Development of methods for multidimensional measurements in the optical investigation of surface

The problems of developing methods for multidimensional (multichannel) data acquisition as applied to the optical study of the surface are considered. Unlike conventional methods of transition to multidimensional measurement, which employ mechanical scanning, the use of new-type instruments that allow for coordinate-sensitive and time measurements are discussed. Both the sensitive elements (detectors) and the instruments (hyperspectrometers) created for multidimensional coordinate-spectrum-time measurements are described. The application of hyperspectrometers makes it possible to increase manyfold the information content of measurements. The fluorescence of dye molecules deposited on the surfaces of germanium and silicon preirradiated by a laser beam is studied. The scattering spectra from these samples are examined.     

First chiral [2.2]paracyclophane-derived phosphite ligands: synthesis and application in asymmetric reactions

First representatives of chiral phosphite ligands derived from 4,5-dihydroxy[2.2]paracyclophane have been synthesized. A possibility of the use of these compounds in the reactions of asymmetric Pd- and Ir-catalyzed allylic amination of 1,3-diphenylprop-2-enyl acetate with pyrrolidine and Rh-catalyzed hydrogenation of dimethyl itaconate has been demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 132–134, January, 2008.     

Advances in the studies of bisphosphorylated dihydric phenols

The data on the synthesis, structure, and chemical properties of bisphosphorylated dihydric phenols are summarized. All the currently known methods for the synthesis of the systems in question are shown. Specific features of their structure, chemical and complexation properties, as well as areas of application of these compounds were analyzed.     

Sodium and potassium halides as catalysts for the addition of carbon dioxide to epoxides: the effect of co-solvents

A complex study of sodium and potassium halides as catalysts of the addition of CO₂ to epoxides to yield organic carbonates was carried out. The activity of these metal iodides was investigated. The conditions allowing achievement of a quantitative conversion of epoxides into carbonates were found by varying the temperature, carbon dioxide pressure, and available co-solvents.

     

Effect of the design parameters and the atmosphere composition on the electric discharge shape

The effect of the atmosphere composition and the electrode material and design on the discharge shape and variation in the process of its development and in the steady-state regime is investigated. Graphites of different modifications, tungsten, and copper were used as electrode materials and air, argon, and helium as baseline atmospheres. It is established that the discharge shape (the shape of the glow region in the interelectrode gap) considerably depends on the actual composition of the atmosphere which is determined by the composition of the baseline atmosphere and additions introduced in the interelectrode gap either upon electrode evaporation or with a special purpose. The electrode material influences the steady discharge shape via precisely these additions.     

Statistical characteristics of photon distributions in a semi-infinite turbid medium: Analytical expressions and their application to optical tomography

The paper focuses on the determination of statistical characteristics of photon distributions in a semi-infinite turbid medium, specifically the photon average trajectory and the root-mean-square deviation of photons from the average trajectory, with an approach based on the diffusion approximation to the radiative transfer equation. We show that the Dirichlet and Robin boundary conditions used for this purpose give close results. We derive exact analytical expressions for the case of the Dirichlet boundary condition. To demonstrate the practical value of our results we consider approximate solution of the inverse problem of time-domain diffuse optical tomography with the flat layer transmission geometry. The problem is solved with the method of photon average trajectories which are constructed with analytical expressions derived for a semi-infinite medium.     

IR spectrum of the closed form of indolinospironaphthooxazine

IR absorption spectra of indolinospironaphthooxazine (ISNO) are presented. The geometric structure and normal coordinates of the ISNO molecule have been calculated using a quantum mechanical DFT method. The IR spectrum of ISNO in its original spiro form has been interpreted for the first time. Four normal modes in the range 800–1200 cm^–1 with the largest amplitudes of C_spiro–O bond change are identified. The excited ISNO molecule spiro form may experience photoconversion to the merocyanine form through them.     

Bifurcation analysis of a viscoelastic fluid heated from below

Convection of a viscoelastic fluid in a square domain heated from below is investigated for the case of nondeformable free surfaces. To describe the rheological behavior of the fluid the generalized Oldroyd model is used. A weakly nonlinear analysis is performed in order to determine the character of branching for both the monotonic and oscillatory modes. We also perform a reduction of the boundary value-problem to the set of nonlinear amplitude equations. The analysis of this dynamic system demonstrates the onset and competition of five convection modes.     

Onset of convection in a horizontal fluid layer in the presence of density inversion under given heat fluxes at its boundaries

The onset of convection in a horizontal fluid layer in the presence of density inversion is studied under given heat fluxes at the layer boundaries. The stability diagram is obtained and the nature of disturbances is studied in the linear approximation. Depending on the density maximum position within the layer the instability may be both long-wave and cellular in nature.