759 research outputs found
Pressure-induced spin-state transition of iron in magnesiow\"ustite (Fe,Mg)O
We present a detailed theoretical study of the electronic, magnetic, and
structural properties of magnesiow\"ustite FeMgO with in the
range between 00.875 using a fully charge self-consistent implementation of
the density functional theory plus dynamical mean-field theory (DFT+DMFT)
method. In particular, we compute the electronic structure and phase stability
of the rock-salt B1-structured (Fe,Mg)O at high pressures relevant for the
Earth's lower mantle. We obtain that upon compression paramagnetic (Fe,Mg)O
exhibits a spin-state transition of Fe ions from a high-spin to low-spin
(HS-LS) state which is accompanied by a collapse of local magnetic moments. The
HS-LS transition results in a substantial drop of the lattice volume by about
48 %, implying a complex interplay between electronic and lattice degrees of
freedom. Our results reveal a strong sensitivity of the calculated transition
pressure upon addition of Mg. While for Fe-rich
magnesiow\"ustite, Mg , exhibits a rather weak variation
at 80 GPa, for Fe-poor (Fe,Mg)O it drops, e.g., by about 35 % to 52 GPa
for Mg . This behavior is accompanied by a substantial change of the
spin transition range from 50140 GPa in FeO to 3090 GPa for . In
addition, the calculated bulk modulus (in the HS state) is found to increase by
12 % from 142 GPa in FeO to 159 GPa in (Fe,Mg)O with Mg . We
find that the pressure-induced HS-LS transition has different consequences for
the electronic properties of the Fe-rich and poor (Fe,Mg)O. For the Fe-rich
(Fe,Mg)O, the transition is found to be accompanied by a Mott insulator to
(semi-) metal phase transition. In contrast to that, for , (Fe,Mg)O
remains insulating up to the highest studied pressures, implying a Mott
insulator to band insulator phase transition at the HS-LS transformation.Comment: 9 pages, 9 figure
The role of transnational companies in urban development
The paper is about the impact of globalization and transnational companies, their importance and the influence on the urban economic development. Globalization has significant implications for all types of cities, determining actions and the policy of governments and corporations in international relationships. In the international competitive environment, the ability to develop a transnational organizational capability is the key factor that can help the firm adapt to the changes in the dynamic environment, at the same time, to become valuable for a new internationalized world, cities have to develop themselves constantly
Analysis of priority sectors of the economy in the policy of import substitution
In this paper, the authors considered the priority sectors of the economy in the policy of import substitution. Analyses were carried outthe work of foreign and domestic scientistproposed the author's interpretation of the import substitution policy, presentedthe scheme of work of the industry of import substitution in the Russian Federatio
Actual problems of education of children in educational institution
The article describes the current problems of children`s education in general educational institutions. We consider the problem of poor awareness among parents, maintain and enhance the quality of education, the problem of moral education of children, the impossibility of applying an individual approach to the student, the problem of efficiency of the educational systemВ статье раскрываются актуальные проблемы воспитания детей в общеобразовательных учреждениях. Рассматриваются проблемы низкой информированности родителей, сохранения и повышения качества образования, проблемы нравственного воспитания детей, проблемы невозможности применения индивидуального подхода к ученику, проблемы эффективности системы воспитани
Classification of double flag varieties of complexity 0 and 1
A classification of double flag varieties of complexity 0 and 1 is obtained.
An application of this problem to decomposing tensor products of irreducible
representations of semisimple Lie groups is considered
Arc Magmas from Slab to Eruption: The Case of Kliuchevskoy Volcano
Arc magmas are generated by a number of mantle and
crustal processes. Our multidisciplinary, long-term research is
aimed at deciphering these processes for a single arc volcano,
Kliuchevskoy volcano in Kamchatka. Some key results of the
study follow:
1) Modeling of trace element and H2O contents in melt
inclusions suggests that the primary magmas originate via
hydrous flux-melting of the mantle wedge at temperatures
close to the dry peridotite solidus. The role of decompression
melting is minor or absent at Kliuchevskoy and other arc
volcanoes built on relatively thick crust.
2) Geochemistry of high-Mg olivine suggests that primary
Kliuchevskoy magmas have substantial contribution from
olivine-free pyroxenite (up to 30 %), which could be formed
by reaction of slab melts (or supercritical fluids) with mantle
wedge peridotite.
3) Parental Kliuchevskoy melts start to crystallize as deep
as the Moho boundary, and the erupted magmas reflect multistage
and complex processes of crystallization, magma mixing
and crustal assimilation. None of the Kliuchevskoy rocks
analyzed thus far represent true primary melt compositions.
4) The Kliuchevskoy Holocene eruptive history is not
steady-state in terms of eruption rate and geochemistry. There
are two millenial cycles with major and trace element and OSr-
Nd-Pb and U-series isotope compositions of the magmas
changing gradually from more to less affected by crustal (?)
assimilation. The onset of the cycles correlates with periods of
enhanced volcanic activity in Kamchatka, suggesting that the
extent of magma-crust interaction is inversely related to
magma production rate and thus magma flux from the mantle
Theoretical and methodological grounds for the modernization of the tax administration system
The article stands for the theoretical underpinning of economic grounds of tax system and its building on the basis of social- and business-oriented socioeconomic features.
Authors proved the need for tax process management that represent the features of government-society-taxpayer relations with taxpayer’s leading role as macroeconomic tool for economic regulation process as well as providing the sustainable and balanced economic growth and innovative modernization of Russian economy.peer-reviewe
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