Materials Literature
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We calculate the electronic structure for a modulation doped and gated T-shaped quantum wire using density functional theory. We calculate the bandgap renormalization as a function of the density of conduction band electrons, induced by the donor layer and/or the gate, for the translationally invariant wire, incorpora…
Emission and excitation spectra and luminescence decay curves of enstatite MgSiO 3 single crystals nominally doped with Ni and Cr have been measured at temperatures down to 10 K. For all the crystals under investigation, the emission band peaking at about 1520 nm is assigned to the 3 T 2 3 A 2 transition of octahedral…
The hydrogen uptake of asymmetric Fe/V (001) superlattices with L Fe / L V = 3/16 monolayers and 3/10 monolayers was investigated by resistometric methods. The hydrogen distribution and the enthalpy of solution were simulated using a diffusion model and calculated H-H interaction energies. It was found that the strain…
Nanocrystalline β-SiC was successfully synthesized at 600 °C through a new rapid reduction−carbonization route, in which metallic Na was used as the reductant, and activated carbon and tetrachlorosilane (SiCl 4 ) were used as source materials. X-ray powder diffraction indicates that β-SiC with high crystallinity is ob…
Ordered porous materials were produced from macrocrystalline emulsion templates. The templates were prepared by a repeated fractionation technique from polydisperse aqueous and nonaqueous emulsions with a drying control chemical additive. The aqueous emulsion drops tended to migrate and floc in relatively mobile local…
Neutron powder diffraction results on the tetragonal-orthorhombic and orthorhombic-monoclinic structural phase transitions of tungsten oxide are reported. The observed first-order transition from P 4/ ncc to Pnma at 980 K to 1200 K hides the transition from the higher-temperature phase P 4/ nmm (via Cmca ) to Pnma . A…
The title compound contains a three-coordinate Cu + ion bonded to the sulfonamide nitrogen atom and to two CO ligands with long Cu−C bonds (1.90 and 1.91 Å) and a C−Cu−C bond angle of 122°. The two ν(CO) IR bands for this compound are at 2158 (s) and 2184 (m) cm - 1 .
From fine-structure investigations it is well known that in many icosahedral boron-rich solids the occupation densities of specific atomic sites are considerably reduced. Investigations of the electronic properties have proved that the electronic properties of these semiconductors are strongly influenced by high densi…
We derive a model for voltage-induced wetting, so-called electrowetting, from the principle of virtual displacement. Our model includes the possibility that charge is trapped in or on the wetted surface. Experimentally, we show reversible electrowetting for an aqueous droplet on an insulating layer of 10 micrometer th…
In a recent paper by Jones et al., it is argued, based on FP-LAPW band-structure calculations, that previous calculations of ground-state properties for actinides, using the FP-LMTO method implemented by J. M. Wills, are in error. We demonstrate in this paper that the conclusions of Jones et. al. are unfounded. Calcul…
In order to examine the scratching resistance of ultrathin hydrogenated amorphous carbon (a-C:H) coatings used in magnetic storage devices, a large number of scratches with reproducible residual groove depths well below 1 nm has been examined. All measurements were carried out with an atomic force microscope and diamo…
Authors designed the monomers having hetero-aromatic rings in their structures as optical materials of high refractive index. Among various hetero-aromatics, we noticed thiophene has a large atomic refraction. We synthesized novel mono- and bi-functional thiophene methacrylate derivatives. Their homopolymers had high…
This letter introduces the concept of a thermoelectromechanical cooler (TEMC), which modifies a traditional thermoelectric cooler (TEC) by using intermittent contact of a mechanical element synchronized with an applied pulsed current. Using Bi2Te3 as the thermoelectric material, it is predicted that the maximum temper…
The substitutions of rare earths for La on the magnetic properties of the perovskites La0.7−xRxA0.3MnO3 (0<x<0.7), R=Pr or Gd and A=Ca, Sr, or Ba have shown that small substitution of Pr slightly increases the coercive field Hc and magnetization M, and strongly improves the magnetoresistance (MR) while l…
In this letter, we report on the switching properties of an ordered system of Bi4Ti3O12 ferroelectric memory cells of an average lateral size of 0.18 μm formed via a self-assembling process. The ferroelectricity of these cells has been measured microscopically and it has been demonstrated that an individual cell of 0.…
We describe a simple, yet phenomenologically very different, low-temperature modification to the conventional metal–organic chemical vapor deposition. It has been applied to the epitaxy of hexagonal-phased Bi2Te3/Sb2Te3 superlattices on zinc-blende GaAs substrates. The modification enables a two-dimensional, layer-by-…
Patterned growth of freestanding carbon nanotube(s) on submicron nickel dot(s) on silicon has been achieved by plasma-enhanced-hot-filament-chemical-vapor deposition (PE-HF-CVD). A thin film nickel grid was fabricated on a silicon wafer by standard microlithographic techniques, and the PE-HF-CVD was done using acetyle…
In this article, the curing kinetics of two fast cure flip-chip epoxy encapsulants under both isothermal and nonisothermal conditions are investigated by differential scanning calorimetry. The method allows determination of the most suitable kinetic model and corresponding parameters. The kinetic analysis suggests tha…
Ring-opening polymerization of ε-caprolactone (CL) has been initiated with rare earth phenyl compounds in both bulk and solution. These rare earth phenyl initiators can give polycaprolactone (PCL) with high yield and high molecular weight. The polymerization mechanism is through a coordination-deprotonation-insertion…
Vein grafts are subject to increased tensile stress due to exposure to arterial blood pressure, which has been hypothesized to induce endothelial cell (EC) and smooth muscle cell (SMC) injury. This study was designed to verify this hypothesis and to develop a tissue engineering approach that can be used to prevent the…