Table of contents

The International Conference Functional Materials and Nanotechnologies (FM&NT-2011) was held in Riga, 5–8 April 2011 in the Institute of Solid State Physics, University of Latvia (ISSP LU).

The conference was organized in co-operation with projects ERANET 'MATERA' and National Research programme in Materials Science and Information Technologies. The purpose of the conference was to bring together scientists, engineers and students from universities, research institutes and related industrial companies active in the field of advanced material science and materials technologies trends and future activities.

Scientific themes covered in the conference are:

• theoretical research and modelling of processes and materials;

• materials for energetics, renewable energy technologies and phtovoltaics;

• multifunctional inorganic, organic and hybrid materials for photonic, micro and nanoelectronic applications and innovative methods for research of nanostructures;

• advanced technologies for synthesis and research of nanostructured materials, nanoparticles, thin films and coatings;

• application of innovative materials in science and economics.

The number of registered participants from 17 countries was nearly 300. During three days of the conference 22 invited, 69 oral reports and 163 posters were presented.

40 papers, based on these reports, are included in this volume of IOP Conference Series: Materials Science and Engineering.

Additional information about FM&NT-2011 is available in its homepage http://www.fmnt.lu.lv. The Organizing Committee would like to thank all speakers, contributors, session chairs, referees and meeting staff for their efforts in making the FM&NT-2011 successful. The Organizing Committee sincerely hopes that that the conference gave all participants new insights into the widespread development of functional materials and nanotechnologies and would enhance the circulation of information released at the meeting.

Andris Sternberg Inta Muzikante Janis Zicans

International Organizing Committee

• Andris Sternberg (chairperson), Institute of Solid State Physics, University of Latvia, Latvia, MATERA

• Juras Banys, Vilnius University, Lithuania

• Gunnar Borstel, University of Osnabrück, Germany

• Niels E Christensen, University of Aarhus, Denmark

• Robert A Evarestov, St. Petersburg State University, Russia

• Claes-Goran Granqvist, Uppsala University, Sweden

• Dag Høvik, The Research Council of Norway, Norway, MATERA

• Marco Kirm, Institute of Physics, University of Tartu, Estonia

• Vladislav Lemanov, Ioffe Physical Technical Institute, Russia

• Witold Lojkowski, Institute of High Pressure Physics, Poland

• Ergo Nommiste, University of Tartu, Estonia

• Helmut Schober, Institut Laue-Langevin, France

• Sisko Sipilä, Finnish Funding Agency for Technology and Innovation, Finland, MATERA

• Ingólfur Torbjörnsson, Icelandic Centre for Research, Iceland, MATERA

• Marcel H Van de Voorde, University of Technology Delft, The Netherlands

International Program Committee

• Inta Muzikante (chairperson), Institute of Solid State Physics, University of Latvia, Latvia, MATERA

• Liga Berzina-Cimdina, Institute of Biomaterials and Biomechanics, Riga Technical University, Latvia

• Janis Grabis, Institute of Inorganic Chemistry, Riga Technical University, Latvia

• Leonid V Maksimov, Vavilov State Optical Institute, Russia

• Linards Skuja, Institute of Solid State Physics, University of Latvia, Latvia

• Maris Springis, Institute of Solid State Physics, University of Latvia, Latvia

• Ilmars Zalite, Institute of Inorganic Chemistry, Riga Technical University, Latvia

• Janis Zicans, Institute of Polymers, Riga Technical University

Local Committee:

Liga Grinberga, Anatolijs Sarakovskis, Jurgis Grube, Raitis Siatkovskis, Maris Kundzins, Anna Muratova, Maris Springis, Aivars Vembris, Krisjanis Smits, Andris Fedotovs, Dmitrijs Bocarovs, Anastasija Jozepa, Andris Krumins.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

