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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Hu T., Ning L., Gao Y., Qiao J., Song E., Chen Z., Zhou Y., Wang J., Molokeev M. S., Ke X., Xia Z., Zhang Q.
Заглавие : Glass crystallization making red phosphor for high-power warm white lighting
Место публикации : Light Sci. Appl. - 2021. - Vol. 10, Is. 1. - Ст.56. - ISSN 20955545 (ISSN), DOI 10.1038/s41377-021-00498-6
Примечания : Cited References: 50. - The present work was supported by the National Natural Science Foundations of China (Grant Nos. 51972118, 51961145101, 51722202 and 11974022), the Guangzhou Science & Technology Project (202007020005), the Fundamental Research Funds for the Central Universities (D2190980), and the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01X137)
Аннотация: Rapid development of solid-state lighting technology requires new materials with highly efficient and stable luminescence, and especially relies on blue light pumped red phosphors for improved light quality. Herein, we discovered an unprecedented red-emitting Mg2Al4Si5O18:Eu2+ composite phosphor (λex = 450 nm, λem = 620 nm) via the crystallization of MgO–Al2O3–SiO2 aluminosilicate glass. Combined experimental measurement and first-principles calculations verify that Eu2+ dopants insert at the vacant channel of Mg2Al4Si5O18 crystal with six-fold coordination responsible for the peculiar red emission. Importantly, the resulting phosphor exhibits high internal/external quantum efficiency of 94.5/70.6%, and stable emission against thermal quenching, which reaches industry production. The maximum luminous flux and luminous efficiency of the constructed laser driven red emitting device reaches as high as 274 lm and 54 lm W−1, respectively. The combinations of extraordinary optical properties coupled with economically favorable and innovative preparation method indicate, that the Mg2Al4Si5O18:Eu2+ composite phosphor will provide a significant step towards the development of high-power solid-state lighting.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Коржнева, Ксения Евгеньевна, Исаенко Л. И., Елисеев, Александр Павлович, Молокеев, Максим Сергеевич
Заглавие : Экспериментальное исследование процессов кристаллизации K2Ba(NO3)4 из раствор-расплава
Место публикации : Фундамент. пробл. совр. материаловед. - 2018. - Т. 15, № 1. - С. 11-15. - ISSN 1811-1416, DOI 10.25712/ASTU.1811-1416.2018.01.001
Примечания : Библиогр.: 7. - Работа выполнена в рамках государственного задания, проект № 0330 - 2016 - 0008 и при поддержке Российского фонда фундаментальных исследований (грант № 18-32-00359).
Ключевые слова (''Своб.индексиров.''): рост из раствор-расплава--двойные соединения--нецентросимметричные кристаллы k2ba(no3)4--рентгенофазовый и термический анализы--оптическое пропускание--growth from solution-melt--double compounds--noncentrosymmetrical crystals k2ba(no3)4--x-ray diffraction and thermal analysis--optical transmittance
Аннотация: С развитием технологий неуклонно возрастает потребность в высокоэффективных функциональных материалах. Поэтому все более важной и актуальной становится задача разработки принципов и алгоритмов поиска этих материалов. В настоящее время системы двойных нитратов привлекают внимание исследователей тем, что в этой группе существуют двойные соединения с нецентросимметричной структурой, которые рассматриваются как перспективные нелинейные материалы для коротковолнового диапазона. В результате проведенных ранее исследований из водных растворов были получены кристаллы K2Ba(NO3)4. Было выявлено, что K2Ba(NO3)4 при температуре 197,3 оС разлагается на KNO3 и Ba(NO3)2. Из-за большого количества дефектов (дендриты, зарастание основными гранями роста) оптическое качество этих кристаллов оказалось невысоким. Что обусловило необходимость поиска новых методик выращивания, обеспечивающих получение качественных оптически прозрачных кристаллов. Поэтому нами исследовались процессы кристаллизации K2Ba(NO3)4 из раствор-расплава. Подобран растворитель состава LiNO3-CsNO3-KNO3 с температурой эвтектик ниже температуры разложения двойного соединения. Выращены прозрачные кристаллы K2Ba(NO3)4 размером до 0,7 мм, определена их структура, показано отсутствие у них центра симметрии. На данных кристаллах были сняты спектры оптического пропускания. Исследование двух спектров данного соединения выращенного разными методами показало, что кристаллы, полученные из водных растворов, прозрачен от 0,25 мкм до 2,2 мкм, при этом наблюдается пик поглощения с максимум 0,3 мкм. Кристаллы, выращенные методом из раствор-расплава, прозрачны от 0,3 мкм до 2,2 мкм. Ширина запрещенной зоны составляет около 5 эВ.With the development of technology, the need for highly efficient functional materials is steadily increasing. Therefore, the developing of principles and algorithms for these materials' search becomes more and more important and actual. Currently systems of double