Materials Literature
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Biological systems can produce extraordinary inorganic structures and morphologies. The mechanisms of synthesis are poorly understood but are of great interest for engineering novel materials. We use spectromicroscopy to show that microbially generated submicrometer-diameter iron oxyhydroxide (FeOOH) filaments contain…
In this paper we present a detailed theory of electron and thermoelectric transport perpendicular to heterostructure superlattices. This nonlinear transport regime above barriers is also called heterostructure thermionic emission. We show that metal-based superlattices with tall barriers can achieve a large effective…
Abstract The oxygen permeation resistance of polyethylene (PE), polyethylene/ethylene vinyl alcohol copolymer (PE/EVOH), polyethylene/modified ethylene vinyl alcohol copolymer (PE/MEVOH), and polyethylene/modified polyamide–ethylene vinyl alcohol copolymer (PE/MPAEVOH) bottles was investigated. The oxygen permeation r…
Abstract A generally applicable stoichiometric and kinetic model was developed for the polymerization of dimer fatty acids with ethylenediamine. The rate equations were second‐order before 90% conversion and were used between 405 and 475 K. The parameters of the rate equations were determined with nonlinear regression…
In a spin: In the three-dimensional oxalate network structures of composition [CoxMII1-x(bpy)3][MICr(ox)3], the spin state of the [Cox(bpy)3]2+ complex can be tuned by means of chemical pressure. With MI=Na it is a classic high-spin complex. Substitution of Na by Li stabilises the complex and it becomes a spin-crossov…
We develop a scattering matrix approach for the numerical calculation of resonant states and Q values of a nonideal optical disk cavity with an arbitrary shape and with an arbitrary varying refraction index. The developed method is applied to study the effect of surface roughness and inhomogeneity of the refraction in…
The electric-field gradient at the halide site is calculated in several compounds of Cl, Br, and I. The ab initio full-potential linear-augmented plane-wave method is employed with the generalized gradient approximation for exchange and correlation effects. The nuclear quadrupole moments of ${}^{35}\mathrm{Cl},$ ${}^{…
Abstract The compatibilization efficiency of two styrene‐butadiene‐styrene triblock copolymers with short (SB1) and long (SB2) styrene blocks was studied in polystyrene (PS)–polypropylene (PP) blends of composition 20, 50, and 80 wt % PS. The supramolecular structure of the blends was determined by small‐angle X‐ray s…
Fluorescent clusters : The agglomeration of Ag clusters resulting from the codeposition of Ag and Ar atoms onto a cold substrate is accompanied by light emission from deexcitation of intermediately formed electronically excited Ag 2 * and Ag 3 * species. The yield of chemiluminescence was investigated as a function of…
Abstract Vulcanized composites of chloroprene rubber (CR) with cellulose II (Cel II) as a filler were investigated. Cel II, obtained by the coagulation of cellulose xanthate, was incorporated in the rubber by the traditional method. The filler content varied from 0 to 30 phr. For comparison purposes, carbon black (CB)…
Abstract This study examined the mechanism on the surface activation of hydrophilic polyvinyl siloxane impression materials incorporated with nonionic surfactants. Hydrophilic polyvinyl siloxane impression materials were prepared with a polydimethylsiloxane composition and nonionic surfactants. The surfactants used we…
Glasses of the composition 30(Li,Na)2O,xB203,(70-x) Te02 (20 ≤ x ≤ 50) have been prepared using the melt quenching method. Properties of these glasses have been measured and examined for the presence of mixed alkali effect (MAE). Infrared, Raman and 11B HR MAS NMR spectroscopies have been used to investigate the stru…
Poly[(2,2'-bipyridine)tetrakis(imidazolato)diiron(II)] was synthesized by the reaction of ferrocene with imidazole in an excess of 2,2'- bipyridine in a Carius tube at 130 degrees C. Dc magnetic susceptibility studies at an applied field of 1000 G reveal that on cooling from room temperature, the material undergoes tw…
The stability under pressure of charge order $({\mathrm{Ni}}^{3+\ensuremath{\delta}}/{\mathrm{Ni}}^{3\ensuremath{-}\ensuremath{\delta}})$ in ${\mathrm{YNiO}}_{3}$ has been investigated by infrared spectroscopy and x-ray synchrotron diffraction studies up to 23 GPa. We report the observation of a sudden electronic and…
Abstract A simple friction factor has been devised to characterize the frictional properties of textile materials. The friction factor enables universal comparisons among different textile materials. A poly(methyl methacrylate) sled has been used as a standard friction substrate to characterize the friction of a woven…
Subpixel structures found in medical monochrome active-matrix liquid crystal displays (AMLCDs) affect noise estimates measured with conventional methods. In this work, we discuss methods that identify sources of noise and permit the comparison of luminance noise estimates across technologies independent of pixel desig…
Abstract We have measured the time evolution of the self‐assembly process in perpendicular‐oriented cylindrical‐phase diblock copolymer thin films using statistical analysis of high‐resolution scanning electron microscope (SEM) images. Within minutes of annealing above the polymer glass‐transition temperature, microph…
Absorption spectra, luminescence spectra and luminescence decay time are investigated for a borosilicate glass containing low 0.1 wt% Ce3+ and high 15 wt% Tb3+ concentrations, together with the time-resolved luminescence. A broad absorption band due to parity allowed f → d transition is observed for Ce3+. Sharp absorp…
Abstract Solution impregnations, pulltrusion and film stacking are widely used methods to prepare thermoplastic composite materials. Extruders are used to melt the polymer and to incorporate fibers into the polymer in order to modify physical properties. In this article, the compounding of colloidal silica nanoparticl…
We have designed a tunable, oblique-incidence resonant grating filter that covers the C band as an add-drop device for incident TE-polarized light. We tune the filter by tilting a microelectromechanical systems platform onto which the filter is attached. The fabrication tolerances as well as the role of finite inciden…