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111.
Simonetta Tuti Franco Pepe Daniela Pietrogiacomi Valerio Indovina 《Reaction Kinetics and Catalysis Letters》2001,72(1):35-42
On CoOx/ZrO2, CuOx/ZrO2 and FeOx/ZrO2 catalysts, below the limits shown by characterization to have high metal dispersion, the turnover frequency for N2O decomposition is nearly independent of metal content. 相似文献
112.
L. Lanotte G. Ausanio V. Iannotti G. Pepe G. Carotenuto L. Nicolais 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(4):485-489
A composite material of a polyethylene matrix filled by a fine silver powder was prepared with different Ag contents and physical
behaviours ranging from insulator to conductor. Ac differential magnetic susceptibility χ measurements show the samples are
paramagnetic up to an Ag concentration of ∼65%. At low temperatures the composite is spin-glass type, whereas the transition
from insulator to conductor corresponds to an abatement of χ at zero magnetizing field. Magneto-conductivity effects have
been observed in resistivity measurements at low temperatures. They can be explained in terms of an effective exchange electronic
scattering mechanism between the conduction electrons and the diluted magnetic moments arising from unpaired electron spins
of boundary silver particles. Moreover, the presence of a broad minimum in the resistivity curve at T = ∼ 20 K, observed in samples with an Ag concentration just above the percolation threshold, addresses to possible interference
effects similar to those reported in disordered materials.
Received 17 October 2000 and Received in final form 22 February 2001 相似文献
113.
Vincenza Antonucci Gabriella Faiella Michele Giordano Luigi Nicolais Gianpiero Pepe 《Macromolecular Symposia》2007,247(1):172-181
Composites of carbon nanotubes (CNT) in polymeric matrices have attracted considerable attention in the research communities due to their good electrical conductivity, high stiffness and high strength at relatively low CNT contents. Effective utilization of CNT in composites depends primarily on the ability to disperse them homogeneously throughout the polymer matrix, avoiding the formation of bundles due to van der Waals interactions existing between the nanotubes. In this work composites of polystyrene at various percentages of SWNT were fabricated using Latex Technology technique, a polymer type-independent method based on using a surfactant as a dispersing agent. An electrical characterization of SWNT composites was performed both in DC and AC modes. From the analysis of DC data a percolative behavior was found for the conductivity as function of SWNT content. The innovative contribution of this work consists in the modeling of the composite material upon its electrical properties. AC measurements and the analysis of impedance as function of angular frequency lead to the formulation of an equivalent circuit able to model the composite material in correspondence of the percolative threshold. 相似文献
114.
Preparation and characterization of nano-sized Ag/PVP composites for optical applications 总被引:2,自引:0,他引:2
G. Carotenuto G.P. Pepe L. Nicolais 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(1):11-17
A modification of the polyol process has enabled the direct synthesis of nm-sized Ag particles with narrow size distribution
and controlled average dimension embedded in a polymeric matrix. Dispersion of colloidal silver was obtained by reduction
of silver nitrate in ethylene-glycol in the presence of a polymeric protective agent (i.e., poly(N-vinylpyrrolidone)) and ultrasounds. The final particle size was controlled by removing the colloid from the reactive
mixture by addition of acetone. The very strong plasmon resonance peak at 410 nm and a feature at 350 nm in the UV-visible
spectra are a clear consequence of the nano-size of dilute Ag particles. The proposed process offers the possibility to effectively
use these synthesised materials for the production of colour filters for advanced optical devices.
Received 10 November 1999 相似文献
115.
Letizia Canziani Manuela Marenco Giorgio Cavenaghi Giulia Manfrinato Angelo Taglietti Alessandro Girella Carlo Aprile Giovanna Pepe Lorenzo Lodola 《Molecules (Basel, Switzerland)》2022,27(2)
Background: Macroaggregated human serum albumin (MAA) properties are widely used in nuclear medicine, labelled with 99mTc. The aim of this study is to improve the knowledge about the morphology, size, dimension and physical–chemical characteristics of MAA and their bond with 99mTc and 68Ga. Methods: Commercial kits of MAA (Pulmocis®) were used. Characterisation through experiments based on SEM, DLS and Stokes’ Law were carried out. In vitro experiments for Langmuir isotherms and pH studies on radiolabelling were performed and the stability of the radiometal complex was verified through competition reactions. Results: The study settles the MAA dimension within the range 43–51 μm. The Langmuir isotherm reveals for [99mTc]MAA: Bmax (46.32), h (2.36); for [68Ga]MAA: Bmax (44.54), h (0.893). Dual labelling reveals that MAA does not discriminate different radioisotopes. Experiments on pH placed the optimal pH for labelling with 99mTc at 6. Conclusion: Radiolabelling of MAA is possible with high efficiency. The nondiscriminatory MAA bonds make this drug suitable for radiolabelling with different radioisotopes or for dual labelling. This finding illustrates the need to continue investigating MAA chemical and physical characteristics to allow for secure labelling with different isotopes. 相似文献
116.
