Materials Literature
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According to the spin-torque model, current-driven magnetic dynamics in ferromagnetic multilayers is determined by the transfer of electron spin perpendicular to the layers' magnetizations. By separating the largest contributions to the magnetic dynamics, we demonstrate that the dominant effect of spin-torque is rathe…
Arbitrary waves incident on a solid embedded nanoparticle are studied. The acoustic vibrational frequencies are shown to correspond to the poles of the scattering cross section in the complex frequency plane. The location of the poles is unchanged even if the incident wave is nonplanar. A second approach approximating…
The size effects on the optical properties of vanadium dioxide nanoparticles in ordered arrays have been studied. Contrary to previous VO2 studies, we observe that the optical contrast between the semiconducting and metallic phases is dramatically enhanced in the visible region, presenting size-dependent optical reson…
The best of both worlds: The synthesis of carbon-encapsulated iron-based magnetic nanoparticles is described (see picture: left TEM image, right model). With such small catalysts that have macroscopic magnetic properties, the advantages of homogeneous or colloidal and heterogeneous catalysts can be combined.
Uniform nanofibers composed of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] and its blends with poly(3-hexylthiophene) are formed by co-electrospinning their solutions with poly(vinyl pyrrolidone) (PVP) through a coaxial capillary system, followed by extraction of the PVP phase (see Figure). Compared with…
A polymer-stabilized liquid-crystal blue phase with a Kerr constant 170 times larger than that of nitrobenzene is shown to be capable of microsecond electro-optical switching over a wide temperature range in flat Kerr cells, without need for additional surface processing to generate alignment. The Figure shows a polar…
Finding the right angle: The contact angle of nanoparticles at the water/oil interface can be engineered close to 90° by capping with ligands containing carboxylic ester terminal groups. This drives the nanoparticles to self-assemble into close-packed films (see picture), and thus provides the opportunity to create tw…
We report on NMR evidence about a novel effect in La 1 − x Ca x MnO 3 + δ systems with cation deficience. We show that in the low–Ca-doping regime, these systems exhibit a very strong hyperfine field at certain La nuclear sites, which is not present in the stoichiometric compounds. Comparison of our NMR results with r…
In an effort to further understand the effects of molecular size and shape of macromolecular diffusants on the diffusion in hydrophilic polymer solutions and gels, hyperbranched polyglycidols have been synthesized as hydrophilic diffusants and characterized. Four of these hyperbranched polymers were selected for the s…
Polymer dynamics in a cross-linked poly(ethylene oxide−propylene oxide) random copolymer, both neat and doped with an inorganic salt, is investigated by means of quasi-elastic neutron scattering (QENS) as a function of temperature and momentum transfer. Data from a high-resolution backscattering instrument are reporte…
An electronically-controlled metamaterial-based transmission line (TL) is demonstrated for the first time and applied to a continuous-scanning leaky-wave (LW) antenna. This transmission line is a composite right/left-handed (CRLH) microstrip structure incorporating varactor diodes for fixed-frequency voltage-controlle…
Zinc sulphide (ZnS) thin films have been prepared on Pyrex substrates by the spray pyrolysis technique using zinc chloride and thiourea as precursors. The depositions were carried out on substrates heated at 450 °C. The films were then annealed under sulphur atmosphere for one hour at 450 or 500 °C. This process allow…
Monolayer catalysts containing binary active phases (VOx-CrOx, VOx-MoOx) were prepared by simultaneous deposition of the corresponding transition metal-oxo species on the TiO2 (anatase) surface using the equilibrium deposition filtration technique. The prepared samples contained various amounts of each transition meta…
We present a simple analytical mean-field theory for the pair interaction between two colloidal particles, based upon a recent mean-field equation for the depletion thickness δ which depends on the chain length N, the bulk concentration φ b, and the solvency χ. Only in the extremely dilute case is (in mean field) the…
The effect of composition on the true mechanooptical properties of thermoplastic poly(urethane urea)s was investigated by selectively varying the type and content of soft and hard segments. Real-time stress−strain−birefringence data together with off-line wide-angle X-ray scattering measurements revealed that soft seg…
A new series of stilbene-based chromophores have been used to prepare structurally related siloxane-based monolayers in order to determine which factors control the intermolecular chromophore−chromophore interactions in the solid state. The reaction of chromophore precursors 4-styrylpyridine ( 1 ), 4-[2-(4-bromophenyl…
Using a combined rational-combinatorial approach, stable copper binding sites were implemented in template-assembled synthetic four-helix bundle proteins constructed by three different helices with only 16 amino acid residues. These peptides include two histidines and one cysteine at positions appropriate for coordina…
Abstract The protective clothing and equipment required for certain sports may inhibit heat loss from the body and contribute to potentially harmful heat stress injuries. This study measured the thermal resistance (insulation) and evaporative resistance of a variety of sports ensembles worn for football, basketball, b…
Zeolite (silicalite-1) micromembranes having only approximately 0.005 mm2 of permeation area have been prepared on laser-perforated, 75-μm-thick stainless steel sheets. Arrays of these micromembranes performed well in the gas-phase separation of a propane/N2 mixture, showing a hydrocarbon permeance at least an order o…
The (2 )⟨111⟩ twinning energy landscape of BCC Mo is determined using the density functional theory for embryos containing 2 to 7 layers. The 2-layer embryo is metastable, whereas the 3- and 4-layer ones are unstable. Layer-by-layer growth starts at 5 layers. The twin boundary formation and migration energies are foun…