bluuebunny/crossref_metadata_2025 huggingface dataset:
Geopolitics’ past and future: negation of the negation
Authors: Neimark Mark Afroimovich
Published: April 2024

In a radically changed world, geopolitical costs and errors as a result of underestimation or, conversely, overestimation of increasingly non-linear hybrid processes, conflicting trends and often spontaneous events acquire increased practical and political significance. Under these conditions, the focus of research attention could not but be on the recently published work of French researchers and international experts under the catchy and meaningful title “The world will never be the same”. In the focus of the analysis is the updated context of modern crisis geopolitics. The conceptual and analytical basis of the text is formed by extensive introductory and at the same time generalizing sections that systematize two dozen chapters on a variety of international topics and problems. They were written by the co-leaders of the team of authors, well-known French international political researchers Bertrand Bady and Dominique Vidal. A new approach is put at the forefront, which is not predetermined in advance, but is created on the basis of life practice as a result and under the influence of historical surprises, unforeseen and even previously unimaginable events. An attempt was made to consider the problems of the future world order through the prism of great-power contradictions, the confrontation of various value orientations and development models with an emphasis on the competition of democracies and autocracies. On the example of the United States, the concept of world domination is rethought. The book reflects new features of the expert-analytical work of French international researchers. The authors are aware that the confrontational severity of the crisis situation in Ukraine and its internationalization in a variety of hybridized forms have sharply “shaken” the more or less established balance of power not only in the European region, but throughout the global space. In general, they agree that optimistic options for a new world order are at stake. In separate sections of the book, the chaos of world politics and international relations is linked to the overstrain of the US hyperpower, which is approaching a critical point.
Migration policy in Albania: institutional aspects
Authors: Gorokhov Stanislav Anatol'evich , Dmitriev Ruslan Vasil'evich
Published: April 2024

After the fall of the communist regime Albania turned from a closed country into a country of net emigration. The article examines the evolution of Albanian migration policy from 1990 to 2022. The purpose of the study is to identify the approaches to the regulation of international migration in the context of the integration of Albania into the EU. The research is based on the state and supranational sources in the field of migration: legislative and regulatory acts, strategies, action plans, international agreements. The period under consideration is divided into two almost equal parts in relation to the level of participation of Albania in the regulation of migration. The first period (until the mid-2000s) is characterized by a relatively passive stance, relying primarily on external forces which regulate migration from Albania, such as other countries of the region and the EU. With the adoption of the Strategy for Migration Management in 2005 Albania took a more active stance, focused, on the one hand, on comprehensive and multidirectional interaction with the Albanian diaspora and, on the other, on reducing emigration by creating new jobs. It is revealed that the measures taken to return the representatives of the diaspora to the country and reduce the emigration activity of the current inhabitants of Albania are not enough. The diaspora plays a significant role in the economy of Albania, however, it does not seek re-emigration. The effect of job creation was largely offset by the European migrant crisis.
Crisis of values’ convergence in relations between Central Europe and Brussels
Authors: Shishelina Lyubov Nikolaevna
Published: April 2024

The article analyses the origins of the current differences between Brussels and the countries of Central Europe, which tend to deepen and require much effort in order to preserve the unity of the European Union. The contradictions were already evident at the time of the admission of the countries to the EU, that took place according to an accelerated scenario in conditional compliance of these countries with the Maastricht and Copenhagen criteria. The condition, which dealt directly with the issues of market expansion and adaptation of new countries to it, initially received more attention than the condition, which involved political and legal issues. The deepening of the political union of the EU took place already after the admission of new countries, for many of which the new depths of convergence turned out to be unacceptable. However, that meant provoking confrontation with Brussels. Over 20 years of coexistence, the EU members made necessary compromises, however, from the middle of the second decade of the 21st century, disagreements became substantial and Brussels, using the financial leverage of the EU, began to pressure defiant countries, primarily Hungary and Poland. The author comes to the conclusion that in the current difficult international situation, the sides will have to reach a certain compromise.
Denmark: portfolio allocation in the government and parliament in the sphere of foreign policy
Authors: Grigoreva Oxana Vladimirovna , Plyusnin Nikita Olegovich
Published: April 2024

The growing number of coalition governments in European states, many of which are minority governments, raises questions about how they form and function. The case of Denmark, where such governments have long become a part of political everyday life, helps to identify the main specific features of foreign policy portfolio allocation in the cabinet and the Danish parliament, since the Kingdom is one of the most successful examples of cooperation between the government and parliament in the field of foreign policy and defence. The article analyses the mechanisms and factors for the foreign policy portfolio allocation in 2001-2023, taking into account successive "blue" and "red" party blocs. Various theories of coalition formation and portfolio allocation in coalition governments are used to explain the distinguishing features of such allocation at a particular historical stage. In addition, general features of the development of the Danish political system at the present stage, the main trends and prospects for this development are considered. The authors conclude that when allocating portfolios in the government, preference is given to "junior" coalition partners, while in parliament - to "senior" ones; the opinion of the Danish People's Party is taken into account by coalition partners without the Party’s inclusion in the government; the choice is given in favour of popular and authoritative politicians constituting the foreign policy elite of Denmark over the past three decades; the functioning of the Foreign Policy Committee provides some kind of balance of power in the Danish Parliament on foreign and defence policy. It is also found out that the strategies for coalition formation and foreign policy portfolio allocation do not significantly differ between the "blue" and "red" party blocs, but follow the same logic aimed at maintaining the stability of the minority government’s position.
International labor migration policy of the European Union
Authors: Revenko Nikolai Sergeevich
Published: April 2024

