An anodic alumina membrane (AAM) is produced using two-step anodizing by using various types of acidic electrolytes, such as sulfuric acid, phosphoric acid and oxalic acid. Holes are characterized by hexagonal structure with diameters ranging from 40 to 420 nm. Heat and chemical stability also regular formed holes are made the membranes appropriate for using in gas separating process, drug delivery and applicant for fuel cell membrane. Detaching of membrane from the aluminum base is the most important stage of the membrane production process. In this research, initially, the aluminum base layer was removed with the use of CuSO₄ and HCl. In secondary step, barrier layer at the end of the holes were removed with phosphoric acid solution. The aim of this work is to analyze the effect of time on the barrier layer removal process.

The dielectric properties of a paramagnetic terbium-containing liquid crystal have been studied. The magnitude and the sign of the dielectric of the liquid crystalline complex have been determined. The relaxation processes (modes) characterizing the dispersion of the principal values of the sample’s dielectric permittivity has been studied. The relaxation times, activation energy and the dipole moment of the complex could be evaluated.

The subject of this study is the thermoelectric efficiency (Z) and the thermoelectric parameter (ZT) of carbon nanocomposites, namely, the structures consisting of graphite-like (gr) and diamond-like (d) regions made of sp² and sp³ hybridized carbon atoms, respectively. The impact of heat transfer across the boundary between sp² and sp³ areas is analyzed for the first time. It is shown that the interfacial thermal resistance (Kapitza resistance) is not lower than the thermal resistance in the macroscopic gr region. The influence of various factors on the Kapitza resistance is analyzed. The value of ZT ≈ 3.5 at room temperature, taking into account the interfacial thermal resistance, is significantly higher than it would be in gr films (ZT ≈ 0.75).

The calculation of minimum energy paths for transitions such as atomic and/or spin rearrangements is an important task in many contexts and can often be used to determine the mechanism and rate of transitions. An important challenge is to reduce the computational effort in such calculations, especially when ab initio or electron density functional calculations are used to evaluate the energy since they can require large computational effort. Gaussian process regression is used here to reduce significantly the number of energy evaluations needed to find minimum energy paths of atomic rearrangements. By using results of previous calculations to construct an approximate energy surface and then converge to the minimum energy path on that surface in each Gaussian process iteration, the number of energy evaluations is reduced significantly as compared with regular nudged elastic band calculations. For a test problem involving rearrangements of a heptamer island on a crystal surface, the number of energy evaluations is reduced to less than a fifth. The scaling of the computational effort with the number of degrees of freedom as well as various possible further improvements to this approach are discussed.

Maxwell’s equations were considered for the electromagnetic field propagating in doped graphene taking spatial inhomogeneity in the threedimensional case. The electronic spectrum for the graphene subsystem was obtained from the model taking into account the Coulomb impurity. The effective equation for the vector potential of the electromagnetic field was solved numerically. A comparison of the forms of extremely short optical pulses is done for the case with recording inhomogeneities and one without.

The analysis of achievements, problems and prospects of high-temperature superconductivity (HTSC) in the macro- and nanostructured materials has been given. The main experimental results and theoretical models describing the physical mechanisms of the superconductivity appearance at phenomenological and microscopic levels, including change in the energy spectrum of atoms in these materials with the advent of the ‘superconducting’ gap at temperatures below the critical transition, as well as the above-critical temperature ‘pseudo-gap’ have been analyzed. Although the origin of the pseudo-gap is not completely understood, it can be considered as an independent phase transition in the substance prior to the transition to the zero resistance state and insusceptibility (or insensitivity) to external magnetic field in high-temperature superconductors. Features of multi-gap and gapless superconducting materials as well as their ability to further increase the temperature of supercritical transition are discussed. Large resources to create the necessary electron and phonon spectra in the process of high-temperature superconductivity formation are associated with the use of nanoscale structures and nanoparticles of conductors and dielectrics. Electrical conductive contacts between nanoparticles and tunnel chains of nanoclusters, where delocalized electron spectra form similar energy shells to the atomic or nuclear shells, play a significant part here. It is required to further investigate the occurrence of high-temperature superconductivity at the level of interphase layers (non-autonomous phases) in nanostructures containing a large fraction of the substance in this condition. It is essential to develop adequate methods for synthesis of nanoparticles of variable size, structure and morphology, as well as techniques for their consolidation that would ensure the preservation of superconductivity of individual nanoparticles, their chemical, thermal, magnetic and current stability in the dissipative processes with functional and fluctuation effects.

