Abstract Low-energy (50–200 eV) He and Ar ion irradiation of on Si/SiO2-based nanoporous materials is modeled with the use of the molecular dynamics method. The obtained results corroborate the experimentally observed effect of densification of near-surface layers of materials with small-size pores and low porosity due to the ion-induced pore collapse process. The differences in the He and Ar ion irradiation

Abstract Planar nanocomposite structures comprising poly(vinyl alcohol) films with dispersed multiwall carbon nanotubes (MWCNTs) deposited on silicon substrates and provided with aluminum contacts possess rectification properties and have asymmetric nonlinear current–voltage characteristics. Forward-biased nanocomposite structures exhibit a positive temperature coefficient of resistance (TCR) in a

Abstract The frequency and temperature dependences of the ac electrical conductivity of the MnGaInSe4 single crystals have been investigated. It has been established that, in the temperature range of 295.5–360 K at frequencies of 2 × 104–106 Hz, the electrical conductivity obeys the regularity σ ~ fS(0.1 ≤ S ≤ 1.0). It is shown that the frequency dependence of the electrical conductivity for the MnGaInSe4

Abstract The power generation of the phtovoltaic installations depends on the concentration modules’ efficiency and the Sun tracking accuracy. We have developed a system for monitoring instant tracking accuracy based on a recorder and a projecting system of solar disk imaging.

Abstract Direct experimental proof of the existence of several mechanisms of strengthening of polymer composites modified with single-walled carbon nanotubes was obtained by the method of high-resolution scanning electron microscopy.

Abstract The possibility of growing bulk (more than 7 μm thick) epitaxial semipolar AlN films on Si(001) and hybrid SiC/Si(001) substrates without cracks has been investigated. It is found that an AlN layer grown on the Si substrate is extended, whereas an AlN layer grown on the hybrid SiC/Si substrate is compressed. The limiting (critical) thickness of the semipolar AlN layer on the Si(001) substrate

Abstract The operation speed of microdisk lasers with quantum dots working at room temperature without thermal stabilization has been experimentally examined, and the widest modulation bandwidth of microdisks with various diameters has been calculated. It was shown that taking into account the effect of self-heating of a microlaser at high bias currents, which is manifested in a decrease of the ultimate

Abstract A method for growing bicrystal ZnO films using the specific features of magnetron sputtering and the orienting effect of a rhombohedral sapphire plane is proposed. It is shown that the successive application of two deposition regimes (~2 and ~16 nm/s) leads to the formation of a bicrystal film with the (110)-oriented lower sublayer and the (002)-oriented upper sublayer. Recrystallization annealing

Abstract The processes of femtosecond laser annealing of thin-film multilayer structures based on amorphous silicon and germanium produced by plasma-chemical deposition on a glass substrate have been studied. The formation of periodic structures on the surface of irradiated films has been detected by the scanning electron microscopy method. Analysis of Raman spectra has shown that amorphous germanium

Abstract The influence of impurities of light elements (C, N, and O) on the crystal–melt interface velocity in fcc metals (Ni and Ag) has been investigated by the molecular dynamics method. Dependences of the crystallization rate on the impurity concentration are obtained. It is shown that the presence of impurities reduces significantly the crystal–melt interface velocity in metals. Impurity atoms

Abstract A new method of analysis of spatiotemporal dynamics of brain activity patterns based on a continuous wavelet transform is suggested. The suggested procedure was checked using an example of brain electrical activity corresponding to motor activity planning. It has been shown that this method has pictorial capability for detection of appearance and spatial dynamics of frequency patterns.

