Materials Literature
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Thermodynamic properties of $\mathrm{Ca}\mathrm{W}{\mathrm{O}}_{4}$ were studied using the GULP code incorporating semiclassical simulations based on quasiharmonic lattice dynamics and static lattice minimisation methods. Free energy minimization along with so called ``relax'' fitting was used to obtain the parameters…
Partial discharge (PD) degradation was investigated to compare polyamide nanocomposites with two kinds of polyamide microcomposites. Such materials were exposed to PDs under the IEC(b) electrode configuration for evaluation of PD resistance. Comparisons were made as to the surface roughness using a scanning electron m…
A series of O18 tracer in-diffusion experiments have been conducted on state-of-the-art metal organic chemical vapor deposition–grown Pb(Zr,Ti)O3 (PZT) films. Prior to O18 incorporation, samples were preequilibrated in O216 at the same temperature and total pressure used for the following O218 isotope exchange anneal.…
A study of Fe-ZSM-5 catalysts with variable amounts of isolated, oligomeric and heavily aggregated Fe3+ oxo sites (as evidenced by UV-Vis and EPR spectroscopic data) and their catalytic properties in the selective catalytic reduction of NO by isobutane or by NH3 is presented, which allows development of a unified conc…
Ferromagnetic resonance (FMR) and ac conductivity have been applied to study a polymer composite containing as filler a binary mixture of magnetite (Fe3O4) and cementite (Fe3C) nanoparticles (30–50nm) dispersed in a diamagnetic carbon matrix, which was synthesized by the carburization of nanocrystalline iron. Ac condu…
It has been demonstrated that the electrical breakdown properties of polymer composites can be substantially enhanced when the filler particles are of nanometric dimensions. These benefits are likely related to the mitigation and redistribution of internal charge. Using the example of an epoxy-TiO/sub 2/ nanodielectri…
In the study, various amounts of nano- and micro-scale zinc oxide particles (62 nm and 1 /spl mu/m average diameter) were systematically introduced into an Araldite epoxy resin matrix for reinforcement purposes. The influence of these particles on the electrical treeing breakdown resistance was investigated experiment…
Porous and nonporous metallic Ag nanostructures were fabricated with ease by using cellulose fiber as a template.
The air oxidation kinetics of low coverages of ∼5nm Si nanoparticles, deposited by pulsed excimer laser ablation (KrF, 248 nm) in He, have been characterized by x-ray photoelectron spectroscopy. A simple model, based on the evolution of the Si 2p spectral components during oxidation, has been developed to determine th…
Detailed phonon scattering at an ideal Si–Ge interface is studied with a linear lattice dynamics model. Frequency dependent transmission coefficients indicate the significance of acoustic-optical phonon mode conversion at the interface. Applied to multiple interfaces, the method shows how the overall thermal resistanc…
This work presents results of dielectric spectroscopy and space charge (PEA) measurements on epoxy resin filled with 10% w/w micro- and nano- sized particles of TiO/sub 2/, Al/sub 3/O/sub 2/ and ZnO. The results appear to show that the material from which the nano-particle is made is not highly significant in influenc…
The Aurivillius family includes many compounds with ferroelectric phases. Despite sharing the basic perovskite structural block with more common ferroelectric oxides such as $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_{3}$ or $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$, their phase-transition behavior is rather more complex. In…
Manganese and cobalt-doped ZnO have been produced using a modified melt-growth technique. X-ray diffraction measurements indicate that the samples are high-quality single crystals with ω−2θ full width at half maximum values of 78 arc sec for the undoped ZnO and 252 arc sec for Zn1−xMnxO (x=0.05). The lattice parameter…
Spontaneous one dimensional arrangements of spherical Au nanoparticles were accomplished by using a liquid crystalline thiol ligand, 4'-(12-mercaptododecyloxy)biphenyl-4-carbonitrile. Simple thermal treatment of Au nanoparticles with the ligands showed 1D ordering of the Au nanoparticles.
Synergistic multivalent interactions can amplify desired chemical or biological molecular recognitions. We report a new class of multicarboxylate-containing carbocyanine dye constructs for use as optical scaffolds that not only serve as fluorescent antennas but also participate in structural assembly of the multivalen…
Based on density-functional perturbation theory we have computed the photoelastic tensor of a model of sodium silicate glass of composition ${({\mathrm{Na}}_{2}\mathrm{O})}_{0.25}{(\mathrm{Si}{\mathrm{O}}_{2})}_{0.75}$ (NS3). The model (containing 84 atoms) is obtained by quenching from the melt in combined classical…
the intrinsically glycopeptide-resistant Enterococcus gallinarum, Enterococcus casseliflavus, and Enterococcus flavescens (VanC type) and is present in the VanE and VanG types in which E. faecalis has acquired the genes encoding vancomycin resistance. Some of the enzymes implicated in this second resistance mechanism…
Raman scattering experiments have been performed on Na_xCoO_2 as function of temperature at the composition x=0.5 where a structural instability and a metal-insulator transition have been observed. Three additional phonon modes are observed compared to samples with larger x. An in-situ annealing study (T_max=550 K) wi…
The pseudobond approach offers a smooth connection at the quantum mechanical/molecular mechanical interface which passes through covalent bonds. It replaces the boundary atom of the environment part with a seven-valence-electron atom to form a pseudobond with the boundary atom of the active part [Y. Zhang, T. S. Lee,…
A new type of hierarchical structure, a core-shell structure with spherically aligned nanorods, was prepared via a simple room-temperature solution-based catalytic route in the case of alpha-MnO2.