Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Geometrical models for the high-frequency dielectric properties of brine saturated sandstones (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 2575-2582 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the MHz–GHz range, geometrical effects associated with platy grains (e.g., clay particles in sandstones) are especially important in determining the complex dielectric function, ε(ω), of rocks. We consider two classes of geometrical models based on rather different pictures for the spatial arrangement of the clay particles. In the bimodal model, spherical and platy grains (with a single aspect ratio) are randomly dispersed throughout the system while in the coated grain consolidation model the platy grains are confined to a thin layer at the pore grain interface. Calculations based on these models are compared with experimental data on five sandstones and the coated grain solidation model is generally found to be in better agreement. In sandstones exhibiting the strongest frequency dependence in ε(ω), we find that a continuous distribution of platy grain aspect ratios is required to obtain a satisfactory fit to the experimental data. Such distributions are easily treated within the coated grain consolidation framework.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341645
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Spin waves in the uniaxial spin glass system Fe1−xMgxCl2 (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 4077-4079 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report an inelastic neutron scattering study of the uniaxial dilute antiferromagnets Fe1−xMgxCl2, for x=0.3, 0.45, and 0.6. The first two samples have long-range antiferromagnetic (AF) order. Their spin-wave peaks are broadened by the exchange fluctuations. The x=0.6 sample orders like an Ising spin glass with a very short AF correlation length (ξ≈10 A(ring)). For wavelength λ(approximately-less-than)ξ, spin wave peaks are similar to the dilute antiferromagnets, but for λ(approximately-greater-than)2ξ, the peak sharpens up and becomes resolution limited at the zone center. We give a simple explanation for this behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338533
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Coexistence of antiferromagnetism and spin-glass ordering in the Ising system Fe0.55Mg0.45Cl2 (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 3462-3464 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Fe1−xMgxCl2 is a diluted Ising antiferromagnet with competing first- and second-neighbor exchange interactions. For x≈45, the system undergoes a Néel transition at TN ≈7.4 K and a reentrant spin-glass transition at Tsg ≈3.0 K. From neutron scattering experiments we find that (i) the antiferromagnetic Bragg peak persists down to 1.2 K, well below Tsg; and (ii) the diffuse scattering becomes temperature independent below about 6.0 K, with the correlation length frozen at about 2.8 lattice spacings. These results suggest that long-range antiferromagnetic order and spin-glass-like short-range order coexist. Such a behavior is predicted by the infinite-range model for spin glasses with strong uniaxial anisotropy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.335080
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Studying fractal geometry on submicron length scales by small-angle scattering (1988)
    Springer
    Mathematical geology 20 (1988), S. 655-665 
    Details
    ISSN: 1573-8868
    Keywords: Pareto distribution ; scale invariance ; self-similarity ; self-affinity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Recent studies have shown that internal surfaces of porous geological materials, such as rocks and lignite coals, can be described by fractals down to atomic length scales, In this paper, the basic properties of self-similar and self-affine fractals are reviewed and how fractal dimensions can be measured by small-angle scattering experiments are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00890582
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...