Paulo J. Ferreira

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Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a(More)
Rotating disk electrode measurements of acid-treated " Pt 3 Co " nanoparticles showed specific oxygen reduction reaction (ORR) activity (∼0.7 mA/cm Pt 2 at 0.9 V vs RHE in 0.1 M HClO 4 at room temperature), twice that of Pt nanoparticles. Upon annealing at 1000 K in vacuum, the ORR activity at 0.9 V was increased to ∼1.4 mA/cm Pt 2 (four times that of Pt(More)
  • Mikhail S Saraiva, José A F Gamelas, António P Mendes De Sousa, Bruno M Reis, José L Amaral, Paulo J Ferreira
  • 2010
A new approach for the chemical modification of the surface of paper based on the application of colloidal mixtures containing cationic starch and polyoxometalates on uncoated base paper is presented. Polyoxometalates with the Keggin-type structure and physical properties similar to those presented by coating pigments, namely O, have been used in order to(More)
This paper presents a system for 3D ultrasound which aims to reconstruct a volume of interest from a set of ultrasound images. A Bayesian reconstruction algorithm has been recently proposed to perform this task. However, it is too slow to be useful in practice. This paper describes several techniques to improve the efficiency of the reconstruction procedure(More)
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