A quantum steganography protocol based on <Emphasis Type="Italic">W</Emphasis> class entangled states

The condition of ɛ-security based on the quantum relative entropy is presented and a protocol that uses decoherence-free states is considered for the quantum steganography system.     

Study of Active Microwave Compressors Excited by Magnicon Radiation at a Frequency of 11.4 GHz

We present the results of a study of single-channel and two-channel compressors of microwave pulses, operated at a frequency of 11.4 GHz, in which a high-Q factor storing resonator and a novel plasma switch are used. In the single-channel compressor excited by magnicon radiation at a frequency of 11.4 GHz, 24-MW pulses have been obtained for a compression ratio equal to 8. In the two-channel compressor, coherent composition of pulses with the use of a 3-dB directional coupler has been demonstrated. Compressed pulses with powers of 9 to 11 MW and durations of 50 to 60 ns have been obtained at the incident-power level 1–1.5 MW, which corresponded to the compression ratio k = 8–9.3.     

Synthesis and magnetic properties of the exchange-coupled SrFe10.7Al1.3O19/Co composite

The magnetic composite SrFe_10.7A_l1.3O₁₉/Co was synthesized by ethylene glycol reduction of cobalt ions on the surface of hexaferrite particles dispersed in the solvent. The resulting material contained magnetically hard submicron hexaferrite particles covered by soft magnetic cobalt nanoparticles. The composite demonstrated the exchange-coupling effect between hard and soft magnetic phases.     

Transmission of quantum correlations of light into atoms

The interaction between two broadband modes of a parametric source of light and two atoms located at different positions has been considered. As follows from the obtained Bell inequalities for light and atoms, quantum correlations of modes, which are caused by the nonlocality of the state of the source, are completely transmitted into atoms. The system under consideration can be used as a quantum channel where information is encoded in nonorthogonal states by modulating the intensity of a pump wave. The channel capacity has been calculated, which is determined by the Helstrom limit.     

Effect of the polarity of functional groups (-H, -OH, and -COOH) on the structure of a solvent near single-wall carbon nanopipes

The effect of the functionalization of carbon nanopipes on the structure of a phase separation nanopipe solvent at 300 K was performed using molecular dynamics. Radial distribution functions, ranged radial distribution functions, self-diffusion coefficients, coordination numbers, and the number of hydrogen bonds for the investigated systems were obtained. The influence of the polarity of functional groups on the structure of water near nanopipes was established.     

Homogenization of the equations of the Cosserat theory of elasticity of inhomogeneous bodies

The paper deals with the homogenization of a boundary value problem for an inhomogeneous body with Cosserat properties, which is referred to as the original problem. The homogenization process is understood as a method for representing the solution of the original problem in terms of the solution of precisely the same problem for a body with homogeneous properties. The problem for a body with homogeneous properties is called the accompanying problem, and the body itself, the accompanying homogeneous body. As a rule, a constructive homogenization procedure includes the following three stages: at the first stage, the properties of the inhomogeneous body are used to find the properties of the accompanying homogeneous body (efficient properties); at the second stage, the boundary value problem is solved for the accompanying body; at the third stage, the solution of the accompanying problem is used to find the solution of the original problem. This approach was implemented in mechanics of composite materials constructed of numerous representative elements. A significant contribution to the development of mechanics of composites is due to Rabotnov [1–3] and his students. Recently, the homogenization method has been widely used to solve problems for composites of regular structure by expanding the solution of the original problem in a power series in a small geometric parameter equal to the ratio of the characteristic dimension of the periodicity cell to the characteristic dimension of the entire body. The papers by Bakhvalov [4–6] and Pobedrya [7] were the first in the field. At present, there are numerous monographs partially or completely dealing with the method of a small geometric parameter [8–14]. Isolated problems for inhomogeneous bodies with nonperiodic dependence of their properties on the coordinates were considered by many authors. Most of such papers published before 1973 are collected in two vast bibliographic indices [15, 16]. General methods were considered, and many specific problems of the theory of elasticity of continuously inhomogeneous bodies were solved in Lomakin’s papers and his monograph [17]. The theory of torsion of inhomogeneous anisotropic rods was considered in [18]. In 1991, in his Doctoral dissertation, one of the authors of this paper proposed a version of the homogenization method based on an integral formula representing the solution of the original static problem of inhomogeneous elasticity via the solution of the accompanying problem [19, 20]. An integral formula for the dynamic problem of elasticity was published somewhat later [21]. This integral formula was used to develop a constructive method for the homogenization of the dynamic problem of inhomogeneous elasticity, which can be used in the case of both periodic and nonperiodic inhomogeneity of the properties [22]. The integral formula in the case of the Cosserat theory of elasticity was published in [23]. The present paper briefly presents constructive methods for homogenizing the problems of the Cosserat theory of elasticity based on the integral formula.     

On nonlinear effects in condensation models with continuous and discrete descriptions of nucleation

A set of nonlinear equations for the evolution of the condensate fraction is suggested. The diffusion approximation to the Zel’dovich equation is shown to be fundamentally inapplicable for describing nonlinear effects. A diffusion equation with the applicability domain free of limitations due to supersaturation smallness is derived.     

Nanometric diamond delta doping with boron

Diamond is desired for active semiconducting device because of it high carrier mobility, high voltage breakdown resistance, and high thermal diffusivity. Exploiting diamond as a semiconductor is hampered by the lack of shallow dopants to create sufficient electronic carriers at room temperature. In this work, nanometer thick, heavily boron doped epitaxial diamond ‘delta doped’ layers have been grown on ultra smooth diamond surfaces which demonstrate p type conduction with enhanced Hall mobilities of up to 120 cm²/Vs and sheet carrier concentrations to 6 × 10¹³ cm^–2, thus enabling a new class of active diamond electronic devices. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)