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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Гохфельд, Денис Михайлович, Шаломов С. Ю., Сультимов Д. Б., Петров, Михаил Иванович
Заглавие : Самопроизвольное вращение магнитов, левитирующих над высокотемпературным сверхпроводником
Колич.характеристики :7 с
Место публикации : Сверхпроводимость: фунд. и приклад. исслед. - 2024. - № 1. - С. 34-40. - ISSN 29495644 (ISSN), DOI 10.62539/2949-5644-2024-0-1-34-40; Supercond. Fund. Appl. Res. - ISSN 29495660 (eISSN0
Примечания : Библиогр.: 11. - Авторы выражают благодарность А.Л. Фрейдману за создание сверхпроводящей платформы, С.В. Семенову за помощь с температурными измерениями, а также С.В. Комогорцеву за полезные обсуждения
Аннотация: Левитация постоянного магнита цилиндрической формы над высокотемпературным сверхпроводником, охлаждаемым жидким азотом, сопровождается спонтанными колебаниями, переходящими во вращение. Причиной вращения является неоднородность намагниченности магнита, вызванная градиентом температур вдоль вертикальной оси. Проведен эксперимент по левитации магнитов Nd–Fe–B над композитным высокотемпературным сверхпроводником. Результаты эксперимента подтверждают, что частота вращения зависит от намагниченности верхней и нижней половин магнита. Предложены способы контроля частоты вращения левитирующего магнита.Levitation of a cylindrical permanent magnet over a high-temperature superconductor cooled by liquid nitrogen can be accompanied by spontaneous oscillations and rotation. The reason for spontaneous rotation of the magnet is magnetization inhomogeneity induced by the temperature gradient. An experiment was carried out on the levitation of Nd–Fe–B magnets over a composite high-temperature superconductor. The experimental results confirm that the rotation frequency depends on the difference in the magnetization values in its upper and lower halves of the magnet. Methods for controlling the rotation frequency of a levitating magnet are proposed.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Udod L. V., Aplesnin S. S., Zelenov F. V., Sitnikov M. N., Molokeev M. S., Romanova O. B.
Заглавие : Enhancement of the magnetoelectric effect in the Bi2Fe4O9/BiFeO3 composite as a result of dipole and migration polarization in mullite
Колич.характеристики :13 с
Место публикации : J. Mater. Sci. - 2024. - Vol. 59, Is. 24. - P.10763-10775. - ISSN 00222461 (ISSN), DOI 10.1007/s10853-024-09885-x. - ISSN 15734803 (eISSN)
Примечания : Cited References: 55
Аннотация: The effect of the size of Bi2Fe4O9 and BiFeO3 nanoparticles on the magnetoelectric interaction in the Bi2Fe4O9/BiFeO3 composite with a percentage ratio of 67/33 has been studied. The electrostriction and electric polarization on electric and magnetic field in wide temperature range has been measured. The hysteresis of the polarization and I?V characteristics has been found. Temperature ranges with activation and hopping types of conductivity have been found. The mechanism of electric polarization and the crossover temperature from dipole polarization to migration polarization at 260 K have been established. Linear and quadratic contributions to the magnetoelectric effect have been found. Below 120 K the linear contribution is an order of magnitude greater than the quadratic contribution and above 240 K the quadratic contribution to the ME effect prevails. Models have been proposed to explain the enhancement of the magnetoelectric effect as a result of the migration polarization in mullite and linear magnetoelectric effect in bismuth ferrite. The correlation of temperatures of the extremum of the temperature coefficient of the electrical resistance and the magnetic phase transition in mullite at 260 K indicates a polaron-type conductivity and a strong electron?phonon interaction. A change in the sign of the electrostriction coefficient upon heating and the compression temperature of the composite in an electric field was found.
