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The properties of a Compton neutron detector with the emitter of metallic Hf were studying in this work. Using the previously calculated the emitter material nuclide composition during reactor irradiation, the dependence of the emitter signal value on the irradiation time was obtained with a step of 1 year for 5 years. It is shown that the composition modification due to nuclear transmutations changes the rate of an electric charge generation in the emitter.

Based on the data of ab initio calculation of the structure of (RSO3)2Mg (H2O)18 and (RSO3Rb)2(H2O)16 clusters, which simulate the structure of swollen sulfostyrene ion exchangers in the corresponding ionic forms and a water cluster of comparable size, the numbers of water molecules directly bound to cations and their coordination numbers, including the oxygen atoms of the sulfonic groups linked to the cation, were calculated. It is shown that the first molecular layer around the magnesium ion is formed from water molecules with the highest binding energy with the cluster, and around the rubidium ion – from the molecules of the nearest environment with the lowest binding energies. This is explained by the fact that the transfer of water molecules from its volume to magnesium hydrate is energetically favorable, but not to rubidium hydrate. Therefore, the magnesium ion builds its hydrate mainly from water molecules with the highest binding energy in order to obtain the greatest energy gain, and the rubidium ion – from molecules with the lowest energy, which provides the smallest energy loss.

Curves of potentiometric titration of fully protonized fibrous ion exchangers with potassium hydroxide against the background of 1 M KCl in the presence of chlorides of Ni2+, Со2+, Сu2+ and Ca2+ were obtained. The ion exchangers were synthesized by modifying of industrial polyacrylonitrile fiber with diethylenetriamine and triethylenetetraamine and predominantly contained functional groups R-CO-NH- (CH2CH2NH)nH (n = 2 or 3) and a small amount of carboxyl groups. The sorption of Ni2+, Со2+, Сu2+ и Ca2+by ion exchangers was calculated from the data obtained depending on the pH of the medium. It was found that the investigated ion exchangers with high selectivity sorb heavy metal ions in a wide range of acidity of solutions (pH 2–9) due to the formation of metal-polymer complexes with polyamine functional groups. The maximum sorption capacity is 1.5–2.7 and 4–5 meq/g for ion exchangers with n = 2 and 3, respectively.

Titration curves of H-forms of the fibrous chelating sorbent with iminodiacetic groups based on industrial polyacrylonitrile fiber Nitron with potassium hydroxide in 1M KCl solution in the presence of Ni2+, Co2+, Cu2+ and Ca2+ chlorides were obtained. The method used made it possible to simultaneously measure the pH of the solution and the concentration of the divalent cation at each point of the titration curve. From these data, the dependences of their sorption values on the pH of the equilibrium solution were calculated. The curves of direct and back titration practically coincided in all cases. As the pH changed during titration, precipitation was observed at pH values of precipitation of the corresponding hydroxides. In this case, the increase in pH was suspended or greatly slowed down by adding alkali to the titration cell. The formation of a precipitate occurred mainly in a solution for Co2+ and Ni2+ (pH 8), when the ion exchanger was saturated with a metal ion. In the case of Cu2+ (precipitate formation pH 4), Cu2+ sorption occurs at both lower and higher pH due to ionization of carboxyl groups and partial dissolution of the precipitate. In all cases, the maximum sorption of Ni2+, Co2+, Cu2+, Ca2+ corresponded to the formation of sorption complexes of the R–N(CH2COO-)2Me2+ type.

By the method of potentiometric titration of a fibrous aminocarboxylic polyampholyte with a predominant content of carboxyl groups, the equilibrium of the cation exchange of calcium, magnesium, and potassium ions for a hydrogen ion was studied. Due to the low solubility of calcium and magnesium hydroxides in these cases, titration was carried out by Ca(OH)2 and Mg(OH)2, which are formed in solution upon contact with the H-form of the ion exchanger оf increasing portions of solid CaO and MgO. This made it possible to obtain titration curves in a wide range of pH and calcium and magnesium chlorides concentration (0–0.1 eq./L). The dependences of the swelling of ion exchangers on the neutralization degree with the bases of the studied cations are obtained. The coefficients of ion-exchange equilibria are calculated. It was found that the swelling of the ion exchanger is relatively little dependent on its ionic form. The ion exchanger has a higher affinity for calcium than magnesium ion.