nitrates attract researchers attention due to the double compounds with a noncentrosymmetric structure which are considered as promising nonlinear materials for the short-wave range. As a result of previous studies K2Ba(NO3)4 crystals were obtained from aqueous solutions. It was found that K2Ba(NO3)4 decomposes on KNO3 and Ba(NO3)2 at the temperature of 197.3 oC. Due to the large amount of defects (dendrites, overgrowing by the main growth facets), the optical quality of these crystals was not high. This necessitated the search for new growth techniques that provide the production of high-quality optically transparent crystals. Therefore, we investigated the processes of crystallization of K2Ba(NO3)4 from a solution-melt. A solvent of the LiNO3-CsNO3-KNO3 composition with a eutectic temperature below the decomposition temperature of the double compound was chosen. Transparent crystals of K2Ba(NO3)4 up to 0.7 mm in size were grown, their structure was determined, and the absence of center of symmetry was shown. The optical transmission spectra were investigated on these crystals. The study of two spectra of this compound grown by different methods showed that crystals obtained from aqueous solutions are transparent from 0.25 μm to 2.2 μm, with an absorption peak with a maximum of 0.3 μm. Crystals grown by the solution-melt method are transparent from 0.3 μm to 2.2 μm. The width of the band gap is about 5 eV.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Гаврилюк, Анатолий Петрович, Исаев, Иван Леонидович, Карпов, Сергей Васильевич, Герасимов, Валерий Сергеевич
Заглавие : Электронный туннельный эффект и особенности кристаллизации наноразмерных золей металлов
Место публикации : Инженерная физика. - Москва: Общество с ограниченной ответственностью Издательство Научтехлитиздат, 2009. - № 2. - С. 51-53. - ISSN 2072-9995
Предметные рубрики:
Ключевые слова (''Своб.индексиров.''): nano particles--наночастицы--tunnel effect--bimodal bands--туннельный эффект--бимодальный ансамбль
Аннотация: Исследуются закономерности самоорганизации бимодальных ансамблей наночастиц в кристаллические структуры в лиозолях металлов (на примере органозолей золота) методом броуновской динамики. Показана возможность селективной коагуляции разно-размерных частиц вследствие асимметрии встречных туннельных электронных потоков межу частицами разных размеров и их взаимного разнополярного заряжения; исследуется кинетика этого процесса.Explored conformity to the law organizations of bimodal bands of nano particles in crystalline structures in liozole metals (for example of organozole gold) by the method of brownian dynamics. Possibility of selective coagulation of particles of different-sizes is shown because of asymmetry of meetings tunnel electronic streams boundary path by the particles of different sizes and their mutual different arctic loading; explored kinetics of this process.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zaitsev A. I., Zamkov A. V., Molokeev M. S., Cherepakhin A. V., Koroleva N. S.
Заглавие : Phase formation upon crystallization of SrO center dot 2B(2)O(3) glasses
Место публикации : Crystallogr. Rep. - NEW YORK: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 56, Is. 1. - С. 44-51. - JAN. - ISSN 1063-7745, DOI 10.1134/S1063774511010263
Примечания : Cited Reference Count: 21
Предметные рубрики: STRONTIUM TETRABORATE
LUMINESCENCE
SRB4O7
GROWTH
Ключевые слова (''Своб.индексиров.''): crystalline form--crystalline formation--crystalline phasis--glass surfaces--phase formations--thermal analysis--thermal stability--crystalline materials--crystallization--glass--thermoanalysis--thermodynamic stability--metastable phases
Аннотация: The crystallization of SrO center dot 2B(2)O(3) glasses has been studied. Four different crystalline formations were found to form simultaneously and independently on the glass surface: stable alpha-SrB4O7 crystals and metastable crystalline forms (beta-SrB4O7, Sr4B14O25, and spherulites (presumably, mixtures of crystalline phases)). The ranges of thermal stability of the newly formed metastable phases have been established using thermal analysis.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H., Wang L., Cho Y., Hirosaki N., Molokeev M. S., Xia Z., Huang Z., Xie R.-J.
Заглавие : New Y2BaAl4SiO12:Ce3+ yellow microcrystal-glass powder phosphor with high thermal emission stability
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 41. - P.9872-9878. - ISSN 20507534 (ISSN), DOI 10.1039/c6tc03422e
Примечания : Cited References: 32. - This study was partially supported by the National Natural Science Foundation of China (Grant No. 51272259, 51572232 and 51561135015). R. X. was also partially supported by the JSPS KAKENHI (No. 15K06448). M. M. and Z. X. were also partially supported by the Russian Foundation for Basic Research (No. 15-52-53080). H. J. thanks the China Scholarship Council (CSC) for scholarship support.
