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Substrates based on the metal-polymer nanocomposites 2,3-dichloro-p-xylylene-silver (PCPX-Ag) that realize the effect of surface-enhanced Raman scattering (SERS) were developed. To obtain nanocomposites, the vapor-phase polymerization method was used (VDP), which makes it possible to control the nanocomposite microstructure. In the process of self-assembly during VDP, nanocomposite films with inclusions of silver particles were formed on the polycore substrates. Silver content varied from 2.5 to 16% vol. The possibility of using such substrates for the detection of low-molecular substances, for example 5,5′-dithiobis- (2-nitrobenzoic acid) (DTNB) analyte, by the SERS method with an enhancement factor of up to 104, was demonstrated. The dependence of the SERS spectra enhancement on the microstructure of the nanocomposite and the silver content was determined. The optical and morphological properties of nanocomposites were also investigated and their dependence on the silver content was shown. It has been demonstrated that the nanocomposite is SERS selective since when working with complex solutions in the presence of high molecular weight substances, signal enhancement was only observed for low molecular weight substances.

An anomalously high photosensitivity of $${\text{Cd}}{{{\text{S}}}_{{{\text{1--}}x}}}{\text{S}}{{{\text{e}}}_{x}}$$ granular films observed in the experiment is explained. It is assumed that the charge transfer mechanism based on surface states existing at the granule boundaries can be responsible for an anomalously high photocurrent-to-dark current ratio recently found in the study of the photoconductivity of $${\text{Cd}}{{{\text{S}}}_{{{\text{1--}}x}}}{\text{S}}{{{\text{e}}}_{x}}$$ granular films. It has been shown that the current of charge carriers in surface states flowing through the gaps between the granules at a certain film topology can exceed by many orders of magnitude the current associated with tunneling of charge carriers between the granules.

Direct metallation of 2-hydroxyphthalocyanine J-type slipped-cofacial dimeric ligand by Mg, Zn, Cu, Ni and Co salts has been carried out to obtain corresponding metal complexes selectively without any noticeable dissociation or polymerization of the starting ligand. Integrated analysis of aggregation properties in the synthesized series has been conducted with the involvement of AFM microscopy, UV/Vis spectroscopy and theoretical assessment. As a result, a nonlinear relationship between absorption and concentration was found, with aggregation beginning to appear at concentrations above 3.3 × 10−5 mol L−1 with predominant formation of trimers from the dimeric molecules in THF solutions.

Spectroscopy based on surface enhanced Raman scattering (SERS) is widely used as a method with extremely high sensitivity for molecular and chemical analysis. We have developed thin-film sandwich structures, in which, when used as sensitive elements for detecting organic compounds at low concentrations, high-amplitude spectra of surface enhanced Raman scattering are observed. Using gas-phase cryochemical synthesis and thermal sputtering in vacuum, SERS active sandwich structures Ag&ndash, poly(chloro-p-xylylene)&ndash, Ag (Ag&ndash, PCPX&ndash, Ag) were obtained. In the process of creating sandwich structures, the upper silver film takes the form of a complex island topology with submicron sizes. A series of samples were made with different thicknesses of the polymer and upper silver layers. SERS spectra of the analyte chemically adsorbed on the film surface were obtained, demonstrating a significant amplification (up to 104) compared with the control sample. The dependence of the gain on the silver concentration is characterized by a maximum polymer layer thickness of 600 nm and a 30 nm thick upper silver layer. A selective amplification of the low molecular weight compound spectra with respect to proteins was observed. A semi-empirical model is proposed that is in good agreement with the experimental results.

Novel 3-(ethylthio)phenyl-substituted phthalocyanine and naphthalocyanine zinc complexes were synthesised with high yields. The Suzuki cross-coupling reaction provides selective approaches to the initial mono- or di- 3-(ethylthio)phenyl-substituted phthalonitriles. The complexes obtained were characterised by 1H nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. Observation of the nuclear Overhauser effect was used for aromatic proton assignment. The correlation between the number of 3-(ethylthio)phenyl groups, the size of the π-system and the position of the Q-band was defined. Visualisation of the influence of increasing π-system size on aggregate size was provided by atomic force microscopy.