Abstract We present the results of a transmission electron microscopy and X-ray diffractometry investigation of AlN/c-Al2O3 templates with GaN ultrathin insertions grown by plasma-assisted molecular beam epitaxy. It has been shown that AlN buffer layers with faceted surface morphology provide a greater threading dislocation density reduction than smooth layers. The filtering effect of GaN ultrathin

Abstract A new method of obtaining polycrystalline silicon is proposed which is based on indium-induced crystallization of thin films of amorphous silicon suboxide with stoichiometric coefficient 0.5 (a-SiO0.5). It is established that the use of indium in the course of a-SiO0.5 annealing allows the crystallization temperature to be reduced to 600°C, which is significantly below the temperature of solid-phase

Abstract Data on the bulk viscosity of an aqueous suspension of SiO2 nanoparticles (Ludox TM-50) have been obtained for the first time using an acoustic spectrometer. A wide range of nanoparticle mass concentrations (from 1 to 50 wt %) has been investigated. Spectra of the ultrasound attenuation coefficient and coefficients of longitudinal and dynamic viscosities have been measured. Dependences of

Abstract The results of a numerical solution of the problem of supersonic flow past an elongate blunt-fin body mounted on a plate with developing laminar boundary layer are presented. The calculations cover flow cases with the freestream Mach number equal to 6.7 and two different Reynolds numbers: Re = 1.25 × 104 and 1.56 × 104. The structure of the horseshoe vortices arising in the body leading-edge

Abstract The electroluminescence spectra and the dependences of the open circuit voltage on the photogenerated current are studied for GaAs solar cells the p–n junction of which contained various numbers of rows (r) of quantum objects based on In0.4Ga0.6As layers. For all samples, the saturation current (J0), the band gap of the quantum object (\(E_{g}^{Q}\)), and the open circuit voltage drop (ΔVoc)

Abstract A new method is proposed for determining the rate of evaporation of a group (cluster) of droplets during their gravitational sedimentation in a high-temperature gas medium. Results of experimental investigation of the evaporation of clusters of distilled-water droplets of 0.77-mm radii in air at temperatures within 650–800 K are presented. It is established that the evaporation rate significantly

Abstract Polarizability and absorption cross section of metal (Ag, Au, Cu, and Na) nanoparticles in glass far from the plasmon resonance, within the spectral interval of 1–1.6 μm, are simulated numerically. By the example of Ag nanoparticles, it is shown that the absorption cross section of nanoparticles in the telecommunication wavelength range decreases by 103 times as compared to the corresponding

Abstract The possibility of local activation of liquid boiling-up by a laser pulse at the end of a single-mode light guide is shown on the example of n-pentane superheated at 81°C relative to the liquid–vapor equilibrium temperature. An activation threshold is detected for the radiation intensity at the end of the light guide. Its value depends on the state of the light guide end, and the boiling processes

Abstract Possibilities of controlling the stability limit position in the spherical Couette flow are experimentally investigated. The rotational rate of the inner sphere periodically varies with respect to a nonzero average value, and the outer sphere remains motionless. The same as with steady-state rotation, the instability in the form of traveling azimuthal waves is caused by an increase in the

Abstract The penetration of an aluminum jet into an aluminum alloy target with a speed of 8–11 km/s is investigated. An analysis of the kinetics and parameters of introduction, and the condition of the surface of the cavity after penetration suggests that the hydrodynamic nature of penetration is violated at speeds of more than 9 km/s because of fusion of interacting metals. The results of the study

Abstract A nanorelief forming on a copper surface under oblique irradiation with cluster ions has been examined at different irradiation doses and target temperatures. This nanorelief has been found to evolve into an ordered undulating structure. It has been demonstrated that the initial roughness is smoothed out at higher target temperatures. The mechanisms of formation of the surface topography have

Abstract The method of molecular-beam epitaxy was used to fabricate an elastically balanced heterostructure of a quantum-cascade laser for the spectral range of 4.6 μm based on a heteropair of solid alloys, In0.67Ga0.33As/In0.36Al0.64As, and indium phosphide layers serving as waveguide cladding layers. An X-ray diffraction analysis demonstrated the high uniformity of the composition and thickness of

Abstract The magnetoelectric (ME) effect in a planar amorphous ferromagnet–piezoelectric lead zirconate titanate (PZT) composite structure can be effectively excited by passing alternating current through the magnetic layer. The absence of demagnetizing (stray) field and the orientation of the exciting magnetic field perpendicular to the constant field allow this structure to generate the even harmonics

