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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S., Golovneva I. I., Glushchenko G. A.
Заглавие : Crystal structure of enrofloxacinium tetrabromidodichloridostannate(IV) monohydrate
Место публикации : J. Struct. Chem.: SPRINGER, 2013. - Vol. 54, Is. 2. - P.377-382. - ISSN 0022-4766, DOI 10.1134/S0022476613020157
Примечания : Cited References: 17. - The work was supported by the grant of the President of the Russian Federation for the support of leading scientific schools of the Russian Federation (NSh-4828.2012.2) and the Federal Targeted Program "Scientific and Scientific Pedagogical Personnel of Innovative Russia, 2009-2013" (State contracts Nos. 02.740.11.0269 and 02.740.11.0629).
Предметные рубрики: COMPLEX
Ключевые слова (''Своб.индексиров.''): crystal structure--enrofloxacinium cation--tetrabromidodichloridostannate(iv) anion--hydrogen bonds
Аннотация: A new compound EnrH(3)[SnBr3.46Cl2.54]center dot H2O, where EnrH (3) (2+) is the enrofloxacinium cation (C19H24FN3O (3) (2+) ), is synthesized and its crystal and molecular structure is determined. Crystallographic data for enrofloxacinium tetrabromidodichloridostannate(IV) monohydrate are as follows: a = 17.1262(19) , b = 10.3435(11) , c = 17.2582(19) , beta = 119.203(1)A degrees, V = 2640.5(4) (3), space group P2(1)/c, Z = 4. Hydrogen bonds form a branched three-dimensional network linking EnrH (3) (2+) , [SnBr3.46Cl2.54](2-), and water molecules. The structure is also stabilized by the pi-pi interaction of EnrH (3) (2+) aromatic rings.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zamkova N. G., Zhandun V. S., Zinenko V. I.
Заглавие : First-principles calculations of ferroelectric properties in AA`BB`O6 double perovskites with different types of cation ordering
Место публикации : Phys. status solidi B. - 2013. - Vol. 250, Is. 9. - P.1888-1897. - ISSN 0370-1972, DOI 10.1002/pssb.201349084
Ключевые слова (''Своб.индексиров.''): density functional theory--double perovskites--ferroelectrics--polarization
Аннотация: First-principles calculations of lattice dynamics and polarization properties have been performed for double perovskite ABiBNbO6 (A - alkali metal Na, Rb, and B - trivalent metal Sc, Lu). Three possible types of A- and B-site cation ordering are studied: layer and columnar ordering of A-site cations with rocksalt ordering of B-site cations, and layer ordering of both cations. The ground state of all compounds is polar with a large value of polarization for all types of cation ordering. For some compounds we obtain spontaneous polarization of 0.7-1.0Cm-2 that is twice the BaTiO3 value. For RbBiScNbO6 the lowest-energy state has layer ordering of both A- and B-site cations, which is rare for compounds with double-perovskite structure.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Li G., Lin C. C., Chen W.-T., Molokeev M. S., Atuchin V. V., Chiang C.-Y., Zhou W., Wang C.-W., Li W.-H., Sheu H.-S., Chan T.-S., Ma C., Liu R.-S.
Заглавие : Photoluminescence tuning via cation substitution in oxonitridosilicate phosphors: DFT calculations, different site occupations, and luminescence mechanisms
Место публикации : Chem. Mater.: American Chemical Society, 2014. - Vol. 26, Is. 9. - P.2991-3001. - ISSN 0897-4756, DOI 10.1021/cm500844v. - ISSN 1520-5002
Примечания : Cited References: 62. - The authors would like to thank the Ministry of Science and Technology of Taiwan (Contract No. MOST 101-2113-M-002-014-MY3), the National Synchrotron Radiation Research Center, Taiwan, the National Natural Science Foundation of China (Grant No. NSFC 21301162), and the Fundamental Research Funds for the Central Universities (Grant No. CUG 130402) for financially supporting this research. Victor V. Atuchin gratefully acknowledges the Ministry of Education and Science of the Russian Federation for the financial support.