The cross-border movement of labour is associated with an objective need for the host country to accept and comply with the relevant rules. This problem has always existed for the European Union and its member states due to the attractiveness of the region for migrant workers, relatively high standard of living and the widely diversified sectoral structure of the economy. Based on the analysis of the relevant directives, the article chronologises the stages of regulation of international labour migration in the EU with an emphasis on the present. Close attention is given to the EU regulatory practice of the issues of attracting highly qualified and seasonal labour third-countries workers, students and researchers, facilitating intra-corporate transfers. In this context the regulatory vector in the area of international labour migration to the EU is aimed at obtaining benefits from the influx of the necessary labour force through the creation of favorable conditions for its integration into European society. The implementation of Directive on the conditions of entry and residence of third-country nationals for the purpose of highly qualified employment will depend on the applicable practices of the EU member states. The study reveals the dualism of the economic effects of international labor migration received by the EU at present: positive in the form of a relative reduction in unit costs due to labor components, the flow of technological knowledge and negative ones associated with the displacement of part of local labor resources, the outflow of funds from foreign workers, changes in the structure of aggregate demand, the impact on the level of wages, aggravation of interethnic and interfaith conflicts against the background of a low level of integration of foreigners into local society.
Freezing of russia's arctic chairmanship
Authors: Zhuravel Valery Petrovich
Published: April 2024

The author overviews the main results of Russia's chairmanship of the Arctic Council (AC, Council) in 2021-2023, analyses its relationship with domestic and international governance. Four main periods of the Russian chairmanship are defined. It is noted that due to the Ukrainian conflict, the Russian chairmanship was boycotted by Western countries. In the conditions of geopolitical instability, the Russian Federation managed to organise most of the planned events. During this period Russia concentrated on the infrastructure of the Northern Sea Route, the socio-economic development of the Arctic regions of the Russian Federation. However, due to the position of the Western countries, it was not possible for Russia to fully achieve and implement the scheduled activities. It negatively affected the work of the Organising Committee, representative ministries, departments, Arctic regions and scientific organisations. The course of the chairmanship was disorganized. May 2023 Russia remotely handed over the chairmanship of the Arctic Council to Norway, hoping to restore the former status. The Russian Federation believes that the problems of the Arctic region can be solved only through balanced and mutually beneficial international cooperation.
China's investment in EU member-states’ seaports
Authors: Yanbin U
Published: April 2024

The article focuses on the Chinese port investment in the EU countries and analyses the motivation and current situation behind it from the Chinese perspective as well as explains the European perception of investment and its future prospect. The study is based on the Chinese and European official documents and Chinese scholars' articles. In recent years, the number of Chinese port investment projects in European countries has been increasing, and the role of ports as hubs in China-EU economic and trade cooperation has become more prominent. However, the negative perception of Chinese port investment in the EU also gradually increases. The EU is concerned that Chinese port investments will challenge the market dominance of European companies in the port shipping sector and cause political division within the EU, even with far-reaching geopolitical implications and security problems. Chinese academics generally believe that China's investment in EU ports is purely a matter of its own economic and trade interests rather than security considerations, and advocate that China and EU should actively promote port cooperation, follow the path of spatial integration and integration of interests, and build a multi-party community of interests for China-EU port cooperation, and require Europe to abandon the direct influence of external factors and commit to fostering a positive interaction between China and EU. It is necessary for Europe to work towards an effective cooperation between China and the EU on economic development issues and political security issues instead of creating a malicious confrontation.
The Formation and Stationary Maintenance of Peaked Pressure Profiles in Turbulent Tokamak Plasmas
Authors: Pastukhov V. P. , Smirnov D. V. , Chudin N. V.
Published: April 2024

The theoretical model for increasing peaking of radial distribution of plasma thermal energy and plasma energy confinement time improvement due to the formation of current profiles those provide the increased value of the safety factor qb at the outer plasma boundary is considered. The model for the formation and stationary maintenance of the peaked current density profiles those ensure the maintenance of plasma column equilibrium state with increased qb value and conservation of q0=1 at the magnetic axis is developed. The model is based on the significant ramp down of the Iind current maintained by the inductor with simultaneous central ECR heating and electron cyclotron current drive (ECCD) switching on. It is shown by the computer simulations of the self-consistent time evolution of turbulent plasma for the conditions of T-10 and T-15MD tokamaks that in the shot scenarios with three- or four-fold decrease in the Iind current at the ECRH stage of shots it was achieved an approximately two-fold enhancement of the electron and ion temperatures at the axis of the plasma column as compared to the standard shots with the same heating powers.
Efficiency of Conversion of the Magnetic Energy into Z-Pinch Radiation of Nested Arrays of Mixed Composition at the Angara-5-1 Facility
Authors: Mitrofanov K. N. , Gritsuk A. N. , Aleksandrov V. V. , Branitsky A. V. , Grabovsky E. V. , Oleinik G. M. , Frolov I. N.
Published: April 2024

