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The features of radiative relaxation of self-trapped excitons (STEs) in CsI crystals under lowering of the lattice symmetry by low-temperature (83 K) uniaxial elastic deformation (e = 0.5–0.7 %) are studied using the methods of luminescence spectroscopy. The sensitivity of intrinsic luminescence (peaked at 4.27 eV and 3.67 eV) to elastic deformation and ionizing radiation is detected. It is determined that the luminescence enhancement in elastically deformed CsI crystals is caused by the enhancement of 3.67 eV luminescence related to the STEs with an asymmetric configuration (weak off-center), while the 4.27 eV luminescence ascriebed to the STEs with a symmetric configuration (on-center) becomes suppressed. The study of the luminescence temperature dependence in CsI exposed to elastic deformation allowed us to determine the potential barrier Δ2 = 8 meV between the radiative states of the on– and weak off-center configurations of STEs.

This work proposes an original approach to the study of trihalide centers in a KCl matrix in the field of local and plastic deformation. Local lattice deformation is carried out by purposeful doping of the KCl crystal with light homologous cations, as well as bivalent impurities, which create dipole strontium complexes to maintain the electroneutrality of the lattice. Plastic deformation, which creates paired vacancy defects in the lattice, divacancies and vacancy quartets, is realized at room temperature within the degree of relative uniaxial deformation of 3–5%. After subsequent cooling down to 80 K the deformed crystal was additionally irradiated with X-rays. The absorption spectra of the crystals subjected to two types of deformation and additional isodose irradiation by X-rays were recorded in a special cryostat at 80 K. The spectral characteristics and formation efficiency of V-type centers, lithium- and strontium-containing centers in the field of pre-irradiation dipole complexes have been considered.

A digital technology for scanning the X-ray luminescence, tunnel luminescence, and thermostimulated luminescence spectra in the spectral range from 200 nm to 850 nm is experimentally demonstrated using the example of a NaCl crystal, which is part of the group of alkali halide crystals. This is done with the specified spectrum intervals and scanning speed using a high-aperture monochromator MSD-2 and a photoelectronic multiplier type H 8259 of the company “Hamamatsu”, operating in the photon counting mode, controlled by special programs SpectraScan and ThermoScan. The obtained experimental data are digitally converted for further processing of the graphical representation of the results using the OriginPro software package, which allows you to draw up graphical dependencies of the spectra and perform their mathematical processing.

Ultrafast excited-state dynamics of CuBr3- complex was studied in acetonitrile and dichloromethane solutions using femtosecond transient absorption spectroscopy with 18 fs temporal resolution and quantum-chemical DFT calculations. Upon 640 nm excitation, the CuBr3- complex is promoted to the ligand-to-metal charge transfer (LMCT) state, which then shortly undergoes internal conversion into the vibrationally hot ligand field (LF) excited state with time constants of 30 and 40 fs in acetonitrile and dichloromethane, respectively. The LF state nonradiatively relaxes into the ground state in 2.6 and 7.3 ps in acetonitrile and dichloromethane, respectively. Internal conversion of the LF state is accompanied by vibrational relaxation that occurs on the same time scale. Based on the analysis of coherent oscillations and quantum-chemical calculations, the predominant forms of the CuBr3- complex in acetonitrile and dichloromethane solutions were revealed. In acetonitrile, the CuBr3- complex exists as [CuBr3(CH3CN)2]-, whereas three forms of this complex, [CuBr3CH2Cl2]-, [CuBr3(CH2Cl2)2]-, and [CuBr3(CH2Cl2)3]-, are present in equilibrium in dichloromethane.

