Modeling of Molten Corium Oxidation in the Presence of an Oxide Crust on the Melt Surface

Technical Physics - In the case of a severe accident at a nuclear power plant with light-water reactors, the most effective method for localization of the formed melt (corium) is its retention in...     

Exploring the Effect of Ligand Structural Isomerism in Langmuir–Blodgett Films of Chiral Luminescent EuIII Self‐Assemblies

Here we have investigated the influence of the antenna group position on both the formation of chiral amphiphilic Eu^III‐based self‐assemblies in CH₃CN solution and, on the ability to form monolayers on the surface of quartz substrates using the Langmuir–Blodgett technique, by changing from the 1‐naphthyl ( 2(R) , 2(S) ) to the 2‐naphthyl ( 1(R) , 1(S) ) position. The evaluation of binding constants of the self‐ assemblies in CH₃CN solution was achieved using conventional techniques such as UV/Visible and luminescence spectroscopies along with more specific circular dichroism (CD) spectroscopy. The binding constants obtained for EuL , EuL₂ and EuL₃ species in the case of 2‐naphthyl derivatives were comparable to those obtained for 1‐naphthyl derivatives. The analysis of the changes in the CD spectra of 1(R) and 1(S) upon addition of Eu^III not only allowed us to evaluate the values of the binding constants but the resulting recalculated spectra may also be used as fingerprints for assignment of the chiral self‐assembly species formed in solution. The obtained monolayers were predominantly formed from EuL₃ (≈85 %) with the minor species present in ≈15 % EuL₂ .     

On the nature of optically controlled delay of a stokes pulse amplified by stimulated Brillouin scattering in optical fiber

In this work we show through an analytic solution of the set of two coupled dynamic equations for the slowly varying amplitudes of the Stokes optical field and material density in stimulated Brillouin scattering (SBS), its analysis and a set of experiments, that the SBS-induced delay of an output Stokes pulse which is amplified by the SBS interaction is due exclusively to the inertia of the acoustic wave excitation.     

Optical methods for ecological mapping of urban areas

The results of the study of spectral characteristics of tree crops of Samara city as a method for measuring air pollutant concentrations. Even-age plantings of European white birch at ten points of Samara near main motorways were chosen as objects of study. It was shown that the ratio K of the light backscattering intensities at wavelengths of 750 and 550 nm is sensitive to pollutants and insensitive to measurement conditions. The relation between the coefficient K and the leaf chlorophyll concentration and their dependence on the total concentration of anthropogenic substances characteristic of internal-combustion engine exhausts (CO, NO₂, SO₂) were experimentally determined. The carbon oxide concentration has the strongest effect on the coefficient K. This makes it possible to apply the described method tested by the example of Samara city to ecological mapping of city territories.     

Study of the electronic structure of Al(III) and Zn(II) complexes with organic ligands by quantum chemistry and photoelectron spectroscopy methods

Photoelectron spectra of aluminum complexes with 8-oxyquinoline (Alq ₃) and zinc complexes with N, N′-(o-phenylene)-bis(salicylidenediamine) (ZnSaloph) were measured on a photoelectron spectroscopy station at the Kurchatov Centre for Synchrotronic Radiation over the range of photon energies from 10 to 100 eV. Thin films of these compounds (∼20 nm thick) prepared by thermal evaporation onto glass substrates covered with transparent electroconductive layer of solid solution of tin and indium oxides (In₂O₃, SnO₂, ITO) were used as the objects of this study. The spectra of the valence band of these compounds and Al 2p level were measured. The data of quantum chemical calculations of the electronic structure obtained by the density functional theory are in good agreement with the experimental photoelectron spectra. Analysis of performance efficiency of the device was carried out on the basis of the results of calculation. This procedure does not result in decomposition of samples in the process of investigation and may be used for studying the electronic structure of coordination compounds with organic ligands in films.     

Mass spectrometric study of the overheated vapor over nickel(II), Copper(II), and Zinc(II) <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-Ethylenebis(salicylaldiminato) complexes

A mass spectrometric study of the overheated vapor over the nickel(II), copper(II), and zinc(II) N,N′-ethylenebis(salicylaldiminato) complexes between 300 and 865°C has been carried out. Throughout this temperature range, the overheated vapor over all of the complexes contains no ions heavier than the molecular ion [MO₂N₂C₁₆H₁₄]⁺. At ∼600°C, Cu(salen) and Zn(salen) interact with the structural material of the double-chamber two-temperature effusion cell (Kh18N10T steel). The complexes are thermally very stable. The fragmentation pattern of the chelates under electron-impact ionization is metal-dependent.     

Isotherm of α-tocopherol adsorption on acid-activated clinoptilolite tuff

Adsorption of α-tocopherol from ethanol solution on clinoptilolite tuff activated with 4.0 M HCl is studied. α-Tocopherol adsorption isotherm is analyzed using the Langmuir, Freundlich, and Redlich-Peterson adsorption theories. The adsorption of α-tocopherol from dilute solutions on this sorbent is ascertained to be described by the Langmuir model.     

Dynamics of the Stokes pulse in a Brillouin amplifier

We show that the output Stoke pulse from a continuously (CW) pumped stimulated Brillouin scattering (SBS) amplifier is the sum of the transmitted input Stokes pulse, which propagates undistorted through the medium without amplification and additional delay, and of a Stokes shifted pump signal reflected by the electrostrictively induced acoustic wave, which contributes to the Stokes output signal with a delay determined by the time required for build up of the acoustic wave.     

Side Reactions in the Liquid-Phase Cyclohexanone Ammoximation

Influence of metal ions on hydrogen peroxide decomposition on the liquid-phase ammoximation of cyclohexanone was studied in homogeneous and heterogeneous (over titanium silicalite) conditions. The latter reaction is accompanied by side reactions, which deactivate the catalyst. Deactivation behavior is discussed.