Materials Literature
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The effects of substrates and solvent on polymer formation, number-average molecular weight (M(n)), polydispersity, and end-group structure for lipase-catalyzed polycondensations were investigated. Diphenyl ether was found to be the preferred solvent for the polyesterification of adipic acid and 1,8-octanediol giving…
We report anisotropic resistivity measurements on a ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ single crystal over a temperature T range from 2 to 400 K and in magnetic-fields H up to 14 T. For $T>~218\mathrm{K},$ the temperature dependence of the zero-field in-plane resistivity ${\en…
The dynamical mean-field method is used to analyze the magnetic transition temperature and optical conductivity of a model for the ferrimagnetic double perovskites such as ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}.$ The calculated transition temperatures and optical conductivities are found to depend sensitively on the b…
A type of a composite material is proposed, the microwave permittivity of which changes under the effect of a dc magnetic field applied to the whole composite sample. The composite consists of short ferromagnetic wires embedded into a dielectric matrix. A strong field dependence of the permittivity is seen in the vici…
High-temperature (high-$T)$ and high-electric-field (high-$E)$ effects on $\mathrm{Pb}[({\mathrm{Zn}}_{1/3}{\mathrm{Nb}}_{2/3}{)}_{0.92}{\mathrm{Ti}}_{0.08}]{\mathrm{O}}_{3}$ were studied comprehensively by neutron diffraction in the ranges $300<~T<~550\mathrm{K}$ and $0<~E<~15\mathrm{k}\mathrm{V}/\mathrm{…
Binary colloidal suspensions are assembled into planar superlattices using ac electric fields. Either triangular or square-packed arrays form, depending on the frequency and relative particle concentrations. The frequency dependence is striking since superlattices develop at low and high frequencies but not at interme…
The role of electron acceptors in semiconductor photocatalysis is critical in determining the overall photoefficiencies, kinetics, and mechanisms. Polyoxometalates (POMs) are efficient electron acceptors and carriers in TiO 2 photocatalysis. The electron transfer mediating behaviors of a POM (PW 12 O 40 3- /PW 12 O 40…
We report on the growth, structural as well as magnetic characterization of (Ga,Mn)N epitaxial layers grown directly on 4H–SiC(0001) by reactive molecular-beam epitaxy. We focus on two layers grown under identical conditions except for the Mn/Ga flux ratio. Structural characterization reveals that the sample with the…
Wave front pinning and propagation in damped chains of coupled oscillators are studied. There are two important thresholds for an applied constant stress $F$: for $|F| F_{cs}$ (static Peierls stress) there are only stable moving wave fronts. For piecewise linear models, extending an exact method of Atkinson and Cabrer…
We present a density functional study of reduced and stoichiometric rutile TiO2 (110) surfaces, and of binding of gold monomers and dimers to them. On the stoichiometric TiO2 surface, a Au atom binds to either a five-coordinated Ti atom on the basal plane, or atop a bridging oxygen atom. The two sites have nearly the…
This 2003 book covers the fundamentals of conventional transmission electron microscopy (CTEM) as applied to crystalline solids. Emphasis is on the experimental and computational methods used to quantify and analyze CTEM observations. A supplementary website containing interactive modules and free Fortran source code…
Oil-in-water emulsions containing cationic droplets stabilized by lecithin-chitosan membranes were produced using a two-stage process. A primary emulsion was prepared by homogenizing 5 wt % corn oil with 95 wt % aqueous solution (1 wt % lecithin, 100 mM acetic acid, pH 3.0) using a high-pressure valve homogenizer. Thi…
ZnO nanowires have been synthesized using a catalyst-assisted heteroepitaxial carbothermal reduction approach on a m-sapphire substrate. Intricate and uniform arrays have been obtained with each nanowire forming an angle ∼30° with the substrate normal. Photoluminescence studies at room temperature for wavelengths betw…
Photoresponse characteristics of polycrystalline ZnO films prepared by the unbalanced magnetron sputtering technique have been analyzed for ultraviolet photodetector applications. Changes in the crystallographic orientation and the microstructure of the films due to in situ bombardment effects during film growth have…
The mechanism of nanoclay exfoliation was investigated in epoxy−clay nanocomposites system. The elastic force exerted by cross-linked epoxy molecules inside the clay galleries was found responsible for exfoliation of clay layers from the intercalated tactoids. Complete exfoliation of clay galleries was observed under…
Elaborate one-dimensional photonic crystals are constructed from a variety of organic and biopolymers, which can be dissolved or melted, by templating the solution-cast or injection-molded materials in porous silicon or porous silicon dioxide multilayer (rugate dielectric mirror) structures. After the removal of the t…
AFe 1/2 B 1/2 O 3 (A=Ba , Sr, Ca; B=Nb, Ta, Sb) ceramics were synthesized and temperature dependences of dielectric permittivity were measured at different frequencies. The experimental data obtained show very high values of dielectric permittivity in a wide temperature interval that is inherent to so-called high-k ma…
We report on the transport properties of random networks of single-wall carbon nanotubes fabricated into thin-film transistors. At low nanotube densities (∼1 μm−2) the networks are electrically continuous and behave like a p-type semiconductor with a field-effect mobility of ∼10 cm2/V s and a transistor on-to-off rati…
In the present study, we report the systematic investigation of the effect of chemical oxidation on the structure of single-walled carbon nanotubes (SWNTs) by using different oxidants. The oxidation procedure was characterized by using infrared spectroscopy and transmission electron microscopy (TEM). The SWNTs were pr…
A new asymmetric derivative of 1,4,7-triazacyclononane with two iminocarboxylic pendant arms attached to the macrocyclic ring has been designed and prepared. Lanthanide complexes of L1 and of its previously reported symmetric analogue L, containing three pendant arms, are described. The complexes [Ln(L)] (Ln = Gd, Eu,…