Предметные рубрики: LIGHT-EMITTING-DIODES
HIGH-TEMPERATURE SYNTHESIS
LED CONVERSION PHOSPHORS
CRYSTAL X-RAY
WHITE-LIGHT
ORDERED DISTRIBUTION
GREEN PHOSPHOR
LAYERED OXONITRIDOSILICATE
REAL STRUCTURE
AB-INITIO
Аннотация: Tuning and optimizing luminescent properties of oxonitridosilicates phosphors are important for white light-emitting diode (WLED) applications. To improve the color rendering index, correlated color temperature and thermal stability of layer-structured MSi2O2N2:Eu (M = Sr, Ba) phosphors, cation substitutions have been used to adjust their luminescent properties. However, the underlying mechanisms are still unclear. In this research, a series of (Sr1-xBax)Si2O2N2:Eu (0 ≤ x ≤ 1) compounds were prepared by solid-state reaction, after which systematic emission variations were investigated. The crystal structures of (Sr1-xBax)Si2O2N2:Eu (0 ≤ x ≤ 1) are nominally divided into three sections, namely, Phase 1 (0 ≤ x ≤ 0.65), Phase 2 (0.65 x 0.80), and Phase 3 (0.80 ≤ x ≤ 1) based on the X-ray diffraction measurements. These experimental results are further confirmed by optimizing the crystal structure data with first-principle calculations. Continuous luminescence adjustments from green to yellow are observed in Phase 1 with gradual replacement of Sr2+ with Ba2+, and the abnormal redshift is clarified through extended X-ray absorption fine structure analysis. Sr(Eu)-O/N bond length shrinkage in local structure causes the redshift emission, and the corresponding luminescence mechanism is proposed. Controllable luminescence in Phase 2 (from blue to white) and Phase 3 (from cyan to yellowish green) are observed. Based on the high-resolution transmission electron microscopy and selected area electron diffraction analysis, the two kinds of luminescence tuning are attributed to phase segregation. This study serves as a guide in developing oxonitride luminescent materials with controllable optical properties based on variations in local coordination environments through cation substitutions.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji H. P., Huang Z. H., Xia, Zhiguo, Molokeev M. S., Atuchin V. V., Huang S. F.
Заглавие : Cation substitution dependent bimodal photoluminescence in whitlockite structural Ca3-xSrx(PO4)2:Eu2+ (0 ≤ x ≤ 2) solid solution phosphors
Место публикации : Inorg. Chem.: American Chemical Society, 2014. - Vol. 53, Is. 20. - P.11119-11124. - ISSN 0020-1669, DOI 10.1021/ic501679f. - ISSN 1520-510X
Примечания : Cited References: 37. - This work was supported by the National Natural Science Foundations of China (Grant Nos. 51032007, 51002146, 51272242), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130022110006), the Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), and Beijing Youth Excellent Talent Program (YETP0635). V.V.A. acknowledges the Ministry of Education and Science of the Russian Federation for financial support.
Предметные рубрики: LIGHT-EMITTING-DIODES
EFFICIENT ENERGY-TRANSFER
EMISSION-TUNABLE PHOSPHOR
EXCITED WHITE LEDS
CRYSTAL-STRUCTURE
LUMINESCENCE PROPERTIES
Mn2+ PHOSPHOR
COLOR TONE
PHASE
Eu2+
Аннотация: Cation substitution dependent tunable bimodal photoluminescence behavior was observed in the Ca3-xSrx(PO4)2:Eu2+ (0 ≤ x ≤ 2) solid solution phosphors. The Rietveld refinements verified the phase purity and whitlockite type crystal structure of the solid solutions. The tunable photoluminescence evolution was studied as a function of strontium content, over the composition range 0.1 ≤ x ≤ 2. In addition to the emission band peak at 416 nm in Ca3(PO4)2:Eu2+, the substitution of Ca2+ by Sr2+ induced the emerging broad-band peak at 493-532 nm. A dramatic red shift of the emission peak located in the green-yellow region was observed on an increase of x in the samples with 0.75 ≤ x ≤ 2.00. The two emission bands could be related to the EuOn-Ca9 and EuOn-Ca9-xSrx emitting blocks, respectively. The values for the two kinds of emitting blocks in the solid solutions can be fitted well with the observed intensity evolution of the two emission peaks.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang Z. Y., Xia, Zhiguo, Molokeev M. S., Atuchin V. V., Liu Q. L.
Заглавие : Blue-shift of Eu2+ emission in (Ba,Sr)3Lu(PO4)3:Eu2+ eulytite solid-solution phosphors resulting from release of neighbouring-cation-induced stress
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2014. - Vol. 43, Is. 44. - P.16800-16804. - ISSN 1477-9226, DOI 10.1039/c4dt02319f. - ISSN 1477-9234
Примечания : Cited References: 16. - The present work was supported by the National Natural Science Foundations of China (grant no. 51002146, no. 51272242), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in the University of the Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635) and the Funds of the State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University (KF201306). V.V.A. is partly supported by the Ministry of Education and Science of the Russian Federation.
