Materials Literature
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Two strong violet-blue luminescence emissions at 390 and 440 nm under excitation at room temperature have been observed in the ordered mesoporous zirconium oxide post-treated with phosphoric acid. The oxide was characterized by powder x-ray diffraction, nitrogen adsorption, diffuse reflectance UV-vis spectroscopy, x-r…
Nematic emulsions and polymer dispersed liquid crystals (PDLCs) are composite materials formed by micron-sized droplets of mesogenic molecules, which are embedded in fluid or solid matrices, respectively. Both systems can be switched from an opaque to a trasparent state by application of a suitable electric field. The…
The mean field theory proposed originally by Kubo and Ohata for manganites is generalized for a ferrimagnetic half-metal and applied to the magnetite. The relevance of both the double exchange interaction and the superexchange one for the spin ordering in the conducting B sublattice of magnetite is shown. The shortcom…
The phase behavior of a liquid-crystal forming model colloidal system containing hard rodlike and platelike particles is studied using the Parsons–Lee scaling [J. D. Parsons, Phys. Rev. A 19, 1225 (1979); S. D. Lee, J. Chem. Phys. 87, 4972 (1987)] of the Onsager theory. The rod and plate molecules are both modeled as…
The adsorption of hydrogen (deuterium) and oxygen on neutral platinum clusters has been investigated in a cluster beam experiment. The beam passes through two low-pressure reaction cells and the clusters, with and without adsorbed molecules, are detected by laser ionization and mass spectrometry. Both H2 and O2 adsorb…
In this letter, magnetization reversal is investigated in (Ga,Mn)As thin films using the magneto-optical Kerr effect. A Stoner–Wohlfart model, modified to take into account the existence of magnetic reversal discontinuities associated with nucleation and propagation phenomena allows us to estimate most of the characte…
The population change of the photoluminescence (PL) W center (or ${I}_{I}$ center) with 2-MeV electron irradiation in proton-implanted silicon crystal was observed to investigate the origin of the center. While a straightforward annihilation of the W centers formed by proton implantation with an increase of the electr…
The bonding of atomic oxygen to ferrous iron was studied using the Fe(OH)2 system as a model of the ferrous iron center. All lowest triple, quintet, and septet states of OFe(OH)2 were studied at the complete active-space self-consistent-field theory level augmented by multireference second-order-perturbation theory. I…
The structure and the shape of polymer droplets of nanoscopic size on ultrathin cylindrical fibers (with diameters in the range of nanometers) is investigated by Monte Carlo simulation of a coarse-grained bead-spring type model. The interaction between atoms in the solid nanocylinder and the effective monomers is assu…
We have studied the dynamical and structural properties of dense charge stabilized colloidal suspensions by a combination of small-angle neutron scattering (SANS), 3D dynamic light scattering (3DDLS) and diffusing wave spectroscopy (DWS). SANS and 3DDLS extend static and dynamic light scattering techniques to the regi…
The shock response of the aluminum alloy 7010-T6, induced by the technique of plate impact, has been investigated as a function of orientation to the loading axis to the rolling direction. Measurements of the Hugoniot elastic limit (HEL) and spall strength show that the material is stronger in the longitudinal orienta…
A new luminescent material, Sr3Al10SiO20:Eu2+, has been synthesized. The material exhibits an emission peak at 466 nm for the (Sr0.993Eu0.007)3Al10SiO20 and a CIE chromaticity of (x=0.145, y=0.124), with relative intensity of 60% of commercial phosphor BaMgAl10O17:Eu2+ under vaccum ultraviolet excitation.
Three important frontiers of ultrafast time-resolved macromolecular crystallography are presented: extension of this technique to other biological systems; further developments in the elucidation of mechanism through the analysis of time-dependent movies to extract the underlying, time-independent, intermediate struct…
A complex Langevin framework is described for carrying out numerical simulations of coupled field equations for flow and structure of inhomogeneous polymeric fluids. The formalism permits an exact embedding of the relevant thermodynamic forces into the dynamical equations, regardless of the characteristic length scale…
We have studied details of the molecular dynamics in a series of pure polyalcohols by means of dielectric spectroscopy and H2 nuclear magnetic resonance (NMR). From glycerol to threitol, xylitol and sorbitol a systematic change in the dynamics of the primary and secondary relaxation is found. With increasing molecular…
The conduction mechanism in aluminum-doped zinc oxide has been studied. Structural investigation shows that crystallographic orientation as well as grain boundary scattering can be neglected. Based on the analysis of the Hall mobility, it has been found that scattering at neutral and ionized impurities dominates the m…
Superhigh strains of 15% for the Ni53Mn25Ga22 and 13.5% for the Ni54Mn23Ga23 with the nonmodulated martensite structure were achieved by variant reorientation. A strong magnetic anisotropy exists in the prefabricated single variant with the easy axis along the contraction [001] direction of the high-temperature cubic…
Electrically switchable photonic crystals are simply and rapidly formed by holographic polymerization-induced phase separation of liquid crystal from a monomer-liquid crystal mixture. We report the fabrication and electro-optical properties of liquid-crystal-filled polymer photonic crystals of orthorhombic F symmetry.…
We have prepared single-crystalline films of BaFeO3, which may contain high valent Fe4+ ions, on (100) SrTiO3 substrates by pulsed laser-beam deposition. The reflection high-energy electron diffraction patterns for the films apparently show a C4 symmetry operation, suggesting that the sample had a pseudocubic perovski…
Heusler alloys Co2MnX, where X is Ge or Si, are predicted by the band theory to be a half-metallic ferromagnets, i.e., metals with all conduction electrons of the same spin state. To date, Heusler alloys have been measured with spin polarizations of 50%–60%, higher than Fe (∼40%), but not a true half metal. Structural…