Spin and energy transfer in nanocrystals without transport of charge

We describe a mechanism of spin transfer between individual quantum dots that does not require tunneling. Incident circularly-polarized photons create inter-band excitons with non-zero electron spin in the first quantum dot. When the quantum-dot pair is properly designed, this excitation can be transferred to the neighboring dot via the Coulomb interaction with either {\it conservation} or {\it flipping} of the electron spin. The second dot can radiate circularly-polarized photons at lower energy. Selection rules for spin transfer are determined by the resonant conditions and by the strong spin-orbit interaction in the valence band of nanocrystals. Coulomb-induced energy and spin transfer in pairs and chains of dots can become very efficient under resonant conditions. The electron can preserve its spin orientation even in randomly-oriented nanocrystals.Comment: 13 pages, 3 figure

Изучение кинетики сорбции отдельных компонентов композитного биосорбента

В данной статье исследуется кинетика сорбции уранил-ионов плесневыми грибами Penicillium pinophilum и Aspergillus niger. Исследования показали что степень сорбции плесневых грибов Aspergillus niger имеет на 3% большую степень сорбции урана, чем Penicillium pinophilum . Так же исследования показали, что после 12 часов сорбция заметно уменьшается и почти останавливается как у одно, так и у другого вида плесневых грибов. This article examines the kinetics of sorption of uranyl ions by fungi Penicillium pinophilum and Aspergillus niger. Studies have shown that the degree of sorption fungi Aspergillus niger has by 3% greater uranium sorption than the Penicillium pinophilum . Studies have shown that after 12 hours of sorption decreases markedly and almost stops as one or the other kind of fungi

Characterization of quasimonotonicity by means of functional inequalities

It is known that quasimonotonicity of a continuous function can be characterized by means of differential inequalities. Using this we give a characterization by means of functional inequalities

Stability of the Pexider functional equation

A stability result for the Pexider equation will be derived from a stability theorem published in [9] for the Cauchy functional equation. Then we discuss the quality of some constants occuring in this context; as a model case we consider functions defined on the multiplicative semigroup {1, 0}