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Chantal Paquet

Publications and source records attributed to Chantal Paquet.

4 recordsLinked to original sources

Guest-host colloid crystals: experimental study and simulations.

Disorder in colloid crystals was induced by doping them with a different number of large or small guest particles, which had a different deviation in size from the host colloids. The change in optical properties of the guest-host colloid crystals was assessed by using optical transmission spectroscopy while the variation in crystal structure was examined using scanning electron microscopy (SEM). The disruption in the crystalline lattices depended on the relative deviation in sizes of the guest and host particles and the concentration of the guest colloids. In parallel with experiments, the packing of spheres in guest-host crystals was modeled with a simulated annealing algorithm. A good correlation was found between the changes in crystal structure observed by SEM imaging and the simulated sphere packing. The experimental and simulated changes in the transmission spectra of guest-host colloid crystals were in good agreement.

Journal Article↗

Size-selected synthesis of PtRu nano-catalysts: reaction and size control mechanism.

A rapid synthesis method for the preparation of PtRu colloids and their subsequent deposition on high surface area carbons is presented. The reaction mechanism is shown to involve the oxidation of the solvent, ethylene glycol, to mainly glycolic acid or, depending on the pH, its anion, glycolate, while the Pt(+IV) and Ru(+III) precursor salts are reduced. Glycolate acts as a stabilizer for the PtRu colloids and the glycolate concentration, and hence the size of the resulting noble metal colloids is controlled via the pH of the synthesis solution. Carbon-supported PtRu catalysts of controlled size can be prepared within the range of 0.7-4 nm. Slow scan X-ray diffraction and high-resolution transmission electron microscopy show the PtRu catalysts to be crystalline. The Ru is partly dissolved in the face-centered cubic Pt lattice, but the catalysts also consist of a separate, hexagonal Ru phase. The PtRu catalysts appear to be of the same composition independent of the catalyst size in the range of 1.2-4 nm. Particular PtRu catalysts prepared in this work display enhanced activities for the CH(3)OH electro-oxidation reaction when compared to two commercial catalysts.

Journal Article↗

Quantitation of film coating on Zantac 75 mg tablets and Epivir HBV 100 mg tablets by ICP-AES.

PURPOSE: To present a selective analytical Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) method developed and validated for the quantitation of tablet film coatings containing titanium. METHODS: Tablet samples were decomposed by either digestion or dry ashing. The amount of film tablet coating was calculated based on titanium content of the sample. RESULTS: The reported ICP-AES method was accurate, precise, sensitive and linear for determination of titanium concentrations from 2.9 to 8.6 ppm. CONCLUSION: This method provides an accurate determination of the amount of coating on a tablet and has general applicability for a variety of coating formulations containing different elements.

Anti-HIV Agents↗