The efficiency of stabilization of H centers as well as its dependence on the degree of uniaxial deformation are considered within the framework of the modified geometric model of alkali halides. It is shown that stabilization of H centers is difficult in KI and RbI crystals, while in other NaCl-type crystals it becomes quite probable. Under uniaxial deformation, the interstitial space, in which the defect will be located, decreases, and the efficiency decrease. In the case of cesium halides, the orientation of the H centers takes place predominantly in the direction; therefore, the criteria for their stabilization differ from the NaCl-type alkali halide crystals. According to calculations, in CsI, large displacements of the nearest neighbors are required to stabilize H centers; while in CsBr their stabilization becomes sensitive to the effect of uniaxial deformation. The efficiency of H center stabilization obtained by the geometric model is compared with the corresponding efficiencies obtained from the theory of local excitations and the calculated total probability of accumulation of H centers under the influence of uniaxial deformation.

The paper deals with the properties of octagraphene nanoribbon determined in terms of the local spin density approximation and nonequilibrium Green’s function, namely transmission spectra, current–voltage characteristics (I–V curves), and differential conductivity of the zigzag-edged octagraphene nanoribbon obtained after the removal of carbon atoms from its center and saturation with hydrogen atoms. The I–V curves are characterized by a section with negative differential resistance caused by the resonant-tunneling of quasiparticles. The dI/dV curve shows similar changes. It is found that in the zigzag-edged octagraphene nanoribbon (with the network consisting of hexagons and a carbon bridge), spin-down quasiparticles are blocked in the energy range from –1.65 to –0.5 eV. This behavior of the transmission spectrum allows octagraphene nanoribbons to be applied in creation of energy spin filters. It is shown that the spin-polarized current in zigzag-edged octagraphene nanoribbon (with the network consisting of pentagons and a carbon bridge) with spin-up quasiparticles significantly exceeds the current in that with spin-up and spin-down quasiparticles. This effect allows the selection of spin-up quasiparticles at a certain voltage applied. The obtained results can be useful in the new developments of spintronic devices.

The regularities of statistical distributions of breaking strength of high-strength ultraoriented monofilaments and polyfilament fibers consisting of several hundreds single ultrahigh-molecular-weight polyethylene (UHMWPE) fibers were analyzed using the Weibull and Gauss models based on a large array of measurements (50 identical samples in each series). It was shown that the distribution of strength of polyfilament UHMWPE fibers can be described both in terms of the normal Gauss distribution and using the standard Weibull distribution function. At the same time, the strength distribution in UHMWPE monofilaments drawn to an ultimate draw ratio of 120 is governed by normal distribution. The reasons for the detected difference in the types of statistical distributions of breaking strengths in high-strength UHMWPE mono- and polyfilaments are discussed.

Crystals of glycinium dicitratoborate monohydrate H3NCH2COOH[B(C6H6O7)2] · Н2О have been synthesized and selected for the first time. Their structure is determined by X-ray diffraction analysis: triclinic system, sp. gr. Р$$\bar {1}$$, and Z = 2. The crystals consist of cation–anion layers, in which all structural units (dicitratoborate anion, glycinium cation, and crystallization-water molecule) are bound firmly by numerous hydrogen bonds.

Luminescence excitation spectra of BaBrI single crystals doped by divalent lanthanide ions are studied using synchrotron radiation excitations from the MAX IV 1.5 GeV storage ring. The energy of the edge and the formation of core cation exciton as well as the energy threshold of the multiplications of electronic excitations is found. It was clearly established the energy transfer from intrinsic luminescence centers to Sm2+ and Eu2+ ions.

The processes of temperature quenching of the luminescence of the self-trapped excitons (STEs) from 93 to 200 K in the conditions of applied elastic low-temperature deformation for several alkali-halide crystals (AHCs) are presented in the paper. The theoretical explanation of the influence of low-temperature uniaxial deformation on the formation of the luminescence of the STEs was done. The increase in activation energy of the temperature quenching of the luminescence of the STEs, narrowing of the emission bands, increase in the frequency of the active oscillations of the STEs and the decrease in the Huang-Rhys parameter are shown as the results. These changes indicate a weakening of the exciton-phonon interaction in elastically deformed AHCs, which, in turn, leads to an increase in the probability of radiative annihilation of excitons.

