Materials Literature
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We have measured the photoconductivity excitation spectra of individual semiconducting carbon nanotubes incorporated as the channel of field-effect transistors. In addition to the pronounced resonance that correlates with the second van Hove transition (E(22)) in semiconducting carbon nanotubes, a weaker sideband at a…
Abstract For Abstract see ChemInform Abstract in Full Text.
Intrinsic catalytic process by capillary condensation of Ga-atoms into nanotrenches, formed among impinging islands during the wurzite-GaN thin film deposition, is shown to be an effective path to growing GaN nanorods without metal catalysts. The nano-capillary brings within it a huge imbalance in equilibrium partial…
We report on electrical spin injection measurements on multiwall carbon nanotubes (MWNTs). We use a ferromagnetic alloy Pd1−xNix with x≈0.7 which allows us to obtain devices with resistances as low as 5.6kΩ at 300 K. The yield of device resistances below 100kΩ, at 300 K, is around 50%. We measure at 2 K a hysteretic m…
Oily core polyurethane nanocapsules with a mean diameter of 200 nm were formulated in miniemulsion by interfacial polycondensation. The encapsulation process in miniemulsion was optimized by the choice of the surfactant type (anionic, cationic, or nonionic) and concentration; hexadecane was the costabilizer. Size dist…
Acidic proteins from many biogenic minerals are implicated in directing the formation of crystal polymorphs and morphologies. We characterize the first extremely acidic proteins purified from biomineralized aragonite. These abalone nacre proteins are two variants of 8.7 and 7.8 kDa designated AP8 (for aragonite protei…
We investigate the interaction effect between oxygen impurities in crystalline germanium on the basis of a quantum rotor model. The dipolar interaction of nearby oxygen impurities engenders non-trivial low-lying excitations, giving rise to anomalous behaviors for oxygen-doped germanium (Ge:O) below a few degrees Kelvi…
Temperature-dependent x-ray diffraction of the low-dimensional spin 1/2 quantum magnet TiOCl shows that the phase transition at T_{c2} = 90 K corresponds to a lowering of the lattice symmetry. Below T_{c1} = 66 K a twofold superstructure develops, that indicates the formation of spin-singlet pairs via direct exchange…
We have examined the effects of 20 keV electron irradiation on [-Cu(1)-O(1)-]n chain oxygen arrangements in oxygen deficient but otherwise twin-free YBa2Cu3O6+x single crystals. Comparison of polarized Raman spectra of non-irradiated and irradiated areas provides evidence that electron bombardments instigate the colle…
We present calculations of magnetic exchange interactions and critical temperature ${T}_{c}$ in ${\mathrm{G}\mathrm{a}}_{1\ensuremath{-}x}{\mathrm{M}\mathrm{n}}_{x}\mathrm{A}\mathrm{s}$, ${\mathrm{G}\mathrm{a}}_{1\ensuremath{-}x}{\mathrm{C}\mathrm{r}}_{x}\mathrm{A}\mathrm{s}$, and ${\mathrm{G}\mathrm{a}}_{1\ensuremath…
A multidomain two-dimensional periodically poled ferroelectric plate vibrator is reported for the first time. The theoretical calculations, computer simulations by the Finite Element Method and experimental data from the lithium tantalite samples reveal a domain acousto-electric resonance. A polarization inversion in…
GaN-nanorods grown on Si(111) substrates are found strain- and defect-free as characterized by micro Raman spectroscopy, secondary electron (SE) and cathode-luminescence (CL) imaging. The matrix supporting the nanorods bears the brunt of all strains, strain-relaxations, and defect generations, giving the nanorods an i…
Supramolecular chiral insulated molecular wire was constructed by self-assembly of a neutral one-dimensional schizophyllan host and a water-soluble polythiophene guest. The work presented here will not only open a door to a new application of polysaccharides but also provide an important clue to prepare stable supramo…
When two liquid drops come into contact, they coalesce rapidly, owing to the large curvature and unbalanced surface-tension forces in the neck region. We use an ultra-high-speed video camera to study the coalescence of a pendent and a sessile drop, over a range of drop sizes and liquid viscosities. For low viscosity,…
The magnetic modification of carbon nanotubes is described here. Pyrene can be noncovalently attached on the carbon nanotube surface. A carboxylic derivative of pyrene is used as interlinker for the binding of capped magnetic nanoparticles on the carbon nanotubes. The increased organophilic character of the capped nan…
We report that dendrimer-encapsulated Pd nanoparticles having a diameter of approximately 1.7 nm are effective and general catalysts for coupling aryl halides to organostannanes (the Stille reaction) under mild conditions. The significant results of this study are that the Stille reaction is catalyzed by dendrimer-enc…
The nonlinear response of infinite periodic solids to homogenous electric fields and collective atomic displacements is discussed in the framework of density functional perturbation theory. The approach is based on the $2n+1$ theorem applied to an electric-field-dependent energy functional. We report the expressions f…
Irreversible effects in thermoelectric materials limit their efficiency and economy for applications in power generation and refrigeration. While electron transport is unavoidably irreversible in bulk materials, here we derive conditions under which reversible diffusive electron transport can be achieved in nanostruct…
Ammonolysis of aliphatic and aromatic polycarbonates in liquid or in supercritical ammonia has been studied. Reaction products are alcohols (phenols) and urea. Ammonolysis of bisphenol A polycarbonate (BPA-PC) proceeds at room temperature at a high rate depending on the size and surface of particles. BPA-PC in composi…
Abstract We have investigated the defect structures and potential of mean force (PMF) of three colloidal spheres immersed in a nematic liquid crystal (for linear and equilateral‐triangular configurations), using a coarse‐grained theory for the tensor order parameter. At large separations, each sphere is surrounded by…