Reaction of 3-Alkoxy-7-methylenebicyclo[3.3.1]non-2-ene with N-Halosuccinimides

Russian Journal of General Chemistry -     

Account of Thermal Flow Through Metal-Semimetal BiSb Contact Boundary for Determination of EHF Detector Volt-Watt Sensitivity

Bismuth, antimony and its alloys are the typical representatives of a class of semimetals, which electric conductance is lower in 10²-10³ times, than of usual well conducting an electrical current metals. The alloys bismuth with antimony have semi-conductor properties in wide area of compositions at temperatures below 77 °K. The semimetals are rather perspective materials from the point of view of their probable application in various devices [1,2,3].In present time the semimetal alloys BiSb have wide application in thermoelectric generators and refrigerators. In work [3] the opportunity of use of semimetals BiSb with percentage content of Bi and Sb from 8 % up to 25 % was shown as high-sensitivity and of small inertion indicators of the mm range radiation where thermoelectric effect is used. The principle of action of such indicators is based on occurrence of temperature gradient in a semimetal crystal BiSb that has two contacts of the various area with flowing electrical current. Basic element of such device is the dot contact metal - semimetal. One of the main characteristics is volt-watt sensitivity of metal-semimetal BiSb contact which calculating is shown in present work.     

Nonlinear magneto-optical diffraction by two-dimensional magnetic superstructures

Nonlinear (at the second-harmonic frequency of the incident light) optical reflection by two-dimensional magnetic superstructures is theoretically studied. A square lattice of magnetic dots and a hexagonal lattice of magnetic bubbles (cylindrical magnetic domains) are considered. Because the periods of these structures are comparable with the wavelengths of the fundamental and the second-harmonic radiation, it would be possible to observe diffraction at the second-harmonic frequency. A polarization analysis of nonlinearly diffracted radiation is performed and the numbers of observable diffraction orders for the above structures are estimated. Received: 10 January 2002 / Published online: 11 June 2002     

Mechanism of detachment of particles from the surface of high-temperature superconducting targets absorbing laser pulses

A cluster mechanism is considered for the detachment of particles when the surface of a high-temperature superconducting target absorbs laser pulses. By proposing a fractal nature for the surface, one can model it as an assembly of a large number of nonlinear oscillators (clusters). Utilizing the method of sudden perturbations, a calculation was made of the probability of dissociation of these oscillators, i.e., of the detachment of clusters from the surface. The calculated probability decreases rapidly as the power density of the laser radiation is reduced to some limiting value. This is in agreement with experiments. State Institute of Sensory Microelectronics. Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 73–77, June, 1997.     

Mutual coupling of elements in finite microstrip antennas

The mutual coupling of the radiating elements in microstrip antennas is studied using a rigorous electrodynamic approach in which the field singularities at the radiator edges are taken into account with analytic accuracy. A spectral method is employed in combination with a method of semi-inversion by extraction of the Green-function singularity. The degree of interaction of the elements of microstrip structures at the fundamental and higher current harmonicsis determined, and the applicability of various approximations is assessed.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, No. 8, pp. 688–701, August, 1992.     

Two-dimensional Numerical Simulation of the Beam-Plasma-Discharge

A two-dimensional self consistent model of the Beam-Plasma-Discharge (BPD) has been developed to calculate the discharge ignition of a bandlike electron beam in a discharge chamber. The discharge was considered in Argon with an initial concentration of 10¹⁴ cm^?3. The model allows calculation of the time evolution of perpendicular profiles of electron density, temperature and the potential.     

Kinetics and mechanism of oxidation of indigo carmine by hypohalites

Kinetics of oxidation of indigo carmine (IC) by sodium hypohalites, NaOX (X ? Cl or Br), in alkaline buffer of pH 9–11 has been studied spectrophotometrically at λ = 610 nm. The experimental rate law obtained is ?d[IC]/dt = k[OX^?][IC][OH^?]^x where x <1. Variation of ionic strength or dielectric constant of the medium had no effect on the reaction rate while the addition of halide ions slightly retarded the rate. A most plausible mechanism proposed on the basis of experimental results involves the formation of isatin sulphonate which undergoes further oxidation to anthranilate. Activation parameters have been evaluated.     

The evolution of the viscoelastic retardation spectrum during the development of an epoxy resin network

The evolution of the viscoelastic behavior of an epoxy resin at various stages of curing has been followed with the changes in the retardation spectrum. The creep J(t) and recoverable creep compliance J_r(t) curves of the neat epoxy resin Epon l00lF (Shell) were determined at temperatures between 30 and 77°C. The viscosity decreased over 8 orders of magnitude as the temperature was increased. Specimens with eight stages of network development were prepared by reacting all of the epoxy resin's oxirane rings with amine hydrogens from varying ratios of a monofunctional amine (methyl aniline) and a tetrafunctional amine 4,4′-diamino diphenyl sulfone (DDS). Preparations in which 25, 35, and 40% DDS were used did not result in a molecular network, so they were viscoelastic liquids. With 45% DDS, the product had a nascent network and was judged to be just beyond the point of incipient gelation. The remaining preparations from 0.50, 0.60, 0.70, and 1.0 DDS yielded tighter less compliant molecular networks. The creep and recoverable compliance curves were measured over a range of temperatures above the glass transition temperature, T_g. They were reduced to T_g, and retardation spectra L(ln τ) were calculated.     

Some remarks on operator ranges

Translated from Teoriya Funktsii, Funktsional'nyi Analiz i Ikh Prilozheniya, No. 53, pp. 69–70, 1990.