Materials Literature
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The electronic properties of doped bilayer graphene in presence of bottom and top gates have been studied and characterized by means of density-functional theory (DFT) calculations. Varying independently the bottom and top gates it is possible to control separately the total doping charge on the sample and the average…
In 1955 Fermi, Pasta, and Ulam showed that a simple model for a nonlinear one-dimensional chain of particles can be nonergodic, which implied infinite thermal conductivity. A more recent investigation of a realistic model for an individual polyethylene chain suggests that this phenomenon can even persist in real polym…
The generator-coordinate method is a flexible and powerful reformulation of the variational principle. Here we show that by introducing a generator coordinate in the Kohn-Sham equation of density-functional theory, excitation energies can be obtained from ground-state density functionals. As a viability test, the meth…
We report first principles density functional calculations of electronic structures and energy bandgaps ($ΔE_g$) in PbS nanowires (NW). The $ΔE_g$ is tuned by varying the diameter of the NW - {\it revealing the role of quantum confinement}. The compressive radial strain (CS) on the NW is shown to be responsible for se…
We demonstrate that the peak in the density dependence of electron spin relaxation time in $n$-type bulk GaAs in the metallic regime predicted by Jiang and Wu [Phys. Rev. B {\bf 79}, 125206 (2009)] has been realized experimentally in the latest work by Krauß{\em et al}. [arXiv:0902.0270].
We have synthesized tetragonal iron selenide and telluride superconductors through solid state reaction at 450deg.C and 550deg.C respectively. These synthesis temperatures have been established by optimization. Electrical resistivity and magnetic susceptibility measurements (4.2-300 K) confirm superconductivity with T…
The introduction of carbon nanotubes (CNTs) into nonconducting polymers has been observed to yield orders of magnitude increases in conductivity at very low concentrations of CNTs. These low percolation concentrations have been attributed to both the formation of conductive networks of CNTs within the polymer and to a…
Short randomly oriented banana and sisal hybrid fiber reinforced polyester composites, banana/polyester composites and sisal/polyester composites were fabricated at different fiber loading say, 0.20 to 0.50 V f . Composites were prepared by varying the relative volume fraction of the two fibers at each fiber loading.…
Using propagating plasmons on silver nanowires as an excitation source we perform surface-enhanced Raman scattering (SERS) at a nanoparticle/wire junction located remotely from the laser illumination spot with sensitivities in a few molecules range. Simultaneous multisite remote-excitation SERS sensing can also be ach…
Light aqueduct: Periodic mesoporous organosilica exhibits strong light absorption due to densely packed organic chromophores within the pore walls. Light energy absorbed by 125 biphenyl groups in the pore walls is funneled into a single coumarin 1 molecule in the mesochannels with almost 100% quantum efficiency, and r…
We report intracellular fluorescence lifetime imaging (FLIM) and fluorescence anisotropy measurements of two meso-substituted fluorophores based on the boron−dipyrrin (BODIPY) structure. Both dyes incorporate hydrophobic groups, which render them membrane-soluble. We have obtained values for quantum yields, radiative…
We report a thermoelectric study of graphene in both zero and applied magnetic fields. As a direct consequence of the linear dispersion of massless particles, we find that the Seebeck coefficient Sxx diverges with 1/sqrt[|n_{2D}|], where n_{2D} is the carrier density. We observe a very large Nernst signal S_{xy} ( app…
Spiral yarn composed with an elastomeric filament DOW XLA, from Dow Chemical, and wool fibres outwardly wound around the elastic core presents a complex behaviour when wound on bobbins to be dyed. This article presents a basic mathematical model with the aim of evaluating radial pressure and transversal stress on bobb…
Measurements of the radial breathing modes from Raman Spectroscopy have been most useful in characterizing the diameters of single-wall carbon nanotubes (SWNT), where there is a simple monotonic relationship between frequency and diameter. Similar correlations have also been used to predict sizes for double and multip…
Materials in the Na 1− x Sr x /2 ◻ x /2 NbO 3 system (0.3 ≤ x ≤0.4) have been investigated by combining diffraction methods and high resolution electron microscopy with dielectric measurements. They undergo a microstructural evolution by continuously decreasing the coherent structural domain size as a consequence of t…
We report on a novel method based on a plasma pretreatment for controlled nanostructuration and patterning of iron catalyst particles from a continuous film in view of carbon nanotube growth. The effects of the hydrogen plasma conditions on the diameter and the density of the catalyst nanoparticles was studied and dis…
The importance of the role of alkane solvents in the self-assembly process of pi-conjugated molecules is well recognized but hardly understood. Here we present our results on the X-ray diffraction studies that we conducted to gain insight into the supramolecular structure of mixtures of a bipyridine-based molecule (1)…
Model-free kinetic approaches were employed to investigate the combustion kinetics of coals with different ranks, namely, lignite, bituminous coal, and anthracite. The experimental data were provided under non-isothermal conditions at different heating rates in the range of 2–25°C min−1. The activation energy values w…
A 65-year-old female with biopsy-confirmed nephrogenic systemic fibrosis (NSF) received a kidney transplantation. Despite good kidney function, her symptoms continued to progress. Deferoxamine was administered intramuscularly at 500 mg/day and later 1000 mg/day after 1 week with no adverse effects. Urine excretion of…
Co nanowire arrays with diameters of 20 and 50 nm are fabricated into anodic aluminium oxide templates by the ac electrodeposition technique. The coercivity of nanowire arrays with diameter of 50 nm is 1990 Oe, whereas that of nanowire arrays with diameter of 20 nm is only 925 Oe. This is quite different from earlier…