bluuebunny/crossref_metadata_2025 huggingface dataset:
An Ultralow Geomagnetic Field Intensity in The Mesoproterozoic Based on Studies of 1380 Ma Old Intrusive Bodies from the Udzha Aulacogen of the Siberian Platform
Authors: Shcherbakova V. V. , Pasenko A. M. , Zhidkov G. V. , Shcherbakov V. P. , Afinogenova N. A.
Published: April 2024

Abstract—Estimating the time of formation of the Earth’s solid inner core is a first–order problem in the thermal evolution of the Earth as a planet, which can be solved in particular by paleointensity (Banc) determinations. For this purpose, we have studied a collection of ~1380 Ma rocks sampled in the Udzha River valley within the Udzha aulacogen from the dolerite sill near the Khapchanyr River. The sill is an intrusion 5–7 meters thick that cuts through the siltstones and carbonates of the Udzha Formation. To obtain reliable paleointensity (Banc) determinations, magnetic and thermomagnetic properties of the studied rocks have been investigated, and their X–ray diffraction patterns and electron–microscopic images have been collected. It is shown that the carriers of the characteristic component of natural remanent magnetization are single–domain (SD) and small pseudo–single–domain (PSD) magnetite grains. Two methods have been used to determine the Banc: the Thellier–Coe procedure including reheating to lower temperatures (the pTRM checkpoints procedure) and the Wilson express method. Paleointensity determinations have been obtained for 9 samples (30 duplicates) that met the selection criteria. The mean value of Banc is extremely low and amounts to 4.54 ± 0.49 μT; the corresponding calculated value of the virtual dipole moment (VDM) is (11.1 ± 1.2) × 1021 Am2, which is almost an order of magnitude lower than the mean VDM in modern epoch (≈80 × 1021 Am2) and more than six times lower than the mean VDM in the Cenozoic (6.44 × 1022 Am2). The VDM data over the 350–3500 Ma interval presented in the world paleointensity database (WPD), Borok, have been analyzed. An alternation of periods of low and high paleointensity is observed in the Precambrian and Paleozoic, which indicates a large variability in the operation mode of the geomagnetic dynamo regardless of the existence or absence of an inner solid core of the Earth. It is important to note that the number of reliable VDM values over such a long interval, 350–3500 Ma, is too small for a complete statistical analysis to single out any time interval as the most probable for the formation of the inner core.
Staging of Occurrence of Seismicity Anomalies before Earthquakes in Kamchatka, Japan and Iceland
Authors: Smirnov V. B. , Petrushov A. A.
Published: April 2024

Abstract—The paper presents the results of a study showing that anomalies in the seismic regime parameters before earthquakes of various magnitudes occur in stages. The occurrence in stages means the correlation between the times of formation and development of anomalies in various seismic regime parameters. Earthquakes in regions with two general types of tectonics are selected for analysis: in the subduction zone (Kamchatka and Japan) and in the rift zone (Iceland). The selection of regions is primarily based on the availability and quality of regional seismic catalogs. GR b-value and the composite parameter known as the RTL are used as the seismic regime parameters. The detection of spatiotemporal anomalies before the selected earthquakes is based on the known “precursory patterns” of the seismic regime parameters. Comparing the durations of the detected anomalies shows that the anomalies of b-value generally occur earlier than the RTL anomalies. Possible reasons why the anomalies occur in stages are suggested. In the vicinity of the studied earthquakes, a change in the seismogenic rupture concentration parameter within the corresponding seismic cycles is also estimated. Comparing the times at which the detected seismic regime anomalies occur with the values of the seismogenic rupture concentration parameter corresponding to these times shows that the formation of seismic regime anomalies occurs at a stage when the system of seismogenic ruptures accumulated during the seismic cycle has almost reached its critical value.
Deep Electrical Conductivity Anomalies in the Chaun Bay Region Based on Magnetic Variation Sounding Data
Authors: Starzhinskii S. S. , Sormakov D. A.
Published: April 2024

Abstract—This paper discusses the results of magnetic variation soundings at two sites in the eastern Arctic, in the Chaun Bay region, at the Pevek and Valkarkai weather stations, by using the ModEM program to perform a three–dimensional (3D) inversion of tippers. The inversion has produced a geoelectric model of the region in a subsurface area of 300 × 300 × 200 km. The moduli of tippers at both sites have values between 0.2 and 0.85, reaching the maximum ones in a period of 1000 s. At the Pevek weather station, the real induction arrow in the Parkinson convention is oriented to the west throughout the range of periods. At the second site, its azimuth changes from 30° to the NE to –30° to the NW as the period of variations increases. Throughout the range of depths, conductive inhomogeneities are located to the west and north of the Chaun folded zone. They extend as a narrow strip under the western and northern coastal parts of the zone at depths of 8–12 km. As the depth increases, they are split into blocks, which reach their maximum size in the horizontal plane at depths ranging between 20 and 30 km. The most prominent among them is the conductive block beneath the southern part of the Chaun Bay. The roots of these blocks are distinguishable at depths of up to 100 km. The Chaun folded zone is represented by a high–resistance block down to a depth of 150 km with an electrical resistivity of more than 1000 Ω⋅m. Comparison of the obtained geoelectric model with the geophysical studies previously conducted here reveals a correlation between the location of conductive formations and the location of weakly positive anomalies in the gravity field in the Bouguer and isostatic reductions in the coastal water area.
Geophysical Effects of a Series of Strong Earthquakes in Turkey of February 6, 2023
Authors: Adushkin V. V. , Rybnov Yu. S. , Riabova S. A. , Spivak A. A. , Tikhonova A. V.
Published: April 2024

