Synthesis of Pb, Fe and Cd doped Hg-based HgBa 2 Ca 2 Cu 3 O 8+δ (Hg-1223) superconducting ceramics was performed. Hg-free precursor Ba 2 Ca 2 Cu 3 O 8+δ with high chemical homogeneity and reactivity obtained by the sol-gel method was used. The superconducting and impurity phases were determined by means of scanning electron microscopy and microprobe analysis. The results of resistivity and magnetization measurements for different kinds of doped elements were presented.
It is presented the results of studies carried out over a wide temperature range (4–900 K) on investigation of the thermoelectric coefficient of RNi4+xGa1-x (R = Ce, La; 0 ≤ x ≤ 0.5) solid solutions containing cerium in an unstable valence state. The contribution of cerium f-states to the thermopower of CeNi4Ga is analyzed based on these results, taking into account the transport properties of the crystal matrix containing the f-electron subsystem. It is shown that the temperature behavior of the CeNi4Ga thermopower is caused by the joint effects of the incoherent Kondo scattering of conduction electrons in localized f-centers and scattering by spin fluctuations in the narrow d-band of the nickel sublattice. It is suggested that the anomalously low Kondo contribution to the total thermopower observed in this case should be associated with a possible decrease in the Kondo compensation of the magnetic moment of cerium ions, due to the structural atomic disorder in its immediate environment.
The temperature variations of the thermoelectric power coefficients of the Hg-based high-temperature superconductors HgBa2Can−1CunO2n+2+δ (n = 1, 2, 3) with oxygen doping and cation substitutions are analyzed in terms of a narrow conduction band model. The parameters of the band spectrum in the vicinity of the Fermi level are determined and the manner in which they transform is examined. A correlation is found between the effective band width and the superconducting transition temperature Tc.
Functional components of the landscape units, phases and tracts of the suburban forest area of Lviv Vynnyky were analyzed. Case study of the forest geosystems, such as, for example, the landscape phases, shows the research of biometrical index of the forests which are concentrated specifically in this area. On the drawings of the landscape phases of this specific area the division of the forests, which shows the full picture of their areal division, is shown. Key words: landscape phases, landscape tracts, forest geosystems, suburban forest area of Lviv Vynnyky.
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