Bulletin of the Russian Academy of Sciences: Physics最新文献

Glass–water and glass–air interfaces were visualized by second-harmonic generation microscopy. It was shown that the electrostatic surface potential can be determined from the recorded intensity of the signal from the glass surface in contact with solutions with different pH. Comparison of images of glass in contact with air and an aqueous solution at pH 2 hinted towards the similarity in the molecular structure of these interfaces.

A quantum memory scheme consisting of three optical resonators that form a photonic molecule with a programmable spectrum topology is studied. The dependence of the spectrum on the tuning parameters is analyzed to perform effective signal transfer to memory. The dynamics of the field in individual resonators is calculated for use in processing.

We report the peculiarities of the electro-optic beam steering device development utilizing [001]‑cut Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (PMN–PT) crystals possessing tetragonal symmetry. Using surface fixation, we successfully fabricated the five-layer optical phased array (OPA) featuring a stable cascaded pattern of 180° domains with a low concentration of ferroelectric-ferroelastic domains. The electro-optic coefficient γ₃₃ of PMN–PT was estimated to be 134 pm/V and the quality of the cascaded domain structure was acceptable for achieving a steering ability of 0.32°/V/μm. Further optimization of domain engineering for PMN–PT crystals can significantly enhance device performance.

The effect of nozzle diameter on the mechanical properties of polymers reinforced with short fibers is critical for optimizing both print quality and structural performance in fiber-reinforced composites 3D‑printed using fused filament fabrication. This study investigated three types of polymer composites based on acrylonitrile butadiene styrene reinforced with carbon, glass, and basalt short fibers. The study involved experiments on monofilament samples before and after manufacturing process to evaluate and compare the effective tensile strength and stiffness properties of filaments reinforced with different materials.

The results of studying kinetics of strength decrease for two types (polyethylene and polyamide) of polymer fibers at X-ray irradiation. A structural-kinetic model of radiation induced changes in strength of fibers is considered, which accounts for the opposite effect of degradation and crosslinking of macromolecules on the oriented polymer (fiber) strength.

We present a version of the numerical analysis of the relationship between maximum strains on the ground surface and in an underground pipeline based on the results of solving the corresponding problem of the stress–strain state that arises as a result of the appearance of cavities of different geometries in the soil mass.

We proposed methods for developing predictive models of concrete gravity dam crest displacement. A deterministic finite element analysis (FEA) model is presented along with a method for identifying its mechanical properties. Performance of FEA model is compared to booster regression trees statistical model with hyperparameter tuning. Resulting models demonstrate excellent accuracy.

The study of multiphase systems based on magnetic fluids under external magnetic influence is a relevant direction in the development of contactless methods for controlling non-magnetic objects. This work aims to investigate non-magnetic inclusions in magnetic fluid. The results have been obtained through experimental methods and computer simulations using FEMM software.

We investigated the possibility of accelerating the numerical simulation of transient processes in ANSYS software when calculating superelastic dampers based on shape memory alloys. The work compares two approaches to three-dimensional modeling of dampers: the superelasticity model and the thermomechanical model, demonstrating their satisfactory agreement. It is noted that simulating slender structures, typical of superelastic dampers, in a three-dimensional formulation requires significant computational time. As a solution, the use of beam finite elements with a thermomechanical model is proposed. It is shown that this approach provides reliable results while substantially reducing computation time and is optimally suited for analyzing typical beam-like damper configurations.

A series of seven samples of water-based magnetic fluid stabilized with a double surfactant layer was synthesized. The magnetic properties of the synthesized samples were determined as a function of their concentration. The obtained concentration dependences of the initial static magnetic susceptibility for all samples are described by a third-degree polynomial of the Langevin susceptibility with a negative cubic term, which contradicts the existing theoretical models.