Modelling the Sliding Behaviour of Tribofilms Forming During Automotive Braking: Impact of Loading Parameters and Property Range of Constituents

The impact of pressure, sliding velocity and property variation of constituents on the sliding behaviour of a model tribofilm was studied with the method of movable cellular automata (MCA). Whereas a clear pressure dependency of the coefficient of friction (COF) was always observed and could be correlated with the structure formation in terms of varying thickness of a mechanically mixed layer, the impact of the other parameters was either negligible or rather weak. Only if a brittle-to-ductile transition of the oxide-based tribofilm was assumed, a significant decrease in the COF level was predicted. Temperature-dependent property changes can be neglected during MCA modelling, unless this transition takes place. For magnetite-based tribofilms, the transition temperature is beyond 800°C, i.e. a temperature leading to fading effects during braking anyway. Thus, it could be concluded that, except for very severe braking conditions, sliding simulations with the MCA method yield meaningful results without considering temperature-dependent mechanical properties.     

Effect of postgrowth techniques on the characteristics of triple-junction InGaP/Ga(In)As/Ge solar cells

The photoelectric characteristics of triple-junction InGaP/Ga(In)As/Ge solar cells are studied in relation to the method used to form the photocell chip. It is shown that the application of a postgrowth technique developed in the study for separating a nanoheterostructure into chips in a single process makes it possible to improve the quality of passivation of the chip edges, which diminishes the surface leakage currents and makes larger the yield of devices with improved characteristics.     

Vision of Genesis of Presentation of Hi-Tech Project during Competitive Selection

The presentation of high-tech projects (including research and development projects) submitted to funding competitions is considered. Two-stage development of such presentations is proposed. The first step is to ensure that the selected set of characteristics is representative and may be estimated with sufficient precision. The next step is to introduce a mathematically formalized business model of the project, permitting its financial evaluation. This model must adequately and transparently identify the financial potential of the economic cluster that will implement the submitted project. Embodied in software, this model must support stress testing of the high-technology project and optimization of its characteristics.     

Calculation of the Thermoelectric Properties of n- and p-Type Lead Telluride Using a Three-Band Model of the Electron Energy Spectrum

In this paper, we study theoretically the thermoelectric properties of n- and p-type PbTe in the wide temperature interval of 300–900 K. A three-band model of the PbTe electron energy spectrum is used in these calculations. The full set of the relevant kinetic characteristics is calculated including the electrical and thermal conductivities, the Seebeck coefficient, and the thermoelectric figure-of-merit. The calculated thermoelectric quantities are in good agreement with the available experimental data.     

Dynamic chaos in the microwave range generated in SiGe-based autooscillatory structure

A chaotic microwave autooscillatory structure has been designed, implemented on a monolithic IC manufactured by 0.25-μm silicon-germanium technology, and studied. The experiments with the IC showed the possibility of generating stable chaotic oscillations in the 3–8-GHz range.