Том 59, № 2 (2016)

In this article we have synthesized multilayer contact systems Ti/Ag and Ti/Mo/Ag with nanostructured silver films using two vacuum methods, namely the method of electron-beam evaporation and HF magnetron sputtering. Using the data of atomic force microscopy, X-ray diffraction and mass spectroscopy of the secondary neutrals in the paper we have investigated the influence of the application method and of the annealing conditions on the grain formation processes in silver thin films and mass transfer between the metal layers of the contact system. The decrease of surface resistivity of the developed contacts and, respectively, the increase of short-circuit current of the heterojunction silicon solar cells have been determined.

Physical processes and self-heating factors of in a power submicron field-effect heterotransistor have been considered. Mathematical models were proposed and the electrothermal analysis of heterotransistor parameters and characteristics was performed. The impact of thermal processes on parameters of the circuit model and the output frequency characteristics of submicron heterotransistor was shown on the basis of analysis of temperature fields. The relationship of the transistor thermal resistance as a function of its geometry and thermophysical parameters has been established.

In this paper we present the method for determination of the specific auscultatory diagnostic signs in patients with chronic obstructive pulmonary disease (COPD), which is based upon the utilization of the polyspectral analysis and the calculation of higher order statistics. The main stages of the method are the calculation and construction of the bicoherence function of the lung sound signal in order to find its maximal value. The visual and numerical estimations of the obtained maximum allow us to conclude the presence or absence in this lung’s audio signal of the artifact, which indicates the pathology. For more accurate results one needs to determine asymmetry coefficient and to perform the estimation of bifrequency corresponding to the maximal value of the bicoherence coefficient. The calculation of skewness and kurtosis coefficients of cross-correlation functions of lung sound signals, which were recorded simultaneously in four channels, allows us to reduce the sensitivity of the method to noise components. Therefore, by analyzing all proposed calculated characteristics and parameters one can conclude the presence or absence of the pathology in this audio signal.