Abstract Composite films based on CH3NH3PbI3 organometallic perovskite and mixed cellulose ester (CE) were studied using terahertz (THz) spectroscopy in the time domain. It is established that the introduction of CE into CH3NH3PbI3 precursor significantly modifies the parameters of perovskite in the THz range and improves stability of the composite films. In particular, CE addition to the perovskite

Abstract— The effect of mechanical vibration on the optical transmission of the infrared fibers of the AgCl0.25Br0.75 and AgCl0.5Br0.5 compositions for 30 h has been studied. It has been shown that the vibration causes a decrease in the transmission of the fibers. The selective nature of the transmission of the infrared fibers in the wavelength ranges 2.0–4.0 and 6.0–9.0 μm has been found.

Abstract The impurity composition of multi-sector plates of nitrogen and boron-containing synthetic HPHT diamonds has been investigated by laser-induced breakdown spectroscopy. It is shown that a comparative analysis of the intensities of the characteristic atomic and molecular bands in the plasma emission spectrum during laser-induced modification of the surface of the samples makes it possible to

Abstract Experimental results of studying the solid-phase transformations in Se/Cu nanosized film structures fabricated by vacuum thermal evaporation method are presented. It is first shown that, varying the proportion of copper and selenium atoms (N) in the sample, it is possible to control the phase composition of the synthesized films. The relation is established between N and the phase composition

Abstract A technique for growing thin graphite films on a dielectric substrate by annealing the Al2O3(0001)/Ni(111)/ta-C structure has been optimized. This technique is based on catalytic decomposition of hydrocarbons on the surface of a single-crystal catalyst metal film on a dielectric substrate and subsequent diffusion and crystallization of carbon between the metal film and the substrate. A thin

Abstract A theoretical model of photoacoustic response signal formation from laser-irradiated metal membranes is proposed with allowance for the excitation of defect states. Theoretical results obtained for 197-μm-thick aluminum membranes in a frequency range from 20 Hz to 7 kHz are compared to experimental data for membranes excited by laser radiation at a 660-nm wavelength. The proposed theoretical

Abstract The structure of dentin is characterized by the presence of microchannels—dentinal tubules (DTs) threading through the matrix composed of collagen fibris and hydroxyapatite nanocrystals. The influence of DTs on the resistance of dentin to cracking has been studied on samples prepared from human molar teeth. The samples were subjected to uniaxial compression until the onset of cracking and

Abstract We have experimentally studied the process of microexplosive fragmentation of two-component (diesel fuel–water) liquid droplets heated in a high-temperature gas medium. The experiment involved a group of 10–30 droplets falling down in a tubular muffle furnace. The delay times of microexplosion were studied and it was established that integral characteristics of the process significantly depend

Abstract A quantum-mechanical approach to analysis of the interaction between electromagnetic radiation and ultrathin conducting films in the frequency range of 1–200 GHz is proposed. It is shown that, at film thicknesses smaller than 10 nm, it is necessary to take into account the symmetry of the conductor atomic lattice, the break of which can lead to an increase in the energy gap between the valence

Abstract Film structures of porous graphene have been produced by irradiating a polyimide film with focused radiation of a continuous CO2 laser. The generation of nanosecond photocurrent pulses induced by nanosecond laser pulses in a wide wavelength range has been observed in the obtained structures. It has been demonstrated that the photocurrent increases linearly with pulsed laser power and is an

Abstracts The field-emission characteristics of cathode arrays based on nanocomposite diamond–graphite film structures with a reinforcing tunnel-thin diamond coating are investigated. These field emission characteristics are not related to the morphology of the emitting surface and cannot be explained in terms of the Fowler–Nordheim model. The effect of the thickness of the diamond coating on the field-emission

Abstract The influence of the channel shape in a finned (vertical) field-effect transistor (FinFET) on the amplitude of random telegraph noise (RTN) induced by single interface trapped charge has been simulated for the transistors with rectangular and trapezoidal fin cross sections. It is established that, in a subthreshold region of gate voltages, a single charge trapped at the fin top induces RTN

Abstract Line tension is calculated for a simple model of a surface nanobubble formed on a smooth hydrophobic substrate. It is shown that, with an increase in the contact angle at a certain critical value, the surface tension changes sign from positive to negative. This means that the surface tension stretches the nanobubble, increasing its radius of curvature and thereby stabilizing it.