Предметные рубрики: TUNABLE COLOR TONE
EXCITED WHITE LEDS
CRYSTAL-STRUCTURE
TEMPERATURE
IONS
Аннотация: A series of iso-structural eulytite-type (Ba,Sr)(3)Lu(PO4)(3):Eu2+ solid-solution phosphors with different Sr/Ba ratios were synthesized by a solid-state reaction. Crystal structures of (Ba,Sr)(3)Lu(PO4)(3):Eu2+ were resolved by the Rietveld method, which shows an eulytite-type cubic Bi-4(SiO4)(3) structure with cations disordered in a single C-3 site while the oxygen atoms were distributed over two partially occupied sites. The emission peaks of Ba(3-x)SrxLu(PO4)(3):Eu2+ (0
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6.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Ryabinkina L. I., Romanova O. B., Kisilev N. I.
Заглавие : Magnetotranport properties of cation-substituted sulphides VXMn1-XS
Коллективы : Moscow International Symposium on Magnetism, Московский государственный университет им. М.В. Ломоносова
Место публикации : Moscow Int. Symp. on Magnet. (MISM-2014): Book of abstracts. - 2014. - Ст.1PO-K-11. - P.544. - ISBN 978-5-91978-025-0
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Beznosikov B. V., Aleksandrov K. S.
Заглавие : Prediction of pra-phases of layered perovskite-like structures with cation vacancies
Место публикации : J. Struct. Chem. - 2002. - Vol. 43, Is. 1. - P.172-175. - ISSN 0022-4766, DOI 10.1023/A:1016098521933
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ji, Haipeng, Huang, Zhaohui, Xia, Zhiguo, Molokeev M. S., Atuchin V. V., Fang, Minghao, Liu, Yangai
Заглавие : Discovery of new solid solution phosphors via cation substitution-dependent phase transition in M-3(PO4)2:Eu2+ (M =Ca/Sr/Ba) quasi-binary sets
Место публикации : J. Phys. Chem. C: American Chemical Society, 2015. - Vol. 119, Is. 4. - P.2038-2045. - ISSN 1932-7447, DOI 10.1021/jp509743r
Примечания : Cited References:48. - This work was supported by the National Natural Science Foundations ofChina (Grant Nos. 51032007, 51002146, and 51272242), the Research Fundfor the Doctoral Program of Higher Education of China (Grant No.20130022110006), the Natural Science Foundations of Beijing (2132050),the Program for New Century Excellent Talents in University of Ministryof Education of China (NCET-12-0950), the Beijing Nova Program(Z131103000413047), and Beijing Youth Excellent Talent Program(YETP0635). V.V.A. acknowledges the Ministry of Education and Science ofthe Russian Federation for financial support.
Предметные рубрики: LIGHT-EMITTING-DIODES
LUMINESCENCE PROPERTIES
ENERGY-TRANSFER
Аннотация: The cation substitution-dependent phase transition was used as a strategy to discover new solid solution phosphors and to efficiently tune the luminescence property of divalent europium (Eu2+) in the M3(PO4)2:Eu2+ (M = Ca/Sr/Ba) quasi-binary sets. Several new phosphors including the greenish-white SrCa2(PO4)2:Eu2+, the yellow Sr2Ca(PO4)2:Eu2+, and the cyan Ba2Ca(PO4)2:Eu2+ were reported, and the drastic red shift of the emission toward the phase transition point was discussed. Different behavior of luminescence evolution in response to structural variation was verified among the three M3(PO4)2:Eu2+ joins. Sr3(PO4)2 and Ba3(PO4)2 form a continuous isostructural solid solution set in which Eu2+ exhibits a similar symmetric narrow-band blue emission centered at 416 nm, whereas Sr2+ substituting Ca2+ in Ca3(PO4)2 induces a composition-dependent phase transition and the peaking emission gets red shifted to 527 nm approaching the phase transition point. In the Ca3?xBax(PO4)2:Eu2+ set, the validity of crystallochemical design of phosphor between the phase transition boundary was further verified. This cation substitution strategy may assist in developing new phosphors with controllably tuned optical properties based on the phase transition.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Romanova O. B., Khar'kov A. M., Galyas A. I.
