Materials Literature
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Photoluminescence and photoluminescence excitation (PLE) spectroscopy have been carried out on the ∼1550 nm I413/2→I415/2Er3+ emission from thin films of Er-doped As40Ge10Se25S25 glass deposited on silicon substrates by radio frequency sputtering. The PLE spectroscopy shows that the Er3+ emission is excited in the 1-μ…
Polarized Raman scattering by phonons is used to characterize thin films prepared by laser ablation of La1−xCaxMnO3 targets. It was found that, in the temperature range from 6 to 300 K, phonon spectra of La0.7Ca0.3MnO3 films exhibit observable differences from those in bulk materials (microcrystalline ceramics and sin…
We report the observation of a giant magnetoresistance effect in a low-temperature (LT-)GaAs/MnAs nanoscale ferromagnet hybrid structure. The MnAs nanomagnets are formed by ion implantation of Mn into LT GaAs and subsequent annealing. We have studied the magnetotransport using a vertically biased p+-GaAs/LT-GaAs:MnAs/…
The aging behavior of the ac susceptibility of randomly substituted ${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{TaO}}_{3}$ crystals reveals marked differences with spin glasses in that cooling rate effects are very important. The response to temperature steps (including temperature cycles) was carefully…
Single bubble sonoluminescence stability in ambient radius ( ${R}_{0}$), drive pressure ( ${P}_{a}$) phase space is examined for water partially saturated with pure argon, pure nitrogen, and argon/nitrogen mixtures in order to examine the dissociation hypothesis (DH) of Lohse and Hilgenfeldt [J. Chem. Phys. 107, 6986…
A very large optical absorption increase induced by continuous-wave laser irradiation is reported for free-standing porous silicon films oxidized at 800–950 °C. A maximum reversible optical-density change of 2.5 is obtained with a pump laser intensity of ∼20 W/cm2. The induced absorption is found to be strongly decrea…
The electrical conductivity and the conductivity relaxation of the fluoride glasses in the system with LiF content ranging from 10 to 60 mol% have been investigated in the frequency range 10 Hz-2 MHz and in the temperature range from 300 K to just below the glass transition temperatures. The conductivity shows a minim…
<div class="htmlview paragraph">A material selection including a natural material is conducted using a Simplified Life Cycle Assessment (SLCA) according to SETAC within the framework of Ford's Design for Environment (DfE) process. The aim has been to check both, the environmental performance of a design option c…
Abstract
We report the first experimental evidence of the cyclic form of ozone, found in three air stable surface reconstructions of MgO (111) annealed above 1450 \ifmmode^\circ\else\textdegree\fi{}C. The $\mathrm{MgO}(111)\ensuremath{-}(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}$…
We study the liquid anomalies arising from the Stell-Hemmer interaction, using molecular dynamics simulations and approximate 2D solutions. We observe in the liquid phase three types of anomalies: (i) An increase in specific volume upon cooling, (ii) an increase in isothermal compressibility upon cooling, and (iii) an…
The evolution of three-dimensional strain states and crystallographic domain structures of epitaxial colossal magnetoresistive La0.8Ca0.2MnO3 films have been studied as a function of film thickness and lattice mismatch with two types of (001) substrates, SrTiO3 and LaAlO3. In-plane and out-of-plane lattice parameters…
We use a Monte Carlo bond-switching method to study systematically the thermodynamic properties of a ``continuous random network'' model, the canonical model for such amorphous systems as $a$-Si and $a\ensuremath{-}{\mathrm{SiO}}_{2}$. Simulations show first-order ``melting'' into an amorphous state, and clear evidenc…
We use the dynamical mean field method to study the high-temperature resistivity of electrons strongly coupled to phonons. The results reproduce the qualtiative behavior of the temperature and disorder dependence of the resistivity of the 'A-15' materials, which is commonly described in terms of saturation, but imply…
The diffusivity of tagged particles is demonstrated to be heterogeneous on time scales comparable to or less than the stress relaxation time $\ensuremath{\cong}{\ensuremath{\tau}}_{\ensuremath{\alpha}}$ in a highly supercooled model liquid. The particle motions in the relatively active regions dominantly contribute to…
The achievement of high-quality continuous polycrystalline silicon (poly-Si) layers onto glass substrates by using aluminum-induced crystallization is reported. The crystallization behavior of dc sputtered amorphous silicon on glass induced by an Al interface layer has been investigated above and below the eutectic te…
Miscibility studies of poly(vinyl pyrrolidone)–polystyrene and poly(vinyl pyrrolidone)–poly(methyl methacrylate) in mixed common solvent (dimethyl formamide + cyclohexanone) have been carried out in different percentages of the blend components. The ultrasonic velocity, viscosity, density, and refractive index have be…
The present work compares the nucleation and crystallization process of poly(ethylene terephthalate) (PET) in bulk and when it is finely dispersed in a polycarbonate (PC) matrix. Two types of 80/20 PC/PET immiscible blends were prepared by twin-screw extrusion at different screw rotation rates in order to produce fine…
MQ silicone resins were synthesized through hydrolytic condensation of ethyl polysilicate and hexamethyldisiloxane. The structure of the MQ resins was characterized by NMR and GPC. The concentration of an acid catalyst was essential for the capping of functional groups with the monofunctional units. The acid-catalyzed…
A series of new polymethacrylate–silica chemical hybrid dental fillers has been prepared by the sol–gel reactions of poly[methyl methacrylate-co-3-(trimethoxysilyl) propyl methacrylate] or poly[3-(trimethoxysilyl)propyl methacrylate] with tetraethyl orthosilicate at various compositions. In these hybrid fillers, the p…