Abstract An ensemble of a sequentially arranged Wien linear velocity filter (WLF) and an energy analyzer with a retarding potential (retarding field analyzer, RFA) allowed measuring the ion spectra of a multicomponent plasma flow by energy, mass, and charge. The ideas and test results of two versions of the analyzer—WLF–RFA and RFA–WLF—are described.

Abstract Two discharge burning modes (“needle” and “bell”) have been experimentally studied for a Hall thruster with a nominal power of 1.5 kW. The integral parameters of the thruster operation (thrust and specific thrust impulse) are measured in the two stable discharge burning modes. Investigations have been carried out for discharge voltages of 300–800 V and gas flow rates of 1.5–3 mg/s. The results

Abstract The influence of operating modes on the response of ammonia sensors based on tin dioxide films has been studied. Samples have been obtained as a result of high-frequency magnetron sputtering of a SnO2:Sb target on sapphire substrates with predeposited Pt electrodes and a heater. Varying the heating cycle duration and reducing the cooling cycle temperature may increase the response by one or

Abstract New Al/SiC heteroparticles are investigated experimentally and theoretically. A composite material based on Al and SiC is predicted to exhibit a markedly higher tensile strength than pure Al due to the robust interface between Al and SiC. The theoretical predictions receive experimental confirmation. Specifically, incorporation of nano-SiC into the aluminum matrix to a level of 10 wt % is

Abstract The role of clustered particles in the formation of a secondary flow (“wake”) upon the outflow of gas into a rarefied medium in condensation modes is found out. The boundaries of the “wake” are found by comparing the spectral and photometric measurements. Possible mechanisms of the initiation of its glow are considered. The role of the energy exchange of clusters with background gas in the

Abstract AlN/c-sapphire templates grown by plasma-activated molecular beam epitaxy have been studied using multicrystal X-ray diffractometry and a multi-beam optical stress meter system. Studies of the seed and buffer layers grown at different ratios of Al and N* growth flows and substrate temperatures have shown that templates with small tensile elastic stresses (<0.5 GPa) and densities of screw and

Abstract The kinetics of nucleus growth from a parent nanophase medium with a limited stock of material has been theoretically studied in the presence of possible growth arrest caused by destruction of the source of supersaturation. This regime is characteristic of the island growth of GaAs nanowires (NWs) from a Ga nanodroplet via the vapor–liquid–solid (VLS) mechanism as observed during in situ diagnostics

Abstract A new miniature design of a highly selective lowpass filter based on a suspended substrate with a two-sided stripline pattern has been developed. The filter frequency response slope (cutoff attenuation rate) and stopband attenuation depth are determined by transmission zeros, the number of which is equal to the filter order. An experimental prototype of a fifth-order lowpass filter on 0.5-mm-thick

Abstract An ablation of a thin layer of surface contamination of the target that self-recovers after each pulse of a powerful ion beam has been used to control ion fluences. Using a time-of-flight optical spectrometer, the average speeds of the lightest components of the ablative plasma, which are hydrogen and carbon, have been measured. and the ion fluence has been determined by their difference.

Abstract The mode of generation of picosecond optical pulses in the spectral range near 1064 nm by semiconductor lasers with distributed feedback and active region based on an InGaAs/GaAs quantum well has been studied. In the gain-modulation mode, the width of laser pulses decreases from 150 to 35 ps as the temperature increases from 5 to 50°C. It was demonstrated that there is a temperature range

Abstract The contribution of residual atmosphere gases to the flux of collectively accelerated protons in a Luce diode has been determined by comparing the number of protons generated by anodes made of polyethylene and pyrolytic boron nitride. Radioactivation diagnostics based on the nuclear reactions 10B(p, α)7Be and 12C(p, γ)13N has been used to determine the mean number of protons per pulse and

