Materials Literature
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The evolution of sheet resistance of n-type single-crystal wurtzite ZnO epilayers exposed to bombardment with MeV H1, Li7, O16, and Si28 ions at room temperature is studied in situ. We demonstrate that sheet resistance of ZnO can be increased by about 7 orders of magnitude as a result of ion irradiation. Due to extrem…
The field emission properties of “porous diamond-like” carbon structures have been characterized. A hot filament chemical vapor deposition system fed with ethyl alcohol vapor diluted in helium was used to deposit the samples. Morphological analysis by field emission scanning electron microscopy revealed that they had…
Sulfur incorporated nanocrystalline carbon (n-C:S) thin films were grown on molybdenum substrates by a hot-filament chemical vapor deposition technique using gas mixtures of methane, hydrogen, and a range of hydrogen sulfide (H2S) concentrations (100–500 ppm with an interval of 100 ppm) at a fixed substrate temperatur…
We studied polarization switching of 295 nm thick 〈111〉-oriented-Pb(Zr0.45Ti0.55)O3 (PZT) thin-film capacitors through a polarization hysteresis loop and piezoelectric force microscopy (PFM) on top of the Pt electrode. Positive voltage pulses of 450 kV/cm and 2.5 ms were applied to the top as a poling pulse. Negative…
We report the discovery of a large magnetic entropy change in La1.4Ca1.6Mn2O7, a bilayered perovskite manganese oxide that has a Curie temperature (TC) of about 270 K and which allows magnetic refrigeration at room temperature. The magnetic entropy changes reach values of 11.3 J K−1 kg−1 and 16.8 J K−1 kg−1 for field…
The covalent attachment of the heme cofactor in c-type cytochromes is a surprisingly complex process, which in bacteria involves a number of different proteins. Among the latter, the ccmE gene product is known to perform a key role in the heme delivery pathway in Gram-negative bacteria. The solution structure of the s…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTThe First Example of Cationic Iron-Coordinated Polyaromatic Ethers and Thioethers with Azo Dye-Functionalized Side ChainsAlaa S. Abd-El-Aziz, Tarek H. Afifi, Wes R. Budakowski, Ken J. Friesen, and Erin K. ToddView Author Information…
Methylobacterium extorquens AM1, a serine cycle facultative methylotroph, accumulates poly-beta-hydroxybutyrate (PHB) as a carbon and energy reserve material during growth on both multicarbon- and single-carbon substrates. Recently, the identification and mutation of the genes involved in the biosynthesis and degradat…
The temporal evolution of the photoexcited state in quasi-one-dimensional (1D) halogen-bridged platinum complexes $[\mathrm{Pt}(\mathrm{en}{)}_{2}][\mathrm{Pt}(\mathrm{en}{)}_{2}{X}_{2}]({\mathrm{ClO}}_{4}{)}_{4}$ (abbreviated as $\mathrm{Pt}\ensuremath{-}X,$ $X=\mathrm{C}\mathrm{l},$ Br or I), has been comprehensivel…
Weakly charged micelles of poly(2-(dimethylamino)ethyl methacrylate) [10% quaternized]- block -poly(2-(diethylamino)ethyl methacrylate) (10qDMA-DEA) adsorb to form a highly ordered monolayer at the mica−solution interface at pH 8.9. Rinsing with solvent at pH 9 has little effect on the adsorbed layer. Reduction of the…
Nanowires of metal borates Al18B9O33 and MgB4O7 were synthesized by thermal evaporation of mixed powders containing metal oxide (Al2O3 or MgO) and boron oxide. Typical widths of these nanowires are in the range of 10 to ∼100 nm and lengths are in the range of several to several tens of micrometers. The nanowires were…
SO 2 and SO2+H2O plasma treatments have been performed on highly oriented pyrolytic graphite, glassy carbon and several polymers in order to functionalize their surface with sulfur in different oxidation states. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy measurements prove that…
A new type of organic intercalation system using poly(muconic acid) and poly(sorbic acid) crystals as the host compounds is described. The layered polymer crystals as the host are derived from benzyl-, dodecyl-, or naphthylmethylammonium salts of (Z,Z)-muconic or (E,E)-sorbic acids by topochemical polymerization. The…
Structural and physical properties of ferroelectric and ferrimagnetic pulsed-laser deposition-grown thin-film BaFexTi1−xO3 with 0.5⩽x⩽0.75 (BFTO) are compared with those of BaTiO3 (BTO) films deposited under identical conditions. Fe leads to lattice expansion and deterioration of the crystalline quality in the as-prep…
Two dielectric relaxation peaks associated with oxygen-ion diffusion in the oxide-ion conductors La2−xBixMo2O9 (x=0.05, 0.1, and 0.15) have been studied. It is found that the activation energies of the two peaks increase with increasing Bi-doping concentration, which results from the blocking effects of the lone-pair…
We describe the production and characterization of a form of nanostructured carbon consisting of fully connected, three-dimensional (3D) sp2 networks. This form of carbon is characterized by interconnected thin layers forming a spongy structure with meso- and macroporosity. It is produced by a pulsed microplasma clust…
Star polymers with a high number of arms, f=263, become kinetically trapped when dispersed in an athermal solvent at concentrations above the overlapping one, forming physical gels. We show that the addition of linear chains at different concentrations and molecular weights reduces the modulus of the gel, eventually m…
Y 2 O 3 : Eu 3+ and Li-doped Y2O3:Eu3+ luminescent thin films have been grown on sapphire substrates using pulsed-laser deposition. The films grown under different deposition conditions have been characterized using microstructural and luminescent measurements. The photoluminescence (PL) brightness data obtained from…
Highly-ordered, single-domain (∼cm2), alumina nanopore arrays with controlled symmetry were obtained by anodizing prepatterned aluminum films that were deposited on silica substrates. Holographic lithography, in conjunction with a conformal deposition process, was utilized to form nanoscale corrugations on aluminum fi…
Quaternary Heusler alloy Ni2(Mn,Fe)Ga has been studied systematically for the structure, martensitic transformation, and magnetic properties in two systems of Ni50.5Mn25−xFexGa24.5 and Ni50.4Mn28−xFexGa21.6. Substituting Fe for Mn up to about 70%, the pure L21 phase and the thermoelastic martensitic transformation sti…