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  • Chemistry  (1)
  • 1975-1979  (3)
  • 1
    Publication Date: 2011-08-17
    Description: The reported results are mainly based on data obtained during the first part of the Helios-1 mission. The sun was very quiet during the considered period. The data are, therefore, representative for comparatively stationary conditions in the solar corona. Data obtained concerning the protons were evaluated by means of a special computer routine. The significance of the data is discussed, taking into account the status of the corona and the interplanetary plasma during the considered part of the Helios-1 mission, fast stream structures in the region between 0.3 and 1 AU, radial gradients of fast and slow solar wind, and the separation of proton double streams and alpha-particles. Attention is also given to the 'strahl' in the electron distribution, differences between fast streams and slow plasma on the basis of the observed electron distributions, and radial gradients in the case of solar wind electron parameters.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysics - Zeitschrift fuer Geophysik; 42; 6, 19; 1977
    Format: text
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  • 2
    Publication Date: 2011-08-17
    Description: Observational evidence favoring the local regulation of solar-wind heat flux at 1 AU is reviewed, and four months of IMP 6 plasma and magnetic-field data are merged and analyzed in order to investigate what might be regulating the heat flux. A statistical analysis of the data shows that the solar-wind Alfven speed is probably regulating the heat flux locally at 1 AU and that the Alfven speed, the velocity difference between the peak of low-energy electrons and the bulk plasma velocity, and the solar-wind velocity component projected along the local spiral angle are statistically well correlated for Alfven speeds not exceeding about 70 km/s. A time-series analysis of the data indicates that only the Alfven speed and the velocity difference between the peak of low-energy electrons and the bulk plasma velocity are well correlated both qualitatively and quantitatively on a microscopic time scale. It is strongly suggested that, at times, the solar-wind heat flux is locally regulated by the magnitude of the Alfven speed at 1 AU. Uncertainties in the results are discussed.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Oct. 1
    Format: text
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  • 3
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compounds of the 3,4-dihydro-ionone series as models for the photochemistry of γ, δ- and δ,∊- unsaturated ketones and aldehydes.The photochemistry of γ, δ- and δ,∊-unsaturated carbonyl compounds of the dihydro-ionone series has been studied, with special attention to the investigation of oxetane formation versus hydrogen abstraction.UV.-irradiation of the dihydro-β-ionone compounds with structure A (1, 7, 14, 18, 24, 29) led to isomeric ethers with structures B (2, 8, 15, 19, 25, 30), C (3, 9, 16, 20, 26, 31) and D (4, 21, 27), isomeric bicyclic alcohols with structure E (5, 10, 17, 22, 28), and photoreduction products with structure F (6, 11, 12, 13). Photolysis of dihydro-γ-ionone (32) gave a complex mixture containing fragmentation product 35, hydrocarbon 36, β-ambrinol (34), oxetane 33, as well as dihydro-β-ionone (1) and three of its photoproducts (2, 3, 5). The dihydro-α-ionone compounds 37 and 40 gave mixtures of fragmentation products and the oxetanes 38 and 41. Irradiation of the side-chain homologues 42 and 45 yielded 43, which photo-cyclizes to 44. In contrast, 3, 4-dihydro-3′,4′-dehydro-β-ionone (46) gave merely the isomeric open-chain triene-ketone 47.The structures assigned to the ethers 2, 3, 33, 38 and to the alcohols 5, 10, 13 could be confirmed by chemical reactions and mutual interconversions. The structure of the ether 21 had to be established by X-ray analysis, details of which are described.A novel intramolecular hydrogen transfer is involved in formation of ethers B. The photocyclization A → D probably proceeds by addition of the carbonyl-C atom to the double bond (A → h), followed by methyl (1 → 2)-shift (h → i). Process A → h may also be involved in formation of compounds of type C and E.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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