Features of the integration of graphenes in microelectronic technology

Techniques have been developed for forming integrated graphene structures on a silicon wafer surface by mechanical and chemical splitting and chemical vapor deposition. The imperfection of the fabricated structures has been investigated by atomic force microscopy and X-ray diffraction. For the aerosol technique of deposition of mechanically spit graphite, the regularity has been revealed in the reduction of the graphene sheet size with increasing pressure. The correlation of the topographic defects of graphene material and the structural defects observed in X-ray diffraction patterns is demonstrated.     

Size effect in galvanomagnetic phenomena in bismuth films doped with tellurium

The results of experimental investigation of galvanomagnetic phenomena in single-crystalline and block films of tellurium-doped bismuth in the temperature range of 77–300 K and in the film-thickness range of 0.1–1 μm are presented. It is shown that the charge-carrier concentration in the investigated films is independent of thickness, the charge carriers are scattered at phonons, the film surface, structural defects, and crystallite boundaries. The values and ratio of the listed contributions to the restriction of charge-carrier mobility depend on the tellurium content, film thickness, and also their single-crystalline or block state.     

Distortions of the gap impedance of the active cavity of a broadband multiple-beam klystron coupled with the filter system

Distortion of the gap impedance of the active cavity of a broadband multiple-beam klystron is investigated. A technique for averaging of the gap impedance in beam transport channels on the basis of calculation of the coordinates of the center of gravity of the real part of gap impedance function obtained by means of numerical simulation is proposed.     

Experimental investigations and numerical simulation of the electron flow shaped by Grigor’ev-Shesterkin matrix carbon field-emission cells

The results of the investigations of the electron flow in Grigor’ev-Shesterkin field-emission cathode cells intended for use in microwave tubes are presented. It is shown that it is possible to develop electron-optical systems (EOSs) with field-emission cathode matrices for O-type microwave tubes whose beam emittance is similar to the that of the EOSs with grids and hot cathodes.     

Thermodynamic properties of the R-415A refrigerant in the vapor phase and on the condensation line

The speed of sound in the R-415A refrigerant vapor and its density and pressure on the condensation line were measured by the ultrasonic interferometer and constant-volume piezometer methods within a range of temperatures from 293 to 373 K and pressures from 0.04 to 0.5–2.45 MPa. The temperature, pressure, density and speed of sound measurement errors were ±20 mK, ±4 kPa, and ±(0.1–0.2)%, respectively. The temperature dependence of the ideal-gas heat capacity was calculated on the basis of the obtained data. The obtained results were compared with the properties calculated by the REFPROP software.     

Research of the interaction of an electron flow with a coupled-cavity chain slow-wave structure at the passband boundary with the help of the intermodulation components

An experimental approach is proposed for research of the interaction beyond the passband of a coupled-cavity chain slow-wave structure, and the characteristics of a traveling-wave tube are experimentally analyzed.     

Prospects of wind energy sector development in Serbia with relevant regulatory framework overview

The growth of the renewable energy sector in the world in the first decade of the twenty-first century was rapid. Wind energy sector was one of the fastest growing renewable energy technologies. In this paper, authors have tried to review the current state of wind power utilization in Serbia as one of the most penetrating RES technologies in the world. The brief overview of electric power sector in Serbia was given in order to describe the environment for emerging wind energy sector development. Sufficient wind energy resources were identified in several regions of the country. Current energy policy in Serbia was reviewed in terms of the regulations that have to be followed in order to meet the requirements for RES power plants, i.e. wind power plant construction. In subsequent section short reviews of wind energy projects which are in their initial phases are provided. The wind energy sector in Serbia is emerging despite the difficulties faced by the investors, regulatory bodies and other shareholders, in the course of the past several years. There is an urgent need of a broader transfer of specific knowledge and technologies related to wind farms and wind turbines in order to speed up the current wind energy sector development.