Materials Literature
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With their interesting electrical, structural, and physical properties, carbon nanotubes (CNTs) are envisioned to impact future nanoelectronics, nanosensors, and nanophotonics. Current research and development efforts in the growth of CNTs rely on the time-consuming one-parameter-at-a-time approach, whereby marginal v…
CaWO 4 phosphor films doped with rare-earth ions (Eu 3+ , Dy 3+ , Sm 3+ , Er 3+ ) were prepared by the Pechini sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis, atomic force microscopy, and photoluminescence spectra, as well as lifet…
The perovskite La 1/3 Sr 2/3 FeO 3−δ was investigated by neutron diffraction, magnetic and Mössbauer spectroscopy measurements. La 1/3 Sr 2/3 FeO 3−δ undergoes magnetic ordering at T = 190–200 K accompanied by charge disproportionation. Magnetic peaks due to charge ordering are observed below 200 K. The charge orderin…
Recent studies of zirconium tungstate, ${\mathrm{ZrW}}_{2}{\mathrm{O}}_{8},$ show an isotropic negative thermal expansion (NTE) over a wide temperature range. It has been proposed that the low-energy phonon vibrational modes, observed in both specific heat and phonon density-of-states measurements, are responsible for…
We report, in this letter, a simple thermal oxidation approach to growing large-scale arrays of aligned tungsten oxide nanorods on planar substrates. By passing a current of ∼50 A through a tungsten spiral coil in a vacuum of ∼3 × 10 −2 Torr, single-crystalline WO 2.9 nanorods, ∼20 nm in diameter and ∼400 nm long, wer…
We report on the nucleation and growth of tetracene in a thin liquid film which is continuously supersaturated by vapor deposition of molecules onto the film. In a first stage, nucleation and fast anisotropic two-dimensional dendritic growth occurs. In a second stage, the dendrites coarsen into pallet-shaped crystals.…
In this work, we investigated the mechanism involved in the photoinitiated cross-linking of the polyester poly(propylene fumarate) (PPF) using the initiator bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide (BAPO). It was hypothesized that BAPO has the ability to cross-link PPF into solid polymer networks, without the…
This Communication reports a low-temperature diamond synthesis technique, in which diamonds (10-250 mum) can form at a temperature as low as 440 degrees C by reduction of dense CO2 with metallic Na. The X-ray diffraction pattern of a powder sample shows three reflection peaks, indexed with 111, 220, and 311, correspon…
Traditional pictures of optical properties in phenylacetylene dendrimers view the molecule as a collection of independent chromophores, linked by meta-substitution at the central phenyl ring. While this picture is reasonable for explaining the observed absorption trends, it breaks down in describing the emission behav…
We establish a strict correlation between the total photoelectron yield spectra and the surface conductivity of hydrogenated diamond. The decomposition of the yield spectra into electron and exciton derived contributions requires an upward surface band bending to accompany surface conductivity, while an essentially fl…
Fluorescent colloidal particles, fabricated by depositing a thin gold film on one side of the particle, show intensity fluctuation (blinking) under an optical microscope because of their rotational Brownian motion. Interactions between molecules immobilized on the surfaces of the particle and the solid substrate restr…
Medical ultrasound is a highly valuable diagnostic tool, especially when compared with other imaging modalities. It is a noninvasive, real-time, portable, extremely safe method compared with X-ray and inexpensive relative to magnetic resonance imaging. However, ultrasound is limited in its ability to distinguish betwe…
Collagen is the most abundant protein in animals. Natural collagen consists of a triple helix of (Xaa-Yaa-Gly)n chains, in which the Xaa and Yaa residues are often l-proline. Here, a (2S,4S)-4-fluoroproline (flp) residue is shown to be greatly stabilizing in the Xaa position (but destabilizing in the Yaa position). In…
Characteristic fluorescence properties of photochromic 1,2-bis(3-methyl-2-thienyl)perfluorocyclopentene were studied in solution as well as in the single-crystalline phase. When the concentration of 1,2-bis(3-methyl-2-thienyl)perfluorocyclopentene was increased in a 3-methylpentane solution, the fluorescence spectrum…
Polycrystalline samples of the partially filled skutterudites Nd x Co 4 Sb 12 have been prepared and characterized by x-ray powder diffraction and differential thermal analysis. The saturation limit of the Nd void filling in CoSb 3 was found to be around 13%. All samples decompose incongruently at a temperature of 114…
The electronic structure and optical properties of metallic nanoshells are investigated using a jellium model and the Time Dependent Local Density Approximation (TDLDA). An efficient numerical implementation enables applications to nanoshells of realistic size with up to a million electrons. We demonstrate how a frequ…
The ferromagnetic transition in a diluted magnetic semiconductor with localized charge carriers is inevitably a percolation transition. In this work we theoretically study the correlation between this magnetic percolation and transport properties of the sample, including the possibility of a simultaneous transport per…
We analyze solid-state phase transformations that occur in zinc-sulfide crystals during annealing using a random deformation-faulting mechanism with a very simple interaction between adjacent close-packed double layers. We show that, through annealing, infinite-range structures emerge from initially short-range crysta…
The exploitation of the spin in charge-based systems is opening revolutionary opportunities for device architecture. Surprisingly, room temperature electrical transport through magnetic nanowires is still an unresolved issue. Here, we show that ferromagnetic (Co) suspended atom chains spontaneously display an electron…
Using a set of evolution equations [J.G. Amar {\it et al}, Phys. Rev. Lett. {\bf 86}, 3092 (2001)] for the average gap-size between islands, we calculate analytically the asymptotic scaled capture-number distribution (CND) for one-dimensional irreversible submonolayer growth of point islands. The predicted asymptotic…