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3.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Важенина, Ирина Георгиевна, Столяр, Сергей Викторович, Комогорцев, Сергей Викторович, Ли О.А., Исхаков, Рауф Садыкович, Великанов, Дмитрий Анатольевич, Черемискина, Елена Владимировна, Немцев, Иван Васильевич
Заглавие : Исследование композиционных покрытий Fe-C, Co-C и Ni-C статическими и динамическими методами
Коллективы : Байкальская международная конференция "Магнитные материалы. Новые технологии", "Магнитные материалы. Новые технологии", Байкальская международная конференция, "Magnetic materials. New tecnologies", Baikal International Conference, Иркутский государственный университет
Место публикации : Магнитные материалы. Новые технологии: тез. докл. IX Байкал. междунар. конф. BICMM-2023/ чл. прогр. ком.: S. S. Aplesnin [et al.] ; чл. орг. ком. R. S. Iskhakov [et al.]. - Иркутск, 2023. - С. 73. - ISBN 978-5-962402178-0
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4.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Исхаков, Рауф Садыкович, Важенина, Ирина Георгиевна, Столяр, Сергей Викторович, Яковчук, Виктор Юрьевич
Заглавие : ФМР и СВР в планарных композиционных структурах
Коллективы : Байкальская международная конференция "Магнитные материалы. Новые технологии", "Магнитные материалы. Новые технологии", Байкальская международная конференция, "Magnetic materials. New tecnologies", Baikal International Conference, Иркутский государственный университет
Место публикации : Магнитные материалы. Новые технологии: тез. докл. IX Байкал. междунар. конф. BICMM-2023/ чл. прогр. ком.: S. S. Aplesnin [et al.] ; чл. орг. ком. R. S. Iskhakov [et al.]. - Иркутск, 2023. - С. 26. - ISBN 978-5-962402178-0
Примечания : Библиогр.: 6
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tsyganova S. I., Yu. Fetisova O., Velikanov D. A., Taran O. P.
Заглавие : Structural, magnetic and electrochemical characteristics of Ni/C composites fabricated from modified hydrolytic lignin
Колич.характеристики :3 с
Место публикации : Mater. Lett. - 2023. - Vol. 352. - Ст.135120. - ISSN 0167577X (ISSN), DOI 10.1016/j.matlet.2023.135120. - ISSN 18734979 (eISSN)
Примечания : Cited References: 11. - The present work was supported by the Russian Foundation for Basic Research , the Government of the Krasnoyarsk Territory and carried out as part of the budget project ( 0287-2021-0017 ) of the Institute of Chemistry and Chemical Technology SB RAS
Аннотация: The synthesis of metal–carbon materials based on hydrolytic lignin by its modification with subsequent carbonation is studied. It is shown the modification of hydrolysis lignin with ZnCl2 and NiCl2 leads to a significant increase of specific surface area up to 716 m2/g and the apparent specific capacity up to 350F/g of carbonized composite. It was found out that fabricated Ni/C composites are characterized by a coercive force of 80–105 Oe, a saturation magnetization of 4–11 Gs•cm3/g, and a residual magnetization of 0.28–0.45 Gs•cm3/g. This indicates the prospects of their use as a magnetically soft material.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Udod L. V., Aplesnin S. S., Sitnikov M. N., Eremin E. V., Molokeev M. S., Shabanov A. V., Romanova O. B., Kharkov A. M.
Заглавие : Structural and magnetic transitions in the Bi2Fe4O9/BiFeO3 composite
Место публикации : J. Alloys Compd. - 2023. - Vol. 958. - Ст.170445. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2023.170445. - ISSN 18734669 (eISSN)
Примечания : Cited References: 51
Аннотация: A Bi2Fe4O9/BiFeO3 composite with a percentage ratio of 67/33 has been synthesized, its morphological analysis has been carried out. The average crystallite sizes for each phase have been determined. The magnetization hysteresis has been established and the temperature of its disappearance has been found. Using the infrared absorption spectra, temperatures of the magnetic phase transitions in each phase have been determined from the magnetic susceptibility, magnetostriction constant, ultrasound damping coefficient, and phonon mode softening. The change of magnetostriction constant sign observed in the vicinity of the spin reorientation transition and antiferromagnetic transition in mullite has been attributed to the change of the sign of the magnetoelastic constants. The interaction between the phases in the composite and the correlation of its structural and magnetic properties have been established.
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volkova I. R., Tyryshkina L. E., Volochaev M. N., Zaloga A. N., Shabanova K. A., Ovchinnikov A. V., Lyamkin A. I.
