Antropo-technological methods of training of physical actions with application of heuristics methods and cogitation of metaphorisation

Problems of training to biomechanics in educational sports institutes are considered. Opportunities of transition of educational technologies «from school of knowledge to school of thinking» are shown. The general scientifc sight of students is reached by knowledge of mainstreams in modern theories of training to impellent actions. It is necessary to provide to students space for the mental and productive actions basing concrete methodical and practical positions. The student should very well «read movements to build actions»

Multi-field continuum theory for medium with microscopic rotations

We derive the multi-field, micropolar-type continuum theory for the two-dimensional model of crystal having finite-size particles. Continuum theories are usually valid for waves with wavelength much larger than the size of primitive cell of crystal. By comparison of the dispersion relations, it is demonstrated that in contrast to the single-field continuum theory constructed in our previous paper the multi-field generalization is valid not only for long but also for short waves. We show that the multi-field model can be used to describe spatially localized short- and long wavelength distortions. Short-wave external fields of forces and torques can be also naturally taken into account by the multi-field continuum theory.Comment: 14 pages, 4 figures, submitted to International Journal of Solids and Structure

On a Class of Spatial Discretizations of Equations of the Nonlinear Schrodinger Type

We demonstrate the systematic derivation of a class of discretizations of nonlinear Schr{\"o}dinger (NLS) equations for general polynomial nonlinearity whose stationary solutions can be found from a reduced two-point algebraic condition. We then focus on the cubic problem and illustrate how our class of models compares with the well-known discretizations such as the standard discrete NLS equation, or the integrable variant thereof. We also discuss the conservation laws of the derived generalizations of the cubic case, such as the lattice momentum or mass and the connection with their corresponding continuum siblings.Comment: Submitted for publication in a journal on October 14, 200

Discrete Nonlinear Schrodinger Equations Free of the Peierls-Nabarro Potential

We derive a class of discrete nonlinear Schr{\"o}dinger (DNLS) equations for general polynomial nonlinearity whose stationary solutions can be found from a reduced two-point algebraic problem. It is demonstrated that the derived class of discretizations contains subclasses conserving classical norm or a modified norm and classical momentum. These equations are interesting from the physical standpoint since they support stationary discrete solitons free of the Peierls-Nabarro potential. As a consequence, even in highly-discrete regimes, solitons are not trapped by the lattice and they can be accelerated by even weak external fields. Focusing on the cubic nonlinearity we then consider a small perturbation around stationary soliton solutions and, solving corresponding eigenvalue problem, we (i) demonstrate that solitons are stable; (ii) show that they have two additional zero-frequency modes responsible for their effective translational invariance; (iii) derive semi-analytical solutions for discrete solitons moving at slow speed. To highlight the unusual properties of solitons in the new discrete models we compare them with that of the classical DNLS equation giving several numerical examples.Comment: Misprints noticed in the journal publication are corrected [in Eq. (1) and Eq. (34)

Two-soliton collisions in a near-integrable lattice system

We examine collisions between identical solitons in a weakly perturbed Ablowitz-Ladik (AL) model, augmented by either onsite cubic nonlinearity (which corresponds to the Salerno model, and may be realized as an array of strongly overlapping nonlinear optical waveguides), or a quintic perturbation, or both. Complex dependences of the outcomes of the collisions on the initial phase difference between the solitons and location of the collision point are observed. Large changes of amplitudes and velocities of the colliding solitons are generated by weak perturbations, showing that the elasticity of soliton collisions in the AL model is fragile (for instance, the Salerno's perturbation with the relative strength of 0.08 can give rise to a change of the solitons' amplitudes by a factor exceeding 2). Exact and approximate conservation laws in the perturbed system are examined, with a conclusion that the small perturbations very weakly affect the norm and energy conservation, but completely destroy the conservation of the lattice momentum, which is explained by the absence of the translational symmetry in generic nonintegrable lattice models. Data collected for a very large number of collisions correlate with this conclusion. Asymmetry of the collisions (which is explained by the dependence on the location of the central point of the collision relative to the lattice, and on the phase difference between the solitons) is investigated too, showing that the nonintegrability-induced effects grow almost linearly with the perturbation strength. Different perturbations (cubic and quintic ones) produce virtually identical collision-induced effects, which makes it possible to compensate them, thus finding a special perturbed system with almost elastic soliton collisions.Comment: Phys. Rev. E, in pres

SPECTRAL CHARACTERISTICS STUDY OF PHASE-SHIFTED FIBER BRAGG GRATINGS UNDER PRESSURE APPLIED PERPENDICULAR TO FIBER AXIS

Subject of Research.The paper presents the study of effect that occurs when pressure is applied to the phase-shifted fiber Bragg gratings perpendicular to the fiber axis. Method. Fiber Bragg gratings inscription was performed using Talbot interferometer, and the introduction of a phase shift – by means of the electrical discharge of an arc fusion splicer. The excimer laser system was used as a radiation source. The change in the reflection spectra at different pressures on the optical fiber is measured. Main Results. Fiber Bragg gratings with a phase shift are obtained by the procedure that excludes the use of high-precision instruments during the phase-shift introduction step. Experiment results are given showing up the distance dependence between the local minima in the reflection spectrum of fiber Bragg grating with a phase shift on the applied mass arising as a result of the induced birefringence. It is shown that the change in spectral characteristics is related to the birefringence effect owing to stresses inside the fiber. As a result, the second local minimum appears in reflectance band. Practical Relevance. Research results can be used in creation of a sensing element of a fiber optic pressure sensor. This study demonstrates the application possibilities of Bragg gratings with a phase shift as sensing elements in fib

