Materials Literature
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We investigate the role of electron-phonon scattering and gate bias in degrading the drive current of nanotube MOSFETs. Our central results are: (i) Optical phonon scattering significantly decreases the drive current only when gate voltage is higher than a well-defined threshold. It means that elastic scattering mecha…
A novel magnetic resonance imaging (MRI) thermometry technique is demonstrated in vitro based upon the use of a PARACEST (PARAmagnetic Chemical Exchange Saturation Transfer) agent. This new method takes advantage of the high concentration of bulk water (the readout signal for imaging) and the hyperfine frequency shift…
We present analytical results and kinetic Monte Carlo simulations for the mobility and microscopic structure of solid-on-solid (SOS) interfaces driven far from equilibrium by an external force, such as an applied field or (electro)chemical potential difference. The interfaces evolve under a specific stochastic dynamic…
Charge transport in semiconducting single-walled nanotubes (SWNTs) with Schottky-barrier contacts has been studied at high bias. We observe nearly symmetric ambipolar transport with electron and hole currents significantly exceeding 25 microA, the reported current limit in metallic SWNTs due to optical phonon emission…
The dispersion interaction between two point-like particles confined in a dielectric slab between two plates of another dielectric medium is studied within a continuum (Lifshitz) theory. The retarded (Casimir-Polder) interaction at large inter-particle distances is found to be strongly enhanced as the mismatch between…
Surface-bound modes in metamaterials forged by drilling periodic hole arrays in perfect-conductor surfaces are investigated by means of both analytical techniques and rigorous numerical solution of Maxwell's equations. It is shown that these metamaterials cannot be described in general by local, frequency-dependent pe…
Using density functional theory, we demonstrate that superconductivity in ${\mathrm{C}}_{6}\mathrm{Ca}$ is phonon mediated with $\ensuremath{\lambda}=0.83$ and phonon frequency $⟨\ensuremath{\omega}{⟩}_{\mathrm{log}}=24.7\text{ }\text{ }\mathrm{meV}$. The calculated isotope exponents are $\ensuremath{\alpha}(\mathrm{…
The energy-level alignment at interfaces between three electroactive conjugated organic materials and Au was systematically varied by adjusting the precoverage of the metal substrate with the electron acceptor tetrafluoro-tetracyanoquinodimethane (F4-TCNQ). Photoelectron spectroscopy revealed that electron transfer fr…
We demonstrate the key role of phonon occupation in limiting the high-field ballistic transport in metallic carbon nanotubes. In particular, we provide a simple analytic formula for the electron transport scattering length, which we validate by accurate first principles calculations on (6, 6) and (11, 11) nanotubes. T…
The energies of point defects in graphite have been calculated from first principles. The various interplane interstitial configurations are found to have a wider range of energies than in some earlier calculations, implying a larger interstitial migration energy than previously expected $(>1.5\phantom{\rule{0.3em}…
Glasses have a large excess of low-frequency vibrational modes in comparison with most crystalline solids. We show that such a feature is a necessary consequence of the weak connectivity of the solid, and that the frequency of modes in excess is very sensitive to the pressure. We analyze, in particular, two systems wh…
To understand the formation mechanism of magnetic moments at the edges of graphitic fragments, we carry out first-principles density-functional calculations for the electronic and magnetic structures of graphitic fragments with various spin and geometric configurations. We find that interedge and interlayer interactio…
In this work a simple concept was used for a systematic search for materials with high spin polarization. It is based on two semiempirical models. First, the Slater-Pauling rule was used for estimation of the magnetic moment. This model is well supported by electronic structure calculations. The second model was found…
The synthesis of TlGa 1− x Yb x S 2 single crystals with the partial substitution of ytterbium for gallium is described. Variations in the electric conductivity of grown crystals irradiated with X-rays of various intensities are measured.
Around the year 1500, Leonardo da Vinci designed the first mechanical calculator connecting a number of toothed wheels for simple adding operations. Since then, mechanical systems have become a major part of the later industrial revolutions with an abundance of machines in our everyday lives. Only with the advent of s…
A new sucrose ester, acretoside, has been isolated from the roots of the Greek endemic species Aristolochia cretica and identified as 6-O-p-coumaroyl-beta-D-fructofuranosyl-(2 --> 1)-alpha-D-glucopyranoside (1). In addition, a known sucrose ester, identified as arillatose B, two phenylpropanoid glucose esters, and fiv…
Abstract We have prepared nanocomposites of intercalated and exfoliated organosilicates in butadiene rubber (BR) by using a two‐stage melt blending process. We used X‐ray diffraction and transmission electron microscopy to examine, respectively, the intergallery spacing of the organosilicates and their dispersion in t…
This work aimed at studying the electrochemical reduction of the hexavalent chromium Cr(VI) by means of a tubular reactor operating under both continuous and batch regimes. It is shown that chromium (VI) reduction to chromium (III) was exerted not only by the oxidation of iron to Fe(II) released from the steel sacrifi…
Abstract Facile antimony(V/III) transition has been found to occur in phthalocyanine complexes via oxidative addition/reductive elimination process.
An antiparallel orientational transition is reported for an intermetallic compound, i.e., ${\mathrm{Cd}}_{6}\mathrm{Ca}$ crystal, which is a $1∕1\ensuremath{-}1∕1\ensuremath{-}1∕1$ crystalline approximant to the icosahedral quasicrystal ${\mathrm{Cd}}_{5.7}\mathrm{Ca}$. A group theoretical analysis based on the Landau…