Заглавие : The effect of aluminum-oxide powders on the structure and properties of copper electrodeposited composite coatings
Место публикации : Prot. Met. Phys. Chem. Surf. - 2023. - Vol. 59, Is. 1. - P.71-75. - ISSN 20702051 (ISSN), DOI 10.1134/S2070205122700022. - ISSN 2070206X (eISSN)
Примечания : Cited References: 9
Аннотация: Copper electrodeposited composite coatings containing two types of aluminum-oxide powders with different dispersities (alumina Al2O3-1 and electroexplosive aluminum-oxide nanopowder Al2O3-2) are obtained during the work. The studies show that introducing the powders leads to a change in the microstructure of the composites and a change in the grain growth principles during the formation of the coatings. Refinement and ordering of the grain structure of the coatings occurs and twinning defects and texture are formed. The change in the formation of the microstructure of the composites leads to a change in some operational characteristics: an increase in the microhardness (by 10% in the composites with the addition of alumina and by more than 30% in the coatings with electroexplosive aluminum oxide) and ultimate tensile strength (by 20% in the composites with Al2O3-1 and almost 1.5-fold in the samples with Al2O3-2).
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8.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Udod L. V., Aplesnin S. S., Sitnikov M. N., Romanova O. B.
Заглавие : Synthesis of the Bi2(Sn0.7Fe0.3)2O7-x/Bi2Fe4O9 composite and dielectric properties
Коллективы : "Actual problems of solid state physics", International scientific conference, "Актуальные проблемы физики твердого тела", международная научная конференция, Научно-практический центр по материаловедению НАН Беларуси
Место публикации : X International scientific conference “Actual problems of solid state physics": Book of abstracts/ int. sci. com. S. S. Aplesnin [et al]. - Minsk, 2023. - Sect.: Physical and chemical technologies. - P.349. - ISBN 978-985-7299-65-2
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Morozov E. V., Il’ichev A. V., Bouznik V. M.
Заглавие : Magnetic resonance imaging study of water absorption of polymer composite materials subjected to mechanical and temperature impact
Колич.характеристики :9 с
Место публикации : Russ. J. Phys. Chem. B. - 2023. - Vol. 17, Is. 6. - P.1361-1369. - ISSN 19907931 (ISSN), DOI 10.1134/S1990793123060064. - ISSN 19907923 (eISSN)
Примечания : Cited References: 18. - The research was carried out as part of a state assignment of the Institute of Chemistry and Chemical Technology of the Siberian Branch of the Russian Academy of Sciences (project no. 0287-2021-0012) using the equipment of the Krasnoyarsk Regional Center for Collective Use of the Federal Research Center "Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences"
Аннотация: The results of a study of water absorption processes by samples of polymer composite materials (PCMs) based on fiberglass, subjected to low-speed impact with controlled impact energy and alternating temperature cycling are presented. Using magnetic resonance imaging (MRI), the distribution of absorbed water in the fiberglass structure is visualized and the dynamics of its accumulation in various areas of the sample are studied. It is found that mechanical impact leads to a nonuniform distribution of the absorbed water in the samples and a significant accumulation of free water in the areas of destruction and adjacent layers in the event of a violation of the integrity of the outer layer of the material. It is shown that cyclic alternating temperature effects do not lead to a noticeable change in the water absorption processes and are comparable in effect to mechanical nondestructive impacts. The results obtained using MRI are in close agreement with the data of traditional weight measurements, which shows the effectiveness of the method in diagnosing defects and mechanical damage to PCMs exposed to the humid environment.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Udod L. V., Aplesnin S. S., Sitnikov M. N., Romanova O. B.
