55 research outputs found
Structure Type of Hexagonal Tantalum Bronzes with Variable Composition K sub 6 Ta sub 6 + Z O sub 15 F sub 6 (F, O) sub y : Ta sup (5 -- delta) + Bronzes and Ta sup 5 + Compounds
COMPETITIVE STRATEGY IN THE FIELD OF EDUCATIONAL POTENTIAL
In the course of market reforms in the Russian economy there has been a trend of weakening its educational potential. The problems of access to education and the possibility of payment have exacerbated. Delay in the development of innovative models and raw primitivization economy resulted in decrease of intelligence needs and the demand for qualified professionals. Further, there arose difficulties in connection with the transition to the so-called two-tier education system â «Bachelor â Master.»On the basis of the circumstances mentioned in the article, the improvement of the Russian educational system in the direction of democratization and individualization of the learning process, referring to giving students a choice between different educational systems and modules, and various ways to improve studentsâ weight (the development of corporate education, the provision of learning opportunities created in the Russian branches of Western universities, the organization of NSO on market principles, the creation of youth discussion clubs, innovative student enterprises, competitions on market principles, the establishment of universitiesâ student avenues of glory, etc.)
KNb4O5F and NbO2 crystal structures. Structural aspect of chemical decomposition of K2-xNb4O3(O,F)(3)F in the melt of sodium and potassium chlorides
The structures of the KNb4O5F (I) (synthesized for the first time) and the NbO2 (II) phases formed together with NbO during decomposition of reduced oxofluoroniobate K2-xNb4O3(O,F)(3)F (III) in the (NaCl + KCl) melt are studied by X-ray methods. The tetragonal structures of compounds I and II are refined up to R = 0.06 and R = 0.0186, respectively. The unit-cell parameters are determined as a = 4.155(3) and c = 8.377(6) Angstrom, sp. gr. P4/mmm for compound I, a = 13.698(3) and c = 5.976(1) Angstrom, sp. gr. 14(1)/a for compound II, and a = 4.151(3) and c = 21.64(2) Angstrom, sp. gr. P4/mmm for compound III. Decomposition of compound III is considered in terms of different stabilities of its structural modules (the two-dimensional periodic NbO and the KF fragments). The formation of NbO and compound I is associated with the decomposition of KF fragments and the preservation of NbO fragments. In compound I, only one of two KF networks (similar to those separating the NbO fragments in compound III) is preserved. In NbO, two-dimensional condensed NbO fragments form a three-dimensional framework. Compound II has neither of the two modules observed in III, but the NbO4 squares forming an NbO fragment are preserved. The defects of the real structure of compound I, which give rise to the formation of a one-dimensionally disordered KNb4O5F structure, are analyzed. The discrepancies between the structural characteristics of compound II obtained in the present study and reported earlier are discussed. [References: 9
Two-dimensional plasma-wave interaction in an helicon plasma thruster with magnetic nozzle
Investigation of the structure of compacts and sheets of an Al-Cu-Li alloy strengthened by Al2CuLi (T1) particles
Structural states of the material of compacts and sheets made from an Al-Cu-Li alloy with silver
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