Home – Home – Jornals – Flora and Vegetation of Asian Russia 2024 number 3

A preparation method is described in detail, which allows one to obtain defect-free cross sections of heterostructures for transmission electron microscopy and ensures the achievement of atomic resolution over a large area. The method is illustrated with examples of studying heterointerfaces of complex shape, selective oxidation, and selective etching of superlattices.

Photosensitive germanium layers on a silicon substrate have been formed by molecular beam epitaxy. The structural, optical and photovoltaic characteristics of the films have been investigated. The data obtained confirm the possibility of utilizing the developed Ge-on-Si heterostructures for the fabrication of photodetectors in the spectral range of 1.3-1.55 μm.

In this study, the electrical, morphological, and optical properties of thin aluminum films obtained by magnetron sputtering on SiON are studied. It is found that the growth of Al films on SiON follows the Stransky─Krastanov mechanism. At the stage of 3D growth, films with a cluster structure of Al grains and a pit/pore size of up to 20-50 nm are formed. For multilayer porous Al/SiON stacks, absorption of up to ~82% in the range of 1-4.2 µm and a redshift with an increase in the number of layers are observed. The analysis of optical losses of porous Al films, carried out by numerical modeling, shows the presence of optical absorption bands with a linear increase in the position of the absorption maximum λ_max at an increase in the thickness of the Al film, as well as a shift of λ_max to the long-wavelength region with a decrease in the size of Al clusters and pores between them.

We demonstrate the possibility of designing a semitransparent heater based on thin gold films. A thin 15 nm thick gold film with a surface resistivity of 3.5 Ω/□ and a transmittance in the visible range of 0.4 is deposited on a quartz substrate by pulsed laser deposition. The maximum heating temperature of the semitransparent heater is 113 °C at an applied power of 1.2 W. When a voltage is applied, the heating rate varies between 1-2 °C/s, and the rate rapidly decreases as the temperature approaches a steady state.

Using the catalytic chemical vapor deposition method, VACNT arrays with a height of 25 to 100 μm and a resistivity of 1.5 to 4 Ohm ⋅ cm have been grown for the first time on a Si/HfO₂/Fe surface. The growth of VACNTs on hafnium oxide is observed in the temperature range T = 625-725°C, but is not realized at T ≥ 750 °C. In this case, the temperature dependence of the VACNT growth rate is characterized by a value of ~1.5 eV. Using high-resolution scanning electron microscopy and Raman spectroscopy, the dominant presence of nanotubes with diameters from 1 to 10 nm in the array is shown. It is found that nanocrystallization of HfO₂ during annealing of substrates complicates the SEM analysis of catalytic Fe particles whose size on the surface of the initial amorphous HfO₂ is 2-5 nm.

The manuscript considers fundamental research in the field of nanomechanics of corrugated semiconductor nanomembranes composed of strained heterostructures. The results of a study of the magnetotransport of a two-dimensional electron gas in a corrugated nanomembrane made of a GaAs/InGaAs heterofilm are presented.

The results on the miniaturization of silicon-on-insulator (SOI) structures and SOI elements of integrated circuits (IC) are presented. To increase the IC performance, it is necessary to increase barriers and pulling electric fields due to high-k dielectrics and nanoscales, which lead to a noticeable decrease in the mobility of charge carriers with a decrease in the channel length and thickness. This, along with an increase in leakage due to source-drain tunnel currents, limits the physical length of the channel to 10 nm even when replacing silicon with two-dimensional (2D) materials such as graphene and metal dichalcogenides [1]. Three-dimensional (3D) integration in the form of double-gate transistors with complete depletion in SOI structures with a high-k buried dielectric (h- k BOX), in the form of the so-called fin transistors (FinFET) with two to four (gate-all-around ─ GAA) gates and channels of nanowires (NW FET), nanosheets (NS FET), nanoforks (FS FET), 2D materials and their 3D packaging allows one to increase the number of transistors on the chip, but not their performance. As an alternative, the option of increasing the functionality of the elements is considered, by replacing dielectrics in capacitors and transistors with ferroelectrics, and resistors with memristors, which leads to a transition from binary to neuromorphic logic, as well as to the implementation of the principles of radiophotonics, quantum devices, and sensors with parallel processing. A dynamically adjustable threshold and polarization of the gate ferroelectrics of complementary MOSFETs in heterosystems on a chip (SoC) will preserve ultra-low power consumption.

A strong response of nanosystems to the action of weak microwave power through the gap between the sample and the end of the coaxial cable from the microwave generator is detected by measurements at 4.2 K of the conductance of a short-channel p-type silicon transistor, as well as samples with a short quantum point contact in a two-dimensional electron gas of GaAs/AlGaAs heterostructures. The conductance response is gigantic in the tunnel regime of the devices; outside this regime, the sign of the microwave photoconductance depends on the mesoscopic state of the sample and the gate voltage interval under study. The mechanism of the discovered effects is elucidated by modeling mesoscopic transport within the framework of single-particle quantum mechanics and the Landauer formula, as well as by analyzing the basic circuits of electrical control of the semiconductor device. The main reason for the response of nanosystems to microwave exposure is found to be forced in-phase charge oscillations in contacts to the semiconductor due to capacitive connections in the near metallic environment of the sample.

