Materials Literature
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Optical reflectors in animals are diverse and ancient. The first image-forming eye appeared around 543 million years ago. This introduced vision as a selection pressure in the evolution of animals, and consequently the evolution of adapted optical devices. The earliest known optical reflectors--diffraction gratings--a…
Photo-switching between a charge-ordered insulating (CO) state and a metallic (M) state has been successfully realized in an organic conductor α-(BEDT-TTF) 2 I 3 at low temperatures. The large photocurrent induced by the pulsed laser excitation with a photon energy of 2.6 eV had two components. The fast-decaying compo…
Raman spectroscopy and confocal Raman imaging with 514 nm excitation was performed on recently developed ultralong carbon nanotubes grown by the "fast-heating" chemical vapor deposition (CVD) method. The ultralong nanotubes are found to consist of both semiconducting and metallic types, with spectra that are consisten…
To fabricate a "mechano-active" tubular scaffold of nonwoven mesh-type small-diameter artificial graft made of the synthetic durable elastomer, segmented polyurethane, the fabrication technique of electrospinning on a mandrel under a high rotation speed and transverse movement was used. Emphasis was placed on how the…
Abstract Nickel formate was used as a catalyst to improve the flame‐retardancy of intumescent systems based on ammonium polyphosphate (APP) and pentaerythritol (petol) in polypropylene (PP). Limited oxygen index (LOI), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to characterize the fire‐reta…
The investigations of complete nitrogen atom transfer reactions from (nitrido)manganese(V) salen to manganese(III) complexes of porphyrins and corroles revealed that stabilization of the [Mn(N)]2+ moiety is in the order of corrole > porphyrin > salen. The first kinetic examination of this quite fundamental reaction ex…
We propose switchable two-dimensional (2D) diffractive gratings with periodic refractive-index modulation arising from layer undulations in cholesteric liquid crystals. The cholesteric cell can be switched between two states: (1) flat layers of a planar cholesteric texture and (2) a square lattice of periodic director…
Recent experiments showed significant adsorption of bovine serum albumin (BSA) in spherical polyelectrolyte brushes (SPB) consisting of polyacrylic acid, even for pH values above the isoelectric point of the protein, when both protein and polyion are negatively charged. To describe these experimental findings theoreti…
The pyroelectric properties of [111]-oriented Pb(Mg1∕3Nb2∕3)O3–0.29PbTiO3 (PMN-0.29PT) crystals have been investigated both as a function of frequency and temperature. At room temperature, [111]-oriented crystals have a high pyroelectric coefficient of 12.8×10−4C∕m2K and a low thermal diffusivity of ∼3.7×10−7m2∕s. The…
Metallized-film capacitors have the property, even under high continuous voltage, to self-heal i.e., to clear a defect in the dielectric. The self-healing process is a consequence of a transient arc discharge. It has been previously shown that during the discharge, due to Joule effect, the metal is vaporized until the…
We present a rectifying manganite–titanate heterojunction exhibiting a magnetic field tunable depletion layer. This creates a large positive magnetocapacitance, a direct measure of the field-induced reduction of the effective depletion width across the junction. Furthermore, the reduction of the junction barrier shift…
The effect of water-soluble, nonionic polymers on the crystallization of calcium carbonate is reported. The polymers used were poly(vinyl alcohol) (PVA), polyacrylamide, poly( N -isopropyl acrylamide), poly( N -vinyl pyrrolidone), and poly(ethylene oxide). In addition, several smaller molecules containing hydroxyl gro…
Abstract A series of novel biodegradable unsaturated poly(ester amide)s (UPEAs) were synthesized through the solution polycondensation of two unsaturated monomers, di‐ p ‐nitrophenyl fumarate and L ‐phenylalanine 2‐butene‐1,4‐diol diester p ‐toluene sulfonate, and four other saturated monomers in different combination…
High-quality c-axis-oriented Ca3Co4O9 thin films have been grown directly on Si (100) wafers by pulsed-laser deposition without prechemical treatment of the substrate surface. Cross-sectional transmission electron microscopy shows good crystallinity of the Ca3Co4O9 films. The Seebeck coefficient and resistivity of the…
Second order nonlinear optical properties of a series of trinitrosubphthalocyanine (SubPc) isomers were studied experimentally by electric field induced second harmonic (EFISH) generation and hyper Rayleigh scattering (HRS). These experimental values were compared to the ones obtained theoretically employing both sum…
Abstract High‐quality freestanding polyindole (PIn) films were synthesized electrochemically through the direct oxidation of indole in pure boron trifluoride diethyl etherate (BFEE). The oxidation potential of indole in this medium was measured to be only 0.86 V versus a saturated calomel electrode, which was lower th…
Fabrication and characterization of a nanoelectromechanical switching device consisting of a suspended multiwalled carbon nanotube and self-aligned electrodes is reported. The device has a triode structure and is designed so that a suspended carbon nanotube is mechanically switched to one of two self-aligned electrode…
Strong photoluminescent emission has been measured at room temperature for noncrystalline $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_{3}$ (BT) perovskite powders. A joint experimental and theoretical study has been carried out to rationalize this phenomenon. From the experimental side, BT powder samples have been synthesized…
Abstract Nitric acid treated multiwalled carbon nanotubes (A‐CNTs) were dispersed in a waterborne polyurethane (WBPU) matrix to obtain WBPU/A‐CNT nanocomposite films (99.99/0.01–98.5/1.5) with enhanced thermal, mechanical, and electrical properties. By X‐ray photoelectron spectroscopy (XPS), the oxygen content of the…
Fe- and Cu-codoped ZnO was previously reported as a room-temperature dilute magnetic semiconductor. We have investigated the origin of the ferromagnetism in Zn0.95−xFe0.05CuxO using the zero-field Fe57 nuclear magnetic resonance and neutron diffraction. These measurements reveal that some Fe ions of Zn0.95−xFe0.05CuxO…