bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional Missile Defense Architecture of the US and Their Partners In the Western Pacifi Security
Authors: Krivolapov Oleg O.
Published: April 2024

China has the largest arsenal of missiles with a range of less than 5,500 km. In 2019, the US withdrew from the INF Treaty and decided to deploy the same kind of missiles in East Asia. At the same time Washington plans to strengthen the theater missile defense architecture in the region. The purpose of the article is to determine the potential impact of missile defense strengthening by the US and their partners in East Asia on regional security. It is necessary to understand the prospects of the situation, given the presence of several hotbeds of potential conflict in the Western Pacific. A critical analysis of the expected actions of China and the US in the region, the role of regional missile defense systems in those scenarios, and both sides’ doctrines of non-nuclear missile use is provided. In certain situations, an enhanced theater missile defense could help the US and their partners to strengthen regional deterrence, but not in all situations. The analysis of both sides’ doctrinal provisions help to understand how strengthening the regional missile defense by the US and their partners can destabilize the situation. It is concluded that theater missile defense, unlike arms control measures, is not a reliable tool for ensuring regional stability.
Communication problem in risk society: challenges of the media reality
Authors: Kukarnikov Dmitriy G. , Garshin Nikolai A.
Published: April 2024

Philosophical foundations for the analysis of social communication within the risk society are studied. The development of media and the multiplication of risks in modern society, multiplied by the impact of the pandemic, impact communication in the modern world. Both positive and negative aspects of the impact of technology on communication are revealed. The influence of the deformation of tolerance on various social structures is studied, based on the works of Russian and Western philosophers (representatives of the Frankfurt School in particular). It is concluded that critical attitude to one’s actions is extremely important today both in the real world and in virtual space, since consequences of carelessly expressed ambiguous opinions or actions can cause unpredictable consequences.
Public Opinion in Armenia on the Greater Russian Space Before and After the Second Karabakh War
Authors: Manukyan Samvel A.
Published: April 2024

The problem of Armenia’s geopolitical choice in the context of world-system analysis and the history of Armenia in the 20th and early 21st centuries is considered. It is concluded that geopolitical configuration in Transcaucasia today and 100 years ago are similar, and said similarity determines an adequate geopolitical choice for Armenia in modern conditions - integration with the Greater Russian space. The dynamics of attitudes in Armenian society towards Russia as the best ally of Armenia, and France as the main competitor of Russia during 2011-2022 is given. In this context, the impact of the 44-day Karabakh war on attitudes towards the Greater Russian space is estimated. The analysis is based on two indicators - the attitude towards the USSR and the attitude towards Armenia’s accession to the Union State of Russia-Belarus. The systems of argumentation of supporters and opponents of the USSR are identified, as well as their transformation after the 44-day war and the factors influencing the attitude of society towards the Greater Russian space. Armenian society was segmented into pro-Russian, pro-Western, mixed, and not having an accentuated orientation sectors. An assessment of the sizes of these segments, as well as a comparative analysis of their main characteristics was carried out. These characteristics include (but not limited to): the level of loyalty to the country’s political course, electoral participation, information preferences, trust in state and public institutions. The presented empirical material was obtained by secondary analysis of the databases of nationwide representative sociological surveys “Caucasian Barometer” for 2011-2022, carried out by the Caucasus Research Resource Centers. The results of other sociological surveys are also presented.
Constructivism and primordialism: complementary methodologies in ethnology and sociology
Authors: Pain Emil A.
Published: April 2024

The stereotype established in the post-Soviet ethnological and sociological theory is revised. The stereotype contrasts two methodologies: constructivism, on the one hand, and primordialism, on the other. The first approach is considered correct, the second - false. The combination of these methodologies is regarded to be impossible. The opposite idea that both approaches are complementary in the analysis of different aspects of socio-cultural reality is proposed. The author's interpretation of the three named methodologies is given. An attempt is made to accurately and succinctly characterize methodological positions of such classics of the theory of nation and ethnicity as B. Andersen, and E. Gellner and E. Hobsbawm.
Gender gap in the federal government authorities under conditions of the rising economic role of women in modern Russia
Authors: Brushkova Lyudmila A.
Published: April 2024

Issues related to the gender gap in the federal government authorities of Russia are discussed. It is emphasized that Russian women are alienated from “big politics” despite the fact that women have more substantial (compared to men) human capital. This contradiction should be resolved through extension of women’s representation in government bodies of various levels and especially at the federal level, taking into account the highly centralized nature of political power in Russia. The gender pyramid of power (the higher is the power level the lower is women’s representation) was built in the Soviet time and is reproduced in modern Russia without essential modifications. Nevertheless currently the gender structure of economy management is changing women take part in entrepreneurship and management of companies, including the top-management level, more actively. It is concluded that the gender-balanced economy is gradually established in Russia, and it will require more active and responsible participation of Russian women in the political sphere. Non-commercial organizations and public movements, that are efficient enough nowadays in Russia, can be a means of women’s political mobilization. The article is based on the data of the Federal State Statistics Service of Russia (Rosstat) and the World Economic Forum.
Gender aspects of the civilizational approach (new horizons of interdisciplinary research)
Authors: Ilinskaya Svetlana G. , Sirina Ekaterina A.
Published: April 2024