Заглавие : Investigation of the magnetoelectric effect and thermoelectric power of the composite of iron-substituted bismuth pyrostannate Bi2(Sn0.7Fe0.3)2O7/Bi2Fe4O9
Колич.характеристики :7 с
Место публикации : Phys. Solid State. - 2023. - Vol. 65, Is. 8. - P.1305-1311. - ISSN 10637834 (ISSN), DOI 10.21883/PSS.2023.08.56576.83. - ISSN 10906460 (eISSN)
Примечания : Cited References: 45
Аннотация: The composite compound Bi2(Sn0.7Fe0.3)2O7/Bi2Fe4O9 in the ratio 91/9% was synthesized by the solid-phase reaction method. The current-voltage characteristics were studied in the temperature range 800–400 K. The hysteresis of the current-voltage characteristics was found. The magnetoelectric interaction and thermoelectric power have been studied. The temperatures of predominance of the even and linear functions of the magnetoelectric effect are established. The sign change of the thermopower has been found.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pan, Xiaoqin, Li, Wei, Fang, Yueping, Zhang, Haoran, Xiao, Yong, Molokeev M. S., Ping Jiang, San, Liu, Yingliang, Lei, Bingfu
Заглавие : Semi-artificial photosynthetic system based on TiO2/Chlorophyll composite and microalgae for N2 fixation
Колич.характеристики :9 с
Место публикации : Chem. Eng. J. - 2023. - Vol. 475. - Ст.146179. - ISSN 13858947 (ISSN), DOI 10.1016/j.cej.2023.146179. - ISSN 18733212 (eISSN)
Примечания : Cited References: 45. - The work was supported by the National Natural Science Foundations of China (No. 12274144), the Ministry of Science and Technology of China (No. G2021030022L), the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (No. 2022KJ122, 2023KJ122), the Key Realm R&D Program of Guangdong Province (No. 2021B0707010003), the Guangzhou Science & Technology Project (No. 202103000059), the Guangdong Provincial Science and Technology Project (No. 2021A0505050006), and the Project of GDUPS (2018) for Prof. Bingfu LEI
Аннотация: Significant process has been made on the development of semi-artificial photosynthesis catering to the production of H2– and CO2– derived value-added products. But there are little reports on the application of semi-artificial photosynthetic system to nitrogen fixation areas. In this study we report the successful and highly efficient N2 fixation in one step at room temperature and ambient pressure by constructing new semi-artificial photosynthetic systems based on material-cell hybrids and microbial photo-electrolysis cells (MPECs). Improved TiO2/Chlorophyll composite that annealed at 400 °C was selected as electron donator to replenish additional electrons to Nostoc commune Vauch microalgae cell for N2 fixation. Ubiquinone-0 (2,3-dimethoxy-5-methyl-1,4-benzoquinone, Q0) was selected as electron relay that guarantees efficient transmission of electrons from abiotic material to microalgae cells. Determined by an ammonia assay kit, at constant concentration of microalgae, the constructed material-cell hybrid system photosynthetically synthesized 40.67 μM/h ammonia, while H-shape MPECs synthesized 132.70 μM/h, 19.23 times higher than that produced by pure microalgae. Using 15N2 as the reduction gas, the constructed H-shape MPECs photosynthetically synthesized 28.37 μM/h 15NH4+, 2.80 time higher than that of the MPECs without Q0 as electron relay.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sukhanova, Anna, Boyandin, Anatoly, Ertiletskaya, Natalya, Shalygina, Taisia, Shabanov A. V., Vasiliev, Alexander, Obvertkin, Ivan, Brott, Valeria, Prokopchuk, Yulia, Samoilo, Alexander
Заглавие : Composite polymer granules based on poly-ε-caprolactone and montmorillonite prepared by solution-casting and melt extrusion
Колич.характеристики :20 с
Место публикации : Polymers. - 2023. - Vol. 15, Is. 20. - Ст.4099. - ISSN 20734360 (eISSN), DOI 10.3390/polym15204099
Примечания : Cited References: 45. - This research was supported by a grant from the Russian Science Foundation, project No. 23-16-00184
Аннотация: Eco-friendly polymer composites in the form of granules based on biodegradable polycaprolactone (PCL) with the inclusion of montmorillonite (MMT) from 5 to 50 wt% were prepared by solution-casting and melt extrusion. The physicochemical properties of the composite granules were studied using FTIR spectroscopy, XRDA, DSC, and TGA methods. The paper presents comparative values of crystallinity of composite granules which depend on the method of measuring (XRDA, DSC). It was shown that the crystallinity of PCL/MMT granules was affected by the preparation method and by the MMT content, and that with increase in MMT content, crystallinity increased by up to 61–67%. The change in crystallinity of the granules also affected its biodegradation in soil. At the end of exposure in soil, the mass loss for the granules prepared by solution-casting was more than 90%, whereas for the composite granules prepared by extrusion it was less than 60%. Applying melt extrusion enabled obtaining intercalated composites with predictable features, whereas only mixed-structure microcomposites could be prepared by solution-casting.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ronzhin N. O., Posokhina E. D., Mikhlina E. V., Shestakov N. P., Nemtsev I. V., Bondar V. S., Ryzhkov I. I.
