Materials Literature
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Carbon nanocages, with remarkably large mesoporous volumes, have been synthesized by the deposition of p -xylene over a Co/Mo catalyst in supercritical carbon dioxide. Nanocages with diameters ranging between 10 and 60 nm were synthesized at temperatures between 650 and 750 °C. The surface area and pore volume of the…
We have designed and fabricated an efficient grating coupler for coupling light between optical fibers and silicon-on-insulator waveguides. The coupler consists of 88-nm-wide slits, etched at an angle of 58deg to the surface normal. They are defined by direct etching with a focused ion beam, using iodine gas and an al…
Using a synchrotron x-ray radiation source and a diamond anvil cell we measured the functional dependences of the lattice parameters of (Ti(0.5),V(0.5))(2)AlC and (Ti(0.5),Nb(0.5))(2)AlC to quasi-hydrostatic pressure of the order of 50 GPa. Like for other solids in this family of layered ternary carbides and nitrides,…
Abstract Blends of two biodegradable and semicrystalline polymers, poly( L ‐lactic acid) (PLLA) and poly(butylene succinate‐ co ‐adipate) (PBSA), were prepared by solvent casting in different compositions. The miscibility, morphology, and thermal behavior of the blends were investigated using differential scanning cal…
We report here the observation of significant room-temperature ferromagnetism in a semiconductor doped with nonmagnetic impurities, Cu-doped rutile TiO 2 thin films grown by reactive magnetron sputtering. Films annealed in air were nonmagnetic while those annealed in vacuum were ferromagnetic with a Curie temperature…
The configuration and energetics of the mono-vacancy and self-interstitial of hcp zirconium, both in the ground state and the saddle-point configurations, are computed atomistically using the conjugate gradient method, from which the diffusion anisotropy difference (DAD) between the two types of defects is obtained. B…
We have measured the lattice constants and Debye–Waller factors of ZrC from 12 to 1600 K using neutron diffraction. The data have been analyzed with the Grüneisen equation of state using an existing procedure for the Debye–Waller factors and a new procedure for the CTE that takes the temperature dependence of the elas…
Nickel zinc ferrite (Ni-ZnFe2O4)-filled natural rubber (NR) composite was prepared at various loading of ferrite. The tensile properties included in this study were tensile strength, tensile modulus and elongation at break. The tensile strength and elongation at break of the composites increased up to 40 parts per hun…
The relaxation of the electronic spin S of a paramagnetic metal ion with fully quenched orbital angular momentum in its ground state is investigated in an external magnetic field through a systematic study of the time correlation functions governing the evolution of the statistical operator (density matrix). Let omega…
The mechanical behavior of single-walled carbon nanocones (SWCNCs) with 19.2\ifmmode^\circ\else\textdegree\fi{} apex angles under compression was investigated in the study reported herein. The analysis was performed using molecular dynamics simulation. Two different loading directions, i.e., axial compression and in-p…
Results on the effects of a metal catalyst and the role of CO as a reducing agent are reported for a resin char and a Wyodak coal char, as well as demineralized samples of the latter. The effect of an active metal catalyst, such as potassium in the current work, is to significantly increase the reactivity both by incr…
We present a systematic investigation of dislocation motion, dislocation interactions, and the collective behaviour of dislocations in high strain-rate deformation. Based on results from three-dimensional dislocation dynamics simulations, we find that employing the accurate, full-dynamics, equation of motion (i.e. tha…
Uniformly degrading biomaterials with adjustable degradation product migration rates were customized by combining the advantages of cross-linked poly(epsilon-caprolactone) with the hydrophilic character of poly(1,5-dioxepan-2-one). Hydrolytic degradation of these random cross-linked networks using 2,2'-bis-(epsilon-ca…
We have studied the photoluminescence (PL) characteristics of nanometer-sized amorphous silica particles after appropriate annealing in air and in vacuum. A broad visible PL band peaking at ∼450 nm, which is characterized by a nonexponential decay in the order of nanoseconds, has been found to develop when the samples…
In this paper, we demonstrated a unique and simple method for fabricating colloidal particles of complex structures using oil-in-water emulsion droplets as confined geometries. A variety of structural motifs were produced using binary colloids of microspheres of polystyrene (PS) or silica and nanosized particles as th…
The state of nickel ions in two BEA zeolites was studied by X-ray diffraction (XRD), temperature-programmed reduction (TPR), and Fourier transform infrared (FTIR) spectroscopy using CO and NO as probe molecules. One of the samples, NiAlBEA (0.9 wt % of Ni), was prepared by conventional ion exchange, and the other, NiS…
We study the magnetoelectric coupling in $\mathrm{Y}\mathrm{Mn}{\mathrm{O}}_{3}$ single crystal, in which a part of ${\mathrm{Mn}}^{3+}$ ions is substituted by nonmagnetic ${\mathrm{Ga}}^{3+}$ ions. While the antiferromagnetic ordering temperature is gradually suppressed by Ga doping, the magnetocapacitance is enhance…
Density functional (DFT) calculations have been used to investigate the stability of point defects in uranium dioxide. Correlation effects are taken into account within the DFT + U approach as implemented in the Vienna ab initio simulation package (VASP). More particularly, the formation energies of both intrinsic and…
The physical and optical properties of quantum dots (QDs) are governed by their particle size and shape. In this study, near-infrared-emitting PbSe QDs were synthesized with controlled size (between 7 and 12 nm) and shape (spheres, octahedrons/cubes), with tunable emission from 1200 to 1500 nm. The hydrophobic PbSe QD…
A general synthetic method has been developed to precisely control the shape and size of ZnS nanorods, nanowires, whiskers, and hierarchical nanostructures. The control was achieved owing to creation of specific growth conditions while adopting carefully selected catalysts and tuning their size during a catalytic vapo…