Заглавие : Investigation of the transport properties of cation-substituted solid solutions Yb x Mn1 − x S
Коллективы : Russian Foundation for Basic Research [12-02-00125_a, 15-02-01445_a]
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2015. - Vol. 57, Is. 5. - P.886-890. - ISSN 1063, DOI 10.1134/S1063783415050029. - ISSN 10906460(eISSN)
Примечания : Cited References:18. - This study was supported by the Russian Foundation for Basic Research (project nos. 12-02-00125_a and 15-02-01445_a).
Предметные рубрики: ELECTRICAL-PROPERTIES
TRANSITION
GD
Аннотация: The electrical properties and thermopower of solid solutions Yb x Mn1 − x S with substitution concentrations 0 x ≤ 0.2 have been studied in the temperature range of 77–1050 K. It has been found that the electrical conductivity has a semiconducting character, and the thermopower changes its sign from positive to negative as the substitution concentration in Yb x Mn1 − x S increases. It has been established that the activation energy decreases with increasing ytterbium concentration. The model of impurity donor 4f states satisfactorily agrees with the data on the electrical resistivity and the thermopower.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Романова, Оксана Борисовна, Харьков, Анатолий Михайлович, Ситников, Максим Николаевич, Кретинин В. В.
Заглавие : Переход металл-диэлектрик в катион-замещенных соединениях ReхMn1-xS (Re = Gd, Sm, Ho)
Место публикации : Вестник СибГАУ. - Красноярск: СибГАУ, 2015. - Т. 16, № 2. - С. 478-484. - ISSN 1816-9724 (Шифр В22/2015/16/2)
Примечания : Библиогр.: 38. - Работа выполнена при финансовой поддержке РФФИ № 15-42-04099 р_Cибирь_а и государственного задания № 114090470016.
Ключевые слова (''Своб.индексиров.''): сульфиды редкоземельных элементов--проводимость--переход металл-диэлектрик--термоэдс--sulfides of rare-earth elements--conductivity--transition metal-insulator--thermoelectric power
Аннотация: Представлены результаты исследования транспортных свойств катион-замещенных сульфидов RexMn1-xS (Re = Gd, Sm, Ho) с ГЦК-решеткой типа NaCl в области температур 77-1200 К. С увеличением степени катионного замещения в этих соединениях RexMn1-xS (Re = Gd, Sm, Ho) изменяется тип проводимости от полупроводникового до металлического при критической концентрации Х С. Концентрационный переход металл-диэлектрик в системе Gd XMn 1-XS сопровождается уменьшением величины удельного электросопротивления на 12 порядков и коэффициента термоЭДС (α) на два порядка. Катионное замещение в твердых растворах GdxMn1-xS приводит к смене дырочного типа проводимости (α 0), свойственного моносульфиду марганца, на электронный (α 0). Уменьшение величины α с увеличением содержания гадолиния в решетке MnS указывает на то, что Gd действует как донорная примесь. Для Sm 0,2Mn 0,8S обнаружен резкий максимум сопротивления при Т This paper presents the results of a study of the transport properties of cation-substituted sulfides Re XMn 1-XS (Re = = Gd, Sm, Ho) with FCC NaCl type in the temperature range 77-1200 K. With increasing degree of cation substitution in these compounds Re XMn 1- ХS (Re = Gd, Sm, Ho) the conductivity type changes from the semiconductor to the «metal» at the critical concentration X C. The concentration of metal-insulator transition in the system Gd XMn 1-XS is accompanied by a decreasing in the electrical resistivity of value on 12 orders and Seebeck coefficient (α) is on two orders. The cation-substitution in the solid solutions Gd XMn 1-XS leads to p-type conductivity (α 0), as comprising to electronic (α 0) for manganese monosulfide. Decrease of α with increasing gadolinium concentration in the MnS lattice indicates that the Gd acts as a donor impurity. For Sm 0,2Mn0,8S a maximum resistance at T
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11.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Romanova O. B., Aplesnin S. S., Galyas A. I., Yanushkevich K. I., Sokolov V. V.
Заглавие : Cation-substituted TmXMn1-XS solid solutions with special magnetic and electrical properties
Коллективы : International Conference on Magnetism
Место публикации : 20th Int. Conf. on Magnetism (ICM-2015): book of abstracts. - 2015. - P.241
Предметные рубрики: Semiconductor spintronics
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sofronova S. N., Bezmaternykh L. N., Eremin E. V., Nazarenko I. I., Volkov N. V., Kartashev A. V., Moshkina E. M.
