Evolution Of Silicates Research Articles

Preparation and Characterization of Silane-Stabilized, Highly Uniform, Nanobimetallic Pt−Pd Particles in Solid and Liquid Matrixes

Highly uniform, stable nanobimetallic dispersions are prepared in a single step in the form of sols, gels, and monoliths, using organically modified silicates as the matrix and the stabilizer. The Pt−Pd bimetallic dispersions are characterized by UV−vis, TEM, SEM, and XRD measurements. The evolution of silicate was followed by IR spectroscopy. XPS and CO adsorption studies reveal that the structure of the particles consists of a palladium core and a platinum shell. Electrocatalysis of ascorbic acid oxidation has been demonstrated using thin films of silicate containing the nanobimetal particles on a glassy carbon electrode.

The accretion of interplanetary dust by AP and AM stars

view Abstract Citations (11) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Accretion of Interplanetary Dust by AP and AM Stars Kumar, C. Krishna ; Davila, Joseph M. ; Rajan, R. Sundar Abstract Accretion of interplanetary dust and comets by A-type stars is investigated to see whether this process can explain the overabundances of heavy elements in Ap and Am stars. The dust particles spiral in by the Poynting-Robertson effect and evaporate above the star. This process is evaluated by considering the evolution of silicate and graphite particles in the radiation field of Alpha Leo (B7 V). It is found that graphite particles evaporate above 20 stellar radii and silicate dust grains above 50 stellar radii. The evaporated atoms will be quickly ionized. In the case of Am stars the ions will wander off and not reach the photosphere, but in the case of Ap stars they can be trapped by the magnetic field of the star and reach the surface. The magnetosphere of a typical Ap star is modeled, and the fate of the ions is studied. The efficiency of accretion from the magnetosphere is sensitive to the presence of any plasma in the magnetosphere. The comet impact process is found capable of producing the abundance anomalies in Ap as well as Am stars, assuming that the comet impact rate is 0.03/yr, nearly the same as in the solar system. Publication: The Astrophysical Journal Pub Date: February 1989 DOI: 10.1086/167112 Bibcode: 1989ApJ...337..414K Keywords: A Stars; Interplanetary Dust; Interstellar Matter; Peculiar Stars; Stellar Mass Accretion; Comets; Evaporation; Graphite; Magnetospheres; Metallic Stars; Photosphere; Astrophysics; INTERSTELLAR: GRAINS; INTERPLANETARY MEDIUM; STARS: ACCRETION; STARS: METALLIC-LINE; STARS: PECULIAR A full text sources ADS | data products SIMBAD (3)