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1.


   
    Anisotropy of piezocaloric effect at ferroelectric phase transitions in ammonium hydrogen sulphate / E. A. Mikhaleva, M. V. Gorev, M. S. Molokeev [et al.] // J. Alloys Compd. - 2020. - Vol. 839. - Ст. 155085, DOI 10.1016/j.jallcom.2020.155085. - Cited References: 31. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023 ). X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS" . - ISSN 0925-8388
Кл.слова (ненормированные):
Piezocaloric effect -- Phase transition -- Ferroelectrics -- Thermal expansion -- High-pressure -- Entropy
Аннотация: The role of anisotropy of the thermal expansion in formation of piezocaloric effect (PCE) near ferroelectric phase transitions in NH4HSO4 was studied. Strong difference in linear baric coefficients and as a result in intensive and extensive PCE associated with the different crystallographic axes was found. PCE giving the main contribution to the barocaloric effect were determined at both phase transitions. Rather strong effect of the lattice dilatation on the tuning of PCE was observed. Comparative analysis of PCE at the phase transitions in different materials showed that NH4HSO4 can be considered as a promising solid-state refrigerant. A hypothetical cooling cycle based on alternate using uniaxial pressure along two axes was considered.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Department of Physics, Far Eastern State Transport University, Khabarovsk, 680021, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Flerov, I. N.; Флёров, Игорь Николаевич
}
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2.


   
    Anomalous behaviour of thermodynamic properties at successive phase transitions in (NH4)3GeF7 / E. V. Bogdanov [et al.] // J. Solid State Chem. - 2017. - Vol. 256. - P. 162-167, DOI 10.1016/j.jssc.2017.09.010. - Cited References: 23. - The reported study was partially supported by the Russian Foundation for Basic Research, research project no. 15-02-02009 a. . - ISSN 0022-4596
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Heat capacity -- Entropy -- Thermal expansion -- High pressure
Аннотация: Heat capacity, thermal dilatation, susceptibility to hydrostatic pressure and dielectric properties associated with succession of three phase transitions below room temperature in double fluoride salt (NH4)3GeF7 were studied. A possible transformation into the parent Pm-3m cubic phase was not observed up to the decomposition of compound. Nonferroelectric nature of structural distortions was confirmed. The DTA under pressure studies revealed a high temperature stability of two phases: P4/mbm and Pbam. The entropies of the phase transitions agree well with the model of structural distortions. Analysis of the thermal properties associated with the individual phase transitions in the framework of thermodynamic equations has shown a high reliability of the data obtained. © 2017 Elsevier Inc.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, Russian Federation
Institute of Chemistry, Far Eastern Department of RAS, Vladivostok, Russian Federation

Доп.точки доступа:
Bogdanov, E. V.; Богданов, Евгений Витальевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Pogoreltsev, E. I.; Погорельцев, Евгений Ильич; Gorev, M. V.; Горев, Михаил Васильевич; Laptash, N. M.; Flerov, I. N.; Флёров, Игорь Николаевич
}
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3.


   
    Calorimetric, dilatometric and DTA under pressure studies of the phase transitions in elpasolite (NH4)2KZrF7 / M. V. Gorev, A. V. Kartashev, E. V. Bogdanov [et al.] // J. Fluor. Chem. - 2020. - Vol. 235. - Ст. 109523, DOI 10.1016/j.jfluchem.2020.109523. - Cited References: 45. - The reported study was funded by RFBR according to the research project No. 18-02-00269 a. X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS" . - ISSN 0022-1139
Кл.слова (ненормированные):
Phase transition -- Fluorides -- Heat capacity -- Entropy -- Thermal expansion -- High pressure
Аннотация: Heat capacity, thermal expansion, and sensitivity to the hydrostatic pressure of (NH4)2KZrF7 elpasolite are studied in a wide temperature range. The changes in deformation and entropy during successive phase transitions are determined: Δ(ΔV/V) = 3·10−4; ΔS = 8 J/mol K The temperatures and entropies of phase transitions turned out to be slightly sensitive to pressure changes. An analysis of the entropy of phase transformations was performed in the framework of the model of the cubic phase structure Fm-3 m. In the low temperature phase, an anomalous behavior of thermodynamic properties, which is not characteristic of phase transitions, was observed, accompanied by a significant change in the crystal lattice entropy.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Astafijev Krasnoyarsk State Pedagogical University, Krasnoyarsk, 660049, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation
Institute of Chemistry, Far Eastern Department of RAS, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Kartashev, A. V.; Карташев, Андрей Васильевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Flerov, I. N.; Флёров, Игорь Николаевич; Laptash, N. M.
}
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4.