The paper presents the results of a comprehensive study of effects that In3+ ion impurities have on the optical properties of SrF2 and SrF2:Ce3+ crystals. The investigations were carried out both by optical spectroscopy methods and ab initio quantum chemical calculations. To estimate the effect of indium impurities on the optical band gap of the crystals, the DFT calculations were performed for SrF2 crystals doped with different concentrations of In3+ ions. The study of SrF2 crystals co-doped with Ce and In ions reveals the highly effective role of indium ions in reducing the electron trapping efficiency in the processes of excitation transfer to an activator. This improvement is associated with some change in the band gap of the crystals caused by indium doping, which is confirmed by both theoretical and experimental results.

BaBrI crystals activated by Sm2+ ions were synthesized by the Bridgman method. The Sm content in the samples was analyzed by the method of mass spectrometry with inductively coupled plasma. The results of the study of the optical and scintillation characteristics of the synthetic crystals, such as photoluminescence, X-ray luminescence, and absorption spectra, are reported. The light yield of the luminescence of the studied samples was estimated.

The processes of radiation defect creation and radiative relaxation of electronic excitations under applied local or/and uniaxial elastic deformation have been studied in NaCl crystals by means of optical absorption, luminescence and thermoactivation spectroscopy methods. In NaCl:Li at 80 K, X-ray-induced absorption bands peaked around 3.35 and 4.6 eV have been detected and ascribed to interstitial halide atoms located nearby Li impurity cations, HA(Li) centres. Subsequent thermal annealing of HA(Li) centres leads to the formation of polyhalide centres responsible for the absorption band at 5.35 eV. In an X-irradiated and stressed NaCl:Li crystal (degree of uniaxial elastic deformation of ε = 0.9%), the peak of thermally stimulated luminescence at ~115 K is composed of the ~2.7-eV emission appearing, in our opinion, due to the recombination of the electron, thermally released from an F′ centre, with a hole-type HA(Li) centre. The applied uniaxial elastic stress facilitates the self-trapping of anion excitons in regular regions of a NaCl lattice and impedes the energy transfer by mobile excitons to impurities/defects and, in turn, attenuates the Br-related luminescence peaked at 3.95 eV with respect to the π-emission of self-trapped excitons (~3.35 eV). The 3.95 eV emission has been detected in a natural NaCl crystal containing homologous Br impurity ions.

Using X-ray luminescence spectra, the enhancement of both σ-luminescence of self-trapped excitons and Ех luminescence (band maxima at 3.89 and 3.1 eV, respectively) has been revealed for the first time in RbI single crystals exposed to elastic uniaxial stress at 93 K. The intensity of these emissions increases linearly with the relative degree of applied uniaxial deformation of the crystal up to ɛ = 1%, while the luminescence undergoes saturation at higher values of ɛ. The behavior of the I = f (ɛ) dependence for σ and Ех emissions suggests that Ех luminescence is intrinsic, and is connected with the radiative relaxation of self-trapped excitons in the field of local deformation of a RbI regular lattice.

The kinetics of the development of the structural phase transition of the first order in monodisperse samples of tetracosane C24H50 has been studied using Fourier-transform IR spectroscopy. Temperature dependences of frequencies and intensities of rocking (in the region of ν ~ 720 cm–1) and bending (in the region of ν ~ 1470 cm–1) vibration modes of CH2 groups in trans methylene sequences in crystalline cores of elementary lamellae has been analyzed. It has been shown that the solid-phase transition of the first order develops by the heterogeneous mechanism in a narrow temperature interval ΔT ~ 2 K according to the theory of diffuse phase transitions of the first order and is caused by changes in the symmetry of crystallographic cells.

We analyze heat effects associated with the solid-state phase transition in ultrahigh molecular weight polyethylene from the unstable monoclinic phase into thermodynamically stable orthorhombic phase. The model proposed here for the structure of supramolecular formations of monoclinic phase does not contradict to earlier X-ray diffraction data for this polymer.

A solvent-free route to high performance ultra-high molecular weight polyethylene (UHMWPE) film threads is currently under intensive development. It involves compaction/sintering of UHMWPE reactor ...

