In the framework of the Landau-Lifshitz model the new types of solitons in the semi-infinite ferromagnet are analytically described under the boundary conditions, corresponding to the partial pinning of spins at the boundary of the sample. The problem is successively solved for isotropic, easy-axis, easy-plane and two-axis ferromagnets. Comparative analysis of interaction of solitons with the surface of the sample is performed.

The modification of the inverse scattering problem is proposed to investigate solitons and dispersive waves in the framework of the Landau-Lifshitz model for semi-infinite ferromagnet with an <> anisotropy under the mixed boundary conditions, corresponding to different degrees of spin pinning on the edge of the sample. New types of solitons are obtained and their elastic reflection from the edge of the sample is analyzed. Spectral expansions of the integrals of motion for solitons and waves are found. Additional integrals of motion are established that guarantee true boundary conditions for solitons, when they interact with the edge of the sample.

We propose a special variant of the inverse scattering transform method to construct and analyze soliton excitations in a semi-infinite sample of an easy-axis ferromagnet in the case of a partial pinning of spins at its surface. We consider the limit cases of free edge spins and spins that are fully pinned at the sample boundary. We find frequency and modulation characteristics of solitons localized near the sample surface. In the case of different degrees of edge spin pinning, we study changes in the cores of moving solitons as a result of their elastic reflection from the sample boundary. We obtain integrals of motion that control the dynamics of magnetic solitons in a semi-infinite sample.

We study theoretically the nonlinear interactions of vector breathers propagating on an unstable wavefield background. As a model, we use the two‐component extension of the one‐dimensional focusing nonlinear Schrödinger equation—the Manakov system. With the dressing method, we generate the multibreather solutions to the Manakov model. As shown previously in [D. Kraus, G. Biondini, and G. Kovačič, Nonlinearity 28(9), 3101, (2015)], the class of vector breathers is presented by three fundamental types I, II, and III. Their interactions produce a broad family of the two‐component (polarized) nonlinear wave patterns. First, we demonstrate that the type I and the types II and III correspond to two different branches of the dispersion law of the Manakov system in the presence of the unstable background. Then, we investigate the key interaction scenarios, including collisions of standing and moving breathers and resonance breather transformations. Analysis of the two‐breather solution allows us to derive general formulas describing phase and space shifts acquired by breathers in mutual collisions. The found expressions enable us to describe the asymptotic states of the breather interactions and interpret the resonance fusion and decay of breathers as a limiting case of infinite space shift in the case of merging breather eigenvalues. Finally, we demonstrate that only type I breathers participate in the development of modulation instability from small‐amplitude perturbations withing the superregular scenario, while the breathers of types II and III, belonging to the stable branch of the dispersion law, are not involved in this process.

Glasses in the yP(2)O(5)-xLa(2)O(3)-(100-y-x)V2O5 system have been obtained in the composition ranges of y = 5, 10, and 15 mol% and x =1, 2, 3, 4, and 5 mol% using the melt quenching method. The concentration dependences of characteristic temperatures and density are found to pass through the maximum and minimum, respectively. In all studied composition ranges, the introduction of 1 mol% La2O3 leads to a slight increase in conductivity; after that, the conductivity gradually decreases. Such behavior is explained by the results of non-constant field molecular dynamics simulation in terms of the mean coordination number of the V...V pair. The conductivity value at a temperature of 50 ?& nbsp;reaches 3.2.10(-4) S.cm(-1) for the composition x = 1 and y = 5.

Triple-conducting oxides are considered to be nextgeneration materials for renewable and green energy as parts of fuel cells, electrolyzers, and membrane reactors. The electrochemical properties of any material are tightly correlated with its structural features. Because all ionic transport in oxides is related to point defects, it is crucial to understand their location and surroundings. In this work, we use total X-ray and neutron scattering to investigate how the introduction of Co into a proton-conducting oxide La0.9Sr0.1Sc1-xCoxO3-delta influences the local structural disorder and location of protons. Using non-constant force field molecular dynamics, we investigate the proton trapping effect and point out a way of avoiding it. Under an applied voltage, we observe proton diffusion anisotropy, which significantly improves the proton conductivity of oxide membranes. We show that the introduction of cobalt into a proton-conducting oxide can increase the number of incorporated protons compared to previous expectations. This, coupled with the absence of proton trapping and proton conductivity anisotropy, means that the potential of A3+B3+O3 perovskites could be much greater than considered so far. Our computational results will improve our understanding of the features of proton transport by updating the model of proton conductivity in triple-conducting oxides.

