Materials Literature
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We report a clear correspondence between changes in the Curie temperature and carrier density upon annealing in epitaxially grown (Ga,Mn)As layers with thicknesses in the range between 5 and 20 nm. The changes are dependent on the layer thickness, indicating that the (Ga,Mn)As–GaAs interface has importance for the phy…
We report Curie temperatures up to 150 K in annealed Ga1−xMnxAs epilayers grown with a relatively low As:Ga beam equivalent pressure ratio. A variety of measurements (magnetization, Hall effect, magnetic circular dichroism and Raman scattering) suggest that the higher Curie temperature results from an enhanced free ho…
We experimentally determine ensemble-averaged responses of granular packings to point forces, and we compare these results to recent models for force propagation in a granular material. We used 2D granular arrays consisting of photoelastic particles: either disks or pentagons, thus spanning the range from ordered to d…
We report room-temperature time-integrated and time-resolved photoluminescence (PL) measurements on a nominally undoped wurtzite ZnO thin film grown on (001) silicon. A linear and sublinear excitation intensity Iex dependence of the PL intensity were observed for the 379.48-nm exciton line and the weak broad green ban…
The appropriate heat treatment of the Gd5Si2Ge2 alloy prepared from high-purity Gd results in a considerable enhancement of its magnetocaloric effect. The maximum magnetic entropy change increases by ∼80% (from ∼20 to 36 J/kg K) and the adiabatic temperature change increases by ∼55% (from ∼11 to 17 K) for a magnetic f…
The direct synthesis of hydrogen peroxide from H2 and O2 using a range of supported metal catalysts is described and discussed. A detailed study of the factors influencing the formation and decomposition of hydrogen peroxide is presented for a Pd/sulfonated carbon catalyst in a methanol/water solvent. The use of low t…
We measure two-dimensional profiles of collimated microwave beams transmitted through composite wire and split-ring resonator prisms. Prior experiments suggest these structures have a negative index of refraction, though these claims have been questioned. Our 2D measurements demonstrate that transmission obeys Snell's…
The manganese oxides of general formula RE 1− x M x MnO 3 (RE = rare earth, M = Ca, Sr, Ba, Pb) have remarkable interrelated structural, magnetic and transport properties induced by the mixed valence (3 + –4 + ) of the Mn ions. In particular, they exhibit very large negative magnetoresistance, called colossal magnetor…
Abstract In this article, the kinetics of thermal decomposition of unsaturated maleic–phthalic polyester resins, flame‐retarded with zinc hydroxystannate, was studied by thermogravimetric analysis at different heating rates. At the first stage, it was found, on the basis of isoconversional analysis by the methods of F…
Under Friedel-Crafts conditions, meso-tetraarylporphyrins give porphyrin spiro dimers in good yield. This reaction involves acylation, acid-catalyzed cyclization, and dimerization. A stable dimer possessing three additional six-membered rings could be isolated and its structure determined. By modifying the substrate a…
Abstract The kinetics of aqueous phase catalytic hydrogenation of maleic acid to succinic acid were studied in a slurry reactor between 323 and 353 K using a hydrogen partial pressure range of 1.03–2.06 MPa, with a 5% Ru/Al 2 O 3 catalyst. The initial rate data were analyzed using a power law model. Above 1.72 MPa hyd…
Covalently linked Au-NPs micropatterns have been successfully fabricated from the self-assembly film composed of 4-mercaptophenol-capped Au nanoparticles (Au-NPs) and -N2+ containing polymers of nitro-diazoresin (NDR) by selective exposure to UV light and development in sodium dodecyl sulfate (SDS) aqueous solution. T…
Abstract Conductive homopolymers and composites of poly(2‐chloroaniline) (P2ClAn) and polyfuran (PFu) were synthesized chemically in hydrous and anhydrous media, and their properties were investigated. The polymers and composites were characterized by Fourier infrared spectroscopy, ultraviolet‐visible absorption spect…
We have investigated the interplay between disorder and ferromagnetism in ${\mathrm{III}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{V}$ semiconductors. Our study is based on a model in which $S=5/2$ Mn local moments are exchange coupled to valence-band holes that interact via Coulomb interactions with each other, wit…
Anodic oxidation of tetraspirobifluorene-manganese porphyrin lead to the coating of the working electrode by insoluble electroactive poly(9,9'-spirobifluorene-manganese porphyrin) films for which electrochemical behaviour and physicochemical properties are described; these polymeric materials are able to catalyze the…
Beta-unsubstituted meso partially free N-confused porphyrin, N-confused 5,20-diphenylporphyrin (NCDPP, 3), was synthesized in 7% yield by [3 + 1] condensation reaction followed by oxidation. The structures of the free base and its Ag(III) complex were elucidated by the single-crystal X-ray analyses. The Ag(III) comple…
Abstract A high mordenite product was obtained from a natural raw material, diatomite, either with or without the presence of diethanolamine. The synthesis process took 2 days, and was carried out under hydrothermal conditions, at autogenic pressure, and at a temperature of 180 °C. The resulting crystals were identifi…
Abstract All‐polypropylene (PP/PP) composites, consisting of homoisotactic PP fibers and a propylene–ethylene random copolymer matrix, were manufactured. The interfacial morphologies and mechanical deformation of the composites were investigated. It was found that a transcrystalline layer was formed in the matrix depe…
The destabilization of confined ultrathin poly(styrene- block -paramethylstyrene) films with a fully deuterated polystyrene block in the strong segregation limit is investigated. Using the spin-coating technique, polymer films with thicknesses smaller than the radius of gyration of the unperturbed polymer molecule wer…
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