Ключевые слова (''Своб.индексиров.''): aluminum--crystal structure--crystallization--glass--laser applications--light emission--microcrystals--phosphors--precipitation (chemical)--quenching--silicon--silicon oxides--single crystals--structural design--crystalline nature--crystallization behavior--emission intensity--microcrystal glass--morphology structures--phase formation behavior--structure analysis--temperature increase--cerium
Аннотация: To decrease the rare earth element usage and synthesis cost of Y3Al5O12:Ce phosphor, the Y2BaAl4SiO12 compound is developed as a new host for Ce3+ employing the solid solution design strategy. The design uses polyhedron substitution where YO8/AlO4 are partially replaced by BaO8/SiO4, respectively. Structure analysis of Y2BaAl4SiO12 proves that it successfully preserves the garnet structure, crystallizing in the cubic Iad space group with a = b = c = 12.00680(5) Å. Barium (Ba) atoms occupy the Y site and silicon (Si) atoms occupy the Al site in the AlO4 tetrahedrons. An expanded study on Y2MAl4SiO12 (M = Ba, Ca, Mg, Sr) series shows a cation size (of M)-dependent phase formation behavior. The lattice stability can be related with the M type in the M–Si pair and substitution level of M–Si for Y–Al. Doping Ce3+ into Y2BaAl4SiO12 yields bright yellow photoluminescence peaking at around 537 nm upon excitation by 460 nm light. The emission intensity is quite stable against thermal quenching whereas the peak wavelength shows a slight red-shift as the ambient temperature increases. The crystallization behavior of Y2BaAl4SiO12 is suggested as melt-assisted precipitation/growth based on cathodoluminescence analysis. The highly crystalline nature of the microcrystals explains the stable emission against thermal quenching. This study may provide an inspiring insight into preparing phosphor with new morphology-structure of “microcrystal-glass powder phosphor”, which distinguishes it from conventional “ceramic powder phosphor” or “single-crystal phosphor”.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : NESTEROV A. I., Ovchinnikov S. G.
Заглавие : ACOUSTIC-WAVE AMPLIFICATION IN FAST CRYSTALLIZATION
Место публикации : Fiz. Tverd. Tela: MEZHDUNARODNAYA KNIGA, 1988. - Vol. 30, Is. 1. - P184-186. - ISSN 0367-3294
Примечания : Cited References: 14
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang, Xuejiao, Molokeev M. S., Zhu, Q.i., Li, Ji-Guang
Заглавие : Controlled hydrothermal crystallization of anhydrous Ln2(OH)4SO4 (Ln = Eu-Lu, Y) as a new family of layered rare earth metal hydroxides
Место публикации : Chem. - A Eur. J. - 2017. - Vol. 23, Is. 63. - P.16034-16043. - ISSN 0947-6539, DOI 10.1002/chem.201703282. - ISSN 1521-3765(eISSN)
Примечания : Cited References:54. - This work is supported in part by the National Natural Science Foundation of China (Grants Nos. 51702020, and 51672039), Doctoral Research Fund of Liaoning Province (Grant No. 20170520103) and the Russian Foundation for Basic Research (17-52-53031). X.W. acknowledges the financial support from the China Scholarship Council for her overseas Ph.D. study (Contract No. 201406080035).
Предметные рубрики: ANION-EXCHANGE MATERIALS
BOND-VALENCE PARAMETERS
X-RAY-DIFFRACTION
Ключевые слова (''Своб.индексиров.''): hydrothermal synthesis--layered compounds--luminescence--oxide sulfates--rare earths
Аннотация: Anhydrous hydroxide sulfates Ln2(OH)4SO4 (Ln=Eu–Lu, Y) were hydrothermally synthesized as a new family of layered rare earth metal hydroxides (LRHs). They crystallize in the monoclinic system (space group C2/m) with structures built up by alternate stacking of interlayer SO42− and the two-dimensional host layer composed of tricapped [LnO9] trigonal prisms along the a axis. In distinct contrast to the recently discovered hydrated LRHs Ln2(OH)4SO4⋅2 H2O, which only exist for Ln=La–Dy, the host layers of the anhydrous phase are linked together by sharing edges instead of an O node of the SO42− tetrahedron. Rietveld refinement showed that the cell dimension tends to decrease for smaller Ln3+, while the axis angle (β=98.78–100.31°) behaves oppositely. Comparative thermogravimetric/differential thermal analysis in air revealed that the dehydroxylation and desulfurization temperatures become gradually higher and lower, respectively, for smaller Ln3+, and thus the temperature range of Ln2O2SO4 existence is narrowed. The newly discovered Ln2(OH)4SO4, together with their hydrated counterparts, allow for the first time green synthesis of Ln2O2SO4 with water as the only exhaust for the full spectrum of lanthanides. Calcining Ln2(OH)4SO4 in H2 yielded phase-pure Ln2O2S for Eu and Gd and a mixture of Ln2O2S and Ln2O3 for the other Ln. The effects of the lanthanide contraction were clearly revealed, and photoluminescence was found for the anhydrous LRHs of Eu and Tb.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang X., Li J. -G., Molokeev M. S., Wang X., Liu W., Zhu Q., Tanaka H., Suzuta K., Kim B. -N., Sakka Y.
Заглавие : Hydrothermal crystallization of a Ln2(OH)4SO4·nH2O layered compound for a wide range of Ln (Ln = La-Dy), thermolysis, and facile transformation into oxysulfate and oxysulfide phosphors
Место публикации : RSC Adv.: Royal Society of Chemistry, 2017. - Vol. 7, Is. 22. - P.13331-13339. - ISSN 20462069 (ISSN), DOI 10.1039/c7ra00645d
Примечания : Cited References: 54. - This work was partly supported by the National Natural Science Foundation of China (Grants No. 51672039, 51172038, and 51302032), the Fundamental Research Fund for the Central Universities (Grant No. N140204002), the Grants-in-Aid for Scientific Research (KAKENHI No. 26420686), and the Russian Foundation for Basic Research (15-52-53080). Xuejiao Wang acknowledges the financial support received from the China Scholarship Council for her overseas Ph. D. study at the National Institute of Materials Science (Contract No. 201406080035).
