Owing to transparency in the near and middle infrared ranges, nanostructures based on arsenic sulfide (As2S3) are of interest for designing integrated optics elements. We investigated laser-induced structural and photoluminescence (PL) changes in thermally evaporated and spin-coated vitreous As2S3 films. Pulsed (λ = 515 nm, τ = 300 fs) and continuous (λ = 532 nm) laser irradiation was used as a method allowing structural modification without changing the chemical composition of As2S3 films. The results of our study reveal laser-induced formation of sulfur S8 rings and polymer sulfur chains in the spin-coated films, while the local chemical composition of thermally evaporated films does not change. Laser-induced increase in the PL intensity in the range of 1.6–2.0 eV is observed, which is associated with the creation of defect states near the Urbach edge. Laser irradiation presumably increases the amount of homopolar bonds acting as radiative carrier recombination defects, while paramagnetic defects in a form of S dangling bonds do not contribute to PL.

Laser irradiation of As50Se50 thin films leads to fabrication of laser-induced periodic surface structures in them. The mutual influence of the energy and/or number of laser pulses on the evolution of the formed surface structures was shown. Birefringence and optical transmission of the inscribed in different regimes structures were measured. A possibility of using LIPSS for creating optical elements with a phase retardance of up to 50 nm per one layer, as well as a possibility of their multilayer recording were shown.

Nanocomposites based on anodic titanium oxide nanotubes with copper oxide nanoparticles were formed and their structural, optical, and electrophysical properties were studied. Defects in the structure of the samples were identified by electron paramagnetic resonance and it was shown that, as a result of copper oxide deposition, CuO nanoparticles were formed on the surface of nanotubes. It was found that the conductivity of the structure decreases by several orders of magnitude with an increase in the number of deposition cycles. It was shown that this effect could be associated with the formation of TiO2/CuO heterojunctions on the nanotube surface. It was shown for the first time that an increase in the content of copper oxide in TiO2/CuxO nanocomposites was accompanied by a decrease in conductivity and an increase in the number of defects.

Films of hafnium oxide HfOx with a thickness of about 40 nm were obtained by electron beam sputtering at di erent oxygen ow rates in the chamber. The electrophysical properties of lms in air and vacuum were studied. It is shown that the temperature dependences of lm conductivity, measured in vacuum inthe temperature range from 20 to 180 ◦C, have an activation character with an activation energy of 0.82 ±0.02 eV. It has been suggested that charge transfer in the resulting lms is determined by the activation of electrons into the conduction band from the donor level associated with oxygen vacancies. It was found that the conductivity of lms in air changes greatly with varying oxygen ow, while in vacuum the conductivity is practically independent of the oxygen ow. This indicates signi cant di erences in the surface properties of lms obtained at di erent oxygen ows in the chamber during the deposition process.

Laser-induced periodic surface structures (LIPSS) on chalcogenide vitreous semiconductors are perspective for polarization-sensitive infrared optics. We report on various LIPSS type formation on arsenic selenide thin films by femtosecond (515 $\mathbf{n m}, 300 \mathrm{fs}$) laser pulses. The LIPSS have subwavelength ($160 \pm 10$ $\mathrm{nm})$ or wavelength ($480 \pm 10 \mathrm{~nm}$) periods and form within the irradiated area independently or simultaneously, as a hierarchical structure. The formed LIPSS demonstrate birefringence with the difference between the refractive indices up to 0.1.

Нafnium oxide is currently considered one of the most promising metal-oxide materials for creating memristive structures. Memristive structures find their application in many areas of science and technology; for example, with their help, the biosimilar emulation of synapses in neuromorphic computing systems is possible. One of the important obstacles to the industrial use of memristors is the variability of resistive switching. Nonstoichiometry in memristor structure can be an important tool for controlling resistive switching. Therefore, in this work, memristors based on hafnium oxide in a metal–insulator–metal sandwich structure are synthesized by electron-beam deposition, which makes it possible to create nonstoichiometric films. The effect of resistive switching is studied depending on the material of the upper electrode and the thickness of the hafnium-oxide layer. The synthesis parameters are determined to achieve a balance between the main memristive characteristics.

Femtosecond laser irradiation of amorphous silicon films makes it possible to fabricate the laser-induced periodic surface structures which provide noticeable dichroism and birefringence of the films in the infrared range.

