caco3 nanoparticles have been synthesized via heat-treatment of a new precursor and solid state reaction. effect of calcinations temperature and quantity of surfactant on particle size has been investigated. the products were characterized by x-ray diffraction (xrd), scanning electron microscopy (sem), transmission electron microscopy (tem) and fourier transform infrared (ft–ir) spectroscopy.

The core level electron excitation and ionization spectra of thymine and adenine have been investigated by photoabsorption and photoemission spectroscopy, and the results interpreted by means of ab initio calculations using the second-order algebraicdiagrammatic construction (ADC(2)) method for the polarization propagator and the fourth-order ADC method (ADC(4)) for the one-particle Green's fun...

In drift tube linacs a beam energy spread results from the finite beam size. Radial variation of the axial accelerating field induces a beam energy spread, which, in general, will accumulate as the beam passes through successive drift tubes. This paper shows that under some conditions of periodic transverse focusing and longitudinal phase focusing, the correlation between the longitudinal and t...

This survey reviews algorithms that can render specular, i.e. mirror reflections, refractions, and caustics on the GPU. We establish a taxonomy of methods based on the three main different ways of representing the scene and computing ray intersections with the aid of the GPU, including ray tracing in the original geometry, ray tracing in the sampled geometry, and geometry transformation. Having...

We present an iterative method for simulating beam propagation in nonlinear media using Hamiltonian ray tracing. The Wigner distribution function of the input beam is computed at the entrance plane and is used as the initial condition for solving the Hamiltonian equations. Examples are given for the study of periodic self-focusing, spatial solitons, and Gaussian-Schell model in Kerr-effect medi...

The variation of current density distribution over the unit cell with direction of the incident beam gives rise to anomalous absorption and other orientation effects in electron diffraction. One of these, the electron induced x-ray emission, was demonstrated to depend on the diffraction condition already in 1962 by Duncumb [1] and a theoretical treatment based on the Bloch wave considerations w...

The analysis of Re compounds has revealed a time-dependent photoreduction during x-ray photoelectron spectroscopy (XPS) measurements. Whilst such reduction of metal ions during XPS analysis is not uncommon, this is the first time that cases specifically for rhenium have been identified in the open literature.

It is suggested that the persistent X-ray emission from the soft γ-ray repeaters is the thermal radiation of neutron stars which is enhanced by a factor of 10 or more due to the effect of a very strong magnetic field on the thermal structure of the neutron star envelope. For the thermal luminosity to be consistent with the persistent X-ray luminosity, the field strength at the neutron star surf...