Ключевые слова (''Своб.индексиров.''): dysprosium--hydrothermal synthesis--light emission--phase structure--phosphors--rare earth elements--acceleration voltages--chemical compositions--electron beam irradiation--hydrothermal conditions--hydrothermal crystallization--lanthanide contraction--photoluminescence properties--structure refinements--dysprosium compounds
Аннотация: The synthesis of a layered Ln2(OH)4SO4·nH2O material (Ln-241) with a smaller lanthanide ion (Dy3+) was successfully achieved through the optimization of the hydrothermal conditions, and the effect of lanthanide contraction on the chemical composition, phase structure, and crystallite/particle morphology of the products was investigated and discussed. Structure refinement showed that the lattice parameters (a, b, and c), cell volume, and axis angle across the series (Ln = La-Dy) monotonously decrease as the size of Ln3+ decreases. Comparative TG/DTA analysis in air indicated that the dehydroxylation temperature of Ln-241 tends to increase, whereas the dehydration and desulfurization temperatures decrease as the size of Ln3+ decreases, thus narrowing the stable temperature range for Ln2O2SO4. Taking advantage of the fact that Ln-241 has exactly the same Ln/S molar ratio as Ln2O2SO4 and Ln2O2S, the latter two groups of important compounds (excluding Ce) were facilely transformed from the former via the removal of water by calcination. The photoluminescence properties of Eu3+ and Tb3+, in terms of excitation, emission, fluorescence decay, quantum yield, and emission color, were investigated and compared for the two hosts Gd2O2S and Gd2O2SO4, and the (Gd0.99Tb0.01)2O2S phosphor was shown to be stable under electron beam irradiation in the studied range and exhibited an increasingly higher emission brightness as the acceleration voltage (up to 7 kV) or beam current (up to 50 μA) increased.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Vereshchagin S.N., Vereshchagina T.A., Solovyov L.A., Shishkina N.N., Vasilieva N.G., Anshits A.G.
Заглавие : Solid-phase transformation of Cs+- and Sr2+-bearing zeolite sorbents derived from cenospheres to mineral-like forms
Место публикации : Materials Research Society Symposium Proceedings. - 2009. - Vol. 1193: 32nd Symposium on Scientific Basis for Nuclear Waste Management (24 May 2009 through 29 May 2009, St. Petersburg, ) Conference code: 79940. - С. 87-94. - ISBN 02729172 (ISSN); 9781605111667 (ISBN)
Ключевые слова (''Своб.индексиров.''): apparent activation energy--cenospheres--crystalline minerals--crystalline phasis--crystallization temperature--higher temperatures--long-term disposal--multi phase systems--pollucites--principal components--solid-phase transformation--temperature range--thermal treatment--thermochemical transformations--transformation temperatures--xrd analysis--activation energy--atmospheric pressure--cesium--crystalline materials--crystallization--fly ash--metallic glass--radioactive waste disposal--radioactive wastes--silicate minerals--sodium--sorbents--sorption--strontium--synthesis (chemical)--waste management--atmospheric temperature
Аннотация: The paper describes the studies of the transformation of Cs+- and Sr2+-containing zeolite sorbents synthesized from fly ash cenospheres to crystalline mineral composition, suitable for the long-term disposal. Series of Cs+- and Sr2+-exchanged NaP1-containing sorbents were subjected to the thermochemical transformation in the temperature range 40-1100°C at atmospheric pressure in air and the progress of reaction was monitored by DSC and XRD analysis. It was shown that initial sodium zeolite undergoes two-step transformation at 736-785°C and 892-982°C forming nepheline as the principle product, with the conversion temperatures being dependant on the heating rate. The thermal treatment of Cs+-bearing zeolite sorbent led to formation of a complex multiphase system, the principal components of which were nepheline and pollucite. Increasing cesium content in the samples led to a monotonous shift of crystallization peak to the higher temperature range (1005-1006°C). A more complicated behavior was observed for Sr2+-containing samples, for which the crystallization temperature tends to increase (compared with NaP1) at lower Sr contents, but it starts decreasing parallel to the Sr2+ content at Sr2+ loadings 10 mg/g. The principal crystalline phases in Sr-NaP1 sample conversion were nepheline and Sr2+- containing feldspar, the quantity of which increased parallel to the increase of strontium content in zeolite. Apparent activation energies of thermochemical transformations were calculated and possible approaches to reduce transformation temperature are discussed and experimentally illustrated. © 2009 Materials Research Society.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bezmaternykh L. N., Temerov V. L., Gudim I. A., Stolbovaya N.A.
