A first-principles study of the vibrational modes of PbTiO3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone ~BZ!. The calculations use the local-density approximation and ultrasoft pseudopotentials with a plane-wave basis, and reproduce well the available experimental information on the modes at the G point, including the LO-TO spli...

Résumé. La reconnaissance de l'écriture arabe manuscrite est un domaine de recherche relativement récent et qui a connu ces dernières années des progrès remarquables. Il présente un intérêt indéniable dans l’accomplissement de tâches considérées fastidieuses dans certains domaines comme le tri postal, la lecture de chèques bancaires, la lecture des bordereaux, etc. Ce papier présente la concept...

Carl Gustav Hempel 's (19051997) classic account of explanation is widely known as the "cover ing-law model. " It includ es two species : the Deductive-Nomological Expla nation and the Probabilistic-Statist ical Explanation . Since its introduction in the semi nal pape r co-authored by Hempel and Paul Oppenheim (1948), the model has been intense ly debated and criticized in the philosophy of sc...

Combined in situ X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) studies have been conducted to follow gold structural changes of low-content (<1%Au) gold-ceria catalysts in water-gas shift (WGS) reaction tests at 100 and 200 °C; and after heating the used catalysts in oxygen gas at 150 °C. Gold in the fresh (400 °C-calcined) material was atomic...

Activated carbon is loaded with 2 totally different metals: Ce and iron. The catalyst was characterised by Brunauer Emmett Teller (BET) Fourier rework Infrared (FTIR). discharged conditioner had the best area pore volume of 1100 m2/g 0.3 cm3/g, respectively.AC/Ce/Fe achieved kerosene adsorption performance (75%) though lowest surface 965.7608 0.39 cm3/g due to acidic sites required for sulfur c...

Aqueous biphasic catalysis is a convenient approach to convert organic, partially soluble molecules in water. However, converting more hydrophobic substrates is much more challenging as their solubility in water is extremely low. During the past ten years, substantial progress has been made towards improving the contact between hydrophobic substrates and a hydrophilic transition-metal catalyst....

This paper argues that Information Technology (IT) needs to be demystified, through critical consciousness, for educators to focus on IT as a means to enhance learning. It goes on to define the technical, sociohistorical and political-ideological levels of IT and to identify four theoretical constructs: tutorial, machine-as-human, tool kit and catalyst. Pervading these constructs is the underst...

The catalytic oxidation of VOCs is widely acknowledged as the most available technology to reduce air pollution. Among catalysts for VOCs, 1 wt%-Pt/TiO2 using metal a doping element have shown amazing potential in many fields. However, achieving high performance at relatively low temperatures based on activation molecules still formidable challenge owing activity being highly dependent temperat...

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RÉSUMÉ. Cet article présente une approche sociale pour la recherche d’information dans les microblogs intégrant diverses sources d’évidence au sein d’un réseau bayésien. Notre contribution consiste à étendre la notion classique de pertinence, basée sur la similarité textuelle, par de nouveaux facteurs tels que l’importance sociale des blogueurs et la magnitude temporelle des microblogs. Dans ce...