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DSC是差示扫描量热计的简称。它是60年代在国际上出现的一项量热新技术。由于其功能可以和光谱仪媲美,有时也称之为热谱仪。DSC的量热原理与传统的量热学原理迥然不同。首先阐明这一原理的是Watson等人。根据Watson原理首先研制DSC的是美国Perkin-Elmer公司。DSC在自然科学和技术科学各领域中具有广泛的应用,在形形色色的工业部门中也具有种种重要用途。DSC在化学领域中的应用,主要有三个方面:其一为物质热力学性质的 相似文献
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以聚乙二醇(PEG)为软段、六亚甲基二异氰酸酯-1,4-丁二醇-二羟甲基丙酸(HDI-BDO-DMPA)为硬段,制备了一系列水性聚氨酯相变储能材料(WPUPCM)。在相变过程中,由于软段PEG由聚合前的固-液相变转化为聚合后的固-固相变,因此,所制备的WPUPCM表现出固-固相变特性。为了研究其固态相变行为的本质和形成机理,揭示该类聚合物的能量贮存和转换机理,应用偏光显微镜、扫描电镜、原子力显微镜、X射线衍射仪分析研究了PEG、WPUPCM在相变过程中的晶体结构变化特征,讨论了WPUPCM固-固相转变的机理。 相似文献
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电能和热能作为生活生产中最大的供应端和消耗端,二者间的转换、存储与利用在能源体系里占据了重要的一环。因此,研发高效率的电热转换-存储功能材料,在能源、环境和气候危机频现的今天,具有重要的意义。相变材料的储热密度高、相变时吸放热而温度不变,在热能存储中具备独特的优势。然而大多数相变材料的本征低电导率与当下储能系统的功率要求不匹配,通过与导电材料结合得到电热转化的相变复合材料可以有效地改变这种情况。本文对电热转换相变材料最新研究进展进行了综述,从电热转换相变材料的功能机制、影响因素和应用三个方面,对添加导电填料、负载导电骨架或导电高分子聚合的复合相变材料进行了综述与比较。最终对此领域未来的研究方向和重点进行了展望。 相似文献
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相变蓄热材料研究进展 总被引:2,自引:0,他引:2
相变蓄热材料(恒温潜热热能储存材料)是目前最热门的功能材料之一。它在发生相变时储存、放出的热量能够帮助所在系统进行能量的储存,同时可以一定程度上缓解双方在时间、强度及地点上的不匹配程度。相变蓄热材料优点突出,其中包括在使用过程中自身温度变化较小、有很好的稳定性、储热能力较强等。此类材料对环境友好,响应了国家近年来节能环保的政策,同时也可以极大地优化所在系统的运行效率。本文综述了近年来几类相变蓄热材料的种类、特点及国内外学者应对于不同缺陷做出的改进及其应用于行业的研究现状,并对未来的发展进行了探讨与展望。 相似文献
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我们利用Born-Mayer-Huggins相互作用势函数对(KF)N(N=108,256,500和864)团簇进行了分子动力学(MD)模拟。为了避免周期性边界条件对相变、成核和重结晶的干扰作用,对体系采用了自由边界。基于MD模拟结果,对团簇的熔化温度、熔化焓、扩散系数、成核速率、固液界面自由能、临界核大小等进行了计算和讨论。在对(KF)864双晶团簇的热退火模拟中,观察到了固态的重结晶和晶粒的生长。经典的成核理论成功地解释了(KF)864双晶团簇的重结晶MD模拟结果。 相似文献
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高分子凝胶的体积相变 总被引:4,自引:0,他引:4
本文概要地介绍了高分子凝胶体积相变的基础理论,较系统地综述了近10年来利用温度、pH值、光、电、生化反应等控制体积相变研究的进展,对有关的应用也作了简单的介绍. 相似文献
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J. M. Hey P. M. Mehl D. R. MacFarlane 《Journal of Thermal Analysis and Calorimetry》1997,49(2):991-998
A simultaneous differential scanning calorimeter (DSC)-optical video microscope instrument has been developed. The instrument development included slight modifications to the sample head of a Perkin-Elmer DSC-7, along with the use of a CCD camera and magnifying lenses. The instrument permitted simultaneous following of optical and thermal events during isothermal and non-isothermal DSC experiments. The DSC curves were almost identical to those given by a standard DSC-7. The operational temperature range of the instrument is between –160 to 600°C. The capabilities of the DSC-video microscope are illustrated by examples of ice crystallization data in aqueous solutions of glycerol and dimethyl sulphoxide.Naval Medical Research and Development Command, Work Unit No. 61153 N. MRO 4120.001-1462 NM R&D. The opinions and assertions contained herein are the private ones of the writers and are not to be construed as official nor as representing those of Defense or of the Navy. 相似文献
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Summary Crystallization and melting of microsize droplets of D2O and H2O+D2O mixtures dispersed within an emulsifying medium have been studied by means of a Perkin-Elmer DSC 2 differential scanning calorimeter.
With 7 figures and 1 table 相似文献
Zusammenfassung In der vorliegenden Arbeit wurde das Gefrieren und Schmelzen mikroskopischer Tropfen von D2O oder (H2O+D2O) Mischungen in Emulsionen mit Hilfe eines Perkin-Elmer DSC 2 Kalorimeters studiert.
With 7 figures and 1 table 相似文献
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This paper presents a new method for the calculation of the purity of organic, non-polymeric samples using the recorder trace from a Differential Scanning Calorimeter (DSC), Perkin-Elmer Corp. The entire DSC recorder trace is employed rather than only the initial portion of the curve. The previous trial and error choice of energy lost by the DSC trace has been replaced by a definite numerical value. Meaningful purity values have been obtained from a single DSC trace on samples of from 95 to 99.9% purity. This new method has been demonstrated to provide more accurate and less ambiguous results than the manufacturer's procedure. 相似文献
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The glass transition of an irradiated, ultra-high molecular weight, linear polyethylene was investigated by means of the Perkin-Elmer DSC-2 differential scanning calorimeter. The experimental specific heat data were compared with those of the nonirradiated sample, obtained by DSC and adiabatic calorimetry. 相似文献
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R. Schubring 《Journal of Thermal Analysis and Calorimetry》2005,82(1):229-237
Present research concentrated on high pressure assisted thawing of fish fillets from commercially important fish species such
as ocean perch, saithe and herring. DSC (Perkin-Elmer DSC 7) has been used to follow the pressure-induced changes of proteins.
Results of pressure assisted thawing are compared to those of conventional thawing in water at 10°C and ambient pressure.
The results obtained clearly demonstrate that changes in DSC curves become pronounced with advancing high pressure and are
dependent on the species of fish. 相似文献
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