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  • 1980-1984  (3)
  • 1970-1974  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 84 (1980), S. 198-202 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 9 (1970), S. 525-534 
    ISSN: 1435-1528
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zusammenfassung In diesem Beitrag wird auf einige Aspekte rheologischer Modelle, die partielle Differentialquotienten enthalten, eingegangen. Nach einem kurzen historischen Überblick über die Anwendungen dieser Differentialquotienten in der Rheologie wird eine mathematische Formulierung gegeben. Auch wird gezeigt, wie diese Differentialquotienten in rheologische Modelle eingeführt werden können; das dynamische Verhalten eines einfachen Modells wird mit Hilfe verschiedener Experimente, wie sie oft an viskoelastischen Stoffen durchgeführt werden, berechnet. Das Modell wird anhand der Ergebnisse einiger Messungen an Nylon 6- und PETP-Fasern geprüft; dies veranlaßte die Einführung eines elastischen Terms. Schließlich wird die Beziehung zwischen partielle Differentialquotienten enthaltenden Modellen und den wichtigsten Gleichungen der Theorie der linearen Viskoelastizität in großen Zügen angegeben.
    Notes: Summary In this contribution some aspects of rheological models containing fractional derivatives are shown. After a short historical review of the application of fractional derivatives in rheology, a mathematical formulation of these derivatives is given. The possibility of using fractional derivatives in the construction of rheological models is demonstrated. The behaviour of a simple fractional derivative model is calculated in a number of experiments, often performed on fibres. The model is checked against the results of some measurements on nylon 6 and PETP fibres, which leads to the addition of an elastic term. Finally, in broad outline, the relation between fractional derivative models and the principal expressions of the theory of linear viscoelasticity is indicated.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. Reactions of dicoboalt hexacarbonyl complexes of conjugated enynes with cationoid reagents of the type acyl-, alkyl-, nitronium, and arylsulfene-tetrafluoroborates leads to formation of cationoid intermediates which are stable in solution. These cationoid intermediates may then react with nucleophiles of the water or methanol type with formation of covalent adducts. 2. The observed two-step AdE-reaction is a suitable route for synthetic use of enynes, which is shown for the case of the syntheses of a number of monoterpenoids.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 16 (1984), S. 1481-1494 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rates and thermodynamic data have been obtained for the reversible self-termination reaction: \documentclass{article}\pagestyle{empty}\begin{document}$${\rm R}^ \cdot + {\rm R}^ \cdot \mathop{\buildrel\longleftarrow\over\longrightarrow}^{2k1}_{2k_{-1}}D $$\end{document} Involving aromatic 2-(4′dimethylaminophenyl)indandione-1,3-yl (I), 2-(4′diphenylaminophenyl)indandione-1,3-yl (II), and 2,6 di-tert-butyl-4-(β-phthalylvinyl)-phenoxyl (III) radicals in different solvents. The type of solvent does not tangibly affect the 2k1 of Radical(I), obviously due to a compensation effect. The log(2k1) versus solvent parameter ET(30) curves for the recombination of radicals (II) and (III) have been found to be V shaped, the minimum corresponding to chloroform. The intensive solvation of Radical (II) by chloroform converts the initially diffusion-controlled recombination of the radical into an activated reaction. The log (2k-1) of the dimer of Radical (I) has been found to be a linear function of the Kirkwood parameter (ε - 1)/(2ε + 1), the dissociation rate increasing with the dielectic constant of the solvent. The investigation revealed an isokinetic relationship for the decay of the dimer of Radical (I), an isokinetic temperature β = 408 K and isoequilibrium relationship for the reversible recombination of Radical (I) with β° = 651 K. For Radical (I) dimer decay In(2k-1) = const + 0.8 In K, where K is the equilibrium constant of this reversible reaction. The transition state of Radical (I) dimer dissociation reaction looks more like a pair of radicals than the initial dimer. The role of specific solvation in radical self-termination reactions is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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