Abstract Nonlinear optical microscopy techniques have been used to study thin films of single-phase (perovskite) and two-phase (perovskite–pyrochlore) lead zirconate titanate (PZT) deposited on Pt/TiO2/SiO2/Si by means of radio-frequency magnetron sputtering at various target–substrate distances (D = 30–70 mm). Results revealed inhomogeneous distribution of second-harmonic generation in spherulitic

Abstract Epitaxial aluminum nitride (AlN) layers on Si(111) substrates have been grown by sequential application of several techniques including reactive magnetron sputter deposition to a thickness of 20 nm, metalorganic vapor-phase epitaxy (MOVPE) to a total thickness of 450 nm, and hydride vapor-phase epitaxy (HVPE) to a final thickness of 2 μm. Synthesis of AlN layers by this combined method provides

Abstract Coatings are fabricated using plasma-ion sputtering and codeposition of ultradispersed Ta and Cd particles and Nb- and Mo-doped W and Cd particles. The fabricated coatings consist of a mixture of crystallized cadmium and the amorphized refractory metals. Subjecting the coatings to thermal annealing in vacuum at 800°C for 1 h results in complete evaporation of cadmium from the coatings and

Abstract—A new method is proposed for studying relaxation and transient processes in ferroelectric ceramics under the influence of a constant electric field. Precision measurements of the time dependences of the complex permittivity of ferroelectric ceramics in the region of weak electric fields were carried out using the method of impedance spectroscopy. A comparative analysis of various methods for

Abstract We report results of the first investigation of dusty plasma formed in glow discharge in the region of a strongly inhomogeneous magnetic field with a field gradient estimated at 2 × 103 G/cm, where a stable magnetic trap has been found. Geometric characteristics of the dusty plasma structure were determined, and the angular velocity of plasma rotation in several sections perpendicular to the

Abstract The influence of dynamic preload on the fatigue endurance limit of AMg6 alloy has been experimentally studied in a range of 109 loading cycles. It is established that prestraining up to 10% deformation at 103 s–1 rate leads to a 22% decrease in the fatigue endurance limit. A mathematical model is proposed that can adequately predict fatigue fracture, including that after preload.

Abstract The effect of induced mechanical activation of radio-frequency superradiance in a parametric mode under the action of an external rheological explosion at high pressure on a paramagnetic composite—a system of crossed spins based on binuclear complexes Co (QH)2–O–Co(QH)2 or Mn(QH)2–O–Mn(QH)2 (QH is a ligand based on 3,6-di-tert-butylpyrocatechol) in a polystyrene matrix—is found. Possible methods

Abstract In this paper, we examine the issues of the formation and propagation of melted zones during electric explosion of thin aluminum films on the oxidized silicon surface. A difference in the formation and propagation mechanisms of melted zones on the surface during the passage of a current pulse and after it was switched off is found. After the current pulse is switched off, the migration of

Abstract The mechanisms of current transport through indium antimonide quantum dots (QDs) have been examined by analyzing normalized differential tunneling current–voltage characteristics. Electron tunneling with the discrete spectrum of QDs taken into account has been studied. The positions of the first three levels of their electronic spectrum have been estimated. It has been demonstrated that the

Abstract Results of designing and studying a prototype of an active element on copper bromide vapors with continuous control of the energy of each radiation pulse are presented. It is distinct feature in featuring implementation of the above mode for a gas-discharge tube with a large volume (above 1.5 L) and formation of the radiation by an unstable cavity. In doing this, a hydrogen-containing addition

Abstract In the framework of the model of cold hydrodynamics, acceleration of the flow of dusty plasma in azimuthal electric and radial magnetic fields has been studied. The obtained results show that there are conditions under which macroscopic particles are captured and accelerated by the plasma flow.

Abstract Single-mode lasing of quantum-cascade lasers with a distributed Bragg reflector formed by ion-beam etching in layers of the upper waveguide cladding is demonstrated. The active region is formed based on an In0.53Ga0.47As/Al0.48In0.52As solid-alloy heteropair with two-phonon depletion of the lower level in the cascade. Single-mode lasing at a temperature of 280 K corresponds to the emission