Заглавие : Crystallization of trigonal (Tb,Er)(Fe,Ga)(3)(BO3)(4) phases with hantite structure in bismuth trimolybdate-based fluxes
Место публикации : Crystallogr. Rep. - 2005. - Vol. 50. - P.S97-S99. - ISSN 1063-7745, DOI 10.1134/1.2133981
Примечания : Cited Reference Count: 8
Предметные рубрики:
Аннотация: The stability regions of the trigonal (Tb,Er)(Fe,Ga)(3)(BO3)(4) phases are established in (Bi2Mo3O12)-based fluxes. The specific features of heterogeneous nucleation and the subsequent phase transformations during transition to the equilibrium are studied in the vicinity of the boundaries. The temperature modes of single crystal growth on seeds are suggested with due regard for the "nonequilibrium effect." (C) 2005 Pleiades Publishing, Inc.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Uspenskaya, Mayya V., Kiselev, Evgeniy G., Sukovatyi, Aleksey G., Zhila, Natalia O., Vasiliev A. D., Shishatskaya, Ekaterina I.
Заглавие : Effect of monomers of 3-hydroxyhexanoate on properties of copolymers poly(3-hydroxybutyrate-co 3-hydroxyhexanoate)
Место публикации : Polymers. - 2023. - Vol. 15, Is. 13. - Ст.2890. - ISSN 20734360 (eISSN), DOI 10.3390/polym15132890
Примечания : Cited References: 99. - The study was funded by the Russian Science Foundation (project No 23-64-10007)
Аннотация: The properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) copolymers with different ratios of monomers synthesized by the wild-type strain Cupriavidus necator B-10646 on sugars, and an industrial sample from Kaneka synthesized by the recombinant strain C. necator NSDG-ΔfadB1 on soybean oil, were studied in a comparative aspect and in relation to poly(3-hydroxybutyrate) P(3HB). The copolymer samples, regardless of the synthesis conditions or the ratio of monomers, had reduced values of crystallinity degree (50–60%) and weight average molecular weight (415–520 kDa), and increased values of polydispersity (2.8–4.3) compared to P(3HB) (70–76%, 720 kDa, and 2.2). The industrial sample had differences in its thermal behavior, including a lower glass transition temperature (−2.4 °C), two peaks in its crystallization and melting regions, a lower melting point (Tmelt) (112/141 °C), and a more pronounced gap between Tmelt and the temperature of thermal degradation (Tdegr). The process, shape, and size of the spherulites formed during the isothermal crystallization of P(3HB) and P(3HB-co-3HHx) were generally similar, but differed in the maximum growth rate of the spherulites during exothermic crystallization, which was 3.5–3.7 μm/min for P(3HB), and 0.06–1.25 for the P(3HB-co-3HHx) samples. The results from studying the thermal properties and the crystallization mechanism of P(3HB-co-3HHx) copolymers are important for improving the technologies for processing polymer products from melts.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zharkov S. M., Yumashev V. V., Moiseenko E. T., Altunin R. R., Solovyov L. A., Volochaev M. N., Zeer G. M., Nikolaeva N. S., Belousov O. V.
Заглавие : Thermokinetic study of aluminum-induced crystallization of a-Si: The effect of Al layer thickness
Колич.характеристики :24 с
Место публикации : Nanomaterials. - 2023. - Vol. 13, Is. 22. - Ст.2925. - ISSN 20794991 (eISSN), DOI 10.3390/nano13222925
Примечания : Cited References: 70. - This work was supported by the Russian Science Foundation under grant #22-13-00313
Аннотация: The effect of the aluminum layer on the kinetics and mechanism of aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) in (Al/a-Si)n multilayered films was studied using a complex of in situ methods (simultaneous thermal analysis, transmission electron microscopy, electron diffraction, and four-point probe resistance measurement) and ex situ methods (X-ray diffraction and optical microscopy). An increase in the thickness of the aluminum layer from 10 to 80 nm was found to result in a decrease in the value of the apparent activation energy Ea of silicon crystallization from 137 to 117 kJ/mol (as estimated by the Kissinger method) as well as an increase in the crystallization heat from 12.3 to 16.0 kJ/(mol Si). The detailed kinetic analysis showed that the change in the thickness of an individual Al layer could lead to a qualitative change in the mechanism of aluminum-induced silicon crystallization: with the thickness of Al ≤ 20 nm. The process followed two parallel routes described by the n-th order reaction equation with autocatalysis (Cn-X) and the Avrami–Erofeev equation (An): with an increase in the thickness of Al ≥ 40 nm, the process occurred in two consecutive steps. The first one can be described by the n-th order reaction equation with autocatalysis (Cn-X), and the second one can be described by the n-th order reaction equation (Fn). The change in the mechanism of amorphous silicon crystallization was assumed to be due to the influence of the degree of Al defects at the initial state on the kinetics of the crystallization process.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Zhila, Natalia O., Kiselev, Evgeniy G., Sukovatyi, Aleksey G., Lukyanenko A. V., Shishatskaya, Ekaterina I.
