Showing papers in "Physica D: Nonlinear Phenomena in 1973"

TL;DR: In this article, a modified version of the Enskog equation is proposed to describe the time dependence of the single-particle distribution function in a dense gas of hard spheres, which is not restricted to small spatial non-uniformities and may be used to derive higher-order hydrodynamic equations.

TL;DR: In this paper, the frequency-independent volume viscosity in N2, CO, CH4 and CD4 at temperatures ranging from 77 to 300 K was determined from sound-absorption measurements.

TL;DR: In this paper, the effect of stochastic frequency fluctuations on the brownian motion of a harmonic oscillator driven by white noise was investigated and the equilibrium values of the mean square displacement, of the autocorrelation function and of the spectral energy density were calculated explicity when the frequency is a two-valued Markov process.

TL;DR: In this paper, the authors apply the Kikuchi approximation to the order-disorder transformations in an fcc binary alloy that is assumed to conform to a generalized Ising model, taking formally into account all interactions between 2, 3 and 4 nearest neighbours.

TL;DR: In this paper, a statistical theory for the wave vector and frequency-dependent dielectric tensor of a non-polar fluid is given, which is not restricted to small values of the polarizability per unit unit of volume.

TL;DR: In this paper, the authors measured the cross sections for K-shell X-ray emission for 0.2-18 keV electrons incident on CH4, N2, O2, Ne and Ar.

TL;DR: In this article, the normal solution of the modified Enskog equation for mixtures is obtained, the Navier-Stokes equations are derived and explicit expressions for the linear transport coefficients which follow, are shown to satisfy the laws of irreversible thermodynamics.

TL;DR: The coefficient of shear viscosity of fluid argon has been measured at temperatures from 85 to 298 K and at pressures up to 34 MN/m2 using the torsional crystal viscometer as discussed by the authors.

TL;DR: In this paper, the contributions of the 3D and conduction electrons to the momentum density of photon pairs from positron annihilation in copper and ferromagnetic iron have been calculated.

TL;DR: An alternative phenomenological theory of the dielectric properties of thin films is given in this article, where the film is described by a two-dimensional surface using surface dielectrics coefficients.

TL;DR: In this paper, the authors introduced the concept of subdynamics to study the behavior of large systems, and formulated the usual thermodynamic description of such systems can be formulated in a subspace οП of the Liouville space.

TL;DR: In this paper, a thermodynamic theory for some types of dielectric and magnetic relaxation phenomena is developed, where a polar and an axial vector field occur as internal thermodynamic degrees of freedom and that these fields influence the polarization and magnetization, respectively.

TL;DR: In this paper, the limits to the degree of enhancement for non-Kramers ions of the lanthanide group, with particular reference to enhanced nuclear cooling, were explored by examining some special configurations of low-lying electronic energy levels.

TL;DR: In this paper, the transfer matrix of the free-fermion model is diagonalized by operator methods, and the spectrum of eigenvalues near the maximum is studied in some detail.

TL;DR: In this paper, a transformation in classical lattice statistics which generalizes the weak-graph theorem and includes the duality transformation is described, where the energy of the configurations is expressed by a function of "quantum numbers" which are subject to certain constraints.

TL;DR: In this article, relative cross sections have been measured for the atom-atom collision process Na + I → Na + + I − at kinetic energies from 13 to 85 eV, showing two types of oscillating features: Stueckelberg oscillations due to the interference of scattering from different potentials inside the pseudo-crossing of the covalent and ionic potential curves.

TL;DR: In this article, a general formulation of the relationship between macroscopic and microscopic nonlinear dielectric response functions is presented, and the results are in agreement with and justify previous theoretical and experimental data for local field corrections for the nonlinear susceptibilities χ 2 and χ 3, and for a contribution proportional to (χ 2 ); 2 to χ3 eff,.

TL;DR: In this paper, the transfer matrix of the zero-field free-fermion model is diagonalized by operator methods, which is a special case of the eight-vertex model solved by Baxter, but has the advantage that an easy survey of eigenvalues and eigenvectors is obtainable.

TL;DR: In this article, a necessary condition for high superconducting transition temperatures in multicomponent phases has been identified: crystallographic instabilities seem to be a necessary and sufficient condition.

TL;DR: In this article, the conservation laws of rest mass and energy-momentum for an non-equilibrium gas mixture of n components are derived on the basis of the relativistic form of Boltzmann's transport equation.

TL;DR: In this paper, the reflectance R and transmittance T of an infinite square lattice of polarizable nonpolar particles with retarded dipole-dipole interactions are rigorously calculated.

TL;DR: In this article, the spontaneous emission of atomic bromine and iodine was experimentally investigated by Fourier transform spectrometry and the 2P12 → 2P32 transitions inside the np5 configuration, which are forbidden with respect to electric dipole radiation, were observed at σ = 3685.15 cm−1 for bromines and at ε = 7602.98 cm− 1 for iodine.

TL;DR: In this article, a relativistic method to calculate transport coefficients for arbitrary particle interaction is developed, where the heat conductivity, the shear viscosity and the volume volumetric viscosities are expressed in terms of relativism omega integrals.

TL;DR: In this paper, the low-density vicosity of CH4 (25-200°C), CF4(25-600°C) and SF6 (25−300°C).

TL;DR: In this paper, the authors reported new measurements of the viscosity of oxygen and air, and of the binary mixtures O2-Ar, O2Kr and N2-O2, together with check values for the pure gases which appear in them.

TL;DR: In this paper, the generalized fluctuation-dissipation theorem for brownian motion in incompressible liquids is also valid for the case of compressible fluids, and it is shown that the autocorrelation functions for random force and velocity change with degree of compressibility in a continuous fashion.

TL;DR: In this paper, the sum and difference angular correlations measured on five differently oriented single crystals are combined and unfolded to yield the three-dimensional density distributions up to the l = 8 term.

TL;DR: In this article, a theory of the low-frequency depolarized-light scattering spectra of fluids of nonspherical molecules is obtained, where the intensity of the scattered light is proportional to the polarizability-density autocorrelation function.

TL;DR: In this paper, it was shown that the study of the quantum hydrogen-atom problem is equivalent to that of a quantum harmonic-oscillator problem in four dimensions, restricted by a superselection rule which results from the invariance of the physical states under the transformations of a one-parametric subgroup of O(4), the kernel of the transformation used.

TL;DR: In this paper, the authors derived explicit expressions for the free energy per spin, the z component of the magnetization per spin in the finite a-cyclic XY model for the thermodynamic limit.