In the GaN-based ternary alloys, InGaN crystals have been recognized as key materials for e-h plasmas-exciton dynamics, because of large exciton binding energies (24.8 meV in GaN). We report investigations of creating and recombination dynamics of excitons in commercially important In_xGa_1-xN composition range from x = 0.1 to 0.18 in which nanoscale indium composition fluctuation occurs and formation of indium rich clusters acting as quantum dots (QD) can be expected. Three MOCVD grown samples having x = 0.1; 0.14 and 0.18 have been investigated using 3D picosecond transient PL spectroscopy. It has been found that the band to band photo excitation at 15 K in whole composition range results in creating of complex luminescence band represented by three close overlapping Gaussian shape single exciton bands. All three exciton bands show fast decay time constants in a picosecond range. For all the samples the PL intensity dependence on excitation pulse power for each exciton band is different. An increase of the excitation pulse power density results in the linear growth of the band at the higher photon energy side. The next energy bands with lower photon energy show correspondingly quadratic and cubic dependences on laser pulse energy and are caused by the formation of biexcitons and triexcitons. Fast decay kinetics and excitation of multi-excitonic complexes are evident for important role of quantum dots by quantum capture of excitons in the considered composition range.

The surface relief grating formation in amorphous As₂S₃ and azo-benzene polymer films strongly depends on the polarization state of recording beams. The surface relief grating formation efficiency of s-s and p-p recording beam combination can be essentially enhanced by additional illumination with orthogonal polarization. It is shown that the direction of mass transport on the film surface is determined by the direction of light electric vector.

In this work Er³⁺ doped NaLaF₄ material has been synthesized Along with the description of the synthesis route, luminescence spectra and decay kinetics of both traditional and up-conversion luminescence of Er³⁺ will be presented for different Er³⁺ doping levels. It will be shown that the main mechanisms involved in the creation of the up-conversion luminescence in NaLaF₄:Er³⁺ under excitation at about 975 nm are excited state absorption and energy transfer. Relative impact of either of the mechanisms in NaLaF₄:Er³⁺ depends on both the concentration of Er³⁺ and on the excitation wavelength: the increase of either the concentration or the excitation wavelength leads to the prevalence of energy transfer mechanism over excited state absorption mechanism.

In this work we tried to achieve multicolor up-conversion luminescence in low phonon energy material NaLaF₄ doped with different Er³⁺ Tm³⁺ and Yb³⁺ concentrations. Up-conversion luminescence was measured and main luminescence bands from Er³⁺ and Tm³⁺ in red, green and blue spectral regions were observed. The relative intensities of the luminescence bands could be changed by changing the doping levels of rare-earth ions. Changes in the up-conversion luminescence color could be achieved by applying different infrared pump power density. The color coordinates of the multicolor up-conversion luminescence depending on doping level as well as on the pump power density were presented in CIE (x, y) chromaticity diagram (1931).

Retro-reflective properties of six types and five different colors or retro-reflective materials were discussed in this paper. Reflectance optical indicatrix of samples was determined and compared to obtained psychophyisical data of perceived brightness of human observer. Microscopic structure of the retro-reflective active regions of RR's was studied. Statistically significant differences in reflectivity and brightness of various types and colors of RR's were found.

In this report holographic recording of polarisation and surface relief gratings in Disperse Red 1 (DR1) doped polyurethane polymer films was studied. In this material DR1 is chemically bounded to polyurethane polymer main chain. Polarization holographic recording was performed by two orthogonal circularly polarized 532 nm laser beams. Photoinduced birefringence is a precondition for polarization holograms recording, therefore a detailed study of a photoinduced birefringence and changes of optical properties was performed. The lasers with wavelengths of 375nm, 448nm, 532 nm and 632.8 nm were used as pumping beam for sample excitation. The photoinduced birefringence Δn was measured at 532 nm and 632.8 nm wavelengths. The photoinduced birefringence dependence on the pumping beam wavelength and intensity was investigated. Surface relief grating (SRG) formation was observed during polarization holographic recording process. A profile of SRG was studied by AFM. A relationship between SRG formation and photoinduced birefringence has been discussed.

This work is devoted to the topical issue – photo-induced formation of surface relief gratings (SRG) in thin layers of chalcogenide vitreous semiconductors (ChVS) without following complicated chemical processing. Holographic recording technique is one of the advanced methods for direct surface relief patterning in light sensitive materials. Because of the high light and electric field gradient it is possible to obtain surface structures directly in time with illumination. This incompletely explored process which is based on the photo-induced plasticity has been discussed in this paper from the side of a light intensity and its electric field on As₂S₃ and other ChVS.