A new model of phonon transmission across interface between two crystals is proposed which takes into account the mismatch of crystal lattices. It has been found that the mismatch of lattices results in phonon scattering at the interface even in the absence of defects. As it has been shown, at the normal incidence, longitudinally polarized phonons have much larger transmission coefficient than that of transversely polarized phonons, excluding special resonance cases. Allowance for this factor results in a calculated Kapitza resistance value that is approximately three times greater. For the quasi one-dimensional case, an exact solution has been obtained.

The paper presents a comparative consideration of sp² nanocarbons and their silicon and higher tetrels analogues from the viewpoint of the spin molecular theory taking into account the electron correlation in open-shell molecules. High radicalization of silicene and quantum instability of flat honeycomb 2D structures of germanene and stanene make all the species phantom materials leaving graphene the only one-atom thick 2D solid free of the crucial restrictions.

A number of simple model systems are used to examine the applicability of the “tangent technique”, employed in the small-angle X-ray scattering for estimating the particle size distribution function, as well as to ascertain the relative contributions of the scattering intensity by differently sized particles to the total scattering intensity. The undertaken analysis has shown that, even in the most favorable case-an ensemble of two groups of different-size particles-the “tangent technique” cannot be used either to find the particle size proper, or to ascertain the relative contributions of individual groups to the total scattering intensity.

The key problem of the orbital-free approach is calculation of kinetic energy, especially for hetero-atomic systems. In this work, we used the mono-atomic functionals of kinetic energy to construct the kinetic functionals of complicated systems. We constructed some atomic weights associated with densities of single atoms and then calculated kinetic functions for some atomic complexes. For the examples of SiC, SiAl, AlC, SiO and CO dimers we have demonstrated possibility of our approach to find equilibrium interatomic distances and dissociation energies for hetero-atomic systems.

The dependencies of critical energy density and corresponding hot-spot temperature were calculated in terms of thermal model of energetic materials laser initiation for 12 metal nanoparticles in pentaerythritol tetranitrate (PETN) at pulse duration 12 ns. We showed that the critical hot-spot temperature depends mostly on the nanoparticle’s radius while its dependence on the specific heat of the metal is much weaker. The equations for the critical parameters of initiation on radius and specific heat of the nanoparticles were derived. The results are essential for the explosive compounds for optical detonator cup optimization.

Wet chemical techniques have been used to synthesize undoped and Mn-doped nanoparticles at room temperature. Highly stable pure and 5.0 weight% Mn-doped ZnO nanoparticles have been prepared. The morphologies, structures and optical properties of the as-prepared samples were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and UV-Vis spectra. The results clearly reveled that both the pure and doped samples had a wurtzite hexagonal phase. The SEM studies illustrated that grain size decreases with Mn doping, with average diameter ∼30 nm, which is in good agreement with the average crystalline size calculated by Scherrer’s formula. The strong absorption band in the UV region for the prepared samples can be attributed to the band edge absorption of the wurtzite hexagonal ZnO.

Results thermodynamic analysis of processes in the TiO₂ – H₂O system in a wide range of variation of parameters determine the regions of sustainable existence of titanium dioxide in the form of rutile and anatase modification. The results of thermodynamic prediction on the possibility and conditions of sustainable existence of TiO₂ with the rutile structure have been confirmed in experiments.

The Fe₃O₄@HxMoO₄·nH₂O nanolayers were synthesized on the solid surface for the first time by Successive Ionic Layer Deposition (SILD) method with using an aqueous Fe₃O₄ suspensions and (NH₄)₂MoO₄ solutions. The obtained nanolayers were investigated by XRD, SEM, EDX, FTIR spectroscopy and magnetization measurement techniques. SEM images showed that the nanolayers formed by nanoparticles of size approximately 15–20 nm. The synthesized nanolayers exhibited superparamagnetic properties with the saturation magnetization value of 55 emu/g.

Polystyrene films prepared by radical polymerization can conduct electric current in metal-polymer-metal structures with film thicknesses of up to 20 nanometers. Films of polystyrene and graphene oxide composite with thickness up to 3 micrometers, synthesized in similar conditions have the same electric properties. This effect is explained by presence of highly conductive graphene oxide inclusions in the dielectric polystyrene matrix.