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Aluminium Oxide (aluminium + oxide)
Selected AbstractsA micron-sized nanoporous multifunction sensing devicePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2009L. Moreno i Codinachs Abstract In this work, a capacitive sensor based on Anodic Aluminium Oxide (AAO) porous structures has been developed. In some cases, the pores have been also conformally coated with a high chemical pure SiO2 by means of Atomic Layer Deposition (ALD). Temperature measurements have been done in DI water obtaining a response of 5 nF/°C. pH measurements have been performed and the responses obtained are between 0.2 and 1 nF/pH. The reproducibility of the sensors has been found to be high and a larger hysteresis effect has been observed in the samples with alumina pores rather than in the SiO2 ones. The hysteresis seems to be related to the charging of the oxide upon application of a voltage. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ion Energy Distributions in Magnetron Sputtering of Zinc Aluminium OxidePLASMA PROCESSES AND POLYMERS, Issue S1 2009Thomas Welzel Abstract Ion energy distributions have been measured with an energy-dispersive mass spectrometer during magnetron sputtering of Al doped ZnO. A d.c. and a pulsed d.c. discharge have been investigated. Different positive ions from the target material have been observed with low energies in d.c. and a second energy peak of about 30 eV in pulsed d.c. with only weak additional energy due to the sputter process. Negative ions are mainly O, with energies corresponding to the target voltage of several 100 eV. They originate from the target and barely from the (O2) gas and hit the substrate opposite the race track. In pulsed d.c., due to the varying target voltage, energies of up to 500 eV have been observed. With increasing pressure, negative ions at the substrate are reduced exponentially in their density but not in their energy. [source] High-Density Periodically Ordered Magnetic Cobalt Ferrite Nanodot Arrays by Template-Assisted Pulsed Laser DepositionADVANCED FUNCTIONAL MATERIALS, Issue 21 2009Xingsen Gao Abstract A novel nanopatterning method using pulsed laser deposition through an ultrathin anodic aluminium oxide (AAO) membrane mask is proposed to synthesize well-ordered nanodot arrays of magnetic CoFe2O4 that feature a wide range of applications like sensors, drug delivery, and data storage. This technique allows the adjustment of the array dimension from ,35 to ,300,nm in diameter and ,65 to ,500,nm in inter-dot distance. The dot density can be as high as 0.21 Terabit in.,2. The microstructure of the nanodots is characterized by SEM, TEM, and XRD and their magnetic properties are confirmed by well-defined magnetic force microscopy contrasts and by hysteresis loops recorded by a superconducting quantum interference device. Moreover, the high stability of the AAO mask enables the epitaxial growth of nanodots at a temperature as high as 550,°C. The epitaxial dots demonstrate unique complex magnetic domains such as bubble and stripe domains, which are switchable by external magnetic fields. This patterning method creates opportunities for studying novel physics in oxide nanomagnets and may find applications in spintronic devices. [source] Heterogeneous Palladium Catalysts for a New One-Pot Chemical Route in the Synthesis of Fragrances Based on the Heck ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2007Maria Jose Climent Abstract The one-pot synthesis of the fragrance 4-(p -methoxyphenyl)butan-2-one, with raspberry scent, has been carried out using palladium on different supports such as magnesium oxide (MgO), hydrotalcite, hydroxyapatite (HA), aluminium oxide (,-Al2O3) and titanium dioxide (TiO2). The first pathway consists of a Heck coupling between 4-methoxyiodoanisole and methyl vinyl ketone followed by hydrogenation. Palladium supported on titanium dioxide showed the best performance for carrying out both consecutive steps giving 4-(p -methoxyphenyl)butan-2-one with high yields and selectivity. The Pd-TiO2 catalyst is more active than a homogeneous palladium complex that is well accepted in the literature as being highly active for performing Heck reactions. [source] Static SIMS studies of the oxides and hydroxides of aluminiumJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2007S. Verdier Abstract The degree of hydroxylation or hydration of aluminium surfaces has been examined by static secondary ion mass spectroscopy (SSIMS). The SSIMS spectra of a series of aluminium oxide, oxyhydroxide and hydroxide surfaces have been obtained using instruments in three configurations. Similarities were observed in both negative and positive secondary ions spectra. Even though a direct comparison of the relative intensities cannot be made from one instrument to the other, a similar ranking of the various aluminium hydroxylation states was observed. Several ranking methods are discussed, as well as the similarities and differences observed while using the three instruments. Similar secondary ions were detected whatever the degree of hydroxylation of the aluminium oxide. This argues in favour of the formation of fragments by the combination of individually sputtered atoms or clusters to form the more stable secondaries, rather than the kick-off of ,structure-related' clusters originating directly from the upper surface layer. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||