Materials Literature
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Carbon nanocoils with a coil diameter of 50–450 nm were prepared by the catalytic pyrolysis of acetylene, and the preparation conditions and morphology were examined. To clarify the growth mechanism, the carbon nanocoils were also heat treated at 2500 °C for 8 h in a N2 atmosphere, then partially oxidized in air at 60…
We present a combined density functional theory and EXAFS investigation into the geometry and coordination of the oxygen-donating species in surface grafted, tert-butyl hydroperoxide (TBHP) exposed Ti↑MCM-41 oxidation catalysts. The formation of a number of different Ti(η2-peroxo) and Ti(η1-peroxo) type species, inclu…
We report that low-intensity light can dramatically influence and regulate the nanoparticle self-assembly process: Illumination of a substrate exposed to a beam of gallium atoms results in the formation of gallium nanoparticles with a relatively narrow size distribution. Very low light intensities, below the threshold…
The pressure-induced insulator-metal transition in amorphous ${\mathrm{GeSe}}_{2}$ $(a\ensuremath{-}{\mathrm{GeSe}}_{2})$ is studied using an ab initio constant pressure molecular-dynamic simulation. $a\ensuremath{-}{\mathrm{GeSe}}_{2}$ transforms gradually to an amorphous metallic state under the application of press…
The glass-forming ability, thermal stability, and magnetic properties have been investigated for an Fe67Co9.4Nd3.1Dy0.5B20 glassy alloy with a large supercooled liquid of 48 K before crystallization prepared by copper mold casting. The glassy phase is formed in a rod form with a diameter of 0.5 mm. The crystallized na…
The layered trirutile phases HMWO6 (M = Nb, Ta) and the layered perovskite H2W2O7 (synthesized by acid leaching of Bi2W2O9) were exfoliated into nanoscale colloids by reaction with quaternary ammonium hydroxides.
The development of self-assembled magnetic CoFe2O4 nanoparticles within polymer matrices at room temperature is reported. Diblock copolymers consisting of poly (norbornene) and poly (norbornene-dicarboxcylic acid) (NOR/NORCOOH) were synthesized. The self-assembly of the mixed metal oxide within the NORCOOH block was a…
Abstract A series of new shape memory polymers are synthesized by the cationic copolymerization of regular soybean oil, low saturation soybean oil (LoSatSoy oil), and/or conjugated LoSatSoy oil with styrene and divinylbenzene, norbornadiene, or dicyclopentadiene initiated by boron trifluoride diethyl etherate or relat…
The ability of surface passivation to enhance the photoluminescence (PL) emission of Si nanocrystals in SiO2 has been investigated. No significant increase of the average nanocrystal size has been detected for annealings at 1100 °C between 1 min and 16 h. In contrast, the PL intensity steadily increases and reaches sa…
<div class="htmlview paragraph">As demand for wall-flow Diesel particulate filters (DPF) increases, accurate predictions of DPF behavior, and in particular of the accumulated soot mass, under a wide range of operating conditions become important. This effort is currently hampered by a lack of a systematic knowle…
Ab initio cluster and supercell methods are used to investigate the local geometry and optical properties of hydrogen defects in diamond. For an isolated impurity, the bond-centered site is found to be lowest in energy, and to possess both donor and acceptor levels. The neutral defect possesses a single local mode wit…
Magnetization reversal in magnetic nanostructures is investigated numerically over time-scales ranging from fast switching processes on a picosecond scale to thermally activated reversal on a microsecond time-scale. A simulation of the stochastic Landau-Lifshitz equation of motion is used as well as a time quantified…
We have investigated the swelling of acetone in fluorocarbon polymer films doped with different gold concentrations below the percolation threshold. The presence of the gold clusters in the polymer improves the mixing between the polymer and the acetone, which is not a good solvent for this kind of polymer. To explain…
<div class="htmlview paragraph">As legislation tightens in the Heavy Duty Diesel (HDD) area it is essential to develop systems with high activity and excellent durability for both Particulate Matter (PM) and NOx control. The Continuously Regenerating Trap (CRT™) system controls hydrocarbon (HC), CO and PM emissi…
We introduce a general Monte Carlo scheme for achieving atomistic simulations with monoelectronic Hamiltonians including the thermalization of both nuclear and electronic degrees of freedom. The kinetic Monte Carlo algorithm is used to obtain the exact occupation numbers of the electronic levels at canonical equilibri…
We have grown (InyGa1−y)1−xMnxAs ferromagnetic semiconductor layers with Mn composition of x up to 0.13 on InP substrates by molecular beam epitaxy. Near the lattice-matched composition, i.e., y∼0.53, the Curie temperature increases linearly with the ferromagnetically effective Mn composition xeff, following the empir…
A fourteen-fold anisotropy in the spin transport efficiency parallel and perpendicular to the charge transport is observed in a vertically biased (Ga, Mn)As-based spin-polarized light emitting diode. The spin polarization is determined by measuring the polarization of electroluminescence from an (In, Ga)As quantum wel…
Single-crystal CaAl2O4 fibers doped with Ce3+ or Tb3+ or double doped with Tb3+ and Ce3+ were prepared by the laser-heated pedestal-growth method. Ce3+-doped CaAl2O4 was found to have persistent phosphorescence in the blue violet lasting more than 10 h, while Tb3+-doped CaAl2O4 showed only a weak afterglow. However, l…
Although autogenous saphenous vein remains the standard for coronary and infrapopliteal bypass, many patients do not have a suitable vein. Attempts at developing a small-caliber vascular graft have failed largely due to occlusion, neointimal hyperplasia, or aneurismal degradation. We have designed and characterized a…
Aligned MWNT–PPy composite films show exceptional charge storage capacities and improved response times. The superior performance of these composites, compared to pure PPy films, is demonstrated and discussed. The Figure shows an SEM image of the fractured film cross section, illustrating the thickness of the PPy coat…