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.     

Necessary and sufficient conditions for existence of exponential dichotomy of impulsive equations

Necessary and sufficient conditions for the existence of an exponential dichotomy of impulsive differential equations in a Hilbert space are found.     

Theoretical temperature-electric field phase diagram for deuterated thiourea SC(ND2)2

A theoretical temperature-electric field phase diagram is constructed for thiourea SC(ND₂)₂ using a phenomenological approach based on the representation of the thermodynamic potentials for all phases. The theoretical diagram is compared with the experimental diagram. Fiz. Tverd. Tela (St. Petersburg) 39, 1282–1286 (July 1997)