Free subsemigroups in topological semigroups

We prove that a complete metrizable topological semigroup with identity that contains a free dense subsemigroup and no commutative neighbourhoods of identity is almost free. We apply this result to the full transformation semigroup of countable degree and the semigroup of automaton transformations over finite alphabet.     

Potentiometric Electronic Tongue for Taste Assessment of Ibuprofen Based Pharmaceuticals

The flavor aspect of pharmaceutical formulations is very important in terms of their acceptability for the patient. This work is aimed at using of a novel promising type of electronic tongue (ET), consisting of a potentiometric sensor array, for the discrimination and assessment the taste of commercial pharmaceuticals based on ibuprofen (Ibuflam 4 %). The sensor array was formed by six ion‐selective membranes (ISMs) based on both specific and non‐specific active components. Analysis of potentiometric signal outputs including statistical data processing utilizing the principal component analysis (PCA) method allowed evaluating the role of individual active components of the ISMs in the sense of taste control of the pharmaceutical preparation Ibuflam 4 % before and after flavoring. The sensing array can be used to identify differences in flavor within individual batches from the same producer, since ISMs provide a different response to all components present in the analyzed pharmaceutical. The ET contains ISMs which are able to recognize the bitter taste in the framework of the batches of ibuprofen based pharmaceuticals. To recognize bitter taste, it was essential to include ISMs, providing a response to a particular type of taste, namely, specific and non‐specific ISMs. The experimental findings show that taste‐sensing potentiometric sensor system can be a good alternative to the human panel and is able to detect the slight changes in taste.     

Enhancement of Piezoelectric and Dielectric Properties and Macroscopic Relaxation of Charge and Field Response in 0–3 Ceramic-Pore Composites: Theory and Experiment

In this work, we have theoretically and experimentally described the dielectric and piezoelectric properties of ceramic-based lead zirconate–titanate composites that have a 0–3 bond. Based on the proposed model, the frequency dependences of the dielectric and piezoelectric response have been determined theoretically and experimentally. The influence of the Maxwell–Wagner relaxation and the effective parameter approximation on the physical properties of disordered objects of statistical mixture have been studied. The distribution functions of the times of intercomponent relaxation in the piezoceramic–pores composite system and the concentration dependences of the effective field responses have been determined. The theoretical and experimental results obtained have been compared.     

Formation of adsorbate structures induced by external electric field in plasma-condensate systems

We present a new model of plasma-condensate system, by taking into account an anisotropy of transference reactions of adatoms between neighbor layers of multi-layer system, caused by the strength of the electric field near substrate. We discuss an influence of the strength of the electric field onto first-order phase transitions and conditions for adsorbate patterning in plasma-condensate systems. It is shown that separated pyramidal-like multi-layer adsorbate islands can be formed in the plasma-condensate system if the strength of the electric field near substrate becomes larger tan the critical value, which depends on the interaction energy of adsorbate and adsorption coefficient.     

Multiplicity distribution in proton-proton and proton-antiproton collisions at high energies

Multiplicity distributions of secondary hadrons produced in p $ \bar p $ \bar p and collisions are very different. There are three types of inelastic processes in p $ \bar p $ \bar p scattering. The first one is the production of a shower of secondary hadrons in gluon string decay. The second one is the shower produced from the decay of two quark strings, and the third one is the shower produced from the decay of three quark strings. At the same time, there are just two types of inelastic processes for pp scattering: the shower from the gluon string and the shower from two quark strings. The multiplicity distribution and the average multiplicity of charged hadrons for an energy of 14 TeV are predicted.     

A theory of the inverse magnetoelectric effect in layered magnetostrictive–piezoelectric structures

A theory of the inverse magnetoelectric effect in layered structures has been presented. The theory is based on solving the equations of elastodynamics and electrostatics separately for the magnetostrictive and piezoelectric phases, taking into account the conditions at the interface between the phases. Expressions for the coefficient of inverse magnetoelectric conversion through the parameters characterizing the magnetostrictive and piezoelectric phases have been obtained. Theoretical dependences of the inverse magnetoelectric conversion coefficient on the frequency of the alternating-current electric field for the three-layer PZT–Ni–PZT structure and the two-layer terfenol-D–PZT structure have been calculated. The results of the calculations are in good agreement with the experimental data.     

Localized nonlinear waves in systems with time- and space-modulated nonlinearities

Using similarity transformations we construct explicit nontrivial solutions of nonlinear Schr?dinger equations with potentials and nonlinearities depending both on time and on the spatial coordinates. We present the general theory and use it to calculate explicitly nontrivial solutions such as periodic (breathers), resonant, or quasiperiodically oscillating solitons. Some implications to the field of matter waves are also discussed.     

Scattering of charged particles by atoms

A closed variant of the Born approximation for calculating differential scattering cross sections in ion-atom collisions is developed. An expression in terms of the matrix elements J _ij with respect to the single-electron states of the atom is found for the matrix element describing the target atom in the formula for the differential cross section. The matrix elements J _ij are averaged over the relative orientation of the momentum transferred in the collision and the symmetry axis of the electronic orbitals of the target atom, using the single-electron Rutaan-Hartree-Fock wave functions. The algebraic representation of the matrix elements J _ij makes it possible to perform calculations for atoms with any value of Z. The model developed is used to calculate the cross sections σ_Σ and characteristic scattering angles θ_c for the process of electron loss by H^? ions with energy E = 0.1–100 MeV in targets consisting of atoms with Z = 2–54. It is shown that σ_Σ ∝ E ^?1 and θ_c ∝ E ^?1/2 for all Z, and for fixed E the behavior of σ_Σ(Z) and θ_c(Z) is determined by the order of filling of the electronic shells of the target atoms (the ionization potential). The computational results are analyzed and compared with the experimental data and the results of other calculations.     

Angular characteristics of processes of electron detachment from negative ions and hydrogen atoms in gases

The results of experimental measurement of spatial-angular distributions of hydrogen particles (H⁻, H⁰, H⁺) obtained in scattering of a collimated ribbon beam of H⁻ ions and H⁰(1s) atoms in He, Ar, Kr, Xe, H₂, O₂, and CO₂ gas targets for certain values of energy in the range from 0.6 to 15 MeV are reported. The experimental setup and the measurement procedure with an angular resolution of 5×10⁻⁶ rad are described. The angular characteristics of measured distributions, i.e., full width at half maximum and standard deviation, were determined. It is shown that the shape of distribution for a beam of hydrogen atoms produced by neutralization of H⁻ ions in a gas target varies with the type and thickness of the target, and the angular spread is smallest for the H₂ target. The variations in the shape of distribution are due to the contribution of scattering processes without changing the charge of particles.