Local anodic oxidation (LAO) of the Si(111) surface in the contact mode of an atomic force microscope (AFM) is studied depending on the relative humidity of the ambience - (35-75)% at two potentials U (-8 and -10 V) applied to the AFM probe. It is shown that LAO for U = -8V is realized at Θ ≥ 40% in the absence of growth of oxide lines in width; at U = -10V, their height and width increase linearly over the entire range of Θ values. Based on a detailed analysis of LAO and the deviation of the cantilever during the approach and retraction of the probe from the surface with variation of Θ without voltage on the probe, taking into account literature data for the semi-contact mode of AFM operation, a generalized model of the dependence of the LAO process on U and Θ is proposed.

This paper presents the results of a study of the structural and optical properties of arrays of (111)-oriented GaP nanowires (NWs) and single NWs using Raman spectroscopy and atomic force microscopy (AFM). GaP NW arrays are grown on a (111)-Si substrate by self-catalytic growth via the vapor-liquid-crystal mechanism. Single GaP NWs are mechanically transferred onto a gold surface. Transverse (TO), longitudinal (LO), and surface (SO) optical phonon modes are observed in the Raman spectra of GaP NWs. Surface-enhanced Raman scattering by optical phonon modes in GaP NWs near a gallium droplet is detected, due to the localized surface plasmon resonance in the droplet. Raman maps for GaP NWs recorded on various scattering geometries are obtained. The Raman enhancement factor for GaP NWs with a diameter of 104 and 60 nm reaches values of ~11 and 6, respectively.

The paper presents the results of a study of scanning irregularity in an optical interference microscope, performed both by a micrometer stage and a piezoceramic actuator. Registration of interference during the scanning process was carried out with a high-speed digital video camera, which allowed us to register the interference signal in detail. The obtained scanning results show the non-uniformity of the distances between adjacent interference fringes along the reference axis ─ the frame number. The procedure is presented that significantly decrease the value of non-uniformity. Application of such procedure allows to form a metric scale along scanning axis which can be used at performing high accuracy interference measurements of surface microrelief.

The paper presents results of identification of acoustic emission signatures of processes occurring during direct laser melting. As part of the experimental study, samples from the powder alloy EP 648 are grown in various modes with simultaneous recording of acoustic emission signals. Based on the results of the analysis of the registered signals parameters, their characteristic distribution patterns are formed during laser melting of defect-free and defective samples.

This paper proposes solutions that increase the efficiency of parallel program execution on high-performance computing systems when simulating heteroepitaxial growth on multiprocessor systems with shared memory. The developed algorithms are oriented towards the execution of program implementation of simulation of heteroepitaxial growth on multiprocessor NUMA nodes with shared memory. The primary prerequisite for the effective execution of parallel programs on the resources of a multiprocessor node is the incorporation of an architectural approach to the implementation of algorithms for data transfer through the shared memory of NUMA nodes. The proposed algorithms for optimizing synchronization in shared memory systems enhance the efficiency of accessing the shared memory of a multiprocessor node and reduce the time required for barrier synchronization. The developed methods and algorithms are implemented in the form of software for multiprocessor NUMA nodes with shared memory.

The influence of the main hydrochemical parameters, ionic and elemental composition of natural waters with different anthropogenic loads on the efficiency of photocatalytic processes is investigated for the oxidation of model organic pollutants: azo dye (methyl orange, MO), phenothiazine dye (methylene blue, MB). Comparative studies of water quality in two small rivers located within the boundaries of Khabarovsk (the Krasnaya River) and beyond (the Polovinka River) from April to October 2023 were carried out using the methods of chemical analysis, mass spectrometry with inductively coupled plasma and spectrophotometry. It was shown that the highest concentrations (>5 mg/dm³) were observed for ions (HCO₃^-, Cl^-, SO₄^2-) and elements (Na, Ca) in rivers draining urban areas (large highways, industrial enterprises, residential areas) and suburban territories (agricultural lands, country house areas). The efficiencies of photocatalytic destruction of anionic (MO) and cationic (MB) model pollutants dissolved in distilled water, water from small rivers, distilled water in the presence of Na⁺, HCO₃^-, Cl^-, SO₄^2- ions were compared. The time of photodestruction was assessed for model pollutant transformation degree equal to 90 % at the final stage of photocatalytic experiment. The degree of reduction in the efficiency of photocatalytic processes when conducting experiments in waters from small rivers was assessed with respect to the experiment in distilled water. The time of photodestruction of samples from real water bodies (at the degree of pollutant transformation 90 %) was demonstrated to increase with respect to the experiment in distilled water by a factor of 4.8-7.3 (MB) and 1.9-4.7 (MO) for the samples from the Krasnaya river, 3.7-6.3 (MB) and 1.1-2.2 (MO) for the Polovinka river. Value scattering was due to the seasonality of sampling.