According to the X-ray diffraction (XRD) studies, hydrocarbon films and flakes formed under deuterium plasma discharges in T-10 tokamak are amorphous with graphene-like sheets. They have atomic ratio (D + H)/C about 1 and higher. The XRD peak positions revealed the presence of structural defects with interplane distances of 0.12, 0.24 and 0.66 nm. The peak widths gave the in-plane sizes of the scattering structures equal to about 1 nm. The properties of such films were studied with application of small-angle and wide-angle X-ray scattering measurements, neutron diffraction and other techniques. These experiments have shown that the films contain about 63% of sp³ and ∼37% of sp² states. X-ray fluorescence spectroscopy employing synchrotron radiation revealed that the films contain at least 12 impurities of Fe, Mo, Cr, Ni, Nb and other transition metals. Difference between film properties on its opposite sides was revealed using Fourier-transform infrared spectroscopy and analysis of current-voltage characteristics (CVC). On the wall facing side of the film, graphite-like Csp² structures dominate. On the plasma facing side, diamond-like Csp³ structures prevail. Deuterium retention can be monitored by two groups of vibrational sp³ modes with different oscillator strengths, depending on the amount of deuterium in films.

Silica based composite material with palladium synthesized by extractive-pyrolytic method is used for hydrogen absorption-desorption experiments. The results obtained of the study on dynamic sorption experiments showed that Pyrex glass based composite sample reaches high hydrogen concentration in the material quite fast. Thought silica gel based composite material rapidly reaches ½ of hydrogen load but afterwards the amount of hydrogenation increases slowly. The overall amount of absorbed hydrogen for Pyrex glass based material exceeds the amount of absorbed hydrogen by silica gel based material approximately 5.6 times.

Titania with anatase structure is investigated due to its photo-active properties that can be used in the water photocatalysis applications and in the organic photovoltaic devices. In this work the anodization conditions are described to obtain stable thin film TiO₂ layers formed from vertically oriented nanotubes with approximate height 358 nm, inner tube diameter 48 nm and wall thickness 20 nm, but centre to centre distance 100 nm. Annealed at 500°C TiO₂ layer mostly consists from oxide with anatase structure, though XRD spectroscopy shows rutile impurities as well. Obtained nanotube layers are sensitive mostly to UV light.

When a conductive material is subjected to time-varying magnetic fluxes, eddy (Foucault) currents are generated in it and magnetic field of opposite polarity as the applied one arises. Due to the internal resistance of the conductive material, the eddy currents will be dissipated into heat (Joule heating). Conventional domestic water heaters utilize gas burners or electric resistance heating elements to heat the water in the tank and substantial part of the energy to use for it is wasted. In this paper the origin of electromagnetic induction heat generated by wind turbine in special heat exchange camera connected to water boiler is discussed and material evaluation performed using mathematical modelling (comparing the 2D finite element model with analytical and numerical calculation results).

The full study of perovskite type nanotubes with square morphology is given for the first time. The line symmetry group L = ZP (a product of one axial point group P and one infinite cyclic group Z of generalized translations) of single-walled (SW) and double-walled (DW) SrTiO₃ nanotubes (NT) is considered. The nanotube is defined by the square lattice translation vector L = l₁a + l₂b and chiral vector R = n₁a + n₂b, (l₁, l₂, n₁ and n₂ are integers). The nanotube of the chirality (n₁,n₂) is obtained by folding the (001) slabs of two- layers (with the layer group P4mm) and of three layers (with the layer group P4/mmm) in a way that the chiral vector R becomes circumference of the nanotube. Due to the orthogonality relation (RL) = 0, l₁/l₂ = −n₂/n₁ i.e. SW nanotubes with square morphology are commensurate for any rolling vector R(n₁,n₂). For SW (n,0) NTs the line symmetry groups belong to family 11 (T^D_nh) and are n/mmm or for even and odd n, respectively. For SW (n,n) NTs the line symmetry groups (2n)_n/mcm belong to family 13 (T_2n¹D_nh).

