Materials Literature
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In this Letter we describe measurements of the light emission evolution for single-bubble sonoluminescence. In particular, we show that the evolution of intensity for an air bubble depends on whether or not the bubble has previously been in a steady sonoluminescence state. Our results provide strong experimental evide…
The dielectric relaxation of Ba0.7Sr0.3TiO3 thin films was investigated up to K band (20 GHz) using time domain and frequency domain measurements. Our results show that from 1 mHz to 20 GHz, the dielectric relaxation of the complex capacitance of Ba0.7Sr0.3TiO3 thin films can be understood in terms of a power law depe…
We report x-ray diffraction measurements of the structure factor S ( Q ) and the radial distribution function g ( r ) of levitated liquid silicon in the stable and supercooled states. Supercooling results in a sharpening of the first peak in S ( Q ) and shift to an 8% higher Q value, the appearance of a double shoulde…
The $\mathrm{SiC}\left(111\right)\ensuremath{-}\left(3\ifmmode\times\else\texttimes\fi{}3\right)$ phase was analyzed by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED) holography, density functional theory (DFT), and conventional LEED. A single adatom per unit cell found in STM acts as a be…
Dynamic fracture experiments measure crack velocity versus energy flux to the tip. We report here the first calculation of this quantity in a realistic setting, using molecular dynamics to study silicon. The results require relating the short length and time scales of simulations to the long length and time scales of…
Measured distortions of the $\mathrm{Mn}\ensuremath{-}\mathrm{O}$ bond length distribution from x-ray-absorption fine-structure measurements are found to relate linearly to the doped hole concentration $x$ at room temperature in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$. Comparison of the d…
Experiments on ferromagnetic thin films have measured the dependence of the hysteresis loop area on the amplitude and frequency of the external field, $A$=$A(H_{0},ω)$, and approximate agreement with numerical simulations of Ising models has been reported. Here we present numerical and theoretical calculations of $A$…
The theory of epitaxial strain energy is extended beyond the harmonic approximation to account for large film/substrate lattice mismatch. We find that for fcc noble metals (i) directions 〈001〉 and 〈111〉 soften under tensile biaxial strain (unlike zincblende semiconductors) while (ii) 〈110〉 and 〈201〉 soften under compr…
We study how an axisymmetric drop of inviscid fluid breaks under the action of surface tension. The evolution of various initial shapes is calculated numerically using a boundary-element method, and finite-time breakage is observed in detail. The pinchoff region is shown to have lengths scaling as ${\ensuremath{\tau}}…
Microscopic models of the interaction between grain boundaries (GBs) and both dislocations and cracks are of importance in understanding the role of microstructure in altering the mechanical properties of a material. A recently developed mixed atomistic and continuum method is reformulated to allow for the examination…
The dynamic structure factor of fractal colloidal gels is shown to exhibit a stretched exponential decay to a finite plateau with an exponent of about 0.7. The value of the plateau depends on both initial particle volume fraction ${\ensuremath{\varphi}}_{0}$ and scattering wave vector. We show that this behavior resul…
The Kondo lattice Hamiltonian with ferromagnetic Hund's coupling as a model for manganites is investigated. The classical limit for the spin of the (localized) ${t}_{2g}$ electrons is analyzed on lattices of dimension 1, 2, 3, and $\ensuremath{\infty}$ using several numerical methods. The phase diagram at low temperat…
The relationship between spin state and metal−ligand bonding interactions in CpM(NO)X 2 species was investigated using density functional computational techniques. The geometries of CpM(NO)Cl 2 (M = Cr, Mo), CpCr(NO)(NH 2 )X, and CpCr(NO)(CH 3 )X (X = Cl, CH 3 ) were optimized at the DFT-B3LYP level for both the diama…
Diethylaminoethyl (DEAE) cottons having different % N were prepared by reacting cotton cellulose in the fabric form with diethylamine hydrochloride at different concentrations in the presence of sodium hydroxide. The modified samples so obtained were subjected to the graft polymerization reaction using methacrylic aci…
Poly(carboxylic acid)s have been used as crosslinking agents for wood pulp cellulose to increase the wet strength of paper. In this research, we evaluated the effects of two multifunctional carboxylic acids, i.e., 1,2,3,4-butanetetracarboxylic acid (BTCA) and poly(maleic acid) (PMA), on the wet strength retention, dim…
In situ reinforced binary and ternary polymer/polymer composites are obtained by the melt blending of poly(ethylene terephthalate) (PET), polyamide-6 (PA-6), and polyamide-66 (PA-66) in an extruder in the presence of a catalyst, followed by drawing of the extrudate and annealing of the drawn blends. The blends were st…
Vinyl-substituted silphenylene siloxane elastomers (VSPSEs) with variable vinyl content were synthesized using the disilanol−diaminosilane polycondensation method. High molecular weight elastomers were obtained by using carefully purified monomers. The polymers were characterized by gel permeation chromatography, diff…
The polymerization kinetics of zirconium propoxide (and in a few cases of titanium butoxide) were studied in various conditions by following the diffusion of an electroactive probe attached to the metal center. Two different probes were considered, implying the complexation of the metal alkoxides with bidentate ligand…
The temperature−concentration phase diagrams have been established for sPMMA gels prepared from toluene, chlorobenzene, and bromobenzene. In these three solvents polymer−solvent compounds are formed: one compound in toluene (two toluene molecules/three monomers) and two compounds in bromobenzene and chlorobenzene (two…
The adsorption of equimolar binary Lennard-Jones gas mixtures into single-walled carbon nanotubes is investigated using grand canonical Monte Carlo simulations. For mixtures whose species have different molecular diameters, the larger energetically favored species is adsorbed at higher temperatures. However, at lower…