The results of experiments on the study of the generation of high-power pulsed soft X-ray (SXR) emission with a photon energy higher than 100 eV (in the spectral range with wavelengths λ shorter than 120 Å) during the plasma implosion of nested arrays of mixed composition with different ratios of array radii carried out on a pulse power facility Angara-5-1 with a discharge current level of up to 3.5 MA are presented. The outer array consisted of fibers of a substance with a low atomic number (plastic), and the inner array consisted of a substance with a high atomic number (tungsten, W). In the case of nested arrays of this design, a significant increase in the peak SXR power was obtained compared to single tungsten arrays with the same parameters as for the tungsten array in the inner array. By optimizing the linear mass of the outer array and the ratio of array radii, powerful SXR pulses were prepared with a high pulse power up to 18 TW, pulse energy of ~140 kJ and short pulse duration of ~5 ns. It is shown that by optimizing the linear mass of the outer array (fiber array) it is possible to achieve ~90% conversion of the electromagnetic energy pumped into the vicinity of the array into X-ray emission pinch energy. In this case, the fraction of the kinetic energy of the plasma implosion into the emission energy is not higher than 30%. In shots optimal over the output SXR power, an increase in the fraction of the X-ray emission energy in the spectral range of λ ∈ (30, 40) Å was recorded that is 30–100% than that in single tungsten arrays with similar parameters.
Distinctive Features of Anomalous Plasma Radiation in Experiments on Electron Cyclotron Heating Using Extraordinary Wave at the Second Resonance Harmonic in a Wide Density Range
Authors: Gusakov E. Z. , Popov A. Yu.
Published: April 2024

A detailed interpretation of the effect of anomalous radiation is given, which was first observed at the TEXTOR tokamak in experiments on electron cyclotron resonance heating by the extraordinary wave at the second resonance harmonic in a wide range of plasma densities.
Physical Properties of a Low-Power Helicon Source Operating on a High-Frequency Discharge with a Capacitive Component
Authors: Zadiriev I. I. , Vavilin K. V. , Kral’kina E. A. , Nikonov A. M. , Shvydkii G. V.
Published: April 2024

The results of an experimental study of a low-power RF plasma source placed in a longitudinal magnetic field (helicon thruster), when it operates on a capacitive RF discharge and inductive RF discharges with a capacitive component, are presented. A significant dependence of the characteristics of the ion and electron fluxes of the source on the induction of a constant magnetic field is shown. The fundamental applicability of capacitive RF discharge as a working process in the studied plasma source is demonstrated. It is shown that the increase in the average energy of ions in the flow at the outlet of the source with the appearance of the capacitive component of the discharge is slight.
Interaction of Relativistic Electrons with Packets of the Electromagnetic Ion Cyclotron Waves of Finite Length and Low Amplitude
Authors: Grach V. S. , Demekhov A. G.
Published: April 2024

Interaction of relativistic electrons with packets of the electromagnetic ion cyclotron waves of finite length and low amplitude in the Earth’s radiation belts is analyzed. The variance of the equatorial pitch angle of electrons for wave packets located near the Earth’s geomagnetic equator is estimated analytically within the linear approximation. The analytical estimates agree with the results of numerical test-particle simulation. It is demonstrated that reduction in the packet length extends the interaction range to lower energies beyond the range of resonant energies. Such an interaction can result in precipitation of electrons with energies on the order of several hundred kiloelectronvolts into the ionosphere.
On the Possibility of Achieving Thermonuclear Ignition During Magnetic Compression of High-Temperature Magnetized Plasma by the Current of a Disk Explosive Magnetic Generator
Authors: Ivanovskii A. V. , Mamyshev V. I.
Published: April 2024

One of the directions for achieving thermonuclear ignition is compression of a heated, magnetized plasma by a liner. This concept was developed in the USA at the Z Machine (MagLIF project). To achieve ignition, it is necessary to create a current pulse with an amplitude of 60 MA or higher. The Z Machine produces currents with amplitudes up to 25 MA. The development of more powerful installations is a problem for the future. At the same time, today already, the explosive magnetic generators create the required currents with long current rise times. In this work, based on calculation results of the compression of a hot magnetized plasma, the possibilities of achieving ignition using modern disc explosive magnetic generators are discussed.
Structure of Fluctuations in the Edge Plasma of a Stellarator in Modes with Transport Transitions
Authors: Vasil’kov D. G. , Skvortsova N. N. , Kharchev N. K.
Published: April 2024

The evolution of fluctuating signals from electrostatic and magnetic probes and reflectometry on the L-2M stellarator is presented. The L-2M facility is a quasi-stationary toroidal magnetic trap in which plasma is generated and heated by high-power pulsed microwave radiation. Pulses with transitions to improved confinement modes accompanied by an increase in energy, increase in plasma density, and restructuring of the peripheral electric field, were analyzed. Spectral analysis of signals is carried out using Fourier analysis and various wavelets. The possible influence of magnetohydrodynamic and kinetic instabilities on the development of transient processes is considered.
Determination of Layer-By-Layer Profiles of Hydrogen Isotopes in Carbon and Beryllium Based on Electron Spectroscopy Methods
Authors: Afanas’ev V. P. , Lobanova L. G.
Published: April 2024

A quantitative method for interpreting the spectroscopy signal of elastically reflected electron peaks is constructed taking into account the layer-by-layer analysis of the content of hydrogen isotopes in structural materials used in the international experimental thermonuclear reactor ITER under construction. The relative protium and deuterium concentrations in hydrocarbon samples are determined. The relative deuterium concentrations in a beryllium sample are determined.
Relevance of the Wigner–Seitz Cell Approximation for the Coulomb Clusters
Authors: Shpil’ko E. S. , Zhukhovitskii D. I.
Published: April 2024