Soliton states in a semi-infinite ferromagnetic film with partially pinned spins at its boundary are found and analyzed within the focusing nonlinear Schrödinger equation (NLSE). It is shown that solitons are divided into two classes. The first class includes magnetization oscillations with discrete frequencies localized near the film edge. The second class contains moving particle-like objects whose cores are strongly deformed at the film boundary; these objects are elastically reflected from this boundary, thus recovering the shape of solitons typical for a unbounded sample. A series of conservation laws for a wave field is obtained that ensures the localization of soliton oscillations near the boundary of the sample and the elastic reflection of moving solitons from this boundary. It is shown that a change in the phase of the internal precession of a soliton during reflection depends on the character of spin pinning at the edge of the sample.

By means of the dressing technique, we build multipole solutions of the focusing Manakov system under a constant background. These solutions become degenerate when the poles of the dressing function merge. We find that with a special choice of the integration constants, such solutions describe the fusion or decay of the pulsing solitons-breathers-and their wave numbers and frequencies satisfy the typical resonance condition. We investigate the different cases of such resonance interactions.

azTotMD 2.0 is a parallel molecular dynamics program which includes both conventional algorithms and a novel "radiative" thermostat and a temperature-dependent force field. The radiative thermostat is based on the black-body radiation law and acts like virtual adsorption and radiation of photons. The thermostat algorithm has complexity of O(N), it can accelerate and decelerate atoms and this action over time leads to a Maxwell-like distribution of velocities. The temperature-dependent pair potential includes atomic radii, which are functions of the thermal excitation of atoms. The combination of the radiative thermostat and the potential allows to reproduce many phenomena such as phase transitions, thermal expansion, defect formation, surface tension, vapor saturation, glass formation and devitrification.

Amorphous glasses of the composition xMgO–yP2O5– (100 – x – y)V2O5 with x = 1–5 and y = 5, 10, and 15 mol % are obtained by the melt quenching technique. The amorphous state of samples is confirmed by XRD analysis. The density of glasses is determined by pycnometry. The introduction of 1 mol % magnesium oxide into the glass composition sharply decreases its density, the further increase in the magnesia concentration is accompanied by the graduate increase in density. The conductivity of glasses is measured by two methods: on direct current and by impedance spectroscopy. Comparing these results makes it possible to infer the electronic nature of conduction. The temperature dependence of glass conductivity is linear in the Arrhenius coordinates. For the compositions with y = 10 and 15, the dependence of conductivity on the magnesia content (x) passes through maximum x = 1 mol %. The glass model is build by the self-assembly procedure with the use of the non-constant force field molecular dynamics method. The analysis of configurations reveals that the concentration of 4-cooordinated environment of vanadium passes through a small maximum when 1 mol % MgO is present in the section xMgO–10P2O5–(90 – x)V2O5, which can be considered as an explanation of the conductivity maximum.

El presente estudio pretende aportar nuevas metodologías para la

The structure and properties of glasses in the 30Na2O–xV2O5–(70 – x)B2O3 system for x varying from 30 to 47.5 mol % were studied using experimental approaches and non-constant force field molecular dynamics. The replacement of boron oxide by vanadium oxide was found to decrease the glass transition temperature and the thermal stability of glasses. According to the results of infrared spectroscopy, over the whole range of concentrations studied, there is no significant changes in the type of structural groups that form the glass network. This conclusion is supported by the absence of abnormal changes in the concentration dependences of characteristic temperatures and conductivity, which monotonically increases with increasing V2O5 content. The procedure of glass self-assembly from a melt in the non-constant force field molecular dynamic simulation was used for the first time to obtain the structural model. The interatomic distances between the vanadium cations and the trajectories of ion motion in the system were determined. The conductivity was found to be due to electron transfer.