The effectiveness of using «Asepta plus remineralization» special toothpaste, combination of the same toothpaste and «Asepta parodontal fresh» rinse or «Asepta remineralizing gel» (Vertex CJSC, St. Petersburg, Russia) using analysis technique of the structure and severity of the interior disease sight based on psychosensorial-anatomy-functional desadaptation syndrome. It was established that patients who used «Asepta plus remineralization» toothpaste and «Asepta remineralizing gel» on day 3 showed adaptation to the conditions of their existence. Among the patients using «Asepta plus remineralization» toothpaste and «Asepta parodontal fresh» rinse, despite the positive clinical effect of their use on day 3, there was a violation of adaptability to living conditions. In case of the isolated using of «Asepta plus remineralization» toothpaste for oral hygiene, adaptation to their conditions of existence occurred by 7 days of patient observation. The obtained information is important for planning secondary prevention events for dental hyperesthesia, which allows recommending oral care products to patients taking into account the peculiarities of the clinical course of this pathology.

The article analyzes a set of medicinal-plant species in arid and semiarid biomes of Russia. The species diversity of medicinal plants in general, as well as those used to treat diseases of various classes, is determined. A statistical analysis of the relationships between the number of species of medicinal plants in regional biomes and climatic indices is carried out; the corresponding thematic schematic maps are constructed and analyzed. It is shown that the number of medicinal-plant species is related to the total biome species number. This, in turn, is determined by the geographic location, which determines the average annual temperature and precipitation in the regions. The closest established relationship was between the number of medicinal-plant species and the average annual air temperatures. A relatively high relationship was found between the species number and the average annual precipitation. In the analysis of the relationship between the number of medicinal-plant species used to treat certain classes of diseases and the climatic factors, the picture turned out to be similar.

Structural and electronic characteristics of molecular models of swollen polyacrylic and sulfostyrene-type cation exchangers in sodium and potassium ionic forms are calculated within the non-empirical HF/basis set method using the MINI Huzinaga basis set and the Firefly program. The obtained data are compared with those for water clusters of a comparable size. The molecular models include four and two monomeric units of corresponding polymers with ten water molecules per functional group; the water clusters contain 20 and 40 water molecules. The following characteristics of the model structure are obtained: the number and the types of the nearest neighbors of cations and water molecules; the distances between the interacting ions and the atoms; the orders of interionic and ion-molecular bonds; binding energy distribution of water molecules in the systems; number and length distributions of hydrogen bonds; the number and character of $$\text{RCO}_{2}^{-}\cdots {{\text{I}}^{+}},\ \text{RSO}_{3}^{-}\cdots {{\text{I}}^{+}}\ \text{and}\ {{\text{H}}_{\text{2}}}\text{O}\cdots {{\text{I}}^{+}}$$ bonds. The lengths of hydrogen bonds and the total number of intermolecular and ion-molecular bonds per water molecule in water clusters are established to be similar to those in Na+ and K+ molecular models of ion exchangers. The first coordination layer around both ions is filled with oxygen atoms of water molecules and fixed anions. The coordination numbers of Na+ and K+ are almost equal to those in aqueous solutions. The calculations indicate that direct interaction of Na+ and K+ with the anionic groups is responsible for the difference between their ion exchange selectivities on carboxylic and sulfostyrene ion exchangers. The Na+ ion forms direct largely covalent chemical bonds with the fixed carboxylate anion. The K+ ion forms long electrostatic bonds with the carboxylate group. This accounts for a higher selectivity of Na+ on carboxylic ion exchangers than that of K+. The K+ ion forms long direct electrostatic bonds with the fixed sulfonate anion. The Na+ ion does not form direct bonds with the sulfonate due to strong hydration of the former. This accounts for a higher selectivity of K+ on sulfonic acid resins that that of Na+.

This article is devoted to the phytochemical study of fresh and dried samples of buckwheat grass, the preparation of which was carried out from plants cultivated in pot culture using pharmacopoeial qualitative reactions. The presence of tannins and flavonoids was identified, and using the method of thin-layer chromatography, using GSO Rutin, rutin was identified, which allows us to consider potted buckwheat culture as a promising source of rutin production.