The problems of interdisciplinary research in social sciences and the inseparability of the ideological component from socio-political knowledge, which largely contributes to the crisis of the social sciences, are analyzed. Also considered are the issues of the narrowness of a strictly disciplinary approach in social sciences, insufficient preliminary articulation of ontological foundations in socio-political studies, as well as the low demand for fundamental elaboration in applied disciplines, leading to their gradual transformation into “secret knowledge” with its own special language inaccessible for the “profane majority”. The authors debate with the position of political philosopher B.G. Kapustin on the problem of interdisciplinary and the concept of “civilization”. It is argued that the opponent contradicts his own definition of interdisciplinary when he considers “civilization” as a “worldview construct”, because the local-civilizational approach per se is a classic example of interdisciplinary research. The debate with liberal feminism is also presented. This field non-reflexively dominates Russian gender studies to such an extent that it leads to a shift in priorities and loss of “common sense”. A critical analysis of its main postulates, which have remained virtually unchanged despite historical changes, shows that interdisciplinary approach makes it possible to solve practical problems facing society based on a synthesis, for example, of civilizational and gender approaches.
Problems and prospects of the development of social and human sciences in the system of scientific knowledge
Authors: Agamirova Elizaveta V. , Zharova Elena N. , Malakhov Vadim A.
Published: April 2024

For many years the humanities have been in the shadow of natural and technical sciences. A significant share of funding - both budgetary and non-budgetary - is distributed in favor of natural and technical sciences, while social sciences and humanities account for only about 5% of funding. Grants provided by the Russian Science Foundation are largely aimed at supporting projects in the field of natural and technical sciences. Currently, there is a need to modernize approaches to research support by redistributing priorities in favor of cross-disciplinary studies (cognitive research, digital technologies, life and social sciences, digital humanities, etc.). The problems of social sciences and humanities are identified based on an integrated analysis of data in the field of natural and social sciences and humanities in the next areas: internal costs of research and development, sources of research and development funding, grant support for research projects by the Russian Science Foundation, and human resources capacity. Economic and statistical methods, as well as methods of grouping and comparative retrospective analysis are used. The data of the Organization for Economic Cooperation and Development (OECD), The UNESCO Institute for Statistics, the Federal State Statistics Service (Rosstat), as well as reports of the Russian Science Foundation (RSF) served as the information base for the analysis. The key directions of development of social sciences and humanities are proposed on objective analytical conclusions about the need to intensify support of interdisciplinary scientific research within the framework of state programs of scientific and technological development. The results of the study can be used by public authorities of the Russian Federation in elaborating program documents aimed at the implementation of the state scientific and technological policy.
The right to science in the context of the deformation of the international law-order under sanctions
Authors: Shugurov Mark Vladimirovich , Pechatnova Yulia Vadimovna
Published: April 2024

The paper assesses restrictive measures in the field of international scientific cooperation. The authors consider unilateral sectoral «science sanctions» as a large-scale phenomenon in modern international relations; analyze how the internationally recognized human right to science is ensured under sanctions conditions; substantiate a new direction of human rights activities. It is concluded that anti-Russian restrictive measures in the field of international scientific cooperation violate the basic right to science. The conclusion is formulated that scientific institutions become active subjects of extraterritorial violations of this right. The complication of the sanctions regime in the scientific sphere, including the introduction of horizontal and vertical restrictive measures, indicates the use of science for geopolitical purposes. The novelty of the study lies in the conceptualization of the deformations of the international legal order in the field of human rights as a result of the negative consequences of unilateral restrictive measures in the field of science.
Calculation of Radiation-induced DNA Damage Efficiency. Analysis of Uncertainties
Authors: Eidelman Yu. A. , Salnikov I. V. , Andreev S. G.
Published: April 2024

Computer simulations of the DNA damage are widely used due to their large application area. The computational methods to predict DNA breaks are based on molecular concepts about the formation of breaks, the geometric structure of DNA, as well as information about the distribution of absorbed energy in a DNA mo-lecule. Since the calculations use different postulates and algorithms, it is often difficult to make intercompa-rison between theoretical results in the literature. Due to the spread of experimental data on DNA breaks, the determination of parameters of DNA lesion models from the data is not straightforward. In this paper, a comparative analysis of two basic models of DNA structure, molecular and enlarged subvolume, various schemes for the formation of single- and double-strand DNA breaks, as well as different classifications of the break complexity after irradiation with protons and α-particles is performed. Numerical results on initial radiation-induced DNA damage due to direct and quasi-direct action demonstrate the dependence on variation of model parameters. The parameter values where the two models agree or differ are discussed.
3D Simulation of Electronic Exchange between an Atomic Particle and a Defect-Containing Surface
Authors: Klimov N. E. , Gainullin I. K.
Published: April 2024

