The thermal analysis of the oxide–chloride systems GdCl
3
–Gd
2
O
3
and GdCl
3
–KCl–Gd
2
O
3
with the Gd
2
O
3
content up to 0.09 mol fractions was studied in the temperature range 298–1173 K using ...two methods: differential scanning calorimetry and the method of cooling curves. The liquidus temperatures in these systems have been determined. The solubility of the oxide and the thermodynamic characteristics of the dissolution process were calculated. It was established experimentally that the dissolution of Gd
2
O
3
proceeds by a chemical mechanism, with the formation of GdOCl oxychloride. The received data revealed the main regularities of Gd
2
O
3
solubility in molten GdCl
3
–KCl–Gd
2
O
3
systems.
The structure, conductivity, melting points and caloric melting effects of the (Li2CO3?Na2CO3?K2CO3)eut melt/MgO nanopowder heterogeneous system with MgO concentration up to 70 vol. % have been ...investigated. A wide variety of methods (DSC, XRD, BET, high resolution scanning electron microscope, AC impedance method, IR and Raman spectroscopy) were used to evaluate samples and research. It is revealed that at the values of effective thickness of the salt phase interlayer between MgO particles below 100 nm there is an abrupt decrease in the melting points of the salt and the normalized phase transition enthalpy of the heterogeneous system. The activation energy of the electrical conductivity rises as the values of effective thickness of the melt phase interlayer between MgO particles decreases. The study established the lack of any chemical interaction between MgO and carbonate melt at 400?600??. In situ Raman spectroscopy of the (Li2CO3?Na2CO3?K2CO3)eut melt/MgO nanopowder systems revealed the solvation of solid particles by salt-melt ions.
Interaction between SiO2 and a KF–KCl–K2SiF6 Melt Zaykov, Yurii P; Isakov, Andrey V; Zakiryanova, Irina D ...
The journal of physical chemistry. B,
02/2014, Letnik:
118, Številka:
6
Journal Article
Recenzirano
The solubility mechanism of silica in a fluoride–chloride melt has been determined in situ using Raman spectroscopy. The spectroscopy data revealed that the silica solubility process involved Si–O ...bond breakage and Si–F bond formation. The process results in the formation of silicate complexes, fluorine-bearing silicate complexes, and silicon tetrafluoride in the melt. Mass spectrometry of the vapor phase over the KF–KCl–K2SiF6 and KF–KCl–K2SiF6–SiO2 melts and differential scanning calorimetry coupled with thermal gravimetric analysis of these melts were performed to verify the silica solubility mechanism.
The electrical conductivity of LiCl?GdCl3 molten systems with the gadolinium chloride additions ranging from 0 to 23 mol % was measured depending on both the temperature and concentration of GdCl3. ...The molar conductivity of the molten GdCl3?LiCl system is calculated taking into account the assumption of additivity of the molar volume of the mixture. The obtained temperature dependencies can be approximated by Arrhenius-type equation. The effective activation energy, Ea, increased with the GdCl3 content. The liquidus temperatures of the studied systems were determined by differential scanning calorimetry. The high-temperature Raman spectra of LiCl?GdCl3 chloride melts were recorded. In addition, the conductivity of 0.77LiCl?0.23GdCl3 molten system with 1 mol % of Gd2O3 was measured. The investigation demonstrates that the addition of gadolinium oxide results in a decrease of the conductivity of the chloride molten system and growth of its liquidus temperature
Modifying lithium niobate cation composition improves not only the functional properties of the acousto- and optoelectronic materials as well as ferroelectrics but elevates the protonic transfer in ...LiNbO3-based electrolytes of the solid oxide electrochemical devices. Molten chlorides and other thermally stable salts are not considered practically as the precursors to synthesize and modify oxide compounds. This article presents and discusses the results of an experimental study of the full or partial heterovalent substitution of lithium ion in nanosized LiNbO3 powders and in the surface layer of LiNbO3 single crystal using molten salt mixtures containing calcium, lead, and rare-earth metals (REM) chlorides as the precursors. The special features of heterovalent ion exchange in chloride melts are revealed such as hetero-epitaxial cation exchange at the interface PbCl2-containing melt/lithium niobate single crystal; the formation of Li(1−x) Ca(x/2)V(x/2)Li+ NbO3 solid solutions with cation vacancies as an intermediate product of the reaction of heterovalent substitution of lithium ion by calcium in LiNbO3 powders; the formation of lanthanide orthoniobates with a tetragonal crystal structure such as scheelite as the result of lithium niobate interaction with trichlorides of rare-earth elements. It is shown that the fundamental properties of ion-modifiers (ion radius, nominal charge), temperature, and duration of isothermal treatment determine the products’ chemical composition and the rate of heterovalent substitution of Li+-ion in lithium niobate.
The article is devoted to the analysis of the phenomenon of ethnocultural identity from the point of view of representatives of the cognitive approach. Ethno-cultural identity is represented as a ...hierarchy of models that includes social and individual characteristics, Self-images. Categorization and social comparison are recognized as the main mechanisms for the formation of ethno-cultural identity in this area. In the article special attention is paid to the personal factor, namely, personal autonomy and individual peculiarities of the personality development.
The mechanism and kinetic parameters of the interaction of the FLiNaK–CeF3 melt with water vapors and oxygen in the air atmosphere were determined using Raman and IR spectroscopy, XRD analysis, and ...thermodynamic modeling of processes. The presence of the 4CeF3(solution) + 6H2O (gas) + O2(gas) = 4CeO2(solid) + 12HF(gas) reaction, which disturbs the fluoride melt homogeneity, was verified in situ by Raman spectroscopy adopted for high-temperature, chemically aggressive fluoride systems. Based on the obtained spectral data, the type of the kinetic equation, order, and rate constant of the chemical reaction were determined. The concentration of cerium dioxide was found to increase linearly in time and a zero reaction order with respect to CeO2 was detected. The change in the concentration of CeO2 over time at T = 510 °C is described by the equation C = 0.085t; the reaction rate constant is 0.085 mol. %∙min−1. The obtained kinetic parameters may be used to model emergencies related with the depressurization of the coolant circuit or the working area of the molten salt reactor.
