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We investigated the morphological, structural and electronic properties of Pentacene thin films grown by vacuum thermal evaporation on different inert substrates at room temperature. The results of our AFM and STM analysis give an interplanar spacing of 1.54 nm corresponding to the (0 0 1) distance of the so-called “thin film phase”. The STS measurements show an HOMO-LUMO gap of 2.2 eV. 相似文献
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Nash Equilibria,Variational Inequalities,and Dynamical Systems 总被引:2,自引:0,他引:2
Cavazzuti E. Pappalardo M. Passacantando M. 《Journal of Optimization Theory and Applications》2002,114(3):491-506
In this paper, we introduce some relationships between Nash equilibria, variational equilibria, and dynamical equilibria for noncooperative games. 相似文献
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L. Lozzi M. Passacantando P. Picozzi S. Santucci M. De Crescenzi 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,20(1):387-390
The electronic structure of small chromium clusters deposited by evaporation onto clean polycrystalline graphite has been studied by means of Auger, X-ray Photoemission (XPS) and Electron Energy Loss (EELS) spectroscopies. The XPS results show an increase in the binding energy of both core levels and valence band reducing the cluster size. The EELS measurements show a variation of the intensity ratio of L3-to-L2 ionization core edges. We interpret this change as due to different redistribution, within the clusterd-band, of the empty states above the Fermi level. As a consequence the XPS results may also be attributed to sizeable change of the electronic structure of the small clusters. 相似文献
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Barbara Panicucci Massimo Pappalardo Mauro Passacantando 《Computational Optimization and Applications》2009,43(2):197-211
We propose a descent method via gap functions for solving nonsmooth variational inequalities with a locally Lipschitz operator.
Assuming monotone operator (not necessarily strongly monotone) and bounded domain, we show that the method with an Armijo-type
line search is globally convergent. Finally, we report some numerical experiments.
This work has been supported by the National Research Program PRIN/2005017083 “Innovative Problems and Methods in Nonlinear
Optimization”. 相似文献
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V. Grossi M. Passacantando G. Impellizzeri L. Ottaviano 《Applied Surface Science》2008,254(24):8093-8097
Single crystal germanium nanowires have been grown by vapour-liquid-solid deposition onto silicon oxide substrates with Au catalyst nanoparticles. They have been doped by two different techniques: Ge and Mn co-evaporation during growth and post-growth Mn implantation. Scanning electron microscopy images show that Mn-implanted nanowires have a lower surface density and a smaller average diameter (18.8 nm) than the un-doped ones and those Mn doped by co-deposition. The effectiveness of Mn doping has been verified by X-ray photoemission spectroscopy and by energy-dispersive X-ray measurements, indicating in the two cases significant Mn atomic concentration in the nanowire. X-ray diffraction indicates that the nanowires are single crystals and that they do not contain precipitates of Mn extrinsic phases. Both SEM and XPS experimental evidences are in line to indicate that the Mn doping by ion implantation is preferable with respect to that one performed by co-evaporation as it reduces the thickness of the outer oxide sheath of the nanowires and their diameter. 相似文献
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Structural, optical and electrical characterization of antimony-substituted tin oxide nanoparticles 总被引:1,自引:0,他引:1
T. Krishnakumar Nicola Pinna M. Passacantando 《Journal of Physics and Chemistry of Solids》2009,70(6):993-850
Antimony-doped tin oxide (ATO) nanostructures were prepared using chemical precipitation technique starting from SnCl2, SbCl3 as precursor compounds. The antimony composition was varied from 5 to 20 wt%. The lower resistance was observed at composition of Sn:95 and Sb:05, when compared with undoped and higher doping concentration of antimony. The average crystalline size of undoped and doped tin oxide was calculated from the X-ray diffraction (XRD) pattern and found to be in the range of 30-11 nm and it was further confirmed from the transmission electron microscopy (TEM) studies. The scanning electron microscopy (SEM) analysis showed that the nanoparticles agglomerates forming spherical-shaped particles of few hundreds nanometers. The samples were further analyzed by energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and electrical resistance measurements. 相似文献
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U. Coscia G. Ambrosone A. Ambrosio M. Ambrosio F. Bussolotti V. Carillo V. Grossi P. Maddalena M. Passacantando E. Perillo A. Raulo S. Santucci 《Solid State Sciences》2009,11(10):1806-1809
Structural, optical and electrical properties of multiwalled carbon nanotubes deposited by chemical vapour deposition at 750 °C on sapphire substrate have been investigated. The main results concern the photoconductivity measurements. The photocurrent induced by white light illumination is a linear function of either the bias voltage or the optical power density in wide ranges. The photoresponse increases from the near infrared to the ultraviolet region with decreasing the wavelength of the monochromatic incident radiation in the 325–850 nm range. The photoresponse is strongly correlated to the optical absorbance. The optical and photoconductivity properties explored in multiwalled carbon nanotube samples with relatively large area appear very interesting for the development of light sensors. 相似文献
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S. Piperno L. Lozzi R. Rastelli M. Passacantando S. Santucci 《Applied Surface Science》2006,252(15):5583-5586
Electrospinning is a process by which polymer nanofibers (with submicron scale diameters) can be formed when a droplet of viscoelastic polymer solution is subjected to high voltage electrostatic field. As this droplet travels in air, the solvent evaporates leaving behind a charge fiber that can be electrically deflected on a substrate. A series of nanofibers with various wt.% of PMMA (poly-methyl-methacrylate) to acetone were produced and characterized regarding their morphology and chemical composition. The nanofibers were characterized by Secondary Electron Microscopy, Atomic force microscopy and X-ray photoelectron spectroscopy. 相似文献