A compacted matrix of boron carbide has been infiltrated by molten aluminum. It is shown that under the external mechanical action on aluminium, presumably simplifying the destruction of oxide film on molten metal, the temperature of boron carbide wetting decreases from 1100-1200 to 830-850 °C, and this prevents the formation of unfavourable aluminium carbide that could worsen the mechanical properties of composite material. Dense ceramic composites with the density within the range of 2.45-2.58 g/cm³, Vickers hardness up to 21 GPa and fracture toughness at a level of 3.5-4.5 MPa · m^1/2 have been obtained. It has also been determined that, although carbon nanotubes react with molten aluminium, a considerable amount of them is preserved during infiltration at temperatures below 950°С, which allows one to synthesise the соmposite material reinforced with nanotubes.

Traditional and new methods of the production of ammonium sulphate and complex salts based on it are considered. The problem related to the sales of many wastes and by-products of metallurgical enterprises, in particular technical-grade ammonium sulphate formed in the by-product coking department of JSC ArcelorMittal Temirtau that could become the secondary raw material basis to manufacture marketable products, has not been solved yet. Alternative methods of obtaining ammonium sulphate from industrial, agricultural and animal farm wastes are presented, along with various areas of its application. Relevance of the production of complex salts based on ammonium sulphate and the possibility to increase its consumption in agriculture by obtaining complex salts with decreased acidity and increased content of useful components are demonstrated. The new possibilities of sulphate ammonium application and the potential of its application as a reagent for the production of anhydrous sodium carbonate and ammonium hydrofluoride are proposed.

A technology for thermolytic processing of fuel oil over a tin-lead melt in a flow-type reactor is proposed. Methods for fuel oil processing at oil refineries are currently too complicated and cost-demanding, so the development of effective technologies for fuel oil processing is an urgent task. The main advantages of the proposed technology are rather low process temperature and pressure close to atmospheric. The technological parameters of the process are constant over all points of the reactor, which ensures high-quality products. The formation of carbon deposits on the reactor walls is essentially eliminated. The technological process occurs simultaneously with auxiliary and transport operations, which increases the productivity of the installation. It becomes possible to completely automate technological process, eliminating the use of manual labour and simplifying installation maintenance. A schematic diagram of the flow-type installation is presented. The results of experiments on the thermal cracking of fuel oil over a tin-lead melt, carried out using two versions of destructive distillation, are presented. The first version involves minimal withdrawal of thermal gas oil (31 %), while in the second version it is maximal (77 %). It has been shown that the content of gasoline fraction (b.p.-180 °С, where b.p. is initial boiling point) and diesel fraction (180-360 °С) in the thermal gas oil obtained according to the second version is lower than that obtained according to the first version. Thermal gas oils have a high content of aromatic compounds, which makes them a promising raw material for the production of needle coke.

The modern market of paint and varnish materials is represented by a wide range of construction products, including those designed to protect facades of buildings and structures from atmospheric impact. Among the variety of varnishes and paints for processing and rendering decorative and protective properties to building materials, as well as from the viewpoint of environmental friendliness, the most popular products are water-dispersion paints based on acrylic dispersions. However, along with the high values of colour fastness, UV resistance and gas permeability, acrylic-based paints are insufficiently elastic and lack resistance to water. In this regard, the paper considers a method for increasing the mechanical and hydrophobic properties of acrylic paint and varnish material by introducing a hydrophobic polyethylhydrosiloxane-based emulsion containing polyethylhydrosiloxane (PEHS) - 35.20, glutaric aldehyde - 0.19, polyvinyl alcohol (PVA) - 7.75, water - 56.86 wt%, as well as by increasing the surface development (relief), achieved by increasing the volumetric concentration of pigments (VCP). The optimal range of the amounts of a hydrophobic emulsion and a coalescent into the composition of water-dispersion paints based on acrylic dispersion has been determined. To assess the stability of the coating after drying of an aqueous dispersion paint modified with the aqueous polyethylhydrosiloxane emulsion, the wetting angle and free energy of the surface were evaluated using two liquids of different polarities, namely distilled water and diiodomethane. The possibility of modifying the aqueous dispersion paint, characterised by VCP of 70-80 %, by the polyethylhydrosiloxane hydrophobic aqueous emulsion in the amount of 5-5.5 %, combined with ethylene glycol (4.5-5.5 %) has been established, which makes it possible to obtain a hydrophobic coating with a wetting angle of up to 100°. By comparing the wetting angle values of the coatings, it has been shown that in the absence of the hydrophobic additive, this parameter is lower by 12.5 % than the parameter of the modified sample.

