Materials Literature
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The structure of the growth lines in the shell of the red abalone, Haliotis rufescens, has been characterized by X-ray diffraction analysis and by scanning and transmission electron microscopy. The growth lines consist of a blocklike microstructure and a spherulitic microstructure, separated by a green organic matrix…
Abstract A novel phosphorus‐containing aralkyl novolac (Ar‐DOPO‐N) was prepared from the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) first with terephthaldicarboxaldehyde and subsequently with phenol. The chemical structures of the synthesized compounds were characterized with Fourier transfo…
Vigorous stirring of a biphasic mixture containing hexadecylaniline in chloroform and aqueous chloroauric acid results in the formation of gold nanoparticles of controllable size in the organic phase.
Many naturally occurring biomaterials are composed of laminated structures in which layers of beta-sheet proteins alternate with layers of inorganic mineral. These ordered laminates often have structural and mechanical properties that differ significantly from those of nonbiological materials. An important step in the…
Human phenylalanine hydroxylase (hPAH) is a tetrameric enzyme that catalyzes the hydroxylation of L-phenylalanine (L-Phe) to L-tyrosine; a dysfunction of this enzyme causes phenylketonuria. Each subunit in hPAH contains an N-terminal regulatory domain (Ser2-Ser110), a catalytic domain (Asp112-Arg410), and an oligomeri…
We present a continuum theory model of switching in a bistable nematic liquid crystal device. The bistability of the device investigated relies on the fact that one of the cell surfaces exhibits two stable anchoring states, that is, two surface director orientations are locally stable. Since the other surface exhibits…
We report the results of an investigation into the rheology of solutions of natural spider silk dope (spinning solution). We demonstrate that dilute dope solutions showed only shear thinning as the shear rate increased while more concentrated solutions showed an initial shear thinning followed by a shear thickening an…
An inverted emulsion process for the synthesis of the emeraldine salt of polyaniline using a novel oxidizing agent, namely benzoyl peroxide, is described. The polymerization is carried out in a nonpolar solvent in the presence of a functionalized protonic acid (sulfosalicylic acid) as the dopant and an emulsifier (sod…
Abstract The commercial grade of isotactic polypropylene was modified by a specific β‐nucleating agent in a broad concentration range. The supermolecular structure of the specimens prepared by injection molding was characterized by X‐ray scattering and correlated with mechanical behavior. It was found that at a critic…
The classical vibrational modes are calculated for a thin-walled hollow cylinder of isotropic material. An analytical solution is obtained for all of the modes. The results are applied to calculate the low-frequency vibrational modes of a single-wall carbon nanotube. Analytical formulas are obtained for the Raman freq…
We investigate the effect of quantum confinement on the electronic structure of diluted magnetic semiconductor Ga 1 - x Mn x As using a combination of tight-binding and density functional methods. We observe half metallic behavior in the clusters as well as a strong majority-spin Mn d−As p hybridization down to sizes…
A continuum dynamical model is developed to determine the morphological and compositional instabilities on the free surface of heteroepitaxial alloy films in the absence of growth. We use linear stability analysis to study the early nonequilibrium processes of surface evolution, and calculate the stability conditions…
The mechanisms of stability or instability in the strained alloy film growth are of intense current interest to both theorists and experimentalists. We consider dislocation-free, coherent, growing alloy films which could exhibit a morphological instability without nucleation. We investigate such strained films by deve…
We study the fracture surface of three dimensional samples through a model for quasi-static fractures known as Born Model. We find for the roughness exponent a value of 0.5 expected for ``small length scales'' in microfracturing experiments. Our simulations confirm that at small length scales the fracture can be consi…
Experimental data are reported on the elastoplastic response of and moisture diffusion through a vinyl ester resin-montmorillonite clay nanocomposite with various amounts of filler. Two simple models are developed for the elastoplastic behavior of a nanocomposite and for the anomalous diffusion of penetrant molecules.…
We explore and discuss the influence of the geometrical parameters of a compound diffraction grating on the generation of pi resonances, which appear when the surface is illuminated by a p-polarized plane wave. We consider a grating with rectangular grooves, and analyze the evolution of pi resonances when depth, width…
Abstract Dissolution and mutual diffusion of poly( N ‐vinylpyrrolidone) (PVP) in short‐chain poly(ethylene glycol) PEG400 were studied by wedge microinterferometry over the temperature range of 40–100°C. Successive photographs of interference patterns measured at λ = 546 nm with an optical microscope at 130× magnifica…
Rhodium acetonitrile complexes have been immobilised in the mesoporous silica MCM-41 by pore volume impregnation of a solution of the compound [Rh2(CH3CN)10](BF4)4 in acetonitrile. Powder XRD and N2 adsorption–desorption analysis of the derivatised material confirmed that the textural properties of the hexagonally ord…
We observed interesting structures during phase transformations of lysozyme solutions. The process begins with the separation of a protein-rich liquid phase in the form of droplets. The droplets fall to the bottom of the chamber in a few minutes, and on the scale of an hour they begin to merge, forming an interconnect…
Abstract Investigations into the processing characteristics and physicomechanical properties of natural rubber (NR) modified with liquid natural rubber (LNR) were carried out. Liquid natural rubber samples (of different molecular weights) were first produced by depolymerization of natural rubber latex (NRL), using nit…