The line symmetry group of a double-wall nanotube is found as intersection L₂ = Z₂P₂ = (L ∩ L') of the symmetry groups L and L' of its single-wall constituents as earlier considered for DW CNTs. The symmetry group of DWNT (n,0)@M(n,0) belongs to the same family 11 (T^D_nh) as its SW constituents. The symmetry group of DWNT (n,n)@M(n,n) depends on the parity of M. For DW NTs with odd M, the line symmetry groups are the same as for their SW constituents and belong to family 13 (T_2n¹D_nh). For even M, the rotations about screw axis of order 2n are changed by rotations around pure rotation axis of order n so that DW NT line symmetry groups belong to family 11 (T^D_nh). Commensurate STO DWNTs (n₁,0)@(n₂,0) and (n₁, n₁)@(n₂, n₂) belong to family 11 (T^D_nh) with n equal to the greatest common divisor of n₁ and n₂.

The large-scale first-principles simulation of the structure and stability of SrTiO₃ nanotubes is performed for the first time using the periodic PBE0 LCAO method. The initial structures of the nanotubes have been obtained by the rolling up of the stoichiometric SrTiO₃ slabs consisting of two or four alternating (001) SrO and TiO₂ atomic planes. Nanotubes (NTs) with chiralities (n,0) and (n,n) have been studied. Two different NTs were constructed for each chirality: (I) with SrO outer shell, and (II) with TiO₂ outer shell. Positions of all atoms have been optimized to obtain the most stable NT structure . In the majority of considered cases the inner or outer TiO₂ shells of NT undergo a considerable reconstruction due to shrinkage or stretching of interatomic distances in the initial cubic perovskite structure. There were found two types of surface reconstruction: (1) breaking of Ti-O bonds with creating of Ti = O titanyl groups in outer surface; (2) inner surface folding due to Ti–O–Ti bending. Based on strain energy calculations the largest stability was found for (n,0) NTs with TiO₂ outer shell.

The two sets of commensurate double-walled boron nitride and titania hexagonally-structured nanotubes (DW BN and TiO₂ NTs) possessing either armchair- or zigzag-type chiralities have been considered, i.e., (n₁,n₁)@(n₂,n₂) or (n₁,0)@(n₂,0), respectively. For symmetry analysis of these nanotubes, the line symmetry groups for one-periodic (1D) nanostructures with rotohelical symmetry have been applied. To analyze the structural and electronic properties of hexagonal DW NTs, a series of large-scale ab initio DFT-LCAO calculations have been performed using the hybrid Hartree-Fock/Kohn-Sham exchange-correlation functional PBE0 (as implemented in CRYSTAL-09 code). To establish the optimal inter-shell distances within DW NTs corresponding to the minima of calculated total energy, the chiral indices n₁ and n₂ of the constituent single-walled (SW) nanotubes have been successively varied.

Comparative theoretical study of halogen atom (F, Cl, I) adsorption on the cation-rich ζ-GaAs(001)-(4×2) surface was performed using projector augmented-wave (PAW) method within the density-functional theory (DFT). For all considered halogens, the energetically preferable adsorption positions are found on top sites above dimerized Ga atoms. The interaction of halogen adatom with the dimerized atoms leads to the weakening of the interfacial chemical bonds at the initial stage of surface etching. The electronic properties of the clean semiconductor surfaces and their change upon halogen adsorption are discussed.

The properties of electron paramagnetic resonance (EPR) signal of oxygen dangling bonds in amorphous SiO₂ ("non-bridging oxygen hole centers", NBOHC) in excimer laser-irradiated amorphous SiO₂ were studied in the temperature range 20K to 295K. NBOHCs strongly affect optical and chemical properties of amorphous SiO₂ -based (nano) structures and their surfaces. The behaviour of their EPR signal is complicated due to a nearly degenerate electronic ground state. It was found that EPR signal has a non-Curie (∼1/T) T-dependence down to 40K, indicating that EPR-based concentration estimates routinely obtained at T = 77K underestimate the center concentrations at least by a factor of 1.7. The estimates of NBOHC concentration, based on EPR, are typically ∼10 times lower than those derived from optical spectroscopy, evidently due to incomplete accounting for temperature, microwave saturation and due to degenerate ground state coupled to disorder effects. The EPR signal of NBOHCs shows a strong microwave saturation at T<40K which allows for a high-sensitivity detection by 2nd-harmonic EPR registration techniques. Using it, the low intensity low-field wing of the EPR signal was shown to extend to g values as large as g = 2.4.