A molecular dynamics simulation of a system of massive charged particles on a compensating homogeneous background confined by a spherical surface has been carried out. A crystallized cluster is a set of nested spherical shells of almost the same structure and a core. It is shown that cluster melting is a combination of shell and core melting. It is found that the values of the Coulomb coupling parameter Γ corresponding to these two types of melting do not depend on the cluster size. Methods for determining Γ based on the Wigner–Seitz cell model are discussed. It is shown that the estimate based on the root-mean-square deviation of a particle from the center of its cell is unreliable due to the self-diffusion of particles. A relation is proposed that defines Γ in terms of the root-mean-square velocity and acceleration of the particle and does not include the root-mean-square deviation of the particle from its average position. It is shown that this relation is satisfied with high accuracy not only for the crystallized, but also for the liquid state. Thus, it has been demonstrated that the Wigner–Seitz cell model is applicable to the strongly inhomogeneous system under consideration.
Synthetic Diagnostic of Spectra of Charge-Exchange Atoms
for Analysis of Influence of the MHD Instability on Fast-Particle
Confinement in Spherical Tokamaks Globus-M/M2
Authors: Kiselev E. O. , Balachenkov I. M. , Bakharev N. N. , Varfolomeev V. I. , Voronin A. V. , Goryainov V. Yu. , Gusev V. K. , Zhiltsov N. S. , Zenkova O. A. , Kurskiev G. S. , Melnik A. D. , Minaev V. B. , Miroshnikov I. V. , Patrov M. I. , Petrov Yu. V. , Sakharov N. V. , Skrekel O. M. , Telnova A. Yu. , Tkachenko E. E. , Tokarev V. A. , Tyukhmeneva E. A. , Khromov N. A. , Chernyshov F. V. , Shchegolev P. B.
Published: April 2024

Absorbed power of the neutral-injection beam in spherical tokamaks Globus-M/M2 is estimatednumerically. Deceleration of fast particles is simulated by means of the NUBEAM code. The signal of analyzerof charge-exchange atoms is simulated by means of the FIDASIM code using the distribution functionof fast ions calculated by means of the NUBEAM code. Comparison of calculated and experimental signalsallowed determining the degree of influence of instabilities on confinement of fast particles along withabsorbed beam power.
Development of Next-Generation Spherical Tokamak Concept.
The Globus-3 Tokamak
Authors: Minaev V. B. , Mineev A. B. , Sakharov N. V. , Petrov Yu. V. , Bakharev N. N. , Bondarchuk E. N. , Bondar A. V. , Varfolomeev V. I. , Voronova A. A. , Gusev V. K. , D’yachenko V. V. , Kavin A. A. , Kedrov I. V. , Konin A. Yu. , Kudryavtseva A. M. , Kurskiev G. S. , Labusov A. N. , Miroshnikov I. V. , Rodin I. Yu. , Tanchuk V. N. , Trofimov V. A. , Filatov O. G. , Shchegolev P. B.
Published: April 2024

The concept of next-generation spherical tokamak is being considered: the Globus-3 project,which, in its characteristics, is compatible with the infrastructure existing at the Ioffe Institute, but differsfrom the currently operating Globus-M2 tokamak in the stronger toroidal magnetic field (1.5–3.0 T) andincreased duration of plasma discharge. The parametric analysis data are presented that determined the preliminaryselection of the facility parameters. Three options for the electromagnetic system were considered:with the warm copper coils, with the pre-cooled copper coils and with the coils made of high-temperaturesuperconductors. For the first option, the concept for designing the electromagnetic system and vacuum vesselof the facility has been developed. The basic shot scenario with duration of up to 3 s at the field of 1.5 Tand plasma current of 0.8 MA is presented.
Heat Load onto the Globus-M2 Tokamak Wall
due to Fast Ion Loss during Development
of Toroidal Alfvén Eigenmodes
Authors: Bakharev N. N. , Balachenkov I. M. , Varfolomeev V. I. , Gusev V. K. , Kiselev E. O. , Kurskiev G. S. , Melnik A. D. , Minaev V. B. , Miroshnikov I. V. , Petrov Yu. V. , Sakharov N. V. , Skrekel O. M. , Telnova A. Yu. , Tokarev V. A. , Tukhmeneva E. A. , Chernyshev F. V. , Shchegolev P. B. , Yashin A. Yu.
Published: April 2024

The results of experiments are described, which were performed at the Globus-M2 tokamak andaimed at studying the fast ion loss at the outer tokamak wall due to fast ions interaction with the toroidalAlfvén eigenmodes. The local heating of carbon tiles was experimentally measured, and the correspondingheat flux was calculated. It was shown how simulations of the lost particle orbits can explain the characteristicfeatures of the spatial map of wall heating. The flux of lost fast particles onto the wall was studied as a functionof the instability amplitude. It has been demonstrated that the simulations predict similar dependence of thefast ion flux on the instability amplitude and also correlate its nature to the peculiarities of fast ions spatialdistribution.
Formation of a Spray of Conducting Liquid under High Voltage and Electrical Discharge Plasma
Authors: Saveliev A. S.
Published: April 2024

The joint impact of an electrical discharge and a gas–droplet flow of a conducting liquid created by a centrifugal nozzle is studied. In the experiment, the electrical parameters of the discharge are recorded, and the local characteristics of the spray, namely, the droplet diameter distributions of the number of droplets and the components of their velocity vector are measured. The measurements are carried out using double shadow microphotography. The effect of a spray of a conducting liquid on the time-averaged electrical parameters of the discharge, as well as changes in the properties of the spray under the influence of high voltage and current, are studied. Additionally, the spray characteristics are measured when a high voltage of pre-breakdown value is applied. High-speed photography of a discharge in the presence of droplets of conducting liquid is carried out.
Control of Plasma Potential in GOL-NB Axisymmetric Multiple-Mirror Trap
Authors: Ivanov I. A. , Polozova P. A. , Batkin V. I. , Kuklin K. N. , Kurkuchekov V. V. , Melnikov N. A. , Polosatkin S. V. , Postupaev V. V. , Rovenskikh A. F. , Sidorov E. N. , Skovorodin D. I.
Published: April 2024

