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A comparative analysis of the studies on the influence of the textile structure of reinforcing fabric on the physicomechanical and sorption characteristics of anion-exchange systems as a component of the “Polikon” mosaic materials is presented in this study. This study shows the promise of using polyester fibers as a reinforcing fiber base for the production of Polikon A membrane materials. The morphology, moisture capacity, static exchange capacity, and physical and mechanical characteristics of anion-exchange membrane systems were investigated. A modification of Polikon A anion-exchange matrices on lavsan fabric by oxidized ultrafine particles of silicon, iron and nickel is proposed.

The use of reverse polarization during the electrodeposition of the Zn–Ni–Co alloy made it possible to increase the amount of alloying components, Ni and Co, in the composition of the deposit. It is established that the inclusion of cobalt in the composition of the Zn–Ni coating and the use of the reverse electrolysis mode contribute to the production of finer crystalline coatings with corrosion resistance exceeding this characteristic of the chromated zinc coating.

The possibility of using nonwoven fabric made of a viscose fiber to produce Polykon mosaic materials is demonstrated for the first time in this work. The materials are obtained by polycondensation filling of polymer composites, namely, by the synthesis and curing of a weakly basic anionite and a strongly acidic sulfo cationite on the surface and in the structure of a nonwoven material made of viscose fiber. The techniques and technological parameters of the production processes are discussed. The “transition from the cationite to the anionite” process scheme in combination with the optimum times of curing is selected. The effect of the composition of the “compound” on the properties of mosaic materials is investigated. A comparative analysis of the obtained materials with Polykon mosaic materials based on a novolac phenol formaldehyde fibrous matrix is performed. The thermal stability and physical and mechanical properties of the mosaic membranes are studied.

