文献浏览

Noticias

TABLE OF CONTENTS

The Effect of Impregnation on the Microstructure of Long Fibre Reinforced Thermoplastic Composites and Their Consequence on Deformation and Toughness

Influence of petrographical characterístics in the penetration of consolidants in porous building stones

This paper describes a study of the penetration capacity of a consolidant frequently used in restoration —ethyl silicate— applied to two monumental stones with different porosities and pore geometries: the Hontoria limestone (Burgos) and the Laspra dolomite (Asturias). The relation between mode of application and pene…

Editorial

Low-temperature neutron powder diffraction study of copper chromium thiophosphate (CuCrP2S6): observation of an ordered, antipolar copper sublattice

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLow-temperature neutron powder diffraction study of copper chromium thiophosphate (CuCrP2S6): observation of an ordered, antipolar copper sublatticeV. Maisonneuve, V. B. Cajipe, and C. PayenCite this: Chem. Mater. 1993, 5, 6, 758–760Publication Date (Print):June 1, 1993Publi…

Calculating the helical twisting power of dopants in a liquid crystal by computer simulation

The helical twisting power determines the pitch of the helical structure produced by introducing a given concentration of chiral dopant molecules to a nematic liquid-crystal phase. By using alternative, twisted, periodic boundary conditions, and measuring the relative chemical potentials of right- and left-handed dopa…

Electron-correlation energies and the structure ofSi13

A simple physical model for the difference in correlation energies of ${\mathrm{Si}}_{13}$ in icosahedral and trigonal prismatic structures yields semiquantitative estimates for this difference, which show that it can stabilize the icosahedral structure relative to the trigonal one by as much as 0.2 eV/electron, or \e…

Thermodynamics of phase transitions in current-carrying conductors

This work studies the thermodynamics of phase transitions of the first kind in current-carrying conductors when these transitions are accompanied by a sharp change of the electrical conductivity. It is shown that the critical current in the normal conductor, i.e., the current that generates the critical pressure, may…

Interlamellar covalent grafting of organic units on kaolinite

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterlamellar covalent grafting of organic units on kaoliniteJames J. Tunney and Christian DetellierCite this: Chem. Mater. 1993, 5, 6, 747–748Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June 1993https://doi.org/10.1…

Convergence of the coupled-wave method for metallic lamellar diffraction gratings

Numerical evidence is presented that shows that, for metallic lamellar gratings in TM polarization, the coupled-wave method formulated by Moharam and Gaylord [ J. Opt. Soc. Am. A3, 1780 ( 1986)] converges slowly. (In some cases, for achieving a relative error of less than 1% in diffraction efficiencies, the number of…

Electrochemical applications of the bending beam method. 2. Electroshrinking and slow relaxation in polypyrrole

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemical applications of the bending beam method. 2. Electroshrinking and slow relaxation in polypyrroleQibing Pei and Olle InganaesCite this: J. Phys. Chem. 1993, 97, 22, 6034–6041Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Publ…

Transitions and instabilities in liquid crystal elastomers

Solid nematic liquids, formed by cross-linking polymer liquid crystals into elastomers, are shown to display novel and complex elasticity. The internal (nematic) direction suffers a barrier to its rotation and this couples to standard elasticity. By considering imposed strains we illuminate this elasticity and also de…

Preparation and characterization of ceria under an oxidizing atmosphere. Thermal analysis, XPS, and EPR study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and characterization of ceria under an oxidizing atmosphere. Thermal analysis, XPS, and EPR studyEdmond Abi-aad, Rafeh Bechara, Jean Grimblot, and Antoine AboukaisCite this: Chem. Mater. 1993, 5, 6, 793–797Publication Date (Print):June 1, 1993Publication History…

Solid‐State Chemistry with Nonmetal Nitrides

Abstract Among the nonmetal nitrides, the polymeric binary compounds BN and Si 3 N 4 are of particular interest for the development of materials for high‐performance applications. The outstanding features of both substances are their thermal, mechanical, and chemical stability, coupled with their low density. Because…

Regulation of the Bacillus subtilis alsS, alsD, and alsR genes involved in post-exponential-phase production of acetoin

Acetoin is a major extracellular product of Bacillus subtilis grown on glucose and other fermentable carbon sources. The enzymes responsible for the formation of acetoin, acetolactate synthase, and acetolactate decarboxylase are synthesized in detectable amounts only in cells that have reached stationary phase. We hav…

Determination of absorption coefficients for concentrated samples by fluorescence detection

A method to determine the absorption coefficient near the onset of core-electron transitions for concentrated samples using fluorescence-yield (FY) detection is presented. Measuring the FY signal for different experimental geometries, we are able to calculate the true absorption coefficient. Thus we are able to correc…

Performance of Solid Oxide Fuel Cell Using Proton and Oxide Ion Mixed Conductors Based on BaCe1 − x Sm x O 3 − α

ceramics were synthesized and their ionic conduction was investigated. These ceramics showed protonic and oxide ionic mixed conduction under fuel cell condition. While protonic conduction was predominant below 1027 K, oxide ionic conduction became significant as the temperature increased. Using these oxides as solid e…

Structural, thermal, and electrical characterization of layered nanocomposites derived from sodium-montmorillonite and polyethers

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural, thermal, and electrical characterization of layered nanocomposites derived from sodium-montmorillonite and polyethersJinghe Wu and Michael M. LernerCite this: Chem. Mater. 1993, 5, 6, 835–838Publication Date (Print):June 1, 1993Publication History Published onlin…

Thermal conductivity of diamond between 170 and 1200 K and the isotope effect

Measurements on the thermal conductivity of natural and synthetic single-crystal diamond are presented over a wide temperature range. The large isotope effect reported previously has been confirmed. The data have been analyzed using both the Debye model of thermal conductivity, which ignores the N processes, and the C…