Selecting the duration of excitation pulses for an electroluminescent thin-film matrix

The factors influencing the optimum selection of the excitation pulse width of thin-film electroluminescent devices is examined. It is shown that to excite an individual cell, a pulse width of 5–7 sec is sufficient, but to excite the matrix, the pulse width is determined by the independence of the conducting layer and the dimensions of the matrix. Formulas are cited for engineering calculations of the required pulse width.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 59–62, December, 1987.     

Fractal nanostructures arising under the ablation of graphite and silicon by millisecond-laser radiation

A mechanism for the formation of fractal nanostructures with micro- and macroscopic sizes under 10-ms laser-pulse irradiation of carbon, silicon, and their mixtures is investigated. The appearance of linear fragments containing nanoclusters is considered based on the diffusion-limited aggregation model with the dipole-dipole interaction. It is shown that the competition between the thermophoretic and gradient forces acting upon particles and their aggregates in a plume determines the area of congestion and the formation of the macroscopical fractal nanostructures.     

On the Local Detectability of the Passage Through the Schwarzschild Horizon

Using the property of the simplest invariant built from the covariant derivatives of the curvature tensor to change sign on the Schwarzschild horizon, and the relativistic quadratic geodesic deviation equation to express the invariant in terms of locally measurable quantities, viz., separation, relative velocity and acceleration of test particles, a scheme is presented which can, in principle, be used by an imaginary observer to detect by local measurements the passage through the event horizon in the Schwarzschild spacetime.     

Magnetic and electric dipole absorption in the dispersed plasma of a laser jet

Experimental results are presented of a study of the magnetic and electric dipole absorption of microwave radiation by a laser plasma which accompanying the evaporation of various metals. An analysis is made of the influence of the finely dispersed fraction on the absorption and it is shown that the model of a percolation cluster provides a good explanation for the entire set of experimental results. Zh. éksp. Teor. Fiz. 116, 1979–1989 (December 1999)