We perform a detailed investigation of coatings made of poly(p-xylylene) nanocomposites with embedded silver nanoparticles of sizes up to 12 nm and concentration up to 10.5 vol. %. We study their microstructure, mechanical, optical, and radiative characteristics. We reveal certain correlations between structural peculiarities and optical, as well as radiative properties. These correlations are due to fluctuations in distribution of nanoparticles in a polymer matrix and also due to the peculiarities of nanoparticles size distribution. We calculated optical dispersion coefficients for nanocomposites with different silver content. It was shown the refractive index ( n ) and extinction coefficient ( k ) is strongly dependent on the silver content and change within the 1.4–2.4 for n and 0–0.6 for the k . It is argued that poly(p-xylylene)silver nanocomposites can be used to construct multilayer coatings with required optical constant and conformal to any complex morphology.

Novel terbium(III), dysprosium(III), erbium(III) and lutetium (III) tetrapyrazinoporphyrazines with bulky 4-(tert-butyl)-phenyl groups, were obtained by metallation of porphyrazine ligand in high yields. The target complexes were identified by high-resolution matrix assisted laser desorption/ionization mass spectrometry, infrared and nuclear magnetic resonance spectroscopy. In nuclear magnetic resonance spectra, the proton signals demonstrate strong shifts for complexes with paramagnetic ions in comparison with lutetium one. The impact of peripheral (tert-butyl)phenyl groups and central ion nature on position of the main absorption bands in UV–Vis spectra was investigated. Two blends of gold nanoparticles (5 and 60 nm in diameters) and lutetium complex were prepared. The influence of the size of bare Au nanoparticles on core-shell structure of hybrid blends was investigated by transmission electron microscopy and atomic force microscopy. The nonlinear optical behavior of hybrid nanoparticles as well as initial lutetium (III) tetrapyrazinoporphyrazine was carried out using Z-scan measurements.

Selective synthetic approaches to novel single- and multiple-decker terbium(III) phthalocyaninates, bearing peripheral phenyl groups, were developed. The compounds were identified by nuclear magnetic resonance spectroscopy, high resolution mass spectrometry, Fourier-transform infrared and UV–Vis spectroscopy. From the X-ray data for initial 1,2-dicyano-4,5-diphenylbenzene it was shown that phenyl groups are not in the same plane, and dihedral angle between them equals 64°. Strong upfield shifts of the aromatic proton signals up to −131.62 ppm in the case of a triple-decker complex were found in the nuclear magnetic resonance spectra due to paramagnetic nature of terbium(III) ion. Stronger intramolecular interactions are observed for the sandwich-type phenyl-substituted terbium complexes comparing to tert -butyl-substituted analogs, earlier described in literature. In the case of the double-decker compound, this results in 142 nm hypsochromic shift of the intervalence absorption band. DC conductivity measurements were carried out for terbium bis phthalocyaninate. The formation of the ring-shaped self-assembled aggregates with a diameter of 400 nm was observed in thin solid films of the prepared terbium(III) compounds by atomic force microscopy.

Anomalous optical response for the metasurface fabricated from silicon resonators is investigated. Resonators have form of 3D micro cones – tips that are covered by semicontinuous silver film. Thus prepared metasurface exhibits anomalous optical response due to the excitation of metaldielectric resonances in visible and near IR spectral ranges. We investigate the effect of the “extraordinary” optical diffraction by tip-shaped metasurface. The multiple metal-dielectric resonances result in huge enhancement of the local electric field in-between metal particles placed on the surface of dielectric cones. SERS phenomenon is investigated by immobilization of DTNB (5,5’- dithio-bis-[2-nitrobenzoic acid]) molecules of on the metasurface.

Observation of the wanted Raman signal from SERS substrates is hampered by the background luminescence. We investigate the metasurface made of periodic silicon micro bars with thin silver layer on the top. The computer simulations as well as real experiment reveal the anomalous optical response of the metasurface is due to the excitation of the metal-dielectric surface resonances. We demonstrate the enhanced Raman signal from the organic molecules of 5,5-dithio-bis[2-nitrobenzoic] acid deposited on the microbar metasurface. The microbar metasurface exhibits large Raman/luminescence (signal/noise) ratio. As result it operates as an efficient SERS substrate.

