Minimax matrix correction of inconsistent systems of linear algebraic equations with block matrices of coefficients

The problem of correction of matrices (extended matrices) of inconsistent systems of linear algebraic equations with block structure and with the cost function of minimax type is considered. These problems are reduced to a constrained optimization problem, which, in turn, is reduced to a series of linear programming problems. All problems of matrix correction are illustrated by numerical examples.     

Development of nano indium tin oxide (ITO) grains by alkaline hydrolysis of In(III) and Sn(IV) salts

Indium tin oxide (ITO) nano powders of different compositions (In: Sn = 90: 10, 70: 30 and 50: 50) were prepared by heat treatment (300-450°C) of mixed hydroxides of In(III) and Sn(IV). The hydroxides were obtained by the reaction of aq. NH₃ with mixed aq. solutions of In(NO₃)₃ and SnCl₄. FTIR and TG/DTA studies revealed that powders existed as In(OH)₃H₂O—SnO₃H₂H₂O in the solid state and then they transformed to In₂O₃—SnO₂ via some metastable intermediates after 300°C. Cubic phase of In₂O₃ was identified by XRD for the oxides up to 30% of Sn. Particle size measurements of the solid dispersed in acetone and SEM study for microstructure showed that the oxides were in the nano range (55-75 nm) whereas the size range determined from Debye-Scherrer equation were 11–24 nm.     

A computational study of LP-based heuristic algorithms for two-dimensional guillotine cutting stock problems

In this paper we develop and compare several heuristic methods for solving the general two-dimensional cutting stock problem. We follow the Gilmore-Gomory column generation scheme in which at each iteration a new cutting pattern is obtained as the solution of a subproblem on one stock sheet. For solving this subproblem, in addition to classical dynamic programming, we have developed three heuristic procedures of increasing complexity, based on GRASP and Tabu Search techniques, producing solutions differing in quality and in time requirements. In order to obtain integer solutions from the fractional solutions of the Gilmore-Gomory process, we compare three rounding procedures, rounding up, truncated branch and bound and the solution of a residual problem. We have coded and tested all the combinations of algorithms and rounding procedures. The computational results obtained on a set of randomly generated test problems show their relative efficiency and allow the potential user to choose from among them, according to the available computing time. Rceived: January 9, 2001 / Accepted: December 10, 2001     

The effect of charge relaxation on the electromagnetic radiation of an oscillating charged viscous drop

A dispersion equation for the capillary oscillations of a charged drop of incompressible liquid possessing a finite electric conductivity is derived with an allowance for the energy lost as a result of the electromagnetic wave emission. The magnitude of the electromagnetic radiation losses of the oscillating drop linearly increases with the electric conductivity and the surface mobility of charge carriers.     

Fabrication of MOD-derived YBCO films on [001]LaAlO/sub 3/ and their application to /spl lambda//4 CPW SIR BPFs

Chemically derived epitaxial thin films of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) are fabricated on [001]LaAlO/sub 3/ substrates by the metalorganic-deposition (MOD) process, which has advantages of high quality, nonvacuum, low-cost, and large-scale production of high-T/sub c/ superconducting films. The MOD-derived YBCO films have a sharp transition at the critical temperature (90.4 K) and a high-quality film with a surface resistance of 0.13 m/spl Omega/ (30 K, 9.98 GHz) is obtained. As a microwave application, simple and compact bandpass filters (BPFs) using /spl lambda//4 coplanar-waveguide. stepped-impedance resonators are demonstrated on the YBCO films. A two-stage Chebyshev BPF of center frequency of 5.731 GHz, bandwidth of 135 MHz, and insertion loss of 0.29 dB with little input power dependency in a power range less than 10 dBm is realized on the film.     

Morphological compression of grayscale images of text

A new method for compression of grayscale images containing a small number of graphical elements is proposed. The method is characterized by high compression ratios, small losses, and good readability of the processed images. It is based on morphological methods of image analysis and could be used to store images of documents produced by fax machines, scanners, etc. Igor I. Falomkin. Born 1979. Graduated from the Faculty of Physics, Moscow State University, in 2001. Scientific interests: image analysis and recognition, analysis and interpretation of experimental data.     

Investigation of the Possibility of Using UNK Superconducting Dipole Magnets for Producing Rapid-Cycling Magnetic Fields

The superconducting dipoles developed as part of the UNK project have reached a magnetic field 6 T at a rate of up to 0.8 T/sec. Experimental data are presented on the conditioning, rate dependences, and dynamic losses for magnets with two types of superconducting cable (zebra and oxide). Possible ways to decrease the heat release in a dipole operating in rapid-cycling magnetic fields are examined. The results of an analysis of heat release and temperature conditions are presented for a dipole with a winding made of improved current-carrying components.     

Thermal expansion of gray tin

Translated from Izmeritel'naya Tekhnika, No. 7, pp. 40–41, July, 1989.