On the uniform convergence of special sine integrals

We study the uniform convergence of sine integrals of measurable functions on the open half-line. We also extend results of F. Móricz and give examples for appropriate functions.     

Theoretical study of the role of solvent Stark effect in electron transitions

The possible influence of the solvent Stark effect (SSE) on the solvatochromic shift in electron transitions has been analyzed by using the ASEP/MD (averaged solvent electrostatic potential from molecular dynamics) method. With this purpose, four molecules, two polar (acrolein and formaldehyde) and two non-polar (p-difluorobenzene and trans-difluoroethene) have been studied in solvents of diverse polarity. Independently of the nature of the system we found that the contribution of SSE on the average value of the solvent shift or on the multipole moment values is negligible. In the case of centro-symmetric molecules, our results permit to discard the SSE as cause of the solvent shift found, which must be assigned to the electrostatic interaction of the solute quadrupole and higher multipoles with the solvent. As the SSE values provide also a measure of the errors introduced by the mean field approximation (MFA), these results indicate that MFA permits a very accurate determination of the solvent shift at the same time that it reduces drastically the computational cost. Finally, a new procedure suited to the ASEP/MD method has been presented that permits to estimate the inhomogeneous broadening of spectral bands, complementing the information provided by mean field theories. This procedure does not need additional quantum calculations and its computational cost is minimal.     

Characteristic electron loss spectra and electronic structure of thallium chloride

The bands, state densities N(E), and permittivity are theoretically found for TlCl crystals. On the basis of the experimental characteristic electron loss spectra, the spectra of the complete set of optical functions including permittivity and bulk electron loss spectra are calculated and decomposed into components. The obtained data are compared with the well-known theoretical results. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 8–11, June, 2008.     

The specific contribution of phosphorus in dendrimer chemistry

Besides properties commonly found for all types of dendrimers, phosphorus-containing dendrimers possess some specific properties seldom or never found for other types of dendrimers. Emphasis will be put on these specificities.     

High resolution 2D 1H-13C correlation of cholesterol in model membrane

High resolution 2D NMR MAS spectra of liposomes, in particular 1H-13C chemical shifts correlations have been obtained on fluid lipid bilayers made of pure phospholipids for several years. We have investigated herein the possibility to obtain high resolution 2D MAS spectra of cholesterol embedded in membranes, i.e. on a rigid molecule whose dynamics is characterized mainly by axial diffusion without internal segmental mobility. The efficiency of various pulse sequences for heteronuclear HETCOR has been compared in terms of resolution, sensitivity and selectivity, using either cross polarization or INEPT for coherence transfer, and with or without MREV-8 homonuclear decoupling during t1. At moderately high spinning speed (9 kHz), a similar resolution is obtained in all cases (0.2 ppm for 1H(3,4), 0.15 ppm for 13C(3,4) cholesterol resonances), while sensitivity increases in the order: INEPT < CP(x4) < CP + MREV. At reduced spinning speed (5 kHz), the homonuclear dipolar coupling between the two geminal protons attached to C(4) gives rise to spinning sidebands from which one can estimate a H-H dipolar coupling of 10 kHz which is in good agreement with the known dynamics of cholesterol in membranes.     

Synthetic routes to linear oligo-Tröger's bases

Derivatives of Tr?ger's base (TB) have played important roles in receptor construction due to their rigid V-shape. A new class of these compounds are the oligo-TBs, which can function as cavitands. Herein, we describe both stepwise and one-step (oligomerization) methods suitable for the preparation of linear oligo-TBs.     

Gas-liquid and gas-liquid-solid catalysis in a mesh microreactor

A microstructured mesh contactor that can offer residence time of more than minutes is used for gas-liquid-solid hydrogenations and gas-liquid asymmetric hydrogenations. Applications for catalyst/chiral inductor screening and for kinetic data acquisition are demonstrated.     

Modification of the superconducting order parameter Δ(k) by long-range interactions

It is demonstrated that the inclusion of long-range intersite interactions qualitatively modifies the dependence of a superconducting gap on quasimomentum for both s-and d-symmetry types. In particular, the order parameter of a superconducting phase with $d_{x^2 - y^2 } $ the symmetry type depends on two amplitudes and has the form Δ(k)=Δ₁(cosk _x ?cosk _y )+Δ₂(cos2k _x ?cos2k _y ). In this case, the theoretical dependence of the critical temperature on the degree of doping agrees with the experimental dependence.