Anomalous optical response for the metamaterial fabricated from silicon bar resonators is investigated. The resonators are manufactured in form of two-dimensional bars and covered by semicontinuous silver film. The calculations as well as real experiments demonstrate Wood anomalies in visible and near IR spectral ranges associated with excitation of the surface waves in metamaterial by means of diffraction of the incident light on the periodic bars. The multiple metal-dielectric resonances result in much enhanced local electromagnetic fields in-between metal particles placed on the surface of dielectric bars. The resonances can be tuned by varying angle of incidence, polarization, and geometry of the dielectric bars. It opens new venue in R&D SERS substrates including sensors detecting specific substances.

The first examples of planar binuclear porphyrazines sharing a common benzene or naphthalene ring based on a 3,4-thiophene moiety have been synthesized and characterized using nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, electronic absorption spectroscopy and magnetic circular dichroism. In order to enhance the interpretation of the electronic structures, quantum chemical studies were carried out. The formation of nanoaggregates in a solid film was shown using atomic force microscopy.

In this paper, we investigate the potential of facet structures of cerium dioxide for the purpose of increasing the intensity of the surface enhancement Raman scattering (SERS) signal. During the studies, a new metamaterial is developed. The metamaterial is based on facet cerium dioxide films and plasmonic nanoparticles that are immobilized on its surface. The new metamaterial provides an additional SERS signal amplification factor of more than 200. Thus developed material offers the prospect of increasing the sensitivity and selectivity of biochemical and immunological analysis.

A comprehensive study of the microstructure of poly(p-xylylene)-silver (PPX-Ag) nanocomposites is carried out using the method of light scattering indicatrix analysis. A stand for measurements of light scattering indicatrix and integral light scattering is created. Theoretical calculations of the PPX-Ag scattering indicatrices using Mie theory are performed taking into account the features of the microstructure of the nanocomposite. Good agreement of the experimental and theoretical studies of the PPX-Ag scattering indicatrices is obtained.

Optical properties of two-dimensional periodic systems of the dielectric micro bars and micro cones are investigated. Computer simulations as well as real experiment reveal anomalous optical response of the dielectric metasurface due to excitation of the dielectric and metal-dielectric resonances, which are excited in-between metal nanoparticles and dielectric cones and bars. In the metal-dielectric resonance local electric field can be orders on magnitude larger than the field in the plasmon resonance only. To investigate local electric field the signal molecules were deposited on the metal nanoparticles. We demonstrate the enhancement of the electro- magnetic field by detecting the Raman signal from the of organic acid molecules deposited on the investigated metasurface.

Optical properties of two dimensional periodic system of the silicon micro-cones are investigated. The metasurface, composed of the silicon tips, shows enhancement of the local optical field. Finite element computer simulations as well as real experiment reveal anomalous optical response of the dielectric metasurface due to excitation of the dielectric resonances. Various electromagnetic resonances are considered in the dielectric cone. The metal-dielectric resonances, which are excited between metal nanoparticles and dielectric cones, are also considered. The resonance local electric field can be much larger than the field in the usual surface plasmon resonances. To investigate local electric field the signal molecules are deposited on the metal nanoparticles. We demonstrate enhancement of the electromagnetic field and Raman signal from the complex of DTNB acid molecules and gold nanoparticles, which are distributed over the metasurface. The metasurfaces composed from the dielectric resonators can have quasi-continuous spectrum and serve as an efficient SERS substrates.

This article explores the theoretical foundations of public procurement system inRussia. The essence of the federal contract system is considered taking into account the historical aspect. It is proved that the contract system is the new fi nancial instrument used by the State in the area of procurement. Substantiated that public procurement can be defi ned as an important stage in the implementation of the state order, as a system of economic relations of economic agents regarding procurement, regulated by law and, in general, can be described as formed state contract system, which allows the most eff ective way to infl uence the procurement process and ensure the achievement of the highest socio-economic impact in this area.

An efficient synthetic approach to a novel substituted tetrathieno[2,3- b ]porphyrazine, its Mg, Zn, Lu complexes and a Lu triple-decker complex was developed. Spectral properties and aggregation phenomena of the target compounds were investigated by UV/Vis spectroscopy and atomic force microscopy (AFM). Electrochromic behaviour of the Zn complex was studied by electrochemistry and spectroelectrochemistry.