Background and Objectives: Porous silicon nanowires (SiNP) obtained by the method of metal stimulated chemical etching (EE method) are of great interest. The physical properties of this material depend significantly on the morphology of the nanostructures and their sizes. Given in the literature data on the effect of small doses of ionizing radiation on metals and alloys and the effect of irradiation on the properties of porous silicon and SiNP, makes sense to modify not only the substrate, but also the SiNP layer during its formation by irradiation. A change in the morphology of the formed layers with increasing in situ irradiation within small doses can affect the properties of SiNP. In the literature known to us, this issue is not considered. This work presents studies of the total reflection, Raman scattering, and photoluminescence of SiNP upon irradiation with γ-rays directly in the production process (in situ). Materials and Methods: The formation of nanoporous silicon structures was performed on non-irradiated and irradiated with small doses of gamma-quanta substrates. The substrates were processed by the Saratov State University’s betatron electron brake accelerator at a maximum energy of Eymax ~ 25 MeV. The radiation dose was 30 and 40 kR. A layer of porous SiNP nanosilicon was formed on irradiated and non-irradiated substrates. Samples were obtained by water-based non-electric etching or metal-stimulated chemical etching. The method of chemical etching EE is based on the replacement of silicon when reducing Ag+ → Agо on the surface of the silicon substrate using Ag in an aqueous solution of AgNO3. Porous silicon structures were formed by a two-stage method on irradiated gamma-quanta and non-irradiated p-type silicon substrates with a resistivity of 4.5 Ω cm, oriented in the plane . The substrate was lowered into an aqueous solution of 0.01 M AgNO3 and 5M HF for 60 s., then was etched in an aqueous solution of 5M HF, 0.5 M H2O2 for 20, 40 and 60 minutes, respectively. The studied nanoporous structures were obtained on irradiated and non-irradiated substrates without irradiation and when irradiated in situ with inhibitory gamma radiation of the medical linear electron accelerator Varian Unique of State Health Institution “Regional Clinical Oncology Dispensary” at an electron energy of 6 MeV. After receiving the samples, they were purified in concentrated nitric acid for an hour. The structural properties of SiNP were studied using measurements on an analytical complex based on the Mira 2 LMU scanning electron microscope, as well as the DRON-4 diffractometer using an x-ray tube with a copper anode (Cu-Ka). Full reflection spectra in the range of 500–1100 nm were obtained using a LOMO SF-56 spectrophotometer equipped with a special integrating set-top box. Raman spectra were recorded using a Renishaw inVia spectrometer. Results: The samples under study are quasiordered ensembles of silicon nanowires oriented almost normal to the substrate. The thickness of the SiNP layer is of the order of 1–8 μm, depending on the preparation conditions, and the diameter of the nanowires was 30–400 nm. In all SiNP samples, a decrease in total reflection was observed in the wavelength range of 400–1000 nm as compared to a single-crystal substrate, which is associated with light scattering on an inhomogeneous structural surface. At the initial stage of the process, the defective state of the substrate was decisive; microstresses on the substrate disappear when it is irradiated. For SiNP samples, total reflection increased with increasing radiation dose over time (from 0 to 24 kR) due to improved surface quality, reduced scattering, and a change in layer thickness. In addition, in situ monitoring of SiNP samples indicates the influence of not only the radiation dose of the formed layer on the reflection value, but also the dose of preliminary irradiation of the substrate. Raman spectra were studied to determine the effect of gamma-irradiation on the properties of porous silicon – SiNP in situ. The intensity of the main peak of Raman scattering of SiNP samples obtained on non-irradiated and irradiated substrates is significantly higher compared to the intensity of the main peak characteristic of single-crystal silicon. Against the background of the high Raman signal, light scattering from particles with broken bonds does not appear and basically gives a maximum – a peak P1 of the order of 519.5 cm-1, slightly shifted to the low-frequency region relative to the maximum of peak P1 of a single-crystal silicon substrate 520 cm-1. An increase in the irradiation dose of the substrate leads to an increase in the intensity of the main Raman peak. Studies of Raman spectroscopy of nanostructured porous silicon-silver layers have revealed the effect of surface giant signal amplification (SERS). The maximum silver content is below the surface of the samples. The depth of the silver-enriched layer is about 250– 400 nm. The photoluminescence peak of SiNP samples formed on irradiated and non- irradiated substrates shifts to the shortwavelength region as the radiation dose increases. The shift is much more dependent on the dose of the substrate than on the irradiation of the layer. The calculated nanocrystallite size by λmax was about 2 nm. Conclusion: The results of an experimental study of the optical properties of porous Si structures obtained by metal-stimulated chemical etching when irradiated with small doses of gamma-quanta directly during in situ formation are presented. In situ monitoring of samples indicates the influence not only of the radiation dose of the resulting layer on the value of total reflection, but also the dose of pre-irradiation of the substrate. Studies of Raman spectroscopy of nanostructured layers of “porous silicon-silver” revealed the effect of surface giant signal amplification in samples. There is a shift in the wavelength of the maximum photoluminescence from 600 nm to 750 nm when the irradiation of the substrate changes from 0 to 40 kR at the same radiation dose of the layer.

Several aspects of the synthesis and formation of a sulfonated cation-exchange matrix on the surface and in the structure of novolac phenol—formaldehyde fiber with nanodisperse iron and nickel oxides added to the monomer composition were examined.

A unique method for producing Polikon cation–anion exchange mosaic materials has been proposed. The materials were prepared by the polycondensation filling of polymer composites and via synthesis and curing of a weakly basic anion exchanger and a strongly acidic sulfonated cation exchanger on the surface and in the structure of a fibrous novolac phenol–formaldehyde matrix. Molecular models that characterize the chemical composition of the developed composites are given. The effect of the composition that facilitates the formation of a material with stable performance characteristics has been studied. The cause-and-effect relationships of the structural, physicochemical, and operational properties of the heterogeneous cation–anion-exchange mosaic materials Polikon under thermomechanical action at the stage of polymer matrix curing were investigated. Empirical equations that refine these relationships were obtained. The morphology and internal structure of the test heterogeneous membranes were characterized by scanning electron microscopy and energy-dispersive elemental analysis. The viscoelastic properties of the samples were studied by dynamic thermomechanical analysis.