Abstract—During a series of destructive earthquakes in Turkey on February 6, 2023, in particular, two strong earthquakes with magnitudes 7.8 and 6.7 immediately following each other, the results of instrumental observations of microbaric and geomagnetic variations made in the surface layer of the atmosphere, as well as variations of the electric field and the critical frequency of the regular F2 layer of the ionosphere are presented. It is shown that the earthquakes were accompanied by variations of magnetic and electric fields, generation of infrasound waves recorded at a considerable distance from the sources, as well as variations of the critical frequency f0F2.
Contribution of the Photonic Component to the Ionization of the Atmosphere by Earth Crust Nuclides and Radioactive Emanations
Authors: Anisimov S. V. , Galichenko S. V. , Klimanova E. V. , Prokhorchuk A. A. , Afinogenov K. V.
Published: April 2024

Abstract—We investigate the contribution of gamma radiation of natural radionuclides constituting the Earth crust, radioactive emanations, and their decay product in the ground to the intensity of production of ion pairs in the atmosphere against the background of ionization of the atmosphere by radioactive gases flowing to the atmosphere from the ground and propagating together with their short-lived daughter products. The density of the radon flux to the atmosphere is estimated by three methods: the reservoir method, the integration of altitude profiles of volume activity of radon, based on gamma spectroscopic observation and diffusion model. The distribution of the gamma dose rate dose from the earth radionuclides in the soil and in the atmosphere is calculated using Gleant4 software. The propagation of the radon isotopes and their decay products in the atmosphere is calculated using large eddy simulations supplemented with kinematic simulations of the subgrid transport of a passive scalar. It is shown that depending on the specific activity of nuclides in the ground and the turbulent regime of the atmosphere, the total contribution of the γ-radiation to the ion pair production rate in the atmospheric boundary layer is approximately from 1% to 20% and increases upon a decrease in the penetrability of the upper ground layer for radioactive emanations.
Automated Assessment of Hazards of Aftershocks of the MW 7.8 Earthquake in Turkey of February 6, 2023
Authors: Baranov S. V. , Shebalin P.  N. , Vorobieva I. A. , Selyutskaya O.  V.
Published: April 2024

Abstract—This paper analyzes the use of the automated aftershock hazards assessment system (AFCAST) through the example of a series of aftershocks of the Mw 7.8 earthquake in Turkey of February 6, 2023 (the Pazarcik earthquake). The paper presents automated estimates of the aftershock activity area, the magnitude of the strongest aftershock, and the duration of the hazardous period, yielded using data on the main shock and on the first aftershocks.
Tectonic Aspects of the East Anatolian 06.02.2023 Earthquake in Turkey
Authors: Ҫelik Hasan , Trikhunkov Y. I. , Sokolov S. A. , Trifonov V. G. , Zelenin E. A. , Kargınoğlu Y. , Yushin K. I. , Lomov V. S. , Bachmanov D. M.
Published: April 2024

Abstract—During the East Anatolian earthquake with Mw = 7.8, which occurred on February 6, 2023 at 1:17 UTC, the 361 km long segment of the NE-trending East Anatolian active left-lateral fault zone (EAFZ) was activated. A left-lateral displacement took place at a distance of 318 km on formed seismic ruptures. Its maximum magnitude of 8.5 m is registered northward of the earthquake epicenter. To the northeast, the displacement of several meters is maintained over a significant length of the activated segment and is accompanied by uplift of the south-eastern side of the ruptured zone at up to 1.5 m. To the southwest of the maximum displacement area, the strike slip decreases from it at shorter distances compared to the northeastern part and the vertical component varies, although the southeastern side is mostly uplifted. In the terminal southwest, the strike slip is replaced by normal faults, gaping fractures, and other manifestations of transverse extension, which are accompanied by landslides and are mainly secondary seismic dislocations. Left lateral slip also occurred at the northern ends of the western and eastern branches of the Dead Sea Transform (DST), adjacent to the EAFZ from the south. Despite the fact that the energy distribution of numerous aftershocks along the EAFZ is generally proportional to the distribution of offsets on seismic ruptures, the slip on the EAFZ occurred during and immediately after the main shock. In the northern part of the DST, a significant decrease in the amount of energy released by strong earthquakes during the last centuries has been established. We consider that the tectonic stress accumulated in the northern part of the DST became the important geodynamic source of the East Anatolian 02.06.2023 earthquake.
On Determination of the Electrical Conductivity of a Local Inclusion of Piecewise-Constant Isotropic Medium
Authors: Krizskii V. N. , Aleksandrov P. N.
Published: April 2024

Abstract—This work is a continuation of the authors' research on solving inverse problems of mathematical geophysics in a linear formulation. Unlike previous works, where the solution was built on the basis of volumetric integral equations, boundary integral representations and emerging boundary integral equations are used here to solve the inverse coefficient problem of geoelectrics to find the constant electrical conductivity of a local isotropic inclusion, located in a piecewise-constant electrical conductivity isotropic enclosing medium.
Tectonophysical Zoning of Seismogenic Faults in Eastern Anatolia and February 6, 2023 Kahramanmaraş Earthquakes
Authors: Rebetsky Yu. L.
Published: April 2024