Iron film surfaces have been studied after their chemical treatment in a magnetic field. The chemical treatment of a metal leads to the appearance of a relief image that is interpreted as a “photograph” of magnetic scattering fields. The morphology of the relief image formed is shown to correlate with the domain structure of a magnetic film. The magnetochemical effect revealed allows the visualization of the dependence of the scattering field distribution at the sample surface on external magnetic field.

The processes of formation of metal-polymer poly-para-xylylene-Ag nanocomposites by solidphase cryochemical synthesis are studied. The temperature dependences of the electrical resistivity of the composites measured in the course of polymerization, which involves heating the cocondensate of p-xylylene monomer and metal particles, and on completion of the polymerization are presented. The findings are correlated to the results of the structural investigation of the obtained composite by the atomic-force microscopy, transmission electron microscopy, and x-ray diffraction. An empirical model of the process of nanocomposite formation is proposed. The mechanisms of electric conduction in nanocomposites are discussed.

Layered structures fabricated from thin ferromagnetic films (including structured ones) are proposed as bulk materials with high values of microwave permeability. Experimental data on microwave properties of such structures based on monolayer and multilayer nitrogen-doped iron films are presented. The influence of the skin effect, magnetostriction, and other physical phenomena on the microwave properties of such materials is discussed. The problem of the limiting values of permeability in the microwave band is considered in detail. Possible applications of such materials as radio-wave absorbing coatings and substrates for miniature stripline antennas are analyzed.

It is experimentally shown that the near- and mid-IR transmission coefficient of a 17-nm silver layer sputtered onto a Lavsan film with an irregular system of small holes is 2–6 times higher than the transmission coefficient of the same layer on a nonperforated continuous Lavsan film. This effect is wideband. It is observed at wavelengths of 1500–5000 nm. The physical-optics calculation of transmission of light through the holes in a silver film that are identical to the holes in the Lavsan film is unable to explain this effect since the hole diameter (200 nm) is too small. The system microstructure is studied with the atomic-force and electron microscopes. A possible mechanism of the effect of extraordinary transmission of radiation is discussed.

The study is conducted of thin Fe–N films produced by magnetron sputtering on mylar substrate. The correlations between morphology, structure, and magnetic static and dynamic properties of the films are found. The films under study have a columnar morphology. Both the average granule size and the length-to-width ratio of the granules increase with the film thickness that causes an increase of the effective anisotropy field. A small variation of nitrogen fraction in Ar+N 2 gas mixture in the sputtering chamber allows the location of magnetic loss peak to be controlled within the frequency range of 1–5 GHz. Therefore, the frequency dependence of permeability is determined not only by the crystalline structure and composition of the film but also by its morphology, thickness, and effective magnetic anisotropy. In particular, with the fixed concentration of nitrogen in the film, the frequency dependence of microwave permeability is determined greatly by the distribution of nitrogen atoms over different vacancies in the film structure.

Studies of the magnetoresistance of granular Fe/SiO2 films within the compositional range corresponding to insulators revealed a large positive magnetoresistance. The positive magnetoresistance reaches 10% in magnetic fields ∼100 Oe at room temperature and exhibits slow response times (∼2 min) to stepped magnetic-field variation. The nature of the effect is apparently associated with the influence of ferromagnetic cluster aggregates of iron nanoparticles on the magnetoresistance.

The results from magnetooptical studies of the influence of magnetochemical effects on the surface morphology and local magnetic properties of FeN alloy thin films and thin-film systems that consist of alternating silicon dioxide and FeN layers of submicron thickness, are shown. The dramatic influence of chemical etching on the surface morphology and magnetic characteristics of the investigated samples is revealed.

