Neutral vanadium, niobium, and tantalum oxide clusters are studied by single photon ionization employing a 26.5 eV/photon soft x-ray laser. During the ionization process the metal oxide clusters are almost free of fragmentation. The most stable neutral clusters of vanadium, niobium, and tantalum oxides are of the general form (MO2)0,1(M2O5)y. M2O5 is identified as a basic building unit for thes...

PURPOSE This study evaluated the stability and histologic proof of osseoincorporation of Trabecular Metal (TM) dental implants, which feature a tantalum-based porous midsection. MATERIALS AND METHODS A total of 48 TM implants (test group) and Tapered Screw-Vent implants (control group) were immediately placed bilaterally into mandibular extraction sockets in dogs. Resonance frequency analysis...

TiO2 (band gap = 3.0 eV) and SrTiO3 (band gap = 3.2 eV) codoped with nickel and either tantalum or niobium ions showed photocatalytic activities for O2 evolution from an aqueous silver nitrate solution and H2 evolution from an aqueous methanol solution under visible light irradiation (lambda > 420 nm). The visible-light responses were due to the charge-transfer transition from the electron dono...

We predict that modified thermal emission can result from three-dimensional, self-assembled photonic crystals. In previous tungsten structures, known as inverse opals, strong absorption prevented any influence of the periodicity. We consider the origin of this effect and show how to tailor both absorption and surface coupling in experimentally realizable metallic inverse opals. Calculations for...

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BioAggregate is a new product that was formulated for root-end filling, perforation repair, and pulp capping. This study examined the chemical differences between white mineral trioxide aggregate (MTA) and BioAggregate in both powder and set forms using X-ray diffraction. The results showed that white MTA and BioAggregate have a similar chemical composition with some differences: BioAggregate c...

The title compounds were synthesized by reaction of the elements in sealed tantalum tubes in a water-cooled sample chamber in a high-frequency furnace. These magnesium intermetallics crystallize with the tetragonal Mo2FeB2 type structure, space group PMmbm. The lattice pa­ rameters of all compounds were refined from X-ray powder data. Single crystal X-ray data yielded a = 792.09(6), c = 396.31(...

Molybdenum disulfide coatings have been employed as lubricants for spacecraft since the 1950s but continue to face major engineering challenges including performance in both terrestrial air and deep space vacuum environments service lifetimes on order of decades without maintenance. Co-deposition MoS2 with additive compounds provide enhancements some circumstances a lubricant which can perform ...

First principles total energy calculations were performed in order to characterize O vacancy defects in Ta O . A simplified 2 5 version of the crystalline orthorhombic phase of Ta O was used in this study. Results indicate that O vacancies in Ta O 2 5 2 5 can be broadly classified based on their location in the lattice. One type of vacancy (occupying the ‘in-plane’ sites) displays deep or mid g...