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  • 1990-1994  (2)
  • 1991  (2)
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  • 1990-1994  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    An electrograph for measurement of macroscopic electric fields in prominences and flares (1991)
    Springer
    Solar physics 135 (1991), S. 179-191 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe an ‘electrograph’ instrument designed for measurement of macroscopic electric fields in solar plasmas, using the polarization dependence of line width in Stark-broadened hydrogen Paschen emission lines. Observations of quiescent prominences and limb chromosphere with our electrograph at the NSO/Sac Peak Evans Coronal Facility provide upper limits of 5–10 V cm−1 for transverse macroscopic electric fields in these structures, averaged over an area of about 5 × 7 arc sec. Random thermal motions of hydrogen ions across magnetic field lines generate a quasi-static electric field, which should be distinguishable from pressure broadening in the intensely magnetized chromosphere over a sunspot, given an electrograph sensitivity a factor 2–3 better than that achieved here. Future electrograph measurements of limb flares, post-flare loops and eruptive prominences, even at 5 V cm−1 sensitivity, could provide a useful new test of reconnection and discharge effects in such dynamic structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146705
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Positive and negative methanol cluster ions using a direct fast atom bombardment technique (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 26 (1991), S. 892-898 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive and negative cluster ions in methanol have been examined using a direct fast atom bombardment (FAB) probe technique. Positive ion (CH3OH)IIH + clusters with n = 1-28 have been observed and their clusters are the dominant ions in the low-mass region. Cluster-ion reaction products (CH3OH)II(H2O)H+ and (CH3OH)II(CH3OCH3)H+ are observed for a wide range of n and the abundances of these ions decrease with increasing n. The negative ion (CH3OH)II(CH3O)- clusters are also readily observed with n = 0-24 and these form the most-abundant negative ion series at low n. The (CH3OH)II(CH2O)-, (CH3OH)II(HIIO)(CH2O)- and (CH3OH)II(H2OXCH3O)- cluster ions are formed and the abundances of these ions approach those of the (CH3OH)II(CH3O)- ion series at high n. Cluster-ion structures and energetics have been examined using semi-empirical molecular orbital methods.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210261016
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    Paper (German National Licenses)
    Fulltext
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