The effect of heating of substrates (75°C, 110°C, 145°C and 180°C), electrical bias (50, 75, 100, 125, 150, 200 and 250 V) on the substrate during preparation of amorphous films, and post-annealing on structure and properties of Finemet films were studied. Films were obtained by ion-beam sputtering a Fe 73.5 Si 16.5 B 6 Cu 1 Nb 3 alloy. The structural changes of films due to different annealing temperatures were studied by means of transmission electron microscopy (TEM; Philips CM 300) and X-ray diffraction analyzer (DRON-4). Magnetostatic properties measurements were made with the vibrating sample magnetometer (VSM). Annealing after sputtering decreases the coercive force but its magnitude depends on the preparation conditions. We found that film deposition onto heated substrates had a critical temperature between 110°C and 145°C, at which the film had coercivity H c >30 Oe . The samples deposited without the bias coercive force decreased after annealing. But the bias voltage during sample preparation reduced this effect of annealing.

The anomalous Hall effect is studied on Fex(SiO2)1−x nanocomposite films with x

An attempt to apply a SQUID microscope for visualization of magnetic structure in giant magnetic impedance (GMI) elements was undertaken. The measurements were carried out on the 1/spl times/10/sup -3/ mm thick permalloy strip with the in-plane sizes 6 mm/spl times/0.3 mm. The topography of the vertical component of magnetic field was imaged with a high spatial resolution close to 30/spl times/10/sup -3/ mm over the central part of a sample. The images taken in the applied magnetic field varied over the range /spl plusmn/4 kA/m reveal the domain structure with anisotropy perpendicular to longitudinal sample axis.

It has been experimentally shown that in near- and mid-IR-wave bands, the transmittance of 17 nm silver layer deposited onto a lavsan film with an irregular system of small holes is two to six times higher than that of the same layer deposited onto a uniform lavsan film. The effect is of a broadband type covering the wave range of 1500--5000 nm. The study of system's microstructure with the help of AFM and electronic microscope shows that the silver film is corrugated with the same system of holes as the lavsan substrate is. The evaluation made within the frames of physical optics approximation has shown that due to smallness of holes' diameter (200 nm), the additional transmittance through the holes is much less than the observed effect. A supposed mechanism of extraordinary light transmittance is discussed.

Thin ferromagnetic films are known to exhibit the highest possible microwave permeability of known magnetic materials. Magnetic materials with high microwave magnetic performance are useful for many technical applications. However, bulk rather than planar materials are frequently needed for the applications. Bulk materials with high microwave permeability may be produced as laminated structures of thin ferromagnetic films, possibly patterned. The paper presents experimental data on the microwave permeability of such laminated structures based on Fe films. Possible technical applications of the materials under study include thin wideband radar absorbers and miniaturized patch antennas.

Further enhance of the Raman scattering is the priority for the development of the modern molecular diagnostic methods. Expected increasing in detection sensitivity of the biological and chemical agents provides substantial progress in such areas as: proteomics (discovery of new disease markers), pharmacokinetics of drugs, analysis of toxins and infections agents, drug analysis, food safety, and environmental safety.In this paper we investigated the possibility of the facet structures, based on cerium dioxide to further enhance the SERS signal. During the studies a new metamaterial was developed. The metamaterial is based on the facet cerium dioxide films and plasmonic nanoparticles that are immobilized on its surface. The new metamaterial provides additional SERS signal amplification factor of 211. Thus developed material offers the prospect of increasing the sensitivity and selectivity of biochemical and immunological analysis.

The effect of intracellular application of isolated and purified forms of "core" oligoadenylates (2',5',ApApA, 2',5'ApApepoxyA and 3',5'ApApA) on the phosphorylation-dependent calcium channels in GH3 cells was investigated. The role of Mg2+ ions in realizing of the processes of enhancement of phosphorylation-dependent calcium currents and prolongation of their wash-out during whole-cell patch-clamp experiments was examined.

Using as an example SiO2/Cu/SiO2 and Al2O3/Cu/Al2O3 coatings in the wavelength range lambda=0.35-2.5 µm, the optical properties of the metal layers in three-layer insulator/metal/insulator systems have been studied. The indicated coatings are obtained by the method of layer-by-layer electron-beam sputtering on silicate glass. The dispersion dependences of the refractive index n and absorption index k of the intermediate copper layer in SiO2/Cu/SiO2 and Al2O3/Cu/Al2O3 coatings is determined for the first time, using a computational matrix method to calculate the optical constants (n and k) of the separate layers that make up the layered system. It is shown that the properties of the metal films in the coatings under consideration are mainly determined by microstructural effects.