   
    Chemical pressure as an effective tool for tuning the structural disordering and barocaloric efficiency of complex fluorides (NH4)3MF7 (M: Sn, Ti, Ge, Si) / I. N. Flerov, M. V. Gorev, E. V. Bogdanov, N. M. Laptash // J. Phys. D: Appl. Phys. - 2024. - Vol. 57, Is. 17. - Ст. 175301, DOI 10.1088/1361-6463/ad211b. - Cited References: 39. - The study was supported by a Grant from the Russian Science Foundation No. 23-22-00115, https://rscf.ru/project/23-22-00115/ . - ISSN 0022-3727. - ISSN 1361-6463
Кл.слова (ненормированные):
fluorides -- phase transformation -- phase diagram -- entropy -- pressure -- barocaloric effect
Аннотация: Double fluoride salts (NH4)3M4+F7 (M4+: Sn, Ti, Ge, Si) demonstrate a high efficiency of using chemical pressure as a tool for control and tuning structural ordering/disordering, sensitivity to hydrostatic pressure, successions of the phase transitions, etc and, as a result, for purposeful variation within a wide range of parameters of barocaloric effect (BCE). The conventional and inverse BCEs near the triple points were found on the T − p phase diagrams, combination of which can be used to construct original cooling cycle in narrow temperature and pressure ranges. Reconstructive transformation between two cubic phases, Pm3-m ↔ Pa3-, realized in (NH4)3SnF7 at atmospheric pressure and in (NH4)3TiF7 at p ˃ 0.4 GPa are characterized by rather low thermal hysteresis, δT0 = 1 K, and a great entropy change, ΔSBCE = 110–152 J (kg · K)−1, depending on the size of the central atom. At above 300–350 K, a contribution to BCE associated with the regular thermal expansion of the crystal lattice becomes comparable to entropy and temperature changes under pressure in the region of the phase transitions. An analysis of the absolute, relative and integral barocaloric characteristics of (NH4)3M4+F7 compounds showed their high competitiveness with respect to other barocaloric materials considered as promising solid-state refrigerants.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, 660074 Krasnoyarsk, Russia
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, 660049 Krasnoyarsk, Russia
Institute of Chemistry, Far Eastern Department of RAS, 690022 Vladivostok, Russia

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Gorev, M. V.; Горев, Михаил Васильевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Laptash, N. M.
}
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5.


    Gorban, A.
    Codon usage trajectories and 7-cluster structure of 143 complete bacterial genornic sequences / A. . Gorban, T. . Popova, A. . Zinovyev // Physica A. - 2005. - Vol. 353. - P. 365-387, DOI 10.1016/j.physa.2005.01.043. - Cited References: 46 . - ISSN 0378-4371
РУБ Physics, Multidisciplinary
Рубрики:
DNA-BASE COMPOSITION
   ASYMMETRIC SUBSTITUTION PATTERNS

   PROTEIN-CODING REGIONS

   MICROBIAL GENOMES

   GENE IDENTIFICATION

   MARKOV-MODELS

   G+C CONTENT

   BIAS

   PREDICTION

   SELECTION

Кл.слова (ненормированные):
genome -- cluster -- codon usage -- correlations -- entropy -- mean field -- Cluster -- Codon usage -- Correlations -- Entropy -- Genome -- Mean field -- Approximation theory -- Correlation methods -- Database systems -- Entropy -- Functions -- Genes -- Mathematical models -- Clusters -- Codon usage -- Genomes -- Mean field -- Bacteria
Аннотация: Three results are presented. First, we prove the existence of a universal 7-cluster structure in all 143 completely sequenced bacterial genomes available in Genbank in August 2004, and explained its properties. The 7-cluster structure is responsible for the main part of sequence heterogeneity in bacterial genomes. In this sense, our 7 clusters is the basic model of bacterial genome sequence. We demonstrated that there are four basic "pure" types of this model, observed in nature: "parallel triangles", "perpendicular triangles", degenerated case and the flower-like type. Second, we answered the question: how big are the position-specific information and the contribution connected with correlations between nucleotide. The accuracy of the mean-field (context-free) approximation is estimated for bacterial genomes. We show that codon us-age of bacterial genomes is a multi-linear function of their genomic G+C-content with high accuracy (more precisely, by two similar functions, one for eubacterial genomes and the other one for archaea). Description of these two codon-usage trajectories is the third result. All 143 cluster animated 3D-scatters are collected in a database and is made available on our web-site: http://www.ihes.fr/similar to zinovyev/7clusters. (c) 2005 Elsevier B.V. All rights reserved.

