Materials Literature
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We study continuous cocycles defined on the set of planar tilings with values in discrete groups. Following Schmidt we show that for generalized domino tilings, L-tiles, and some systems of paths there exists a fundamental cocycle, i.e. we find a cocycle cf, so that all other continuous cocycles c are cohomologous to…
Abstract A study of the thermal‐oxidative degradation of a high barrier ethylene–vinyl alcohol copolymer with 32 mol% of ethylene (EVOH) has been carried out by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier‐transform infrared spectroscopy (FTIR) under mild temperature conditions…
Abstract The application of the miniemulsion process to synthesize polyurethane dispersions with diameters of about 200 nm in a one‐step procedure, free of molecular weight restrictions, is described. With IR and NMR spectroscopy, it is shown that the reaction of the diisocyanate with the diol is the main reaction, wh…
Here we offer results obtained in laboratories and industry, concerning the kinetic study of steelfounding in cement manufacture. We choose the most suitable grinding system, valuing also its economical and environmental repercussion. The obtained results indicated that the kinetic method is extremely useful to solve…
We present molecular dynamics simulations of the influence of point defects on the shear elastic properties of copper. We find that vacancies do not influence these properties at all, while the introduction of interstitials causes a large reduction of the elastic coefficients. The simulations establish a phase diagram…
Hemispherical reflectance and internal quantum efficiency (IQE) measurements have been employed to evaluate the response of Si nanostructured surfaces formed by using reactive ion etching (RIE) random texturing techniques. Random RIE-textured surfaces typically exhibit broadband anti-reflection behavior with solar-wei…
The “intrinsic” fluorescence of carboxylate-terminated polyamido amine (PAMAM-CT) dendrimers is studied by two fluorescence techniques—excitation-emission matrices (EEMs) and lifetimes. The EEMs show similar spectral profiles for all dendrimer generations (a broad peak with an excitation and emission maximum of 380 an…
The relationship between the imide structures and morphology are discussed in order to develop heat resistant polyimides having excellent processability and toughness. Addition-type imide oligomers consisting of asymmetric 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4′-oxydianiline (3,4′-ODA) and/or 4…
Metastable (β and γ) and stable (α) MnS crystallites were synthesized by solvothermal reaction in various solvents at 190−200 °C. In tetrahydrofuran and benzene, the metastable MnS crystallites can be obtained. In water, ammonia liquor, ethylenediamine, α-MnS, which is converted from the metastable phase, would be obt…
A general microscale protocol for the determination of absolute configurations of primary amino groups or secondary hydroxyl groups linked to a single stereogenic center is described. The chiral substrates are linked to the achiral trifunctional bidentate carrier molecule (3-aminopropylamino)acetic acid (1, H(2)NCH(2)…
From 1934 to 1938, Bethlehem Steel Corporation initiated a series of outdoor corrosion tests involving several hundred low-alloy steel compositions. These tests were conducted in the industrial atmospheres of Bethlehem, PA, Pittsburgh, PA, and Columbus, OH, for up to 16 years. The purpose was to define the effects of…
Fuller's earth and acid activated smectitic clays are largely used as bleaching earth for the industrial processing of vegetable, animal and mineral oils and waxes. The paper comments about the nomenclature used for these materials, the nature of the acid activation of smectitic clays (bentonites), activation laborato…
The effect of quantum lattice fluctuations on the optical-absorption spectra in the ground state of halogen-bridged mixed-valence transition-metal linear-chain complexes is studied by using a one-dimensional extended Peierls-Hubbard model. The nonadiabatic effects due to finite phonon frequency $ω_π>0$ are treated thr…
Thin films of MgB2 superconductor were prepared by three different procedures on sapphire and silicon substrates. Boron thin films, ex-situ annealed in magnesium vapour, resulted in textured polycrystalline films with crystal dimensions below about 1000 nm, onset critical temperature Tcon near 39 K and width of phase…
A novel continuous-compositional-spread (CCS) technique based on the nonuniformity of the deposition rate typically observed in pulsed-laser deposition (PLD) is introduced. Using rapid (submonolayer) sequential deposition of the phase spread’s constituents, intermixing of the constituents occurs on the atomic scale du…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTApplications of Synchrotron-Based X-ray MicroprobesPaul M. Bertsch and Douglas B. HunterView Author Information Advanced Analytical Center for Environmental Sciences, Savannah River Ecology Laboratory, The University of Georgia, Drawer E, Aiken, South Carolina 29802 Cite thi…
Nanoparticles of indium oxide, a transparent conducting oxide with a band gap close to GaN, were synthesized by pulsed laser ablation of a pure indium metal target. X-ray diffraction and transmission electron microscopy confirmed that nanocrystalline indium oxide particles with a mean diameter of 6.6 nm with a cubic c…
The oxidation of CO on single Pd atoms anchored to MgO(100) surface oxygen vacancies is studied with temperature-programmed-reaction mass spectrometry and infrared spectroscopy. In one-heating-cycle experiments, CO(2), formed from O(2) and CO preadsorbed at 90 K, is detected at 260 and 500 K. Ab-initio simulations sug…
Topology related changes in the local density of states near the apex of carbon nanocones are investigated using both tight-binding and ab initio calculations. Sharp resonant states are found to dominate the electronic structure in the region close to the Fermi energy. The strength and the position of these states wit…
Pure and La doped Ba0.6Sr0.4TiO3 thin (BST) films were fabricated via the metalorganic solution deposition technique using carboxylate-alkoxide precursors on Pt–Si substrates. The La doping concentration, from 0 to 10 mol %, was found to have a strong influence on the 750 °C postdeposition annealed films material prop…