The electronic exchange between an atomic particle (a charged ion or a neutral atom) and a metal surface containing a defect in the form of an atomic step has been studied. The research tool is three-dimensional computer modeling. A model static problem is considered when the particle is fixed above the surface. Calculated data are obtained on the dependence on the distance to the surface and the lateral position of the particle of the main parameters of charge exchange: the energy position and the width of the particle level (which determines the efficiency of the electronic exchange).
Depth Distribution of Radiation Defects under Ion Irradiation of Silicon
Authors: Novikov N. V. , Chechenin N. G. , Shirokova A. A.
Published: April 2024

The defect distribution density reaches its maximum at a depth that depends on the energy and mass of the ion. This depth decreases with increasing angle of incidence due to multiple scattering of primary ions in the surface layers of the target. As the ion mass increases, the maximum defect density increases according to a power law. The asymmetry of the maximum in the depth distribution of defects is associated with an increase in the elastic energy loss during ion stopping and a decrease in the ion transmission coefficient with increasing layer depth.
On the Dynamics of Development and the Results of the Action of Electric Discharge in the Aquatic Environment
Authors: Khlyustova A. V. , Sirotkin N. A. , Agafonov A. V. , Stepovich M. A. , Shipko M. N.
Published: April 2024

The properties of the synthesized nanostructured materials are determined by the methods of their preparation. The combination of electric discharges with liquid is one of the new tools for the synthesis of pure structures but the conditions for obtaining structures play an important role as in the case of traditional synthesis methods. In this work, the electrical and emission characteristics of a low-temperature direct current plasma in contact with water at currents of 0.25 and 0.80 A are studied. The values of the power (energy) of single discharges are calculated. It has been established that this type of discharge burns in a pulsed mode. The value of the discharge current affects the frequency of occurrence of discharges and the energy of an single discharge. It is shown that low-temperature underwater plasma is an effective tool for the synthesis of nanocomposites based on metal oxides, the precursors of which are metal electrodes. The emission spectroscopy method was used to study the emission spectra of underwater plasma. The sputtering of electrodes during plasma combustion, has been established. X-ray phase analysis showed that the phase composition of the obtained products is determined by the strength of the plasma current. The formation of oxides and hydroxides of Ni and Cr with different valencies of metal ions was found.
Comparison of the Results of Simulation and Measurements of Interferograms of Coherent Transition Radiation
Authors: Shkitov D. A. , Toktaganova M. M. , Naumenko G. A. , Shevelev M. V.
Published: April 2024

The results of a comparison of the autocorrelation functions of coherent transition radiation obtained experimentally on the microtron of the Tomsk Polytechnic University and by simulation methods are presented. The conditions of the experiment and the mathematical basis of the simulation are described in detail. Comparison of experimental and simulated data have shown good agreement. It is demonstrated that the autocorrelation function of the transition radiation depends on the temporal structure of the electron beam and can be used as a precision method for measuring the delay time between electron bunches.
Spectroscopic and Kinetic Investigations of the Permeability of the Surface Layers of Membranes in the Process of Microfiltration Separation of Water-Organic Solutions
Authors: Konovalov D. N. , Khorokhorina I. V. , Lazarev S. I. , Nagornov S. A. , Kornev A. Yu. , Kotenev S. I.
Published: April 2024

IR spectroscopy was used to study the structure of the surface layer of air-dry, water-saturated and working samples of microfiltration composite membranes MMK-0.45 and MFFC-2G based on polyamide and fluoroplast, respectively. IR spectra were analyzed in the frequency ranges 500–1700 and 2800–3400 cm–1. In the case of the polyamide membrane, the main peaks of the functional groups of polymers in the IR spectra of dry, water-saturated, and working samples coincide. The absorption bands of polyamides range from 650 to 5000 cm–1, corresponding to the peptide bond. In the absorption band of 1650 cm–1, bending vibrations of the carbonyl group occur, and in the band of 1550 cm–1, bending vibrations of the N–H bond are observed. The 3500–3000 cm–1 region is the stretching vibrations of the NH, OH and water groups. In the case of the working sample of the MFFC-2G fluoroplastic membrane, the stretching vibrations of the fluorine-substituted groups lie in the range 1100–1400 cm–1; they correspond to the C–F stretching vibrations (1198 and 1171 cm–1). The IR spectrum also shows two peaks in the region 2800–3000 cm–1; they are characteristic of biodiesels from vegetable oils. Studies of the specific output flow and the change in the pH of the permeate depending on time and transmembrane pressure were carried out. There are several periods of a decrease in the specific output flux depending on time, which is most likely due to the unblocking of the membrane pores by organic compounds in the solution being separated, and the possible formation of a boundary gel layer. The decrease in the pH of the permeate with an increase in the transmembrane pressure on the MMK-0.45 and MFFC-2G microfiltration membranes is probably due to an increase in the rate of migration of organic acids through the helium layer and the working layer of the membrane.
Reaction of CO Oxidation on the Surface of Pd Nanoparticles: Optimization by Reinforcement Learning
Authors: Lifar M. S. , Tereshchenko A. A. , Bulgakov A. N. , Guda A. A. , Guda S. A. , Soldatov A. V.
Published: April 2024

