Materials Literature
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Abstract Molecular aggregation structure of poly(fluoroalkyl acrylate) [PFA-Cy, where y is the fluoromethylene number of the fluoroalkyl (Rf) groups] thin films was characterized by grazing-incidence X-ray diffraction (GIXD). In-plane diffractions corresponding to the hexagonal packing of the Rf groups were measured f…
Aqueous dispersions of fullerene C70-filled carbon nanotubes (C70@SWNTs or peapods) and empty single-walled carbon nanotubes (empty SWNTs) were prepared with the aid of trimethyl-(2-oxo-2-pyrene-1-yl-ethyl)-ammonium bromide (1), which is a carbon nanotube solubilizer. This is the first report describing the preparatio…
Dimetallic Schiff base-porphyrazine (pz) compounds, denoted 1[M(1); M(2); R], have been prepared, where metal ion M(1) is incorporated into the pz core, and metal ion M(2) is bound to a bis(5-tert-butylsalicylidenimine) chelate built onto two amino nitrogens attached to the pz periphery; R is a solubilizing group (eit…
A porous silica-based material with living cells lodged in macrocavities prepared in monolithic form: an original method to encapsulate an entire cell culture providing a near-natural environment inside an inorganic material.
We report here the structure of the putative chromo domain from MOF, a member of the MYST family of histone acetyltransferases that acetylates histone H4 at Lys-16 and is part of the dosage compensation complex in Drosophila. We found that the structure of this domain is a beta-barrel that is distinct from the alpha +…
The ultrasonically initiated batch miniemulsion copolymerizations of methyl methacrylate (MMA) and butyl acrylate (BA) are studied at different MMA:BA ratios (including homopolymerizations), and the physical properties and chemical composition of the polymers formed are investigated. Trends in the evolution of the par…
The effects of the molecular weight on the physical aging of polymers were investigated by means of differential scanning calorimetry (DSC) experiments in five PMMA samples with mass values across the entanglement mass M e . The Tool−Narayanaswamy−Moynihan (TNM) model and a recent configurational entropy approach were…
An antireflection film was prepared by spin-coating of poly(methyl methacrylate) (PMMA) solution in chloroform in the presence of small amounts of nonsolvent alkanes. When the vapor pressure of a nonsolvent was lower than that of chloroform, a dense skin layer was formed because of the rapid solvent evaporation during…
The monomer conversion dependence of the formation of the various types of defect structures in radical suspension polymerization of vinyl chloride was examined via both 1 H and 13 C NMR spectrometry. The rate coefficients for model propagation and intra- and intermolecular hydrogen abstraction reactions were obtained…
A central challenge for both the science and the technology of carbon nanotubes is the controlled assembly of devices. Here, we report a technique that allows us to place a nanotube with the desired properties in a predetermined location by direct mechanical transfer. We demonstrate single-tube and multiple-tube trans…
We model the exchange-correlation (XC) energy density of the Si crystal and atom as calculated by variational Monte Carlo (VMC) methods with a gradient analysis beyond the local density approximation (LDA). We find the Laplacian of the density to be an excellent predictor of the discrepancy between VMC and LDA energy…
We report on the characterization of sol-gel derived lithium niobate via trivalent chromium probe ions, a study that is motivated by recent reports on the synthesis of high quality sol-gel lithium niobate (LiNbO$_3$). In order to assess the quality of sol-gel derived LiNbO$_3$, we incorporate Cr$^{3+}$ during the hydr…
Path integral Monte Carlo simulations are applied to study dense atomic hydrogen in the regime where the protons form a Wigner crystal. The interaction of the protons with the degenerate electron gas is modeled by Thomas-Fermi screening, which leads to a Yukawa potential for the proton-proton interaction. A numerical…
We reveal the microscopic self-diffusion process of compact tri-interstitials in silicon using a combination of molecular dynamics and nudged elastic band methods. We find that the compact tri-interstitial moves by a collective displacement, involving both translation and rotation, of five atoms in a screw-like motion…
In this letter, we report a one-step templating synthetic strategy to prepare aligned TiO2 nanotube and nanowire arrays on Si substrate from a solution at ambient temperature. The deposition of TiO2 and the selective-etching of the ZnO template proceeded at the same time through the careful control of process paramete…
In this paper, we present models of Ge-Se glasses heavily doped with Ag obtained from {\it ab initio} simulation and study the dynamics of the network with an emphasis on the motion of Ag$^+$ ions. The models are analyzed with partial pair correlation functions, static structure factors and novel wavelet techniques. T…
Semiconductor quantum dots (QDs) have been used in a simple fluorometric assay to detect single cells of the pathogenic Escherichia coli O157:H7 serotype. Composed of CdSe/ZnS core/shell QDs conjugated to streptavidin, this system exhibits 2 orders of magnitude more sensitivity than a similar assay using a common orga…
A method for growing vertical ZnO nanowire arrays on arbitrary substrates using either gas-phase or solution-phase approaches is presented. A approximately 10 nm-thick layer of textured ZnO nanocrystals with their c axes normal to the substrate is formed by the decomposition of zinc acetate at 200-350 degrees C to pro…
This feature article highlights work from the authors' laboratories on the synthesis, assembly, reactivity, and optical applications of metallic nanoparticles of nonspherical shape, especially nanorods. The synthesis is a seed-mediated growth procedure, in which metal salts are reduced initially with a strong reducing…
O presente trabalho forma parte de um estudo sobre as diatomáceas do perifiton da bacia alta do Rio Sauce Grande, águas acima da Represa Paso de las Piedras, como base para a utilização destes organismos como indicadores de qualidade da água. As amostras foram coletadas no período de agosto- setembro de 2000 em 14 est…