Materials Literature
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ZnO nanowires with diameters ranging from 20 to 60 nm and lengths in the range 5–15 μm were synthesized by metalorganic chemical vapor deposition, assisted by colloidal gold nanoparticles with a diameter of 20 nm dispersed on SiO2∕Si substrates. The ZnO nanowires were found to have a high-internal quantum efficiency a…
Adsorption of inorganic mercury(II) from an aqueous solution on mercaptopropyl-functionalized SBA-15 mesoporous silicas has been investigated. Adsorbents were prepared by the cocondensation method using tetraethoxysilane and different quantities of (mercaptopropyl)trimethoxysilane. Pluronic P123 was employed as a stru…
We calculate the electronic wave-function for a phosphorus donor in silicon by numerical diagonalisation of the donor Hamiltonian in the basis of the pure crystal Bloch functions. The Hamiltonian is calculated at discrete points localised around the conduction band minima in the reciprocal lattice space. Such a techni…
Current-induced switching from metallic to insulating state is observed in phase-separated states of (La_{1-y}Pr_y)_{0.7}Ca_{0.3}MnO_3 (y=0.7) and Nd_{0.5}Ca_{0.5}Mn_{1-z}Cr_zO_3 (z=0.03) crystals. Application of magnetic fields to this current-induced insulating state causes pronounced low-field negative magnetoresis…
The dispersion properties of rectangular metallic waveguides periodically loaded by uniaxial resonant scatterers are studied with help of an analytical theory based on the local field approach, the dipole approximation and the method of images. The cases of both magnetic and electric uniaxial scatterers with both long…
The current-induced magnetization dynamics of a spin valve are studied using a macrospin (single domain) approximation and numerical solutions of a generalized Landau-Lifshitz-Gilbert equation. For the purpose of quantitative comparison with experiment [Kiselev {\it et al.} Nature {\bf 425}, 380 (2003)], we calculate…
We study the double exchange in transition metal oxides with itinerant and localized electrons. We show that the charge transfer energy Delta and the oxygen-oxygen hopping amplitude t(pp) have a strong effect on magnetic ordering: while for Delta>0 the ground state is ferromagnetic, for negative Delta and large t(pp)…
The Berezinskii-Kosterlitz-Thouless (BKT) transition in two-dimensional planar rotator and XY models on a square lattice, diluted by randomly placed vacancies, is studied here using hybrid Monte Carlo simulations that combine single spin flip, cluster and over-relaxation techniques. The transition temperature $T_c$ is…
For solving the longstanding materials science problem of correlating elastic properties of a solid material to the formation of cracks we present a new general concept. This concept is applied to the technologically most important cracks of loading mode I for which we establish exact correlations by introducing a loc…
We analyze the modification of the intersubband absorption of electrons in quantum wells under intense THz irradiation. An expression for the induced current is obtained, based on the adiabatic approach and the resonant approximation. We predict the occurrence of a significant fine structure as well as the broadening…
Natural abundance, much higher strength per unit weight than most inorganic fillers, lower density and their biodegradable nature make natural fillers attractive as reinforcements of engineering polymer systems. However, certain drawbacks such as incompatibility with the hydrophobic polymer matrix, the tendency to for…
ADVERTISEMENT RETURN TO ISSUEPREVHighlights From Pate...Highlights From PatentsNEXTA Review of U.S. Patents in the Field of Organic Process Development Published during November and December 2004Keith TurnerView Author Information Kappa Tau Consulting, 12 The Avenue, Fairfield, Stockton-on-Tees, TS19 7EY, Telephone/fa…
We study the effect of open boundary condition on charge density waves (CDW). The electron density oscillates rapidly close to the boundary, and additional non-oscillating terms ( ∼ ln ( r )) appear. The Friedel oscillations survive beyond the CDW coherence length ( v F /Δ), but their amplitude gets heavily suppressed…
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Abstract Polypropylene (PP)/polystyrene (PS) blends modified with reactive monomers, such as maleic anhydride (MAH) and styrene (St), and in situ formed PP/PS blends were prepared by melting extrusion. The crystallization and melting behavior and the dynamic mechanical properties of the PP/PS blends, including the str…
A convenient one-step synthesis of silicon nanoparticles from thermal reduction of -di- tert -butyl-1, 3-diaza-2, 2-dichloro-2-silacyclopentane in the presence of trioctylphosphine oxide and Li metal is discussed. Transmission electron microscopy, energy dispersive x-ray analysis, UV/visible and IR spectroscopy, fluor…
In-situ high-pressure synchrotron angle-dispersive X-ray diffraction for gibbsite (aluminum trihydroxide) was performed at room temperature up to 20 GPa. A pressure-induced phase transition was observed at 2.6 GPa. The new high-pressure phase can be recovered at ambient pressure. Rietveld refinement shows that the new…
This study investigates complex salts of [PW(12)O(40)](3-), [PVW(11)O(40)](4-), [PV(2)W(10)O(40)](5-), and [PV(3)W(9)O(40)](6-) Keggin anions using Fourier transform infrared spectroscopy under ambient atmospheric and high-vacuum conditions and by computational methods. A detailed vibrational study suggests that the p…
The average interstitial nanopore structure of single-wall carbon nanohorn (SWNH) assemblies was determined using X-ray diffraction and grand canonical Monte Carlo (GCMC) simulation aided N(2) adsorption at 77 K. The interstitial nanopores of SWNH assemblies can be regarded as quasi one-dimensional pores due to the pa…
Abstract 2,6‐Dimethyl phenol dicyclopentadiene dicyanate ester (DCPDCY) was synthesized through the reaction of 2,6‐dimethyl phenol dicyclopentadiene novolac and cyanogen bromide. The proposed structure was confirmed by Fourier transform infrared, mass spectrometry, NMR spectrometry, and elemental analysis. DCPDCY was…