Materials Literature
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Electron momentum spectroscopy (EMS) has been used to measure the valence band electronic structure of thin magnesium and magnesium oxide films. The band structures have also been calculated within the linear muffin-tin orbital (LMTO) approximation. The free-electron-like parabola characteristic of metallic solids was…
The reaction mechanism of poly(benzo[1,2- d:5,4- d ‘]bisoxazole-2,6-diyl-1,4-phenylene) (PBO) at elevated temperatures was studied by means of model compounds and a 13 C-labeled PBO polymer. Products from model compound thermal degradation suggest that the dominating reactions are homolytic scission of a single bond a…
We report on the photoluminescence properties of CuCl thin films with the thicknesses of 20 and 100 nm under intense-excitation conditions produced with a pulsed nitrogen laser. We have clearly observed two photoluminescence bands with a superlinear (almost quadratic) excitation-power dependence. The high-energy band…
The novel sulfidic mesophase [C14H29N(CH3)3]2MnGe4S10 forms via the surfactant-templated assembly of adamantane Ge4S104- clusters and Mn2+ ions in water. The material possesses a continuous, fully bonded framework of MnGe4S10 which is perforated with large parallel tunnels arranged with hexagonal order. The materials…
Experimental solubilities are reported for 2-hydroxybenzoic acid dissolved in 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pentanol, 1-octanol, dibutyl ether, 1,4-dioxane, tetrahydrofuran, ethyl acetate, butyl acetate, 2-propanone, 2-butanone, and cyclohexanone at 298.15 K.…
Human keratinocytes were cultured on plasma copolymers (PCPs), self-assembled monolayers (SAMs), and tissue culture poly(styrene) (TCPS). Plasma copolymerization was used to deposit films with controlled concentrations of carboxylic acid functional groups (<5%). Human keratinocytes were cultured onto these PCP surface…
Four different types of core−shell tecto-(dendrimer) were imaged by tapping-mode atomic force microscopy (AFM). The tecto-(dendrimer) molecules were based on PAMAM dendrimers, and included G4G3, G5G3, G6G4, and G7G5 (the first number represents the generation number (G) of the core, and the second number, the generati…
Ordered aluminosilicate mesostructures having a SiO 2 /Al 2 O 3 ratio near 5 were prepared using a surfactant-templated synthesis. The solid structures were analyzed by scanning electron microscopy (SEM), nitrogen sorption to determine pore volume and pore sizes, powder X-ray diffraction (PXRD), thermal desorption of…
A new methodology is presented for calculating parameters of complex surface reaction mechanisms. This approach takes into consideration adsorbate−adsorbate interactions along with their influence on the activation energies of surface reactions as a function of operating conditions. It combines an extension of the uni…
Nanosize bundles of huge lengths of silica-nanotubes were synthesized by a surfactant-assisted templating mechanism in a laurylamine hydrochloride/tetraethoxysilane system with the aid of trimethylsilylation treatment. The transmission electron microscopy images confirmed the formation of the bundles of silica nanotub…
Electron spin resonance (ESR) spectra of Eu 2+ and Tb 4+ were observed at room temperature in one fluoride phosphate and two phosphate glasses. Although both ions are isoelectronic, they have different ESR spectra. Eu 2+ ions exhibit pronounced features at effective g -values of 2.0, 2.8 and 6.0, which is typical for…
The interaction of ultrathin Cu films with Pd(111) was studied by X-ray photoelectron spectroscopy (XPS). The effects of Cu coverage and annealing temperature were investigated. The XPS data show that at room temperature Cu grows on Pd(111) layer-by-layer without alloying. Furthermore, Cu 2p 3/2 core-level shifts as a…
We present a new technique for preparing and characterizing brushes consisting of weak acidic monomers. The brushes consist of polystyrene−polyacrylic acid block copolymers. The block copolymers are deposited from the air/water interface on a hydrophobically modified Si wafer via the Langmuir−Blodgett technique. The t…
l -Lactide was ring-opening polymerized in the melt by using different organic monocarboxylic iron complexes. The complexes were those of iron and acetic acid, butyric acid, isobutyric acid, dichloroacetic acid, and trifluoroacetic acid. The polymerization temperature was in the range 170−210 °C, polymerization time b…
Alternating nanoparticle/polymer composite multilayers have been assembled on submicrometer-sized polystyrene (PS) latex spheres by the sequential adsorption of silica nanoparticles (SiO 2 ) and poly(diallyldimethylammonium chloride) (PDADMAC) from aqueous solutions. Growth of the composite multilayers on the PS latic…
Solutions of the synthetic clay Laponite are strongly viscoelastic, even at very low particle concentrations. The formation of a gel, evidenced by the existence of a fractal network, has been invoked in explaining the viscoelasticity. We study the structure and viscosity of Laponite using static light scattering and r…
We solve a one-dimensional sandpile problem analytically in a thick flow regime when the pile evolution may be described by a set of linear equations. We demonstrate that, if an income flow is constant, a space periodicity takes place while the sandpile evolves even for a pile of only one type of particles. Hence, gra…
We explore the consequences of the excluded volume interaction of hard spheres at high densities and present a theory for excited granular materials. We first demonstrate that, in the presence of gravity, the granular density crosses over from Boltzmann to Fermi statistics, when temperature is decreased in the weak ex…
The polymorphic modifications \ensuremath{\alpha}, \ensuremath{\beta}, and $\ensuremath{\gamma}{\mathrm{Fe}}_{2}{\mathrm{WO}}_{6}$ of the iron (III) tungstate have been investigated by resistivity and electron paramagnetic resonance (EPR) measurements. The high-electrical resistivity for all phases complies with the d…
Frequency- and temperature-dependent conductivity has been studied by optical spectroscopy for perovskite titanates, which are typical three-dimensional correlated metals. Extended Drude analysis of the data indicates that only one parameter, the ${T}^{2}$ coefficient of the scattering rate, dominates the temperature…