Materials Literature
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The measurement of contact angle on polystyrene (PS) films solvent cast on acid-cleaned glass substrates was used in conjunction with the Lifshitz−van der Waals/acid−base approach in order to investigate the surface functional-group compositions as well as the physical nature and the strength of intermolecular interac…
We have studied the NH 2 + NO reaction theoretically in order to try to deduce a theoretical “model” that will accurately reproduce both the total rate coefficient k T ( T ) and the branching fraction α( T ) of the reaction NH 2 + NO → N 2 + H 2 O (a), NH 2 + NO → NNH + OH (b), and NH 2 + NO → N 2 O + H 2 (c), where k…
Three-dimensional coordination network solids of MII[C(CN)3]2 (M = V, Cr) composition possess interpenetrating rutile-like network structures. Each [C(CN)3]- bonds to three different metal ions in a triangular array, affording a geometrical topology akin to a Kagomé lattice leading to competing spin exchange interacti…
Both convergent and divergent strategies are used to synthesize 1, a dendrimer comprising triazines linked by diamines. The convergent approach is orthogonal; neither protecting groups nor functional group manipulations are required using the building blocks selected.
Stable aqueous dispersions consisting of CdS nanoparticles having modal diameters, ranging between 2 and 8 nm, were prepared with amino-derivatized polysaccharides (aminodextrans, hence abbreviated as Amdex) as the stabilizing agents. The size, stability, and luminescence intensity of such dispersions were shown to be…
The crystal structure of selenomethionine-substituted malate synthase G, an 81 kDa monomeric enzyme from Escherichia coli has been determined by MAD phasing, model building, and crystallographic refinement to a resolution of 2.0 A. The crystallographic R factor is 0.177 for 49 242 reflections observed at the incident…
We present ab-initio local density FLAPW calculations on non-reactive N-terminated [001] ordered GaN/Ag and GaN/Au interfaces and compare the results (such as metal induced gap states and Schottky barrier heights) with those obtained for GaN/Al, in order to understand the dependence of the relevant electronic properti…
The fundamental principles of density functional theory are applied to achieve a better understanding of various theoretical tools for describing chemical reactivity. Emphasis is given to the Fukui function, the central site reactivity index of density functional theory, which is approached through its own variational…
We study the equilibrium and kinetic properties of a model for polydisperse mixture adsorption. The system consists of a bulk phase of hard disks with a given size distribution and overall concentration that adsorb and desorb on a continuous planar surface. The disks adsorb at a rate proportional to their bulk concent…
The graft copolymerization of butyl acrylate onto poly(vinyl alcohol) with ceric ammonium nitrate as redox initiator in a aqueous medium has been investigated. The formation of graft copolymer was confirmed by means of IR, scanning electron microscopy (SEM), and wide-angle X-ray diffraction (WAXD). The percentage of m…
The recycled polyolefinic product from discarded standard car bumpers collected from Rio de Janeiro suburb shops was characterized by mechanical and wide-angle X-ray scattering (WAXS) methods. We found that the recycled plastic mixture is composed mainly of polypropylene (PP), containing ethylene-propylene-diene (EPDM…
Accelerated flex fatigue testing was carried out on nylon 6.6 tire cords, under various applied tensions (stress), at standard atmospheric conditions of 65% relative humidity and 21°C. Fatigue lifetime was measured and scanning electron microscope used to investigate the nature of failure. The study concluded that the…
Ab initio calculations on a linear –OTiOTiO– chain embedded in an envelope of (SiO4) tetrahedra, mimicking the structure of Na2TiSi5O13 molecular sieve (ETS-10), confirm that the peculiar optical properties of the solid are associated with the presence of –OTiOTiO– linear chains behaving as quantum wires. The optical…
Aminoalkyl phenol derivatives were prepared and tested for electrooxidation in alkaline hydroalcoholic electrolytes. We estimated the relative insulating character of thin (<0.3 μm) organic coatings on several metal electrodes (Fe, Cu, and Ni), through both voltammetric and potentiostatic runs. Unsaturated allyl and b…
Low-temperature synthesis of spinels Mg x Co 1 - x Co 2 O 4 ( x = 0.0−0.9) has been investigated with two important synthetic parameters and XRD/FTIR/DSC/BET/ICP/CHN methods. It is found that with an increase in hydrothermal treatment temperature, precursor compounds change from the hydrotalcite-like to brucite-like a…
The two-band Hubbard model with the density of states obtained from the band calculation is applied for FeSi, which is suggested to be a Kondo insulator or a correlated band insulator. Using this model, the correlation effects on FeSi are investigated in terms of the self-consistent second-order perturbation theory co…
Compositionally step-varied (Pb, Ca)TiO3 thin films were prepared on platinum-coated silicon substrates by a monoethanolamine-modified sol-gel technique. The dielectric constant and dissipation factor were found to be 342 and 0.019, respectively, for thin films of 0.6μm in thickness annealed at 550 °C for 60 min. The…
The oxygen-deficiency-activated charge ordering (CO) transition has been observed in C-oriented La2/3Sr1/3MnO3−δ thin films prepared by pulsed laser deposition on LaAlO3 substrates. A rapid growth of the sample resistivity at temperatures below TC is observed, while significant thermal hysteresis and electrical field…
Intra-valence band photocurrent investigations of self-assembled Ge dots in Si are reported. Boron-doped Ge dots of about 70 nm diameter and 6.5 nm height are deposited by molecular beam epitaxy in the Stranski–Krastanov growth mode within the intrinsic region of a p+-i-p+ Si structure. For a broad excitation waveleng…
An icosahedral (I) quasicrystalline phase with a grain size below 40 nm was formed as a metastable phase in crystallization of the bulk glassy Zr65Al7.5Cu17.5−xNi10Mx (M=Ag, Pd, Au, or Pt; x=5 and 10 at %) alloys. The volume fraction (Vf) of the I phase is about 85% for the 5% M alloy and nearly 100% for the 10% M all…