Abstract—The results of the tectonophysical reconstruction of stresses in the crust of Eastern Anatolia, obtained from the analysis of data on earthquake focal mechanisms, have shown that a significant restructuring of the stress state has occurred here in the last 20 years. It was largely confined to the southern and southwestern sectors of the region, covering hundreds of kilometers along the East Anatolian Fault. The data obtained from tectonophysical monitoring not only on the orientation of principal stresses, but also on their normalized values made it possible to calculate Coulomb stresses on faults. The results of fault zoning by intensity and sign of these stresses helped identify both hazardous sections close to the limit state and safe sections with negative Coulomb stress values. It has been established that in the region of the source of the first strong Pazarcık earthquake, which had a complex structure (three segments), there were extended sections with a critically high Coulomb stress level, separated by zones with low and even negative values of these stresses. The epicenter of this earthquake was located on the echelon fault within a section (first segment) with a high Coulomb stress level. The source of the second strong Elbistan earthquake was located on a fault with negative Coulomb stresses. The conducted analysis shows that this second Turkey earthquake may have been caused by stress changes that occurred in the crust of the region after the first strong earthquake. The research results show that Coulomb stresses in systems of closely located and differently oriented faults may be prone to sudden changes during the development of the earthquake on one of hazardous sections.
The RTL Anomaly of Seismicity before the February 6, 2023 Earthquake in Turkey
Authors: Smirnov V. B. , Petrushov A. A. , Mikhailov V. O.
Published: April 2024

Abstract—Based on the data from the regional Turkey earthquake catalog and the ANSS Comprehensive Earthquake Catalog for Turkey and a part of Iran, a posteriori analysis of RTL anomalies of seismicity before the damaging Mw7.8 Pazarcik earthquake in Turkey of February 6, 2023 and, for comparison, before the Mw 7.1 earthquake of October 23, 2011 (Eastern Turkey), the Mw 7.3 earthquake of November 12, 2017 (Iran), and the М 6.7 earthquake of January 24, 2020 (the East Anatolian Fault), was made. Distinctly observable before the Pazarcik earthquake is an RTL anomaly with well-marked stages of a seismic quiescence and subsequent activation near the epicentre of the future earthquake. Spatially, the anomaly is one-and-a-half times smaller than the source of the Pazarcik earthquake, and one-and-a-half - two times smaller than RTL anomalies before other regional earthquakes with a magnitude above 7. By size, it corresponds to the anomaly before the Mw 6.7 earthquake that occurred on the same fault. As a hypothesis to explain why the size of the anomaly before the Mw 7.8 Pazarcik earthquake does not match the sizes of the anomalies characteristic of M7+ earthquakes, it was assumed that the detected RTL anomaly reflects the formation only of the first, relatively small segment of the source of the Pazarcik earthquake.
Historical Earthquake on the North-Eastern Extension of the East Anatolia Fault
Authors: Tatevossian R. E. , Mokrushina N. G. , Ovsuchenko A. N , Larkov A. S.
Published: April 2024

Abstract—The position of the hypocenter and the magnitude of the earthquake of September 11/23, 1888 were determined based on macroseismic data published in the Russian press in Russian, Armenian and Georgian. Calculations showed that the magnitude of the earthquake was previously significantly underestimated, which is why it was not included in the catalog of strong earthquakes in the Caucasus test region [Shebalin and Tatevossian, 1997]. The accuracy of the location of the hypocenter makes it possible to identify the active fault with which the source of the 1888 earthquake is associated. The earthquake with Mw = 6.6 that occurred almost 100 years later confirms the long-term activity of the Western branch of the East Anatolian fault zone.
Laser Ablation of Styrene–Methacrylate Composites
Authors: Buzin N. V. , Mukhametova G. M. , Kholuiskaya S. N. , Kiselev A. V. , Kalinichenko V. N. , Gridnev A. A.
Published: April 2024

Various styrene–methacrylate composites with mineral fillers have been studied as a substrate for the deposition of copper tracks on surfaces after laser ablation. It has been revealed that both insufficient laser heating of the substrate with applied varnish and its overheating have a negative effect on chemical copper plating. The use of crosslinked styrene–methacrylate polymers makes it possible to achieve stable copper plating of the laser-treated surface of the varnish-coated substrate. It has been shown that with an appropriate selection of ablation parameters, finely divided minerals, such as talc, celadonite, aquamarine, shungite, chromia, and iron oxide (ocher), can be used as varnish filler for chemical copper plating of laser-treated parts of the substrate.
Photocatalytic Reduction of Carbon Dioxide in Aqueous Suspensions of a Titania Semiconductor
Authors: Dzhabiev T. S. , Avdeeva L. V. , Savinykh T. A. , Dzhabieva Z. M.
Published: April 2024

The photocatalytic reduction reactions of CO2 in aqueous suspensions of titanium dioxide (TiO2) semiconductor with photodeposited Pt and Cu cocatalysts have been studied. It has been found that the composition and amount of CO2 reduction products significantly depend on the nature of the cocatalyst supported onto TiO2. A mechanism for the formation of CO2 reduction products has been proposed.
Long Lived Delayed Fluorescence of Ternary Naphthalene–β-Cyclodextrin–Cyclohexane
Complexes at Room Temperature
Authors: Ionov D. S. , Ionova I. V. , Mazalov M. A. , Alfimov M. V.
Published: April 2024

Long-lived delayed fluorescence of dispersions of microcrystals of naphthalene–β-cyclodextrin–cyclohexane ternary complexes has been studied. It has been established that the delayed fluorescence is due to the T–T annihilation process. The kinetics of delayed fluorescence has a nonexponential character; the average lifetime is 0.68 s. The shape of the decay rate curves of delayed fluorescence does not depend on the intensity of excitation light. The nonexponential nature of the delayed fluorescence is presumably associated with the presence in the crystals of paired naphthalene molecules with different mutual positions and pair formation energies.
Influence of Ionization and Spin Transitions on Electron Delocalization
in the Molecules of Transition Metal Sandwich Complexes
Authors: Ketkov S. Yu. , Rychagova E. A.
Published: April 2024

