/Ag(Invar)composites.Microstructures and properties of the composites were studied after sintering and thermo-mechanical treatment.The results indicatethat during ball milling,micro-forging weld and work-hardening fracture result in that the average particle size of the Ag(Invar)powder increases rapidly at first,and then decreases sharply,finally tends to be constant.Compared with the Cu/Invar ones,thesinterability of the composites is greatly improved,resulting in that the pores in them are smaller in amount and size.After thethermo-mechanical treatment,the Cu/Ag(Invar)composites are nearly fully dense with the optimum phase composition and elementdistribution.More importantly,Cu and the Invar alloy in the composites distribute continuously in a three-dimensional(3D)networkstructure.Cu/Invar interface diffusion is effectively inhibited by the Ag barrier layer,leading to a great improvement of themechanical and thermal properties of the Cu/Ag(Invar)composites. 展开更多
关键词 Cu/Invar composite Ag barrier layer SINTERING thermo-mechanical treatment 3D network structure mechanical properties thermal properties
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Modification of HDPE filling with pelagic clay
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作者 ZHAO Liang ZHANG Peiping +2 位作者 ZHANG Dongli LIU Xuesong LU Huahua 《Global Geology》 2010年第2期108-112,共5页
In order to improve the properties of HDPE, the authors used the method of suspended diffusion for purification the pelagic clay, used silane coupling agent to increase its organic activation, and prepared the composi... In order to improve the properties of HDPE, the authors used the method of suspended diffusion for purification the pelagic clay, used silane coupling agent to increase its organic activation, and prepared the composites of organic pelagic clay/HDPE by inching them in different conditions. The affections of process conditions and quantity of pelagic clay to the properties of composites were analyzed by testing their mechanical properties, thermo stability and barrier properties. According to test the structure of composites, it is indicated that pelagic clay has good compatibility with HDPE. The result shows that the pelagic clay can improve mechanical properties, thermo stability and barrier properties of HDPE properties effectively. 展开更多
关键词 pelagic clay filling modification HDPE properties and structure
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Flame Retardants Nanocomposites-Synergistic Effect of Combination Conventional Retardants with Nanofillers of the Flammability of Thermoset Resins
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作者 Ewa Kicko-Walczak Grazyna Rymarz 《Journal of Mechanics Engineering and Automation》 2015年第9期510-518,共9页
The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of t... The consumption ofthermoset resins as building polymers is approximately over one million tone word wide. The thermoset resins are proven construction materials for the technical and highly demanding applications of the transportation, electrical and building part industry. Heat stability, high thermal, low shrinkage, excellent mechanical properties are typical for their type of polymers. Above applications in addition to the mechanical properties also require good flame retardants of the materials. Undertaken activities refer to official draft, laws and legal recommendations in UE states. This paper presents positive effect of reduced flammability of thermoset resins (unsaturated polyester and epoxy resins) thanks to the use of nanocomposites containing multi-ingredient halogen-flee flame retardants which combine conventional phosphorus/nitrogen modifiers interacting with nanofillers (oMMT (organomodified montmorillonite), EG (expandable graphite), graphene, GO (graphene oxide), nSi (nanosilica)). 展开更多
关键词 FR (fire retardants) halogen-free FR additives NANOFILLERS nanocomposites flammability of thermoset resins test methods.
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Flame retarded polymer nanocomposites: Development,trend and future perspective 被引量:6
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作者 MA HaiYun SONG PingAn FANG ZhengPing 《Science China Chemistry》 SCIE EI CAS 2011年第2期302-313,共12页
Polymer nanocomposites are a new class of flame retarded materials which have attracted much attention and considered as a revolutionary new flame retardant approach.A very small amount of nano flame retardants (norma... Polymer nanocomposites are a new class of flame retarded materials which have attracted much attention and considered as a revolutionary new flame retardant approach.A very small amount of nano flame retardants (normally < 5 wt%) can significantly reduce the heat release rate (HRR) and smoke emission (SEA) during the combustion of polymer materials.Moreover,the addition of nano flame retardants can also improve the mechanical properties of polymer materials compared with the deterioration of traditional flame retardants.This paper reviews the recent development in the flame retardant field of polymer nanocomposites and also introduces the related research in our lab.The challenges and problems are discussed and the future development of flame retarded polymer nanocomposites is prospected. 展开更多
关键词 NANOCOMPOSITE layered silicate carbon nanotubes FULLERENE flame retardancy
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Ultra-low charge transfer resistance carbons by onepot hydrothermal method for glucose sensing
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作者 胡博韬 刘仁材 +3 位作者 陈靖容 赵湛 张淑真 康沛伦 《Science China Materials》 SCIE EI CSCD 2017年第12期1234-1244,共11页
Hydrothermal carbon (HTC) is typically well- dispersed, but it remains a great challenge for HTC to become conductive. Co-doping with heteroatoms has been confirmed to be an effective strategy to significantly promo... Hydrothermal carbon (HTC) is typically well- dispersed, but it remains a great challenge for HTC to become conductive. Co-doping with heteroatoms has been confirmed to be an effective strategy to significantly promote the electrical conductivity of carbon. Moreover, there is no simple and green method to construct sensitive HTC based electro- chemical biosensors until now. In this paper, N and S dual-doped carbon (NS-C) with ultra-low charge transfer resistance is easily synthesized from L-cysteine and glucose in a hydrothermal reaction system. The morphology, structural prop- erties and electrochemical properties of the as-prepared NS-C are analyzed. In comparison with the undoped hydrothermal (UC) modified glassy carbon electrode (GCE), the charge transfer resistance of UC (476 Ω) is ten times the value of NS- C (46 Ω). The developed biosensor shows a better performance to detect glucose in a wide concentration range (50-2500 μmol L^-1) with the detection limit of 1.77 μmol L^-1 (S/N-3) and a high sensitivity (0.0554 μA cm^-2μmol^-1 L). The apparent Michaelis-Menten constant value of GCE/NS-C/GOx/nafion modified electrode is 0.769 mmol L^-1, indicating a high affinity of glucose oxidase to glucose. These results demonstrate that the hydrothermal method is an effective way for prepar- ing high electrical conductivity carbon with excellent performances in biosensor application. 展开更多
关键词 hydrothermal method glucose biosensor charge transfer resistance heteroatom doped carbon electrochemical behavior
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