Russian Physics Journal最新文献

The energy thresholds and the kinetics of explosive degradation of PETN and its composites is studied experientially under ignition by a laser pulse (λ₀ = 1064 nm, τ_p = 12 ns) depending on the concentration of absorbing additives and the pressure changing in the range from 40 to 600 MPa. A complex dependence of the initiation thresholds on the pressure and additive concentration has been demonstrated. Results are explained by the authors within the framework of the thermal micro-spot model of initiating the transparent explosive components (the hot spot model).

The temperature of the surface of A7 aluminum alloy specimens with TiCuN coatings 1–6 μm thick has been measured during irradiation with intense pulsed electron beams having different energy densities and pulse durations using a high-speed infrared pyrometer. Numerical simulation of the thermal fields for the same conditions shows good similarity to the experimental data and allows temperature dependences to be determined at different depths from the specimen surface and different distances from the beam symmetry axis for coatings of various thicknesses with different melting depths of the aluminum base to be determined together with the lifetime of the liquid phase.

An axisymmetric stationary problem of elastic deformation of a circular cylinder is considered in the case of an impact on the lateral surface of an absolutely rigid ring with angular lines. Equilibrium equations in displacements are used. In this case, the stress and strain tensors have four nonzero components. All stresses are found by calculations, and zones of possible destruction of the material are determined by their maximum values.

The paper studies the structure of TiNi wires of a diameter 60 μm obtained by the conventional technique followed by cryogenic treatment. X‑ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy reveal chemical and phase compositions of thin wires before and after cryogenic treatment. SEM is used to investigate biointegration of a spherical TiNi implant into soft tissues. It is shown that cryogenic treatment of thin TiNi wires provides the formation of two phases B2+B19’ in the structure that indicates to martensite stabilization after cooling. The high integration tie is demonstrated between body tissues both inside and on the surface of the spherical implant.

Calcium phosphate (CaP) coatings modified with Fe–Cu nanoparticles have been manufactured using the micro-arc oxidation (MAO) method. The primary focus was on the morphology, elemental composition, phase composition, and surface charge properties as well as the antimicrobial activity and cytotoxicity of the coatings. It is demonstrated that the addition of the Fe–Cu nanoparticles enhances the antimicrobial properties of the coatings by reducing the number of viable Staphylococcus aureus bacteria and increases the biocompatibility of the coatings. This makes the coatings promising for use in medical implants, providing the necessary composition and porosity along with the improved biological characteristics.

In the present work, atomic force microscopy (AFM) and electron backscatter diffraction (EBSD) analyses are used to study the microstructure of metastable AISI 321 austenitic steel subjected to quasi-static uniaxial tension in the temperature range 213–338 K. The influence of deformation on phase transformations in metastable austenitic steels is shown. The temperature dependence of the volume fraction of the martensitic phase and microhardness are revealed.

The structural-phase states and elemental composition of a layer of M10 steel surfaced on medium-carbon CSN 14331 steel are studied. The surfaced layer represents a multiphase material containing Fe-based solid solution and inclusions of the carbide and intermetallic phases. The mixing entropy is evaluated and the surfaced layer material is shown to belong to medium-entropy alloys. Using MATLAB and the crystallochemical database, the variations of thermodynamic and elastic properties are calculated in the temperature range up to 1600 °C for a model high-speed steel, 72.2 Fe – 12 Mo – 5 Co – 5 Cr – 5 V – 0.8 C, whose composition is close to that of M10 steel.

Sequential excitation of two nonlinear transmission lines with saturated ferrite by one high-voltage pulse has been implemented. The central frequencies of the high-frequency pulses of each line were approximately 3 and 4 GHz. It is shown that this method of excitation of oscillations allows implementing a sequence of radio pulses with a repetition frequency of tens of MHz as well as increasing the energy efficiency of high-frequency pulse generation in the specified frequency ranges.

This mini-review is devoted to the memory of Professor Vladislav Gavrilovich Bagrov, the outstanding Russian physicist, who was especially dedicated to mathematical physics. Amazingly, he heard the music of differential equations obtained from field equations. I belong to the school of theoretical physics created by Prof. Bagrov in Tomsk, where he was my first teacher in mathematical physics and PhD thesis director. In this review, I briefly discuss several popular models of modified gravity in relation with observational data. Note that reasonable modified gravities lead to extremely complicated field equations, which solution can be a real challenge for Prof. Bagrov and his pupils. This is an attempt to look over the horizon in order to understand which final theory may better describe the universe evolution history so that to be the best candidate for understanding gravitational physics and the universe history.

The article discusses an automated fiber-optic security system (FOSS) designed to protect perimeters of objects from unauthorized access. The system utilizes multi-channel CMOS (Complementary Metal Oxide Semiconductor) image sensors to record changes in the light spot, which makes it possible to detect vibration effects on an optical fiber with high sensitivity. The paper presents the development technique and test results for the laboratory sample, which show its operability and prospects for commercialization. The FOSS has the potential to replace outdated systems based on electrical signals, protecting them from electromagnetic interference and is highly accurate in climatic conditions of Kazakhstan.