Despite the increasing contribution of integrated approaches to processing waste from the forest industry and crop production, the main method of recycling plant wastes is still combustion, which leads to losses of valuable substances. An alternative and advanced way of plant waste processing is extraction to obtain useful substances. The previously published data on the extraction-based methods to isolate valuable substances from wood waste and straw of various crops under industrial and laboratory conditions are generalised in this work. The data on the chemical composition of wastes from forest industry and crop production, as well as on the content of chemical compounds of practical significance are systematised. The basic approaches to retrieve such valuable components as lignin, furfural, waxes, organic acids, polyphenols, dyes, silicon dioxide and others from plant wastes are described.

The electronic effects of xenon-containing substituents XeY, [Xe⁺] and [XeF₂⁺] in different solvents were calculated using the ¹⁹F NMR method. The results obtained allow us to classify these substituents as the strongest σ-electron acceptors due to the strong positive inductive effect, while the resonance effect is small.

2,5,5-Triethyl-2-alkynyl-3,4-bis(hydroxymethyl)pyrrolidine-1-oxyls (alkynyl = C≡CR, and R = H (2), C(Me)₂OH (1), Ph (7)) undergo cyclisation on heating with sodium hydroxide to form cyclic vinyl ethers, the derivatives of 6-methylene-hexahydro-1 H -furo[3,4-b]pyrrole-1-oxyl. A bicyclic radical derived from radicals 1 or 2 is capable of reversible addition of alcohols to the vinyl group in the presence of acids. Cyclisation of radical 7 in the acid environment in the presence of mercury acetate follows a different route, with the formation of 2,2,7a-triethyl-3-(hydroxymethyl)-6-phenyl-1,2,3,3a,4,7a-hexahydropyrano[4,3-b]pyrrole-1-oxyl.

Aldonitrones of pyrroline series are widely used in organic synthesis, in particular in the synthesis of alkaloids and other biologically active compounds, and as spin traps for short-lived radicals. A three-component domino process involving glycine benzyl ester, ketones (cyclohexanone and diethyl ketone) and fumaric acid esters was used to synthesise aldonitrones of the pyrroline series of 1-pyrroline-1-oxide. The benzyl esters of 3,4,5-substituted prolines obtained in the first step were selectively cleaved by hydrogenolysis. Oxidation of the resulting cyclic amino acids in the tungstate - hydrogen peroxide system is accompanied by decarboxylation and leads to the formation of 3,4,5-substituted 1-pyrroline-1-oxides. It is shown that the ester groups in these compounds can be reduced to hydroxymethyl ones by an excess of lithium aluminum hydride, and subsequent treatment with manganese dioxide leads to aldonitrone group recovery.

An optimised method of 1,1-difluoronaphthalen-2(1H)-one hydrodefluorination leading to the formation of fluoronaphthol under mild conditions is proposed. The palladium-catalysed process is shown to involve carbonyl reduction followed by subsequent hydrogen fluoride (HF) elimination. The structure of the intermediate product and the effect of catalyst support material on hydrodefluorination selectivity have been determined.

Chelators based on terpene bis(α-amine oximes) applied onto low-polar sorbents (coal, Sibunit, Polysorb) are effective selective extractants for the extraction of palladium and gold from acidic aqueous solutions containing the mixtures of precious metals and 3 d-elements. The use of sorbents impregnated with the new chelators allows extraction in the liquid-solid mode without using any organic solvent.

The composition of the lipophilic components of Euphorbia virgata Waldst. et Kit. has been studied. Acidic and neutral components have been identified using gas-liquid chromatography with mass spectrometric detection (GC-MS) following alkaline hydrolysis of the whole extract. The plant material was extracted with methyl tert -butyl ether (MTBE). Total acids isolated during sample preparation were analysed after methylation with diazomethane. The composition of the neutral components of unsaponifiable residue was studied without derivatisation, but after separation by column chromatography on silica gel into the groups of substances of different polarity. As a result, aliphatic acids with the chain length 10-30 carbon atoms, including unsaturated ones, were identified by comparison with databases. In addition, two compounds rarely occurring in plant materials were detected: ricinoleic and octadeca-9-en-12-ynic acids. More than 100 triterpene and aliphatic compounds of the unsaponifiable residue and 25 components of acidic fractions were identified. The hydrocarbon fraction was determined to contain, in addition to n- alkanes, also substantial amounts of unsaturated branched hydrocarbon squalene. Highly active triterpene alcohols and ketones are mainly represented by ursane, lupane and cycloartane derivatives. The main sterol component (β-sitosterol) is accompanied by cholesterol, campesterol, stigmasterol, stigmast-7-en-3-β-ol and stigmastan-3-β-ol. A substantial contribution from euphanic compounds characteristic of the plants of the Euphorbiaceae family has been revealed.