Заглавие : The superexchange interactions and magnetic ordering in low-dimentional ludwigite Ni5GeB2O10
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 401. - P.217-222. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2015.10.024
Примечания : Cited References: 23. - This study was supported by Russian Foundation for Basic Research (RFFI Siberia No. 15-42-04186). We thank S. Popkov, G. Yurkin for help on the magnetic measurements and M.S. Molokeev for help on the x-ray diffraction
Предметные рубрики: DIELECTRICS
EXCHANGE
CATION
Ключевые слова (''Своб.индексиров.''): ludwigites--magnetic order--heat capacity--exchange interactions--ferrimagnetic
Аннотация: The ludwigite Ni5Ge(BO5)2 belongs to a family of oxyborates which have low-dimensional subunits in the form of three-leg ladders unit structure. This material was studied by magnetic and thermodynamic measurements. Ni5Ge(BO5)2 does not show full long-range magnetic order, but one goes into a partial ordering or spin-glass state at 87 K. The superexchange interactions were calculated in the framework of a simple indirect coupling model. Different models of magnetic structure of Ni5Ge(BO5)2 and its unique magnetic behaviour was discussed. © 2015 Elsevier B.V.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vasiliev A. D., Golovnev N. N.
Заглавие : Crystal structure of two ionic sparfloxacin compounds
Место публикации : J. Struct. Chem.: MAIK Nauka-Interperiodica / Springer, 2015. - Vol. 56, Is. 5. - P.907-911. - ISSN 00224766 (ISSN), DOI 10.1134/S0022476615050121
Примечания : Cited References: 20
Предметные рубрики: ANTIBACTERIAL AGENTS
QUINOLONE
MONOHYDRATE
COMPLEXES
Ключевые слова (''Своб.индексиров.''): crystal structure--hydrogen bonds--sparfloxacindi-ium cation--zinc and cadmium tetrahalide anions--π-π interaction
Аннотация: The structure of two new ionic compounds of sparfloxacin (C19H22F2N4O3, SfH), SfH3[ZnCl4]•1.5H2O (I) and SfH3[CdBr4]•H2O (II), is determined. Crystallographic data are as follows: for I a = 14.505(3) Å, b = 12.615(3) Å, c = 29.118(7) Å, V = 5254(4)Å3, space group Pbca, Z = 8; for II a = 13.2822(5) Å, b = 10.2564(4) Å, c = 21.3250(8) Å, β = 100.7248(4)°, V = 2854.3(3) Å3, space group P21/ n, Z = 4. The structures of the compounds are stabilized by intra- and intermolecular hydrogen bonds and the structure of I is additionally stabilized by the π-π interaction between the SfH 3 2+ ions. © 2015 Pleiades Publishing, Ltd.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Удод, Любовь Викторовна, Ситников, Максим Николаевич
Заглавие : Влияние катионного замещения на полиморфные переходы в пирасаннате висмута Bi2Sn2O7
Место публикации : Вестник СибГАУ. - Красноярск: СибГАУ, 2015. - Т. 16, № 4. - С. 975-982. - ISSN 1816-9724
Примечания : Библиогр.: 53. - Работа выполнена при финансовой поддержке Российского фонда фундаментальных исследований, грант № 15-42-04099 р_сибирь_а, и государственного задания № 114090470016
Ключевые слова (''Своб.индексиров.''): полиморфные переходы--диэлектрическая проницаемость--электросопротивление--катионное замещение--дифференциальная сканирующая калориметрия--polymorphic transitions--dielectric permeability--cation substitution--electrical resistivity--differential scanning calorimetry
Аннотация: Рассмотрена разработка технологии новых сенсорных материалов, необходимых для газочувствительных приборов, применяемых в ракетостроении. Целью данной работы является изучение влияния допирования разновалентными катионами на кристаллографическую структуру, диэлектрические и электрические свойства пирохлорного соединения Bi 2Sn 2O 7, обладающего селективной избирательностью к газам. Методом твердофазного синтеза впервые синтезированы соединения Bi2(Sn1-xMex)2O7, где Me = Mn, Cr, x = 0, 0,05, находящиеся сразу в двух полиморфных модификациях - орторомбической и кубической. В твердых растворах Bi2(Sn0,95Cr0,05)2O 7 методом сканирующей калориметрии обнаружено два новых структурных перехода, по сравнению со станнатом висмута Bi2Sn2O7. Ионы Mn 4+ сместили фазовые границы полиморфных переходов в сторону меньших температур, а фазовый α→β-переход около 370 К, характерный для Bi2(Sn1-xCrx)2O7, где x = 0, 0,05, подавили почти полностью. Полиморфный переход при Т = 543 К для Bi 2(Sn0,95Mn0,05) 2O 7 протекает с выделением тепла, в отличие от Bi2(Sn1-xCrx)2O7, где x = 0, 0,05. Исследована взаимосвязь структурных, электрических и диэлектрических свойств. Установлены аномалии в температурной зависимости электросопротивления и диэлектрической проницаемости (мнимой и реальной частями) как в области низких температур, так и при высоких