A mathematical model of the problem of calculating the weight coefficients of a binary neural network is presented. It is proved that in the case of step functions of neuron activation, this model is ...a system of linear inequalities, which is inconsistent for most practical problems. A method for analyzing the system of inequalities is proposed, which allows calculating the values of the weight coefficients and synthesizing the structure of the neural network, thus ensuring the absolute accuracy of the output signals. The algorithm and an example of implementing the proposed method are given.
Unified forms of knowledge representation models in expert control systems are proposed. It is proved that at quantitative measurement of the characteristics of the state of the controlled object, ...the problem of deriving a managerial solution is reduced to the investigation of a combinatorial optimization problem with a linear structure and two-sided inequality constraints. An algorithm for solving such problems is given, which implements the idea of directional selection of variants.
We study the collective dynamics of two distant magnets coherently coupled by acoustic phonons that are transmitted through a nonmagnetic spacer. By tuning the ferromagnetic resonances of the two ...magnets to an acoustic resonance of the intermediate, we control a coherent three-level system. We show that the parity of the phonon mode governs the indirect coupling between the magnets: the resonances with odd (even) phonon modes correspond to out-of-phase (in-phase) lattice displacements at the interfaces, leading to bright (dark) states in response to uniform microwave magnetic fields, respectively. The experimental sample is a trilayer garnet consisting of two thin magnetic films epitaxially grown on both sides of a half-millimeter-thick nonmagnetic single crystal. In spite of the relatively weak magnetoelastic interaction, the long lifetimes of the magnon and phonon modes are the key to unveil strong coupling over a macroscopic distance, establishing the value of garnets as a platform to study multipartite hybridization processes at microwave frequencies.
This paper presents experimental data on the effect of inert (He, N2, Ar, CO2) and reactive (СН4, O2, CF3Br, (CH3O)3PO) gas additives to hydrogen and ambient air on flame blow-off during diffusion ...combustion of a hydrogen microjet emanating from a micronozzle into air. It is found that the addition of the above gases to hydrogen narrows the microjet velocity range of stable combustion of hydrogen. For hydrogen with the additives studied, the critical velocity of flame blow-off depends primarily on the mean molecular weight of the combustible mixture. When the gases are added to the air surrounding the diffusion flame, the critical velocity of flame blow-off is determined by their inhibiting effect on the chemical reactions of hydrogen oxidation. The results can be used to determine the minimum concentrations of flame-suppressing additives required to prevent the ignition and combustion of hydrogen in its accidental releases.
•A composition of the fuel and oxidizer affects stability combustion of Н2 microjet.•Molar weight of additives mixed with H2 affects combustion limits of Н2 microjet.•Reactivity of additives mixed with air affects combustion limits of Н2 microjet.•Results are interesting for the fire safety of H2 at its emergency emissions.
Determining the centrality of a collision, or the impact parameter, in heavy-nucleus collisions is important for the analysis of all experimental data and their comparison with theory. One of the ...methods for this is to measure the number of spectators using a hadron calorimeter arranged at a small angle to the nuclear beam. It is shown that the accuracy in determining the impact parameter at the attainable energy resolution of the hadron calorimeter is inadequate for using the calorimeter in the MPD/NICA and CBM/FAIR projects. The error is as large as 35% at the beam energy of 2.5 GeV even for peripheral collisions. Secondary processes during the motion of spectators through a nucleus make an additional contribution to the error for central and mid-central collisions.
We report ferromagnetic resonance in the normal configuration of an electrically insulating magnetic bilayer consisting of two yttrium iron garnet (YIG) films epitaxially grown on both sides of a ...0.5-mm-thick nonmagnetic gadolinium gallium garnet (GGG) slab. An interference pattern is observed and it is explained as the strong coupling of the magnetization dynamics of the two YIG layers either in phase or out of phase by the standing transverse sound waves, which are excited through a magnetoelastic interaction. This coherent mediation of angular momentum by circularly polarized phonons through a nonmagnetic material over macroscopic distances can be useful for future information technologies.
Special features of the behavior of the pion-production cross section as a function of the mass number of the target nucleus are discussed for incident-deuteron fragmentation to pions produced in the ...twice-cumulative kinematic region. The fact that, for such pions to be produced in deuteron-nucleus collisions, the target nucleus should be heavier than the proton is the most peculiar to them. They are produced owing to the high-momentum component in both colliding nuclei. The dependence of the production cross section for twice-cumulative pions on the target mass number is simulated, and the effect of various models used to describe the structure of the target nucleus at small nucleon-nucleon distances is examined.
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In this paper, we examine the combustion of a hydrogen microjet outflowing from a curved channel with a round micronozzle. Jet flows that are generated using rectilinear and curved channels differ ...in that, in the second case, Dean vortices make a noticeable contribution to the formation of the jet and its combustion. The interaction of the latter with Kelvin–Helmholtz vortices, the formation of which is typical for flows with a velocity shift, causes changes in the combustion characteristics. They include spatial distortions of the laminar flame zone near the nozzle exit, the area of turbulent combustion downstream, as well as the turbulent flame under the conditions of its separation from the nozzle exit and the cessation of laminar combustion in the initial section of the flow. The results of these studies provide the possibility to understand better the combustion features of hydrogen microjets under conditions of their hydrodynamic instability.
The paper describes how the acoustic impact on an impinging jet induces a maldistribution in the radial velocity field within the nearwall zone of spreading jet. The r.m.s. velocity pulsation level ...in the nearwall jet is lower than in the natural jet. A higher length of the laminar flow zone in a microjet was noted. The development of sinusoid-type instability facilitates a higher combustion efficiency for a propane-butane fuel mixture in the impinging microjet; this reduces the soot emission. The tests demonstrated that the zero acoustic impact makes the flame spectrum more yellow (including the flame from the nearwall zone). This testifies about deficiency of oxidizer (air) and soot presence in the combustion products. The combustion efficiency for diffusive flame in the impinging jet depends on the nozzle diameter and nozzle-target distance.
•Exchange spin waves are excited in the transition layer of the epitaxial YIG film.•Spin waves are sensitive to the magnetization distribution over the YIG film thickness.•A method of non-destructive ...testing of the layered structure YIG film is proposed.
The results of modelling of the excitation and propagation processes of exchange spin waves (ESW) in epitaxial films of yttrium iron garnet (YIG) are presented. It is shown that the origin of the efficient ESW excitation is magnetic inhomogeneity, which is always present in a thin transition layer at the interface between a magnetic film and a nonmagnetic substrate. It is found that the parameters of magnetic inhomogeneity significantly affect wave characteristics of the emitted ESWs. A method was proposed for employing ESWs to measure the magnetization distribution parameters over the thickness of the YIG film and the ESW dissipation parameter. The measured parameters were used to calculate the dispersion and attenuation of the ESWs, define their amplitude characteristics in continuous and pulsed regimes, and estimate their phase losses. It is shown that dissipative losses of ESWs are not significant. More significant losses can occur due to phase dispersion on non-parallel reflective surfaces of the YIG film. It is demonstrated that such phase losses can be significantly reduced by precision optical polishing of the YIG film samples.
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