Optical properties of a liquid-crystal cell subjected to a binary action of periodic shear and compression

A mechanooptical effect is described that appears in a liquid-crystal cell that contains a nematic liquid-crystal layer with an initial homeotropic alignment and is subjected to the binary action of periodic shear and compression. The change in the optical properties of the cell (increase in its transparency) is shown to be controlled by effects that are linear and nonlinear in a shear amplitude, and their relative contributions at high and low frequencies are analyzed.     

Channeling of Neutrons in the Potential Well of a Planar Waveguide

The channeling of neutrons in a three-layer planar waveguide with a neutron-optical potential well is studied. Neutrons incident on a sample surface, which propagate in a middle layer and escape from the waveguide end in the form of a narrow divergent beam, are detected. The decay parameter of a neutron wave inside the waveguide is measured as a function of the potential well depth. Experimental results are compared with a theory.     

Improving image quality in reflection confocal microscopy involving gold nanoparticles and osmotically active immersion liquids

We consider the possibility of using gold nanoparticles to improve the image contrast of biotissue structures in reflection confocal laser microscopy. We present the results of experimental studies using gold nanospheres with a diameter of 60 nm compared to osmotically active immersion contrast agents based on glycerol.     

KINETICS OF DYNAMIC HOLOGRAM RECORDING IN POLYMER FILMS WITH IMMOBILIZED BACTERIORHODOPSIN

Abstract
Polymer films with immobilized photosensitive membrane protein, bacteriorhodopsin (BR), were prepared and investigated. A sensitive holographic interferometer with phase modulated optical beams was used for investigation of kinetics of dynamic hologram recording in BR polymer films. It was found that phase hologram formation consisted of two quasi-exponential stages demonstrating existence of a diffusive process in obtained films. It was shown that the kinetics of a phase hologram recording by high intensity beams do not correlate with the exponential law. The applicability of BR polymer films as reversible photorefractive materials for dynamic holography and real-time interferometry was discussed.     

Kinetics of electron transfer between VIV and VV in heteropolyanions

Conclusions A study has been made of the kinetics and equilibrium of the reaction of electron transfer between V^IV and V^V in 12-series heteropolyanions and in the reaction of dissociation of V^IV from the HPA.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp, 2469–2472, November, 1984The authors wish to express their appreciation to V. N. Parmon for valuable comments.     

Study of the OZI selection rule in hadronic processes

In the experiments with LEPTON-F and SPHINX spectrometers the pion-induced charged exchange reactions π- + p → ? + n and π- + p → ω + n at Pπ-=32.5 GeV, as well as proton-induced diffractive reactions p + N → [p?] + N and p + N → [pω] + N at E _p =70 GeV were studied. The comparison of the cross-sections for ? and ω-production in these reactions is used for testing the OZI selection rule in hadronic processes. It has been demonstrated that in pion reactions the ratio of the yields of ? and ω-mesons R(?/ω) = (3 ± 1) · 10^?3 is in a good agreement with naive quark model prediction based on the mixing in vector meson nonet and on the OZI rule (R(?/ω)ozi = tg ²Δθ _V ? 4 · 10^?3). At the same time in proton reactions the effective ratio of ? and ω yields is ～ (4 ÷ 7) · 10^-2, i.e. a strong violation of the OZI rule is observed in proton-nucleon interactions. This violation can be in favor of possible existence of some exotic ss? component in the quark structure of protons.     

Acidity function of concentrated solutions of 12-tungstophosphoric acid

Conclusions The authors have measured the Hammett acidity functions H₀ of concentrated solutions of H₃PW₁₂O₄₀ in water, aqueous dioxane, and acetic acid. In these solvents the acidity of H₃PW₁₂O₄₀ is higher than those of sulfuric and hydrochloric acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 492–493, March, 1982.     

Heteropolyacids as catalysts for synthesis of methyl tert-butyl ether

The influence of the composition and structure of heteropolyacids (HPA) on their catalytic activity in the liquid phase synthesis of methyl tert-butyl ether (MTBE) at 42 °C has been studied. The activity of HPA is compared with that of other acid catalysts. The most active are HPA's of the Dawson structure, then come HPA's of the Keggin and Dexter-Silverton structures. HPA salts have low activity in the synthesis of MTBE.

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