The qualitative composition of lipophilic secondary metabolites in the medicinal plant leuzea safflower ( Rhaponticum carthamoides (Willd.) Iljin) has been studied by gas chromatography - mass spectrometry. The roots and rhizomes of this plant species were used as the raw material. Hexane and methyl tert -butyl ether (MTBE) were used as extractants. Two extraction schemes were used (exhaustive and sequential), which allowed us to obtain more detailed information on the composition of components of the raw material. The obtained lipophilic extracts were separated into acid and neutral components by treating with NaOH and KOH solutions. The acid components were transformed into methyl ethers by treatment with diazomethane. The neutral components of the unsaponifiable residue were analysed without derivatisation. The fractions enriched with hydrocarbons, ketones, sterols, aliphatic and triterpene alcohols were obtained by chromatographic separation through a column with silica gel. A series of low-polar compounds were identified that have not been detected previously in this kind of raw material. By comparing the mass spectra obtained in the work with the available databases, the following compounds were identified: aliphatic acids with chain length 10-30 carbon atoms (including unsaturated and dicarboxylic), the compounds of cinnamic series, as well as benzoic, salicylic, sterculic, 9,10-octadecadienic and phenylpropanoic acids. More than 90 triterpene and aliphatic compounds of the unsaponifiable residue and 33 components of free and bound acids were identified. In addition to n- alkanes, the hydrocarbon fraction contains also squalene, as well as saturated and unsaturated hydrocarbons with shorter chains. Aliphatic and terpene aldehydes and ketones were detected. Highly active triterpene alcohols and ketones are represented mainly by ursane and oleanane derivatives. The major sterol component (β-sitosterol) is accompanied by cholesterol, campesterol, stigmasterol, stigmast-7-en-3-β-ol and stigmastan-3-β-ol.

A series of ureas containing adamantane and monoterpenoid residues has been synthesised. All compounds were tested in vitro using a pseudoviral system containing the S glycoprotein of the SARS-CoV-2 virus and infectious SARS-CoV-2 viruses of various strains on its surface. Compound 4a demonstrated high activity against four strains of SARS-CoV-2.

2-[4-(2-Methacryloyl)-piperazine-1-ylmethyl]-9 H -thioxanthen-9-one-S,S-dioxide 1, an electrochemically active monomer, has been synthesised from 2-(piperazine-1-ylmethyl)-9 Н -thioxanthen-9-one-S,S-dioxide and methacryloyl chloride. Subsequent radical copolymerisation of the synthesised compound with methylmethacrylate leads to an electroactive copolymer (PMMA-co-ThxSO₂) with the ratio of methyl methacrylate fragments in the chain to the pendant (side) groups of the 9 Н -thioxanthen-9-one S,S-dioxide structure equal to 95 : 5, respectively. It has been shown by cyclic voltammetry that the electrochemical reduction (ECR) of 1 in acetonitrile (MeCN) is a two-electron and two-stage process, with the formation of long-living radical anion at the first one-electron stage and unstable dianion at the second stage. Electrochemical reduction of PMMA-co-ThxSO₂ is due to the reductive electrochemical activity of the pendant groups, and its mechanism is similar to the ECR of monomer 1. This compound is a polymer with pendant groups that play the role of efficient electron traps during charge transport inside the thin copolymer film, and it can be used in the resistive memory technologies (ReRAM - Resistive Random Access Memory) as the active working layer of memristors.

The areas adjacent to open coal mining facilities are affected by different kinds of anthropogenic impact, including dust pollution. To reveal the extent of technogenic impact, the parameters characterising the content and composition of 19 priority polycyclic aromatic hydrocarbons (PAHs) in chernozem soils adjacent to the haul road of the Gorlovo anthracite deposit (the Novosibirsk Region) were assessed. It is shown that the maximum total concentration of PAHs (>1000 ng/g) is reached at the distance of 100 m from the source, while the levels higher than the background are detected at a distance of 1000 m. The effect of dominating wind direction and the presence of tree shelter belts were determined to affect the total PAH content in soil but leave their group composition unchanged at a distance of 2000 m from the road. At the same time, the individual composition of PAHs in soils changes with an increase in the distance from the pollution source. The concentration of benz(a)pyrene and total PAH content, calculated for benz(a)pyrene toxic equivalents, were determined in the soils of territories adjacent to the haul road and compared with the current standards in force in the Russian federation (SanPiN). Statistical processing of the results, performed by the principal component analysis, shows that the input of black carbon in the form of anthracite coal dust into soil is most adequately represented by polyarene ratio PHE/(PHE+CHR), where PHE is phenanthrene, and CHR is chrysene. However, the threshold of technogenic load (<0.8), that was previously established for objects in which anthracite is the main source of PAHs, requires confirmation for black soils.

