329 research outputs found
A three stage model for adsorption of nonionic surfactants
Copyright @ 1993 American Institute of Physics.A three stage model for the adsorption of nonionic surfactants is proposed which makes use of existing theory from studies of random sequential adsorption. The model is simulated and the adsorption curves are found. The theory of random sequential adsorption is used to calculate the coverage exactly at the end of each of the three stages
Spin-polarized transport through a single-level quantum dot in the Kondo regime
Nonequilibrium electronic transport through a quantum dot coupled to
ferromagnetic leads (electrodes) is studied theoretically by the nonequilibrium
Green function technique. The system is described by the Anderson model with
arbitrary correlation parameter . Exchange interaction between the dot and
ferromagnetic electrodes is taken into account {\it via} an effective molecular
field. The following situations are analyzed numerically: (i) the dot is
symmetrically coupled to two ferromagnetic leads, (ii) one of the two
ferromagnetic leads is half-metallic with almost total spin polarization of
electron states at the Fermi level, and (iii) one of the two electrodes is
nonmagnetic whereas the other one is ferromagnetic. Generally, the Kondo peak
in the density of states (DOS) becomes spin-split when the total exchange field
acting on the dot is nonzero. The spin-splitting of the Kondo peak in DOS leads
to splitting and suppression of the corresponding zero bias anomaly in the
differential conductance.Comment: 9 pages, 7 figure
Indium rich InGaN solar cells grown by MOCVD
Cataloged from PDF version of article.This study focuses on both epitaxial growths of InxGa1-xN epilayers with graded In content, and the performance of solar cells structures grown on sapphire substrate by using metal organic chemical vapor deposition. The high resolution X-ray and Hall Effect characterization were carried out after epitaxial InGaN solar cell structures growth. The In content of the graded InGaN layer was calculated from the X-ray reciprocal space mapping measurements. Indium contents of the graded InGaN epilayers change from 8.8 to 7.1 % in Sample A, 15.7-7.1 % in Sample B, and 26.6-15.1 % in Sample C. The current voltage measurements of the solar cell devices were carried out after a standard micro fabrication procedure. Sample B exhibits better performance with a short-circuit current density of 6 mA/cm(2), open-circuit voltage of 0.25 V, fill factor of 39.13 %, and the best efficiency measured under a standard solar simulator with one-sun air mass 1.5 global light sources (100 mW/cm(2)) at room temperature for finished devices was 0.66 %
The influence of energetic surface heterogeneity on proton desorption during capillary filling of silica nanochannels
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