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  • Chemistry  (2)
  • Best. von Blei in Benzin, Erdölprodukten  (1)
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 26 (1988), S. 329-329 
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1618-2650
    Keywords: Best. von Blei in Benzin, Erdölprodukten ; Röntgenfluorescenz-Spektrometrie ; Streustrahlmethode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Am Beispiel der Bleibestimmung in Ottokraftstoffen wird gezeigt, daß es möglich ist, die Compton-Streustrahlung einer Röhrenlinie für die Elementbestimmung mittels Röntgenfluorescenzspektrometrie als internen Standard zu benutzen. Anstelle der Compton-Streuung kann ggf. auch die gestreute Röhrenlinie selbst verwendet werden. Die Beziehung zur Konzentration des zu bestimmenden Elementes wird durch eine Vergleichsprobe mit bekannter Elementkonzentration hergestellt. Die Ergebnisse von Bleibestimmungen in Ottokraftstoffen, die nach diesem Verfahren erhalten wurden, stimmen mit den nach anderen Methoden erhaltenen Ergebnissen gut überein, sie liegen weit innerhalb der Vergleichbarkeit nach DIN 51769, Teil 1. Das beschriebene Verfahren ergibt gegenüber dem Verfahren mittels Zumischung eines internen Bezugselementes zur Probe eine Verringerung des Arbeitsaufwandes, eine Erniedrigung der unteren Bestimmbarkeitsgrenze und ggf. eine Vermeidung von Komplikationen durch Interelementeffekte.
    Notes: Summary Taking the determination of the lead content in gasoline as an example, it is shown that the Compton scattering of an X-ray tube emission line may be used as internal standard for determining elements by means of X-ray fluorescence spectroscopy. Also, the scattered tube line itself may be used instead of the Compton scattering. The relationship with the concentration of the element to be determined is established by comparison with a reference sample of known element concentration as an external standard. The results of the determination of lead in gasoline obtained by this method correlate well with those obtained by other methods and are well within the reproducibility limits specified by DIN 51769, Part 1. The method described brings about a reduction in work as compared with the method requiring the addition of an internal reference element to the sample, it brings down the bottom traceability limit and may eliminate complications caused by interelemental effects.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 1819-1827 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The influence of the chemical structure, composition, and physical properties of polymers [polyacrylates and -methacrylates, poly(vinyl acetate), polystyrene, and polybutadiene] and plasticized polymers [poly(methyl methacrylate) and polystyrene] on the Stokes shift of fluorescent dyes has been investigated. The results indicate that the structure and overall mobility of the polymer matrix as well as the nature of the dopant all together influence the separation of the absorption and emission band of a given fluorescent dye. In general, polar and highly flexible polymers favor the band separation. The effect of both polar and apolar dopants seems to be primarily a plasticization in case of polar polymers, whereas for apolar polymers the plasticizer effect can be neglected and the increased Stokes shift upon addition of polar dopants has to be attributed to particular dopant/dye interactions. These findings open some new routes to improve the efficiency of solar collectors based on fluorescent dyes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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