Vol 18, No 2 (2015)

In the prresent paper we have considered the influence of the initial atomic coherence on entanglement dynamics of two qubits one of which is trapped in a lossless cavity and interacts with single-mode thermal field, and the other one can be spatially moved freely outside the cavity. We have shown that the atomic coherence in the model under the consideration can be used for effective control on the degree of the entanglement of qubits.

We assumed that in our earlier papers that the interaction between some metal atoms and their intercalation inside the nanotube is possible. These facts suggest us that the boron-carbon nanotube may be the new material, which is as well as pure carbon nanotube become the basis of the nanoelelctronic devices. For this reason the continuation of metal adsorption mechanism studying is important. The way of intercalation (doping) of alkaline metal inside the BC3-nanotube and modeling of the regular external adsorption is suggested. Results of researches showed that doping of boron-carbon nanotubes is possible and the electron density is distributed near nanotube surface atoms. Regular external adsorption of the alkaline metal atoms causes decreasing of the energy gap compared with the pure boron-carbon nanotube. So, we can obtain that intercalation of metal atom inside the BC

The calculation of surface conductivity of graphene monolayer determined from the Kubo formulа taking into account in the model the intraband and interband conductivities is performed depending on the frequency. The influence of chemical potential on the surface conductivity of grapheme changed by the external electric field is researched at the teraherz frequency range.

The difference between the spectrum of forced oscillations of disk dielectric resonators (when distributed coupling with dielectric waveguide is used) and eigen oscillations of such resonator is considered. The dependence of the amplitude-frequency response of the resonator, excited on the whispering-gallery modes, upon the value of distributed resonator-waveguide coupling and the role of inter-type interaction at purely internal excitation of extraneous mode is investigated.

On the basis of the numerical solution of the integral and differential equations with existential operators for equivalent axial distributions of currents and charges the analysis of secondary radiation of radio impulses by a mirror and asymmetric element in the form of the opened ring with perpendicular its planes pieces at edges of a gap is carried out. Influence of analytical properties of the bending-around and time-and-frequency parameters of the irradiating signals on the power chart of dispersion of object is investigated.

The estimations of potential coordinate measurement accuracy in multi-static forward scattering radar with mobile positions are obtained. The two analytical methods of coordinate measurement are considered. The mathematical modeling results are presented.

By using current-voltage characteristic and electro-photo luminescence measurements, the efficiency of spin electronic injection was investigated in the Co/Al_2 O_3 tunnel barrier/GaAs based structure, where spin current was generated by electric injection from FM to GaAs through the tunnel barrier. The investigations were performed on the devices with different tunnel barrier thickness of Al_2 O_3 surmounted by a thin Co ferromagnetic layer. The increase of the effectiveness of the electrical injection was identified by an increase in the intensity of electroluminescence; thereby we can define the optimal thickness of the layer of Al_2 O_3 as a tunnel and as a diffusion barrier. Also, manipulation of the tunneling barrier thickness leads to control of emission threshold of diode structures and sensitive diode. We also demonstrated the dependence between the tunneling barrier thickness and Schottky barrier height and the resistance of diode structure.