The yield of reaction products depends on the interaction between processes on the catalyst surface: adsorption, activation, reaction, desorption, and others. These processes, in turn, depend on the magnitude of the flows of reaction mixtures, temperature, and pressure. Under stationary conditions, active sites on the surface can be poisoned by reaction by-products or blocked by an excess of adsorbed reactant molecules. Dynamic control of reaction parameters takes into account changes in surface properties and adjusts temperature, flow rates and other parameters accordingly. A reinforcement learning algorithm was applied to control the oxidation reaction of carbon monoxide CO on the surface of palladium nanoparticles. The algorithm was trained to maximize the rate of carbon dioxide production based on information about the magnitude of CO, O2 and CO2 fluxes at each time step. A gradient policy algorithm with a continuous action space was chosen, and observations of the flow rates were extended over several successive time steps, which made it possible to obtain a set of non-stationary solutions. The maximum yield of the product is achieved with a periodic change in gas flows, which ensures a balance between the available adsorption sites and the concentration of activated intermediates. This methodology opens up prospects for optimizing catalytic reactions under nonstationary conditions.
Modification of the Properties of the Surface Layers of Aluminum Alloys under the Action of a High-Power Ion Beam
Authors: Panova T. V. , Kovivchak V. S.
Published: April 2024

The effect of a high-power ion beam of nanosecond duration on the stress-strain state of the surface layer of aluminum and its alloys was studied. The data of elemental and phase analysis, residual stresses, sizes of coherent scattering regions and dislocation density were compared with the microhardness value for different irradiation regimes. A decrease in the lattice parameters of the α-phase of aluminum with an increase in the ion current density was found, which indicated the deforming effect of the resulting compressive residual stresses during irradiation with a high-power ion beam. The analysis of the sizes of the coherent scattering regions in alloys compared with pure aluminum showed a tendency to their decrease; in the D16 alloy the grinding occurred by a factor of 1.5, the dislocation density increased by a factor of two, and in the V95T alloy, the dislocation density increased by a factor of three. This trend indicates a significant influence of alloying elements on the dispersion and density of dislocations with varying irradiation parameters.
Formation of Nanoclusters in Zinc-Implanted Crystalline Quartz
Authors: Privezentsev V. V. , Firsov A. A. , Kulikauskas V. S. , Zatekin V. V. , Tereshchenko A. N.
Published: April 2024

The results of the synthesis of nanoclusters of metallic zinc and its oxide in crystalline quartz implanted with 64Zn+ ions with a dose of 5 × 1016 cm–2 and energy of 40 keV and annealed in an oxygen atmosphere in the temperature range 400–900°C are presented. Scanning electron microscopy combined with energy-dispersive spectroscopy, as well as Auger electron spectroscopy and photoluminescence, were used for the study. After implantation, separate nanoclusters of metallic zinc with a size of less than 1 µm were fixed on the surface and in the near-surface layer of quartz. It was established that, during annealing, the sample underwent a transition from the phase of metallic Zn to the phases of its oxide ZnO and silicate Zn2SiO4. After annealing at 700°C, which is the most optimal for obtaining the ZnO phase, zinc oxide nanoclusters smaller than 500 nm in size were formed in the near-surface layer of quartz. A peak in the form of a doublet at a wavelength of 370 nm was observed in the photoluminescence spectrum due to exciton luminescence in zinc oxide. After annealing at 800°C, the ZnO phase degraded and the zinc silicate phase Zn2SiO4 was formed.
3He Refrigerator Based on Closed Cycle Cryocooler Cooling
Authors: Chernikov A. N.
Published: April 2024

In the Laboratory of Neutron Physics of the Joint Institute for Nuclear Research, work is underway to create gaseous neutron detectors. To prepare a working mixture of gases, it is necessary to use pure 3He, which is obtained by freezing impurities. The 3He refrigerator was created for this purpose. The refrigerator can also be used to obtain low temperatures in a physics experiment. In this work, the operating modes of the refrigerator are studied. In the continuous mode of 3He circulation, a temperature of 0.78 K was obtained. When 3He vapor is pumped out by an external pump in a single cooling mode, a temperature of 0.52 K is reached. We also study relaxation modes in which, with pre-condensed 3He, the volume of the container plays the role of a pump. A regime is presented in which the temperature of the evaporator relaxes from 1 to 1.5 K within 11 days.
Nanoscale Structure of Positive Electrodes for Lithium-Ion Batteries with Graphene-Based Additives according to Small-Angle Neutron Scattering
Authors: Yerdauletov M. , Avdeev M. V. , Tomchuk A. A. , Napolskiy F. S. , Djanseitov D. M. , Krivchenko V. A.
Published: April 2024

The adaptation of neutron scattering methods for studying the microstructure of electrode materials of lithium-ion batteries was continued in order to improve their characteristics with respect to specific energy. Using small-angle scattering of thermal neutrons, the effect of conductive carbon additives (graphene and graphene oxide) on the porous structure of electrodes made from LiFePO4, Li4Ti5O12 and LiNiMnCoO2 was studied. To separate the scattering by closed and open pores, the electrodes were wetted with a typical liquid electrolyte with a deuterated liquid carrier (dimethyl carbonate), which led to the matching of scattering by open pores. It was established that the electrically conductive carbon additives changed the electrode porosity to varying degrees and affected the wettability of materials both due to different degrees of penetration into the pores of the source material and due to the effect on the initial matrix. A universal effect on the scattering of polymer binder (polyvinylidene fluoride) was also found.
Sputtering of Metal Atoms with the Wake Potential Excited by an Electron Beam
Authors: Kalashnikov N. P.
Published: April 2024