A quantum-chemical study of the structures of symmetric 3d metal sandwich complexes with benzene and cyclopentadienyl ligands has been carried out within the framework of the electron density of delocalized bonds (EDDB) model. Neutral and ionized molecules in various spin states were considered. It is shown that successive population of the d-electron shell by varying the metal atom in a series of similar complexes, as a rule, leads to a decrease in the degree of electron density delocalization. The detachment of an electron from neutral molecules also reduces the number of delocalized electrons in the sandwich system, butthe contribution of the metal atom to delocalization increases in most cases. Singlet-triplet transitions in metallocenes and bis-benzene complexes decrease the electron density of delocalized bonds, but to a lesser extent than in the free and C6H6 ligands.
Evaluation of the Applicability of External X-ray Radiation to Stimulate the Autoradiolysis Processes in Therapeutic Radiopharmaceuticals (Exemplified by [153Sm]Sm-PSMA-617 and [177Lu]Lu-PSMA-617)
Authors: Mitrofanov Yu. A. , Bubenshchikov V. B. , Belousov A. V. , Lunev A. S. , Larenkov A. A.
Published: April 2024

The paper presents the results of a study on the radiolytic degradation of vector molecules in radiopharmaceuticals, caused by ionizing radiation from the radionuclide used in the preparations, in comparison with the equal dose of external X-ray irradiation. The dose factors for therapeutic radionuclides samarium-153 and lutetium-177 in aqueous solutions were estimated in geometry simulating the finished dosage form of radiopharmaceuticals (standard injection vial ) both by computational methods (in silico) and applying chemical dosimetry. Irradiation with external X-ray source to doses formed in volume of therapeutic radiopharmaceuticals with given radioactivity concentration was performed on an LNK-268 X-ray unit. Using the [153Sm]Sm-PSMA-617 and [177Lu]Lu-PSMA-617 radiopharmaceuticals as an instance, we compared the degree of radiolytic degradation and the profiles of radiolytic impurities formed as a result of both external X-ray irradiation and autoradiolysis. Qualitative coincidence of the impurity profiles formed in both cases was noted. It has been shown that external X-ray radiation can be used to simulate the autoradiolysis processes of radiopharmaceuticals if additional corrections are made for the type of radiation and dose rate.
Spectral-Luminescent Study of the Acid–Base Equilibrium of 5-Aminouracil and 6-Aminouracil in Aqueous Solutions
Authors: Ostakhov S. S. , Kayumova R. R. , Akhiyarov A. A. , Ivanov S. P. , Khursan S. L.
Published: April 2024

The spectral fluorescence characteristics of 5-aminouracil (5AU) and 6-aminouracil (6AU) in neutral and alkaline aqueous solutions have been studied. With the use of the density functional theory, it has been shown that uracils preferentially dissociate at the N1–H bond. The acid–base equilibrium constants pKa1(5AU) = 9.4 and pKa1(6AU) = 8.95 were determined by a fluorescence method. It was concluded that the ultrashort lifetime of the excited singlets of 5AU and 6AU prevents the measurement of the acid–base equilibrium constant of uracils in an electronically excited state.
Structure Modification and Enhancement of Wear Resistance of Ultra-High-Molecular-Weight Polyethylene by Low-Pressure Helium Plasma Treatment
Authors: Vasilets V. N. , Velyaev Yu. O. , Torkhov N. A. , Mosunov A. A. , Potopakhin L. V. , Evstigneev M. P.
Published: April 2024

The surface treatment of ultra-high-molecular-weight polyethylene (UHMWPE) in heliumplasma at a pressure of 0.133 mbar has been studied by IR spectroscopy, X-ray photoelectron spectroscopy,a nd atomic force microscopy. It has been shown that the helium plasma treatment leads to the formation of double bonds in the UHMWPE surface layer and the associated formation of intermolecular crosslinks. The crosslinking of the surface layer is accompanied by a decrease in the nanowear of the UHMWPE surface bymore than three orders of magnitude, which is confirmed by measurements using an atomic force microscope in the contact mode
Influence of High γ-Radiation Doses on the Germination and Toxic Properties of Oat Seeds
Authors: Allayarov S. R. , Allayarova U. Yu. , Klimanova E. N. , Demidov S. V. , Sashenkova T. E. , Blokhina S, V. , Mishchenko D. V.
Published: April 2024