Effect of intersubband scattering on weak localization in 2D systems

The theory of weak localization is generalized for multilevel 2D systems taking into account intersubband scattering. It is shown that weak intersubband scattering which is negligible in a classical transport, affects strongly the weak-localization correction to conductivity. The anomalous magnetoresistance is calculated in the whole range of classically low magnetic fields. This correction to conductivity is shown to depend strongly on the ratios of occupied level concentrations. It is demonstrated that at relatively low population of the excited subband, it is necessary to use the present theory because the high-field limit asimptotics is shown to be achieved only in classical magnetic fields.Comment: 18 pages, 4 figures. Accepted to Phys. Rev. B 6

Rate Theory of Acceleration of Defect Annealing Driven by Discrete Breathers

Siendo un capítulo de libro es un poco estraño que los campos correspondan a una revista. Tal vez, en vez de coordinador/director deberían ser editores, y en vez de editor, editorial. En cambio faltarían campos como volumen y serieNovel mechanisms of defect annealing in solids are discussed, which are based on the large amplitude anharmonic lattice vibrations, a.k.a. intrinsic localized modes or discrete breathers (DBs). A model for amplification of defect annealing rate in Ge by low energy plasma-generated DBs is proposed, in which, based on recent atomistic modelling, it is assumed that DBs can excite atoms around defects rather strongly, giving them energy ≫ kBT for ~100 oscillation periods. This is shown to result in the amplification of the annealing rates proportional to the DB flux, i.e. to the flux of ions (or energetic atoms) impinging at the Ge surface from inductively coupled plasma (ICP)

Models of Deformation Dependences of Total Integrated Intensity of Dynamical Diffraction in Single Crystals for Various Diffraction Conditions

В работе с помощью теории Чуховского—Петрашеня для деформационной зависимости (ДЗ) интегральной интенсивности динамической дифракции (ИИДД) в кристаллах без дефектов показан характер изменения ДЗ ИИДД с толщиной кристаллов и с вариацией других условий дифракции. На этой основе, а также при использовании ряда экспериментов с реальными дефектными кристаллами и результатов теории полной интегральной интенсивности динамической дифракции (ПИИДД) в кристаллах с дефектами без изгиба построена аналитическая модель ДЗ ПИИДД в кристаллах с дефектами, пригодная для диагностики параметров структурных дефектов в кристаллах.В роботі за допомогою теорії Чуховського—Петрашеня для деформаційної залежности (ДЗ) інтеґральної інтенсивности динамічної дифракції (ІІДД) у кристалах без дефектів показано характер зміни ДЗ ІІДД із товщиною кристалу та з варіяцією інших умов дифракції. На цій основі, а також при використанні ряду експериментів із реальними дефектними кристалами і результатів теорії повної інтеґральної інтенсивности динамічної дифракції (ПІІДД) у кристалах з дефектами без вигину побудовано аналітичну модель ДЗ ПІІДД у кристалах з дефектами, придатну для діягностики параметрів структурних дефектів у кристалах.The paper shows the pattern of change in the deformation dependences (DD) of integrated intensity of dynamical diffraction (IIDD) with crystal thickness and with variation of other diffraction conditions by means of the Chukhovskii—Petrashen theory for the DD of IIDD in defect-free crystals. Relying on this and numerous other experiments with real defective crystals as well as the results of total integrated intensity of dynamical diffraction (TIIDD) in crystals with defects without bend, an analytical model of the DD of TIIDD in crystals with defects is developed, which is feasible for the diagnostics of structural defects in crystals

Optimization of components in development of polymeric coatings for restoration of transport vehicles

It is proved, that for improving the performance characteristics of vehicle parts, including their corrosion resistance and wear resistance, it is advisable to use protective polymeric composite coatings. It is shown that in order to increase the indexes of physical-mechanical and thermophysical properties in the epoxy binder, it is necessary to introduce additives: modifiers, plasticizers, dispersed and fiber fillers. The introduction of dispersed additives into the epoxy binder is actual. It this case, it is effective to use fillers of different dispersity in the complex. The influence of two-component polydispersed filler on the elasticity modulus in flexure of the developed epoxy composite is analyzed. The critical content of a two-component polydispersed filler is found by the method of mathematical planning of an experiment. a mixture of nanodispersed compounds 1 (d = 20 . . . 80 nm) − 0.75 . . . 1.0 pts.wt., a mixture of discrete fibers 1 (l = 0.5 . . . 1.0 mm, d = 18 . . . 25 µm) – 0.2 pts.wt. by the 100 pts.wt. of the epoxy oligomer ED-20. An introduction of the two-component polydispersed filler to the epoxy binder allows significantly to increase the values of the elasticity modulus in flexure of the protective coatings to = 4.8 . . . 5.0hP a. Additionally, the effect of two-component polydispersed filler on the impact resilience of the developed epoxy composite was determined. It is proved that the critical content of a two-component polydisperse filler is: a mixture of nanodispersed compounds 2 (d = 30 . . . 40 nm) − 1.00 . . . 1.25 pts.wt., a mixture of discrete fibers 2 (l = 0.5 . . . 1.0 mm, d = 18 . . . 25 µm) − 0.1 . . . 0.2 pts.wt. by the 100 pts.wt. of epoxy ED-20. An introduction of the two-component polydispersed filler to the epoxy binder allows significantly to increase the values of the impact resilience to W’ = 10.0. . . 10.2 kJ/m2. The obtained results allow us to create polymeric coating with improved indexes of the physical and mechanical properties in complex