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  • 1
    Electronic Resource
    Electronic Resource
    Anharmonic thermal vibrations in Mg2Si (1970)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 26 (1970), S. 292-293 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The recent X-ray diffraction data front Mg2Si, obtained by Panke & Wölfel (Z. Kristallogr. (1969), 129, 9) show systematic differences in the structure factors from those predicted by a model which assumes harmonic thermal vibration of the atoms. These differences indicate an anharmonic component in the thermal vibration of the magnesium atoms, consistent with their tetrahedral site symmetry. An analysis of these data has therefore been carried out in terms of a model which includes anharmonic thermal vibration and a least-squares refinement gave a value of the anharmonicity parameter (βMg = − 2.39 × 10−12 erg.Å−3) which is similar in magnitude to those found for other systems with the fluorite structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739470000682
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of multiple diffraction on the determination of electron density distributions (1968)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 1 (1968), S. 255-257 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Single-crystal intensity measurements on Mg2Si were checked for simultaneous diffraction by rotating the crystal around the scattering vector. The integrated intensity was measured as a function of the azimuthal angle. For some weak reflexions Umweganregung peaks were found exactly in the position of the crystal that one would normally use without consideration of multiple diffraction. If ignored, these effects lead to significant errors in the electron density distribution calculated from the experimental structure factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889868005443
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Polymerization of methyl methacrylate up to high degrees of conversion: Experimental investigation of the diffusion-controlled polymerization (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2243-2253 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetic model given by Marten and Hamielec that describes the bulk polymerization of methyl methacrylate (MMA) and accounts for diffusion-controlled termination and propagation was modified to include termination by combination and reaction diffusion and was then tested using isothermal conversion/time and molecular weight data obtained dilatometrically at various temperatures and with three different initiators. For each series of measurements two adjustable parameters were fitted to the conversion/time data. Excellent fits were obtained and the adjustable parameters were found to be the same for all concentration levels of the three initiators and to vary in a simple manner with temperature. The predicted molecular weight averages and molecular weight distributions were in satisfactory agreement with those found experimentally considering the difficulty of measuring high molecular weight PMMA by GPC. This model thus satisfies the specifications for a polymer reactor model that can be used to optimize commercial production systems.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220924
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  • 4
    Electronic Resource
    Electronic Resource
    Strukturuntersuchungen an Polymethylmethacrylat und Methylmethacrylat-Copolymeren in Lösung (1972)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 84 (1972), S. 365-365 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19720840840
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  • 5
    Electronic Resource
    Electronic Resource
    Bestimmung des freien volumens von polymethylmethacrylat aus dichtemessungen (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 167 (1973), S. 351-352 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021670128
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    Paper (German National Licenses)
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