Properties and structural state of the surface layer in a zirconium alloy modified by a pulsed electron beam and saturated by hydrogen

A pulsed action of an electron beam on a Zr-1% Nb zirconium alloy is studied. Alloy samples are irradiated by three 50-μs pulses at an energy density of 15–25 J/cm², a power of (3–6) × 10⁴ W/cm², a current density of 10–50 A/cm², and an electron energy of 18 keV. This method of processing is found to modify the surface layer of the alloy without changing the structure-phase state of its volume. This surface modification increases the hydrogen saturation resistance of the alloy.     

Sequences of composition operators in spaces of functions of bounded Φ-variation

The main results of the paper are contained in Theorems 1 and 2. Theorem 1 presents necessary and sufficient conditions for a sequence of functions h _n : 〈c, d〉 → 〈a, b〉, n = 1, 2, ..., to have bounded sequences of Ψ-variations {V _Ψ (〈c, d〉; f ? h _n )} _n=1 ^∞ evaluated for the compositions of an arbitrary function f: 〈a, b〉 → ? with finite Φ-variation and the functions h _n . In Theorem 2, the same is done for a sequence of functions h _n : ? → ?, n = 1, 2, ..., and the sequence of Ψ-variations {V _Ψ(〈a, b〉; h _n ? f)} _n=1 ^∞ .     

Luminescence centers in silicate and germanate glasses activated by bismuth

Concentration series of silicate and germanate glasses activated by bismuth are studied. It is shown that luminescence in the IR region is controlled by several active centers related to bismuth. Based on a comparison of spectroscopic characteristics of the studied glasses with the data previously obtained for chloride glass, the observed centers were identified as Bi⁺, Bi ₂ ⁴⁺ , and Bi ₅ ³⁺ in germanate glass and Bi⁺, Bi ₂ ⁴⁺ in silicate glass.     

Non-Contradictory Aggregation of Strict Order Relations

We study the problem of collective choice. The profile of individual preferences of experts is defined by relations of strict order. A non-contradictory aggregate preference relation is based on the weighted majority graph that characterizes the degree of superiority of one alternative over another. The aggregate relation also defines a strict order and satisfies requirements to group decisions, namely, the monotony, the preservation of the Pareto relation, the minimality of the distance to expert preferences.     

Magnetized SPR sensor for enhanced functionality

It is known that a magnetic field changes the RI and the SPR angle of specific analytes. We have applied an external magnetic field to a surface plasmon resonance (SPR) sensor to exploit this phenomenon. A gold film is used for excitation of SPR in the sensor with a Kretschmann configuration. According to the concentration of 4-type analyte, we observed unique changes of the SPR angle due to the magnetic field, providing better classification of material type than a conventional SPR sensor.     

A relativistic core-envelope model on pseudospheroidal space-time

A core-envelope model for superdense matter distribution with the feature- core consisting of anisotropic fluid distribution and envelope with isotropic fluid distribution is reported on the background of pseudospheroidal space-time. The physical plausibility of the model is examined analytically and numerically.     

Estimating the energy performance of an insulator with regard to the relaxation time distribution

The energy relationships in the macroscopic electrodynamics of an insulator are analyzed with regard to the polarization relaxation time distribution. Expressions for the discharge power and discharge energy flux densities in an insulator are derived for an electric field exponentially depending on time. The performance of polyethylene terephthalate in capacitive energy storage systems is estimated in terms of energy.     

Limiting absorbing belt for a quasiperiodically driven mapping of the shift of intervals

For a discontinuous dynamical system with discrete time on a two-dimensional cylinder generated by a quasiperiodically driven mapping of the shift of intervals with overlapping, we prove the existence and uniqueness of a limiting semiinvariant absorbing belt whose width lies within the same limits as the width of overlapping. In the case of overlapping of constant width, this belt is invariant, and the dynamics inside the belt is equivalent to a skew shift on a two-dimensional torus.     

The spin state of manganese atoms in Sr2MnSbO6 complex oxides

The magnetic susceptibility of Sr₂MnSbO₆ solid solutions in a Sr₂AlSbO₆ diamagnetic diluent is investigated. Variation in the magnetic characteristics with temperature and the solution concentration indicates the coexistence of two spin states of manganese atoms: low-spin and high-spin. The possibility of spin transitions is due to temperature-dependent local distortions in the crystal structure of the solutions.     

Scattering of acoustic waves by macroscopically inhomogeneous poroelastic tubes

Wave propagation in macroscopically inhomogeneous porous materials has received much attention in recent years. For planar configurations, the wave equation, derived from the alternative formulation of Biot's theory of 1962, was reduced and solved recently: first in the case of rigid frame inhomogeneous porous materials and then in the case of inhomogeneous poroelastic materials in the framework of Biot's theory. This paper focuses on the solution of the full wave equation in cylindrical coordinates for poroelastic tubes in which the acoustic and elastic properties of the poroelastic tube vary in the radial direction. The reflection coefficient is obtained numerically using the state vector (or the so-called Stroh) formalism and Peano series. This coefficient can then be used to straightforwardly calculate the scattered field. To validate the method of resolution, results obtained by the present method are compared to those calculated by the classical transfer matrix method in the case of a two-layer poroelastic tube. As an example, a long bone excited in the sagittal plane is considered. Finally, a discussion is given of ultrasonic time domain scattered field for various inhomogeneity profiles, which could lead to the prospect of long bone characterization.