Заглавие : The effect of copper and iron adsorption on the catalytic performance of alumina nanofiber / nanodiamond composite in sensing applications
Место публикации : J. Phys. Chem. Solids. - 2022. - Vol. 167. - Ст.110785. - ISSN 00223697 (ISSN), DOI 10.1016/j.jpcs.2022.110785
Примечания : Cited References: 68. - This work is supported by the Russian Foundation for Basic Research, Project 18–29–19078. The authors would like to express their special thanks to Krasnoyarsk Regional Center of Research Equipment of Federal Research Center «Krasnoyarsk Science Center SB RAS» for providing the equipment to ensure the accomplishment of this project
Аннотация: Phenolic compounds are common environmental pollutants, which are used in many industries and contaminate water environment due to industrial wastewater discharge. Presently, there is an increasing demand for the development and improvement of inexpensive, easy-to-use analytical tools for in-situ detection of phenolic compounds. In this work, we investigate the effect of adsorption of Cu2+ and Fe2+ ions on the catalytic activity of a composite material based on alumina nanofibers (ANF) and detonation nanodiamonds (DND) in the co-oxidation of phenols with 4-aminoantipyrine in the presence of hydrogen peroxide. We have found more than two-fold increase of the catalytic activity for ANF + DND + Cu composite, while the activity of ANF + DND + Fe composite is found to decrease by several times in comparison with the original ANF + DND material. The results of FTIR analysis indicate that the adsorption of iron ions occurs with the formation of hydroxide surface groups and hydrogen bonds, which apparently block their catalytic activity in the Fenton redox cycle. The higher catalytic performance of AND + DND composite functionalized with copper ions makes it possible to detect two times lower concentrations of analytes (phenol and 4-chlorophenol) in comparison with the original composite. It is shown that the AND + DND + Cu composite provides a linear yield of the co-oxidation reaction product in a wide range of analyte concentrations (0.25–100 μM for phenol and 0.5–25 μM for 4-chlorophenol). Model experiments demonstrate the applicability of copper-functionalized composite as a reusable sensor for the determination of phenol in aqueous samples.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kudashev S. V., Kondrasenko A. A., Maiulev A. N., Babkin V. A., Belousova V. S., Andreev D. S., Zheltobryukhov V. F., Kuznetsova N. V.
Заглавие : Modification of polycaproamide composites based on 1H,1H,13H-rihydroperfluorotridecan-1-ol and montmorillonite
Место публикации : Fibre Chem. - 2022. - Vol. 53, Is. 5. - P.291-295. - ISSN 00150541 (ISSN), DOI 10.1007/s10692-022-10287-5
Примечания : Cited References: 24
Аннотация: Modification of polycaproamide by 1H,1H,13H-trihydroperfluorotridecan-1-ol immobilized on montmorillonite produced an F-containing polymer composite. The structure of the resulting composite was investigated using x-ray structure analysis and solid-state 19F NMR spectroscopy. The polymorphous composition of this heterochain polymer was shown to reorganize to enhance its thermal stability and diminish its flammability. Possible mechanisms for the stabilizing effect of the used modifier that were related to the involvement of organo-clay paramagnetic centers in the binding of macroradicals formed during thermal decomposition of macromolecular chains were discussed.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Tyurnev V. V., Khodenkov S. A.
Заглавие : The effective permittivity of an anisotropic composite of spheroidal particles in a dielectric matrix
Место публикации : Tech. Phys. Lett. - 2022. - Vol. 48, Is. 3. - P.110-114. - ISSN 10637850 (ISSN), DOI 10.1134/S1063785022040058
Примечания : Cited References: 10. - This study was carried out within the framework of state order FEFE-2020-0013 of the Ministry of Science and Higher Education of the Russian Federation
Аннотация: The concentration dependences of the effective permittivity have been obtained for an anisotropic composite consisting of a dielectric matrix filled with codirectional particles in the form of oblate or prolate ellipsoids of revolution (spheroids). The calculation has been made by solving numerically a system of coupled quadratic and integral equations obtained using the rigorous modification of the quasi-static Bruggeman theory. It is shown that the traditional simplified modification of the Bruggeman theory, which is widely used for calculating anisotropic composites, leads to errors of different signs for electromagnetic waves of the longitudinal and transverse polarizations relative to the spheroid axes. The dependences of the errors on the particle concentration are nonmonotonic and extrema observed in them can exceed 100%. The positions and values of the extrema depend strongly on the ellipticity of particles and the contrast of their permittivity with that of the matrix.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Morozov E. V., Voronin A. S., Kniga, S., V, Buznik V. M.
