Materials Literature
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The local, temperature dependent structure of poly-(ethylmethacrylate) was studied with wide-angle x-ray scattering. The results were set into context to recent wide-angle neutron scattering results as well as to the results from a multitude of studies of the dynamics of this polymer. The temperature dependence of the…
Owing to the positively charged grain boundary cores in acceptor-doped and oxygen vacancies are depleted in the space charge layers. The validity of this space charge concept was checked for -doped ceramic of high purity. Electrical fields up to were applied to the grain boundaries of 1.0 mol % -doped at 400°C in air,…
Cu-Co bimetallic mixtures with ceria and YSZ have been investigated as solid oxide fuel cell (SOFC) anodes. While pure Co is unstable in dry CH 4 at 1073 K due to severe carbon formation, Cu-Co mixtures with even 90 wt % Co showed only small amounts of carbon following exposure to dry CH 4 for 2 h at 1073 K. Cells bas…
Abstract Ultrasound medical applications, such as an ultrasound imaging with micro‐bubble contrast agents, and high intensity focused ultrasound (HIFU) therapy have attracted much attention in recent years. These applications have a close relation to the motion of micro‐bubbles, so that it is essential to understand t…
An analytical description of polymer melts and their mixtures as liquids of interacting soft colloidal particles is obtained from liquid-state theory. The derived center-of-mass pair correlation functions with no adjustable parameters reproduce those computed from united atom molecular dynamics simulations. The coarse…
We investigate the structures and magnetic properties of small Mn(n) clusters in the size range of 2-13 atoms using first-principles density functional theory. We arrive at the lowest energy structures for clusters in this size range by simultaneously optimizing the cluster geometries, total spins, and relative orient…
Nanostructured ZnFe 2 O 4 and zinc oxide−iron oxide composites were obtained by sol−gel processing of a hetero-bimetallic alkoxide. For this purpose the novel molecular precursors Fe 2 Zn(OR) 8 (R = t Bu, i Pr), fully characterized by spectroscopic and single-crystal diffraction techniques, have been synthesized and t…
This article reviews the most recent progress in the synthesis of polar-surface dominated semiconducting and piezoelectric ZnO nanostructures: including nanosprings, nanohelices, nanorings, nanobows and nanodisks. These structures were formed by self-assembly of polar nanobelts/nanowires as driven by minimizing electr…
Abstract A recently developed method to determine the energy levels of divalent lanthanide ions relative to the conduction band and valence band of host compounds is applied to Sr 2 MgSi 2 O 7 doped with Eu 2+ and Dy 3+ . The level locations are not consistent with the widely adopted and generally believed mechanism o…
The physical properties, crystallization, and spherulite growth behavior and mechanism of linear and 3-arm poly(L-lactide) [i.e., poly(L-lactic acid) (PLLA)] have been investigated using absolute molecular weight as a molecular index. The branching reduces the chain mobility of PLLA and must be excluded from the cryst…
Sandwich-type all-MgB2 Josephson tunnel junctions (MgB2/AlOx/MgB2) have been fabricated for the first time with as-grown MgB2 films formed by molecular beam epitaxy. The junctions exhibit substantial superconducting current (IcRN product ~ 0.8 mV at 4.2K), a well-defined superconducting gap (delta = ~2.3 mV), and clea…
The underlying mechanism of the metal-to-insulator transition (MIT) in BaVS$_3$ is investigated, using dynamical mean-field theory in combination with density functional theory. It is shown that correlation effects are responsible for a strong charge redistribution, which lowers the occupancy of the broader \a1g band…
Mn-doped ZnO multileg nanostructures were synthesized via in situ thermal oxidation of Zn and MnO2 powder. Spectroscopic measurements show that Mn ions have been doped into the lattice positions of Zn ions, which strongly induce growth of the observed ZnO multileg nanostructure. It is revealed that the growth mechanis…
We show that the theory of spin-phonon processes in paramagnetic solids must take into account the coherent generation of phonons by the magnetic centers. This effect should drastically enhance spin-phonon rates in nanoscale paramagnets and in crystals of molecular nanomagnets.
Although as-grown carbon nanotubes have relatively few defects, defects can appear at the purification stage or be deliberately introduced by irradiation with energetic particles or by chemical treatment when aiming at the desired functionality. The defects, especially vacancies, give also rise to a deleterious effect…
A trinuclear Au(I) pyrazolate complex bearing long alkyl chains (1) in hexane self-assembles via a Au(I)-Au(I) metallophilic interaction, to form a red-luminescent organogel (lambda(em) = 640 nm, lambda(ext) = 284 nm). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis of an air-dried gel with 1 s…
The effects of charge density on weak polyelectrolyte multilayer growth were investigated by assembling several strong polyelectrolytes with either poly(allylamine hydrochloride) (PAH) or poly(acrylic acid) (PAA) to keep one polymer fully charged while varying the degree of ionization of the other. The degree of ioniz…
Methyl group dynamics of m-xylene was investigated by using incoherent inelastic and quasi-elastic neutron scattering. Inelastic measurements were carried out at the high flux backscattering spectrometer HFBS at the National Institute of Standards, quasi-elastic measurements at the time-of-flight spectrometer NEAT at…
Abstract Using a test method developed at the high‐voltage laboratory of the NSERC/Hydro‐Quebec/UQAC Industrial Chair on Atmospheric Icing of Power Network Equipment (CIGELE), the relation between the minimum flashover voltage V MF and the insulator dry arcing distance for standard porcelain station post insulators, a…
The adsorption and decomposition of NO have been investigated by using density functional theory method at the generalized gradient approximation level. We have performed calculations on adsorption energies and structures of NO on Ni(211) and Pd(211) surfaces with full-geometry optimization and compared them with the…