—The effect of low-dose γ radiation on the mechanisms of low-frequency conductivity of mesoporous silicon has been studied. It has been shown that γ irradiation preserves the hopping character of conductivity at a change of the frequency of phonon lattice vibrations, a decrease in the size of the hop, and a shift of the level of the capture of traps to the Fermi level in the band gap, which makes the structure with mesoporous silicon irradiated by γ radiation promising for the creation of multifunctional resistive and capacitive devices.

In this work, we solve the problem of predicting the dielectric constant of silicon-based nanocomposites using machine learning methods. Mathematical models and programs have been developed to predict the electrophysical properties of new materials, as well as to select the optimal composition. The results obtained will be useful for faster and cheaper creation of new functional composites.

This paper discusses promising designs for the heat sink of a laser diode array, which make it possible to controllably control the product life and provide the most uniform temperature aging of materials when it becomes necessary to increase the radiation power.

The results of a study of the optical properties of porous silicon nanostructures obtained by metal-assisted chemical etching of γ-quanta irradiated with low doses during their formation are discussed. The total reflection from the obtained samples depends not only on the irradiation dose of the forming layer, but also on the dose of preliminary irradiation of the initial silicon wafer by in situ control. By studying the Raman spectra of the samples, it was confirmed that changes in the spectra take place both due to the effect of small doses of γ-quanta on the initial silicon wafers and due to the in situ effect of gamma radiation on the forming SiNWs. We observed a shift in the wavelength of the photoluminescence maximum from 600 nm to 750 nm with a change in the irradiation of the initial silicon wafer from 0 to 40 kR at the same dose of irradiation of the forming porous layer.

Raman scattering have been measured to study optical and structural properties of porous GaAs layers obtained by anodic etching. The Raman spectra are described and compared with the Raman spectra of single-crystal GaAs. The photoluminescence (PL) spectra were calculated using the Raman spectral regions with the presence of photoluminescence. The obtained PL spectra were used to quantitatively estimate the size of nanocrystallites in the porous layer. Analysis of the data allowed us to conclude that the quantum size effect is present in porous GaAs nanocrystallites.

The processes of thermal oxidation and carbonization of copolyamide benzimidazole (CPB) fibers were investigated, structural and chemical transformations were characterized by thermogravimetry, IR spectroscopy, elemental analysis, atomic force microscopy, and physicomechanical and electrophysical properties. Fiber hardening was found to occur on treatment at low-temperatures in air. It was shown that the preliminary oxidation of CPB fibers has practically no effect on the carbonization of the polymer. Impedance studies have confirmed that structural chemical modification leads to a decrease in the active resistance of the polymer fiber.

Photoluminescent macroporous silicon is studied for tumor imaging application. Gamma-radiation is used for modification of morphology of pores and their size. It is shown by Raman and photoluminescence study that after the irradiation of gamma rays new nanocrystallites of smaller diameter in comparison to the initial porous silicon appeared.

The possibility of modifying the photoluminescence properties of porous silicon by irradiation with low doses of γ photons from a 226Ra radioisotope source and bremsstrahlung is demonstrated. The position of the longest photoluminescence wavelength tends to shift to the short-wavelength region of the spectrum. The emission efficiency increases upon irradiation of both the substrate and the layer formed.

The thermomechanical stability of the anion–cation exchange matrix “Polikon AC” on viscose nonwoven materials is investigated. In this work, a molecular model of a solvation environment for experimentally obtained “Polikon AC” mosaic membranes is refined. Mosaic membranes on a viscose fiber base were fabricated by the method of polycondensation filling. The temperature dependence of deformation was investigated for dry and wet anion and cation exchange membrane components at a constant tensile load of 1.5 N and a heating rate of 8 °C/min. The effect of moisture content on the deformation of anionite and cationite fragments under a constant external tensile load of 1.5 and 3 N in a temperature range up to 100 °C was studied.