A mathematical model for description of the sorption capacity of ion exchangers on alkaline compounds protonizable in aqueous solutions (exemplified by ammonia, mono-, diand triethylamine) was proposed. The Henry’s constants for these substances were experimentally determined. The model accounts for the concentration and acid-base properties of the sorbate, relative air humidity, acid-base properties and exchange capacity of the ion exchanger, as well as spatial availability of functional groups for interaction under conditions of limited permeability of polymeric ion exchanger. The applicability of the model is illustrated by processing the experimental results on the sorption of ammonia and ethylamines by fibrous carboxylic and sulfonic cation exchangers. Good agreement between the calculated and experimental data is observed.

The transport characteristics of single-atom transistors with charge centers based on Sc, Cr, Ru, Rh, and Pt atoms are studied. Single-particle electron spectra of molecules of the coordination compound of these atoms with an aurophilic terpyridine derivative in different charge states are calculated and their features are analyzed. The effect the length of linkers have on the properties of effective tunnel barriers and transport characteristics of a single-atom transistor is studied.

New information on the state of water molecules and ions in the alkali ion forms of sulfostyrene resins have been obtained by joint application of thermodynamic and quantum chemistry methods to treatment of experimental water sorption isotherms taken from the literature. The theoretical water sorption isotherms have been computed from suggested earlier model of Predominant Hydrates. The model parameters were obtained with the help of quantum chemical calculations of structures of the swollen ion exchangers. Ab initio non-empirical SCF MO LCAO method has been used. The molecular models included fragments of the polystyrene chain with two sulfonic groups and the number of water molecules identical to that in the resins with 10% divinylbenzene. The theoretical water sorption isotherms for all alkali metal forms accurately describe the experimental data in the assumption of presence in the resin three (Li+ and Na+) or two (K+, Rb+ and Cs+) predominant hydrates. The calculations allowed obtaining the following characteristics of the molecular models: binding energy of the water molecules to the swollen ion exchanger, Gibbs' energy of the hydrates formation, distances between the water molecules and ions, lengths of the hydrogen bonds and some other parameters. These data allowed explaining physical reasons for the difference in properties of the alkali ions related to the water “structure forming” and “structure breaking” subgroups. The results of the quantum chemistry calculations clearly indicate separation of water molecules in the resin into several groups differing in the binding energy and the distances to the cations. The number of hydrogen bonds per water molecule in the ion exchanger is about 25% less than in the bulk water, but the total number of intermolecular bonds (hydrogen and ion-molecular) is approximately the same as in the bulk water. Intermolecular bonds in the ion exchanger form an integrated net in which the mobile and the fixed ions function as the knots.

The perspectives of using ion-exchange soils for growing plants in zero-gravity field are described. Standard methods for obtaining ion-exchange soils are not suitable for weakly dissociating ion-exchangers. Methods for obtaining ion-exchange soil based on weakly dissociating fibrous ion exchangers are proposed. The method using concentrated solutions made it possible to obtain ion-exchange soils with a larger content of deficient ions (K+ , NO3 – ). The suitability of the obtained ion-exchange soils was confirmed by a biological experiment.

The method of parameterization of the electron energy spectrum of molecules is used to theoretically study the specific features of the energy spectrum of a family of molecules of the monometallic coordination compound of terpyridine with Rh, Ru, and Pt atoms and the electron transport properties of molecular single-atom transistors based on this family of molecules. The coefficients for the parametric shell model of the energy spectrum are obtained for the studied molecules. It is demonstrated that the electron-transport characteristics of molecular single-atom transistors with atoms of transition metals with similar numbers of d electrons have similar shapes and features.

A novel technique for the production of metal electrodes of a nanotransistor with a nanogap less than 4 nm between them is developed on the basis of controlling the electromigration of previously suspended nanowires of the system. A method that allows the embedding of a molecule of Rh(III) terpyridine with aurophilic ligands between electrodes is elaborated, as well. The characteristics of electron transport through a system that consists of the specified molecule with a single-atom charge center indicate the correlated (single-electron) tunneling of electrons.

The paper describes the methodology for the calculation of neutron fluence and energy release in WWER-1000 reactor cavity and baffle using the Monte Carlo MCNPX code. It formulates an approach to the simulation of a 3-D neutron source and conditions for the transport of neutrons and photons in the core. The research presents preliminary results of neutron fluence and energy release calculation in WWER-1000 reactor cavity and baffle.

