Einstein gravitation from scalar nonsingular sources alone

In the light of Einstein's equations a system only containing two scalar fields is considered: One is of long range and attractive, the other is of short range and repulsive. The sources of these fields are taken to be nonsingular and spherically symmetric. All components of the energy-momentum tensor are continuous. A static solution of the equations is obtained in the weak-field approximation. The source of the gravitational field shows a finite concentration on the center of symmetry and dilutes monotonically to zero outwards. A Schwarzschild-type gravitation is found at infinity.     

Note On the equality of star products

We study the problem of finding conditions for two star products of n vectors to be equal when the vectors in each star product are not linearly independent, and the problem of finding conditions for one star product to be zero. We reprove results of M. Marcus and J. Chollet in a very simple way. We present also some open problems.     

Spectral density of surface states: Clean W(001) surface

The transfer matrix approach is applied to calculate the spectral density of electronic states for the W(001) surface. We use a tight-binding hamiltonian with a nine function basis: 6s, 6p and 5d. Results for $\text{k}$ points along the Σ and ? symmetry lines are presented for occupied states. Both surface and bulk features of the spectral density are in good agreement with angularly resolved photoemission spectra.     

Hyperfine spectroscopic study of the metal-insulator transition in V2O3

The metal-insulator (M-I) transition in vanadium sesquioxide V₂O₃ has been investigated by time differential perturbed angular correlation measurements of the electric fieldgradient (EFG) and the magnetic hyperfine field at dilute¹¹¹Cd impurities. The EFG undergoes a first-order change at the M-I transition at T_t=160 K, but does not reflect the high temperature resistivity anomaly. The increase of the EFG with temperature in the metallic phase can be attributed to thermal variations of the oxygen sublattice. The temperature dependence of the magnetic hyperfine field in the insulating phase follows a Brioullin function with a saturation value of H_hf(O)=15 KOe and an extrapolated Neel temperature, which, depending on the impurity concentration, varies between 188 and 230 K.     

Flexural-flexural oscillations of Beck's column subjected to a planar harmonic excitation

The non-linearly coupled flexural-flexural oscillations of a non-conservative column with two independent load parameters are investigated by analytical methods with the objective of determining the quantitative and the qualitative behavior of the response. The column is subjected to a planar periodic distributed load whose frequency is near the eigenfrequency of its free bending oscillations. The analytical results of the analysis are compared with those obtained by numerical integration of a set of non-linear differential equations obtained by the application of Galerkin's method to the original equations.     

Polarography of an acidic degradation product from cephalexin

2-Hydroxy-3-phenyl-6-methylpyrazine is identified as the product obtained by acidic degradation of cephalexin in the presence of formaldehyde. In 5M hydrochloric acid this product gives a well-defined reduction wave with a half-wave potential of -0.45 V vs. SCE. The wave is irreversible and diffusion-controlled. The diffusion current shows a linear relation with the cephalexin concentration and can be used for determination of cephalexin in plasma.     

An accurate relativistic universal Gaussian basis set for hydrogen through Nobelium without variational prolapse and to be used with both uniform sphere and Gaussian nucleus models

An accurate relativistic universal Gaussian basis set (RUGBS) from H through No without variational prolapse has been developed by employing the Generator Coordinate Dirac-Fock (GCDF) method. The behavior of our RUGBS was tested with two nuclear models: (1) the finite nucleus of uniform proton-charge distribution, and (2) the finite nucleus with a Gaussian proton-charge distribution. The largest error between our Dirac-Fock-Coulomb total energy values and those calculated numerically is 8.8 mHartree for the No atom.