A general methodology of research is presented, and the evolution of ideas about the material Polikon is discussed. The optimal monomer ratio, used for preparing the impregnating composition, to promote the formation of the material with high performance characteristics has been revealed. Empirical equations relating the static exchange capacity to the fibrous matrix/impregnating composition ratio, compacting pressure, curing time, and fiber nature have been derived.

The influence of low doses of γ rays on the capacitive properties of structures based on mesoporous silicon has been investigated. The concentration distribution of dangling charged bonds over the layer depth, which changes under irradiation, has been found using the capacitance–voltage characteristics at different frequencies of the test signal. It is shown that the concentration and relaxation time of surface charged states in a structure with a mesoporous silicon layer decrease under γ irradiation, which makes the material promising for devices with controlled reactance (varactors) that are resistant to γ irradiation.

The effect of low exposure doses (5–40 kR) of gamma radiation on the electrical properties of structures based on a mesoporous silicon (SiMP) layer is investigated. It is demonstrated that the conductivity of the SiMP layer increases, the Fermi level shifts, and the trap density changes in gamma-irradiated Al/SiMP/p-Si/Al structures. Long-term stable switched-state memory in the region of the I–V curve hysteresis is revealed. This effect is controlled by the irradiation dose.

The study of the formation of silicon nanowhiskers by the method of non-current two-step etching is presented in this paper. Silicon nanowhiskers were obtained on unirradiated single-crystal silicon and on irradiated γ-quantum substrates. At an etching time of 20 to 50 minutes, the length of nanowhiskers is independent of the radiation dose (with a diameter of 70 to 140 nm), however, with increasing etching time, the length of the nanowhiskers increases sharply with increasing radiation dose. The optical and structural properties of silicon nanowhiskers under the influence of gamma irradiation are discussed.

The nanocomposite - conglomerate grains of semiconductors was explored. An equivalent replacement scheme was developed, which is a parallel-sequential grid connected linear and nonlinear elements. Current-voltage characteristics of a semiconductor conglomerate were obtained. Mathematical modeling current-voltage characteristics for a nanocomposite based on ceramics and semiconductor grains of zinc oxide. The obtained results show that the geometric parameters, such as the number of layers and the width of the sample, affect the current-voltage characteristics of the nanocomposite, the work point of the current-voltage characteristics shifts.

Experimental studies were carried out by two different sources of gamma quanta. Samples were irradiated gamma - quantum radioisotope source 226Ra and electron accelerator braking gamma radiation - betatron Saratov state university. The form of the diffractograms shows the high crystallinity of the samples under study. The effect of gamma rays of radium led to a slight shift of the maximum of the reflex relative to the angle 2θ=29.18° to the left and a decrease in its width. The structure of the samples irradiated with γ-quanta of the bremsstrahlung of the betatron, according to the measurements, has undergone more significant and unexpected changes.

On the basis of special software and digital methods, a hardware-software system has been developed that allows one to investigate the dielectric constant of nanocomposites. A traditional measuring system consisting of a set of specialized measuring instruments - information display means, is replaced by an integrated digital information and measuring system consisting of a converter unit, a personal computer with special software. The possibility of using a set of programs and digital methods in a full-scale experiment on the study of electrical characteristics is shown.

The potential for fabricating Polycon ion-exchange membranes based on chemical fibers and ionexchange matrices was studied. The fibrous filler was viscose fiber. Sulfonated cation-exchange and polyfunctional mixed-basicity anion-exchange lateral sections were deposited on the fibrous base. The main techniques and process parameters for preparing mosaic membranes were developed. The effect of curing processes on the structural and physicomechanical parameters was studied.