The process of metal atoms sputtering during a corona discharge is considered. When an electron moves in a medium at some velocity, charge screening occurs with a delay in space and time, which leads to the emergence of a wake potential. The excited oscillations of the wake charge lead to the appearance of additional forces. The energy loss of a moving particle per unit path is determined by the work produced of the deceleration force that acts on the particle from the side of the wake potential it creates in the medium. The paper considers the effect of the wake potential on the ions (atoms) sputtering of the lattice matrix. A well-known expression is used for the wake potential excited by a charged particle moving with energy, greater than the Fermi energy. An expression for the sputtering cross-section of metal atoms under the action of the wake potential excited by the electron beam is obtained. It is shown that the result of sputtering does not depend on the charge sign of the incident particle (electron or ion).
Focused Ion Beams and Complementary Techniques for Study of the Silvering of Ancient Roman Coins
Authors: Sozontov E. A. , Greshnikov E. A. , Trun’kin I. N. , Pakhunov A. S. , Govor L. I. , Kurkin V. A.
Published: April 2024

Two ancient Roman silver coins dating back to the 3rd–4th century AD were studied. A set of modern micro- and non-invasive analytical techniques was used: a focused ion beam, scanning electron microscopy, energy dispersive X-ray microanalysis, micro-X-ray fluorescence analysis, neutron radiation analysis, and other methods. The research showed that Ag–Cu and Ag–Cu–Pb–Sn alloys were used, common in the prosperous years of the Roman Empire, when the Romans produced alloys with a relatively high silver content for both outer layers and the inner core of the coins. Surface silvering processes were used during different periods of crisis under the reign of Antoninii. It was established that even during the crisis, the Romans produced high quality “Antoninianus”, attempting to improve the silvering procedure using silver amalgam (Hg–Ag) – mercury was detected in the near-surface silver layer of the coins. A porous morphology of the coin surface was also revealed, which might be the result of an uncontrolled heating process and the removal of mercury through boiling.
Stability of Bilateral Discharge in the Ring Laser
Authors: Chirkin M. V. , Ustinov S. V. , Mishin V. Yu. , Serebryakov A. E.
Published: April 2024

A method has been developed for determining the threshold for the development of instability of a gas discharge in a ring helium-neon laser, taking into account the distributed capacitance “positive pole – grounded shield”. In the developed approach to stability analysis, the positive discharge of the column is replaced by an equivalent circuit, a series connection of a negative dynamic resistance ρ and balanced RL-circuits. An equivalent circuit can be synthesized by experimental studies of the linear response of a gas-discharge plasma to weak harmonic perturbations, presented in the form of frequency dependences of the complex resistance Z of a positive column. The calculation of the instability development threshold in the electrical circuit of a two-arm discharge only on the basis of the experimentally recorded frequency dependence of the complex resistance of the positive column does not allow one to extend the quantitative analysis to conditions outside the range of conditions in which the measurements were performed. To overcome this limitation, which hinders the search for the operating current, in which the development of instability is excluded for the entire temperature range of operation of ring helium-neon lasers, a model has been developed that describes the positive column of the gas discharge. The boundary of the unstable state of a two-arm gas discharge in the space of parameters is found: resistance of ballast resistors, temperature, mounting capacitance. The results obtained make it possible to maintain a two-arm DC discharge in a given range of temperature variation.
On the Spatial Resolution of a Piezoresonance Probe Sensor with a Wolfram Needle
Authors: Gorbenko O. M. , Zhukov M. V. , Lukashenko S. Yu. , Pichahchi S. V. , Sapozhnikov I. D. , Felshtyn M. L. , Golubok A. O.
Published: April 2024

In scanning probe microscopy, the various types of force interaction probe sensors are used. Silicon cantilevers with optical registration of their deflection under the influence of force interaction with the surface under study are the most widespread. Also “self-sensing” probe sensors based on a silicon cantilever or piezo tubes using piezoresistive or piezoresonance principle for measuring their deflection, respectively, are known. In this work a “self-sensing” piezoresonance probe sensor was investigated. The sensor is a piezo tube, at the free end of which a W needle with a length of several millimeters is fixed. It is generally assumed that the spatial resolution of SPM probe sensors is due to the radius of the sphere at the apex of the needle tip. However, in the oscillatory modes of scanning probe microscopy operation the “spot” of the probe’s contact with the sample can be blurred, impairing the spatial resolution. In this paper the amplitude-frequency characteristic of the piezo-tube – W needle system and the size of the effective contact spot of the probe with the sample were calculated by finite element method. The calculation results are compared with the experimental frequency response curve.
Behavior Features of the Approach Curve of a Scanning Ion-Conductance Microscope
Authors: Lukashenko S. Yu. , Gorbenko O. M. , Zhukov M. V. , Pichahchi S. V. , Sapozhnikov I. D. , Felshtyn M. L. , Golubok A. O.
Published: April 2024

