Materials Literature
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We have grown epitaxial La2/3Sr1/3MnO3 (LSMO) and La2/3Ba1/3MnO3 (LBMO) thin films as well as La2/3Ba1/3MnO3/SrTiO3 heterostructures by pulsed-laser deposition. The microstructure of the films was analyzed by x-ray diffraction and transmission electron microscopy. A significant effect of strain due to lattice mismatch…
Thermally induced threefold infrared-to-visible upconversion emission enhancement in Er3+/Yb3+-codoped Ga2S3:La2O3 chalcogenide glasses excited at 1.064 μm is reported. The times three upconversion efficiency enhancement was achieved by heating the sample in the temperature range of 23–155 °C, and is assigned to the t…
Epitaxial thin films of ordered double-perovskite Sr2FeMoO6−y are deposited on (001) SrTiO3 substrates by pulsed-laser deposition using a two step growth process. Selection of growth conditions is found to lead to either highly conductive metallic thin films (residual resistivity of about 1 μΩ cm) or semiconducting fi…
Nanodiamond powder was annealed at each of the following temperatures: 300, 600, 800, 1000, and 1150 °C, for an hour in flowing argon ambient. The variations of x-ray diffraction patterns and Raman spectra of the powder with different annealing temperatures were studied. While being annealed at temperatures higher tha…
The effect of an external electric field F on the excitonic photoluminescence (PL) spectra of a symmetric coupled double quantum well (DQW) is investigated both theoretically and experimentally. We show that the variational method in a two-particle electron-hole wave function approximation gives a good agreement with…
Eine schnelle Bestimmung von Bindungsaktivität direkt aus Mischungen potentieller Liganden ist mit der hier beschriebenen NMR-Methode möglich, bei der der Sättigungstransfer auf kurzzeitig an ein Protein gebundene Moleküle genutzt wird. Zusätzlich läßt sich das Bindungsepitop sehr einfach ermitteln. Hohe Empfindlichke…
A five-coordinate chloride ion is believed to template the assembly of a pentadecanuclear lanthanide complex of europium(III). This cluster (see picture) has been prepared by coordination of europium(III) perchlorate with tyrosine at about pH 6. Single crystal X-ray analysis established an unprecedented structure in w…
There are few investigations of the influence of filler dispersion on the thermal diffusivity of carbon black rubber compounds. In this article, experimental results of a cured styrene–butadiene rubber (SBR) compound are presented in the range of temperatures between 210 and 350 K at four levels of dispersion obtained…
Polyacrylonitrile (PAN) polymers were prepared by inclusion polymerization of the monomer using various molar equivalents of β-cyclodextrin (β-CD). Stereoregular (isotactic, atactic and syndiotactic) distributions of the prepared PAN polymers were determined from terminal model Bernoullian statistics using 13C-NMR dat…
From a survey of the literature on grafting free radical polymerization from solid surfaces we suggest kinetic schemes for the process. The system of differential equations in partial derivatives including the diffusion equation based on the classical theory of free radical polymerization and the assumption that surfa…
We report on the synthesis, kinetics of proteolysis by trypsin, and morphological characterization of a novel lipidated decapeptide that spontaneously self-assembles in aqueous solutions into 0.5 μm diameter hollow tubules and helices that range in length from tens to hundreds of micrometers depending on formation con…
Ultrathin layers of a new metallosupramolecular iron(II) coordination−polyelectrolyte containing 1,4-bis(2,2‘:6‘,2‘ ‘-terpyridine-4‘-yl)benzene ( 1 ) have been prepared by alternating adsorption from dilute solution. Adsorption on oppositely charged surfaces and layer-by-layer growth were investigated in situ by surfa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSuprasupermolecules with Novel Properties: MetallodendrimersGeorge R. Newkome, Enfei He, and Charles N. MoorefieldView Author Information Center for Molecular Design and Recognition, Department of Chemistry, 4202 East Fowler Avenue, University of South Florida, Tampa, Florid…
PCR random mutagenesis in the cysE gene encoding Escherichia coli serine acetyltransferase was employed to isolate the mutant enzymes that, due to a much less feedback inhibition by L-cysteine, cause overproduction of L-cysteine and L-cystine in the recombinant strains. The L-cysteine auxotrophic and non-utilizing E.…
The complexation of poly[(acrylamidopropyl)trimethylammonium chloride] with sodium [bis(perfluorohexylethyl)-2-sulfosuccinate] (Fluowet SB) in aqueous solution results in a highly ordered mesomorphous polyelectrolyte−surfactant complex. Films prepared from the complex exhibited a remarkably low critical surface tensio…
The colligative properties of poly(propylene imine) dendrimers in methanol have been investigated with low-angle laser light scattering and vapor pressure osmometry. The molecular weights and second virial coefficients of the first five generations have been determined. The molecular weights have been found to agree w…
Density functional theory and ab initio molecular orbital theory have been used to calculate the energetics of C 2 insertion into C 9 H 12 and C 9 H 14 clusters that model unhydrided and monohydrided (100) diamond surfaces, respectively. The reaction of C 2 with either the C 9 H 12 or C 9 H 14 cluster is exothermic by…
Understanding the processes in Earth9s lower mantle requires detailed knowledge of the composition, phase, and physical properties of the mantle minerals, chiefly magnesium silicates with a perovskite structure. Navrotsky (page 1788) argues that lessons can be learned from ceramic perovskites that have been studied in…
In this work we survey selected theoretical developments for models of deposition of extended particles, with and without surface diffusion, on linear and planar substrates, of interest in colloid, polymer, and certain biological systems.
Grand canonical simulations are used to calculate adsorption isotherms of various classical gases on alkali metal and Mg surfaces. Ab initio adsorption potentials and Lennard-Jones gas-gas interactions are used. Depending on the system, the resulting behavior can be nonwetting for all temperatures studied, complete we…