Composite membrane consisting from two different polymers – SPEKK and PVDF was used as two-phase sample for investigations with atomic force microscope (AMF). Three AFM modes were applied to analysis – surface relief, phase and surface potential scanning. Theoretical advantage of all three methods used for same sample is possibility to provide more detailed information on different phases in material. AFM results of surface investigation for pure SPEKK showed small fluctuation in height and phase (only difference in some nm and about 5°), what means that material is homogeneous. We found that for composite polymer membrane sample the changes in both modes are much more significant: for height it reaches 600 nm, but for phase – 20°. If surface potential of composite polymer sample clearly identifies some areas as SPEKK polymer, than in topography and phase images these places are identified as PVDF polymer only. This can be explained with the fact that polymers dissipate charge not only from surface but also little in depth. Even with such small potential contrast the surface potential mode of AFM can be used to detect distinct polymer structures not only on surface but also in a volume under the surface.

We investigated the EPR superhyperfine structure of the Mn²⁺ ion in the disordered BaF₂ crystalline media which tends to crystallize in the oxyfluoride glass-ceramics material. Obtained EPR spectra reveal explicit shf structure due to Mn²⁺ ion building into the BaF₂ lattice showing its usefulness as a probe in orientationally disordered and amorphous structures. Two types with explicit shf structure of Mn²⁺ ion characteristic EPR spectra were obtained in BaF₂ powder samples characteristic with broad (type 1) and narrow (type 2) hyperfine structure lines. Spectra of the ZnF₂-BaF₂ oxyfluoride glass-ceramics samples revealed explicit fine structure lines.

In this work we present a simply obtainable compound 2-(3-(4-(bis(2-(trityloxy)ethyl)amino)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile (IWK) capable of forming a thin solid amorphous film from volatile organic solvents (chloroform and dichloromethane). The synthesized glassy compound IWK absorption band is between 450 nm to 550 nm. It absorption maximums show small batochromic shift going from less polar to polar solvents. Compound IWK is also characterized with intensive photoluminescence, which maximum is dependant on solvent and is between 600 nm to 675 nm. The electron system of molecules were investigated with semi-empirical method ZINDO/S and show, that IWK type molecule chromophore fragment geometrical, electronic, and optical properties are not influenced by N-alkyl substituents.

Study of charge carrier transport in organic electroluminescent devices, organic photovoltaic devices, and organic field-effect transistors is one of the most important points. In order to realize comparable electron and hole transport in thin organic films with electrodes the energy structure of such devices are of great importance. In this work, we have studied electrical properties and energy structure of two carbazole derivatives. The threshold energy of photoconductivity quantum efficiency is 2.90 eV and optical energy gap is 3.3 eV in thin films is obtained. The values of work function of ITO, Au, Cu and Pd electrodes are energetically close to conductivity level of holes and holes injection dominates from electrodes. In these thin films local trapping states of holes are situated at holes conducting level. When electrode is Al layer the local shallow trapping states for electrons at E_t = 0.10 eV for compound 1 and at E_t = 0.18 eV for compound 2 are determined.

Organic thin films with semiconducting properties have been intensively studied in nowadays due to very promising applications in organic electronics, for example, organic photovoltaic. Among organic semiconductors, group of indandiones with their photoelectrical properties, thermal and chemical stability are good candidates for use in design of novel molecular electronic devices. We have investigated photoconductivity quantum efficiency and its spectral dependence of two dimetilaminobenzylidene-1,3-indandione derivatives. Values of the photoconductivity threshold energy and optical energy gap are obtained. These results are compared with calculated transfer energy gap estimated according to RHF ab initio calculations.