Pure silver as well as silver compounds have been used as antiseptics for centuries. Nowadays, the most frequently applied silver compounds are silver nanoparticles. Several studies demonstrate the ability of silver nanoparticles and silver salts to accumulate in the brain of laboratory animals as well as the ability of silver nanoparticles to influence behavioral and cognitive functions of laboratory mammals. For the first time, the influence of silver citrate on the change dynamics of behavioral and cognitive functions of laboratory mice at the daily oral exposure during 30, 60, 120, and 180 days were investigated in the present research. We observed the anxiety increase after 30 days of the exposure as well as the ability of mice to adapt to the prolonged oral exposure of silver citrate manifested in the anxiety decrease, increase of locomotor activity and the tendency of long-term contextual memory improvement at the further stages of the experiment. Increase of locomotor activity and memory improvement might be associated with the sensitivity increase and regarded as compensatory mechanism to anxiety increase. The observed phenomenon is classified as a hormetic effect. A comparison with the analogous study, which implemented polyvinylpyrrolidone coated silver nanoparticles, is carried out. It was concluded that the nanoscale impacts into the toxicity of silver compound.

Many applications, including learning neuromorphic computing systems, require the analogue or, at least, multilevel resistive switching (RS) of memristor devices. In metal–insulator–metal (MIM) structures it is often associated with the creation of a large number of conductive channels, or filaments, but in the majority of cases, especially for the vacancy mechanism of RS, the direct observation of many filaments is difficult or impossible. In this work, a model of the explicit filament conductivity distribution for a nanocomposite (NC) LiNbO 3 -based memristor, that nonetheless may be applicable to other types of MIM memristors with hopping conductivity over dangling bonds in an amorphous insulator layer, is derived from physical principles. This model, in addition to indirect evidence from magnetic and capacitance measurements, reaffirms the multifilamentary RS mechanism by the approximation of experimental data on synaptic plasticity, i.e., a change in the conductivity of a memristor by a pair of pulses applied to it. The results of this research offer opportunities to study RS in MIM structures at the macroscopic level using model filament distributions and substantiates the possibility of successfully applying the considered NC memristors as synaptic elements of neuromorphic networks.

Nanocomposites based on anodic titanium oxide nanotubes with copper oxide nanoparticles were formed and their structural, optical, and electrophysical properties were studied. Defects in the structure of the samples were identified by electron paramagnetic resonance and it was shown that, as a result of copper oxide deposition, CuO nanoparticles were formed on the surface of nanotubes. It was found that the conductivity of the structure decreases by several orders of magnitude with an increase in the number of deposition cycles. It was shown that this effect could be associated with the formation of TiO2 /CuO heterojunctions on the nanotube surface. It was shown for the first time that an increase in the content of copper oxide in TiO2/CuxO nanocomposites was accompanied by a decrease in conductivity and an increase in the number of defects.

Silver in different forms is used for medical purposes from Ancient times. It is not yet well known, which form of silver is more biocompatible and less toxic. Here we considered silver nanoparticles and silver citrate. Also, the relationships of neurotoxicity of silver compounds with ageing factor is not yet described. To assess the role of nanoform in neurotoxicity of silver and role of ageing a long-term experiment was conducted. We had four control groups of intact mice and four experimental groups which were exposed to silver nanoparticles and silver citrate for two months. Four groups of mice were introduced into the experiment since the age of five months to assess ageing factors. It was shown that the nanoform does play a certain role in neurotoxicity of silver. Silver citrate seems to be a more preferable silver compound. Ageing can be regarded as a positive factor that neutralizes toxic action of silver compounds. It may be due to the development of physiological/cognitive functions with the age as well as adaptation to unnatural content in the individual cages that is definitely stressful for mice.

The electrical properties of a complex of polyaniline with poly-2-acrylamido-2-methyl-1-propanesulfonic acid (PANI-PAMPSA) and composites based on it with the addition of silicon nanocrystals (nc-Si) ranging in size from 30 nm to 100 nm are studied in this article. It was found that the dc conductivity of PANI-PAMSA decreases with the introduction of nc-Si. Investigations of alternating current showed that the frequency dependence of the conductivity of the polymer and composites based on it obeys the Jonscher law, which indicates a significant role of the hopping mechanism of conductivity. A mechanism of PANI-PAMPSA conductivity reducing by incorporation of silicon nanocrystals is proposed. The mechanism is associated with energy distribution of localized states in the band gap of the polymer changing and is independent of the nc-Si synthesis method. Keywords: polyaniline, silicon nanoparticles, conductivity, nanocomposites.

