Showing papers in "Physica D: Nonlinear Phenomena in 1969"

TL;DR: In this paper, a lower bound for the time average of the autocorrelation function of a phase function X(q1,…,Pn), defined for canonical ensembles of classical systems, is obtained in terms of averages involving constants of the motion of the systems considered.

TL;DR: In this article, exact expressions for the isothermal elastic constants, C T 11, C T 12, and C T 44, were derived for cubic crystals whose molecules interact with pairwise-additive central forces.

TL;DR: In this article, a discussion is given on the results of heat capacity measurements below 2 K on rare-earth double oxides with the general formula R2M2O7, where R stands for Nd, Tb, Dy, Ho, Er and Yb and M2 stands for Ti4+2, Sn4 + 2, Zr4+ 2 or Ga3+Sb5+, respectively.

TL;DR: In this paper, the authors introduce operateurs de projection Π(j) ρ of the fonction de distribution ρ (ou la matrice densite) and show that these projections satisfy des equations separees.

TL;DR: In this paper, the binary-collision expansion for potentials consisting of a hard core and a soft tail is discussed and the restrictions to their applicability are determined, and the different expressions so far proposed are critically examined.

TL;DR: In this article, the authors measured the noise on small samples of continuous gold films as a function of sample thickness and of temperature, and showed that the noise is inversely proportional to the total number of electrons.

TL;DR: In this article, the exact cross sections for excitation of helium to n1S (n = 3, 4, 5 and 6), n1P (n 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 41) and n3D

TL;DR: In this article, the profile of a Cu I spectral line, excited by bombardment with 80 keV Ar ions, was measured and the Doppler profile showed that the light-emitting particles have energies in the keV region.

TL;DR: The magnetic properties of two antiferromagnetic cobalt compounds, K2CoF4 and Rb2CoFs4, were studied in this paper, and it was shown that the magnetic exchange between the cobalt ions is strongly anisotropic, making the two compounds good examples of the two-dimensional Ising model.

TL;DR: In this article, the exact intensities of scattered projectile and recoil ions resulting from large-angle collisions of 60 and 90 keV Ar + ions in a (100) surface of a solid Cu target are presented.

TL;DR: In this paper, two alignment mechanisms have been investigated by means of a Monte Carlo model and the quantitative dependence of both angular momentum alignment and axis alignment on grain shape and velocity has been established with an accuracy of 5 to 10 percent.

TL;DR: In this article, the relative abundances of multiply charged ions formed by electron impact (2-16 keV) on some noble gases were measured using a charge analyzer with 100% transmission.

TL;DR: In this article, the noise generated in an optical mixer operating at 6328 A has been calculated and measured, and it was found that the amplified noise of the incoming radiation gives a significant contribution to the output noise, and that this contribution is independent of the intensity of incoming optical signal.

TL;DR: In this article, the relevant linear Burnett coefficients for a polyatomic gas in a magnetic field are explicitly evaluated by truncating in a standard way the tensorial expansions occurring in the solution of the first-order Chapman-Enskog equations for the thermal conductivity and viscosity problems.

TL;DR: In this paper, the authors derived the relationship between d.c.current (i), V and magnetic field (B⊥) for a double junction, taking the self-inductance (L) of the area (O) embraced by the contacts into account.

TL;DR: In this paper, exact expressions for the adiabatic elastic constants, CS11, CS12 and CS44, were derived for cubic crystals composed of particles interacting with pairwise additive central forces.

TL;DR: In this article, a quantum-statistical theory of multicomponent plasmas is applied to a partially ionized gas in thermal equilibrium, and the theory is developed on the basis of two different models of the real plasma.

TL;DR: In this paper, an extension of the group theory treatment of the Schroedinger equation of an electron in the presence of an electrostatic, periodic field and a uniform magnetic field is presented.

TL;DR: In this paper, the authors reported that for entropies below 0.38R, χ reaches a constant and maximum value of 1/N for both samples, where N is the demagnetizing factor.

TL;DR: In this article, the authors have studied the spectral spectra of CH 4 and C 2 H 2 excited by proton impact and two new systems ascribed to 1 △→ 1 п and 3 Σ→ 3 п of CH + appear and they have been analysed.

TL;DR: In this paper, a proof of the Lorentz-invariance of the distribution function f(r, p, t) in one-particle phase space is given.

TL;DR: In this paper, a rotating-crystal spectrometer was used to study cyclohexane and cyclopentane in the liquid and solid phases by the inelastic scattering of 4 A neutrons using a rotating crystal spectrometers.

TL;DR: In this paper, the specific heat of annealed niobium wires with a resistance ratio of 145 was measured at constant magnetic fields in the temperature range from 1 K to 10 K.

TL;DR: In this paper, it was shown that the strong D condition provides one of the boundary conditions needed to define the flow; this conclusion was similar to one reached by Axford 6 ) when he was studying the expansion of a spherically symmetrical HII region around a star.

TL;DR: In this article, lineshift and linewidth of the 19 F NMR of a single crystal of K 2 NiF 4 have been measured in the paramagnetic region between 100 and 300 K and the value for the hyperfine coupling between fluorine nuclear and the neighbouring nickel electron spin has been derived.

TL;DR: In this paper, the authors derived relativistic reciprocal relations between the cross effects of heat conduction and diffusion from time reversal invariance for a gas mixture, which obeys the linearized relativism transport equation.

TL;DR: In this article, the dispersion relations, transition temperatures and dynamical structure factors for inelastic neutron scattering by spin waves are derived for antiferromagnetscal with the corundum structure.

TL;DR: In this paper, the velocity of ultrasonic pulses in liquid argon along seven isotherms at temperatures ranging from 100 K to 150 K and pressures up to 500 atm was measured.

TL;DR: In this paper, the growth and motion of silicon carbide particles were computed for a set of densities in the atmospheres, and it was shown that the particles are able to escape in case the surface acceleration is sufficiently low.

TL;DR: In this paper, the amplitude distribution of 1/f noise was investigated by displaying the noise on an oscilloscope, and scanning the picture with a movable slit; the distribution curve is gaussian; its variance does not fluctuate with time.