The effect of γ-radiation doses from 100 to 3000 kGy on the toxic properties and germination of oat seeds has been + studied. A tendency has been noted for a 15–25% decrease in the germination of oat seeds under laboratory conditions in the range of presowing irradiation doses of 10–700 Gy. After irradiation with a dose higher than 1 kGy, the seeds lost their ability to germinate. Curves reflecting the dependences of the length of oat stalk on the dose of presowing irradiation of seeds exhibited two areas with a characteristic separation point at doses of 70 Gy, below which the degree of influence of the irradiation dose on the height ofseedlings and their growth ability increased noticeably. The toxicity of radiolyzed oat grains depended on the dose of γ-irradiation of grains and the mode of additional feeding of experimental mice. It was established that a γ-radiation dose lower than 100 kGy did not affect the toxicity of fodder oat grain, and radiation doses of 400 kGy or higher made irradiated grains unsuitable for feeding mice without additional feeding with compoundfeed. The higher the dose of γ-irradiation of oat grain, the earlier experimental mice died en masse: after 14–15, 9, 8, and 6 days of feeding at radiation doses of 580, 1000, 1700, and 3170 kGy, respectively. The reason for the toxic manifestation of irradiated oat grains and the death of mice treated with irradiated grain,apparently, can be the formation of toxic substances in oat grains irradiated with high doses due to the occurrence of physicochemical reactions in the course and after irradiation and a decrease in the nutritional value of products associated with the destruction of vitamins and other food components. Intoxication after consumption of oat grains irradiated with a dose of 400–3170 kGy was clinically manifested by depression, lethargy of animals, and signs of dehydration and diarrhea against the background of a strong decrease in the body weight of experimental animals. It is expedient to use radiolyzed oat grains for technical purposes, especially, if they were treated with high doses of radiation
On the Fabrication of Hydrophobic Coatings by Polycondensation of Fluoroalkylalkoxysilanes
Authors: Benderskii V. A. , Kim I. P. , Dremova N. N.
Published: April 2024

It has been shown that for obtaining hydrophobic coatings, it is reasonable to use fluoroalkylalkoxysilanes (FASs) with a longer fluoroalkyl chain than FAS-19, so that the F/Si molar ratio exceeds 5–6. It is proposed to purposefully change not only the chain length of oligomers, but also the structure of solutions from dilute colloidal solutions to structured gels, with the F/Si ratio being controlled. In the case of polycondensation of investigated fluoroalkylalkoxysilanes on a hydroxylated surface, a strong silicone framework is formed, which is chemically bonded to the surface and to fluoroalkyl chains oriented perpendicular to it
Ionization of Helium Atoms by Triply Charged Metal Atoms during Laser Ablation of Metals in Superfluid Helium
Authors: Boltnev R. E. , Karabulin A. V. , Krushinskaya I. N. , Pelmenev A. A. , Matyushenko V. I.
Published: April 2024

The applicability of laser ablation of metal targets for obtaining triply charged ions of metal atoms, including low-melting metals, has been experimentally demonstrated. By analyzing the luminescence spectra of a plasma plume during laser ablation of a metal target immersed in superfluid helium, the main channel for the formation of helium ions in plasma at a laser beam power density below the breakdown threshold of the helium medium has been determined. It has been shown that the ionization of helium atoms occurs in two steps, the formation of the HeM3+ ionic complex and the dissociation of the complex via its interaction with a metal atom.
Degradation of the Chromophore Functions of Dyes in Irradiated Solutions
Authors: Kholodkova E. M. , Ponomarev A. V.
Published: April 2024

Radiolysis damages the system of conjugated bonds and thus leads to the degradation of the chromophore functions of dyes in aqueous solutions. Ten representatives of quinophthalone, indigo, triphenylmethane, and azo dyes exhibited the same type of correlations between the absorbed dose and the degree of discoloration. It was shown using the method of competing scavengers that the color of aerated solutions decreased mainly due to the addition of OH radicals to the dyes. The radiation-chemical yields of discoloration ranged from 0.03 to 0.11 μmol/J and increased depending on the length of bond conjugation in the dye molecules. For practical electron-beam discoloration of dye solutions with a concentration of 20 mg/dm3, anabsorbed dose of 1–1.5 kGy was sufficient.
Photoinduced Room-Temperature Magnetism of Low Curie Temperature Cu–Ni Nanoparticles in Polymer Composites with Rubrene Microcrystals
Authors: Rumyantsev B. M. , Bibikov S. B. , Leontiev V. G. , Berendyaev V. I.
Published: April 2024

A relation has been established between the decrement of the low-field magnetic spin effect (measured by the luminescence of polymer films of composites with rubrene microcrystals), caused by the addition of magnetic Cu–Ni nanoparticles with a low Curie temperature (TC = 40–60°C), and the photoinduced particle magnetic moment exceeding the dark moment. Based on the study of the temperature dependence of the decrement and its comparison with the thermal demagnetization of the dark magnetic moment, a conclusion was made about a possible mechanism for the photothermal magnetization of nanoparticles
Photoprocesses in Guest–Host Complexes of a Styryl Dye Thio Derivative with Cucurbiturils
Authors: Svirida A. D. , Ivanov D. A. , Kryukov I. V. , Petrov N. Kh. , Aleksandrova N. A. , Avakyan V. G. , Gromov S. P.
Published: April 2024

Photoprocesses in aqueous solutions of the styryl dye 1-ethyl-4-{(E)-2-[4(methylthio)phenyl]vinyl}pyridinium perchlorate (1) and its complexes with cucurbit[n]urils (CB[n], n = 6–8) have been studied using the methods of stationary and time-resolved optical spectroscopy. The fluorescence intensity increases by approximately 3 times in 1 : 1 complexes of 1 and CB[6], whereas CB[7] has almost no effect on the fluorescence intensity. In 2 : 1 complexes with CB[8], the photocycloaddition reaction does not occur, with strong fluorescence quenching being associated with the formation of nonreactive dimers. The fluorescence decay kinetics of 1 has two characteristic times, 1.4 and ~130 ps, and changes little in the complexes. The photoinduced intramolecular charge transfer in 1 is an order of magnitude smaller than in the wellknown dye DASPI.
Calculation of the Molar Absorption Coefficients of InP, ZnS, and InP/ZnS Nanoparticles from the Complex Permittivities of the Corresponding Bulk Semiconductors
Authors: Tovstun S. A.
Published: April 2024

