Materials Literature
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This review describes the mechanisms responsible for low-temperature degradation (LTD) of zirconia ceramics and its detrimental consequences for biomedical devices. Special emphasis is given to the critical issue of zirconia degradation actually observed for hip prostheses. Experimental methods to accurately measure a…
Predictions and measurements of the effect of biaxial strain on the properties of epitaxial ferroelectric thin films and superlattices are reviewed. Results for single-layer ferroelectric films of biaxially strained SrTiO 3 , BaTiO 3 , and PbTiO 3 as well as PbTiO 3 /SrTiO 3 and BaTiO 3 /SrTiO 3 superlattices are desc…
Crystal and magnetic structure analyses have been performed for single crystals of multiferroic materials R Mn 2 O 5 ( R = Y, Ho, Er) using the neutron diffraction technique. For all the compounds, the magnetic structure in the commensurate magnetic phase, where spontaneous electric polarization occurs, was determined…
Recent experiments (F.H.J. Van Der Heyden et al., PRL 96, 224502 (2006)) of streaming currents in silica nanochannels with divalent ions report charge inversion, i.e. interfacial charges attracting counterions in excess of their own nominal charge, in conflict with existing theoretical and simulation results. We revea…
Silica type nanostructured hybrid materials have been prepared by co-assembly of sol−gel materials and an extended amphiphilic dendron consisting of a hydrophilic aliphatic polyether block and hydrophobic docosyl chains. As confirmed by small- and wide-angle X-ray scattering (SAXS and WAXS) experiments, the hybrid pre…
Tubular graphite cones (TGCs) with a single-crystal nanotip have been achieved by means of microwave plasma-assisted chemical vapor deposition using in-situ-evaporated Fe catalysts. The absence of the disorder-induced D band in Raman spectra revealed the single-crystalline feature of the nanotip. TGCs were found to st…
Metal nanoparticles (NPs) are used to catalyze the formation of molecular multielectron transfer products, for example, H 2, from single-electron reductants, such as radicals. Noble metals, like silver and gold, were very instrumental in unraveling the mechanism of this interfacial process. In this study, we explore t…
The relative probability of two- and three-photon absorption in Au nanoparticles was adjusted by tuning the surface-plasmon-resonance (SPR) wavelength and the excitation intensity. Consequently, highly efficient three-photon luminescence from Au nanoparticles with strong SPR enhancement was observed. The decay rate an…
Abstract We report a one-pot preparation method for a series of novel shaped gold microcrystals by simply mixing HAuCl4 with disodium salt of ethylenediaminetetraacetic acid (Na2EDTA). Under the different reaction temperatures, spinous structures, multipod microspheres, and rough surfaced microspheres were obtained. T…
Optically active poly(1,4-di(2-thienyl)phenylene), poly(terthiophene), poly(bithiophene), and poly(2,5-di(2-thienyl)pyridine) are successfully prepared by asymmetric electrochemical polymerization in a cholesteric electrolyte. The polymers thus synthesized are confirmed by polarizing optical microscopy to assume the d…
Aculeacin A acylase from Actinoplanes utahensis produced by Streptomyces lividans revealed acylase activities that are able to hydrolyze penicillin V and several natural aliphatic penicillins. Penicillin K was the best substrate, showing a catalytic efficiency of 34.79 mM(-1) s(-1). Furthermore, aculeacin A acylase wa…
The present work reports the tracer diffusion coefficient for (93)Nb in rutile TiO(2) single crystals using secondary ion mass spectrometry (SIMS). The determined tracer diffusion coefficient exhibited the following temperature dependence in air ( p(O2) = 21 kPa) over the range 1073-1573 K: D93(Nb) = (4.7 m2 s(-1))x10…
Phase separation driven by a reversible photo-cross-linking reaction was investigated by using anthracene-labeled polystyrene/poly(vinyl methyl ether) (PSA/PVME) blends. Upon irradiation with 365 nm ultraviolet light, anthracene moieties undergo photodimerization, leading to phase separation of the two polymers. On th…
The present work was aimed at characterizing the acoustic emission (AE) response of α-brass during SCC propagation. For that purpose, slow strain rate tensile tests (SSRT) under potentiostatic control were performed in a 1 M NaNO2 solution and in Mattsson’s solution. The differences between the AE signals generated by…
Polyphosphazenes are a class of hybrid organic-inorganic macromolecules with high thermo-oxidative stability and good solubility in many solvents. Fluoroalkoxy phosphazene polymers also have high surface hydrophobicity. A method is described to tune this surface property while maintaining the advantageous bulk materia…
In this paper we report the results of polarization resolved hyper-Rayleigh scattering measurements of copper nanoparticles of 5−55 nm size. The polar plot of polarization-resolved second harmonic intensity against polarization angle from the copper nanoparticles resembles the pattern seen from a dipolar source. The m…
Two lacto-N-biose phosphorylase (LNBP) isozyme genes were cloned from Bifidobacterium bifidum JCM1254. Alignment of the amino acid sequences of LNBP and its homologs identified 24 completely conserved acidic amino acid residues. All single mutants of Bifidobacterium longum LNBP at residues other than D313N retained co…
9,10-Dichlorooctafluoroanthracene (1) was synthesized from commercially available tetrafluorophthalic acid by an optimized solution-phase route. To establish 1 as a synthon for n-type organic semiconductors, the compound was reacted with phenylboronic acid under modified Suzuki-Miyaura coupling conditions to generate…
The electronic structure of bis(thiocyanato)gold(I) complexes is studied both experimentally and theoretically. Temperature-dependent photoluminescence studies for K[Au(SCN) 2 ] reveal two unstructured luminescence bands: a strong green phosphorescence band (τ 77K = 45.4 μs) and a weak blue fluorescence band (τ 77K =…
The surface energy of β-tetragonal (β-t) boron has been calculated from first principles to investigate how it affects nanoscale crystal growth. The results show that the surface energy of β-t boron is higher than that of α-tetragonal (α-t) boron, and lower than that of α-rhombohedral (α-rh) and β-rhombohedral (β-rh)…