Materials Literature
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The coordination number of the pore network of a mesoporous solid can be determined from its nitrogen adsorption and desorption isotherms, using an analysis method based on percolation theory. However, measurement of these isotherms is time-consuming and problematical very close to the bulk condensation pressure of ni…
A novel series of poly( N -vinyl-2-pyrrolidone)-protected nanometer-sized Cu/Pd alloy colloids have been prepared by a polyol reduction method. These colloids, having high molar fractions of Cu ( x = 0.99−0.80), show remarkable stability, as good as a Pd colloid. Transmission electron microscopy and high-resolution tr…
Pyrrole-2,4-dicarboxaldehydes 13a − c were condensed with a tripyrrane dicarboxylic acid 12 in 1% TFA−CH 2 Cl 2 to give, following oxidation with 0.1% FeCl 3, a series of “etio-type” N-confused porphyrins 14a − c . Excellent yields were obtained when the diformylpyrrole possessed a 5-alkyl substituent, although the pr…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis and Catalytic Activity of Unimolecular Dendritic Reverse Micelles with "Internal" Functional GroupsMarcelo E. Piotti, Felix Rivera,, Risha Bond, Craig J. Hawker, and Jean M. J. FréchetView Author Information IBM Almaden Research Center 650 Harry Road, San Jos…
We present semi-classical and quantized hydrodynamic models to obtain the quadratic electronic response of a plane-bounded electron gas. Explicit expressions for the dynamic image potential experienced by charged particles moving near a jellium surface are derived, up to third order in the projectile charge. These exp…
The extinction profiles as well as the hyper Rayleigh scattering signal of a highly monodisperse 22 nm diameter gold colloidal sol in the presence of pyridine have been measured. A strong enhancement of the HRS signal is observed in the presence of small amounts of pyridine. The relationship between the extinction spe…
An immunoassay readout method based on surface-enhanced Raman scattering (SERS) is described. The method exploits the SERS-derived signal from reporter molecules that are coimmobilized with biospecific species on gold colloids. This concept is demonstrated in a dualanalyte sandwich assay, in which two different antibo…
Solid state chemistry molecular clusters (including synthesis, reacitvity, and properties) metal clusters in catalysis nanomaterials theoretical aspects.
A knowledge of the mineralogy of hydrocarbon-bearing rocks is essential in the interpretation of reservoir rocks for petroleum exploration and production. The mineralogical effects on the characteristics of reservoir rocks are often profound, and some of the affected properties are listed in Table 1. Several technique…
The pure translation (TR) imaginary-frequency (or unstable) instantaneous normal modes (INM), which we have proposed as representative of barrier crossing and diffusion, are obtained for seven densities and eight temperatures of supercooled and near-melting liquid CS2 via computer simulation. The self-diffusion consta…
The energy landscape model of the glass transition has received increasing attention, due to its potential for providing a thermodynamic interpretation of the dynamics of glass-forming liquids. Herein, the idea that the temperature-dependence of the dynamics near the glass temperature (“fragility”) can be related to t…
Molecular dynamics simulations are used to explore the spatial fluctuations associated with structural relaxation and particle transport in a supercooled binary mixture in two dimensions. The study includes (i) the characterization of heterogeneities in the local particle dynamics in terms of their length scale and li…
We use atomistic simulations with an empirical potential (EAM) to study the elastic effects of heteroepitaxial islands on adatom diffusion. We measure the diffusion barrier on pure stressed substrate and near a misfit island, as well as the detachment barrier from islands of different size.
This Comment concerns the effective dielectric constant for 2D photonic crystal. We show that even in the limit of very high dielectric constant of photonic crystal's "atoms", static and quasistatic approaches give the same results, unlike it was claimed by Nicorovichi et al, PRL, 75, 1507 (1995).
The dynamics of block copolymer micelles, with a glassy polystyrene core and polyisoprene corona, in a matrix of linear entangled polyisoprene (PI) chains, has been investigated by forced Rayleigh scattering (FRS), dynamic mechanical measurements, and dielectric relaxation spectroscopy. The concentration of micelles h…
Mass transport of six food aroma components, D-limonene, n-decane, ethyl caproate, phenylethanol, 1-hexanol, and hexanal, through three sealable polymer films suitable for direct food contact, ultra-low-density polyethylene (ULDPE), ionomer (ION), and modified polyester (mPET), was analyzed by permeation experiments.…
The enhancement of the NO/carbon reduction reactions by carbon monoxide has been demonstrated for carbons of widely varying nature (coal char, phenolic resin-derived char and graphite). The evidence supports enhancement of NO reduction via a carbon-surface-catalyzed reaction such as NO + CO → 1/2N 2 + CO 2 . This reac…
The synthesis, spectral and structural characterization of meso -aryl sapphyrins and rubyrins containing heteroatoms such as S, O, Se in addition to pyrrole nitrogens are reported. The synthesis of the desired expanded porphyrins has been achieved using a single precursor, the modified tripyrranes containing heteroato…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTOn−Off Control of Enzymatic Activity Synchronizing with Reversible Formation of Supramolecular Assembly from Enzyme and Charged Block CopolymersAtsushi Harada and Kazunori KataokaView Author Information Department of Materials Science, Graduate School of Engineering, T…
We report the design of polymer/lipid composite films on polarizable indium−tin−oxide (ITO) electrodes and the characterization of their electrical properties by impedance spectroscopy. The polymer films separating the solid surfaces and the lipid membranes were composed of “ hairy-rod ” macromolecules and provided a…