The molar absorption coefficients of spherical InP, ZnS, and InP(core)/ZnS(shell) nanoparticles have been calculated from the complex permittivities of the corresponding bulk semiconductors. The results are valid in the short-wavelength region of the absorption spectrum, where the quantum size effect is insignificant. For the imaginary part of the polarizability of core/shell nanoparticles, a formula has been obtained that is convenient for calculations in real numbers
Plasma Processing of Light- and Heavy-Oil Asphaltenes
Authors: Grin’ko A. A. , Ivanova L. V. , Frantsina E. V. , Petrova Yu. Yu. , Pak A. Ya. , Povalyaev P. V. , Kaichev V. V. , Arkachenkova V. V. , Litvintseva K. A.
Published: April 2024

The paper presents an analysis of the results of an experimental study of carbon materials obtained in a direct-current arc plasma from asphaltenes isolated from light oil of the Sredneugutskoye field and combined heavy oil from Venezuelan fields, as well as asphaltenes isolated from natural asphaltite. The influence of the composition of initial asphaltenes on the composition and properties of carbon materials obtained as a result of plasma treatment has been studied. The parent asphaltenes and carbon materials synthesized from them have been examined using a set of instrumental methods: X-ray diffraction, thermogravimetric analysis, energy-dispersive X-ray fluorescence analysis, Fourier-transform IR spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission and scanning electron microscopy, and laser diffraction. Changes in the composition and structure of the obtained materials after plasma processing of asphaltenes have been established. It is shown that this method can be considered promising for processing not only petroleum material, but also oil industry waste enriched in resin–asphaltene components.
Spectral Properties of Functional Distyryl Derivatives of BODIPY
Authors: Pakhomov A. A. , Efremova A. V. , Maksimova M. A. , Kononevich Yu. N. , Ionov D. S. , Dubinets N. O. , Martynov V. I. , Muzafarov A. M. , Alfimov M. V.
Published: April 2024

The photophysical properties of functional distyryl derivatives of dipyrrometheneboron difluoride (BODIPY) in various solvents have been studied. It was shown that in all solvents, the studied compounds have similar absorption and fluorescence spectra, which are characteristic of the distyryl derivatives of BODIPY. Small bathochromic shifts of the spectra with increasing solvent polarity, as well as insignificant changes in the rate constants of radiative and nonradiative processes, provide evidence that the S1 states are of the (π,π*) type. These dyes can be used to visualize processes in living systems.
Measurement of Photoelectrophysical Characteristics of Conductive Layers of CsPbBr3 Colloidal Quantum Dots
Authors: Pevtsov D. N. , Lochin G. A. , Katsaba A. V. , Brichkin S. B.
Published: April 2024

Colloidal quantum dots of perovskites having the chemical composition CsPbBr3 have been synthesized. For these particles, the average size of an ensemble of particles and sample polydispersity have been determined by steady-state spectrofluorometry. Conducting layers were made from the obtained particles, and the electrophysical characteristics of these layers were measured. The hole nature of the conductivity wasestablished, and the layer conductivity (0.04 S/m), mobility (0.8 cm2/(V s)), and number concentration of free charge carriers (3.01 × 1021 m−3) were measured. In accordance with published data, the measured mobility value is higher by one to two orders of magnitude than published typical values. It is shown that high polydispersity has a weak effect on the electrophysical and transport characteristics in the resulting layers.
Effect of Pulsed Electron Beam Treatment on the Release Profile of Chloramphenicol from Polylactic Acid–Based Polymeric Scaffolds
Authors: Volokhova A. A. , Ponomarev D. V. , Kurzina I. A. , Tverdokhlebov S. I.
Published: April 2024

The paper presents the results of testing the properties of antibacterial nonwoven fibrous materials based on polylactic acid with incorporated chloramphenicol. It has been shown that exposure to a pulsed electron beam increased the rate of release of chloramphenicol into a phosphate-buffered saline medium. In this case, the amount of the substance released from treated samples was reliably greater than that with untreated samples during the five days of the experiment
Effect of Gamma-Irradiation Dose on the Yield and Acute Toxicity of Seed Potato Tubers of the Meteor Variety
Authors: Allayarova A. S. , Shitikova A. V. , Faingol’d I. I. , Allayarova U. Yu. , Klimanova E. N. , Sashenkova T. E. , Demidov S. V. , Chekalina S. D. , Allayarov S. R.
Published: April 2024

The influence of the dose of presowing γ-irradiation of tubers on the anatomical and morphological structure, yield, and tasting properties of potatoes of the Meteor variety has been studied. Morphological disorders—beak-shaped and heart-shaped tubers of a large fraction and small tubers in the form of embryos—were found in potatoes grown from tubers irradiated with doses of 500–600 Gy, although no external anatomical and morphological differences were noted in the stems and leaves of potato plants in the course of the vegetative development regardless of the presowing irradiation dose of tubers. Irradiation of seed tubers with doses of 200–300 Gy led to the highest yield and profitability and the best tasting qualities of grown potatoes. Experiments on the toxicity of potato tubers irradiated with doses of 100–1500 kGy and juice released during their radiolysis with doses of 1200–5000 kGy showed no negative effect on the animals that consumed them. At the same time, the physiological processes of digestion, excretion, and metabolism in experimental animals were not inhibited and the level of glucose in their blood remained within physiological reference values. The experimentally established highest doses of γ-irradiation of potatoes and the doses of introducing aqueous dispersions of the irradiated products into mice (gram of substance per 1 kg of live weight of the animal) that did not cause clinical manifestations were 10 g/kg for powdered potato tubers irradiated with a dose of 1500 kGy and 20 g/kg for dried juice powder released in the course of irradiation of potato tubers with a dose of 2000 kGy.
Production of Low-Molecular-Weight Organic Components by the Microwave Pyrolysis of Peat
Authors: Alyeva A. B. , Ananicheva S. A. , Glyavin M. Yu. , Denisenko A. N. , Zelentsov S. V. , Krapivnitskaya T. O. , Peskov N. Yu. , Sachkova A. A.
Published: April 2024