Statistical analysis of distribution of the elasticity modulus (E) and strain (elongation) at break (eb) of commercial oriented polyamide-6 (PA-6) fibers has been performed in the framework of the Gaussian and Weibull models. Results of analysis confirm the dualism of the distribution of E and eb values of this oriented high-strength polymer, which consists in the validity of both the normal Gaussian distribution and the standard Weibull distribution function for this material.

Using the small-angle synchrotron X-ray diffraction method at the research facility “BELOK” of the Kurchatov synchrotron radiation source at the NRC Kurchatov Institute, it was shown that the first-order solid phase transition in tetracosane C24H50 passes according to a heterogeneous mechanism in a narrow temperature range ΔT ~ 1 K in accordance with the theory of diffuse phase transitions.

The absorption spectra of X-ray irradiated alkaline earth fluoride (CaF2, SrF2, BaF2) crystals doped with Sm, Нo, Er, Tm ions are investigated by thermal bleaching of the sample in the 300–700 K temperature range. X-ray irradiation creates absorption bands of inter-configuration 4fn-4fn−1-5 d1 transitions of divalent impurity ions and F3− and (F2−)ii hole centers. The thermal oxidation of the divalent RE ions have been observed. Two possible mechanism of thermal oxidation of divalent lanthanide ions in alkaline-earth fluorides are discussed.

The features of using the Bridgman method for growing alkaline earth halides crystals BaBrI, BaClI, and SrBrI are discussed. The results of the study of scintillation characteristics of grown crystals activated by europium ions are presented. The actual content of europium in crystals is determined and the values of the luminescence yield and decay time are estimated. X-ray luminescence and absorption spectra of the obtained crystals are given.

The results of nonempirical quantum chemical calculations of CaF2, SrF2, and BaF2 crystals that were activated by In3+ and Ga3+ ions have been presented. The calculations were performed in the framework of density functional theory using the VASP software complex. The estimation of the width of the band gap of defect-free crystals have been carried out by different methods and the influence of impurity ions on the band gap width has been estimated as well as the possibility of getting rid of shallow traps by introducing an impurity of indium or gallium has been investigated.

Using the experimental method of highly sensitive thermoactivation spectroscopy, we studied the spectra of thermally stimulated luminescence (TSL) of purified crystals of NaCl and NaCl-Li under low-temperature (95 K) elastic deformation ( ) in a wide range of the spectrum (200¸850 nm). In the TSL of a NaCl crystal, the dominant peak is an -center, whose intensity doubles during low-temperature deformation and has a maximum of thermal damage at 165–170 K, scanning of which corresponds to the maximum of the TSL spectrum at 3.5 eV. The spectrum of the TSL -peak and the X-ray luminescence coincide and have the same nature – the radiative relaxation of self-trapped excitons upon recombination of mobile holes with electrons. In NaCl-Li TSL, the dominant peaks are F/ and HA (Li) centers, the intensity of which increases 10-fold during low-temperature deformation and having maximum thermal destruction at 110 K and 125 K, respectively. When scanning the TSL spectra at peaks 110K and 125K, we observed radiation with maxima at 2.72 eV and 2.69 eV. An analysis shows that a light lithium cation in the NaCl-Li lattice creates a local deformation as a result of which HA (Li) centers appear. Elastic deformation further stimulates the formation of HA (Li) -centers, evidenced by a 13-fold increase in the intensity of the TSL peak at 125K.

The influence of the gauge length l0 of a sample on the modulus E of ultraoriented film filaments of ultra-high-molecular-weight polyethylene (UHMWPE) has been elucidated. The filament samples are obtained by a multistage orientation drawing on a contact heater with achieving extremely high draw ratios as large as λ = 120. Precursors were xerogels prepared by the drying of 1.5% UHMWPE gel solutions in decalin. A noticeable gain in “methodical” quantity E from 100 to 230 GPa at l0 increasing from 10 to 80 mm with a damping behavior has been established. The E(l0) dependence is shown to be described via the empirical equation that allows the E value to be predicted as a function of l0. According to the prediction, a saturation of the true value E with a yield to a plateau at E = 242 GPa occurs at l0 = 200 mm.

