Determination of the Isotopic and Elemental Composition of the Core of an Armor-Piercing Projectile

The elemental and isotopic composition of the core material of a hard-core projectile that had fallen onto the ground was studied by secondary-ion mass spectrometry, alpha and gamma spectrometry, X-ray photoelectron spectroscopy, and scanning electron microscopy with X-ray microanalysis. The environmental aspect of the use of depleted uranium ammunition in Yugoslavia is discussed.     

Spatial scale-dependent tracer diffusion in bulk polycarbonate studied by holographic relaxation

The diffusion of a photochromic dye tracer in polycarbonate was studied by a holographic relaxation technique (forced Rayleigh scattering) at temperatures close to the glass transition temperature. By varying the holographic grating period the results could be interpreted via the spatial scale dependence of apparent diffusion coefficients within a two-state diffusion model. This indicates inhomogeneities on the scale of a few micrometers in the polymer glass.     

Experimental setup to study catalysts by combined pulse microcatalytic and ESR spectroscopic methods

A setup consisting of an ESR spectrometer and a pulse microcatalytic installation is suggested for simultaneous kinetic and spectral measurements directly in catalytic processes.

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Holographic polymer materials with diffusion development: Principles, arrangement, investigation, and applications

We present a review of information that has been published in the scientific literature on the mechanism of formation (development, enhancement) of holograms at the expense of the photochemical attachment of phenanthrenequinone molecules and other compounds to polymer chains and diffusion mixing of unreacted molecules, on different types of light-sensitive materials that realize this mechanism, on the application of these materials to create volume holographic elements, on recording of information, and for research purposes.     

The Existence of the Thermodynamic Limit for the System of Interacting Quantum Particles in Random Media

The thermodynamic limit of the internal energy and the entropy of the system of quantum interacting particles in random medium is shown to exist under the crucial requirements of stability and temperedness of interactions. The energy turns out to be proportional to the number of particles and/or volume of the system in the thermodynamic limit. The obtained results require very general assumptions on the random one-particle model. The methods are mainly based on subadditive type of inequalities.     

Visualization of type II fiber Bragg gratings induced in a birefringent fiber with an elliptical stress cladding

Experimental results on visualization of type II fiber Bragg gratings induced in a birefringent fiber with an elliptical stress cladding are presented. The gratings are recorded by a single pulse of an excimer KrF-laser by means of the phase-mask method. Images of the gratings are obtained in a bright field using contrasting techniques such as differential interference contrast and dark field. It is shown that single-pulse recording forms several type II Bragg gratings in the optical fiber. The spatial profile of these gratings corresponds to the phase mask period. Microcracks due to which type II gratings are induced are localized both on the boundaries between the fiber core and claddings surrounding it and at some distance from them.     

The shape of the relaxation curve in diffusion measurements with the aid of photoinduced gratings

It is shown by experimental examples how the postexposure relaxation of a photochemically induced grating used to study the diffusion of a molecular probe by the holographic relaxation method depends on the molecular mechanism of the grating formation, medium inhomogeneity, and relative shift of grating parts, as well as the grating strength. The adequate consideration of the factors influencing the observed behavior of the grating provides for the possibility not only to correctly retrieve information about the diffusion, but also to extend the range of studied phenomena.     

Hydrocarbon specificity in the selective catalytic reduction of NOx over Cu-ZSM-5 and Co-ZSM-5 catalysts

Transformation of surface nitrates under CH₄ (CH₄+O₂) was found to ensure steady-state activity of Co-ZSM-5 in the selective catalytic reduction of nitrogen oxides by methane (CH₄-SCR). For Cu-ZSM-5, such species are mainly converted into NO. Relaxation of the coordination sphere due to oxygen and NO adsorption, stability of C,N-containing intermediates and activation routes of hydrocarbons (methane, propane) were analyzed as factors determining catalytic properties of Cu and Co cations.