[1]Benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives attract attention in the field of organic optoelectronics due to their stability in air, 2D film formation ability and high charge-carrier mobility. Here we present approaches to the synthesis of new furanyl-substituted BTBT derivatives. The physicochemical properties of the target compounds were studied. It is shown that all materials have high quantum yields of photoluminescence. A thorough analysis of BTBT bromination has been carried out, and the reaction conditions were optimised. It has been shown that a mixture of regioisomers is always formed in this process, but this does not necessarily interfere with further synthesis. A significant reduction in the total reaction time from 48 to 6 hours has been achieved.

Modern trends in the development of structural biology make it relevant to study the structure of biomolecules under the conditions close to natural, i.e., directly in a living cell and at temperatures close to physiological ones. One of the promising technologies that allows approaching this ideal is the targeted introduction of spin labels (for example, nitroxides), followed by investigation using pulsed electron paramagnetic resonance (EPR). Today, the greatest stability in living systems is demonstrated by sterically hindered nitroxyl radicals of the pyrrolidine series with four ethyl groups at a paramagnetic centre, but their relaxation characteristics do not allow measurements by pulsed ESR methods at a temperature above 80 K. Nitroxides with spirocycloalkane fragments surrounding the nitroxyl group are suitable for measurements at higher temperatures, but they are rapidly reduced by the components of living systems. Pyrrolidine nitroxides with two spiro-(2-hydroxymethyl)cyclopentane moieties combine high resistance to reduction with high spin relaxation times at a temperature of 120 K and above. In this work, a hydrophilic chiral radical of this series - (1 R ,5 S ,7 S ,8 R ,12 S ,13 S )-12,13-dihydroxy-1,8-bis(hydroxymethyl)-6-azadispiro[4.1.4.2]tridecane-6-oxyl was obtained and characterised by us for the first time.

The synthesis of ((9 H -(4,5-diazafluorene)-9-ylidene)methyl)arylenes is presented and their physicochemical characteristics are studied by cyclic voltammetry and optical spectroscopy. The target compounds were synthesised from commercially available reagents in three steps using a combination of Suzuki-Miyaura cross-coupling and condensation reactions. It was found that the compounds had a low photoluminescence quantum yield in solution, and 9-(4-([2,2'-bithiophen]-5-yl)phenylidene)-9 H -4,5-diazafluorene demonstrates aggregation-induced luminescence. The crystal structure of 9-(4-([2,2'-bithiophen]-5-yl)phenylidene)-9 H -4,5-diazafluorene was solved by X-ray diffraction analysis. The single crystals of this compound have the elongated plate morphology and exhibit photoluminescence quantum yield of 5 %.

On the territory of the Tomsk Region there is a group of species that have isolated locations, low numbers, are characterized by a narrow ecological amplitude and are located on the border of their range. However, they do not have conservation status and require additional research. In this regard, studies were carried out on three local cenopopulations of Nepeta nuda in the south of the Tomsk Region. N. nuda is a Eurasian meadow-steppe species. This is a perennial herbaceous taproot sympodially growing polycarpic plant with an elongated erect shoot, a hemicryptophyte. For the studied species, the phytocenotic location was established, the seasonal rhythm of development, morphological parameters, ontogenetic structure and seed productivity were studied. The influence of the anthropogenic factor on the stability of a rare species in natural habitats was studied. It has been established that the northern boundary of the species’ distribution lies in the south of the Tomsk Region (Kozhevnikovsky district). The habitats of the species are limited mainly to moderately steep and gentle slopes of southern exposure, occupied by steppe meadows. The species was recorded as part of forb-grass, forb-reed grass and forb-sedge plant communities. The floristic composition of phytocenoses with the participation of N. nuda is quite depleted and is represented by 18-30 species. The density of N. nuda individuals in the surveyed areas remains quite low, varying between 1.38-3.50 individuals/m². The ontogenetic composition of cenopopulations is characterized by incompleteness: there are no individuals at the initial stages of ontogenesis or, in general, this group is poorly represented. Also, no individuals in the senile state were found in any of the coenopopulations. The main way to renew and maintain the number of species in nature is seed propagation. However, due to significant damage to fruits and seeds by insect pests, the seed productivity of the species, according to some indicators, is reduced by more than half. Seed germination remains below average. There is no vegetative propagation. As a result of the data obtained on the distribution and state of coenopopulations of N. nuda in the south of the Tomsk Region, we consider it necessary to recommend this species for inclusion in the next edition of the Red Book of the Tomsk Region with rarity status 3 - a rare species, on the border of its range.

