Materials Literature
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An investigation was carried out of the molecular interactions and local relaxation dynamics in glassy polymer networks exposed to moisture. Stoichiometric and off-stoichiometric mixtures of the diglycidyl ether of bisphenol A (DGEBA) and diethylene triamine (DETA) were prepared, cured, and investigated. The physical…
The interactions between high molecular weight chitosans (fraction of acetylated units (F(A)) = 0.10 or 0.50) and lignosulfonates of varying molecular weights (5000-400000 g/mol) and degrees of sulfonation (0.39-0.64) were studied. Lignosulfonates and chitosans form primarily insoluble polyelectrolyte complexes when m…
The nature and origin of ferromagnetism in magnetic semiconductors is investigated by means of highly precise electronic and magnetic property calculations on MnxGe1-x as a function of the location of Mn sites in a large supercell. Surprisingly, the coupling is not always ferromagnetic (FM), even for large Mn-Mn dista…
The conductance of a molecular junction is commonly determined by either charge-transfer-doping, where alignment of the Fermi energy to the molecular levels is achieved, or tunnelling through the tails of molecular resonances within the highest-occupied and lowest-unoccupied molecular-orbital gap. Here, we present an…
A lightweight nickel hydroxide electrode was obtained through developing a stable α-phase nickel hydroxide with a 10 at. % Al substitution. The effects of an Al addition within 10−30 at. % on the interslab distance of the (001) plane as well as on the electrochemical properties were investigated. Pasted α- and β-type…
Using a first principles based, magnetic tight-binding total energy model, the magnetization energy and moments are computed for various ordered spin configurations in the high pressure polymorphs of iron (fcc, or $γ$-Fe, and hcp, or $ε$-Fe), as well ferromagnetic bcc iron ($α$-Fe). For hcp, a non-collinear, antiferro…
We report a study in which Andreev reflection using a Nb point contact is used to measure the transport spin polarization of the $4d$ itinerant ferromagnet ${\mathrm{SrRuO}}_{3}$ in the ballistic limit of transport. The degree of transport spin polarization is comparable to that of the hole-doped rare-earth manganites…
We derive underdamped evolution equations for the order-parameter (OP) strains of a proper ferroelastic material undergoing a structural transition, using Lagrangian variations with Rayleigh dissipation, and a free energy as a polynomial expansion in the ${N=n+N}_{\mathrm{op}}$ symmetry-adapted strains. The ${N}_{\mat…
We report on the isothermal crystallization behavior of thin (film thickness d < 500 nm) and ultrathin ( d < 100 nm) films of poly(ethylene oxide) (PEO), as well as pyrene end-labeled PEO, on native silicon studied by in situ hot stage atomic force microscopy (AFM). Individual lamellae were imaged during crystallizati…
The phase behavior of poly-N-isopropylacrylamide (PNIPAM) nanoparticles dispersed in water is investigated using a thermodynamic perturbation theory combined with light-scattering and spectrometer measurements. It is shown how the volume transition of PNIPAM particles affects the interaction potential and determines a…
An EDTA bonded conducting polymer modified electrode (EDTA-CPME) was fabricated by polymerization of 3',4'-diamino-2,2';5',2''-terthiophene monomer on a GCE, followed by the reaction with EDTA in the presence of catalyst. The surface of the resulting modified electrode was characterized with EQCM, ESCA, SEM, Auger ele…
We have identified a strategy to communicate a chemical signal between two independent molecular components. One of them is a photoactive merocyanine that switches to a spiropyran, releasing a proton, when stimulated with visible light. The other is a 4,4'-pyridylpyridinium monocation that captures the released proton…
Four years after the first structure determination by powder diffractometry (SDPD) round robin, a second one shows that SDPD is still not routine.
We use the shear transformation zone (STZ) theory of dynamic plasticity to study the necking instability in a two-dimensional strip of amorphous solid. Our Eulerian description of large-scale deformation allows us to follow the instability far into the nonlinear regime. We find a strong rate dependence; the higher the…
Magnesium oxide nanocrystals are shown to be selective catalysts for the benzylation of aromatics with benzyl chloride, in the order xylene > toluene >> benzene. Normal polycrystalline MgO is not as effective as the nanomaterials. However, at the highest surface area, normally most reactive MgO samples (aerogel prepar…
We have characterized the structure, molecular orientation, and crystallization kinetics of isothermally crystallized thin (film thickness d < 500 nm) and ultrathin films ( d < 100 nm) of poly(ethylene oxides) on oxidized silicon substrates by a combination of microscopic and spectroscopic methods. In situ hot stage a…
The effect of Cr 3+ concentration on the various hyperfine interactions for the ferrite system Li 0.5+t Cr x Sb t Fe 2.5-2t-x O 4 , 0.0 ≤ x ≤ 1.0, x in steps of 0.2 and t = 0.1, have been studied at room temperature using Mössbauer spectroscopy. The isomershift and the quadrupole splitting are almost negligibly influe…
Abstract Electrical resistivity measurements have been performed on Cu x As 40 Se 60– x glasses with x between 0 and 28 at% of Cu. The resistivity of these glasses continuously decreases and saturates at higher quasi‐hydrostatic pressures. The pressure derivative of the electrical resistivity shows distinct changes as…
The photoionization spectra of isolated chromium clusters from ${\mathrm{Cr}}_{4}$ to ${\mathrm{Cr}}_{25}$ have been recorded. The vertical ionization energies ${(E}_{i}^{v})$ derived from the spectra decrease discontinuously with increasing cluster size. The ${E}_{i}^{v}$ values determined for ${\mathrm{Cr}}_{n}$ spe…
The Landau-de Gennes model for nematic liquid crystal bulk and interfaces has been extended to nematic triple lines involving the intersection of two isotropic fluids and one nematic liquid crystalline phase. A complete set of bulk, interface, and triple line force and torque balance equations has been formulated. The…