Proinflammatory cytokines mediate bone loss around the implants in patients with peri-implant disease. However, there is no complete data about the expression of cytokines into the bone around the implants. The aim of this work was to investigate the distribution and appearance of inflammatory cytokines and anti-inflammatory proteins in the bone of jaw of experimental rabbits in different time periods after HAp implantation. Material was obtained from 8 rabbits in lower jaw 6 and 8 months after HAp implants were placed. Tissues were processed for immunohistochemical detection of tumor necrosis factor alfa (TNFα), Interleukin 1, 6, 8, 10 (IL-1, IL-6, IL-8, IL-10) and defensin 2. Results demonstrated practically unchanged expression of IL-6 and IL-10 between both – experimental and control side 6 months after implantation, while IL-1 and IL-8 notably increased in control side. IL-1 and IL-10 expression did not change in either the experimental side nor the controle side after 8 months HAP implantation, but IL-6 and IL-8 demonstrated a decrease in the control sites. Only IL-8 was elevated with time in experimental sites, while IL-10 showed individual variations in 2 cases.

A novel approach to the design of planar gradient porous supports for the thin-film SOFCs and MIEC membranes is described. The support's thermal expansion is controlled by the creation of a two-component composite metal-ceramic foam structure. Thin MIEC membranes and SOFCs were prepared on the composite supports by the layerwise deposition of composite functional layers including complex fluorites and perovskites. Lab-scale studies demonstrated promising performance of both MIEC membrane and SOFC.

Thin layers of Ni-Fe alloys containing 76.0–85.0 wt.% Ni were electrodeposited from simple-salt and complex-salt electrolytes. The current density determined the Fe content of 24.0–15.0 wt.% in the layers. It was found that the electrodeposited thin Ni-Fe alloy layers approximately corresponded to FeNi₃ compound with the crystal size 10–15 nm, had a globular structure, which is characteristic of amorphous layers, and the coercitivity 51–55 Oe.

Formation of ultrathin anodised aluminium oxide (AAO) membranes with high aspect ratio by Al anodization in sulphuric and oxalic acids at low potentials was investigated. Low anodization potentials ensure slow electrochemical reaction speeds and formation of AAO membranes with pore diameter and thickness below 20 nm and 70 nm respectively. Minimum time necessary for formation of continuous AAO membranes was determined. AAO membrane pore surface was covered with polymer Paraloid B72^TM to transport it to the selected substrate. The fabricated ultra thin AAO membranes could be used to fabricate nanodot arrays on different surfaces.

GaN nanowires (NWs) were successfully grown by Vapor-Liquid-Solid (VLS) growth mechanism on GaN template using metal-organic vapor phase epitaxy (MOVPE) with diameters ranging from 20 to 200 nm and length up to few microns. The characterization by scanning electron microscopy (SEM) reveals an optimum growth temperature at 790°C and X-ray diffraction (XRD) investigations indicates oriented crystallinity of grown NWs.

Glassy metaphosphates of one, two, and three valence metals were studied by Rayleigh and Mandel'shtam-Brilllouin scattering (RMBS) spectroscopy and high temperature ultrasonic (HTUS) measurements in glass melts. Ratios of Rayleigh scattering intensities to the Mandel'shtam-Brilllouin scattering ones (Landau-Placzek ratios) were measured. Results are discussed in terms of density, concentration, and anisotropy fluctuations "freezing" when the melt is being cooled to solid glass state. Combined application of RMBS and HTUS made it possible to independently estimate the contributions of "frozen-in" density and concentration fluctuations into Rayleigh scattering. It was found that in most cases about half Rayleigh scattering intensity is caused by chemical nanoinhomogeneities of a glass, that is the "frozen-in" concentration fluctuations. Comparison of RMBS, HTUS and small angle X ray scattering (SAXS) data led to the conclusion that NaPO₃ and Ba(PO₃)₂ glasses were characterized by the highest chemical homogeneity on nanometer scale.

The plasma evaporation-sputtering method was used to manufacture composite materials of the Mg-Zr system. The ion-implanted deuterium desorption temperature variations depending on the component concentrations were studied. It has been established that the introduction of a Zr impurity to magnesium leads to the significant decrease of the deuterium desorption temperature (∼400K) as compared to the release from Mg samples. A step-like form of the curve of the deuterium desorption temperature testifies to presence of two various structural conditions at composite Mg-Zr depending on the relation of components. The hydrogen desorption data obtained using Mg-Zr composites can be used for the further invrstigations into the hydrogen storage materials containing chemical elements with a low solubility in the alloy components.

