274 research outputs found
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}
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