Femtosecond laser irradiation of amorphous Ge2Sb2Te5 thin films initiates reversible phase transitions. The amorphization and crystallization of Ge2Sb2Te5 thin films were experimentally and theoretically confirmed. Electron and lattice temperatures kinetics during laser pulse duration were evaluated by two-temperature models calculations and experimental data. The dynamical changing of optical properties have been taking into account. Temperatures and cooling rates, which are necessary to initiate phase transitions by IR laser pulses with subpicosecond duration. The observed results open perspectives for improvement of Ge2Sb2Te5 nanophotonical devices.

The paste of a series of ceramic products from the Black Sea and Mediterranean regions have been studied at the National Research Centre “Kurchatov Institute” (NRC KI) and the Joint Institute for Nuclear Research (JINR) in order to identify the provenance of the ancient terracotta found in the Kerch Bay; the results are compared with the data in the literature. A classical approach was applied: the ceramic paste morphology was analyzed by optical and scanning electron microscopy, and the phase composition was studied by powder and single-crystal X-ray diffraction (XRD). The elemental composition of ceramic inclusions was determined using energy-dispersive X-ray microanalysis, and trace impurities in the ceramics were detected by neutron activation analysis (NAA). The decisive geomarkers of the terracotta ceramic paste were found to be jacobsite and titanium augite (pyroxene) admixtures. A multivariate statistical analysis of the obtained geochemical characteristics has been performed, and the likely provenance region of the terracotta ceramic raw material was determined to be the Latium region (Central Italy).

One-dimensional femtosecond laser-induced periodic surface structures (LIPSS) were formed on amorphous silicon (a-Si) films doped with phosphorus (n-a-Si) and boron (p-a-Si). The formed LIPSS ridges are directed orthogonally to the laser polarization and their period decreases from 1.1 ± 0.1 µm to 0.84 ± 0.07 µm for p-a-Si and from 1.06 ± 0.03 to 0.98 ± 0.01 for n-a-Si when the number of laser pulses per unit area increases from 30 to 120. Raman spectra analysis indicated nonuniform nanocrystallization of the irradiated films, which have a composite structure of amorphous matrix containing nanocrystalline Si phase with volume fraction decreasing with depth from ~80 to ~40% for p-a-Si and from ~20 to ~10% for n-a-Si. Observed in plane conductivity anisotropy of up to 1 order for irradiated films may be explained by the LIPSS depolarizing effect, excessive ablation of the film between LIPSS ridges, as well as anisotropic crystalline phase distribution within the film.

Chalcogenide vitreous semiconductors (ChVSs) are of both fundamental and applied interest as materials in which reversible structural transformations within the amorphous phase and phase transitions to the crystalline state can be effectively implemented and various microstructures and nanostructures can be obtained as a result of external effects. One of the most promising methods for such ChVS modifications is the pulsed-laser-irradiation technique, which is a noncontact technology of local impact and makes it possible to change the structural, optical, and electrical properties of samples in a wide range. This includes methods based on the precision formation of a surface microrelief and nanorelief, and high contrast in the conductivity and refractive index between the crystalline and amorphous phases. This work reviews key publications on the structural modification of thin films from the most widely studied binary and ternary ChVS compounds (As 2 S 3 , As 2 Se 3 , Ge 2 Sb 2 Te 5 , etc.) to show the use of irradiated samples as metasurfaces for photonic applications and promising phase-change data storage.

— A prototype for an electrokinetic generator is proposed. This device is based on polyvinyl alcohol, xanthan and poly(3,4-ethylenedioxythiophene)-polystyrene-sulfonate hydrogel. This type of electricity generation for implantable devices has been proved to be promising. The surface properties of the hydrogel in question and its volume are studied. The mechanism of conductance gradient formation in the hydrogel under the action of an electrostatic field is demonstrated and described.

A mathematical model of the biokinetics of silver nanoparticles in the mammalian organism using the example of C57Bl/6 laboratory mice with application of the concept of physiologically based pharmacokinetic (PBPK) modeling and the previously obtained by a highly precise technique of instrumental neutron activation analysis (INAA) experimental data is proposed. A numerical solution of this model was recieved. The applicability of the various assumptions was considered and justified. The obtained solution was analyzed, and the biokinetic transition-rate constants, the times of reaching the plateau and the mass content of the stable equilibrium were calculated. The numerical parameters were compared with the previously obtained parameters on the biokinetics of silver nanoparticles of the same brand. It is concluded that the proposed approach is well applicable for modeling the biokinetics of silver nanoparticles in a living organism.