This work is devoted to the study of the influence of ultrasonic treatment on the properties of cationic bitumen emulsion for patching repair of roads. For the first time, the influence of high-frequency sound treatment on the technological properties of road bitumen emulsion EBK-2 was studied. It was shown that treatment of a bitumen emulsion with ultrasound increases its homogeneity by 25%. Due to this, during the emulsion breaking, bitumen is distributed more evenly over the surface of the stone material. It results in a better formation of contact between crushed stone (slag) and bitumen emulsion. The ultrasonicated emulsion EBK-2A is a promising material for improving the quality of patching, its viscosity decreases by 1.6 times. With a decrease in viscosity, the emulsion becomes more mobile and better envelops the grains of stone material. This is especially effective for crushed stone materials based on blast furnace or steelmaking slag with their highly developed rough surface.

The optical spectra of BaBrI crystals activated by divalent samarium were studied. The samples exhibit bright luminescence in the red region of spectra due to 4f6–4f6 and 4f55d1–4f6 transitions of Sm2+ ions. Luminescence exhibits strong temperature dependence in the range 7–300 K. At low temperatures, luminescence associated with parity-forbidden 4f6–46f transitions from 5D0 and 5D1 states is observed. Coloring of the crystals after irradiation by ultraviolet light and long afterglow luminescence of BaBrI:Sm2+ were detected.

This paper presents the results of ab initio calculations of F centers in a number of crystals of mixed barium halides. The calculations were performed using the density functional method and the PBE0 hybrid functional. On the basis of the calculation results, layout of the location of the main levels of F centers in the band gap of the crystals under study was made.

The study of the mechanisms of formation of radiation defects to ensure the transparency of optical materials under the influence of radiation, temperature and stress of various types of deformation is an urgent task at the present time. For this purpose, the mechanisms of formation of halogen centers (V2, V3, V4A) when the lattice symmetry is lowered by the light cation field (Na), plastic and elastic deformation in a KI, KCl and KBr crystals are studied. Absorption spectra of this crystals under X-ray irradiation in the isodose mode for 3 hours at 90 K, pre-doped with Na ions, undergo plastic deformation (4%) at room temperature and elastic deformation (1.5%) at 90 K. Lowering the lattice symmetry by light cations and plastic deformation of the KI, KCl and KBr crystals leads to an increase in radiation defect formation, elastic deformation – leads to a decrease in radiation defect formation, and therefore to an increase in luminescence.

International audience; By using the ID13 nanofocus beamline of the European Synchrotron Radiation Facility (Grenoble, France), an X-ray diffraction study of a "virgin" particle of ultra-high molecular weight polyethylene (UHMWPE) taken directly from the powder synthesis products and not subjected to any external mechanical action was carried out. The X-ray diffraction curves obtained by scanning a randomly selected region of the particle 100 × 20 μm in size with a 0.3 × 0.3 μm microbeam with a horizontal step of 2 μm and vertical step of 0.5 μm exhibited reflexes from the metastable monoclinic phase along with reflections from the orthorhombic phase. It can be supposed that it could be caused by the stresses that developed at specific structure formation during slurry synthesis and were preserved at cooling to room temperature and solvent evaporation. The possibility of the monoclinic phase localization in various morphological formations is discussed.