Заглавие : Biodegradable polyhydroxyalkanoates with a different set of valerate monomers: Chemical structure and physicochemical properties
Колич.характеристики :21 с
Место публикации : Int. J. Mol. Sci. - 2023. - Vol. 24, Is. 18. - Ст.14082. - ISSN 16616596 (ISSN), DOI 10.3390/ijms241814082. - ISSN 14220067 (eISSN)
Примечания : Cited References: 99. - The study was funded by the Russian Science Foundation (project no. 23-64-10007)
Аннотация: The properties, features of thermal behavior and crystallization of copolymers containing various types of valerate monomers were studied depending on the set and ratio of monomers. We synthesized and studied the properties of three-component copolymers containing unusual monomers 4-hydroxyvalerate (4HV) and 3-hydroxy-4-methylvalerate (3H4MV), in addition to the usual 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) monomers. The results showed that P(3HB-co-3HV-co-4HV) and P(3HB-co-3HV-co-3H4MV) terpolymers tended to increase thermal stability, especially for methylated samples, including an increase in the gap between melting point (Tmelt) and thermal degradation temperature (Tdegr), an increase in the melting point and glass transition temperature, as well as a lower degree of crystallinity (40–46%) compared with P(3HB-co-3HV) (58–66%). The copolymer crystallization kinetics depended on the set and ratio of monomers. For terpolymers during exothermic crystallization, higher rates of spherulite formation (Gmax) were registered, reaching, depending on the ratio of monomers, 1.6–2.0 µm/min, which was several times higher than the Gmax index (0.52 µm/min) for the P(3HB-co-3HV) copolymer. The revealed differences in the thermal properties and crystallization kinetics of terpolymers indicate that they are promising polymers for processing into high quality products from melts.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sinyakova E. F., Vasilyeva I. G., Oreshonkov A. S., Goryainov S. V., Karmanov N. S.
Заглавие : Formation of noble metal phases (Pt, Pd, Rh, Ru, Ir, Au, Ag) in the process of fractional crystallization of the CuFeS2 melt
Место публикации : Minerals. - 2022. - Vol. 12, Is. 9. - Ст.1136. - ISSN 2075163X (ISSN), DOI 10.3390/min12091136
Примечания : Cited References: 61. - This work was supported by the Russian Federation state assignment of Sobolev Institute of Geology and Mineralogy of SB RAS, Nikolaev Institute of Inorganic Chemistry SB RAS, and Kirensky Institute of Physics of Federal Research Center KSC SB RAS. The grant number is projects II.1.64. and 40330-2016-0001
Аннотация: The quasi-equilibrium directional crystallization of the melt composition (at. %): Cu 24.998, Fe 25.001, S 49.983, with Ag 0.002, Pd 0.003, Ru 0.004, Rh 0.006, and Au, Pt, Ir (each as 0.001) was carried out. The crystallized cylindrical ingot consisted of two primary zones and three secondary zones with different chemical and phase compositions. The compositions of the primary zones corresponded to high-temperature intermediate solid solution (zone I) and liquid enriched in sulfur (zone II). The compositions of the secondary zones corresponded to low-temperature intermediate solid solution and chalcopyrite (zone Ia), the same intermediate solid solution with chalcopyrite and bornite (zone Ib), and again with bornite, chalcocite, and idaite (zone II). We plotted the distribution curves of Fe, Cu, and S along the ingot, calculated the distribution coefficients of the components during directional crystallization, and clearly showed that, from the initial stoichiometric composition CuFeS2, the intermediate solid solution enriched in Fe and depleted in S is crystallized. Based on the data of directional crystallization and thermal analysis, a cross section was constructed in the intermediate solid solution-sulfide melt region of the Cu-Fe-S system. With solubility in the solid Cu-Fe sulfides lying below detection limit of scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDS), noble elements occurred as individual phases of a size more often <10 µm. They were identified as Ag, RuS2, PdS, Au* (an Au based alloy), (Rh, Ir, Ru)3S8, (Rh, Ir)3S8, Rh3S8, and (Cu, Fe)~2(Pt, Rh)1S~5 phases by electron microprobe. Based on ab initio calculations of crystal structure, electronic band structure, and lattice dynamics of idealized laurite RuS2 phase and the idealized Ir3S8, Rh3S8, and Ru3S8 phases, the interpretation of Raman spectrum of the cation-mixed (Ru, Rh, Ir)S2 sulfide was presented for the first time.
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15.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Molokeev M. S., Bovina A. F., Shabanova K. A., Kokh D., Velikanov D. A., Eremin E. V., Bezmaternykh L. N., Moshkina E. M.
Заглавие : Peculiarities and comparison of Cu2MBO5 (M = Fe, Mn, Cr) ludwigites crystallization in Bi2O3-MoO3-Na2O-B2O3 multicomponent fluxes
Коллективы : Российская академия наук, Физико-технический институт им. Е.К. Завойского ФИЦ Казанского научного центра РАН, Казанский (Приволжский) федеральный университет, Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium
Место публикации : VIII Euro-Asian symposium "Trends in magnetism" (EASTMAG-2022): Book of abstracts/ program com. S. G. Ovchinnikov [et al.]. - 2022. - Vol. 2, Sect. G: Frustrated and disordered magnetism. - Ст.G.P8. - P.25-26. - ISBN 978-5-94469-051-7
Примечания : Cited References: 6. - The study was supported by the Russian Science Foundation (grant No. 22-12-20019)
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kveglis L. I., Zhigalov V. S.