Заглавие : Nuclear magnetic resonance study of ice-based composite materials reinforced with nanodisperse aluminum oxide fibers
Коллективы : Institute of Chemistry and Chemical Technology (Siberian Branch, Russian Academy of Sciences) [0287-2021-0012]; Russian Science FoundationRussian Science Foundation (RSF) [18-1300392]
Место публикации : Inorg. Mater. Appl. Res. - 2022. - Vol. 13, Is. 1. - P.217-224. - ISSN 2075-1133, DOI 10.1134/S2075113322010270. - ISSN 2075-115X(eISSN)
Примечания : Cited References: 21. - This work was performed within the scope of state contract no. 0287-2021-0012 of the Institute of Chemistry and Chemical Technology (Siberian Branch, Russian Academy of Sciences) in the part of developing the MRI methods for studying composite materials; also the work was supported by the Russian Science Foundation (project no. 18-1300392) in the part of the study of the processes of water crystallization and ice melting in ice-based composite materials
Предметные рубрики: SELF-DIFFUSION
WATER
Аннотация: Pulsed-field gradient NMR spectroscopy and magnetic resonance imaging methods were used to investigate water suspensions of nanosized fibers of aluminum oxide and ice composite materials based on these fibers. Introduction of the nanofibers was shown to have no noticeable structural effect in the suspensions in the Al2O3 concentration range of 1-10 wt %. High content of the filler was found to change the morphology and texture of the ice matrix in the composites remarkably: it becomes more homogeneous and acquires a higher degree of continuity; the melting front does not visualize internal melting zones or integrity defects in the composite. At the same time, addition of the nanofibers to the ice composites weakly influences the quantitative dynamics of the heat transfer, which is manifested in close values of the propagation speeds of the freezing/melting front in the samples at similar temperatures.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mikhlin Y. L., Borisov R. V., Vorobyev S. A., Tomashevich Y. V., Romanchenko A. S., Likhatski M. N., Karacharov A. A., Bayukov O. A., Knyazev Yu. V., Velikanov D. A., Zharkov S. M., Krylov A. S., Krylova S. N., Nemtsev I. V.
Заглавие : Synthesis and characterization of nanoscale composite particles formed by 2D layers of Cu-Fe sulfide and Mg-based hydroxide
Место публикации : J. Mater. Chem. A. - 2022. - Vol. 10, Is. 17. - P.9621-9634. - ISSN 20507488 (ISSN), DOI 10.1039/d2ta00877g
Примечания : Cited References: 84. - This research was supported by the Russian Foundation for Basic Research, Krasnoyarsk Territory Administration and Krasnoyarsk Territory Science Foundation, project 20-43-242903. Facilities of the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS” were employed in the work
Аннотация: We introduce here a multifunctional material composed of alternating atomic sulfide sheets close to the composition of CuFeS2 and Mg-based hydroxide ones (valleriite), which are assembled due to their electric charges of opposite sign. Valleriite particles 50-200 nm in lateral size and 10-20 nm in thickness were synthesized via a simple hydrothermal pathway using various concentrations of precursors and dopants, and examined with XRD, TEM, EDS, X-ray photoelectron spectroscopy, reflection electron energy loss spectroscopy (REELS), Mossbauer, Raman and UV-vis-NIR spectroscopies, and magnetization, dynamic light scattering, and zeta potential measurements. The electronic, magnetic and optical characteristics are found to be critically dependent on the charge (electron density) at the narrow-gap sulfide layers containing Cu+ and Fe3+ cations, and can be tuned via the composition of the hydroxide part. Particularly, substitution of Mg2+ with Al3+ increases the negative charge of the hydroxide layers and reduces the content of Fe3+-OH centers (10-45% of total iron); the effects of Cr and Co dopants entering both layers are more complicated. Mossbauer doublets of paramagnetic Fe3+ detected at room temperature transform into several Zeeman sextets at 4.2 K; the hyperfine fields up to 500 kOe and complex magnetic behavior, but not pure paramagnetism or antiferromagnetism, were observed for valleriites with the higher positive charge of the sulfide sheets, probably due to the depopulation of the minority-spin 3d states of S-bonded Fe3+ ions. Aqueous colloids of valleriite show optical absorption at 500-750 nm, which, along with the peaks at the same energies in REELS, may arise due to quasi-static dielectric resonance involving the vacant Fe 3d band and being dependent on the composition of both layers too. These and other findings call attention to valleriites as a new rich family of 2D materials for a variety of potential applications.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Vazhenina I. G., Yaroslavtsev R. N., Chekanova L. A., Cheremiskina E., Mikhlin Y.
