Exciton-polariton transition induced by elastic exciton-exciton collisions in ultrahigh quality AIGaAs alloys

The stationary and time-resolved polariton radiation in ultrahigh quality AIGaAs layers have been studied. It has been found that elastic exciton-exciton collisions lead to the appearance of a low-energy line of polariton radiation. We show that the rate of exciton-to-polariton transitions caused by elastic exciton-exciton collisions is determined not only by the density of the excitonic gas, but also by its temperature; this is in accordance with existing theoretical predictions. The text was submitted by the authors in English.     

Wavy surface nanostructures formed in amorphous silicon films by sputtering with nitrogen ions

Wavy nanostructures are formed on the ion-bombarded surface of single-crystal and amorphous silicon films prepared by various methods. The period and depth of this structure have been determined as functions of the angle of incidence and the energy of nitrogen ions used for the surface sputtering. A comparative analysis of SEM images of the wavy surface nanostructures on various silicon films has been performed using a two-dimensional Fourier transform. The films of amorphous silicon obtained by electron beam deposition and magnetron sputtering techniques are closest to single-crystal silicon films with respect to the wavy surface nanostructure formation.     

A comparison of some approaches to classification problems,and possibilities to construct optimal solutions efficiently

We consider sequential linear (binary) classifiers for the case of many classes along with the linear classifiers based on determining the maximum discriminant function. It is shown that the capabilities of sequential binary classifiers are wider than those of linear classifiers. For the case of linearly non-separable training samples there are considered approaches based on minimizing the margin of misclassification and minimizing empirical risk. It is shown that problem of minimizing the margin of misclassification is polynomially solvable for a certain choice of the norm in the feature space. A refined model of the empirical risk minimization problem and its continuous relaxation are considered, a comparison with the mathematical model of SVM is done. The results of numerical experiments comparing different approaches are discussed.     

Results of Combined Cleaning of the Internal Heating Surfaces of High-Pressure Heaters

The technology, flow diagram, and results of combined cleaning of deposits from the internal heating surfaces (tubes) of high-pressure heaters are describe     

Study of the Composition of a Precipitate Formed from Solutions for the Synthesis of Cathodic Materials Containing Manganese and Citric Acid

Theoretical Foundations of Chemical Engineering - Cathode materials of lithium-ion batteries can be efficiently and quickly obtained by solution combustion synthesis (SCS) from nitrate solutions of...     

Influence of quenching conditions on the mechanical properties and residual stresses of ÉP962 type heat-resistant nickel alloys

VILS. Stupinskii Metallurgical Works. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 10–13, January, 1992.