Particularly aerosol particles of fine dimensions are recognized to have a strong impact on the climate change, on the atmospheric energy budget, on the environment and on human health. In this study coarse aerosol particles with different black carbon mass concentrations were investigated by electrochemical impedance spectroscopy. Present work describes preparation of particulate matter samples for impedance measurements, the principles of the structure of electrochemical cell and the relationship between parameters obtained from impedance spectra and black carbon mass concentration. Using complex electrode it is possible to obtain qualitative impedance spectra of particulate matter which were sampled on glass fibre filters. The values of equivalent circuit's elements (R, Q and n) are depending on sampled mass of black carbon and mass of other carbonaceous components which are not black as well as they depend on filter pore packing with solid particles.

Transparent nanocomposite ZrO₂-SnO₂ thin films (0.1/0.9 (ZS19), 0.5/0.5 (ZS55) and 0.9/0.1 (ZS91) of ZrO₂/SnO₂ were prepared by sol-gel dip-coating technique. X-ray diffraction (XRD) pattern of ZS55 shows a mixture of three phases: tetragonal ZrO₂ and SnO₂ with the crystal sizes of 11 nm and 8 nm, respectively and orthorhombic ZrSnO4 with the crystal size of 14 nm. Scanning electron microscopy (SEM) observations show that microstructure of ZS55 consists of isolated SnO₂ particles dispersed in ZrO₂ matrix. An average transmittance greater than 85% (in UV–visible region) is observed in ZS55 thin film. The band gap of the nanocomposite thin film decreases from 5.33 to 4.24eV with increase in Sn concentration which can be directly employed in extending the range of tunability of the band gap. Photoluminescence (PL) spectra reveal an intense emission peak at 426nm in ZS55 sample which indicate the presence of oxygen vacancies in ZrSnO4.

Nanocrystalline BaMoO₄ was synthesized through auto-ignited combustion technique. The X-ray diffraction studies of BaMoO₄ nanoparticles reveals that the as-prepared powder is single phase, crystalline, and has tetragonal structure. The average particle size of the as-prepared powder from transmission electron microscopic is found to be 22nm. The thermal stability of the nano powder was examined using thermo gravimetric analysis and differential thermal analysis. The band gap determined from absorption spectra is 3.20eV.Photoluminescence spectra of the samples shows green emission peak. The dielectric constant and loss factor of the sample at 1 MHz is found to be 9.75 and 1.38×10⁻² at room temperature.

The influence of hydrogenation on the biocompatibility of different hydroxyapatite (HAP) materials was tested. Materials consisted of pure HAP, HAP substituted with manganese (Mn⁺²) and with magnesium (Mg⁺²) – all axially pressed and conventionally sintered for 2 h at 1200 °C; pure HAP isostatic pressed and sintered by a microwave technique for 15 min at temperature of 1200 °C. Biocompatibility was compared by enumeration of the number of osteoblast-like cells to the materials before and after hydrogenation. Obtained results show that the osteoblastic cells demonstrated a higher ability to attach to HAP if its surface was negatively charged. Hydrogenation altered the surface potential; HAP substituted with manganese – HAP(Mn) and with magnesium – HAP(Mg) demonstrated the highest ability to engineer the charge.

The method of determination of the flexural Young's modulus is based on a solution to the problem of compression of a thin-walled cylindrical specimen by two parallel planes (TWCS method). This method was employed to calculate the flexural modulus for PET polymer compositions. The flexural modules received by TWCS method were verified by comparing the experimentally measured eigenfrequencies by Polytec vibrometer with numerical results from ANSYS program.