An ecological and geographical analysis of the distribution of poisonous plants in the regional biomes of Russia and the effect of arid conditions on it are presented. On the territory of Russia, 82 of the most toxic species of vascular plants (belonging to 34 families) were identified; of them, 55 were poisonous species of the genus Aconitum. Cartographic analysis demonstrated that the smallest number of poisonous plant species (excluding species of the genus Aconitum) is confined to the plain biomes of the forest-tundra and tundra, and the largest number of such species grows in lowland steppe biomes. In the lowland desert biome and in some mountain biomes, the number of poisonous plant species is also significant but is slightly lower than in the steppe biomes. The maximal number of species of the genus Aconitum was detected in the mountainous Far Eastern biomes. Correlation analysis of the relationship between the number of plant species and climatic factors revealed the maximal correlation between the total number of poisonous plant species (excluding species of the genus Aconitum) with the average annual air temperature.

We report on a fabrication method of extremely small metallic nanostructures which uses commercially available polystyrene with low molecular weight as a negative resist for electron-beam lithography. The samples were covered with polystyrene by physical vapor deposition. The method allows to form structures with a high (5–10 nm) spatial resolution and a high yield on non-uniform arbitrary shaped surfaces. The technological processes for forming line or dot arrays, electrodes with nanogaps, and radially located electrodes were developed. The process parameters are presented in this work. The possibility of fabrication of nanostructures on a cantilever tip apex of the scanning probe microscope was also demonstrated.

Colloidal membranous vesicles based on the functionalized liposomes are promising for development of novel efficient systems of controlled and stimuli-triggered drug delivery. In particular, the specific metabolism of cancer cells results in significant acidification in tumors, and thus the corresponding pH value changes can be used as a stimulus for drug release specifically in the tumor areas. pH-sensitive liposomes can be formed via incorporation of special pH-sensitive amphiphilic compounds into the liposomal membrane. Molecules of such compounds undergo a conformational transition caused by certain changes in the pH value of aqueous environment and resulting in corresponding membrane perturbations with rapid leakage of drug content from those liposomes into the areas with corresponding acidity. In the present work the pH-induced changes of Langmuir monolayer compression isotherm and of the structure of corresponding Langmuir-Blodgett films of pH-sensitive synthetic lipid trans-4,5,didodecyloxycarbonyl-trans-2-morpholinocyclohexanol have been observed and studied. The substantial expansion of Langmuir monolayer of that lipid caused by change of the aqueous subphase pH value from 7 to 5 was observed. Corresponding monolayer Langmuir-Blodgett films were deposited on mica substrate surface and studied using AFM technique. The substantial differences in the structure of Langmuir-Blodgett films deposited at pH values 7 and 5 were found. The observed effects directly demonstrate the pH-induced structural transformations in organized condensed planar molecular systems formed by pH-sensitive lipid molecules which underlie the pH-sensitivity of corresponding liposomal bilayer membranes containing such lipids.

Development and study of novel biomimetic and biocompatible functional nanofilm structures, surfaces and colloid membranous vesicles are currently important from fundamental and applied viewpoints. They can serve as model systems for insight into the basic structural-functional interconnections and physicochemical mechanisms at the nano-scale in biomembranous systems, and are useful for development of engineering solutions efficient for bio-medical applications including controlled drug delivery. We present here the results of a study of novel nanofilm composite structures (Langmuir monolayers, Langmuir-Blodgett films and liposomes) based on the interfacial complexes formed by biogenic lipid phosphatidylcholine, synthetic amphiphilic water-insoluble polyamine stearoylspermine (a derivative of biogenic polyamine spermine and stearic acid), colloid cationic ligand-free magnetite nanoparticles and polyanions (DNA, Poly(styrenesulfonate)). It was found that stearoylspermine molecules formed stable Langmuir monolayer on an aqueous subphase surface and that monolayer compression isotherm changed as a result of interactions of the stearoylspermine monolayer with aqueous subphase components (colloid cationic magnetite nanoparticles and polyanions). Monolayer Langmuir-Blodgett films of interfacial polycomplexes formed by stearoylspermine and magnetite nanoparticles or DNA molecules were deposited onto the mica substrate surface and the structure of polycomplex films was investigated using AFM. The data obtained using Langmuir monolayer technique were further used in formation of new composite nanofilm magnetic colloidal membranous vesicles based on the interfacial polycomplexes of phosphatidylcholine, stearoylspermine, magnetite nanoparticles and polyanions. The nanocomposite membranous vesicles were prepared successfully by sequential adsorption of colloid cationic ligand-free magnetite nanoparticles and polyanions onto the cationic surface of mixed phosphatidylcholine/stearoylspermine liposomes preliminarily formed using conventional ultrasound method. The formed vesicles were characterized by transmission electron microscopy, AFM, electron magnetic resonance technique, laser light scattering and electrophoresis techniques. The synthesized stable biocompatible nanocomposite magnetic liposomal vesicles can be useful in development of novel efficient systems for capsulation, targeted transport, controlled spatial localization and physical stimuli-addressed drug and DNA delivery.