Заглавие : Magnetic composite coatings FeC and NiC synthesized with arabinogalactan
Место публикации : IEEE Magn. Lett. - 2022. - Vol. 13. - Ст.2503505. - ISSN 1949307X (ISSN), DOI 10.1109/LMAG.2022.3164631
Примечания : Cited References: 23. - This work was supported by Russian Foundation for Basic Research, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science under Project 20-42-240010. The authors thank the Center of Collective Use of the Federal Research Center, Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences for the provided equipment
Аннотация: In this work, we investigated the ferromagnetic resonance spectra of metal/carbon composite coatings. FeC and NiC coatings were synthesized by electroless deposition using polysaccharide arabinogalactan. An analysis of the angular dependences of the resonance field showed that the coatings consist of three magnetic phases separated by a nonmagnetic phase of carbon.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mikhlin Y. L., Likhatski M. N., Romanchenko A. S., Vorobyev S. A., Tomashevich Y. V., Fetisova O. Yu., Bayukov O. A., Knyazev Yu. V., Nemtsev I. V., Karasev S. V., Karacharov A. A., Borisov R. V.
Заглавие : Valleriite-containing ore from Kingash deposit (Siberia, Russia): Mossbauer and X-ray photoelectron spectroscopy characterization, thermal and interfacial properties
Место публикации : J. Sib. Fed. Univ. Chem. - 2022. - Vol. 15, Is. 3. - P.303-317. - ISSN 19982836 (ISSN), DOI 10.17516/1998-2836-0294; Журн. СФУ. Химия
Примечания : Cited References: 25. - This research was funded by the Russian Foundation for Basic Research, Krasnoyarsk Territory Science Foundation and Krasnoyarsk Territory Administration, grant number 20-43-242903. Facilities of the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center «Krasnoyarsk Science Center SB RAS» were employed in the work
Аннотация: Valleriite, (Cu,Fe)S2×n(Mg,Al,Fe)(OH)2, and related layered minerals are of interest due to their unusual two-dimensional structure, formation mechanisms, physical and chemical properties, and potential involvement into mineral processing and materials science applications. Here, we have studied Kingash Cu-Ni ore samples containing 10-25% of valleriite in association with serpentines (lizardite and chrysotile) and magnetite using scanning electron microscopy and electron microprobe analysis, Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis and zeta potential measurement. The data are compared with those for Al-doped valleriite synthesized via a hydrothermal route. It was found that the Kingash valleriite contains excessive iron relative to CuFeS2 stoichiometry, which mainly occurs, leaving aside magnetite, as Fe3+-OH species in hydroxide layers of valleriite and minor Fe centers in serpentines. Thermal dehydroxylation of hydroxide layers of valleriites occurs near 500oC in inert atmosphere; in air, sulfide sheets oxidize with an exothermal peak at 447oC, and sulfur oxides don't volatilize but react with hydroxide groups of valleriite rather than serpentines. Zeta potential measurements of coarse ore particles using the flow potential technique suggested that the surface of valleriite is negatively charged in a wide pH range while the positive values at low pHs for fine particles are inflicted by serpentine. The findings demonstrate close resemblance of the natural and synthetic Al-doped valleriites, and the key role of valleriite, despite its moderate content, for the interfacial characteristics of the valleriite-bearing ores.Валлериит, (Cu, Fe)S2×n(Mg, Al, Fe)(OH)2 и родственные ему слоистые минералы представляют интерес в связи с их необычной двумерной структурой, механизмами образования, физическими и химическими свойствами и возможностью применения в процессах переработки полезных ископаемых и материаловедения. В настоящей работе с помощью сканирующей электронной микроскопии и электронного микрозондового анализа, мессбауэровской спектроскопии, рентгеновской фотоэлектронной спектроскопии (РФЭС), термического анализа и измерения дзета-потенциала нами были изучены образцы медно-никелевых руд Кингашского месторождения, содержащие 10–25 % валлериита в ассоциации с