Materials Literature
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Density functional methods were used to study the environmental dependence of O vacancy formation in CeO2. It was found that an O vacancy in the 2+ charged state has the lowest formation energy for a wide range of Fermi energies (EF) from 0 to ∼1.9eV, while a neutral vacancy becomes the most stable at higher EF values…
A series of cardenolides and related compounds have been isolated from the aerial parts and roots of the ornamental milkweed, Asclepias curassavica. Their structures were determined by spectroscopic and chemical methods. Among them, three derivatives of calactinic acid methyl ester (13-15), 19-nor-16 alpha-acetoxy-10…
Abstract A nanosize CaCO 3 filler was synthesized by an in situ deposition technique, and its size was confirmed by X‐ray diffraction. CaCO 3 was prepared in three different sizes (21, 15, and 9 nm). Styrene–butadiene rubber (SBR) was filled with 2–10 wt % nano‐CaCO 3 with 2% linseed oil as an extender. Nano‐CaCO 3 –S…
Abstract Filtration paper was coated with a thin polyaniline film. The content of conducting polymer was 8.2 and 6.3 wt % for polyaniline hydrochloride and polyaniline base, respectively. After burning, the coated material retains the original fibrilar morphology of cellulose. The polyaniline coating converts to solid…
[reaction: see text] A new [3 + 3] Schiff base macrocycle incorporating naphthalene groups has been prepared. By examination of its properties, X-ray crystallography of model compounds, and calculations, it has been determined that the macrocycle exists predominantly as the keto-enamine tautomer. This unexpected tauto…
Conduction in thin films of PbSe nanocrystals doped by electrochemical gating has been studied. Charging the film, with either electrons or holes, increases the conductance by orders of magnitude. The electrons in the 1S(e) state of nanocrystals in these films have a mobility as high as 5.0 x 10(-3) cm(2) V(-1) s(-1).…
Adsorption of oxygen atoms, achieved via electron-induced dissociation of nitrogen dioxide, induces restructuring of the ``herringbone'' to a striped, soliton-wall structure accompanied by release of gold from the ``elbows'' in the herringbone structure. The number density of ``elbows'' (dislocations corresponding to…
Acid-treated carbon nanotubes are reacted with metal halides and water and are then calcined to produce a chemically bonded oxide layer of controllable thickness on the nanotubes (see figure). Similar coatings are prepared on aluminum oxide and silicon nanowires by the reaction of the metal halides with the surface hy…
Combinatorial materials science requires parallel advances in materials characterization. A high-throughput nanoscale synthesis/nanomechanical profiling approach capable of accurately screening the mechanical properties of 1,700 photopolymerizable materials (see Figure, scale bar: 100 μm) within a large, discrete poly…
Abstract There are many variables in the preparation of aqueous polyurethane (PU) dispersions. Carboxylic acid content, solid content, degree of pre/postneutralization of the carboxylic acids, and chain extension all impact dispersion particle size, viscosity, pH, molecular weights, and glass transition temperature. T…
An extended enzymatic hydrolysis of cotton fibers by crude cellulase from Trichoderma pseudokoningii S-38 is described with characterization of both the enzyme changes of activities and cellulose structure. The hydrolysis rates declined drastically during the early stage and then slowly and steadily throughout the who…
Magnetic nanostructures on non-magnetic or magnetic substrates have attracted strong attention due to the development of new experimental methods with atomic resolution. Motivated by this progress we have extended the full-potential Korringa-Kohn-Rostoker (KKR) Green function method to treat non-collinear magnetic nan…
This article describes a simple heat model of the vacuum arc remelting (VAR) process that includes solution of the nonlinear heat conductivity equation with the nonlinear boundary conditions which are typical for VAR process. The finite-difference analogue of the model equations was obtained through the finite volume…
Zr precipitates in Al to form the phase Al3Zr. For a low supersaturation in Zr of the fcc solid solution, it has been observed that during the precipitation first steps the Al3Zr precipitates have the metastable L12 structure and that they transform themselves to the stable DO23 structure for long enough annealing tim…
Stationary phases that provide high resolutions and are stable at high temperatures are of significant importance in chromatographic analysis. Carbon nanotubes (CNTs) are known to have high thermal and mechanical stability and have the potential to be high-performance separation media that utilize the nanoscale intera…
Magnetic nanocrescent Raman probes (see Figure) can not only serve as stand-alone surface-enhanced Raman scattering (SERS) substrates with high local electromagnetic-field enhancement factors, but can also be controlled by external magnetic fields to produce translational and rotational motion of the nanoprobes. Their…
A polyoxometalate-based hybrid is produced by the copolymerization of a terminal-unsaturated surfactant- encapsulated polyoxometalate and methyl methacrylate. This hybrid exhibits flexible processability, high transparency of the polymer, and high fluorescence of the inorganic cluster (see Figure). The method presente…
Type-II core/shell quantum dots are characterized by a staggered alignment of conduction and valence bands (see Figure), giving rise to a broad tunability of absorption and emission wavelengths. Colloidal ZnTe/CdE (E = S, Se, Te) core/shell quantum dots have been prepared with emission quantum yields of up to 30 %. Th…
Uncertainty about the effects of climate change on terrestrial soil organic C stocks has generated interest in clarifying the processes that underlie soil C dynamics. We investigated the role of soil mineralogy and aggregate stability as key variables controlling soil C dynamics in a California conifer forest. We char…
The continuum theory of domain structures in ferromagnetic/superconducting bilayers fails when the equilibrium domain size becomes comparable with effective penetration depth $Λ$. Instead, a lattice of discrete vortices must be considered. Here, we report our results on the discrete vortex lattices in stripe domain st…