The operation of a scanning ion-conductance microscope is based on the assumption that the ion current I(z) flowing in an electrolyte solution through the narrow aperture of a probe in the form of a glass nanopipette has a maximum saturation value away from the sample under study and decreases as the probe approaches the surface. The value of the scanning ion-conductance microscope operating current is usually chosen near the saturation current I ~ 09Isat. However, in some cases there is an unusual behavior of the I(z) approach curve near the surface when the ion current increases as the nanopipette approaches the sample surface. The appearance of a peak on the I(z) curve as the nanopipette approaches the sample surface is what we call the “peak effect”. It is obvious that the peak effect can lead to a failure in the operation of the scanning ion-conductance microscope servo system and noise at the images getting by scanning ion-conductance microscope. In this work the appearance of a peak on the approach curve have been studied experimentally. Considering the nanopipette near the sample surface as a microfluidic system in the form of a T – shaped channel the I(z) dependence using the finite element method and the СOMSOL software package have been calculated.
Spin-Orbit Interactions in Osmium Complexes
Authors: Asanov I. P. , Fedorenko A. D. , Vasilchenko D. B. , Grebenkina M. A. , Lavrov A. N. , Korol’kov I. V. , Kriventsov V. V. , Trubina S. V. , Asanova T. I.
Published: April 2024

Osmium compounds with the Os5d4 electron configuration and an octahedral environment of neighboring atoms attract much attention due to the influence of the spin-orbit interaction on the appearance of magnetic properties in materials. XANES spectroscopy makes it possible to obtain information about the magnitude of the spin-orbit interaction from measuring the intensity ratio of lines near the absorption edges. The influence of the spin-orbit interaction on the XANES OsL2,3 spectra in osmium compounds having an octahedral halogen environment of osmium atoms has been studied. Two types of systems have been investigated: isolated osmium clusters in complex compounds and OsCl4 compound containing polymeric chains of Os connected by bridging Cl atoms. Magnetic susceptibility measurements show a non-magnetic ground state and Van Vleck paramagnetism in the case of isolated clusters and a non-zero magnetic moment over the entire temperature range in OsCl4. As a result of measurements of the XANES spectra, high values of the line intensity ratio near the OsL3/L2 absorption edges have been obtained, which is associated with a strong influence of the spin-orbit interaction on the electronic structure. Theoretical analysis of the XANES spectra of Os compounds with different ligands and outer-sphere cations shows that the electronic structure and magnetic properties depend on the spin-orbit interaction, the crystal field splitting, the electron pairing energy, and non-cubic distortions of the Os environment.
On Influence of the Parameters of a Layered Target and Electron Beam on Diffracted Transition and Parametric X-Ray
Authors: Blazhevich S. V. , Shevchuk O. Yu. , Noskov A. V. , Fedoseev A. E.
Published: April 2024

The paper considers parametric X-ray radiation (PXR) and diffracted transition radiation (DTR) of a beam of relativistic electrons crossing a target with a periodic layered structure in the Bragg scattering geometry. The general case of asymmetric electron reflection relative to the target surface is considered, that is, when the target layers occupy a place at right angles to its surface. Within the framework of the two-wave approximation of the dynamic theory of diffraction expressions are obtained that describe the angular densities of PXR, DTR and their interference. Computational calculations of the angular densities are carried out for various values of the target parameters and a variety of quantities. The density-to-flow ratio depends on the density and on the thickness-to-thickness ratio of the periodic structure. At a large electron value, the angular dependence of the DTR on the consumed mass increases.
Modification of the Electronic Structure of Few-Layer Graphene Grown on β-SiC(001) by Neutral Red Dye
Authors: Chaika A. N. , Aristova I. M.
Published: April 2024

Graphene layers on semiconducting substrates, modified using covalent and non-covalent chemical functionalization, can be utilized for fabrication of hybrid structures combining physical properties of graphene and organic molecules. In this paper the results of investigations of the atomic and electronic structure of ultrathin graphene layers on β-SiC/Si(001) wafers modified using phenazine dye Neutral Red are presented. Continuous graphene films consisting on several atomic layers were synthesized on β-SiC/Si(001) wafers using high-temperature annealing in ultrahigh vacuum. The synthesized graphene layers were chemically modified in a solution of diazonium salt of the Neutral Red dye under white light illumination. The results of the scanning tunneling microscopy and spectroscopy experiments demonstrate the formation of a composite phenazine/graphene structure with a large energy gap in all surface regions. The molecules can be oriented preferentially parallel and perpendicular to the graphene layers and form locally ordered structures with rectangular and oblique unit cells. The electronic energy spectrum and band energy gap in different surface areas depend on the local atomic structure and the molecule’s orientation relative to the surface. According to the density functional theory calculations, local modifications of the electronic structure and band energy gap can be related to deformations (compression or extension) of the phenazine dye molecules because of their interaction with the topmost graphene layer.
Substitution in the Structure of Hydroxyapatite Doped by Iron Cations at Mechanochemical Synthesis
Authors: Isaev D. D. , Kriventsov V. V. , Petrov S. A. , Bystrov V. S. , Bulina N. V.
Published: April 2024