Quasi-binary phosphate-vanadate glasses have been studied by both IR spectroscopy and a novel method of molecular dynamics with a non-constant force field. This method is used for the self-assembly of structural models of glasses. The obtained models and the glass network structure are analyzed quantitatively using element distribution by the number of R–O–R bonds (R is phosphorous or vanadium) and 4-, 6-, and 8-membered cycles. The bends on the concentration dependences of atoms distribution in the second coordination sphere agree well with changing the shape of IR spectra. Based on the cycle analysis, the formation of cycles is shown to be more characteristic for vanadate fragments that can form 4-membered cycles, which, according to Zachariasen’s rule, negatively affects glass-forming ability.

We study vector solitons propagating on an unstable constant background (vector breathers) theoretically in the framework of the focusing two-component one-dimensional nonlinear Schrödinger equation. Based on the simplified inverse scattering transform technique called the dressing method, we find the exact solutions describing resonance interactions of the vector breathers. The resonance represents a three-breather process, i.e., a fusion of two breathers into one or decay of one breather into two, such that the characteristic wave vectors and frequencies of the breathers satisfy resonance conditions.

The structure and properties of glasses in the 30Na 2 O– x V 2 O 5 –(70 – x )B 2 O 3 system for x varying from 30 to 47.5 mol % were studied using experimental approaches and non-constant force field molecular dynamics. The replacement of boron oxide by vanadium oxide was found to decrease the glass transition temperature and the thermal stability of glasses. According to the results of infrared spectroscopy, over the whole range of concentrations studied, there is no significant changes in the type of structural groups that form the glass network. This conclusion is supported by the absence of abnormal changes in the concentration dependences of characteristic temperatures and conductivity, which monotonically increases with increasing V 2 O 5 content. The procedure of glass self-assembly from a melt in the non-constant force field molecular dynamic simulation was used for the first time to obtain the structural model. The interatomic distances between the vanadium cations and the trajectories of ion motion in the system were determined. The conductivity was found to be due to electron transfer.

Glasses in xV(2)O(5)-(100-x)P2O5 system within x range from 35 to 95 mol% are obtained by a melt-quenching method and characterized by X-ray powder diffraction, atomic emission spectroscopy and red-ox titration. The dependences of density and molar volume of glasses on V2O5 concentration are linear up to 90 mol% of vanadium oxide and can be expressed via formulas: rho = 2.64 + 0.36.xV(2)O(5) g cm(-1) and V-mol/ = 54.17 + 6.36.xV(2)O(5) cm(3) mol(-)(1). The electronic conductivity of glasses is measured by both impedance spectroscopy and direct current methods. The glass composition of 95V(2)O(5)center dot 5P(2)O(5) shows the highest electrical conductivity value of similar to 1.0 x 10(-4) S cm(-1) at 50 degrees C. The concentration dependence of the conductivity is described at a qualitative level with non-constant force field molecular dynamics.

A detailed analysis of solutions to the Landau–Lifshitz equation describing solitons in a physically selected domain structure of a biaxial ferromagnet is presented. The structure and properties of new types of solitons that are strongly bound to the domain structure are investigated. Soliton behavior near the boundaries of their region of existence is considered. A comparative analysis of soliton cores in the domain structures of easy-axis and biaxial ferromagnets is performed, and their connection with solitons against a uniformly magnetized background is established.

Glasses in 30Li(2)O-(70-x)B2O3-xV(2)O(5) system (x = 30, 40, 47.5 mol%) are obtained by melt quenching method. Their structure has been studied by a set of experimental and simulation methods such as nuclear magnetic resonances, X-ray diffraction, and molecular dynamics. The coordination numbers of lithium and boron ions are determined from NMR data and confirmed by XRD analysis; the obtained data are compared with the simulation results. Based on the experimental and simulation results, the model of the glass network is constructed. According to the experimental data and simulation results, boron coordination in the glasses is 3 and 4, and vanadium coordination is equal to 5 and 6.