Melt–vapor phase transition in the lead–selenium system at atmospheric and low pressure

The boiling temperature and the corresponding vapor phase composition in the existence domain of liquid solutions were calculated from the partial pressures of saturated vapor of the components and lead selenide over liquid melts in the lead–selenium system. The phase diagram was complemented with the liquid–vapor phase transition at atmospheric pressure and in vacuum of 100 Pa, which allowed us to judge the behavior of the components during the distillation separation.     

Structure of С@Al<Subscript>2</Subscript>O by multinuclear solid-state NMR spectroscopy

The ²⁷Al, ¹H MAS NMR method is used to study initial nanosized metastable aluminum oxides of a pseudoboehmite series (γ- and δ-Al₂O₃) after being coated with graphene (С@Al₂O₃) and annealed in the air (С@Al₂O₃-Т). It is demonstrated that aluminum nanoparticles coated with graphene and annealed at high temperatures (to 750°C for γ and 1180°C for δ) preserve their phase composition but differ from initial oxides by a very low concentration of defects (ОН groups). After the annealing of the graphene coating the hydroxyl cover of oxides is reduced, however, the set of ОН groups differs greatly from that of the initial oxides. Only one type of terminal ОН groups with a ~0.2 ppm shift and one type of bridging μ²-ОН groups with a 1.8 ppm shift for γ-Al₂O₃ from OH-μ²-AlVAl_n and 2.1 ppm for δ-Al₂O₃ OH-μ²-AlIVAl_n are observed. The data obtained make it possible to characterize in detail the δ-Al₂O₃ pure phase.     

Melt–gas phase equilibria and state diagrams of the selenium–tellurium system

The partial pressures of saturated vapor of the components in the Se–Te system are determined and presented in the form of temperature–concentration dependences from which the boundaries of the melt–gas phase transition are calculated at atmospheric pressure and vacuums of 2000 and 100 Pa. The existence of azeotropic mixtures is revealed. It is found that the points of inseparably boiling melts correspond to 7.5 at % of Se and 995°C at 101325 Pa, 10.9 at % at 673°C and 19.5 at % at 522°C in vacuums of 2000 and 100 Pa, respectively. A complete state diagram is constructed, including the fields of gas-liquid equilibria at atmospheric and low pressures, the boundaries of which allow us to assess the behavior of selenium and tellurium upon distillation fractionation.     

On the Relationship Between the Baum-Katz-Spitzer Complete Convergence Theorem and the Law of the Iterated Logarithm

For a sequence of i.i.d. Banach space-valued random variables {Xn; n ≥ 1} and a sequence of positive constants {an; n ≥ 1}, the relationship between the Baum-Katz-Spitzer complete convergence theorem and the law of the iterated logarithm is investigated. Sets of conditions are provided under which （i） lim sup n→∞ ｜｜Sn｜｜/an〈∞ a.s.and ∞ ∑n=1（1/n）P（｜｜Sn｜｜/an ≥ε〈∞for all ε 〉 λ for some constant λ ∈ [0, ∞） are equivalent; （ii） For all constants λ ∈ [0, ∞）, lim sup ｜｜Sn｜｜/an =λ a.s.and ^∞∑ n=1（1/n） P（｜｜Sn｜｜/an ≥ε）{〈∞, if ε〉λ =∞,if ε〈λare equivalent. In general, no geometric conditions are imposed on the underlying Banach space. Corollaries are presented and new results are obtained even in the case of real-valued random variables.     

O<Superscript>−</Superscript> radical anions on oxide catalysts: Formation,properties, and reactions

A systematic in situ EPR study of processes yielding O⁻ radical anions on the surface of oxide dielectrics (MgO, CaO), semiconductors (ZnO, TiO₂), supported systems (V/SiO₂), and zeolite FeZSM-5 is reported. Methodological approaches to the study of O-radical anions are considered for the cases in which these species are directly undetectable by EPR. Particular attention is focused on the development of methods of investigation of so-called α-oxygen on the FeZSM-5 surface, which is an O⁻ radical anion stabilized on the paramagnetic ion Fe³⁺. The reactions involving α-oxygen and the analogous reactions known for O-radical anions stabilized on the oxide surface are demonstrated to occur in similar ways. The photostimulated formation of spatially separated electron and hole centers on the surface of oxide systems is most likely due not to charge separation, but to the spatial separation of the radicals resulting from the homolytic photodissociation of chemisorbed water. A scheme is suggested for this process on the partially hydroxylated MgO surface.     

L 1-Convergence for Weighted Sums of Some Dependent Random Variables

In this article, the authors discuss the L ₁-convergence for weighted sums of some dependent random variables under the condition of h-integrability with respect to an array of weights. The dependence structure of the random variables includes pairwise lower case negative dependence and conditions on the mixing coefficient, the maximal correlation coefficient, or the ρ*-mixing coefficient. They prove that all the weighted sums have similar limiting behaviour.     

A Note on Complete Convergence for Arrays of Rowwise Independent Banach Space Valued Random Elements

We obtain complete convergence results for arrays of rowwise independent Banach space valued random elements. Compared with similar results presented in the probabilistic literature our conditions are weaker.     

Limiting behavior for arrays of rowwise ρ *-mixing random variables

We study the limiting behavior of maximal partial sums for arrays of rowwise ?? ^*-mixing random variables and obtain some new results that improve the corresponding theorem of Zhu [M.H. Zhu, Strong laws of large numbers for arrays of rowwise ?? ^*-mixing random variables, Discrete Dyn. Nat. Soc., 2007, Article ID 74296, 6 pp., 2007].     

Multilayer thin-film filters of extreme ultraviolet and soft X-ray spectral regions

Multilayer thin-film filters from different materi al pairs with spectral windows within the wavelength range 7n < 60 nm were developed. Optical characteristics of samples in the extreme ultraviolet, visible, and IR spectrum ranges were studied. Ultrathin freestanding Zr/Si large-aperture filters with transparencies up to 76% at 7n = 13 nm were manufactured for projection lithography test benches; variations in their properties during long-term thermal loads were studied.     

Electronic structure of Yb<Superscript>3+</Superscript> impurity centers in fluorites

The electronic structure and g factors of simple impurity centers and hexamer ytterbium clusters in fluorites have been calculated in terms of the exchange charge model. Preliminarily, their local crystal structures have been calculated in the framework of the shell model with the inclusion of lattice distortions near the impurity.