A direct reduction of solid ytterbium oxides into the metal in molten salts is a promising environmental friendly process. To understand the phenomena, which occur during the electrochemical ...ytterbium production, data on the structure of ytterbium-containing oxide-salt melts are required. In this study, using ab initio molecular dynamics and in situ Raman spectroscopy, we bring insight on the local structure of these systems by the examples of YbCl3–KCl chloride melt and Yb2O3–YbCl3–KCl oxide-chloride melt with a Yb2O3 concentration up to 2 mol%. We show that there are octahedral species YbCl6, which, with an increase in YbCl3 concentration, can combine into a weakly bonded network through the bridging chlorine anions. Ytterbium oxide in the chloride melt dissociates to form OYb3 ionic groups, which are incorporated into the melt structure.
•Octahedral groupings YbCl6 are present in the YbCl3–KCl melts.•YbCl6 groupings could conjugate together to form weakly bonded extended structures.•Yb2O3 dissociates in chloride melt with the formation of OYb3 groupings.
•According to the Raman spectroscopy, the octahedral species GdCl6 are present in the LiCl–GdCl3 melts.•The Gd-based groupings are joined by various numbers of shared chlorine anions to form weakly ...bonded extended structures.•Gd2O3 in the chloride melt dissociates to form Gd2OLi groups, which are incorporated into the melt structure.•The local structure of the potassium-containing melt is more stable as compared to that of the lithium-containing melt.
Currently, the novel technologies of gadolinium electrochemical production from raw oxide materials using molten oxide-salt media are being developed. To understand the phenomena, data on the structure of gadolinium-containing oxide-salt melts are required. In this study, using ab initio molecular dynamics (AIMD) and in situ Raman spectroscopy, we bring insight on local structure details and ion dynamics in these systems by the examples of LiCl–GdCl3, KCl–GdCl3 chloride melt and LiCl–GdCl3–Gd2O3 oxide-chloride melt with a Gd2O3 concentration up to 2 mol %. The Raman spectroscopy reveals the octahedral species GdCl6. According to the AIMD, the Gd-based groupings are joined by various numbers of shared chlorine anions. Gadolinium oxide in the chloride melt dissociates to form Gd2OLi groups, which are incorporated into the melt structure. The calculated self-diffusion coefficients of ions and the lifetimes of ion pairs showed that the local structure of the potassium containing melt is more stable as compared to that of the lithium containing melt, which is closely concurring with the divergence in conductivities of these melts. LiGdO2 and GdOCl phases were found in the solidified oxide-chloride melt LiCl–GdCl3–Gd2O3. It has been suggested that the complex oxide LiGdO2 is formed by the reaction Gd2O3 + LiCl → GdOCl + LiGdO2. Based on the obtained data, it was concluded that lithium-containing chloride melt should be considered not only as a solvent for gadolinium oxide, but also as an active reaction medium. Here, lithium is involved in ongoing chemical reactions and participate in reaction product.
The problem of ethnocultural identity as a person’s idea of oneself, formed when a person realizes one’s own involvement in a particular ethnic group according to certain parameters of ethnogenesis: ...racial-biological (ancestral roots), climatic-geographical (historical territory) and sociocultural (the history of one’s people, ethnic symbols of culture and religion, etc.) – is directly related to the problem of studying cultural and historical features of individual countries and regions development in the context of a civilizational approach. The purpose of this work is a theoretical analysis of the civilizational approach, the possibility of its application in the study of the problem of young people’s ethnocultural identity formation based on folk traditions, customs and rituals. The source of the material was articles published in periodicals (Identities-Global Studies in Culture and Power, Journal of Multicultural Counseling and Development, European Journal of Social Theory, etc., as well as publications of famous researchers (Vengerov A.B., Kornetov G.B., Panarin A.S., Toynbee A.J., Spengler, O., Huntington S.P., etc.). The following general scientific research methods are used to achieve the goal: analysis of scientific sources and synthesis of various theories and concepts on the research problem, their comparison, generalization of research results, identification of features of the civilizational approach in terms of studying possible ways of ethnocultural identity formation were used. The application of dialectical analysis of the designated problem allowed the authors to study ethnocultural identity phenomenon in the universal interrelation of philosophical, sociological and pedagogical sciences, to identify patterns and trends inherent in the process of ethnocultural identity formation, which combined all the versatile aspects into a single integrity and revealed on the basis of this a general holistic picture of the process of ethnocultural identity formation. Possible directions in the work on this phenomenon formation are identified: reliance on mankind’s cumulative experience, on the achievements of all sciences and culture in general; the study of ethnoculture and all its structural elements; the study of the world historical and pedagogical process in the center of which is a person who masters the culture created by previous generations and transforms this culture and oneself in the course of this development. The significance of the obtained results is that the civilizational approach allows, firstly, to carry out a retrospective analysis of the problem of young people’s ethnocultural identity formation based on folk traditions, customs and rituals in the context of the dynamics of the past, present and future; secondly, to justify the need to form young people’s ethnocultural identity formation based on folk traditions, customs and rituals as one of the significant components in the system of individual’s self-image; thirdly, to substantiate the possibility of using ethnoculture, the core of which are traditions, customs and rituals as the basic values of each nation, in the process of young people’s ethnocultural identity formation in modern sociocultural conditions.
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