WILBERT

Wildauer Bücher+E-Medien Recherche-Tool

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
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 15 (1974), S. 1-27 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction of rotons is studied by a direct examination of their orbital dynamics. It is found that upon representing rotons as point dipoles in the superfluid, obeying the Landau dispersion relation, negative energy states occur, some of which are stable and some unstable. The binding energy and effective mass of these states are found, but are too large to agree with experiment. Improvements in the Hamiltonian are explored which recognize the actual dispersion curve as well as higher moments in the interaction. Both modifications lead to binding energy and effective mass in better agreement with experiment. Scattering is also examined, and one finds that a representative roton-roton cross section may be obtained in the dipole approximation, again using Landau dispersion. The scattering cross section is shown to be in satisfactory agreement with neutron linewidths in the roton-dominated region, as well as the roton contribution to the shear viscosity.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 27 (1977), S. 687-736 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The statistical mechanics of interacting bosons is considered for cases where the interactions are sufficiently strong that the observed energy levels are dependent upon temperature. An approximate method is developed to handle the theory when energy levels are known from experiment. The results are applied to the thermodynamic properties of He II using Landau's theory of elementary excitations. This theory is assessed in several levels of approximation, and the results are compared extensively to measured thermodynamic properties. The relationship of neutron inelastic scattering measurements to these problems is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 923-935 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The flow of an electrically conducting fluid in an open channel in the presence of a strong magnetic field of oblique incidence to both the channel walls and the force of gravity is explored. This type of flow has possible applications to the protection of high heat flux surfaces in magnetic confinement fusion reactors. The governing equations of fully-developed flow are derived retaining all viscous terms. They are then solved in the strong field limit in an asymptotic, iterative fashion, carrying the first two terms in the expansion with powers of the effective Hartmann number. The asymptotic solutions for the velocity, induced magnetic field and the flow rate are compared with a numerical solution of the complete governing equations. Good agreement is seen between the asymptotic and numerical predictions of velocity and electric current distribution when the core regions are dominated by magnetic forces. One novel feature of open channel flow of this type is the existence, predicted by the asymptotic analysis and confirmed by the numerical integration, of a second-order Hartmann layer on the free surface. Its presence is required to ensure the condition of no shear stress on this boundary. Also seen is the presence of strong discontinuities across free shear layers, which form along the field lines that extend from the free surface/sidewall corner. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1432-2250
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract: If acoustically driven, a gas-filled bubble may exist indefinitely even in an unsaturated liquid through a process known as “rectified diffusion.” When the oscillation period is small compared with the gaseous diffusion time, the radius of the steadily oscillating bubble can be determined by asymptotic methods, in the way pioneered by Eller and Flynn (1965). The next term in their expansion is evaluated here and is shown to be significant if the radius of the bubble is small or if the amplitude of its oscillations is large. For the identical level of saturation and the same conditions of excitation, multiple solutions are possible. As a result of resonance between overtones of the frequency of free bubble oscillation with the frequency of the acoustic drive, there generally exist, in addition to a stable large-radius, stable small-radius states. The relevance of the present results to sonoluminescence is briefly discussed.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 331 (1988), S. 702-705 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Even though the occurrence of reversals is by now a well-established fact, largely because of the interpretation3 of marine-magnetic data, their theoretical modelling has remained difficult despite intense efforts4'13. So far, the most successful geodynamo models have been kinematic, that is, ones ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillian Magazines Ltd.
    Nature 401 (1999), S. 885-890 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A series of computer simulations of the Earth's dynamo illustrates how the thermal structure of the lowermost mantle might affect convection and magnetic-field generation in the fluid core. Eight different patterns of heat flux from the core to the mantle are imposed over the core–mantle ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 377 (1995), S. 203-209 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A three-dimensional, self-consistent numerical model of the geodynamo is described, that maintains a magnetic field for over 40,000 years. The model, which incorporates a finitely conducting inner core, undergoes several polarity excursions and then, near the end of the simulation, a ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 292 (1981), S. 232-233 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The material composing the Earth's core has often been treated as being pure iron but it is in fact an "uncertain mixture of all the elements"6. The freezing of a mixture can be very different in nature from the freezing of a pure substance7 so it is most important that the effects of composition ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 9 (1997), S. 1980-1987 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The problem of the onset of convective instability in a rapidly rotating fluid layer heated from below with various velocity boundary conditions is investigated by constructing exact solutions and by asymptotic analysis. It is shown that convective motions at sufficiently small Prandtl numbers are described in leading order by a thermal inertial wave. It is at the next order that buoyancy forces drive the wave against the weak effect of viscous dissipation. On the basis of the perturbation of the thermal inertial wave, asymptotic convection solutions for rigid boundaries can be expressed in simple analytic form. A new asymptotic power law between the critical Rayleigh number and the Ekman number is derived. In addition, solutions for both stationary and time-dependent convection are calculated numerically. Comparison between the numerical and asymptotic solutions is then made to show that a satisfactory quantitative agreement has been achieved. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...