Hydroxyapatite, a mineral of the apatite group, has an important and useful property – the propensity for various kinds of substitutions, which allows to modify its properties and expand the possibilities of using the synthetic material. The properties of the synthesised substance depend on the way it is produced, as the synthesis conditions influence the structural and morphological characteristics of the particles being formed. This paper shows that at mechanochemical synthesis with the introduction of iron cations as a dopant the structure of hydroxyapatite, in which the dopant occupies the position of the calcium cation, is formed. This type of substitution is accompanied by a decrease in the lattice parameters of the hydroxyapatite. It is shown that iron cations have predominantly a 3+ charge, which is independent of the charge of the initial reagent containing the iron cation. It was also found that in the process of mechanochemical synthesis under certain conditions, simultaneous partial replasement of calcium cations with iron cations and phosphate group with carbonate group can be realized. The powders obtained by mechanochemical synthesis were characterized by powder diffraction, infrared spectroscopy, near-edge X-ray absorption fine structure spectroscopy and Mössbauer spectroscopy.
Study of the Physical and Mechanical Properties of Coatings Obtained by Vacuum-Arc Spraying of Ti–B–Si–Ni Cathodes Manufactured Using Self-Propagent High-Temperature Synthesis and Pressing
Authors: Savostikov V. M. , Leonov A. A. , Denisov V. V. , Denisova Yu. A. , Skosyrsky A. B. , Shulepov I. A.
Published: April 2024

The article presents the results of a study of vacuum-arc coatings obtained by sputtering Ti–B–Si–Ni cathodes, manufactured by the method of self-propagating high-temperature synthesis with simultaneous pressing. The techniques for manufacturing cathodes of the indicated composition were characterized; the modernized NNV 6.6-I1 device, the conditions and modes of coating deposition in an argon atmosphere and in a nitrogen + argon gas mixture in a ratio of 90/10 were described. To study the physical and mechanical properties of the resulting coatings, the hardness was measured at different loads on the indenter; the strength of adhesion to the base was assessed by the Rockwell method; the elemental composition of the cathodes and the (Ti–B–Si–Ni)N coating was determined by Auger spectroscopy and the phase composition of the (Ti–B–Si–Ni)N coating was determined by X-ray phase analysis; a study of the properties of the coating (Ti–B–Si–Ni) was carried out by the scratching method (scratch testing). As a result of a comprehensive analysis of the results obtained, it was concluded that the high hardness of the (Ti–B–Si–Ni)N coating (more than 40 GPa) is due to its composition, which includes both nitrides and highly hard titanium borides. The heterophasic nature of the structure of this coating can serve as a contribution to the stressed state of the material. The coating has a gradient-layered structure. The material contains a Ti–B–Si–Ni layer bonding with the substrate and the main functional layer (Ti–B–Si–Ni) N. The coating has both high hardness and sufficient adhesion to the substrate (adhesion) determined by the scratch testing. The combination of these properties makes the material promising for its practical application in the production of tools.
Sizing the EUV Laser-Plasma Source for a Microscope
Authors: Reunov D. G. , Malyshev I. V. , Perekalov A. A. , Nechay A. N. , Chkhalo N. I.
Published: April 2024

The size and intensity of laser-plasma sources based on pulsed argon gas jets operating at a wavelength of 13.84 nm were studied. The gas jet was excited by laser radiation at a wavelength of 1064 nm with a pulse duration of 4.4 ns, a repetition frequency of 10 Hz, and a pulse energy of 0.5 J. Two methods of forming a jet of a pulsed gas target were studied: using a jet with a supersonic nozzle and using a capillary. The capillary source is commercially available. The sources were certified using a mirror microscope operating in the extreme ultraviolet region at a wavelength of 13.84 nm. It was found that due to the possibility of supplying a higher pressure of the working gas to the nozzle inlet, increasing the density and reducing the exit angle of the gas jet in the supersonic nozzle compared to the capillary, the peak radiation intensity at a wavelength of 13.84 nm increased six times. The full width at half maximum of the nozzle-based source diameter was 250 ± 10 μm with a profile close to Gaussian. In the field of view of a microscope of 25 × 25 μm, the nonuniformity of illumination from the “source on the nozzle” is about 1%; in the field of view of 50 × 50 μm, it is about 4%. The full width at half maximum of the source diameter based on a commercial valve with a capillary source was 330 ± 10 µm with a profile close to П-shaped. Based on the results of the comparison, an upgraded version of the microscope with up to 350× magnification will use a nozzle-based source.
Design of the Prototype of the Radio Frequency Quadrupole Sections for the Compact Neutron Source DARIA
Authors: Semennikov A. I. , Sitnikov A. L. , Kropachev G. N. , Kulevoy T. V. , Naumenko M. Yu. , Anfalova O. V. , Kraev V. S.
Published: April 2024