We present the results of an experimental study of electron transport through individual phosphorus dopants implanted into a silicon crystal. We developed an original technique for single-electron transistor fabrication from silicon-on-insulator material with an island formed by single phosphorus atoms. The proposed method is based on well-known CMOS compatible technological processes that are standard in semiconductor electronics and may be used in most research groups. The large Coulomb blockade energy value of the investigated single-electron transistor (∼20 meV) allows one to observe single-electron effects in a wide temperature range up to 77 K. We measured and analyzed stability diagrams of fabricated experimental structures. We demonstrated a single-electron transistor with controllable electron transport through two to three phosphorus dopants only.

BACKDROUND This study presents the evaluation of two ion exchangers (granular and fibrous) impregnated with nanoparticles of hydrated ferric oxide (HFO) as selective sorbents for phosphate recovery from aqueous solutions. The hybrid impregnated anion exchangers combine the durability and mechanical strength of a polymeric weak base anion exchange resin with the high sorption affinity of HFO towards phosphate species. Dynamic experiments were carried out and data obtained were fitted to a well-known fixed-bed sorption model. RESULTS The theoretical sorption capacities reported by the Thomas model were in good agreement to the breakthrough experimental capacities determined from the sorption data. The sorption capacity decreased when using wastewater treatment plant secondary effluents in comparison with synthetic water mainly due to the presence of organic matter and suspended solids. The phosphate sorbed on the impregnated ion exchangers were efficiently desorbed by using a 0.5 mol/L sodium hydroxide solution, reporting up to 90% of recovery. CONCLUSION The reusability of sorbents was evaluated through five sorption–desorption working cycles. Fiban-As was able to operate up to three consecutive cycles with good sorption performance whilst a significant decrease of sorption capacity after the first cycle was observed for FO36 resin.

The single-particle electron energy spectrum and total electron energy spectra of a hydrogenically passivated central fragment of a coordination compound of rhodium with an aurophile terpyridine derivative (CCRATD) in different charge states ranging from–3e to +3e are obtained. The electron transport characteristics for a single-electron molecular transistor based on a CCRATD molecule are calculated and analyzed.

A combined procedural and hardware complex of electrophysical methods for management of submicrometric CMOS integrated circuit technology is developed and implemented. Programmable switching of the elements of the complex that makes it possible to utilize a mutually complementary measurement technique to obtain information needed to correct the production process is created. The complex includes programs to control the measurement and calculation of required characteristics.

Information on the state of proton and water molecules in sulfostyrene ion exchangers was obtained by joint application of thermodynamic and quantum chemistry methods to experimental water sorption isotherms from paper B.R. Sundheim , M.H. Waxman , H.P. Gregor , J. Phys. Chem. , 57 : 9 ( 1953 ) 974–978 . The model of Predominant Hydrates in combination with non-empirical quantum chemical calculation was used for calculation of theoretical water sorption isotherms. The experimental water sorption isotherms can be accurately described by the model accounting for the presence in the resins with different cross-linkages (0.4–23% DVB) of four hydrates (H 3 O + ; H 3 O + ·H 2 O; H 3 O + ·2H 2 O; H 3 O + ·6H 2 O) with practically the same Gibbs energy formation (stability constants). The IR and Raman spectra of dry and hydrated resins were interpreted by comparing theoretically calculated spectra of p-ethylbenzene sulfonic acid and experimental ones. Some corrections to their interpretation were suggested. The spectra show that complete dissociation of sulfonic groups occurs after sorption by the resin three water molecules per sulfonic group.

