Interaction effects in two-dimensional bianisotropic arrays

Electromagnetic excitation of two-dimensional (2-D) arrays of bianisotropic particles by plane waves is considered. Arrays (grids) are assumed to be infinite and the particles to be small compared to the wavelength, so that the dipole approximation is possible. The electromagnetic interaction between all the particles changes the properties of these particles (in particular, chiral and omega particles are studied). The analytical model under consideration allows one to express the electric and magnetic moments induced in each particle through the incident wave fields in terms of collective polarizability dyadics (CPDs). The proposed method to evaluate these dyadics combines numerical and analytical parts. The results of the calculations of the induced electric and magnetic moments by plane waves are presented for a planar arrangement of omega particles     

The ways to improve the quality of welding due to preliminary elimination of residual magnetization

The contemporary methods for improving the quality of welding of gas pipelines are considered, and new methods for decreasing magnetic blowout are proposed.     

Sub-Millimeter-Wave Spectroscopy of the Ar.H+3 and Ar.D+3 Ionic Complexes

The human papillomavirus type 11 (HPV-11) E7 protein can modulate host cell functions and is required for papilloma formation, but little is known concerning the regulation of its expression. This study was designed to determine whether the viral upstream regulatory region controlled expression from the E7 promoter and whether cis sequences differentially regulated E6 and E7 expression in laryngeal mucosal keratinocytes, the natural target cells for this virus. Reporter constructs were designed to study expression of the luciferase gene from the HPV-11 E7 promoter in its natural position downstream of a functional E6 promoter. E7 expression, like E6 expression, required upstream regulatory sequences. However, E7 expression was less sensitive to repression by viral E2 protein and to mutation of the Spl binding site adjacent to the E2 binding site. Moreover, there was differential sensitivity of the two promoters to mutation of the E6 TATA box, with E7 expression more affected than E6 expression. These findings show that, in the normal host cells for this virus, the E6 and E7 promoters can be independently regulated by the cis regulatory region adjacent to the E6 promoter.     

Quantum informatics with single atoms

Current status of the research on the use of single neutral atoms, captured in optical traps, as a quantum computer’s qubits, is briefly reviewed. The specifics of qubits based on cold atoms and t quantum logical operations via dipole interaction by short-time laser excitation in a Rydberg state are discussed. The latest experimental results of the observation of dipole interaction between two Rydberg atoms and of atoms’ entangled states in a ground state are given.     

Material testing by plotting total deformation curves

The paper deals with the theoretical and experimental aspects of the study of the behavior of materials at the stage of supercritical deformation or work softening, consideration of which is important for the assessment of the durability of structures. The study results show the theoretical confirmation of the effect of the specimen configuration on the possibility of plotting the descending portions of deformation curves. It is shown that the equilibrium supercritical deformation of a material is possible if the stiffness of the loading system is sufficient. This is confirmed by the results of the uniaxial tension tests with unloading at various stages of elastoplastic and supercritical deformation. The method for interpreting experimental data obtained for the specimens of various dimensions under conditions of deformation localization are considered.     

Laser surfacing of nickel-based composite war-resisting coatings reinforced with tungsten carbide

Investigations were carried out into the phase and structural state of the gradient coating produced by laser surfacing using tungsten carbide powders in a cobalt coating and a nickel alloy. The results show that the structure contains the WC carbide with the particles of the carbide forming spherical agglomerates, a nickel solid solution, alloyed with iron and cobalt, Me₂W₆ intermetallic phase, where Me = Fe, Cr and also CrO₂ oxide. It is shown that the layers after reheating are characterized by the more extensive dissolution of the carbide and agglomerates and the formation of chromium-containing inclusions. The distribution of the elements and microhardness values in the cross section of the deposited coating was determined.     

A device for removing metal from the weld pool when studying the shape of the weld pool

The dimensions and shape of a weld pool have a strong effect on both the technological and service parameters of welded joints. To investigate the shape and dimensions of a weld pool, a device for removing molten metal from the pool cavity for different materials and thickness of the welded specimens was designed and constructed. Investigation of the shape of the pool in laser welding showed special features of the pool in comparison with arc welding     

Simple and Accurate Analytical Model of Planar Grids and High-Impedance Surfaces Comprising Metal Strips or Patches

Simple analytical formulas are introduced for the grid impedance of electrically dense arrays of square patches and for the surface impedance of high-impedance surfaces based on the dense arrays of metal strips or square patches over ground planes. Emphasis is on the oblique-incidence excitation. The approach is based on the known analytical models for strip grids combined with the approximate Babinet principle for planar grids located at a dielectric interface. Analytical expressions for the surface impedance and reflection coefficient resulting from our analysis are thoroughly verified by full-wave simulations and compared with available data in open literature for particular cases. The results can be used in the design of various antennas and microwave or millimeter wave devices which use artificial impedance surfaces and artificial magnetic conductors (reflect-array antennas, tunable phase shifters, etc.), as well as for the derivation of accurate higher-order impedance boundary conditions for artificial (high-) impedance surfaces. As an example, the propagation properties of surface waves along the high-impedance surfaces are studied.