The research has been supported by the grant of the Ministry of Education and Science of the Republic of Kazakhstan AP08052562. In addition, the research of AIP has been supported by the Latvian- Ukrainian Grant LV-UA/2018/2., The paper deals with the model research of electric transport characteristics of stressed and non-stressed FeSe monolayers. Transmission spectra, current-voltage characteristic (CVC) and differential conductivity spectra of two-dimensional FeSe nanostructure have been calculated within the framework of the density functional theory and non-equilibrium Green's functions (DFT + NEGF). It has been shown that the electrophysical properties depend on the geometry of the sample, the substrate, and the lattice constant. On CVC of non-stressed sample in the range from -1.2 V to -1 and from 1.2 V to 1.4 V, a region of negative differential resistance (NDR) has been observed. NDR is at both signs of the applied voltage due to the symmetry of the nanostructure. d2I/dV2 is used to determine the nature of the electron-phonon interaction and the features of quasiparticle tunnelling in stressed and non-stressed samples. The results obtained can be useful for calculating new elements of 2D nanoelectronics. © 2020 D. Sergeyev et al., published by Sciendo 2020. --//-- Published under the CC BY 4.0 license., Ministry of Education and Science of the Republic of Kazakhstan AP08052562, LV-UA/2018/2; The Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

Using powerful synchrotron X-ray radiation of the beamline “Belok” operated by the National Research Center “Kurchatov Institute,” we perform X-ray diffraction (XRD) study of an intact, virgin (not subjected to any external mechanical loads) particle isolated from reactor powder of ultrahigh molecular weight polyethylene. Along with the peaks originating from the orthorhombic phase, we detect the peaks characteristic of the monoclinic phase that is stable only under mechanical stress, suggesting that the mechanical stress that leads to the formation of the monoclinic phase and persists at room temperature develops during the polymer synthesis. The monoclinic phase gradually disappears when the particle is heated stepwise in increments of 5 K, and its peaks become undetectable when the temperature reaches 340 K. We contrast the results obtained for the phase composition of the virgin particle to those for a tablet prepared by compaction of the same reactor powder at room temperature. XRD analyses of the tablet were performed on D2 Phaser (Bruker) instrument. The monoclinic phase that originates during the polymer synthesis and the one that forms in the tablet during compaction have different parameters. We discuss the mechanisms by which these two different monoclinic phases originate during the processes involved.

This paper concerns the development of oil-filled, heat-resistant aromatic polyamide Phenilon C-2-based composites with high physicomechanical characteristics, an advantage that can withstand loads of up to 25 MPa and operating temperatures of up to 250°C in friction units. When producing oil-filled, Phenilon C-2-based nanocomposites with 300–320°C molding temperature, the choice of oils is limited and depends on their ability to maintain lubricating properties at high temperatures. The physicomechanical and tribological test results using different friction machines prove oil filling’s high efficiency in creating a stable lubricating film on a tribocontact and in improving the tribological properties of polymer composites. Research results helped outline the range of the most promising hybrid fillers for Phenilon C-2-based polymer composites and lubricants for oil filling, which contribute to the formation of a long-lasting lubricating film on a tribocontact. The combination of the experimental studies and a scientifically based approach to predicting the properties of polymer nanocomposites makes possible expedited development of new materials with high target characteristics. The technology of the production and use of these oil-filled polymers refers to nontraditional areas of plastic processing; however, the world statistics of production and consumption of polymeric friction and wear inhibitors shows that these materials are one of the most promising ways to reduce operating losses.

For the first time, the statistical distribution of Young’s modulus and of strain at break of ultra-high-molecular-weight polyethylene (UHMWPE) gel-cast highly oriented film threads have been investigated by employing the Weibull model. These have been produced by the multi-stage hot-zone drawing technique. It has been shown that the results of a large number of mechanical measurements for the two series of UHMWPE film threads drawn to an ultimate draw ratio (λ) of 120 from xerogels formed from 1.5% solutions of UHMWPE in decalin or paraffin oil (50 samples in each case) can be satisfactorily described in the framework of the standard Weibull distribution. The values of Weibull modulus and scale factor have been estimated for the two film threads series investigated. It has been found that the scatter in the experimental data depends on the solvent nature and the mechanical characteristic analysed.

