Materials Literature
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The electronic local density of states (LDOS) of single PbSe quantum dots (QDs) and QD molecules is explored using low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS). Both individual PbSe QDs and molecular aggregates of PbSe QDs (dimers, trimers, etc.) are mechanically stabilized in a two-dimen…
Abstract Molecular simulations are the most important tools to predict the properties of polymers and their blends. In this work, we have predicted the blend incompatibility of poly( n ‐vinyl pyrrolidone) (PVP) and poly(bisphenol‐A‐ether sulfone) (PES). Atomistic simulations were performed to compute the Flory‐Higgins…
In this study, the surface chemical properties of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) grown by catalytic decomposition of methane on nickel and cobalt based catalysts were studied by DRIFT (Diffuse Reflectance Infrared Fourier Transform) and transmission Infrared (IR) spectroscopy. The results show th…
We investigated the atomistic and electronic structure of the 90\ifmmode^\circ\else\textdegree\fi{} domain wall in $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ and the fundamental mechanism of domain switching induced by shear stress using first-principles density functional theory calculations within the local density ap…
Abstract The present investigation deals with the mechanical, thermal and viscoelastic properties of ternary composites based on low density polyethylene (LDPE)‐ethylene–propylene–diene terpolymer (EPDM) blend and high density polyethylene (HDPE)‐EPDM blend reinforced with short jute fibers. For all the untreated and…
The present work addresses a market demand for high refractive index ( n D ) coatings. We prepared organic UV-curable oligomers with n D > 1.6. We found a novel way to prepare sulfur-containing UV-curable high n D oligomers of melamine and urethane acrylates. Refractive indices of the synthesized oligomers were betwee…
Strategies to create thin films using layer-by-layer methods use oppositely charged polymeric polyelectrolytes for both or at least one component to beneficially exploit multitopic electrostatic interactions between the deposited layers with opposite charges. In contrast, the electrostatic deposition of tetracationic…
Folding under pressure: High-pressure crystallography of an Mn6 single-molecule magnet reveals dramatic changes in the intramolecular geometry of the magnetic core (see picture; Mn purple, O red, N blue). These structural changes effect the magnetic properties of the molecule: the magnitude of the ferromagnetic exchan…
We report on a series of experiments in which a Hele-Shaw cell containing aqueous solutions of NH 4 Cl was translated at prescribed rates through a steady temperature gradient. The salt formed the primary solid phase of a mushy layer as the solution solidified, with the salt-depleted residual fluid driving buoyancy-dr…
Cotton, jute, flax, ramie, hemp, sisal, manila hemp, wool, and silk are some of the major natural fibres, which are widely being used throughout the world. Apart from these, a large number of fibres grown in much smaller quantities in different parts of the world have local economic importance and are mostly consumed…
Conventional techniques to measure diffusion coefficients in liquid metals and alloys are hampered by buoyancy-driven convective fluid flow and chemical reactions of the liquids with container material. To overcome these obstacles we combined containerless processing via electromagnetic levitation with quasielastic ne…
The defect structure of hard copper-modified polycrystalline ${\mathrm{PbTiO}}_{3}$ ferroelectrics is investigated by means of electron paramagnetic resonance and hyperfine sublevel correlation spectroscopy, as well as density functional theory calculations. Special emphasis is put on the $^{207}\mathrm{Pb}$-hyperfine…
The potential for magnesia-based cements to improve the mechanical performance upon carbonation was recently identified. Key parameters were defined as drying, concentration and transport of CO 2 into the sample. However, the trials were performed on small-scale samples of cement paste only. Following this an investig…
Abstract Biodegradable thermoplastic‐based composites reinforced with kenaf fibers were prepared and characterized. Poly(lactic acid) (PLA) was selected as polymeric matrix. To improve PLA/fibers adhesion, low amount of a proper reactive coupling agent, obtained by grafting maleic anhydride onto PLA, was added during…
We discuss steady state crack growth in the spirit of a free boundary problem. It turns out that mode I and mode III situations are very different from each other: In particular, mode III exhibits a pronounced transition towards unstable crack growth at higher driving forces, and the behavior close to the Griffith poi…
The electronic structure is found to be understandable in terms of free-atom term values and universal interorbital coupling parameters, since self-consistent tight-binding calculations indicate that Coulomb shifts of the d-state energies are small. Special-point averages over the bands are seen to be equivalent to tr…
The attenuation of longitudinal acoustic phonons up to frequencies nearing 250 GHz is measured in vitreous silica with a picosecond optical technique. Taking advantage of interferences on the probe beam, difficulties encountered in early pioneering experiments are alleviated. Sound damping at 250 GHz and room temperat…
The role of exchange-correlation effects in non-equilibrium quantum transport through molecular junctions is assessed by analyzing the IV curve of a generic two-level model using self-consistent many-body perturbation theory (second Born and GW approximations) on the Keldysh contour. For weak molecule-lead coupling we…
The infrared phonon spectrum of the spinel CdCr2O4 is measured as a function temperature from 6 K to 300K. The triply degenerate Cr phonons soften in the paramagnetic phase as temperature is lowered below 100 K and then split into a singlet and doublet in the low T antiferromagnetic phase which is tetragonally distort…
We analyze recent experiments on the dilute rare-earth compound LiHo_xY_(1-x)F_4 in the context of an effective Ising dipolar model. Using a Monte Carlo method we calculate the low-temperature behavior of the specific heat and linear susceptibility, and compare our results to measurements. In our model the susceptibil…