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Держатели документа:
Univ Leicester, Dept Math, Leicester LE1 7RH, Leics, England
RAS, SB, Inst Computat Modelling, Krasnoyarsk, Russia
Bures Sur Yvette & Bioinformat Serv Inst Curie, Inst Hautes Etudes Sci, Paris, France
ИВМ СО РАН
Department of Mathematics, University of Leicester, Leicester, University Road, Leicester LE1 7RH, United Kingdom
Institute of Computational Modelling, SB RAS, Krasnoyarsk, Russian Federation
Institut des Hautes Etudes Scientifiques, Bures-sur-Yvette and Bioinformatics Service of Institut Curie, Paris, France

Доп.точки доступа:
Popova, T.; Zinovyev, A.
}
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6.


   
    Comparative analysis of elastocaloric and barocaloric effects in single-crystal and ceramic ferroelectric (NH4)2SO4 / E. Mikhaleva, M. Gorev, V. Bondarev [et al.] // Scripta Mater. - 2021. - Vol. 191. - P. 149-154, DOI 10.1016/j.scriptamat.2020.09.030. - Cited References: 47. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023 ). X-ray and dilatometric data were obtained using the equipment of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS” . - ISSN 1359-6462
Кл.слова (ненормированные):
Polymorphic phase transformation -- Phase diagram -- Order–disorder phenomena -- Entropy -- Caloric effects
Аннотация: We report the influence of anisotropy and texture on elasto(ElCE)- and baro(BCE)-caloric effects in single-crystal and ceramic (NH4)2SO4. Inverse extensive and intensive ElCE in ceramics, (ΔSElCE)cer = 87 J/kg·K; ΔTAD = - 11.6 K), as well as in a single crystal along the ferroelectric axis a, (ΔSElCE)a = 115 J/kg·K; (ΔTAD)a = - 16 K, significantly exceed BCE, ΔSBCE = 75 J/kg·K; ΔTAD = - 9.8 K, even at low pressure ~ 0.3 GPa. Caloric parameters of ammonium sulphate are comparable with those for promising solid-state refrigerants.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Bondarev, V. S.; Бондарев, Виталий Сергеевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Flerov, I. N.; Флёров, Игорь Николаевич
}
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7.


    Gorev, M. V.
    Conventional and inverse barocaloric effects around triple points in ferroelastics (NH4)3NbOF6 and (NH4)3TiOF5 / M. V. Gorev, E. V. Bogdanov, I. N. Flerov // Scripta Mater. - 2017. - Vol. 139. - P. 53-57, DOI 10.1016/j.scriptamat.2017.06.022. - Cited References: 17 . - ISSN 1359-6462
Кл.слова (ненормированные):
Barocaloric effect -- Entropy -- Order-disorder phenomena -- Phase diagram -- Polymorphic phase transformation
Аннотация: We report the conventional and inverse barocaloric effect (BCE) in ferroelastics (NH4)3NbOF6 and (NH4)3TiOF5. We found a rich set of the structural phase transitions and triple points on the T − p phase diagrams. Extensive and intensive BCE near some transformations and around triple points in both crystals are outstanding (|∆ SBCE max | = 30–100 J/kg·K; |∆ TAD max | = 4–22 K) and can be achieved at low pressure 0.01–0.60 GPa.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Bogdanov, E. V.; Богданов, Евгений Витальевич; Flerov, I. N.; Флёров, Игорь Николаевич; Горев, Михаил Васильевич
}
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8.


   
    Conventional and inverse barocaloric effects in ferroelectric NH4HSO4 / M. V. Gorev [et al.] // J. Alloys Compd. - 2019. - Vol. 806. - P. 1047-1051, DOI 10.1016/j.jallcom.2019.07.273. - Cited References: 22 . - ISSN 0925-8388
Кл.слова (ненормированные):
Polymorphic phase transformation -- Phase diagram -- Order–disorder phenomena -- Entropy -- Barocaloric effect
Аннотация: In this study, the conventional and inverse barocaloric effects (BCE) in ferroelectric NH4HSO4 are reported. Maximum extensive and intensive BCE near order–disorder phase transition can be achieved at low pressure p≤0.1 GPa. Large thermal expansion of the crystal lattice plays a very important role in the developing conventional BCE and conversation between BCE of different sign in the narrow temperature range.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, Russian Federation
Institute of Engineering Systems and Energy, Krasnoyarsk State Agrarian University, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Gorev, M. V.; Горев, Михаил Васильевич; Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Flerov, I. N.; Флёров, Игорь Николаевич; Bogdanov, E. V.; Богданов, Евгений Витальевич
}
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9.


