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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 50 (1997), S. 547-558 
    ISSN: 1572-8943
    Keywords: indium ; melting ; temperature calibration ; TMDSC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The melting and crystallization of a sharply melting standard has been explored for the calibration of temperature-modulated differential scanning calorimetry, TMDSC. Modulated temperature and heat flow have been followed during melting and crystallization of indium. It is observed that indium does not supercool as long as crystal nuclei remain in the sample when analyzing quasi-isothermally with a small modulation amplitude. For standard differential scanning calorimetry, DSC, the melting and crystallization temperatures of indium are sufficiently different not to permit its use for calibration on cooling, unless special analysis modes are applied. For TMDSC with an underlying heating rate of 0.2 K min−1 and a modulation amplitude of 0.5–1.5 K at periods of 30–90 s, the extrapolated onsets of melting and freezing were within 0.1 K of the known melting temperature of indium. Further work is needed to separate the effects originating from loss of steady state between sample and sensor on the one hand and from supercooling on the other.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 54 (1998), S. 545-563 
    ISSN: 1572-8943
    Keywords: frequency domain ; heat-flux calorimeter ; indium ; integral analysis ; melting transition ; pseudo-isothermal analysis ; quasi-isothermal measurement ; reversible melting ; saw-tooth modulation ; sinusoidal modulation ; temperature-modulated calorimetry ; time-domain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Indium was analyzed with both, standard differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) using sinusoidal and saw-tooth modulation. Instrument and sample effects were separated during nucleated, reversible melting and crystallization transitions, and irreversible crystallization with supercooling. The changes in heat flow, time, and sample and reference temperatures were correlated as functions of heating rate, mass, and modulation parameters. The transitions involve three regions of steady state (an initial and a final region before and after melting/crystallization, a region while melting/crystallization is in progress) and one region of approach to steady state (melting peak to final steady state region). Analyses in the time domain show promise when instrument lags, known from DSC, are used for correction of TMDSC. A new method of integral analysis is introduced for quantitative analysis even when irreversible processes occur in addition to reversible transitions. The information was derived from heat-flux calorimeters with control at the heater block or at the reference temperature sensor.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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