The results on applying the technique of vortex plasma confinement in the GOL-NB facility are presented. The first experiments on optimizing the biasing the in-chamber electrodes demonstrated an improvement in the dynamics of trapping the injected fast hydrogen atoms, as well as a decrease in the fluctuations of local plasma parameters in the central trap and an increase in the plasma decay time. The geometry of in-chamber electrodes arrangement, as well as the polarity and magnitude of the supplied potentials, correspond to the theory of vortex confinement and to those in similar studies at other open traps.
On the Question of the Formation of the Lightning Current
Authors: Aleksandrov N. L. , Ponomarev A. A. , Syssoev A. A. , Iudin D. I.
Published: April 2024

The bipolar lightning development model was used to study the dependence of the potential that is transported to the earth by the downward leader channel. It was shown that this parameter strongly depends on the starting position of the lightning and on the trajectories of formation of its bipolar leaders. It was shown that the main reason for the change in potential is not the loss of voltage in the lightning channel with a finite conductivity but its polarization in the electric field of the storm cloud. An estimate was made of the range of potential variation in the channel with ideal conductivity depending on the starting position and trajectory of the lightning at a constant charge in the thunderstorm cell. It was shown that, for the variation of the lighting current within two orders of magnitude, a mere twofold change in the charge of the thunderstorm cell is sufficient. The preferable starting position is found for the lightning whose upward leader can penetrate into the upper layers of the troposphere, turning into a blue jet.
Proton Conductivity in Rare-Earth Fluorine-Containing Molybdates NaLn4Mo3O15F
Authors: Baldin E. D. , Sorokin T. A. , Orlova E. I. , Gorshkov N. V. , Kharitonova E. P. , Lyskov N. V. , Goffman V. G. , Voronkova V. I.
Published: April 2024

The fluorine-containing fluorite-like compounds of composition NaLn4Mo3O15F (Ln = La, Pr, Nd) are produced using the method of solid-phase synthesis in air. Their thermomechanical and conducting properties, as well as hygroscopicity, are studied. It is confirmed that the synthesized specimens are isostructural to the cubic compounds Ln5Mo3O16 with the fluorite-like structure. It is shown that in the temperature range of 20–600°C, the specimens of NaLn4Mo3O15F (Ln = La, Pr, Nd) expand linearly, and their thermal expansion coefficients (13–14) × 10–6 K–1 are close to the coefficients of conventional SOFC electrolytes, for example, YSZ. Using the thermal gravimetric analysis, it is shown that the weight loss of the studied specimens in the range from 30 to 700°C is caused by their hygroscopicity. The electrophysical properties of the compounds are studied using the method of impedance spectroscopy in the humid atmosphere, and the proton component of conductivity is revealed.
Structure, Oxygen Mobility, and Electrochemical Characteristics of La1.7Ca0.3Ni1 ‒ xCuxO4 + δ Materials
Authors: Sadykov V. A. , Sadovskaya E. M. , Eremeev N. F. , Maksimchuk T. Yu. , Pikalov S. M. , Filonova E. A. , Pikalova N. S. , Gilev A. R. , Pikalova E. Yu.
Published: April 2024

The Ruddlesden‒Popper phases pertain to numerous promising materials with the mixed ionic-electronic conductivity used in devices such as oxygen-conducting membranes, solid oxide fuel cells (SOFC), and electrolyzers, which operate in the intermediate temperature region. Their high total conductivity and oxygen mobility make these materials candidates for the mentioned applications. The structure, the oxygen mobility, and the electrochemical characteristics of the promising materials La1.7Ca0.3Ni1 – xCuxO4 + δ (x = 0–0.4) are studied. According to the high-precision XRD data, all synthesized materials are single-phased and have the tetragonal structure. The unit cell parameter c and the cell volume increase upon doping with copper. The content of overstoichiometric interstitial oxygen decreases with doping and the compositions with the high copper content become oxygen deficient. The samples are characterized by the nonuniform oxygen mobility. By and large, the trend for the decrease in the oxygen mobility with the increase in the Cu content is observed in the series of La1.7Ca0.3Ni1 – xCuxO4 + δ samples. By impedance spectroscopy studies, it is shown that the electrodes with the La1.7Ca0.3Ni1 – xCuxO4 + δ functional layers with the copper content x 0.2 have a higher electrochemical activity. The factors responsible for the efficiency of electrodes are analyzed. The results obtained in this study demonstrate that La1.7Ca0.3Ni0.6Cu0.4O4 + δ materials are the candidates for the air electrodes in electrochemical devices.
The Electrophoretic Deposition of Lithium Cobaltate Nanosized Particles on the Surface of Metals and Electroconductive Oxide Ceramics
Authors: Khokhlov V. A. , Modenov D. V. , Dokutovich V. N. , Vovkotrub E. G. , Kochedykov V. A. , Akashev L. A. , Malkov V. B. , Pankratov A. A. , Fetisov A. V.
Published: April 2024