The paper presents the method of tunneling microscopy study of mass transfer in the structure containing nanometer layer AgI. The possibility of using of interface Ag-AgI-insulator-metal as a resistive switching memory with charge ∼5 pC and multiplicity of resistance ∼20 is shown.

Electrical and photoelectric properties of porous silicon with introduced silver nanoparticles have been studied. It is shown that in the “dark–light–dark” operation mode, an abrupt jump of the dark current is observed upon illumination (with light spectrally close to sunlight), which is three to five times the initial dark current and the photocurrent. The voltages at which these abrupt changes in current are observed correspond to the range of existence of traps formed when the starting mesoporous silicon is obtained. It was found that the increased value of the dark current exhibits a long-term memory effect. The “current jump” can be attributed to the maximum capture of the generated photocarriers by traps, followed by their release in an electric field after the illumination.

Probable spatial fragments modeling polyacrylonitrile fiber, the monomerized composition, and Polikon K—Polikon K1a material were developed. The Polikon K1a model identified the most probable reaction site of the polyacrylonitrile copolymer fiber with reactive CH3– groups of the polymer matrix, namely, the reaction with a C≡N group via cleavage of one bond and formation of a methylene bridge. IR transmission spectra in the range 4000-200 cm–1 were calculated for the obtained models. Experimental and calculated IR spectra were compared in the range 2000-400 cm–1. The calculated IR spectrum correlated with the experimental spectrum of Polikon K.

A comparative study of the optical and morphological properties of different modifications of silicon and their dissolution upon interaction with distilled water and a biologically active medium is carried out. For the biologically active medium, nonpathogenic baker’s yeast (Saccharomycetes cereviseae) is chosen. It is shown that water and the biologically active medium interact with the surface of the materials and, thus, change the surface morphology and produce a modified layer. The strengths of the effect upon nanoparticles, nanoparticle-based structures (porous silicon), and single-crystal silicon doped with different types of impurities to different levels are different.

It was shown that the complex research of iron nanoparticles properties by different methods, supplemented each other, permit to receive the data about the interior sizes of nanoparticles, a number of physical properties of particles, their dependence on frequency and changes produced by various influences. It was found that the conductivity of nanoparticles changed under the square depen-dence σ = σoω2

A preliminary conformational analysis of chemical reactions of functional groups in Polikon K was performed. Five mechanisms for chemical reactions of polyacrylonitrile fibers with amines were identified. The level of steric energy was estimated preliminarily as a characteristic of the heterostructure strain. A general scheme for calculating the potential energy of the Polikon K molecular system was based on Allinger force field concepts.

The photoelectric and photovoltaic properties of structures based on mesoporous silicon passivated with iron (SiMP:Fe) are studied. It is shown that these properties ambiguously depend on the iron concentration. In the case of a sample with space-charge-limited currents (SCLCs), the charge-transport mechanism in the Al-SiMP:Fe-p-Si-Al heterostructure changes under illumination from the SCLC type to the barrier type. Passivation with 0.1–0.2 at % iron stabilizes not only the electrical, but also the photoelectric and photovoltaic properties of the structures. A further increase in the Fe concentration gives rise to new traps caused by the appearance of iron and silicon oxides, which leads to instability of the properties. The structures exhibit high sensitivity under low-level illumination. The open-circuit voltage is 16 mV under AM-1 irradiation (∼2 mW/cm2).

The current-voltage and capacitance-voltage characteristics of structures based on mesoporous silicon, obtained by electroless etching with passivation by iron, (SiMP:Fe) are investigated. It is shown that the conductivity and barriers in Al-SiMP:Fe-p-Si-Al heterostructures ambiguously depend on the Fe concentration. Passivation by iron changes not only the conductivity of the SiMP:Fe layer but also the character of carrier transport at low frequencies. At an iron concentration of ∼1 at % tunneling transport through barriers becomes dominant in comparison with jumps over dangling bonds. Passivation of the SiMP layer by iron stabilizes the SiMP electrical properties (which is confirmed by the values of the trap concentrations estimated from the current-voltage characteristic) of structures subjected to long-term storage. This is likely to be related to the interaction between iron ions and the silicon surface with the formation of oxides.