Заглавие : Directional crystallization and self-assembling initiated by mechanical shock or electron beam in nanocrystalline Co-C and Fe-C films
Место публикации : Surface Science: Elsevier Science Publishing Company, Inc., 2007. - Т. 601, № 13. - С. 2873-2875. - ISSN 0039-6028, DOI 10.1016/j.susc.2006.12.044
ГРНТИ : 31.15
РИНЦ,
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17.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Voronov V. N., Nikolayeva T. V.
Заглавие : Crystallization and studies of A+B3+F4 compounds
Коллективы : "Advanced inorganic fluorides", International Siberian workshop
Место публикации : Advanced inorganic fluorides: the Third International Siberian workshop Intersibfluorine - 2008, September 01-06, 2008, Vladivostok, Russia : proceedings of ISIF-2008. - Vladivostok, 2008. - p.200-203. - ISBN 978-5-98128-036-8
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Edelman I., Kliava J.
Заглавие : Oxide glasses with magnetic nanoparticles: transparent magnets (Faraday rotation and electron magnetic resonance studies)
Коллективы : RFBR-CNRS [07-02-92174]
Разночтения заглавия :авие SCOPUS: Oxide glasses with magnetic nanoparticles: Transparent magnets (Faraday rotation and electron magnetic resonance studies)
Место публикации : Phys. Status Solidi B. - 2009. - Vol. 246, Is. 10. - P.2216-2231. - ISSN 0370-1972, DOI 10.1002/pssb.200945169
Примечания : Cited References: 87. - This work is supported in part by RFBR-CNRS joint project, grant No 07-02-92174. We are grateful to E. Petrakovskaja and O. Ivanova for measuring and discussing, respectively, the EMR spectra in thermally treated samples and the FR spectral and magnetic field dependences.
Предметные рубрики: SPIN-HAMILTONIAN PARAMETERS
SINGLE-DOMAIN PARTICLES
SUPERPARAMAGNETIC RESONANCE
CRYSTALLIZATION BEHAVIOR
FERRIMAGNETIC RESONANCE
PARAMAGNETIC-RESONANCE
TEMPERATURE-DEPENDENCE
COMPUTER-SIMULATIONS
FINE PARTICLES
BORATE GLASSES
Аннотация: In the first part of this paper we outline the state of the art in the field of magnetic nanoparticles in oxide glasses. We describe the theoretical background of two complementary techniques used for the studies of the state of paramagnetic ions, clusters and magnetic particles in a diamagnetic matrix, viz., magnetooptical Faraday rotation (FR) and electron magnetic resonance (EMIR) and we overview previous results obtained with these techniques for several glass systems. In the second part, we highlight the case of potassium-alumina-borate glasses - a glassy system where doping with paramagnetic oxides results in formation of magnetic particles at very low contents of paramagnetic additions: Fe(2)O(3) and MnO. In the special case when the ratio of the iron and manganese oxides in the charge is 3/2, magnetic nanoparticles with characteristics close to those of manganese ferrite are formed already at the first stage of the glass preparation. After thermal treatment all glasses show FR and EMR spectra attesting to the presence of superparamagnetic nanoparticles, characterized by relatively broad size and shape distributions. The formation of magnetic nanoparticles confers to these glasses magnetic and magnetooptical properties typical of magnetically ordered substances. At the same time, the glasses remain transparent in a part of the visible and near infrared spectral range and display a high FR value. Such properties make them particularly interesting for use as new media for various magneto-optical devices. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang X., Li J. -G., Molokeev M. S., Zhu Q., Li X., Sun X.
Заглавие : Layered hydroxyl sulfate: Controlled crystallization, structure analysis, and green derivation of multi-color luminescent (La,RE)2O2SO4 and (La,RE)2O2S phosphors (RE = Pr, Sm, Eu, Tb, and Dy)
Место публикации : Chem. Eng. J.: Elsevier, 2016. - Vol. 302. - P.577-586. - ISSN 13858947 (ISSN), DOI 10.1016/j.cej.2016.05.089
Примечания : Cited References: 50. - This work is supported in part by the National Natural Science Foundation of China (Grants Nos. 51172038, 51302032, and U1302272), the Fundamental Research Fund for the Central Universities (Grant No. N140204002), Grants-in-Aid for Scientific Research (KAKENHI No. 26420686), and the Russian Foundation for Basic Research (15-52-53080). X.J. Wang acknowledges financial support from the China Scholarship Council for her overseas Ph.D. study (Contract No. 201406080035) and the assistance of Q. Q. Zhu (University of Science and Technology of China) for his help with calcination.
