Owing to intrinsic scientific interest and its immense importance in catalysis technology, the oxidation of carbon monoxide has attracted much attention in the past few decades. The reaction is effectively catalyzed by certain noble metals, such as gold, platinum, palladium, and rhodium. Among all of these metals, gold exhibits an extraordinarily high activity because CO molecules adsorb strong...

Age-hardening characteristics in a dental low-gold alloy composed of 40.0 wt% Au-35.0 wt% Ag-7.9 wt% Pd-7.0 wt% Cu-5.0 wt% In-3.5 wt% Zn-1.5 wt% Sn, were investigated by means of the hardness test, XRD study, SEM observations and EPMA. The following results were obtained. The age-hardening was characterized by a precipitation of Cu-rich alpha2 phase in the a phase. The softening that occurred f...

Orthodontic mechanotherapy encompasses the use of several archwires during speci c stages of treatment. Metallic orthodontic appliances consist of bands, arch wires, ligature wires, hooks, tubes, brackets, and springs are daily used in orthodontic practices for the correction of malocclusions in patients ( Oh et al. , 2004 ; Verstrynge et al. , 2006 ; Sabane et al. , 2009 ). One of the most im...

AIMS The aims of this study were to investigate the influence of commercially pure titanium (PTi) and titanium-aluminum-vanadium (Ti-6Al-4V) alloys (TiA) on the final shade of low-fusing porcelain bonded to them and to compare the shade changes with those of three conventional metal-ceramic systems. METHODS AND MATERIALS A titanium casting unit was used to cast PTi and Ti-6Al-4V alloy specime...

PURPOSE The maximum preload torque of implant prosthetic retaining screws from four manufacturers and of two alloy types was measured to determine one index of interchangeability of intersystem components. MATERIALS AND METHODS Implant prosthetic retaining screws from four manufacturers (3i Implant Innovations Inc, West Palm Beach, FL; Impla-Med Inc, Sunrise, FL; Nobelpharma USA Inc, Chicago,...

Monolayer-protected Au, Ag, and Au:Ag alloy nanoclusters have been synthesized using octanethiol and octadecanethiol as capping agents. The particle-size distribution is narrow with an average core size of 3–4 nm. Optical nonlinearity induced by 35 ps pulses at 532 nm has been investigated in these samples using the Z-scan technique. It is found that in general, they behave either as saturable ...

The adsorption of ethylene on gold–palladium alloys formed on a Pd(111) surface is investigated using a combination of temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS). Various alloy compositions are obtained by depositing four monolayers of gold on a clean Pd(111) surface and annealing to various temperatures. For gold coverages greater than 0.7, ...