Separation of kerogen from green river oil shale

The complex analysis of the chemical composition and technological properties of oil shale from the Green River formation was carried out. The technical characteristics and granulometric composition of test samples and the element compositions of the mineral and organic matters of shale rocks were determined. The structure of organomineral aggregates formed upon the crushing of shale rocks was studied by electron microscopy. Based on the experimental data, a procedure was developed for the separation of kerogen from the oil shale by physicochemical processing.     

Selection of parameters of position-sensitive photodetectors for measurement of lateral displacements of laser beams

Conclusions 1. Theoretical relationships have been obtained for the design and practical application of devices using position-sensitive photodetectors. 2. It has been found that for maximum sensitivity it is sufficient that the photodetector size is twice as large as the spot radius (Ã 2). It has been proved that maximum nonlinearity of the positional response is observed for small reduced dimensions of the photodetector (Ã) and is of the order of ( being the reduced radial displacement of the spot); the minimum nonlinearity occurs for Ã>2 where it does not exceed . 4. The threshold displacement sensitivity has been evaluated as being of the order of several hundredths of a micrometer (for a spot radius equal to 1 cm).Translated from Izmeritel'naya Tekhnika, No. 12, pp. 35–38, December, 1977.     

Vion chemisorptive fibres — materials for protecting the environment from harmful substances

Conclusions Technology has been developed for the preparation of VION chemisorptive fibre containing chemically active groups, which are able to sorb substances of various chemical natures. The chemisorptive and mechanical properties of VION fibre do not change over the course of many sorption-regeneration cycles.As experience in operating industrial plants in a number of branch plants has shown, it is advisable to use chemisorptive fibrous materials as a filtering material for protection of the environment; these ensure a high rate and completeness of removal of harmful discharges as a result of their highly developed surface.Translated from Khimicheskie Volokna, No. 3, pp. 32–37, May–June, 1989.     

Long-distance fiber-optic quantum key distribution using superconducting detectors

This paper presents the results of experimental studies on quantum key distribution in optical fiber using superconducting detectors. Key generation was obtained on an experimental setup based on a self-compensation optical circuit with an optical fiber length of 101.1 km. It was first shown that photon polarization encoding can be used for quantum key distribution in optical fiber over a distance in excess of 300 km.     

An efficient electron-beam-pumped semiconductor laser for the green spectral range based on II–VI multilayer nanostructures

Emission characteristics of an electron-beam-pumped Cd(Zn)Se/ZnMgSSe semiconductor laser are studied. The laser’s active region consists of a set of ten equidistant ZnSe quantum wells containing fractional-monolayer CdSe quantum-dot inserts and a waveguide formed by a short-period superlattice with the net thickness of ～0.65 μm. Lasing occurs at room temperature at a wavelength of 542 nm. Pulsed power as high as 12 W per cavity face and an unprecedentedly high efficiency of ～8.5% are attained for the electron-beam energy of 23 keV.     

Radiation-conduction heat transfer in fibrous heat-resistant insulation under thermal effect

The conjugate diffusion model of radiation transfer and the approximation of radiant thermal conductivity are used to investigate the radiation-conduction heat transfer in a flat layer of fibrous heat-resistant insulation under the effect of fire. The results of calculation of the characteristics of unsteady-state heat transfer and of the duration of heat resistance of the substrate demonstrate the accuracy of the approximation of radiant thermal conductivity which is good for practical applications. The fireproof efficiency of fibrous quartz heat insulation is investigated. The calculation results demonstrate that the application of this insulation provides for high limits of fire resistance of metal structures.     

Dental enamel hypoplasia in children with combined congenital and hereditary defects in the development of the CNS and the locomotor system (infantile cerebral palsy, spinal cord hernias and myopathies)]

The incidence of hypoplasia in children with congenital and hereditary developmental defects of the central nervous system and the locomotor system is high (44.5 +/- 3.5%), much higher than the incidence of hypoplasia in children without neurological disorders (2.0 +/- 2.0%). This is explained by exposure of the fetus and newborn to numerous intensive factors complicating the biological anamnesis because of profound disturbances of the metabolic processes and largely responsible for the underlying neurological disease and defects of hard dental tissues presenting as hypoplasia of the enamel.     

Adsorption of haematoporphyrins on the planar bilayer membrane

Adsorption of haematoporphyrin derivatives with different hydrophobicities of peripheral groups on a planar bilayer lipid membrane (BLM) was studied in the dark and upon illumination by the visible light. Haematoporphyrin molecules were shown to adsorb on the BLM as anions. The adsorption changed the boundary potential at the membrane/water interface, in particular, it altered the potential in the diffuse part of the double layer outside the membrane and increased an additional unscreenable potential drop inside it. Illumination decreased the value of the negative potential drop due probably to the appearance of a positive charge in the haematoporphyrin macrocycle. The adsorption of haematoporphyrins affected the BLM conductivity induced by different ionophores, which can be explained by changes in membrane structure. Haematoporphyrin derivatives with higher hydrophobicities adsorbed deeper inside the membrane, caused greater changes in its structure and displayed a stronger photodynamic effect.     

Possibilities of using surgical laser in the treatment of chronic tonsillitis

A novel technique of surgical treatment of chronic tonsillitis is presented. It implies the use of Ne-YAG laser in contract regimen. Good results were obtained in experiments on the exposure of distal tonsils to intralacunar laser radiation.