Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1970-1974  (2)
Datenquelle
Materialart
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Heat exchange in liquid helium by phonon tunneling through very thin plates (1971)
    Springer
    Journal of low temperature physics 4 (1971), S. 263-271 
    Details
    ISSN: 1573-7357
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Thin plates with a thicknessd smaller than the phonon mean-free path can be used to increase the heat exchange in 3 He- 4 He refrigerators at very low temperatures. The resistanceR for the heat current density of these plates is theoretically investigated. For plates withd still larger than the dominant thermal-phonon wavelength λ T in the plate,R is given by twice the Kapitza resistance. Ford ≈ λ T the resistanceR decreases due to phonon tunneling. Ford ≪ λ T there exists a region whereR varies asT −1, in contrast to theT −3 dependence for thicker plates. Numerical calculations are carried out for copper plates immersed in pure 4 He. The results show that one obtains a large increase of the heat exchange due to phonon tunneling for plates with a thickness of a few microns at temperatures in the millidegree range.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00629713
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    A quantum mechanical determination of the superfluid density (1972)
    Springer
    The European physical journal 14 (1972), S. 324-335 
    Details
    ISSN: 1434-6036
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The constituting conservation laws for a superfluid are quantum mechanically derived. Using thermodynamic relations the superfluid density is model-independently expressed in terms of reduced-density matrices. The general relation is illustrated for the Bogolubov model, and for two other approximations for the two-particle reduced-density matrix. The resulting relations between the densities of the super component and of the condensate are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02422689
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...