The influence of natural and anthropogenic factors on the anatomical structure of the chlorenchyme of leaf blades, as well as glumes of spikelet and flower at generative shoots of Koeleria pyramidata , Poa angustifolia , Agropyron cristatum and Bromus inermis (Poaceae) was studied. On the example of Koeleria pyramidata and Agropyron cristatum the comparison of the growing conditions, differing in precipitation and pasture load was carried out. At Poa angustifolia and Bromus inermis the effects of trampling were considered. The mesophyll of the leaves of Koeleria pyramidata and Poa angustifolia is composed of cells of simple shape, the chlorenchyma of the leaf blades of Agropyron crispatum and Bromus inermis , as well as the glumes of spikelet and flower of all species are made of cells of complex shape. At the same time in different habitats, the main features of assimilative tissue organization are preserved. For the leaves of Koeleria pyramidata , the possibility of restructuring the mesophyll structure in the conditions of a dry mountain steppe in comparison with a steppificated meadow was shown - from ventrodorsal to isolateral-palisade, close to isopalisade. In other species, the structure of the mesophyll of leaf blades is preserved in different habitats. Ecological adaptations of chlorenchyma of festucoid grasses to unfavorable growing conditions are mainly associated with a decrease in the height and thickness of assimilative cells of simple shape and sections of cellular cells, with their compaction, while a tendency to simplify the spatial configurations of cells of complex shape appears.

The presented work contains the results of studying the floristic diversity of vascular plants in protected mires in the mountain part of the Sverdlovsk Region (Russia). The studies were carried out on six peat six mires: Shitovskoe, Malinovskoe, Paklinskoe, Moroshechnoe, Severka, Shaitanskoe. The article provides a list of discovered species of vascular plants. In total, 170 species of vascular plants, 10 subspecies and 3 hybrids belonging to 104 genera, 47 families, and 5 divisions were identified in the flora of the studied mires. The leading families in terms of the number of species are Cyperaceae (27 species), Rosaceae (15 species) and Ericaceae (12 species), the leading genera are Carex L. (21 species), Salix L. (9) and Rubus L. (6). A relatively low level of species similarity between the floristic lists of bogs under consideration was revealed. The greatest similarity was noted for the Paklinskoye and Severka mires. Рlurizonal and boreal species with a wide distribution (Holarctic, European-West Asian and Eurasian) dominate in the flora. Among the biomorphological groups, polycarpic herbs are of significant importance (63 %), of which 39 % are rhizomatous plants. In the studied mires, cenopopulations of some rare species included into the Red Data Book of the Sverdlovsk Region were revealed: Juncus stygius L., Corallorhiza trifida Châtel., Nymphaea candida J. Presl et C. Presl, Hammarbya paludosa (L.) Kuntze, Dactylorhiza incarnata (L.) Soó, Dactylorhiza maculata subsp. fuchsii (Druce) Hyl., Goodyera repens (L.) R. Br., Malaxis monophyllos (L.) Sw. and Neottia ovata (L.) Bluff et Fingerh.

Bed-load yield was estimated for 60 river cross-sections flowing into the Pacific Ocean, the Bering Sea and the Sea of Okhotsk in the Kamchatka krai territory on the basis of N.I. Alekseevskii method developed for bed-load transport assessment by the movement of five types of bottom ridges during floods and low-water periods. For 398 unstudied rivers bed load was assessed by the relationship between specific bed load yield and basin area. Estimates of the specific bed-load yield for the rivers studied show that the highest values are observed in rivers with a relatively small catchment area, often characterized by a mountainous or semi-mountainous type of channel with a pebble-boulder composition of channel sediments. Specific bed-load yield significantly decreases with increasing catchment area and with the transition from mountainous/semi-mountainous to plain sections of rivers. The total mean annual bed load yield is estimated at 18 mln t per year, and it exceeds suspended sediment yield by a factor of 1.5. A spatial analysis of bed load variability is made for the Kamchatka River basin. It was found that bed load is larger in eastern tributaries of the river draining areas of active volcanism in Kamchatka. Variability in bed load along the Kamchatka River shows a decrease in its proportion in the total sediment yield from the source to the mouth due to the channel changes from mountain to plain type. It has been demonstrated that for some mountain rivers with a pebble and pebble-boulder sediment composition, the share in the total sediment yield can approach 100 %. It decreases to 40-70 % in semi-mountain rivers. The share of bed-load material in the total sediment yield reaches its minimum values in large lowland rivers and is about 13-20 %.