температурах. Эти особенности объясняются в рамках модели мартенситных фазовых переходов. Методом сканирующей калориметрии найдены температуры структурных фазовых переходов, которые коррелируют с аномалиями электросопротивления в интервале температур 300 T 1000 К для Bi2(Sn1-xCrx)2O7, x The goal of this work is to develop a new technology of sensor materials required for gas sensing devices used in missile. The aim of this work is to study the effect of doping cations with different valency on the crystallographic structure, dielectric and electrical properties of pyrochlore compound Bi2Sn2O7 with selectivity to gases. Polycrystalline compounds Bi2(Sn1-xMex)2O7, where Me = Mn, Cr, x = 0, 0.05 have been synthesized by conventional solid-state reaction. According to the X-ray powder diffraction research, our sample consists of two polymorphs phases: cubic and rhombic. Two new structural transition are found in Bi2(Sn0.95Cr0.05)2O7 solid solutions by scanning calorimetry, as compared to bismuth pyrostannate Bi2Sn2O7. Ions Mn 4+ leads to shift of phase boundary of polymorphic transitions towards lower temperatures, and the phase α→β-transition at about 370 K, which is characteristic for Bi2(Sn1-xCrx)2O7, where x = 0, 0.05 is suppressed. The polymorphic transition at T = 543 K for Bi2(Sn0.95Mn0.05)2O7 occurs with calorification, in contrast to Bi2(Sn1-xCrx)2 7, where x = 0, 0.05. The relationship between structural, electrical and dielectric properties is investigated. Anomalies in the temperature dependence of electrical resistivity and dielectric permeability (real and imaginary part) as in the low region temperatures as in the high region temperature are found. These features are explained within a model of martensitic phase transitions. The temperature of the structural phase transitions correlates with temperature of maximum of the electrical resistivity in the temperature range 300 T 1000 K for Bi2(Sn1-xCrx)2O7, x
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Xia Z., Liu G., Wen J., Mei Z., Balasubramanian M., Molokeev M. S., Peng L., Gu L., Miller D. J., Liu Q., Poeppelmeier K. R.
Заглавие : Tuning of photoluminescence by cation nanosegregation in the (CaMg)x(NaSc)1-xSi2O6 solid solution
Место публикации : J. Am. Chem. Soc.: American Chemical Society, 2016. - Vol. 138, Is. 4. - P.1158-1161. - ISSN 00027863 (ISSN), DOI 10.1021/jacs.5b12788
Примечания : Cited References: 23. - Work performed by Z.X. and Q.L. was supported by the National Natural Science Foundation of China (51272242 and 51572023), the Program for New Century Excellent Talents in the University of the Ministry of Education of China (NCET-12-0950), and the Beijing Nova Program (Z131103000413047). Work performed by G.L., J.W., Z.M., M.B., and D.J.M. at Argonne National Laboratory was supported by the Office of Basic Energy Sciences of the U.S. Department of Energy (DOE) through Grant DE-AC02-06CH11357 for research on heavy elements chemistry and materials sciences. TEM was accomplished in part at the Center for Nanoscale Materials, a DOE Office of Science User Facility under Contract DE-AC02-06CH11357. Sector 20 operations at APS are supported by DOE and the Canadian Light Source, with additional support from the University of Washington. G.L. acknowledges travel support from the CAS/SAFEA International Partnership Program for Creative Research Teams. K.R.P. gratefully acknowledges support from the National Science Foundation (DMR-1307698).
Предметные рубрики: SPINODAL DECOMPOSITION
ENERGY-TRANSFER
EXSOLUTION
CLINOPYROXEN
NANOCRYSTALS
SEGREGATION
MECHANISMS
PYROXENESS
JERVISITE
PHOSPHORS
Аннотация: Controlled photoluminescence tuning is important for the optimization and modification of phosphor materials. Herein we report an isostructural solid solution of (CaMg)x(NaSc)1-xSi2O6 (0 < x < 1) in which cation nanosegregation leads to the presence of two dilute Eu2+ centers. The distinct nanodomains of isostructural (CaMg)Si2O6 and (NaSc)Si2O6 contain a proportional number of Eu2+ ions with unique, independent spectroscopic signatures. Density functional theory calculations provided a theoretical understanding of the nanosegregation and indicated that the homogeneous solid solution is energetically unstable. It is shown that nanosegregation allows predictive control of color rendering and therefore provides a new method of phosphor development. © 2016 American Chemical Society.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Li O. A., Lin C. -R., Chen H. -Y., Hsu, Hua-Shu, Shih K. -Y., Edelman I. S., Wu K. -W., Tseng Y. -T., Ovchinnikov S. G., Lee J. -S.
