Materials Literature
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The resistivity, ρ, of ceramic La 1−x Ca x Mn 1−y Fe y O 3 with x = 0.3 and y = 0.0–0.09 is found to obey, between a temperature T v ≈ 310–330 K and the ferromagnetic-to-paramagnetic transition temperature, T C = 259–119 K (decreasing with y ), the Shklovskii–Efros-type variable-range hopping conductivity law, ρ( T )…
The fabrication of high quality, robust, and photoactive ITO electrodes is reported. Electrostatic and van der Waals interactions have been used for the step-by-step deposition of layers containing a fullerene−porphyrin dyad as the active layer. The new electrodes give rise to improved light harvesting features in the…
We show that, contrary to the prevailing perception, dislocations can become more mobile by zipping together to form junctions. In a series of direct atomistic simulations, the critical stress to move a junction network in a [110] plane of bcc molybdenum is found to be always smaller ( approximately 50%) than that req…
The structure and oxidation state of emeraldine base polyaniline (PANI) in N -methylpyrrolidinone solutions that have been heated to 120−190 °C have been characterized by solid-state NMR, UV/vis, FTIR, and GPC. The spectroscopic studies reveal that the polymer is completely converted to its fully reduced leucoemeraldi…
Nanostructuring silicon is an effective way to turn silicon into a photonic material. In fact, low-dimensional silicon shows light amplification characteristics, non-linear optical effects, photon confinement in both one and two dimensions, photon trapping with evidence of light localization, and gas-sensing propertie…
Inert gas condensation (IGC) has been employed to produce nanoparticles of the low-temperature combustion catalyst CuO x /CeO 2 . For the first time we have used a multiple heating crucible setup to tailor various morphologies over the whole compositional range (2−98% Cu). The factors that control the growth, structur…
A binary oxide, polycrystalline V 2 O 5, has been demonstrated to exhibit visible-light photochromism virtually for the first time. The oxide turns blue-black upon irradiation with visible laser light (514.5 nm) in air due to photoreduction of V 5+, and this effect is confirmed to be irradiation-induced, not heat-indu…
In this paper we present second harmonic generation (SHG) experiments designed to confirm the mechanism and quantify the transformation kinetics of the β–δ solid state phase transition in the organic nitramine molecule octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The β phase adopts a centrosymmetric crystal…
We report on investigations of type I clathrate Si and Ge compounds with Ba partially substituted by rare earth atoms. Novel compounds from framework-deficient solid solutions Ba 8 Al x Si 42−3/4 x □ 4−1/4 x and Ba 8 Ga x Si 42−3/4 x □ 4−1/4 x ( x = 8, 12, 16; □, open square... lattice defect) have been prepared and c…
The coordinately unsaturated terbium complexes Tb.1 and Tb.2 possess two labile metal-bound water molecules that can be displaced upon metal chelation to aromatic carboxylic anions such as salicylic acid in water, which gives rise to large enhancements in the Tb(III) luminescence.
We have measured both the static and dynamic structure factors of a single dendrimer with small-angle x-ray scattering (SAXS) and neutron spin-echo spectroscopy under good solvent conditions with the aim of finding a consistent correlation between the structural properties of dendrimers and their dynamic behavior. The…
The structural changes of bovine serum albumin (BSA) and hen egg white lysozyme (HEL) upon their adsorption onto the surface or their embedding into the interior of poly(allylamine hydrochloride)-(poly(styrenesulfonate) (PAH-PSS) multilayer architectures were investigated by attenuated total reflection Fourier transfo…
An investigation of possibilities for superconductivity mediated by spin fluctuations in some elementary metals is motivated by the recent discovery of superconductivity in the hcp high-pressure phase of iron. The electronic structure, the electron-phonon coupling ($λ_{ph}$) and the coupling due to spin-fluctuations (…
Azobenzenes substituted with two urea groups, and especially the 2,2‘-disubstituted azobenzenes, form thermoreversible gels with a wide range of organic solvents at concentrations which are in some cases even as low as 0.2 mM. Most remarkably, the 2,2‘-disubstituted azobenzene gelator can form two different morphs, wh…
We study a scheme for electrical detection of the spin resonance (ESR) of a single electron trapped near a Field Effect Transistor (FET) conduction channel. In this scheme, the resonant Rabi oscillations of the trapped electron spin cause a modification of the average occupancy of a shallow trap, which can be detected…
CO adsorption on small cationic, neutral, and anionic Aun (n=1–6) clusters has been investigated using density functional theory in the generalized gradient approximation. Among various possible CO adsorption sites, the on-top (one-fold coordinated) is found to be the most favorable one, irrespective of the charge sta…
Structural genomics is emerging as a principal approach to define protein structure-function relationships. To apply this approach on a genomic scale, novel methods and technologies must be developed to determine large numbers of structures. We describe the design and implementation of a high-throughput structural gen…
Abstract The availability of efficient low‐cost ultraviolet (UV) film polarizers is of vital importance to a number of applications, which rely on the use of polarized light in the near‐UV regime. We describe here the preparation of such elements based on stretch‐oriented films comprising poly(vinyl alcohol) and a com…
The interaction of oxygen with titanium deposited on polycrystalline aluminum surfaces has been studied at room temperature and low oxygen pressures, using AES, XPS, and ARXPS. The growth of titanium on the aluminum surfaces occurs in two stages: formation of a uniform TiAl x layer up to ∼4 monolayers (ML), followed b…
Block copolymer nanofibers (BCNs) may be viewed as the macroscopic counterparts of polymer chains. While many techniques exit for the fractionation and characterization of polymer chains, these techniques generally fail when applied to BCNs. Reported in this paper is our preliminary success in fractionating polystyren…