We experimentally study nanowire-shaped spin-Hall nano-oscillators based on nanometer-thick epitaxial films of Yttrium Iron Garnet grown on top of a layer of Pt. We show that, although these films ...are characterized by significantly larger magnetic damping in comparison with the films grown directly on Gadolinium Gallium Garnet, they allow one to achieve spin current-driven auto-oscillations at comparable current densities, which can be an indication of the better transparency of the interface to the spin current. These observations suggest a route for improvement of the flexibility of insulator-based spintronic devices and their compatibility with semiconductor technology.
Abstract The polymers and composites study of is to the present day an actual topic of many research scientists. Experimental studies of antifriction polymer and composite materials are widespread. ...But analyzing the performance of materials under different conditions does not lose its relevance. This is due to the limited data on the materials behavior in open sources, both statically and dynamically. The article deals with spherical bridge bearing manufactured by “AlfaTech”, Perm, Russia. The bearing includes a steel balancer with a ball segment in contact with the lower steel plate through a spherical protective antifriction layer. The material of the protective layer may vary. Several options for antifriction layer materials both polymer and composite are reviewed in the work. The geometry of structural elements influences its behavior. A particular effect is observed in elements made of plastic. The main part of parameters was considered in this article, such as thickness and physico-mechanical properties of polymer sliding layer. The article considers the value influence of the friction coefficient on the interaction of contact surfaces. It was obtained that the maximum values of contact parameters decrease with increasing sliding layer thickness. The paper deals with the description of viscoelastic behavior of modern polymers and composites used as sliding antifriction layers within.
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Different methods for measuring random wavefront tilts are considered. Possibilities of measuring the Fried parameter by the differential method in problems of turbulence sensing and adaptive ...optics are determined. Comparative measurements of the turbulence strength along a horizontal path were carried out by two optical methods: (1) with a differential turbulence meter and (2) passive method based on image jitter measurements with a high-speed digital video camera mounted on a small astronomical telescope and real-time processing algorithms. Possible differences in the measurement results are discussed. Patterns of the evolution of the convective motion of a medium inside a volume in terms of the vector velocity field and scalar temperature and pressure fields are derived on the basis of numerical solution of the set of Navier–Stokes equations. Ways of improving a wavefront sensor for high-precision phase measurements in both Kolmogorov and non-Kolmogorov turbulence are suggested.
We study the role of electron-electron interactions near integer and abelian fractional quantum Hall (QH) transitions using composite fermion (CF) representations. Interaction effects are ...encapsulated in CF theories as gauge fluctuations. Without gauge fluctuations, the CF system realizes a ‘dual’ representation of the noninteracting QH transition. With gauge fluctuations, the system is governed by a gauged nonlinear sigma model (NLSM) with a θterm. While the transition is described by a strong-coupling fixed point of the NLSM, we are nevertheless able to deduce two of its properties. With 1/r interactions, (1) the transition has a dynamical exponent z=1, and (2) all transitions are “superuniversal”: fractional and integer QH transitions are in the same universality class. With short-range interactions, z=2 and the fate of superuniversality remains unclear.
This paper presents the results of our research into improving the design and fabrication quality of custom-molded corrective insoles by developing modern computer-aided modeling and programming ...methods that factor in changes in the mechanical properties of materials during use. This paper proposes a method for designing custom corrective insoles using the optimal insole structure and material. We used OrthoModel to design an insole model in a solid-body format and then exported it as an STL file. Then, using FreeCAD, we converted the STL file to a STEP file to better adapt the model for further use and analysis. Using the Ansys environment, we devised a finite element model for insole deformation and investigated the behavior exhibited by the material of the insole arch under different loads and combinations of EVA materials with varying hardness. The model yielded the stresses and deformations experienced by the insole arch during use, depending on the combination of the material and the geometry of the foot, and those stresses and deformations were experimentally verified. The calculated values for insole deformation served as input for programming the processing of the insole with a CNC machine. With a 3D insole model, it is possible to both fabricate the insole with a CNC machine and to print the insole with a 3D printer. The calculated cost price of fabricating custom-molded corrective insoles attests to the competitiveness of the proposed technique.
In this paper we report on results of an investigation of a transparent mesh electrode in a wide wavelength range 550–2000 nm with low electrical resistance manufactured by laser ablation with using ...an aluminum film with a thickness of 30 pm on a polyimide substrate with a thickness of 20 μm. The method is implemented using a fiber ytterbium nanosecond laser with a wavelength of radiation 1064 nm. The structure we have obtained has a transmittance >50% in the designated spectrum range and the electrical resistance <1.5 Ω/sq.
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