The X-ray luminescence spectra at low temperature (90K) uniaxial deformation were researched for KI and KI-Na crystals, that were stored for more than 10 years. The following regularities were observed: firstly, the intensities of the intrinsic emission bands at 3.3 eV ( π ) and 4.1 eV ( σ ) become equal in comparison with freshly grown crystals; and secondly, with an increase in the degree of low-temperature uniaxial deformation, a gradual shift of the emission spectra occurs in two directions: the luminescence maximum at 3.3 eV shifts towards short wavelengths, the final position is fixed at 3.9 eV, which practically merges with σ -luminescence; the radiation maximum at 3.0 eV (Ex-radiation) is shifted toward long wavelengths, the final position which is fixed at 2.8 eV. Thus, low temperature uniaxial deformation leads to the separation of the emission spectra at 3,3 eV( π ) → 3,9 eV and 3.0 eV ( Ex ) → 2,8 eV, which are interpreted by the separation of weak → on and weak → strong exciton configurations , respectively

Plastic deformation and fracture of Al/SiC metal matrix composite have been numerically simulated in three mechanical tests (tension, compression, shear) with account for the microstructure and rheology of the composite components. A description is given of the formation mechanisms of stress concentration zones and local plastic deformation zones which make the stress-strain state inhomogeneous on the microscale. Distribution fields are obtained for the stress stiffness coefficient and the Lode-Nadai coefficient depending on the strain. Damage accumulation is simulated and damage distribution fields in the composite matrix are constructed with regard to the revealed stress-strain evolution laws. The strain dependences of the fraction of finite element nodes for which the fracture condition is fulfilled are determined. The dependences are used to estimate the damage accumulation rate in the composite matrix for each type of loading.

Statistical analysis of distribution of the tensile strength of commercial oriented polyamide-6 (PA-6) fibers has been performed in the framework of the Gaussian and Weibull models using a large data array of the results of measurements for a large number (50) of identical samples. Using the example of PA-6, the dualism of strength distribution in oriented high-strength polymers is demonstrated for the first time, which consists in the validity of both the normal Gaussian distribution (characteristic of viscoelastic and plastic materials) and the Weibull distribution (characteristic of brittle materials).

The paper reports the impact of continuous laser treatment of slurry coatings on the surface’s physical and mechanical properties and wear resistance. Laser at different powers was applied to 12C2N4A-SH steel samples submerged in slurries of diverse composition. The effect of various compositions and depths are examined to increase the resource of machine parts operating under the significant dynamic loads and fretting processes.

Phase transitions in normal alkanes, such as tricosane (C23H48), tetracosane (C24H50), and pentacosane (C25H52), were studied by differential scanning calorimetry. The elimination of some procedural errors provided the possibility to obtain true values for the thermodynamic parameters of phase transitions and ascertain their nature. The comparative analysis of heat capacity jumps was performed on the basis of the theory of diffuse first-order phase transitions.

The results from ab initio quantum chemical calculations for inorganic scintillators BaBrI:Eu2+ and BaСlI:Eu2+ are presented. The calculations were performed using the density functional theory and the VASP software package. Estimates are made for the band-gap width of the crystals, and for the locations of 4f- and 5d-levels of Eu2+ ions with respect to the valence and conduction bands, respectively, and the possibility of using a new material based on BaСlI:Eu2+ as a scintillator is evaluated.

The structural changes in crystalline lamella cores of tridecanoic acid CH3(CH2)11COOH during heating in the range from the temperature T1 = 13.5°C to T2 > Tm = 41.6°C have been investigated using Fourier transform infrared spectroscopy. The behavior of the bands of rocking (in the region of 720 cm–1) and bending (in the region of 1470 cm–1) vibrations of CH2 groups in tridecanoic acid methylene segments has been analyzed. It has been shown that, in the first-order phase transition region (Ts–s ~ 36°C) within a narrow temperature range (ΔT1 ≤ 1 K), there is a gradual transformation of the initial triclinic subcell into the hexagonal subcell. The mechanism of this transition has been considered in terms of the theory of diffuse first-order phase transitions.

Nanoscale and microscale surface layers of silver on flat and wire NiTi and SiO2 substrates were produced by vacuum magnetron sputtering. The structure and the composition of samples were determined by SEM, Auger electron spectroscopy (AES), and X-ray diffractometry. The thickness and the structure of surface layers were affected by the sputtering distance and time.