Composite laminates are used extensively in the aerospace industry, especially for the fabrication of high-performance structures. The determination of stiffness parameters for complex materials, such as fibre-reinforced composites, is much more complicated than for isotropic materials. A conventional way is testing the coupon specimens, which are manufactured by technology similar to that used for the real, large structures. When such a method is used, the question arises of whether the material properties obtained from the coupon tests are the same as those in the large structure. Therefore, the determination of actual material properties for composite laminates using non-destructive evaluation techniques has been widely investigated. A number of various non-destructive evaluation techniques have been proposed for determining the material properties of composite laminates. In the present study, attention is focused on the identification of the elastic properties of laminated plate using vibration test data. The problem associated with vibration testing is converting the measured modal frequencies to elastic constants. A standard method for solving this problem is the use of a numerical-experimental model and optimization techniques. The identification functional represents the gap between the numerical model response and the experimental one. This gap should be minimized, taking into account the side constraints on the design variables (elastic constants). The minimization problem is solved by using non-linear mathematical programming techniques and sensitivity analysis. The results obtained were verified by comparing the experimentally measured eigenfrequencies with the numerical ones obtained by FEM at the point of optima

Amorphous Si thin films deposited on oxidized crystalline Si surface (111) were crystallized by thermal annealing and nanosecond green laser pulses. The Raman scattering spectra show that thermal annealing can provide nearly fully crystallized poly-Si film. Laser crystallization of amorphous Si is more flexible crystallization method, but it is more difficult to reach high levels of crystallinity. Depth studies of laser treated samples reveal a thin amorphous-like interlayer between substrate surface and crystallized Si film.

A new method of smectite clay enrichment has been developed. The method is based on dispersing clay in a phosphate solution and sequential coagulation. The product of enrichment is characterized with X-ray powder diffraction, wavelength dispersive X-ray fluorescence spectrometry, differential thermal analysis and thermogravimetry. Sorption of methylene blue and hexadecylpyridinium bromide on raw and purified clays was studied.

One of the main tasks of presented research are to impact the additional value on natural fabrics by adding them new properties with a metal nano-level coating, evaluate coating technologies. Having the ability to control the surface of a natural fiber offers great rewards that go far beyond pure economics as natural fibers are renewable and biodegradable. The paper describes the process of vacuum evaporation and magnetron sputtering of copper coatings on cotton textile materials, analysis of the metal coated textile surface by laser laboratory complex and SEM. The investigation results evince that laser laboratory complex measurements of reflected and through covered material transmitted light can be applied to trace the unevenness of deposited metal film on the covered fabric surface and its changes from exploitation impacts without samples destruction.

Vertically oriented nanowires (NWs) of single-crystalline wurtzite GaN have been fabricated on sapphire substrates, via metal organic chemical vapor deposition (MOCVD). We present ex situ investigations on orientation and structure of grown GaN nanowires on GaN(0001) surface using reflection high energy electron diffraction (RHEED). Both ordered and randomly oriented GaN crystalline structures have been detected.

The spark-plasma-sintering (SPS) method was used for sintering of different tungsten carbide (WC) and titanium carbonitride (TiCN) nanopowders obtained by the method of plasma synthesis. Dense, fine-grained monophase materials (WC and TiCN) were obtained at relatively low temperatures. Obtained results were compared with that for hot pressing (HP) method.

Electrochemical impedance spectroscopy (EIS) was used to investigate different Cu deposition regimes on Al surface obtained by internal electrolysis and to characterize properties of fabricated electrodes. EIS experimental data confirmed that Cu deposition by internal electrolysis is realized and the complex electrode system is obtained. The main difficulty in preparation of Al/Cu electrodes is to prevent aluminium oxidation before and during electrochemical deposition of Cu particles. In this work NaCl, CH₃COONa, K₂SO₄, mono- and diammonium citrate electrolytes were examined to determine their suitability for impedance measurements. Al/Cu-Al₂O₃ electrode composition was approved by equivalent circuit analysis, optical and scanning electron microscope methods. The most optimal Cu deposition mode using internal electrolysis was determined. The obtained results are promising for future electrochemical fabrication of nanostructures directly on Al surfaces by internal electrolysis.

Atomic and electronic structure of Me/α-Al₂O₃ interfaces (Me = Nb, Mo, Ta, W) is studied within the density functional theory. The interface structure as well as the work of separation of metal films from the oxide surfaces are calculated. Structural and electronic factors responsible for the strong adhesion of bcc metal films on the oxygen terminated aluminium oxide surface are analyzed. The chemical bonding mechanism at the differently-oriented interfaces is discussed. It is shown that the metal films adhesion strongly depends on the type of the oxide surface.