This outlines the issues related to inventory, evaluation and monitoring of biodiversity, based on mapping as a developing independent research direction that allows for the spatial analysis of biota based on using a wide range of thematic maps. Examples of identifying biota diversity are considered using the cartographic method at four main levels: species richness of concrete (local) floras, phytocoenotic diversity (species richness and diversity of communities of vegetation formations), natural complexes (landscape biodiversity), and ecosystem diversity. A short historical overview of the gradual formation of theoretical and methodological principles of biodiversity mapping is given. As a result of these principles, hundreds of maps have been prepared to date, reflecting the diversity of organisms based on different approaches and methodological principles. There are maps of the floristic and faunistic diversity of the world (isoline diagrams connecting points with the same quantitative indicators for assessing the levels of floristic and faunistic species richness of a certain area); maps on a grid (raster) basis (the use of cells of a certain area with marks of presence-absence of a species or a complex of species in each of the cells); maps compiled on the basis of modeling the number of taxa depending on environmental conditions (modeling method by ecological parameters), and maps of phytocenotic diversity. Examples of the successful application of Earth remote sensing data and, above all, satellite images are shown for the creation and use of multi-scale maps that have new prospects in biodiversity studies. In the final part of the paper, an ecological-geographical approach to the identification and assessment of biodiversity has been considered. Its prospects are related to the study of biodiversity within the natural boundaries of biotic cover units of different levels on the basis of ecological units of biosphere subdivisions - regional biomes. This approach is of particular importance in the study of fundamental problems of the biodiversity geography of mountain areas.

The aim of this article is to explore the experience of applying environmental rhetoric in the political and economic discourse of the 1920s when Soviet Russia was forced to resort to the concession of national raw material resources to foreign entrepreneurs. In particular, foreigners were granted the right to exploit northern forests, and fish and sea animals in the Arctic Ocean. The sources for the study were diverse historical materials, both published and various business correspondence of Soviet political and economic bodies, often classified as secret. The analysis of the totality of sources allows us to reconstruct one of the early pages of domestic environmental science using the example of the protection of the country’s natural resources, which was initially a response to various challenges of the era. Thus it was found that, before the 1917 Revolution, environmental protection issues influenced political decisions and public sentiment as a form of struggle against foreign economic competitors. In the 1920s, arguments for the protection of natural resources were widely used by the authorities in the northern provinces of European Russia, seeking to preserve traditional occupations for the local population. Later, in order to close down foreign concessions that proved unable to achieve the results expected of them, issues of inefficient and even predatory use of natural resources began to be raised by the central authorities. To substantiate these claims, experts in various fields of science and practice of natural resource use were involved, and this gave an impetus to the development of environmental science. In addition, the activities of concessionaires were subjected to constructive criticism by Soviet economists, which made it possible to identify ways in which the national raw materials economy began to develop independently.

This article provides a review and retrospective analysis of legal regulation of economic activities in the Baikal Natural Territory. An assessment and critical vision of the current issues of regulation of economic activities, use and protection of natural resources in the period of planned economy, in the period of post-perestroika and at present. It is emphasized that without proper scientific substantiation, laws can lead to irreversible changes in ecology and economy, and legal conflicts, which were illustrated by specific examples of modern practice. It is pointed out that significant restrictions for the development of economic activities, caused by the special regime of nature management in the Baikal Natural Territory, generally restrain economic, social and demographic development of the region. The results of the latest censuses after the beginning of economic reforms show a consistent trend of population and labor resources reduction throughout the entire Baikal natural territory. The article shows the directions of improving the tools of legal regulation of economic activities. It is proposed to use the mechanism of rent relations and the resulting rent effect in obtaining super-profits through the sale and use of the cheapest electricity in the country as well as to improve environmental legislation in terms of compensation for environmental damage. It is concluded that many environmental documents are outdated and require clarifications and additions, first of all, on the issue of regulating the level regime and bringing it closer to the natural state. The authors propose to optimally regulate the relationship between nature and society by nature-like technologies, which are maximally embedded in ecological systems.

The world’s largest Antarctic ice sheet has a significant influence on the formation and variability of climate, the system of circulation of oceanic water, biodiversity and surface and subglacial lakes of this region. Appearance of the water strata of land hydrology bodies of Antarctica is usually connected with the processes of snow and ice melting. In the case of subglacial lakes this process occurs on the glacier bed under the influence of thermal isolation of the geothermal flow by a large ice strata, energy of friction forces due to the movement of the glacier over bedrocks and large pressure values, which allows melt water to accumulate in hollows of the subglacial relief. In the case of Lake Vostok, however, the genesis of its water body is connected with accumulation of atmospheric precipitation and discharge of ancient rivers that existed on this continent at the time of its location in the temperate climatic belt before the epoch of its glaciation, i. e. before the beginning of formation of one whole continental glacial cover. We distinguish the layered structure of the glacier above Lake Vostok explaining the genesis of all layers by different stages of glaciation of the sixth continent. Analysis of geological, geophysical, glaciological and biological studies in the area of location of the valley of Lake Vostok convincingly proves that the water body of this subglacial lake existed on the surface before the onset of multiyear glaciation of Antarctica while the glacier has only a role of the cover isolating the water body. This conclusion is confirmed by the results of numerical modeling of the processes of glacier freezing/melting proving that the lake water strata could never freeze through to the bottom due to water adfreeze at the glacier bottom surface. Thus the water body and bottom sediments of Lake Vostok are more ancient natural bodies than the Antarctic ice sheet.