Marcos Roberto Monteiro Alessandra Regina Pepe Ambrozin Elisangela Fabiana Boffo Luciano Morais Lião 《Talanta》2009,78(3):660-664
In this work, the use of 1H NMR spectroscopy and statistical approach to the evaluation of biodiesel-diesel blends quality is described. Forty-six mixtures of oil-diesel, biodiesel-diesel, and oil-biodiesel-diesel were analyzed by 1H NMR and such data were employed to design four predictive models. Thirty-six mixtures were used in the calibration set and the others in the validation. The PCR and PLS models were evaluated through statistical parameters.Briefly, PLS and PCR models were suitable for the prediction of biodiesel and oil concentration in mineral diesel. Specially, in higher concentration the predicted values were quite similar to the real ones. This fact was evidenced by the low relative errors of high concentrated samples; this means that the prediction of low concentrated samples will probably show high deviation. Therefore, 1H NMR-PLS and 1H NMR-PCR methods are fairly useful for the quality control of biodiesel-diesel blends, particularly they are suitable for prediction of concentrations greater than 2%. 相似文献
117.
Pepe IM Notari L Cugnoli C Panfoli I Morelli A 《Journal of photochemistry and photobiology. B, Biology》2002,66(2):148-152
ATP is synthesized on the disk membrane isolated from rod outer segments of the bovine retina. Together with a slow component which accounted for a constant rate of about 22 nmol ATP/min/mg of protein and which was due to the adenylate kinase activity, a fast component with a maximal activity of about 58 nmol ATP/min/mg of protein was measured at physiological calcium concentrations. This fast activity disappeared in the presence of the Ca(2+) ionophore A23187, was inhibited by vanadate or thapsigargin but not by oligomycin, suggesting that this ATP synthesis is due to the reversal functioning of the Ca(2+)-ATPase previously found on the disk membranes. 相似文献
118.
L.S. Roman R. Valaski E.C.S. Magalhães R. Ahuja I. Pepe 《Applied Surface Science》2006,252(15):5361-5364
Tin oxide (SnO2) is an important oxide for efficient dielectrics, catalysis, sensor devices, electrodes and transparent conducting coating oxide technologies. SnO2 thin film is widely used in glass applications due to its low infra-red heat emissivity. In this work, the SnO2 electronic band-edge structure and optical properties are studied employing a first-principle and fully relativistic full-potential linearized augmented plane wave (FPLAPW) method within the local density approximation (LDA). The optical band-edge absorption α(ω) of intrinsic SnO2 is investigated experimentally by transmission spectroscopy measurements and their roughness in the light of the atomic force microscopy (AFM) measurements. The sample films were prepared by spray pyrolysis deposition method onto glass substrate considering different thickness layers. We found for SnO2 qualitatively good agreement of the calculated optical band-gap energy as well as the optical absorption with the experimental results. 相似文献
119.
Luigi Pepe 《Annali dell'Universita di Ferrara》1978,24(1):191-199
Riassunto Si dimostra la disuguaglianza di Sobolev-Poincaré per una classe generale di domini che intervengono in problemi non uniformemente
ellittici.
Lavoro eseguito nell'ambito dello GNAFA 相似文献
Summary Sobolev-Poincaré inequality for general domains connected with some non uniformly-elliptic problems is proved.
Lavoro eseguito nell'ambito dello GNAFA 相似文献
120.
Abstract— A method for the analytical separation of retinal isomers such as 13- cis , 11- cis , 9- cis and all- trans retinal, dissolved in aqueous solutions of detergents, is described. The retinals are extracted by means of a non-isomerizing procedure and separated by HPLC on an octadecyl silane column used in normal phase. This column retains detergents without deteriorating and gives a satisfactory separation of retinal isomers with a resolution comparable with that obtained with silica gel column. The reliability of the method is verified by analysing the chromophore of visual pigment rhodopsin in digitonin solution, before and after irradiation with white light. 相似文献