Materials Literature
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The thermal reaction of single-wall carbon nanotubes with in situ generated aryl diazonium compounds is described and is compared to a previously reported, electrochemically induced reaction with preformed aryl diazonium salts.
Optimal co-doping concentrations and dynamics of energy transfer processes for Tm3+-Tb3+ and Tm3+-Eu3+ in LiYF4 crystal hosts, J T Vega-Durán, L A Díaz-Torres, M A Meneses-Nava, J L Maldonado-Rivera, O Barbosa-García
Fluorescence upconversion experiments were performed on monomer solutions of a number of structurally similar thiacarbocyanine dyes. The results from these time-resolved experiments combined with the data obtained from steady-state absorption and emission and 1 H NMR spectra allowed us to assign the components with di…
Spontaneous pattern formation in hybrid nematic liquid-crystal films on glycerol was studied with both polarized transmission and unpolarized monochromatic reflected light microscopy. These observations reveal that the patterns that are found in 1 to 10-microm-thick films are due to a combination of film topography, g…
Polyaniline (PANI) zeolite composites have been prepared by oxidative polymerization of anilinein the presence of zeolite 13X, producing composite materials with PANI/zeolite weight ratios from about 0.5 to 55. The DC conductivity of the composite materials decreased exponentially with zeolite weight fraction. Pure PA…
The influence of the solvent (water, acetone, and ethanol) used during alumina impregnation on the properties of Pt/Al 2 O 3 and Pt−Sn/Al 2 O 3 catalysts was studied. Catalysts were characterized by H 2 chemisorption, TEM, temperature-programmed reduction, ammonia temperature-programmed desorption, UV−vis spectroscopy…
Short-wavelength visual pigments (SWS1) have lambda(max) values that range from the ultraviolet to the blue. Like all visual pigments, this class has an 11-cis-retinal chromophore attached through a Schiff base linkage to a lysine residue of opsin apoprotein. We have characterized a series of site-specific mutants at…
Atomistically detailed models of free-standing thin films and the bulk structure of amorphous atactic polystyrene have been produced by reverse mapping from equilibrated coarse-grained models. The bridging technique employed in the simulation allows the generation of a moderate sized atomistic system (six independent…
The electronic band structure of the Peierls compound NbSe3 has been explored for its symmetries with microspot synchrotron photoemission. The Fermi level crossings and deviations from one-dimensional behavior are identified. Density-functional calculations of the Fermi surfaces confirm the nesting conditions relevant…
Arrays of polypyrrole (Ppy) dots (80−180 nm diameter) have been prepared in a highly parallel fashion. This process is achieved by templating Ppy growth on a 2D surface micelle array, initially formed by the Langmuir−Blodgett (LB) technique. Ppy growth on self-assembled (SA)-based surface micelles produces more comple…
There exists a need to synthesize PMOs with bridging organic groups beyond the few that are accessible from commercially available bis(triethoxysilyl)organic precursors. To fulfill this need, three new periodic mesoporous arylsilicas, aromatic PMOs, having bridging aromatic organic groups as an integral part of the fr…
We report ab initio quantum mechanical calculations on LnIII(NO3−)n (n = 1–3) and Ln(NO3)3(H2O)m (m = 4–6) complexes to compare the monodentate s. bidentate binding mode of nitrate anions to trivalent lanthanide cations (LaIII, EuIII and LuIII) in the gas phase. In all LnIII(NO3−)n complexes studied, bidentate coordin…
A two-dimensional model has been developed to simulate heat transfer and solidification phenomena of squeeze cast magnesium alloy (AZ91D). The model was based on the control-volume finite-difference approach and on the enthalpy method. The computation was carried out to understand the effect of varying processing para…
Abstract The thermal oxidation of poly(bismaleimide) of the F655‐2 type, supplied by Hexcel‐Genin, was studied by isothermal gravimetry at 180, 210, and 240°C and various oxygen pressures ranging from 0 to 1.2 bar. Comparison of various sample thicknesses and visible microscopy observations on bulk aged samples shows…
The dispersion behaviors of copper oxide on the mechanical mixture of CeO 2 and γ-Al 2 O 3 supports, CuO/CeO 2 + γ-Al 2 O 3, have been characterized by using XRD, LRS, XPS, UV-DRS, and TPR. The results show that copper oxide dispersed mainly on the surface of CeO 2 support, provided that the loading amount of copper o…
Several 1,2-benzenedicarboxylic acid, 4-sulfo, 1,2-di(alkyl), or di(alkoxy) esters were synthesized and tested as plasticizing dopants which lead to solution processible (via counterion) polyaniline with improved mechanical properties and metallic-type conductivity. As evidenced by wide-angle X-ray diffraction and sma…
A first-order liquid-liquid (LL) phase transition as a function of temperature in Pb-Sn melts is suggested by internal friction experiments and verified by differential thermal analysis with an entropy-driven order-disorder mechanism. It differs remarkably with other already found LL phase transitions in some aspects.…
A series of poly(ethylene oxide) (PEO)/poly(epsilon-caprolactone) (PCL) containing biodegradable poly(ether ester urethane)s, covering a wide range of compositions, were synthesized and characterized. The synthesis consisted of a two-step process. During the first step, the ring-opening reaction of epsilon-caprolacton…
The fluorescence from thin films of poly[1-phenyl-2-(4-trimethylsilylphenyl)ethyne] (PTMSDPA) is strongly quenched by the vapors of a variety of nitroaromatic compounds present at levels ranging from parts-per-million to parts-per-billion in air. The quenching is believed to arise because of the formation of charge-tr…
Antiferromagnetism in stacked nanographite is investigated with using the Hubbard-type models. The A-B stacking or the stacking near to that of A-B type is favorable for the hexagonal nanographite with zigzag edges, in order that magnetism appears. Next, we find that the open shell electronic structure can be an origi…