A facility for conducting experiments on the microwave (MW) pyrolysis of peat at a source operating frequency of 2.45 GHz has been developed. The MW pyrolysis of peat for the production of low-molecular-weight organic components has been experimentally studied. The products of peat MW radiationinduced decomposition were determined, and reaction schemes for the degradation of peat components were proposed. A carbonaceous residue with relative carbon, hydrogen, nitrogen, and sulfur contents of 83–85, 4–5, 2–3, and 0.3 wt %, respectively, was obtained.
Surface Properties of Gamma-Irradiated Polypropylene
Authors: Bogdanova S. A. , Shaimukhametova I. F. , Galimzyanova R. Yu. , Khakimullin Yu. N. , Rudneva T. N. , Demidov S. V. , Allayarov S. R.
Published: April 2024

polypropylene (PP) has been studied as a function of the absorbed dose. It has been established that γ-irradiation leads to an increase in the free surface energy of the polymer, its acid–base component, and the surface polarity. An analysis of the IR spectra of γ-irradiated PP samples indicated the formation of oxygen-containing groups in the composition of PP macromolecules, which was confirmed by the values of the surface acidity parameter. An increase in the dose led to an increase in the concentration of products of radiation-induced conversion. A significant increase in the melt flow index (MFI) of polypropylene up to an absorbed dose of 150 kGy also evidenced the occurrence of oxidation and destruction processes. The MFI decreased at radiation doses above 150 kGy, and this fact indicates that such doses of ionizing radiation lead to the predominance of the processes of polymer structuring or crosslinking.
Observation of a Plasma Analogue of the Mpemba Effect
Authors: Dekhtyar’ V. A. , Dubinov A. E. , Kolesov G. N.
Published: April 2024

The processes of freezing of water droplets sitting on a substrate after exposure to nanosecond spark discharges have been experimentally studied. It has been found that the droplets subjected to spark discharge treatment freeze much earlier than those unexposed to discharges. The analogy of the observed processes with the well-known Mpemba effect is noted. A qualitative explanation is given for the observed effect: rapid freezing is due to hydrated electrons, which are formed upon contact of water with plasma and play the roleof crystallization centers
Fourier Transform IR Spectroscopic Study of the Influence of a High Dose of Gamma Radiation on the Composition of Functional Groups in Potato Tubers
Authors: Demidov S. V. , Rudneva T. N. , Allayarova U. Yu. , Klimanova E. N. , Allayarova A. S. , Shitikova A. V. , Chekalina S. D. , Allayarov S. R.
Published: April 2024

This article considers physicochemical changes in the composition of potato tubers gamma-irradiated to doses of 5000 kGy, as studied by Fourier transform IR spectroscopy. Functional groups in the powders of skin, pulp, and juice of irradiated tubers have been examined. The carbonization and radiationinduced oxidation of the molecules of tuber constituents have been established. At doses above 1000 kGy, the hardness of tubers was completely lost, the integrity of the skin surface was violated, and an intense release ofjuice began. It has been found that γ-radiolysis at a dose to 5000 kGy does not lead to the complete destruction of chemical bonds in the structure of the main compounds contained in potato tubers.
Photoprocesses of Bisthiacarbocyanine Dyes in the Presence of Cucurbit[7,8]urils in Water
Authors: Fedotova T. V. , Zakharova G. V. , Chibisov A. K.
Published: April 2024

Spectral, spectral–kinetic, and photochemical properties of bisthiacarbocyanine (bis-TCC) dyes, based on 3,3′-dimethylthiacarbocyanine perchlorate, in water have been studied. The existence of two bis-TCC forms absorbing in the long-wavelength (monomeric form) and short-wavelength (dimeric form) spectral regions has been revealed. The monomeric form of bis-TCC is capable of fluorescence, photoisomerization, and transition to the triplet state. The dimeric form is characterized by effective intersystem crossing, the almost complete absence of fluorescence, and photoisomerization. Both the monomeric and dimeric forms of bis-TCC undergo complexation with cucurbit[7,8]urils. Complex formation leads to an increase in the fluorescence intensity of the monomeric and dimeric forms and increases the yield of delayed fluorescence and the lifetime of the dimeric form in the triplet state and those of the photoisomer of the monomeric form. The dimeric form of bis-TCC in the triplet state is capable of entering into the photooxidation reaction with p-itroacetophenone both in the absence and in the presence of cucurbit[7,8]urils
Flame Detectors Based on Semiconductor Nanocrystals
Authors: Pevtsov D. N. , Demkin D. V. , Katsaba A. V. , Gadomska A. V.
Published: April 2024

The possibility of using semiconductor nanocrystals in photodetectors for optical detection of open flame has been explored. The spectral range boundaries of response of flame detectors have been concretized. In accordance with this, colloidal lead sulfide nanocrystals absorbing in the range of 1–1.5 μm have been synthesized. Photoresistors with different ligand compositions have been made from these particles. For the obtained samples, the current–voltage characteristics were measured and the photosensitivity and specificdetectivity parameters were calculated. A theoretical estimate of the flame detection range has been made for the samples. It has been shown that a photosignal can be reliably detected at a distance of more than 80 m.
Nitration of Phenol with Water Activated by Pulsed Hot Plasma Radiation
Authors: Piskarev I. M.
Published: April 2024