The deposition of LiCoO2 nanosized particles synthesized in LiCl–CoCl2 melts on the surface of nickel foil, copper, chrome–cobalt alloy, and platinum mesh in aqueous solutions of lithium chloride at the room temperature as well as on the surface of the electron-conducting La0.6Sr0.4MnO3 oxide ceramics in chloride melt at temperature of ca. 700°C is studied. The methods of vibrational spectroscopy, X-ray photoelectron spectroscopy, ellipsometry, and scanning electron microscopy have revealed the features of the chemical composition, structure, and morphology of the precipitates obtained.
Effect of Ga3+ and In3+ Ions on the Anodic Dissolution of Aluminum in KOH Ethanol Solutions
Authors: Rybalka K. V. , Beketaeva L. A.
Published: April 2024

The anodic dissolution of aluminum in the KOH ethanol solutions is considered. It is shown that an addition of gallium and indium compounds to the 2 M KOH solution in 96% ethanol leads to an abrupt increase in the anodic dissolution current of aluminum near the open-circuit potential and its shift by 300 mV toward negative values. The discharge galvanostatic curves in the solutions with the additives of gallium and indium compounds contain a flat discharge plateau at the current densities up to 4 mA/cm2. The hydrogen evolution rate in a number of KOH ethanol solutions is measured.
Analysis of Experimental Results of Defect Concentraions in the Surface Layer of Acceptor Doped Ceria
Authors: Riess I.
Published: April 2024

Recent experimental results of the dependence on oxygen partial pressure, P(O2), of the small polarons concentration in the monomolecular surface layer of doped ceria, are interpreted theoretically. Two different, experimental conditions are examined. First, the highly reduced surface of Sm0.2Ce0.8O1.9 – δ (SDC) is treated and the [Ce3+]s--P(O2) relations are evaluated. The experimental data are explained by a metallic surface layer, approximately neutral, i.e. with negligible transfer of charge to the bulk. The surface is metallic as the outer electrons on Ce3+ ions, which are small polarons when under low concentration, lose their localization under high concentration. Second, the surface of Pr0.1Ce0.9O2 – δ (PCO) is examined. The experimental data of [Pr3+]s--P(O2) relations are explained by a semiconducting, negatively charged, monomolecular surface layer forming a double layer with a positive bulk. In both SDC and PCO the surface defect concentration dependence on P(O2) is different from that of the bulk.
Comparing the Effects of Mechanical Activation and Fusible Additives on the Ionic Conductivity of Li1.3Al0.3Ti1.7(PO4)3
Authors: Shindrov A. A. , Kosova N. V.
Published: April 2024

The effects of mechanical activation in a planetary mill and the addition of fusible additives on the conduction properties of the Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte with the NASICON structure are compared. According to the results of impedance measurements, the mechanical activation increases the total conductivity of this material from 0.57 × 10–4 to 1.20 × 10–4 S cm–1, whereas the introduction of 5 wt % of fusible additives LiPO3 and Li2B4O7 increases the conductivity to 1.53 × 10–4 and 1.50 × 10–4 S cm–1, respectively. The electronic conductivity of samples does not exceed 10–9–10–8 S cm–1. According to the temperature dependence of the conductivity, the LATP sample containing Li2B4O7 (5 wt %) demonstrates the lowest activation energy equal to 0.29 eV.
One-Step Plasma-Assisted Electrochemical Synthesis of Nanocomposites of Few-Layer Graphene Structures with Manganese Oxides as Electrocatalysts for Oxygen Reduction Reaction
Authors: Kochergin V. K. , Manzhos R. A. , Krivenko A. G.
Published: April 2024

Using the method of plasma-assisted electrochemical exfoliation of graphite, a nanocomposite, which consists of few-layer graphene structures with surface decorated with manganese oxides nanoparticles, is synthesized in one-step process. It is found that this material exhibits a high electrocatalytic activity towards the oxygen reduction reaction due to the presence of manganese in the +2 and +3 oxidation states, and also carbonyl (quinone) functional groups on the surface of graphene structures.
Synthesis and Conductivity of Heterogeneous Compositions Bi4V2 – хFeхO11 – d/n% FeOу (m% Al2O3)
Authors: Krylov A. A. , Emel’yanova Yu. V. , Buyanova E. S. , Petrova S. A.
Published: April 2024

The structure and electrophysical characteristics of Bi4V2 – хFeхO11 – δ (BIFEVOX, where х = 0.3, 0.5) and its heterogeneous mixtures Bi4V2 – хFeхO11 – δ/n% FeOy and Bi4V2 – хFeхO11 – δ/m% Al2O3 are studied by varying their composition and the thermodynamic parameters of the environment. The crystallochemical parameters of individual compounds are calculated. The phase and elemental composition of samples is assessed using the XRD method and the scanning electron microscopy with energy-dispersive spectroscopic microanalysis; for individual phases, the absence of phase transitions is observed. The conductivity of materials is studied by the impedance spectroscopy. No composite effect is observed in these systems.
Proton and Oxygen-Ion Conductivity of the Pure and Lanthanide-Doped Hafnates with Pyrochlore Structure
Authors: Kolbanev I. V. , Baldin E. D. , Kasyanova A. V. , Medvedev D. A. , Shlyakhtina A. V. , Lyskov N. V.
Published: April 2024