Заглавие : Size dependent magnetic and magneto-optical properties of Ni0.2Zn0.8Fe2O4 nanoparticles
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 408. - P.206-212. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2016.02.062
Примечания : Cited References: 51. - This work is supported by the Ministry of Science and Technology of Taiwan (MOST 103-2811-M-153 -001 and MOST 102-2112-M-153 -002 -MY3), and by the Russian Foundation for Basic Researches, grant No 14-02-01211.
Предметные рубрики: Zinc ferrite
Cation distribution
Sol-gel
Ni
ZnFe2O4
Spinel
Fe3O4
Particles
Spectra
State
Ключевые слова (''Своб.индексиров.''): nickel zinc ferrite--nanoparticles--magnetic properties--mcd
Аннотация: Ni0.2Zn0.8Fe2O4 spinel nanoparticles have been synthesized by combustion method. Average particles size varies from 15.5 to 50.0 nm depending on annealing temperature. Correlations between particles size and magnetic and magneto-optical properties are investigated. Magnetization dependences on temperature and external magnetic field correspond to the sum of paramagnetic and superparamagnetic response. Critical size of single-domain transition is found to be 15.9 nm. Magnetic circular dichroism (MCD) studies of nickel zinc spinel are presented here for the first time. The features in magnetic circular dichroism spectrum are assigned to the one-ion d-d transitions in Fe3+ and Ni2+ ions, as well to the intersublattice and intervalence charge transfer transitions. The MCD spectrum rearrangement was revealed with the change of the nanoparticles size. © 2016 Elsevier B.V. All rights reserved.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S.
Заглавие : Crystal structure of thallium(I) 2-thiobarbiturate
Коллективы : Siberian Federal University within Government task of the Ministry of Education and Science of the Russian Federation [3049]
Место публикации : Russ. J. Inorg. Chem.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 61, Is. 4. - P.442-446. - ISSN 0036-0236, DOI 10.1134/S0036023616040100. - ISSN 1531-8613(eISSN)
Примечания : Cited References:25. - This work was performed in the Siberian Federal University within the Government task of the Ministry of Education and Science of the Russian Federation for 2014-2016 (project no. 3049).
Предметные рубрики: Thiobarbituric acid-derivatives
Cation
Аннотация: The crystal and molecular structures of thallium(I) thiobarbiturate C4H3N2O2STl (C4H4N2O2S is 2-thiobarbituric acid, Н2ТВА) have been determined. Crystallographic data for Tl(НТВА) are a = 11.2414(7) Å, b = 3.8444(3) Å, с = 14.8381(9) Å, β = 99.452(2)°, V = 649.00(7) Å3, space group P2/с, Z = 4. Each of the two independent thallium ions is bonded to four oxygen and two sulfur atoms to form a distorted tetrahedron. N‒H…O and C‒H…S hydrogen bonds form a branched three-dimensional network. The structure is also stabilized by π‒π interaction between heterocyclic НТВА- ions. The IR spectra of Tl(НТВА) agree with X-ray powder diffraction data. The compound is also stable below 280°C, and Tl2SO4 is one of the thermolysis products in an oxidative medium in the region of 500‒650°C.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhu L., Huang Z., Molokeev M. S., Min X., Liu Y., Fang M., Wu X.
Заглавие : Influence of cation substitution on the crystal structure and luminescent properties in apatite structural Ba4.97- xSrx(PO4)3Cl:0.03Eu2+ phosphors
Место публикации : Chem. Phys. Lett.: Elsevier, 2016. - Vol. 658. - P.248-253. - ISSN 00092614 (ISSN), DOI 10.1016/j.cplett.2016.06.061
Примечания : Cited References: 23. - This present work was supported by the National Natural Science Foundations of China (Grant Nos. 51472222 and 51372232), the Fundamental Research Funds for the Central Universities (Grant No. 2652015310), and the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130022110006).