The nitration of phenol with plasma-activated water (PAW) generated by pulsed radiation of an electric spark discharge has been studied. Long-lived nitrogen-containing active species that accumulate in water during treatment are nitrous acid and the …ONOOH/ONOO− complex, which decomposes into peroxynitrite and peroxynitrous acid. Their concentration in PAW after 10 min of treatment was ~10−3 mol/L. When PAW is mixed with phenol in a 1 : 1 ratio, the identified reaction product is 4-nitrophenol. The yieldof nitration through PAW is equal to the nitration yield by the direct action of hot plasma radiation on a phenol solution.
About Some Peculiarities of Positron Annihilation and Sorption Methods in Microporosity Studies on Polymers
Authors: Shantarovich V. P. , Bekeshev V. G. , Kevdina I. B. , Gustov V. V. , Belousova E. V.
Published: April 2024

Data on microporosity (micropore size distribution) in the range from several angstroms to several nanometers, obtained by measuring the positron annihilation lifetime (PALS method) and by measuring CO2 sorption (low-temperature gas sorption, LTGS) are collated for a number of polymers with amorphous (polyetherimides, PEI) and semicrystalline (polyphenylene oxides, PPO) structures. The microporosity estimates based on the positron annihilation and CO2 sorption data are compared with published data obtained bothexperimentally and by the group contribution method for the permeability of these materials. The discrepancies found and their possible causes are discussed.
Synthesis and Properties of a Carbon Monoxide Oxidation Catalyst Based on Titanium Dioxide and Platinum Nanoparticles
Authors: Vershinin N. N. , Balikhin I L. , Kurkin E. N. , Kabachkov E. N. , Shulga Yu. M.
Published: April 2024

Carbon monoxide oxidation catalysts comprising Pt clusters on titanium dioxide with an oxide particle size of 6 and 20 nm have been synthesized. The catalysts have been studied using TEM, XRD, and XPS techniques, and it has been found that platinum clusters coated with a mixture of platinum oxides are formed on the support surface. The coherent scattering region of the Pt cluster is close to 5–6 nm for the studied oxide supports. The catalytic properties in the CO oxidation reaction at 295 K and low CO concentrations(less than 100 mg/m3) have been examined. The catalyst based on titania with a particle size of 20 nm and a platinum loading of 10 wt % has been found to have the CO oxidation rate 100 times higher than that on platinum black with a specific surface area of 30 m2/g. The catalysts are promising for use in catalytic air purification systems.
Single- and Double-Pulse Laser Kinetic Spectroscopy of Indoline Spiropyran
Authors: Atabekyan L. S. , Chibisov A. K. , Svyatoslavskaya T. A. , Svyatoslavskii N. L. , Markelov V. P.
Published: April 2024

Phototransformations of 6-nitro-8-methoxy-substituted indoline spiropyran in acetonitrile have been studied by laser kinetic spectroscopy (laser photolysis) with single- and double-pulse excitation. The role of the triplet state in the kinetics of photocoloration of spiropyran has been revealed. It has been shown that photochromic transformations of spiropyran involve unstable trans-isomers (conformers) of the open merocyanine form of spiropyran. Data on the transformation kinetics of the trans-isomers are presented.
Effect of Protonation on the Spectral–Luminescent and Photochemical Properties of a Bis(styrylbenzoquinoline) Dyad with the Naphthylene Framework and of Corresponding Dibenzoquinolylcyclobutane
Authors: Sulimenkov I. V. , Budyka M. F. , Li V. M. , Potashova N. I. , Gavrishova T. N. , Kozlovskii V. I.
Published: April 2024

The photophysical and photochemical properties of the protonated forms of both covalently bound biphotochromic dyad D44N containing two styrylbenzo[f]quinoline (SBQ) photochromes and corresponding cyclobutane CB44N containing two benzo[f]quinoline (BQ) substituents have been studied. CB44N is formed from D44N as a result of a reversible [2+2] photocycloaddition (PCA) reaction. The dyad and cyclobutane contain the 3-hydroxy-2-naphthoic acid (NA) moiety as a bridging group. It has been shown that the protonation of nitrogen atoms in the SBQ and BQ groups leads to bathochromic shifts in the absorption spectra and bathofloral shifts in the fluorescence spectra of the dyad and cyclobutane. In the protonated dyad, the quantum yield of the PCA reaction decreases, presumably due to the Coulomb repulsion, which prevents the cations of the protonated SBQ photochromes from approaching each other. In protonated cyclobutane, the quantum yield of the reverse four-membered ring opening reaction (retro-PCA), on the contrary, increases due to the absence of a competitive process of energy transfer from BQ to NA, which was previously observed in neutral cyclobutane
Thickness of the Modified Polymer Layer Formed by Low-Temperature Plasma Treatment
Authors: Gilman A. B. , Piskarev M. S. , Kuznetsov A. A.
Published: April 2024

Experimental data presented in the literature on the depth of processing of polymer films using low-temperature plasma are considered. Changes in the chemical composition and structure along the depth of the samples have been studied using the modern experimental techniques of X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission electron microscopy; precision etching was carriedout with an Ar+2500 cluster beam; and the pit depth was measured by profilometry. It has been found that the thickness of the modified layer is ≤50 nm and depends relatively little on the polymer nature.