In this work, a high-density ceramics Ln2Hf2O7 (Ln = La, Nd, Sm, Eu, Gd) were synthesized by mechanical activation followed by high-temperature synthesis at 1600°C (3–10 h) and their transport properties were compared with those of Ln2.1Hf1.9O6.95 (Ln = La, Nd, Sm, Eu) doped solid solutions. The total conductivity of ceramics was studied using impedance spectroscopy and dc four-probe method; for Ln2Hf2O7 (Ln = Sm, Eu), by determining the total conductivity as a function of oxygen partial pressure. The maximum oxygen-ion conductivity was observed for Gd2Hf2O7 (~1 × 10–3 S/cm at 700°C); it was shown to approach the conductivity of Gd2Zr2O7 (~2 × 10–3 S/cm at 700°C) for the first time. Thus, the gadolinium hafnate can be a promising material for further doping in order to obtain highly conductive electrolytes. Among pure rare-earth hafnates, the proton conductivity was reliably observed for Nd2Hf2O7 only; however, ac measurements detected low-temperature proton conductivity in the Gd2Hf2O7 up to 450°С as well. With a decrease in the lanthanide ionic radius, the oxygen-ion conductivity increased in the Ln2Hf2O7 (Ln = La, Nd, Sm, Gd) series. Although the conductivity of samarium hafnate is an order of magnitude lower than that of Gd2Hf2O7, it has a wide range of oxygen-ion conductivity (~10–18–1 atm at 700, 800°C); there is no contribution from hole conductivity in air, in contrast to Eu2Hf2O7. Among doped Ln2.1Hf1.9O6.95 pyrochlore solid solutions (Ln = La, Nd, Sm, Eu), the proton conductivity of ~8 × 10−5 S/cm at 700°C was shown in Ln2.1Hf1.9O6.95 (Ln = La, Nd). With a decrease in the lanthanide ionic radius, the proton conductivity disappeared; the oxygen-ion one, increased.
A Model Describing the Process of the Electrodeposition of Zinc Loose Deposits in Pulsed Current Modes
Authors: Nikitin V. S. , Ostanina T. N. , Rudoy V. M. , Ostanin N. I.
Published: April 2024

A phenomenological model describing the change in the structural characteristics of loose zinc deposits obtained in pulsed current modes is presented. Comparison of experimental data on the structural properties of deposits with the results of model calculations indicates the adequacy of the model. To describe the features of the dendritic deposit growth and to determine the duration of the homogeneous structure formation in pulsed modes, the concept of critical thickness is introduced, at which a sharp change in the loose deposit density occurs. The dependence of the zinc deposit critical thickness on the pulse duty ratio under pulsed current modes is determined. The increasing of the pulse duty ratio leads to denser deposits with rounded dendrite shapes and fewer growth points, as compared with the deposit obtained in galvanostatic mode.
Structure and Electrochemical Properties of Cathode Materials (Na3V2 ‒ xScx(PO4)3) for Sodium-Ion Batteries
Authors: Perfilyeva T. I. , Alekseeva A. M. , Drozhzhin O. A. , Antipov E. V.
Published: April 2024

Solid solutions Na3V2 − xScx(PO4)3 (0 x 2) are synthesized by the sol-gel method followed by annealing in inert atmosphere. The structure of Na3V2 − xScx(PO4)3 (x = 0.5, 1.2) compounds is studied by the method of powder X-ray diffraction. As the degree of substitution increases, the unit cell parameters and volume tend to increase on retention of the NASICON-type structure. The electrochemical properties of Na3V2 − xScx(PO4)3/C materials as the cathodes for sodium-ion batteries are studied in sodium half-cells in different potential intervals: 2.5−3.8, 2.5−4.5, and 1.0−4.5 V vs. Na/Na+. The charging curves of all materials demonstrate two plateaus: at ≈3.5 and ≈4 V vs. Na/Na+, corresponding to the successive transitions V3+/V4+ and V4+/V5+. However, the high-voltage plateau is reversible at the subsequent discharge only for the Na3V1.5Sc0.5(PO4)3/C material. This allows one to carry out the stable reversible cycling of this material in the potential interval of 1.0−4.5 V vs. Na/Na+ with the capacity higher than 170 mA h g−1, which corresponds to (de)intercalation of three Na+ per formula unit.
OXYGEN-ION COMPOSITES MWO4-SiO2 (M – Sr, Ba)
Authors: Pestereva N. N. , Guseva A. F. , Belyatova V. A. , Korona D. V.
Published: April 2024

Composite materials (1-f)SrWO4–fSiO2 and (1–f)BaWO4–fSiO2, where f is the volume fraction of the dispersed SiO2 additive, were prepared by the solid-phase method. The resulting composites were studied by XPA, TG-DSC, SEM-EDA. The electrical conductivity of the composites was measured by the electrochemical impedance method as a function of temperature, oxygen partial pressure in the gas phase, and composition. To estimate the contribution of ionic conductivity, the sum of ionic transfer numbers was measured by the EMF method. It has been shown that the addition of 20–25 vol % nano-SiO2 to low-conductivity oxygen-ion conductors SrWO4 and BaWO4 leads to an increase in the ionic conductivity of composites based on them by two orders of magnitude and by 12 times, respectively. The increase in conductivity in the systems under study is explained by the additional contribution of interfacial boundaries formed between the MeWO4 matrix and dispersoid nanoparticles. The mixing rule [1] was used to calculate the electrical conductivity of (1-f)SrWO4–fSiO2 and (1-f)BaWO4–fSiO2 composites depending on the SiO2 content. The calculated concentration dependences of the conductivity obtained are in satisfactory agreement with the experimental results.
The Analysis of Lithium Diffusion in the Cathode Material Particles of Primary Lithium-Manganese Cells by Measuring Electrochemical Noise and Magnetoresistance Relaxation.
Authors: Ukshe A. E. , Astafev E. A.
Published: April 2024