Valuable information on the state of water molecules in the ion exchanger can be obtained by joint application of thermodynamic and quantum chemistry methods to treatment of water sorption isotherms. An improved variant of the Predominant Hydrates model accounts for competitive process of formation in the resin of several hydrates forming an ideal mixture with the free water. The parameters of the model are number of hydrates, number of water molecules in each hydrate and Gibbs energies of the hydrates formation. The first two parameters can be obtained from quantum chemical calculation of structure of the molecular model of swollen ion exchanger and the energy state of the water molecules. The new approach was illustrated by its application to experimental data of Gregor H . P ., Sundheim B . R ., Held K . M ., Waxman M . H . Studies on ion-exchange resins . V . Water vapor sorption , J . of Coll . Sci ., 7 : 5 ( 1952 ) 511–534 on isopiestic data of water sorption by Li + and Na + forms of sulfostyrene resin with 10% DVB. The experimental water sorption isotherms can be accurately described by the model accounting for the presence in the resin of two hydrates with the same number of water molecules for Li + and Na + forms. The difference in the intensity of hydration reveals in the different Gibbs energy of the hydrates formation. The mole fraction of water in different hydrates and the free water was calculated. It appeared that more than a half of water molecules in both cases are free and enter the resin phase due to the entropy increase upon distribution of the free water between the solution and the resin.

The paper describes a generalized version of the voting protocol based on blockchain technology. The analysis of the proposed protocol is also carried out. The proposed protocol is based on such cryptographic primitives as digital signatures, asymmetric ciphers, and zero knowledge proof protocol. Safety analysis was carried out using the AVISPA software package. Anonymity was analyzed separately as part of this protocol by analyzing differential privacy.

This chapter provides a brief characterization of the groups of animal hosts and vectors that carry natural focal disease from the perspective of their roles in the formation and function of natural foci. The distribution of the most important epidemiologically significant mammals, birds and fish, as well as bloodsucking insects and ticks is examined and illustrated with a series of maps. The maps were compiled based on materials collected by the authors and are the result of long-term studies in various regions of Russia, as well as the analysis of a substantial amount of literary data and archival material. The animals’ ranges are given by individual taxonomic unite (class, order, etc.) and are represented in accordance with traditional methods of small-scale zoogeographical cartography. The textual commentary illuminated the role of each species in the formation and function of natural foci and their association with specific landscapes.

This study presents the evaluation of a fibrous ion exchanger impregnated with nanoparticles of hydrated ferric oxide (HFO) as a selective sorbent for phosphate. The hybrid impregnated anion exchanger (FIBAN-As) combines the durability and mechanical strength of a polymeric weak base anion exchange resin with the high sorption affinity of HFO towards phosphate species. The phosphate loading capacity at the common pH of waste waters treatment plant secondary effluents was 162 ± 12 mg PO43-/g sorbent. Dynamic experiments were carried out and data obtained was fitted to fixed-bed sorption models. The theoretical sorption capacities reported by the Thomas model were in good agreement to the breakthrough experimental capacities determined from the sorption data. The sorption capacity decreased in multicomponent system due to the faster ion exchange of competing anions compared to phosphate ions. The loaded FIBAN-As was efficiently regenerated by using a sodium hydroxide solution, reporting up to 90% of recovery. Finally, reuse of FIBAN-As was evaluated in three successively sorption–desorption cycles by using two regeneration solutions. A sorption capacity reduction of 23% and 30% was observed for acid and alkaline solutions, respectively after the third cycle

Here we present an original CMOS compatible fabrication method of a single-electron transistor structure with extremely small islands, formed by solitary phosphorus dopants in the silicon nanobridge. Its key feature is the controllable size reduction of the nanobridge in sequential cycles of low energy isotropic reactive ion etching that results in a decreased number of active charge centers (dopants) in the nanobridge from hundreds to a single one. Electron transport through the individual phosphorous dopants in the silicon lattice was studied. The final transistor structure demonstrates a Coulomb blockade voltage of ∼30 mV and nanobridge size estimated as [Formula: see text]. Analysis of current stability diagrams shows that electron transport in samples after the final etching stage had a single-electron nature and was carried through three phosphorus atoms. The fabrication method of the demonstrated structure allows it to be modified further by various impurities in additional etching and implantation cycles.

An electron transport through the extremely small gaps (1–5 nm wide) formed in narrow and thin gold nanowires by the electromigration method is studied in this work at various temperatures. A careful investigation of the final stage of a gap formation has shown a quantum character of a nanowire conductivity on this stage. Analysis of the electron transport characteristics through the resulting gaps was carried out. It shows that regimes of both a direct tunneling between electrodes and a “cold” emission into a barrier region were realized. Significant reduction of electron work function for gold electrodes of prepared gaps is revealed.

