Enhancement of Nonlinear Optical Effects in Porous Composite Plasmonic Structures

A method for formation of bulk plasmonic structures based on porous quartz with silver nanoparticles in pores has been proposed and implemented. The spectroscopy of their optical and nonlinear optical properties has been performed by methods of second harmonic generation and two-photon absorption. A significant increase in the nonlinear absorption coefficient has been detected in the plasmon resonance region. The enhancement of the second optical harmonic has been observed with the shift by tens of nanometers from the plasmon resonance position toward the long-wavelength region.     

New ways to increase the depth of crude oil refining

Experimental data on thermal oxidative degradation of petroleum tar and mazut (distillation residue) are presented. Experiments were performed in a pilot installation with a continuous 1.5-L reactor at temperatures of 430–460°С and pressures of 2–6 atm with feeding air into the reactor in an amount of 30–80 L kg^–1. Under these conditions, the yield of light fractions considerably increases (to 36% for tar and to 57% for mazut) as compared to thermal cracking. As in the case of thermal cracking, the cracking residue can be used as boiler fuel or asphalt. Based on the yield of hydrocarbon fractions obtained at different process parameters, the general scheme of thermal oxidative transformations of the feed was suggested, and a mathematical model describing all the experimental data obtained was constructed.     

Heuristic Topological Decomposition Algorithm for Optimal Energy-Resource-Efficient Routing of Complex Process Pipeline Systems

A heuristic topological decomposition algorithm for optimal energy-resource-efficient routing of complex process pipeline systems was developed. The algorithm is distinguished by using an automated procedure for constructing a topological model of a hydraulic circuit as a hydraulic structural graph, a modified algorithm for finding the shortest spanning tree of the initial structural graph, and a set of heuristic rules. The developed algorithm enables one to determine the optimal energy-resource-efficient route with minimum reduced cost.     

Measurements of work function of pristine and CuI doped carbon nanotubes

We report the results on measurements of the work function of carbon nanotubes and carbon-nanotube-based materials including pristine multi-walled and single-walled carbon nanotubes as well as single-walled carbon nanotubes intercalated by CuI with the Kelvin probe technique. We found the work function value 4.97–4.98 eV for pristine carbon nanotubes, while carbon nanotubes infilled with CuI demonstrate the work function value decreased by more than 0.1 eV (4.86–4.96 eV).     

Conversions of 1-arylamino-3-phenyloxindoles

Acetylation of 1-arylamino-3-phenyloxindoles by acetic anhydride in the presence of an acidic catalyst (TsOH) gives N-acetyl derivatives; alkylation by methyl iodide in the presence of sodium ethoxide gives C₍₃₎- and N-dimethyl derivatives. Reduction by lithium aluminum hydride gives 1-arylamino-3-phenylindolines, which form the corresponding indoles when they are oxidized by chloranil.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1362–1365, October, 1984.     

Influence of growth conditions on microstructure and properties of GaSe crystals

GaSe crystals have been grown from melt. There are several reasons why it is difficult to meet ideal demands for nonlinear optic material, GaSe single crystal. First, these crystals have a tendency towards lamination because of great difference in a and c crystal lattice parameters and very weak Vander der Waals forces in c direction. Next, there is a great difference in saturation vapor pressure of the components, which can cause nonstoichiometry of a melt-grown crystal composition. Another obstacle in the growth of perfect GaSe crystals is dendrite formation caused by instability of the growth front. To overcome this obstacle we used Bridgman technique and have found the temperature and pressure conditions, and growth velocity which provide growth of perfect bulk single crystals of about 100 mm in length and 20 mm in diameter. Sharp Laue patterns and a rocking curve confirm perfect structure of the grown crystals. Electron-probe X-ray microanalysis shows stoichiometric composition of GaSe crystals and X-ray phase analysis reveals presence of single-phased hexagonal structure.     

Efficient Integration of Single-Photon Emitters in Thin InSe Films into Resonance Silicon Waveguides

A concept of the optimal design of a silicon waveguide based on optically coupled Mie-resonant nanoantennas for efficient inputting of light from point emitters associated with excitons localized at defects in a thin InSe film is proposed. Numerical calculations demonstrate that the efficiency of coupling between a dipole emitter and a resonant silicon waveguide is four orders of magnitude greater than that for a conventional ridge waveguide.

     

Approximate Mathematical Model of Heat Exchange in a Complex Thermal Engineering System of Several Product Pipelines Carrying a Motionless Isothermal Product within a Single Insulating Jacket

An approximate mathematical model was developed to describe the heat exchange in a complex thermal engineering system of several parallel product pipelines carrying an motionless isothermal product within a single insulating jacket. The model is distinguished by using a simplified mathematical model of the steady-state heat conduction on a circle (motionless product) and in an annulus (product pipeline wall) under the Robin boundary conditions using various “approximating” effective heat-transfer coefficients in different parts of the boundary of a heated product pipeline carrying the isothermal product with the air space and the insulation.