Materials Literature
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The contour integration technique applied to calculate the optical conductivity tensor at finite temperatures in the case of layered systems within the framework of the spin-polarized relativistic screened Korringa-Kohn-Rostoker band structure method is improved from the computational point of view by applying the Gau…
We show that the observed transition from rock salt to orthorhombic P(nma) symmetry in CrN can be understood in terms of stress anisotropy. Using local spin density functional theory, we find that the imbalance between stress stored in spin-paired and spin-unpaired Cr nearest neighbors causes the rock-salt structure t…
The contour integration technique applied to calculate the optical conductivity tensor at finite temperatures in the case of inhomogeneous surface layered systems within the framework of the spin-polarized relativistic screened Korringa-Kohn-Rostoker band structure method is extended to arbitrary polarizations of the…
In tunnel junctions of which at least one side is a ferromagnet, very large magnetic polarization change ($\approx 0.1 μ_B$) and splitting of the spin up and spin down Fermi energy ($\approx 0.1 eV$) can be created under steady state finite current conditions (bias voltage $\approx$ 1 volt). This is {\bf much higher}…
We investigate the coupling between individual tubes in a rope of single-wall carbon nanotubes using four probe resistance measurements. By introducing defects through the controlled sputtering of the rope we generate a strong nonmonotonic temperature dependence of the four terminal resistance. This behavior reflects…
Using first-principles total energy calculations, we have investigated the structure and phase stability of spinel-based transition aluminas $(\ensuremath{\gamma},\ensuremath{\delta},\ensuremath{\eta}),$ both in the presence and absence of hydrogen. The spinel-based structures (formed from dehydration of aluminum hydr…
We find that the electronic dispersion in graphite gives rise to double resonant Raman scattering for excitation energies up to 5 eV. As we show, the curious excitation-energy dependence of the graphite D mode is due to this double resonant process resolving a long-standing problem in the literature and invalidating r…
A transmission-type nonmechanical multiple-angle beam-steering device that uses liquid-crystal blazed grating has been developed. Sixteen steering angles with a contrast ratio of 18 has been demonstrated. A detailed analysis of the liquid-crystal and poly(methyl methacrylate) blazed-grating deflector was carried out t…
We consider a system of trimers and monomers on the triangular lattice, which describes the adsorption problem on (111) $1 \times 1$ surface of diamond structure. We give a mapping to a 3-state vertex model on the square lattice. We treat the problem by the transfer-matrix method combined with the density-matrix algor…
Attenuated total reflection Fourier transform infrared studies of the electrochemical redox processes of poly(dithieno[3,4-b:2‘,3‘-d]thiophene) (pDTT3), a low band gap conjugated polymer with a “polythiophene-like” backbone, where an aromatic moiety is fused to each thiophene ring, are reported. Vibrational spectrosco…
The promoting roles of noble metals (Pt, Rh, and Pd) and NO x storage mechanism were investigated on alkaline earth metal oxide-based NO x storage catalysts under lean-burn conditions. It was found that noble metals increased the reaction rates of NO oxidation to NO 2 and nitrite oxidation to nitrate, resulting in an…
Two models based on electrooptical parameters and one model using the fixed-charge approximation are tested for the calculation of the infrared intensities of the vibrational modes deduced from molecular dynamics calculations of four siliceous zeolites: sodalite, faujasite, zeolite A, and silicalite. The best results…
Porous titania microspheres with a very narrow particle size distribution (PSD) were synthesized by polymerization-induced colloid aggregation (PICA). After being sintered, the titania microspheres that are obtained have an average diameter of 3.5 microm, a surface area of 36.7 m2/g, an average pore volume of 0.30 mL/…
Using Au nanoparticles, it is possible under certain experimental conditions to considerably enhance the sensitivity of a conventional surface plasmon resonance (SPR) device. In this report, we examine the mechanism of this enhancement and discuss the experimental factors that are crucial to the performance of such a…
The fabrication of magnetic composite core−shell particles and hollow spheres with tailored dimensions and compositions has been accomplished by a multistep (layer-by-layer) strategy. Composite particles were prepared by coating submicrometer-sized anionic polystyrene (PS) latices with magnetite (Fe 3 O 4 ) nanopartic…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFormation of High-Quality CdTe, CdSe, and CdS Nanocrystals Using CdO as PrecursorZ. Adam Peng and Xiaogang PengView Author Information Department of Chemistry and Biochemistry University of Arkansas, Fayetteville, Arkansas 72701 Cite this: J. Am. Chem. Soc. 2001, 123,…
Variable-temperature synchrotron x-ray powder diffraction data from dehydrated Na6[Al6Si6O24] reveal a structural phase transition that involves both the commensurate ordering of the extra-framework Na cations and a one-dimensional incommensurate modulation of the framework. Peak splittings and superlattice reflection…
Polypropylene hollow fibers were produced via the spunbonding process. Nitrogen gas was used as the lumen fluid. The polypropylene continuity equation can be combined with the nitrogen continuity equation to give excellent predictions of the inside diameter and the outside diameter of the product fiber. Tests were dev…
We have reported previously on the expression of recombinant human type X collagen (hrColX) in HEK 293 and HT 1080 cells by using the eukaryotic expression vector pCMVsis (in which CMV stands for cytomegalovirus). Several stably transfected clones secreted full-length triple-helical hrColX molecules in large amounts,…
A method is presented for modeling the geometrical packing of polydisperse mixtures of both spherical and nonspherical particles, which are models for filler particles used in the manufacture of polymer composites. The technique is based on the calculation of the dissipative dynamics of an ensemble of fused soft spher…