Предметные рубрики: PHOTOLUMINESCENCE PROPERTIES
OXYSULFATE/OXYSULFIDE SYSTEMS
CRYSTAL-STRUCTURE
OXYGEN-STORAGE
Ln
NANOCOMPOSITES
EMISSION
CAPACITY
FAMILY
FABRICATION
Ключевые слова (''Своб.индексиров.''): sulfate type layered rare earth hydroxide--luminescence--oxysulfate--oxysulfide
Аннотация: The two important groups of Ln2O2SO4 and Ln2O2S compounds are traditionally synthesized with the involvements of environmentally harmful sulfur-containing reagents. We developed in this work a unique green approach for their synthesis, using Ln2(OH)4SO4·2H2O layered hydroxyl sulfate as the precursor (Ln-241 phase). Phase selective crystallization of La-241 under both atmospheric pressure and hydrothermal conditions was firstly optimized, followed by transformation into La2O2S and La2O2SO4 by controlled calcination. Rietveld structure refinement was performed for La-241, La(OH)SO4, La2O2SO4, and La2O2S, and the crystal structure and cell parameters of La-241 were originally reported. The photoluminescence performances of several important activators (Pr3+, Sm3+, Eu3+, Tb3+, and Dy3+) in the two hosts, in terms of excitation, emission, quantum yield, and color coordinates of emission, were thoroughly investigated, and multi-color luminescence including bright red, green, orange red, and yellow was obtained under ultraviolet excitation. Detailed investigations of Tb3+ photoluminescence revealed that the lack of 5D3 emission in La2O2S and the gradual quenching of 5D3 blue emission at a higher Tb3+ content (hence decreasing I488/I545 ratio and changing color coordinates) in La2O2SO4 were suggested to be due to thermal activation of the 5D3 electrons into the conduction band and cross relaxation between adjacent Tb3+, respectively. The synthesis approach developed in this work for La2O2SO4 and La2O2S, with water vapor as the only exhaust gas, is environmentally benign and holds great potential in the facile synthesis of analogous compounds of other lanthanides. © 2016 Elsevier B.V.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Frolov K. V., Lyubutin I. S., Smirnova E. S., Alekseeva O. A., Verin I. A., Artemov V. V., Kharlamova S. A., Bezmaternykh L. N., Gudim, I. A.
Заглавие : Low-temperature structural and magnetic phase transitions in multiferroic GdFe3(BO3)4
Коллективы : Russian Foundation for Basic Research [14-02-00483a, 13-02-12442]; Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools [NSh-1130.2014.5, NSh-924.2014.2]; Russian Ministry of Education and Science [RFMEFI62114X0005]
Место публикации : J. Alloys Compd.: Elsevier Science, 2016. - Vol. 671. - P.545-551. - ISSN 0925-8388, DOI 10.1016/j.jallcom.2016.02.083. - ISSN 1873-4669(eISSN)
Примечания : Cited References:36. - We thank Dr. A.P. Dudka for help in the low temperature XRD measurements. This study was supported in part by the Russian Foundation for Basic Research (projects # 14-02-00483a and 13-02-12442), and the Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools (grant # NSh-1130.2014.5 and # NSh-924.2014.2). This work was performed using the equipment of the Shared Research Center IC RAS and was supported by the Russian Ministry of Education and Science (project RFMEFI62114X0005).
Предметные рубрики: IRON BORATE GDFE3(BO3)4
BIFEO3 THIN-FILMS
MAGNETOELASTIC PROPERTIES
RM3(BO3)4 CRYSTALS
TRIGONAL GDFE3(BO3)4
ENHANCED POLARIZATION
HIGH-PRESSURES
CRYSTALLIZATION
BEHAVIOR
GROWTH
Ключевые слова (''Своб.индексиров.''): multiferroics--rare earth compounds--x-ray diffraction--mossbauer--spectroscopy--crystal structure--spin dynamics
Аннотация: X-ray analysis revealed that at temperature decreasing from room temperature to Tstr = 155 K the crystal unit cell GdFe3(BO3)4 is reduced only along the c axis (at 0.01 Å), while the a and b axes are unchanged within the error limits. The volume of the crystal decreases uniformly in the direction of all three axes at 155–80 K. At 80–30 K the crystal volume is decreased only by reduction of the parameters a and b, while the parameter c increases conversely. In the paramagnetic region Mössbauer spectra do not distinguish between the two structural positions of iron ions Fe1 and Fe2, appearing at T < Tstr. Below the temperature of the magnetic phase transition at TN = 38.0(1) K the Mössbauer data indicate quasi-one-dimensional magnetic ordering of iron moments in the sublattice Fe2 and a two-dimensional one in the iron sublattice Fe1. The dynamics of spin reorientation in sublattices Fe1 and Fe2 is studied in detail.Рентгеновский анализ показал, что при уменьшении температуры от комнатной до Tstr = 155 K изменение параметра элементарной ячейки кристалла GdFe3(BO3)4 происходит лишь вдоль оси с (при 0,01 Å), в то время как а и b оси остаются неизменными в пределах погрешности измерений. Объем кристалла уменьшается равномерно в направлении всех трех осей при 155-80 K. При 80-30 K объем кристалла уменьшается только уменьшением параметров a и b, в то время как параметр с наоборот увеличивается. В парамагнитной области Мессбауэровские спектры не различают двух структурных позиций ионов железа Fe1 и Fe2, появляющиеся при Т˂Tstr. Ниже температуры магнитного фазового перехода при TN = 38,0(1) К Мёссбауэрские данные указывают на квази-одномерный магнитное упорядочение моментов железа в подрешетке Fe2 и двумерное в железной подрешетке Fe1. Динамика спиновой переориентации в подрешетках Fe1 и Fe2 подробно изучается.
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