ВЛИЯНИЕ КИСЛОРОДНЫХ ВАКАНСИЙ В Sro-ПЛОСКОСТЯХ НА Тc(X)-ЗАВИСИМОСТЬ КРИСТАЛЛОВ BI2SR2–XLAXCUO6+δ
We report the first systematic study of the effect of oxidizing annealing on the superconducting transition temperature Tc of Bi2Sr2 – xLaxCuO6 + δ crystals. Using a standard heat treatment procedure, we have obtained detailed Tc(x) data for Bi2Sr2 – xLaxCuO6 + δ crystals in the range x = 0.35–0.75. Comparison of the shape of the Tc(x) curve for Bi2Sr2 – xLaxCuO6 + δ with that for La2 – xSrxCuO4 demonstrates a factor of 4 reduction in the dependence of hole concentration in the CuO2 planes from a La3+ substitution on the Sr2+ sites becouse oxygen content (or index) varies. This finding can be accounted for in terms of changes in the amount of oxygen vacancies in the SrO planes. In particular, the oxygen index in Bi2Sr2 – xLaxCuO6 + δ varies by 0.3 per formula unit.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.