Annelise Kopp Alves  Felipe Amorim Berutti  Carlos Pérez Bergmann 《Particulate Science and Technology》2013,31(4):351-360

ABSTRACT

This article describes the effects of pH on the preparation and properties of aluminas (A l ₂ O ₃) produced by the sol-gel colloidal method. The precursor, hexahydrated aluminum chloride, was subjected to peptization reactions giving rise to a viscous gel with amorphous characteristics. Calcination at temperatures about 1000°C caused this gel to transform into alumina products with different morphologies, such as powders, fibers, or porous ceramic bodies, depending on the process parameters adopted, such as the pH and the drying conditions.

These products were characterized according to their particle size distribution, thermogravimetry and differential thermal analysis (TG/DTA), and X-ray diffraction (XRD), and their morphologies were analyzed by scanning electron microscopy (SEM).  相似文献   

    

Laura Chantada  Carlos R. Fernández-pousa  Carlos Gómez-reino 《Journal of Modern Optics》2013,60(4):501-514

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Artur Ciesielski  Carlos‐Andres Palma  Massimo Bonini  Paolo Samorì 《Advanced materials (Deerfield Beach, Fla.)》2010,22(32):3506-3520

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Linda A. Zotti  Thomas Kirchner  Juan‐Carlos Cuevas  Fabian Pauly  Thomas Huhn  Elke Scheer  Artur Erbe 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(14):1529-1535

A combined experimental and theoretical study is presented revealing the influence of metal–molecule coupling on electronic transport through single‐molecule junctions. Transport experiments through tolane molecules attached to gold electrodes via thiol, nitro, and cyano anchoring groups are performed. By fitting the experimental current–voltage characteristics to a single‐level tunneling model, we extract both the position of the molecular orbital closest to the Fermi energy and the strength of the metal–molecule coupling. The values found for these parameters are rationalized with the help of density‐functional‐theory‐based transport calculations. In particular, these calculations show that the anchoring groups determine the junction conductance by controlling not only the strength of the coupling to the metal but also the position of the relevant molecular energy levels.  相似文献   

    

Aparicio FJ  Holgado M  Borras A  Blaszczyk-Lezak I  Griol A  Barrios CA  Casquel R  Sanza FJ  Sohlström H  Antelius M  González-Elipe AR  Barranco A 《Advanced materials (Deerfield Beach, Fla.)》2011,23(6):761-765

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Jan Paca  Eva Klapkova  Martin Halecky  Kim Jones  Carlos Riccardo Soccol 《Clean Technologies and Environmental Policy》2007,9(1):69-74

The removal of a mixture of painting solvents from waste air using a biofiltration process was evaluated in this project. The pollutants removed included hydrophobic (aromatic hydrocarbons) and hydrophilic (water soluble ketones and esters) compounds. A trickle bed reactor with a defined immobilized mixed culture on polyethylene Pall rings was utilized in this biodegradation study. The removal efficiencies (RE) of the individual groups of pollutants during loading experiments were determined. An increase of the aromatic hydrocarbons loading resulted in a drop of their RE_AROM with no effect on the RE value of ketones. The overloading of ketones caused a rapid drop in RE_AROM and a small drop in RE_KET. To achieve a restoration of the biocatalyst degradation properties after the increase in loading, an addition of phosphate to the aqueous medium was implemented which successfully restored the removal efficiency.  相似文献   

    

Hajo J. A. Molegraaf  Jason Hoffman  Carlos A. F. Vaz  Stefano Gariglio  Dirk van der Marel  Charles H. Ahn  Jean‐Marc Triscone 《Advanced materials (Deerfield Beach, Fla.)》2009,21(34):3470-3474

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Raimundo Carlos Silverio Freire  Adrião Duarte Dória Neto  Eve Maria Freire De Aquino 《International Journal of Fatigue》2009,31(5):831-839

The purpose of this paper is to assess the applicability of two artificial neural networks (ANN) architecture, perceptron ANN, modular ANN, and Adam’s equation in the modeling of fatigue failure in polymer composites, more specifically in glass fiber reinforced plastic (GFRP). In the application of the model using ANN we show the feasibility of obtaining good results with a small number of S–N curves. The other model used involves applying empirical equations known as Adam’s equations. A comparative study on the application of the aforementioned models is developed based on statistical tools such as correlation coefficient and mean square error. For this analysis we used composite materials in the form of laminar structures with distinct stacking sequences, which are applied industrially in the construction of large reservoirs. Reinforcements consist of mats and bidirectional textile fabric made of E-glass fibers soaked in unsaturated orthophthalic polyester resin. These were tested for six different stress ratios: R = 1.43, 10, ?1.57, ?1, 0.1, and 0.7. The results showed that although ANN modeling is in the initial phase, it has great application potential.  相似文献   

    

Carlos J. S. Alves  Pedro R. S. Antunes 《International journal for numerical methods in engineering》2009,77(2):177-194

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Annamaria Petrozza  Sergio Brovelli  Jasper J. Michels  Harry L. Anderson  Richard H. Friend  Carlos Silva  Franco Cacialli 《Advanced materials (Deerfield Beach, Fla.)》2008,20(17):3218-3223

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