Laser fluorescence spectroscopy and factor analysis in diagnostics of microbial diseases

Laser-induced fluorescence spectra of blood plasma are studied for patients suffering from microbial diseases. The spectra are measured on an experimental Spektrolyuks laser-fiber multichannel analyzer. A procedure for the statistical processing of the laser-fluorescence data bank is realized based on the method of factor analysis. The experimental results are presented for the learning and test groups. The appropriateness of the hybrid diagnostics in the detection and classification of pathologies with a statistical significance that is acceptable in practical applications is demonstrated.     

Effect of transition metal ions on partial ethane oxidation in an electrochemical system

Transition metal ions (Fe²⁺ and Cu²⁺) have been found to enhance the rate of ethane partial oxidation in a gas-liquid electrochemical reactor under mild conditions (363 K, atmospheric pressure). The effect is discussed in terms of a radical-chain mechanism involving OH radicals.     

Color centres and polymorphism in pure WO3 and mixed (1−x)WO3−y·xReO2 powders

The relationship between structural transformations and colour centres creation is discussed for deeply coloured hydrogen tungsten bronzes and for pure WO₃ powders, acquiring less intense colour after mechanical treatments of variable duration. A comparative study on coloration is made also for mixed compounds (1−x)WO_3−y·xReO₂, where an evidence of a resonance effect for a particular Raman band at 970 cm⁻¹, attributed to the color centres, is observed. Besides, it is found that even moderate milling treatments result in a quite different structural evolution of tungsten trioxide upon cooling. Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999.     

Possible galactic sources of ultrahigh-energy cosmic rays and a strategy for their detection via gravitational lensing

If decays of superheavy relic particles in the galactic halo are responsible for ultrahigh-energy cosmic rays, these particles must be clustered to account for small-scale anisotropy in the AGASA data. We show that the masses of such clusters are large enough for them to gravitationally lens stars and galaxies in the background. We propose a general strategy that can be used to detect such clusters via gravitational lensing, or to rule out the hypothesis of decaying relic particles as the origin of highest energy cosmic rays.     

Investigation of the pore space structure by a scanning electron microscope using the computer program collector

The features and capabilities of the computer program developed for the estimation of petrophysical parameters of oil and gas field rocks are briefly presented. The program is based on the analysis of SEM images of the microstructure of samples.     

Synthesis and antioxidant activity of 7,7,9-trimethyl-6,7-dihydrofuro[3,2-f]quinoline

The method for the synthesis of 7,7,9-trimethyl-6,7-dihydrofuro[3,2-f]quinoline was developed. The parameters characterizing its antioxidant activity, the stoichiometric inhibition factor (f ≈ 3), and the rate constant of the reaction with peroxy radicals (fk ₇ = 2.4 · 10⁵ L mol^?1 s^?1, 60 °C) were determined for the model system of initiated ethylbenzene oxidation. The inhibition stoichiometric factor of furodihydroquinoline is 2, but the colored product formed as a result of its conversion in oxidized hydrocarbons provides the additional inhibition with k ₇ = 6.3 · 10³ L mol^?1 s^?1.     

Observation of double- to single-domain transition on the Eu/Si(1 0 0) surface by LEED and STM

The orientational phase diagram and morphology of the Eu-adsorbed Si(1 0 0) surface miscut by 0.4° have been studied by low-energy electron diffraction and scanning tunneling microscopy. We demonstrate that the original double-domain configuration with single-layer steps on the Si(1 0 0) substrate can be drastically broken at 0.4 monolayer (ML) of Eu. At this coverage, the ordered domain pattern formed by topographically non-equivalent terraces with Eu-induced 2 × 3 and “2 × 1” (so-called “wavy” structure) reconstructions is found, while no orthogonal 3 × 2 and “1 × 2” domains are observed. A model of the single-domain surface is proposed. The origin of the double- to single-domain transition found for the Eu/Si(1 0 0) system is discussed.     

Effect of silane/nano-silica on the mechanical properties of basalt fiber reinforced epoxy composites

The present study explains the role of surface modification of constituent materials on composite material performance. The influence of silane and nano-hybrid coatings on mechanical properties of basalt fibers and composite materials on their base was investigated. Infrared spectroscopy indicated that modification of basalt fiber surface and nano-SiO₂ was successfully applied. The surface modification leads to the significant increase in the tensile strength of basalt fibers compared to the non-coated fibers. The tensile strength of silane-treated fibers was established 23% higher than the non-coated fibers, indicating that silane plays a critical role in the strength retention of basalt fibers. Also it was pointed out that silane coupling agents can be used for the preparation of the nano-hybrid coating. Addition of SiO₂ nanoparticles into the fiber surface was incorporated to enhance the interfacial bonding of basalt fiber reinforced epoxy composite.     

Exactly solvable models of nonstationary turbulence in Bose condensate

In this Letter we study a turbulence decay mechanism in the superfluid liquid. We proceed with developement of master equation approach introduced Copeland, Kibble, Steer and Nemirovskii. We obtain the full rate of reconnection in presence of normal component. We also discuss different random-walk models of vortex filaments. We obtain the expression for the reconnection rate in the nonstationary vortex tangle for these models. The equation for the full number of vortex loops is derived. We also obtain the expression for the relaxation time.