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  • 2000-2004
  • 1985-1989  (5)
  • 1975-1979
  • 1989  (5)
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  • 2000-2004
  • 1985-1989  (5)
  • 1975-1979
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  • 1
    Electronic Resource
    Electronic Resource
    Spectroscopic observations of the early-type contact binary AW Lacertae (1989)
    Springer
    Space science reviews 50 (1989), S. 354-354 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spectroscopic observations were performed of the early-type contact binary AW Lac with an image-intensified coude spectrograph of 1.9-m telescope at the Okayama Astrophysical Observatory. A total of twenty-two spectra covering blue region with a dispersion of 16 Amm-1 have been secured on Kodak IIa-O baked plates. In every spectra sharp interstellar CaII H,K lines are clearly seen. The spectral type of AW Lac has been estimated as early B, which substantially confirms the one adopted in the photometric analysis by Jiang et al. (1983) and is diffrent from A0 listed in General Catalogue of Variable Stars (Kholopov et al. 1985). Contrary to the suggestion by the photometric solution of Jiang et al., no definite secondary lines could be separated, though some indications of light contamination due to the secondary component are surely observed. This would imply that the light ratio of the components should be somewhat smaller than that derived by photometric analysis. No emission features appeared either. The measurement of radial velocities of the primary component for the orbital elements was made for twenty spectra by a conventional method. It was difficult to measure the radial velocities because the lines are quite broadened and deformed. Hence the measured values for the radial velocities should be regarded as rather preliminary. The derived spectroscopic elements, combined with the photometric data, give the absolute dimensions of the system for each assumed mass ratio q. For q = 1, being the adopted photometric solution by Jiang et al., we obtain too small value for the primary's mass, comparing with its spectral type. For the mass ratio as small as q = 0.6, we can obtain a reasonable value for the mass of the primary. However, in order to get more definite conclusion the cross-correlation method would be more appropriate for the spectroscopic analysis of this system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215959
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The gravity-darkening of the main-sequence components of spectral types A, F and G in detached close binary systems (1989)
    Springer
    Space science reviews 50 (1989), S. 353-353 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract From analysis of the photometric ellipticity effect in seven well-understood detached close binary systems, empirical values of the exponent α of gravity-darkening have been practically deduced for eleven main-sequence components of spectral types A, F and G which should cover the range of structural change (from radiative to convective) in stellar atmospheres. The result indicate that values of the exponent diminish gradually with decreasing effective temperatures from α ∼ 1.0 for radiative atmospheres with T 〉 8500 K to α = 0.2 ∼ 0.3 for convective atmospheres with T 〈 6500 K, in spite of some uncertainty in the reflection correction process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215958
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Conformational studies on L-serine phosphate and hydrated L-serine phosphate using ab initio SCF calculations (1989)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 35 (1989), S. 395-407 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio MO-LCAO-SCF calculations using an STO-3G basis set were performed to find the most stable conformations of L-serine phosphate and hydrated L-serine phosphate. The most favorable conformation of L-serine phosphate is found to be one where the bond sequence O—C—C—C is trans and P—O—C—C gauche, and a very short hydrogen bond is formed between an oxygen atom of the phosphate group and a hydrogen atom of the ammonium group.For hydrated L-serine phosphate, a bridge-type hydration in which a water molecule links a phosphate oxygen and an ammonium hydrogen displays particularly low energy. In the four-hydrated L-serine phosphate anion, the most favorable conformation is such a bridged one having a rather extended configuration with regard to the bond sequences O—C—C—C and P—O—C—C.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560350305
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Ab initio SCF study of the interaction between L-serine phosphate and ammonia (1989)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 587-598 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possible conformational changes of L-serine phosphate due to the interaction with ammonia are investigated by means of ab initio MO-LCAO-SCF calculations, using a supermolecule approach and an STO-3G basis set. The most favorable conformation of a four-hydrated L-serine phosphate anion is found to be changed by the binding of an ammonium ion. Cointeraction of ammonia and NH4+ suggests another conformational change through the displacement of the bridging water molecule of the polyhydrated L-serine phosphate anion.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560360506
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    139La and63Cu-NQR of high-T c oxide superconductors (1989)
    Springer
    Hyperfine interactions 50 (1989), S. 583-591 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Nuclear quadrupole resonances (NQR) of139La in La2−xMxCuO4 (M=Ba, Sr) and63Cu in YBa2CU3O7 have been investigated with substitution of Cu by magnetic impurities. For La-system, the strong enhancement of the nuclear relaxation rate, 1/T 1 atT c *≈10 K (suggesting the occurrence of magnetic instability with hole-doping), is suppressed by 3D-antiferromagnetism induced by magnetic impurities. In the superconducting region, fluctuations of Cu moments at low temperatures remain extremely fast as at high temperatures. For Y-system, Fe-ions are substituted for both Cu(1) and Cu(2) sites, But Co-ions are preferentially substituted to Cu1 sites. The peaks in the relaxation rate of Cu indicate the appearance of magnetic ordering without destroying superconductivity for the 0.5%-Fe doped sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407695
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    Paper (German National Licenses)
    Fulltext
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