scholarly journals Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Fe-=SUB=-2-=/SUB=-(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

2020 ◽  
Vol 62 (8) ◽  
pp. 1216
Author(s):  
А.С. Ногай ◽  
А.А. Ногай ◽  
С.Ю. Стефанович ◽  
Ж.М. Солиходжа ◽  
Д.Е. Ускенбаев
Keyword(s):  
Phase Transitions ◽  
Ionic Conductivity ◽  
Single Crystals ◽  
Hot Pressing ◽  
Structural Changes ◽  
Structural Features ◽  
Polymorphic Transformations ◽  
Relaxation Polarization ◽  
Dipole Ordering

Abstract The problems of the structural features, the dielectric and conducting properties of Na_3Fe_2(PO_4)_3 polycrystals prepared by hot pressing have been studied. The Na_3Fe_2(PO_4)_3 polycrystals in the α and β phases are shown to have higher conducting properties than the α and β phases of the single crystals grown by the solution–melt method. The regularities of the appearance of the dipole ordering, the ionic and superionic conductivities related to phase transitions and structural changes in the {[Fe_2(PO_4)_3]^3–}_3∞ rhombohedral crystalline frame during polymorphic transformations are refined. The problems of the relaxation polarization in the α and β phases of Na_3Fe_2(PO_4)_3 are discussed. A model for explaining the dipole ordering and the ionic conductivity in Na_3Fe_2(PO_4)_3 is proposed.

scholarly journals Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Cr-=SUB=-2-=/SUB=-(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

2018 ◽  
Vol 60 (1) ◽  
pp. 25
Author(s):  
А.С. Ногай ◽  
С.Ю. Стефанович ◽  
А.А. Буш ◽  
Д.Е. Ускенбаев ◽  
А.А. Ногай
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Low Temperature ◽  
Phase Transformations ◽  
Structural Changes ◽  
High Ionic Conductivity ◽  
Relaxation Polarization ◽  
Dipole Ordering

AbstractThe aspects of structure, dipole ordering, and ionic conductivity of the Na_3Cr_2(PO_4)_3 crystal with the four polymorphic phases (α, α', β, and γ) have been investigated. The features of the α-Na_3Cr_2(PO_4)_3 crystal structure and its dipole ordering and relaxation polarization in the low-temperature α and α' phases have been refined. The occurrence of Na_3Cr_2(PO_4)_3 dipole ordering in the α and α' phases and high ionic conductivity in the β and γ phases is attributed to the structural changes in the rhombohedral [ Me _2(PO_4)_3]^–3_3∞ crystal frame upon phase transformations α → α', α' → β, and β → γ. A model for explaining the dipole ordering and ionic conductivity phenomena in Na_3Cr_2(PO_4)_3 is proposed.

scholarly journals Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Sc-=SUB=-2-=/SUB=-(PO_4)-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (11) ◽  
pp. 2016
Author(s):  
А.С. Ногай ◽  
А.А. Ногай ◽  
С.Ю. Стефанович ◽  
Ж.М. Солиходжа ◽  
Д.Е. Ускенбаев
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Phase Transformations ◽  
Structural Changes ◽  
High Ionic Conductivity ◽  
Α Phase ◽  
Relaxation Polarization ◽  
Dipole Ordering

AbstractProblems of the dipole ordering and ionic conductivity of Na_3Sc_2(PO_4)_3 polycrystal that has three polymorphic phases—α, β, and γ—are studied. The features of the α-Na_3Sc_2(PO_4)_3 crystal structure and the dipole ordering and relaxation polarization in the α and β phases are specified. The origin of the dipole ordering in the α phase and the partial dipole disordering in the β-Na_3Sc_2(PO_4)_3, as well as the high ionic conductivity in the β and γ phases of the Na_3Sc_2(PO_4)_3 polycrystal are associated with phase transformations α → β, β → γ that result in structural changes of the rhombohedral {[Sc_2(PO_4)_3]^3–}_3∞ crystalline framework. A model explaining the emergence of the dipole ordering and the ionic conductivity phenomena in Na_3Sc_2(PO_4) is proposed.

