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  • 1
    ISSN: 1573-5117
    Keywords: atmospheric aerosols ; lead ; time serie ; solubility ; seawater ; eastern channel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to describe the seasonal variability of the atmospheric lead concentrations above the Eastern Channel, aerosols samples have been collected by bulk filtration at the Cape Gris-Nez (Dover Strait) during one year. A statistical analysis of the obtained time-series from lead concentrations and rain amounts illustrates the geochemical implications of a scavenging process: when precipitations become lower than the average rain events, the lead concentrations become higher than the mean values and reciprocally. On a global scale, the lead concentrations over the Eastern Channel and the Southern Bight of the North Sea have decreased by about one order of magnitude since fifteen years. Lead concentrations have been compared to the origin of the collected air masses. The use of the back-trajectories permits us to classify the origins of the air masses among five geographical sectors relevant to the position of our sampling site: Atlantic Ocean and English Channel; North Sea; British Islands; Southern and Western Europe; Scandinavia and Central Europe. Continental sectors show greater lead concentrations than marine and semi-continental sectors, by a factor of about 3 to 7. These results are in a good agreement with the assumption according to which the atmospheric lead is mainly associated with emissions from heavy industrialised and urbanised areas, especially from automotive origin. Under our experimental conditions, the solubility in a coastal seawater for 'continental' lead is different from the one of 'maritime' lead. These dissolution experiments are developed in order to ultimately answer to the questions 'how does the dry fall-out scatter into the upper layer of the seawater mass, regarding as a chemical system?' and more particularly 'what is the part of the heavy metals transported via the atmosphere which is rapidly transferred into the dissolved phase, i.e. under a labile form potentially available for the interfacial organisms?'
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 1137-1143 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polychlorophosphazenes 2 can easily be obtained by thermal condensation of dichlorophosphinoyliminotrichlorophosphorane (1) under atmospheric pressure at 240-290°C, pure POCl3 being eliminated. The different stages of the reaction were studied by chemical analysis, 31P NMR, IR spectroscopy, and thin layer chromatography. The procedure enables one to obtain polymers of low and high molecular weights. The samples do not contain any cyclic or reticular polymers. Species of low molecular weights can be separated from those with high molecular weights by treatment with heptane. The total yield of phosphorus is 100% with regard to the starting material. Substitution products (Cl by OCH2CF3) are obtained which are identical with those obtained with the polychlorophosphazenes prepared via classical methods.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 511 (1984), S. 212-218 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktion zwischen Bis(dichlorophosphoryl)imid und HexamethyldisilazanBei der Reaktion zwischen Bis(dichlorophosphoryl)imid und Hexamethyldisilazan - mit oder ohne Lösungsmittel - wurden zwei Phasen erhalten.Die feste Phase ist das Ammoniumsalz des Bis(dichlorophosphoryl)imids, das auch wie manche Metallsalze desselben Typus durch die allgemeine Reaktion \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Cl}_2 {\rm - P(O) - N = PCl}_{\rm 3} + {\rm AO}_{\rm n} ^{\rm - } {\rm M}^{\rm + } \to {\rm MN(P(O)Cl}_{\rm 2})_2 + {\rm AO}_{{\rm n - 1}} {\rm Cl} $$\end{document} erhalten werden kann. Dieses Salz wird durch IR, 31P-, 1H- und 14N-NMR sowie die Hydrolyse charakterisiert.Die Zusammensetzung der flüssigen Phase ändert sich je nach den experimentellen Bedingungen. Die ersten Hauptprodukte sind offenbar Cl2(O)P—N=P(OSiMe3)Cl2 und Cl2(OSiMe3)P=N—PCl(OH)NSiMe3. Diese Verbindungen kondensieren dann weiter zu Hochpolymeren.
    Notes: By reaction between bis(dichlorophosphoryl)imide and hexamethyldisilazane - with or without solvent - the authors obtain two phases.The solid phase is the ammonium salt of the bis(dichlorophosphoryl)imide which can be obtained, like many other metallic salts of this type, by the general reaction: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Cl}_2 {\rm P(O) - N = PCl}_{\rm 3} + {\rm AO}_{\rm n} ^{\rm - } {\rm M}^{\rm + } \to {\rm MN(P(O)Cl}_{\rm 2})_2 + {\rm AO}_{{\rm n - 1}} {\rm Cl} $$\end{document}.The salt is characterized by its I.R., and 31P, 1H, and 14N N.M.R. spectra and by its hydrolysis reaction.The composition of the liquid phase changes according the experimental conditions. It seems that at first the main components are Cl2(O)P—N=P(OSiMe3)Cl2 and Cl2(Me3SiO)P=N—PCl(OH)NSiMe3. These compounds condense further to high polymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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