Предметные рубрики: PHOTOLUMINESCENCE
ENERGY
Ce3+
Sr
UV
Ключевые слова (''Своб.индексиров.''): substitution--apatite--ba4.97- xsrx(po4)3cl:0.03eu2+--luminescence
Аннотация: A series of apatite-type phosphors Ba4.97- xSrx(PO4)3Cl:Eu2+(x = 0, 0.5, 1.0, 1.5, 2.0) were synthesized by the high temperature solid-state reaction method, and its luminescence properties were investigated in detail. It can be found that a red shift of the emission peak wavelength emerged from 439 to 462 nm with the continuous introduction of Sr2+ into the crystal lattice which has been simulated by a crystal-field model. The red shift is explained by the distortion in the crystal structure through X-ray diffraction and the Rietveld refinement analysis. According to a recently raised structural model, Eu2+ ions are surrounded by O atoms, PO4 tetrahedrons and Ba/Sr ions. After introducing Sr2+ into the lattice, the interatomic distance between Ba/Sr atoms and Eu2+ was expected to become shorter, resulting in a distortion of the inner EuOn polyhedrons. Then the crystal field strength surrounding Eu2+ was increased, finally resulting in the red shift. © 2016 Published by Elsevier B.V.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vasil'ev A. D., Golovnev N. N., Lesnikov M. K.
Заглавие : Crystal structure of [Bi(N-ethylthiourea)4(ClO4)2]ClO4
Место публикации : Russ. J. Inorg. Chem.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 61, Is. 6. - P.704-707. - ISSN 00360236 (ISSN), DOI 10.1134/S003602361606022X
Примечания : Cited References: 21
Ключевые слова (''Своб.индексиров.''): hydrogen bonds--bismuth complexes--mutual repulsion--octahedral cation--thiocarbonyl--crystal structure
Аннотация: The structure of the bismuth(III) complex with N-ethylthiourea (Ettu) has been determined for the first time. We found that the crystal structure of [Bi(Ettu)4(ClO4)2]ClO4 is built of distorted octahedral cations [Bi(Ettu–S)4(ClO4)2]ClO4]+ and anions ClO4 -. The deviation of one of the two independent Ettu molecules from the plane structure is explained by the mutual repulsion of the ligands and the formation features of hydrogen bonds. The C2H5(Ettu) group is in the cis position relative to the thiocarbonyl group. © 2016, Pleiades Publishing, Ltd.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wei Y., Lin C. C., Quan Z., Molokeev M. S., Atuchin V. V., Chan T. -S., Liang Y., Lin J., Li G.
Заглавие : Structural evolution induced preferential occupancy of designated cation sites by Eu2+ in M5(Si3O9)2 (M = Sr, Ba, Y, Mn) phosphors
Место публикации : RSC Adv.: Royal Society of Chemistry, 2016. - Vol. 6, Is. 62. - P.57261-57265. - ISSN 20462069 (ISSN), DOI 10.1039/c6ra11681g
Примечания : Cited References: 28. - This project is financially supported by the National Natural Science Foundation of China (Grants No. NSFC 21301162, 21571162, 60977013, 91433110, U1301242, 21221061), the National College Students' Innovative Training Program (Nos. 201510491109, 201610491067, 201610491070), and the Ministry of Science and Technology of Taiwan (No. MOST 104-2917-1-564-060). Zewei Quan acknowledges the funding support (FRG-SUSTC1501A-17) from South University of Science and Technology of China.
Предметные рубрики: LUMINESCENCE PROPERTIES
RED LUMINESCENCE
UP-CONVERSION
WHITE LEDS
PHOTOLUMINESCENCE
NANOPHOSPHORS
YELLOW
WLEDS
Аннотация: In this paper, we present new insight into a changing Eu2+ crystallographic site preference in Eu-doped M5(Si3O9)2 (M = Sr, Ba, Y, Mn), which is related to the structural variation induced by M cation substitutions. The effect of the local structural geometry on the luminescence properties of Eu2+ is revealed. By substitution of Ba2+ for Sr2+, the lattice expansion is restricted to specific cation sites, resulting in the abrupt blue shifted emission of Eu2+ ions. The abnormal blue shift on replacing Sr2+ with Mn2+ is attributed to the preferential 6-fold coordination for Mn2+ that moves the Eu2+ ions to other sites. The results elucidate the mechanisms of emission band adjustment by local site coordination change and it can be potentially extended to crystals which properties are sensitive to local lattice variations. © 2016 The Royal Society of Chemistry.
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