Determination of optical parameters of a medium by the profile of backscattered radiation

The possibilities of determining the scattering coefficient, the absorption coefficient, and the scattering anisotropy parameter of strongly scattering media are analyzed on the basis of comparison of experimentally obtained profiles of backscattered radiation with the profiles calculated with help of the numerical Monte Carlo method.     

Phase Relations and Electrical Properties of Phases in Systems Na2MoO4-AMoO4-R2(MoO4)3 (A = Mg, Mn, Co, Ni; R = Cr, Fe)

The subsolidus region of ternary salt systems Na₂MoO₄-AMoO₄-R₂(MoO₄)₃ was studied. It was established that phases Na_1-x A_1-x R_1+x (MoO₄)₃, 0 x 0.2-0.3 of variable composition with rhombohedral lattice (R-3c) and ternary molybdates NaA₃R(MoO₄)₅ of triclinic crystal system (P-1) are formed in the system. The electrical characteristics of ternary molybdates and the effect of the cation nature on the homogeneity region of the phases and type of conduction were studied.     

ESR spectra of arenecyclopentadienyliron dications

ESR spectra of arenecyclopentadienyliron dications have been studied at 77 K. Arenecyclopentadienyliron cations were oxidized with SbCl₅ in CH₂Cl₂ solution at 203 K. The g_∥ and g_⊥ values have been measured and splittings of the degenerate e_2g orbitals have been calculated. The energy differences between the split components proved to be considerably smaller than that of the e^?t_1g level in the corresponding neutral complexes. They are, however, larger than the splittings of the e_2g orbitals observed in ferricinium cations.     

The Formation of Single-Photon IR Wave Packets with an Orbital Angular Momentum Using Vortex Phase Plates

Optics and Spectroscopy - Specific features of the construction and recording of axially symmetric vortex fields using diffraction optical elements, which can be used for generating single-photon...     

Wavefront formation using modal liquid-crystal correctors

Results of experiments on wavefront formation using multichannel modal correctors in an adaptive optical system with feedback are reported. Two types of correctors, one based on a glass substrate with a high-resistance layer deposited onto it and the other based on a high-permittivity ceramic substrate, are developed and investigated. The results show that it is expedient to use the correctors in applications that do not require a high speed of response.     

Photo- and electroluminescent properties of zinc(II) complexes with tetradentate Schiff bases,derivatives of salicylic aldehyde

It is studied how the introduction of various substituents into the composition of organic ligands affects the photoluminescence spectra of new zinc(II) complexes with tetradentate Schiff bases H₂L (derivatives of salicylic aldehyde (H₂SAL1, H₂SAL2) and o-vanillin (H₂MO1, H₂MO2) with ethylenediamine and o-phenylenediamine) in the form of bulk solids and thin films. It is demonstrated that the emission spectra of bulk solid complexes without o-phenylenediamine bridges (ZnSAL1 and ZnMO1) contain additional long-wavelength bands compared to the spectra of corresponding thin films. In the case of films obtained from [ZnSAL1]₂ dimer complexes, the long-wavelength band is dominant. At the same time, the photoluminescence spectra of ZnSAL2 and ZnMO2 complexes with o-phenylenediamine bridges are similar in the case of solid samples and thin films. The electroluminescent properties of organic light-emitting diodes (OLEDs) with the ITO/α-NPD/ZnL/Ca:Al structure are studied. The bathochromic shift of the electroluminescence peaks of OLEDs with respect to the photoluminescence spectra of bulk solid samples and thin films is probably related to the formation of exciplexes at the α-NPD/ZnL interface. The electroluminescence spectra of OLEDs based on [ZnSAL1]₂ show a hypsochromic shift of the emission maximum, which can be caused by a shift of the recombination region into the α-NPD layer.     

Modal liquid crystal wavefront correctors

The results of the development of modal liquid crystal wavefront correctors are reviewed. The modal principle of control is described. Characteristics and examples of application of electrically and optically controlled lenses and multichannel correctors with a tunable response function in different systems are reported.     

Effect of fluoride anions on gramicidin photoinactivation sensitized by sulfonated aluminum phthalocyanines.

Interaction of potent photodynamic agents, sulfonated aluminum phthalocyanines (AlPcSn where n is a number of sulfonic groups), with biological membranes was studied here using model systems: sensitized photoinactivation of gramicidin channels in planar lipid bilayers and adsorption on lipid monolayers. Fluoride anions known to form complexes with aluminum were found to inhibit both the adsorption of aluminum phthalocyanines on lipid monolayers, as measured with a Langmuir trough by surface pressure and surface potential changes, and photodynamic efficacy of the dyes, as studied by gramicidin channel photoinactivation. The similar effects were caused by the alkalinization of the medium. Fluoride anions appeared to be much more effective in the case of AlPcS4 as compared to AlPcS3. The suppression of the photodynamic potency of aluminum phthalocyanines was attributed to desorption of the dyes from lipid bilayers induced by fluoride or hydroxyl ions. With AlPcS4 an enhancement of the dye aggregation leading to a decrease in the sensitizing activity was probably involved in the fluoride effect as revealed by absorption and fluorescence spectral measurements. Capillary electrophoresis was employed to understand the mechanism of the dye desorption. The results of these experiments indicated that the reduction in the membrane affinity was associated with an increase in the negative charge of the dye molecules due to the binding of fluoride or hydroxyl ions.