The possibilities of modifying the IR spectra of porous silicon under irradiation by low doses of gamma — quanta of radioisotope source of 226Ra and bremsstrahlung radiation are investigated.

A composite medium layered fractal structure was examined. Mathematical models of complex composite structures were developed using the effective medium theory. Algorithms and program complex, allowing exploring layered fractal structure designed. To describe the study of qualitative properties of composite media techniques are used fractal theory. The application of this approach through the conditions Takens criterion. The sensitivity of the fractal dimension of the elements of composite media structure to changes in their quality parameters calculated by the method Bolshakov — Dubrovin.

Results are presented from a study of “Polikon” fibrous chemisorbent composites. The composites, made by the method of polycondensation filling, are obtained from polyacrylonitrile fibers with a low content of ultradispersed additives. The excellent service properties of the materials allow them to be used as fillers for the desalination channels of electrodialysis units.

The possibility of modifying a sulfonated phenol cation-exchange matrix of chemosorptive Polikon K composite fibers was examined. The fibers consisted of cross-linked, rigid, and relatively brittle polymers and were modified by ultradispersed Fe and Ni additives in order to form structures with accessible ionizable groups that were more resistant to cracking.

The electrical and photoelectric properties of nanostructures with porous silicon layers obtained by electroless etching of silicon have been investigated. It is found that the photoelectric and photovoltaic properties of these structures depend on their morphology and are determined by not only the properties of the modified layer, but also the presence of possible barriers in the layered porous silicon. The ratio of the photoconductivity to the dark conductivity reached 102−5 × 102. An open-circuit voltage V oc was detected that amounted to ∼250 mV at an incident light power close to AM-1 (∼100 mW/cm2). In this case, the density of short-circuit current I sc was about 20 μA/cm2.

The electron-transport processes in structures with oxidized porous silicon (OPS) are investigated during adsorption and desorption of polar molecules from atmosphere when the air pressure varies. It is shown that the cause of the existence of the open-circuit voltage in Pd-OPS-p+-Si-Al structures in the initial state is the surface-charge change on the Pd-OPS interface due to the polar-molecule adsorption from atmospheric air. The desorption of atmospheric-air molecules leads to a change in the current-voltage characteristics of structures, growth of the metal-OPS barrier in samples with the Schottky barrier, and initiation of current instabilities. The nanocrystalline nature of OPS manifests itself in the charge-carrier localization in quantum dots (QDs) during desorption in samples with space-charge-limited currents.

The effect of illumination and adsorption of polar molecules on the properties of structures based on oxidized porous silicon has been investigated. The specific features of these structures are fluctuations and a change in the sign of open-circuit voltage under the influence of long-term photoexcitation, time-related instabilities of the current in media with a high content of hydrogen sulfide, long periods of photocurrent decay after switching off the illumination, and the occurrence of negative photoconductivity in structures with space-charge-limited currents. The results obtained are explained by the presence of multiply charged traps of different types in oxidized porous silicon, their charge exchange, and the tunneling of charge carriers between silicon nanocrystallites.

A noncontact method for the express-testing of the relative deformation of lattice parameter (Δa/a ) of semiinsulating GaAs has been developed. This method is based on measuring the reflected radiation in band-to-band regions L3v - L1c and X5v - X3c. The suggested method ensures a resolution of 4 × 10-5 in determining (Δa/a ) and has a measurement accuracy of about 0.5%.

Memristor structures based on tunnel-thin organic dielectric and porous silicon layers are investigated.

Arc plasma synthesis of iron nanoparticles: morphological, dielectric and magnetic characterization are discussed.