The process of lithium diffusion in the cathode material of lithium-manganese chemical power sources (CPS) after a short-term discharge are analyzed by an analyzing of the relaxation parameters of electrochemical noise and the magnitude of the magnetoresistance of the layer of injected lithium. It is shown that fluctuations in the diffusion flow of lithium are the source of electrochemical noise in such CPS. The data obtained also confirm the assumption made in the literature about the formation of a poorly conducting phase with a spinel crystal structure during the discharge of an element in the surface layer of MnO2 particles, which inhibits the diffusion process.
CARBON NANOPAPER PRODUCED FROM CARBON NANOTUBES/RESORCINOL-FORMALDEHYDE XEROGEL NANOCOMPOSITE FOR ELECTROCHEMICAL SUPERCAPASITORS
Authors: Krestinin A. V. , Knerel’man E. I. , Dremova N. N. , Golodkov O. N.
Published: April 2024

The nanocomposite of resorcinol-formaldehyde xerogel (RF-xerogel) and carbon nanotubes after carbonation at 800 °С was obtained in the form of composite carbon nanopaper (CCNP) with a thickness of 100-300 microns, a density from 0.1 g/cm2 to 0.5 g/cm2 and an electronic conductivity of more than 10 S/cm. According to the low temperature nitrogen adsorption data, the microporous structure of the nanopaper is formed by carbonized RF-xerogel, and the mesoporous structure is formed by the nanotube framework. The specific surface area of the nanopaper calculated by the method of nonlocal density function theory (NLDFT) exceeds 600 m2/g. The main contribution to the specific surface area of CCNP is made by pores with a width of ~ 0.7 nm, therefore, electrodes for a supercapacitor made of such paper are quite effective only in aqueous solutions of H2SO4 and KOH with small sizes of solvated ions. A technique for nanopaper activation with potassium hydroxide has been developed for the use of CCNP with organic electrolytes. The maximum specific surface area (NLDFT method) of activated CCNP reaches 1182 m2/g with a loss of carbon xerogel mass of ~ 25%. At the same time, the pore surface area of more than 1 nm width increases from 350 m2/g in CCNP to 685 m2/g in activated CCNP. Nanopaper has mechanical strength, pretty cheap and convenient for use in supercapacitors.
STUDY OF THE PROPERTIES OF COATINGS BASED ON COBALT-MANGANESE SPINEL OBTAINED BY THE METHOD OF NON-STATIONARY ELECTROLYSIS
Authors: Khramenkova A. V. , Yakovenko A. A. , Yuzhakova K. R. , Mishurov V. I. , Abdulvakhidov K. G. , Polozhentsev O. E.
Published: April 2024

Coatings based on cobalt-manganese spinel (Mn, Co)·(Mn, Co)2O4 were obtained on the surface of stainless steel by polarization with alternating asymmetric current. The study of the mechanical properties showed that the coatings are characterized by a sufficiently high adhesion to the substrate, their thickness is about 30 μm, and the microhardness value is 40 HV, which is comparable to similar oxide materials. The study of thermal stability in air shows their stability at temperatures up to 1000 °C, and the study of corrosion-protective properties - about the stability of the resulting coatings in a solution of 3.5% (wt.) NaCl.
ONE-STAGE ELECTROCHEMICAL SYNTHESIS OF A POLYMETHYLOLACRYLAMIDE/ULTRAFINE POLYTETRAFLUOROETHYLENE COMPOSITE
Authors: Kolzunova L. G. , Shchitovskaya E. V.
Published: April 2024

A method for one-stage electrochemical synthesis of a composite consisting of two non-conductive polymers has been developed. Using the example of electropolymerization of acrylamide in the presence of particles of ultrafine polytetrafluoroethylene (UPTFE), it is shown that the electrochemical approach makes it possible to simplify the traditional multistage technologies for the formation of composite polymer materials by combining in one process the electropolymerization of acrylamide and the formation of a polymethylolacrylamide (PMAA) film on the cathode, the capture of UPTFE particles by a growing polymer matrix, and formation of a PMAA/UPTFE composite. This technology makes it possible to reduce the total time for creating a polymer/polymer composite to 5-10 minutes. A procedure for the preparation of stable aqueous dispersions of UPTFE has been developed. It has been established that the most effective stabilizers of UPTFE aqueous dispersion are sodium lauryl sulfate (LS) and siloxane-acrylate emulsion SE 13-36. The formation of the PMAA/UPTFE composite was confirmed by XRD, SEM, SAXS, and spectrophotometry. It was found that the composite includes both large (~1 μm) and nanosized (1–10) nm UPTFE particles. The color of the PMAA/UPTFE composite films changes from colorless and transparent, characteristic of PMAA, to milky white (color of UPTFE and SE 13-36). This reduces the light transmission of composite films, reaching the minimum value for PMAA/UPTFE/SE 13-36. The mass of the PMAA/UPTFE composite increases with increasing electropolymerization time, and the residual current, which characterizes the degree of electrode insulation, decreases in comparison with the PMAA coating. Modification of the film with ultrafine polytetrafluoroethylene leads to a decrease in the swelling of composite coatings by a factor of 1.26–2.60, depending on the nature and concentration of the additive. The maximum insulating effect and reduced swelling is achieved for the PMAA/UPTFE(LS) composite, which indicates the preferred use of UPTFE(LS) for the modification of PMAA. The thermal stability of the PMAA/UPTFE(LS) composite and matrix PMAA is almost identical.