Materials Literature
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Photoacoustic absorption measurements at room temperature are reported for Se1−xTex alloys in both crystalline and amorphous states for 0<x⩽0.3. The optical energy gap thus measured shows two features: (a) the gap decreases linearly as x increases with a change of slope at x=0.1 for both crystalline and amorpho…
Recent research into black powder problems experienced by natural-gas transmission pipelines indicates steps that can be taken to control the material in gas pipelines, gathering systems, and storage facilities. Black powder (the common term for various forms of iron sulfide mixed with contaminants) is the least under…
This work investigates the charge-transfer spectra of and complexes formed in anisotropic (X = Cl, Br) crystals. Attention is paid to the variations of the charge-transfer transition energies induced by chemical pressure effects when substituting along the crystal series. A salient feature of this study is the weak se…
The local atomic and magnetic structure of a powder crystalline sample of MnO has been modelled for a wide range of temperatures (10-1100 K) by fitting neutron powder diffraction data using the reverse Monte Carlo technique (RMC). This method allows simultaneous and self-consistent fitting of Bragg and diffuse scatter…
Carbon nanotubes can flatten into collapsed tubes with bulbs along either edge. The strong anisotropy in the graphitic radiation damage threshold both explains the rapid destruction of face-on flattened nanotubes and can be exploited to selectively modify the structure of edge-on flattened nanotubes, thereby creating…
Low molecular symmetry with regard to the conjugation path of the delocalized electrons was found to be a good guideline towards linearly conjugated molecules with large second-order hyperpolarizabilities γ. We show that this guideline is also valid for two-dimensionally conjugated systems. We experimentally demonstra…
Diamondlike carbon (DLC) was deposited on silicon using a plasma immersion ion deposition (PIID) method. Inductive radio-frequency plasma sources were used to generate Ar and C2H2 plasmas at low gas pressures ranging from 0.04 to 0.93 Pa. The film stress and hardness were sharply dependent upon bias voltage at an oper…
A long lasting green phosphorescence was found in -doped calcium aluminate glasses prepared under a strongly reducing atmosphere. An electron-trapped centre giving an EPR signal at g = 1.999, an analogue of the centre in CaO, was induced by illumination with ultraviolet (uv) radiation and decayed slowly after the illu…
Measurements of the spin-lattice relaxation rate are reported for muons and protons as a function of temperature for different values of the applied magnetic field in the ${\mathrm{Mn}}_{12}{\mathrm{O}}_{12}$ molecular cluster. Strongly field dependent maxima in the relaxation rate versus temperature are observed belo…
Electronic applications of diamond-like carbon have been limited by its relatively high disorder and defect density. We find that the density of paramagnetic defects in hydrogenated tetrahedral amorphous carbon and the Urbach slope of the optical absorption edge can be reduced by annealing at 300 °C, with little effec…
A combination of atomic-resolution $Z$-contrast imaging and first-principles density-functional calculations are used to establish that Ca impurities segregating to particular atomic columns in MgO grain boundaries induce a structural transformation. The presence of Ca in the boundary structure is independently confir…
La 0.6 Sr 0.4 MnO 3 thin films were fabricated on SrTiO3 (001) substrates using pulsed laser deposition with observing persistent intensity oscillation of reflection high-energy electron diffraction. By atomic force microscopy, the surface of resulting films was confirmed to be extremely flat, showing atomically smoot…
We present a new type of basis set which is local, compact, and orthogonal. The basis functions, called orthlets, are centered at the sites of a lattice and are specifically adapted to represent the system being studied. The adaptability includes the ability to have singular behavior within an orthlet, allowing a sing…
A complete interpretation is proposed for the pre-edge fine structure (PEFS) of the x-ray Ti K-absorption spectra for perovskite structure crystals. The interpretation is based on the results of numerous calculations performed by a modified full multiple scattering method which provides the theoretical spectra for the…
We fabricated field-effect transistors based on individual single- and multi-wall carbon nanotubes and analyzed their performance. Transport through the nanotubes is dominated by holes and, at room temperature, it appears to be diffusive rather than ballistic. By varying the gate voltage, we successfully modulated the…
High-temperature molding of a mixture of epoxidized natural rubber (ENR) and intermediate super abrasion furnace (ISAF) carbon black results in strong rubber–filler interaction, the extent of which is greater in the case of the oxidized grade of the carbon black. It has been observed that ENR is bonded to the filler s…
Polymeric chains consisting of alternating Tl2Me4(thf)2 and O2C6H(Me)(t-Bu)−(t-Bu)(Me)HC6O2 (SQ−SQ) subunits have been formed by treating the parent bis(benzoquinone) with Tl(Me)2(3,6-DBSQ). Steric interactions between methyl substituents of adjacent rings result in a dihedral angle of 51.5° between ring planes and st…
Tensile properties, water vapor permeabilities, and water solubilities were determined for casein films plasticized with glycerol. The casein was precipitated from milk that was sparged with carbon dioxide (CO 2 ). The films were compared to those made from commercial calcium caseinate. Glycerol was added to plasticiz…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTFunctional Group Accessibility in Hydrogen-Bonded Polymer Blends. 3. Steric Shielding EffectsGeorge J. Pehlert, Paul C. Painter, and Michael M. ColemanView Author Information Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pe…
Oxidative polymerization of m-phenylenediamine was carried out using H2O2 as an oxidant and horseradish peroxidase as a catalyst in mixtures of aqueous buffer solution and 1,4-dioxane or in reversed micellar solutions. When the reaction mixture was brought into contact with a stainless steel stick, the obtained polyme…