серпентинами (лизардит и хризотил) и магнетитом. Было проведено сравнение полученных данных с результатами измерений легированного алюминием валлериита, синтезированного гидротермальным способом. Установлено, что валлериит Кингашского месторождения содержит избыточное железо по отношению к стехиометрии CuFeS2, которое представлено в основном, не считая магнетита, в виде центров Fe3+-OH, расположенных в гидроксидных слоях валлериита и небольшого числа примесей Fe в серпентинах. Термическое дигидроксилирование гидроксидных слоев валлериитов происходит около 500 °C в инертной атмосфере; на воздухе сульфидные слои окисляются с экзотермическим пиком при 447 °C, а оксиды серы не улетучиваются, а реагируют скорее с гидроксидными группами валлериита, чем с серпентинами. Измерения дзета-потенциала крупных частиц руды с использованием метода потенциала протекания показали, что поверхность валлериита отрицательно заряжена в широком диапазоне рН, в то время как положительные показатели при низких значениях рН для более мелких частиц обусловлены присутствием серпентина. Полученные данные демонстрируют близкое сходство природного и синтетического валлериитов, легированного алюминием, и его ключевую роль для межфазных характеристик валлериитсодержащих руд, даже при его умеренном содержании.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Федоров Л. Ю., Дрокин, Николай Александрович, Карпов И. В., Ушаков А. В.
Заглавие : Электрофизические характеристики полимерного композита на основе сверхвысокомолекулярного полиэтилена с наночастицами CuO
Место публикации : Журн. СФУ. Техн. и технол. - 2022. - Т. 15, № 7. - С. 802-811. - ISSN 1999494X (ISSN), DOI 10.17516/1999-494X-0437; J. Sib. Fed. Univ. Eng. Technol. - ISSN 23136057 (eISSN)
Примечания : Библиогр.: 19. - Исследование выполнено за счет гранта Российского научного фонда (проект № 20-19-00021)
Аннотация: Методом импедансной спектроскопии исследованы электрофизические свойства композитного материала на основе сверхвысокомолекулярного полиэтилена с ограниченной массовой концентрацией 0,5 мас.% оксида меди CuO в диапазоне частот от 102 до 108 Гц. Предполагается, что введение в состав полимера малых концентраций наночастиц способствует более равномерному их осаждению на поверхностях полимерных гранул. Это позволяет в процессе тестирования таких образцов выявить наиболее вероятные механизмы их поляризации и протекания электрического тока в относительно однородном ансамбле наночастиц в полимерной матрице. Установлено, что внедряемые в полимерную матрицу наночастицы незначительно влияют на процессы электрической поляризации, но приводят к появлению частотно-зависимой проводимости в широком диапазоне частот. Этот процесс сопровождается существенным возрастанием диэлектрических потерь. Электрофизические характеристики полученных композитов обсуждаются с учётом переноса электрических зарядов (ионов или электронов) как по внутренней, так и по поверхностной структуре наночастиц CuO.The electrophysical properties of a composite material based on ultrahigh molecular weight polyethylene with a limited mass concentration of 0.5 wt% copper oxide CuO in the frequency range from 102 to 108 Hz were studied by impedance spectroscopy. It is assumed that the introduction of low concentrations of nanoparticles into the polymer composition contributes to their more uniform deposition on the surfaces of polymer granules. This makes it possible to reveal the most probable mechanisms of their polarization and the flow of electric current in a relatively homogeneous ensemble of nanoparticles in a polymer matrix during testing of such samples. It has been established that nanoparticles introduced into the polymer matrix have little effect on the processes of electric polarization, but lead to the appearance of frequency-dependent conductivity in a wide frequency range. This process is accompanied by a significant increase in dielectric losses. The electrophysical characteristics of the resulting composites are discussed taking into account the transfer of electric charges (ions or electrons) both along the internal and surface structures of CuO nanoparticles.
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