Materials Literature
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“Aerosol catalysis” is shown to be a powerful tool for investigating the catalytic properties of freshly formed nanoparticles in situ and without substrate interference. The method is first outlined conceptually, followed by an illustrative application to the catalytic formation of methane on a nickel nanoaerosol. Rea…
Polarized absorption and emission spectra of trigonal single crystals of an Er(III) complex coordinated to a heptadentate tripodal ligand are reported at temperatures between 8 and 298 K. The assigned energy levels below the onset of ligand absorption (< 25 000 cm(-1)) are fitted to a parametrized electronic Hamiltoni…
Multicomponent arrays based on a central iridium(III) bis-terpyridine complex (Ir) used as assembling metal and free-base, zinc(II) or gold(III) tetraaryl-porphyrins (PH(2), PZn, PAu) have been designed to generate intramolecular photoinduced charge separation. The rigid dyads PH(2)-Ir, PZn-Ir, PAu-Ir, and the rigid a…
Fluorescence “blinking” kinetics of isolated colloidal InP quantum dots (QDs) are investigated via confocal single molecule microscopy. Analysis of fluorescence trajectories reveals inverse power law behavior (∝ 1/τ m ) in on/off time probability densities with m on ≈ 2.0(2) and m off ≈ 1.5(1). Such an inverse power l…
Valence-band dispersions in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ along the $\ensuremath{\Gamma}\ensuremath{-}\ensuremath{\Delta}\ensuremath{-}X$ line $(k\ensuremath{\Vert}[001])$ are obtained by angle-resolved photoemission spectroscopy. Compared with the spectra of GaAs, a small energy shift…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSol−Gel Derived Nitric-Oxide Releasing Materials that Reduce Bacterial AdhesionBrian J. Nablo, Ta-Yung Chen, and Mark H. SchoenfischView Author Information Department of Chemistry University of North Carolina Chapel Hill, North Carolina 27599-3290 Cite this: J. Am. Che…
A phenomenological coupled exciton model is proposed in order to characterize optical excitations in extended dendrimers. An onsite exciton state is assigned at each phenyl rings and a nearest neighbor hopping integral which obeys the Gaussian distribution is considered between the exciton states. The decreasing optic…
Antiferromagnetism in stacked nanographite is investigated with using the Hubbard-type model. The A-B stacking is favorable for the hexagonal nanographite with zigzag edges, in order that magnetism appears. Next, we find that the open shell electronic structures can be origins of the decreasing magnetic moment with th…
The paper presents discussion on up to date results on MgB2 conductors from the point of view of their future dc and ac applications. Basic physical parameters of MgB2 compound relevant to conductors are introduced. Different conductor preparation methods and conductor architectures are presented and attainable critic…
We report on a numerical study of quantum diffusion over $\ensuremath{\mu}\mathrm{m}$ lengths in defect-free multiwalled nanotubes. The intershell coupling allows the wave packet spreading over several shells, and when their periodicities along the nanotube axis are incommensurate, electronic propagation is shown to f…
We examine and identify magnetoresistance mechanisms in 2D system containing a sizable concentration of magnetic ions. We argue that some of these mechanisms can serve as a tool to measure spin polarization. Lack of spin degeneracy and enhanced localization make it possible to detect an additional QHE plateau associat…
Abstract The synthesis of boron‐modified polysilazanesof general type {B[C 2 H 4 Si(R)NR′] 3 } n [R = CH 3 , (NR′) 0.5 ; R′ = H, CH 3 ] by dehydrogenative coupling of tris(hydridosilylethyl)boranes B[C 2 H 4 Si(CH 3 ) n H 3− n ] 3 (C 2 H 4 = CHCH 3 , CH 2 CH 2 ; n = 0, 1) and ammonia or methylamine is reported. Deta…
Abstract The dynamic mechanical properties of hybrids of chlorinated polyethylene (CPE) and 3,9‐bis[1,1‐dimethyl‐2{β‐(3‐ tert ‐butyl‐4‐hydroxy‐5‐methylphenyl)propionyloxy}ethyl]‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) were investigated. The CPE/AO‐80 hybrids showed a novel relaxation in addition to the glass tran…
Abstract We have investigated the formation of high‐strength, high‐modulus fibers from four aliphatic polyketone resins. One resin was a perfectly alternating copolymer of ethylene and carbon monoxide, while the other three were terpolymers containing up to 6 mol % propylene. The mechanical properties were measured as…
Abstract Phase equilibria and phase reactions of precursor‐derived ceramics of the Si–C–N and the Si–B–C–N systems at temperatures higher than 1700 K are described. CALPHAD (CALculation of PHAse Diagrams) results confirm quantitatively the data from thermogravimetry and differential thermal analysis of precursor‐deriv…
Abstract Regenerated cellulose fibers from rice straws with a diameter of 10 to 25 μm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/ N ‐methylmorpholine‐ N ‐oxide (MMNO) solution. X‐ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (…
l -Lactide macromonomers with an incorporated double bond were successfully synthesized by controlled ring-opening polymerization initiated by two new cyclic tin alkoxides (1,1-di- n -butyl-stanna-2,7-dioxacyclo-4-heptene and 9,9,20,20-tetrabutyl-8,10,19,21-tetraoxa-9,20-distanna-dispiro[5.5.5.5]docosa-2,14-diene). In…
With the goal of developing diverse building blocks for nanocomposite materials, we have now learned to synthesize liquid crystalline materials by appending mesogenic groups to cubic silsesquioxane cores (LC cubes) via hydrosilylation of allyloxy functionalized mesogens ( 4, 5, 8, and 9 ) with octakis(dimethylsiloxy)o…
[reaction: see text] Dendrimers containing an encapsulated tertiary amine were prepared by coupling tris(2-aminoethyl)amine with dendritic branches derived from L-lysine. These dendrimers were used as catalysts in the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde and nitroethane, and their catalytic performa…
Abstract Processing of two precursor‐derived SiCN ceramic monoliths was performed employing different liquid polymers, which were obtained by ammonolysis of functionalized chlorosilanes. Preparation of monolithic samples was performed by mixing liquid polysilazane with cross‐linked SiCN‐powder particles, derived from…