The DARIA compact neutron source project based on a linear resonant proton accelerator is aimed at creating a serial facility capable of providing the Russian scientific community with pulsed neutron beams with intensities comparable to those of research nuclear reactors. The absence of fissile material makes it possible to significantly reduce the radiation safety requirements for such installations and, consequently, to place them at the site of leading scientific centers and universities that train specialists in the field of neutron physics. Under a grant from the Ministry of Science and Higher Education, key elements of the facility are being developed. The design and sequence of manufacturing for a full-scale model of an accelerator section with radio frequency quadrupole focusing and a resonator with drift tube linac are presented.
Rotating Water-Cooled Beryllium Target for a Compact Neutron Source
Authors: Shvets P. V. , Prokopovich P. A. , Fatyanov E. I. , Clementyev E. S. , Moroz A. R. , Kovalenko N. A. , Goihman A. Yu.
Published: April 2024

With the declining number of neutron sources in the world and the decommissioning of research reactors, projects to develop compact neutron sources are attracting more and more attention. The DARIA project suggests the use of a proton beam accelerated to an energy of 13 MeV, which, hitting a beryllium target, creates a neutron beam through the a nuclear reaction (p, n). The reaction yield is three neutrons per 1000 protons, so in this process most of the proton beam energy is released as heat in the target. Intense heating of a beryllium target in the absence of sufficient heat removal can lead to its destruction. A system has been developed for efficient heat removal from a beryllium target during its irradiation with a proton beam. It is a rotating water-cooled beryllium target and is capable of removing a large thermal power from the inner (water-side) surface of the target. For the proposed system, numerical simulations of the speed and pressure of the coolant were carried out. The limiting pressure leading to the destruction of the target and the flows corresponding to this limiting pressure were calculated. Thermodynamical simulations allowed us to evaluate both the average temperature of the system and the peak local (caused by short high-energy pulses) temperatures.
A Two-Mode Time-of-Flight Neutron Reflectometer for a Compact Neutron Source DARIA
Authors: Syromyatnikov V. G. , Grigoryeva N. A. , Grigoriev S. V.
Published: April 2024

The concept of a two-mode neutron reflectometer with a polarizer, two spin-flippers and an analyzer of polarization after passing through the sample is presented. A reflectometer designed for a compact neutron source DARIA is planned to measure the spectrum of a reflected “white” neutron beam using the time-of-flight method at a fixed glancing angle with the possibility of using both polarized and non-polarized neutrons. The main geometric and physical parameters of the neutron reflectometer are presented. With a neutron pulse duration τ = 100 µs and a total length of the time-of-flight base L = 8 m, the pulse repetition rate can reach f = 165 Hz for the wavelength range Δλ = 3 Å and resolution Δλ ≅ 0.05 Å. The use of polarization analysis elements of a reflectometer at a beam polarization exceeding 96% and an efficiency of spin flippers close to unity makes it possible to study magnetic thin-film nanostructures in detail.
Measurements of the Characteristics of Fine Grain Graphite Used as a First Wall Material for the T-15MD TOKAMAK
Authors: Begrambekov L. B. , Puntakov N. A. , Ayrapetov A. A. , Grunin A. V. , Dovganyuk S. S. , Zakharov A. M. , Savvin N. O. , Grashin S. A. , Arkhipov I. I.
Published: April 2024

In this work, properties of fine grain graphite that will be used as a plasma-facing material in the T-15MD Tokamak are measured and studied. Density and porosity, thermal diffusivity and thermal conductivity, as well as the crystal grain size and impurity content of graphite are measured. The measurement results were compared to the corresponding parameters of MPG-6, MPG-7 and MPG-8 graphites. Characteristics of hydrogen and methane retention in graphite and conditions of their desorption depending on temperature of preliminary annealing, its duration, exposition of fully annealed samples in atmospheric gas at normal conditions. Influence of irradiation of the samples by deuterium ions with different energies on the characteristics of hydrogen trapping and desorption. In all cases, attention was paid to the possibility of influence of experimental conditions on trapping and desorption of hydrogen left in graphite after its production, as well as the one trapped from the atmosphere. Based on the data obtained and the expected conditions in the T-15MD’s plasma chamber, optimal modes for annealing of graphite received from producer and temperatures of the tokamak’s plasma-facing elements that assist in removal of hydrogen from graphite are determined.
Estimation of the Barocryodeformation Effect on the Microstructure and Mechanical Properties of Copper
Authors: Danyuk A. V. , Merson D. L. , Chernyaeva E. V.
Published: April 2024

The microstructure, mechanical and acoustic properties of copper samples in the initial state and after barocryodeformation in different modes have been studied. It is shown that cryogenic temperatures contribute to significant grain refinement due to the activation of mechanical twinning processes; a homogeneous structure with an average grain size of 5–8 µm is formed. Barocryodeformation at temperatures up to 125 K leads to a decrease in plasticity and a significant increase in hardness. A further decrease in temperature, on the contrary, contributes to a significant increase in plasticity, as well as a decrease in hardness. A correlation has been noted between the median frequency of acoustic emission and the hardness value at all barocryodeformation temperatures.