   
    Direct and indirect studies of the electrocaloric effect in single crystalline ferrielectric (NH4)2SO4 / V. S. Bondarev, E. A. Mikhaleva, M. V. Gorev, I. N. Flerov // J. Alloys Compd. - 2022. - Vol. 892. - Ст. 162130, DOI 10.1016/j.jallcom.2021.162130. - Cited References: 38. - The reported study was supported by the Russian Science Foundation (project no. 19-72-00023) . - ISSN 0925-8388
Кл.слова (ненормированные):
Ferrielectric -- Electrocaloric effect -- Phase transition -- Entropy
Аннотация: The influence of an electric field on the phase transition parameters and the electrocaloric response in ferrielectric (NH4)2SO4 was studied using a universal multifunctional adiabatic calorimeter. The very low sensitivity of the phase transition temperature to the electric field, dT0/dE ≈ 5·10-3 K/(kV/cm), was shown to be the reason for the low maximum value of the intensive electrocaloric effect, ΔTAD, at E = 11 kV/cm: direct and indirect measurements gave the values of 0.01 K and 0.05 K, respectively. However, the extensive electrocaloric response revealed by an analysis of the entropy–temperature–electric field phase diagram was relatively large, with a value of ΔSECE ≈ − 19 J/kg K, due to the significant contribution of a jump in the excess entropy to the total value, δS0/ΔS0 ~ 0.37. An additional irreversible increase in temperature under the electric field was associated with the Joule effect and indicated a significant electrical conductivity of ammonium sulphate.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russian Federation
Institute of Engineering Physics and Radioelectronics, Siberian Federal University, Krasnoyarsk, 660074, Russian Federation

Доп.точки доступа:
Bondarev, V. S.; Бондарев, Виталий Сергеевич; Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Gorev, M. V.; Горев, Михаил Васильевич; Flerov, I. N.; Флёров, Игорь Николаевич
}
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10.


   
    Disorder and phase transitions in oxyfluoride (NH4)(3)Ta(O-2)(2)F-4 / I. N. Flerov [et al.] // J. Fluor. Chem. - 2011. - Vol. 132, Is. 10. - P. 713-718, DOI 10.1016/j.jfluchem.2011.05.012. - Cited Reference Count: 19. - Гранты: This work was supported by the Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation (NSh-4645.2010.2). - Финансирующая организация: Council on Grants from the President of the Russian Federation for the Support of Leading Scientific Schools of the Russian Federation [NSh-4645.2010.2] . - ISSN 0022-1139
Рубрики:
HEAT-CAPACITY
   COMPLEXES

   RB2KTIOF5

   FLUORIDES

   CRYOLITE

Кл.слова (ненормированные):
cubic oxyfluorides -- structural disorder -- phase transitions -- entropy -- permittivity -- pressure effect -- cubic oxyfluorides -- entropy -- permittivity -- phase transitions -- pressure effect -- structural disorder
Аннотация: Calorimetric, X-ray, dielectric and DTA under pressure measurements have been performed on oxyfluoride (NH4)(3)Ta(O-2)(2)F-4. The succession of nonferroelectric phase transitions was found associated with the order-disorder processes. The comparative analysis tantalate with related niobate has revealed the important role of the central atom in the physical properties behavior, mechanism of structural distortions and barocaloric effect in oxyfluorides with the eight-coordinated anionic polyhedra. (C) 2011 Elsevier By. All rights reserved.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Siberian Dept, Krasnoyarsk 660036, Russia
Siberian Fed Univ, Krasnoyarsk 660074, Russia
RAS, Inst Chem, Far Eastern Dept, Vladivostok 690022, Russia

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Gorev, M. V.; Горев, Михаил Васильевич; Fokina, V. D.; Фокина, Валентина Дмитриевна; Bovina, A. F.; Бовина, Ася Федоровна; Bogdanov, E. V.; Богданов, Евгений Витальевич; Pogoreltsev, E. I.; Погорельцев, Евгений Ильич; Laptash, N. M.
}
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