The effect of 2% (v/v) addition of ion exchange substrate to a sandy soil on the growth of Dactylis glomerata L., used as a test species, was studied. Four different exchange additives having pH values in the range 4.45–7.14 were evaluated in pot experiments. These additives were prepared as mixtures of monoionic forms of a strong acid cation exchanger and a weak base anion exchanger, loaded with nutrient ions. The additions of the ion exchange substrates to the sand affected plant growth advantageously, increasing the total dry biomass 3.8– 8.5 times. The most efficient additive appeared to be the substrate with the lowest pH because it contained the largest stock of nutrient elements. The excessive acidity of the additive was spontaneously neutralized in the mixtures with sand due to reaction of the acid excess with carbonates present in the natural sandy soil.

Актуальность темы определяется широким развитием и применением мобильных вычислительных средств, использующихся для хранения и обработки конфиденциальных информационных ресурсов. Данная работа посвящена вопросам защиты информационных ресурсов в бортовой системе транспортных средств от несанкционированного доступа. Выявлены недостатки существующих подходов защиты подобных систем вследствие широких возможностей злоумышленников вне контролируемых зон воздействия как на средства защиты, так и на пользователей системы. В связи с этим предложен подход защиты информационных ресурсов мобильных вычислительных средств, позволяющий получить доступ только в защищенных зонах. В статье разработана структурная модель многоуровневой системы защиты доступа к информационному ресурсу, включающая следующие уровни: физическую защиту, систему аутентификации, криптографическую и стеганографическую системы. Особенность данного метода заключается в том, что предлагается дополнить правила доступа к ресурсу данных подсистем контролем местоположения мобильного объекта информатизации. Это достигается за счет формирования ключей криптографической и стеганографической систем с учетом данных о географических координатах мобильного объекта. На основе данной модели разработано программное средство для защиты доступа к информационному ресурсу с учетом навигационного ключа, позволяющее повысить уровень защищенности мобильных объектов информатизации.

A planar topology for a nanoelectronic transducer based on glucose oxidase is designed for use in an enzymatic biosensor. Electromigration is used to create 5-nm gaps in Au nanowires. A method for the chemical modification of a silica surface with epoxysilane is developed and glucose oxidase is immobilized on the surface of a support by means of linking molecules. A technique for biochemical signal registration is developed. The eelectric response of the biosensor with glucose in a test solution and the dependence of this response on the glucose concentration are investigated.

The paper investigates the data on the fauna of the European Russia at the end of the XVIII century, contained in the materials of the General Land Survey, in comparison with contemporary data. The distribution ranges of the majority of large mammals observed in the study area two centuries ago, have not changed significantly, but the biological diversity has increased due to the emergence of new species.

Magnetic composite sorbents based on microporous and biporous hypercrosslinked polystyrenes (HCPs) with inclusions of iron oxide nanoparticles were studied by X-ray diffraction and differential thermal analysis. In microporous composites, the size of impregnated magnetite nanoparticles was less than ∼6 nm, the nanocomposites remaining optically transparent. Biporous HCPs (with micro- and macropores) had larger nanoparticles (∼16 nm). The sorption studies revealed that composite magnetic sorbents, as well as the starting hypercrosslinked polystyrenes, are effective adsorbents with high capacity for many compounds including toxic and physiologically active compounds.

Quantum-chemical calculations of vibrational spectra of the sulfonated ion-exchanger model p-ethylbenzenesulfonic acid hydrated by 1–10 water molecules and its dimer were calculated by the non-empirical SCF MO LCAO method with the 6-31G(d) basis set. The calculated results were compared with experimental IR and Raman spectra of sulfonated ion exchangers. The infl uence of hydration on the vibrational frequencies of functional groups in the ion exchangers was analyzed. It was shown that the sulfonic acid was completely dissociated if three and more water molecules per functional group were present. Bands near 1130 cm–1 were due to S–O–H bending vibrations in the absence of water molecules and C–S–O–H3O combination vibrations with 3–6 water molecules per sulfonic acid.

This paper discusses the relationships of zonal vegetation boundaries with some climatic indicators. Possible changes in subzonal vegetation boundaries in the territory of European Russia and Western Siberia are forecasted within the framework of one of the global warming scenarios. The revealed regularities make it possible to suggest a mathematical cartographic model of vegetation zonality for the 2046–2065 period.