Infrared Crystallography: Structural Refinement through Spectroscopy

1997 ◽  
Vol 51 (4) ◽  
pp. 568-573 ◽  
Author(s):  
J. Timothy Sage
Keyword(s):  
Single Crystals ◽  
Protein Function ◽  
Structural Changes ◽  
Structural Model ◽  
Structural Features ◽  
Heme Iron ◽  
Structural Refinement ◽  
Crystal Forms ◽  
X Ray ◽  
Quantitative Understanding

A method for determining the orientation of individual bonds within complex macromolecules from polarized IR measurements on oriented single crystals is described. At present, X-ray diffraction is the principal technique used to define the global structure and orientation of macromolecules in the crystalline state. However, resolution limitations and conformational disorder limit the accuracy of the resulting structural model. A quantitative understanding of protein function often requires a more precise description of structural features at a localized active site. Polarized IR measurements of internal stretching bands of N−3, CN−, OCN−, and SCN− bound at the ferric heme iron of single crystals of myoglobin are presented. A synthesis of such measurements on different crystal forms leads to an N−3 orientation consistent with IR measurements on both P21 and P212121 crystals, but significantly different from the orientation reported in X-ray crystal structures. Subtle structural changes between these two crystal forms of the CN− complex may account for small differences in the stretching frequency and orientation of the C–N bond.

MmHn(XO4)(m + n)/2crystals: structure, phase transitions, hydrogen bonds, conductivity. II. Structure and properties of Cs3(HSO4)2(H2PO4) and Cs4(HSO4)3(H2PO4) single crystals

2016 ◽  
Vol 72 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Irina Makarova ◽  
Vadim Grebenev ◽  
Elena Dmitricheva ◽  
Ilya Vasiliev ◽  
Vladimir Komornikov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Optical Properties ◽  
Phase Transitions ◽  
Single Crystals ◽  
Structural Features ◽  
Structure And Properties ◽  
Structure Phase ◽  
Dielectric And Optical Properties ◽  
First Time

Cs3(HSO4)2(H2PO4) and Cs4(HSO4)3(H2PO4) single crystals were obtained for the first time based on a systematic study of the phase diagram of the CsHSO4–CsH2PO4–H2O ternary system. To reveal the structural conditionality for anomalies in physical properties, including dielectric and optical properties, diffraction studies of the crystal structure of Cs3(HSO4)2(H2PO4) and Cs4(HSO4)3(H2PO4) were performed, and their common structural features and differences were analyzed.

scholarly journals Magnetic phase transitions in Eu( Co1−xNix)2−yAs2 single crystals

2020 ◽  
Vol 4 (8) ◽  
Author(s):  
N. S. Sangeetha ◽  
Santanu Pakhira ◽  
D. H. Ryan ◽  
V. Smetana ◽  
A.-V. Mudring ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystals ◽  
Magnetic Phase ◽  
Magnetic Phase Transitions

scholarly journals Interaction of Lactoferrin with Unsaturated Fatty Acids: In Vitro and In Vivo Study of Human Lactoferrin/Oleic Acid Complex Cytotoxicity

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1602
Author(s):  
Anna Elizarova ◽  
Alexey Sokolov ◽  
Valeria Kostevich ◽  
Ekaterina Kisseleva ◽  
Evgeny Zelenskiy ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Structural Changes ◽  
Unsaturated Fatty Acids ◽  
Structural Features ◽  
Control Group ◽  
Acid Complex ◽  
Hepatoma 22A ◽  
Constitutive Parameters

As shown recently, oleic acid (OA) in complex with lactoferrin (LF) causes the death of cancer cells, but no mechanism(s) of that toxicity have been disclosed. In this study, constitutive parameters of the antitumor effect of LF/OA complex were explored. Complex LF/OA was prepared by titrating recombinant human LF with OA. Spectral analysis was used to assess possible structural changes of LF within its complex with OA. Structural features of apo-LF did not change within the complex LF:OA = 1:8, which was toxic for hepatoma 22a cells. Cytotoxicity of the complex LF:OA = 1:8 was tested in cultured hepatoma 22a cells and in fresh erythrocytes. Its anticancer activity was tested in mice carrying hepatoma 22a. In mice injected daily with LF-8OA, the same tumor grew significantly slower. In 20% of animals, the tumors completely resolved. LF alone was less efficient, i.e., the tumor growth index was 0.14 for LF-8OA and 0.63 for LF as compared with 1.0 in the control animals. The results of testing from 48 days after the tumor inoculation showed that the survival rate among LF-8OA-treated animals was 70%, contrary to 0% rate in the control group and among the LF-treated mice. Our data allow us to regard the complex of LF and OA as a promising tool for cancer treatment.

Phase transitions in PbZr0.72Sn0.28O3 single crystals studied by Raman spectroscopy

2016 ◽  
Vol 89 (7-8) ◽  
pp. 768-776 ◽  
Author(s):  
Irena Jankowska-Sumara ◽  
Min-Seok Jeong ◽  
Jae-Hyeon Ko ◽  
Andrzej Majchrowski ◽  
Józef Żmija
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transitions ◽  
Single Crystals
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