Materials Literature
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For nonadiabatic electron-transfer reactions, it is common to make a Condon approximation assumption that the mixing matrix element is independent of nuclear geometry. We test the validity of the Condon approximation using Mulliken-Hush analysis applied to the biphenyl alcohol molecule at various geometries. Calculati…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSupramolecular Catalysis of Olefin [2 + 2] PhotodimerizationDario M. Bassani, Vincent Darcos, Sarah Mahony, and Jean-Pierre DesvergneView Author Information Laboratoire de Chimie Organique et Organométallique CNRS UMR 5802 Université Bordeaux 1 33405 Talence Cedex, Fra…
Stable dispersions of nanosilica ranging in size between 8 and 11 nm were coated with tert -butyl acrylate polymer by in situ polymerization of monomer adsorbed on the particles in 2-propanol. The system was developed for use in the encapsulated inorganic resist technology. To achieve a high coating efficiency, silica…
As the potential for applications utilizing oriented thin films grows, so grows the need for accurate, reliable measurements of molecular orientation and surface coverage. Recent work in our laboratory has been directed toward this goal. In this paper the theoretical and experimental effects of surface roughness and t…
A mechanical-loading stage operating inside a scanning electron microscopy (SEM) was used to realize the sliding between nested shells of multiwalled carbon nanotubes (MWCNTs). A stick−slip motion and a smooth pullout motion were observed for the two separate MWCNTs studied. A model that includes the shear interaction…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSteam-Stable Aluminosilicate Mesostructures Assembled from Zeolite Type Y SeedsYu Liu, Wenzhong Zhang, and Thomas J. PinnavaiaView Author Information Department of Chemistry, Michigan State University East Lansing, Michigan 48824 Cite this: J. Am. Chem. Soc. 2000, 122,…
Mesostructured intercalates belonging to the class of solid acids known as porous clay heterostructures (PCH) have been prepared through the surfactant-directed assembly of mesoporous silica within the galleries of synthetic saponite clays with targeted layer charge densities in the range x = 1.2−1.7 e - units per Q +…
Recent experiments by Kiritani et al. have revealed a surprisingly high rate of vacancy production during high-speed deformation of thin foils of fcc metals. Virtually no dislocations are seen after the deformation. This is interpreted as evidence for a dislocation-free deformation mechanism at very high strain rates.…
A globally-adaptive curvilinear coordinate formalism is shown to be easily convertible to a class of curvilinear transformations locally optimized around atom sites by a few parameters. Parameter transferability is established for a demanding test case, and the results of the two methods are shown to be comparable. Co…
We develop coarse-grained force fields for poly (vinyl alcohol) and poly (acrylic acid) oligomers. In both cases, one monomer is mapped onto a coarse-grained bead. The new force fields are designed to match structural properties such as radial distribution functions of various kinds derived by atomistic simulations of…
Using an efficient optimal control scheme to determine the exciting fields, we theoretically demonstrate the optical creation of vibrational intrinsic localized modes (ILMs) in anharmonic perfect lattices with realistic interatomic potentials. For systems with finite size, we show that ILMs can be excited directly by…
We have grown single crystals of electron doping system Ca2-xLaxRuO4 (0.00 <= x <= 0.20) by a floating zone method. The first order metal/non-metal transition and canted antiferromagnetic ordering occur for 0.00 < x < 0.15, similar to those in the bandwidth controlled system Ca2-xSrxRuO4 (CSRO). However, comparing wit…
The utilisation of crystalline semiconductor materials as detectors and devices operating in high radiation environments, at the future particle colliders, in space applications, in medicine and industry, makes necessary to obtain radiation harder materials. Diamond, SiC and different AIIIBV compounds (GaAs, GaP, InP,…
A simplified theoretical model for the constant-magnitude steady-state surface photovoltage (SPV) technique is developed. Emphasis is placed on the determination of the minority carrier diffusion length L in the particular case for which the sample thickness is quite lower than the true value of L. The model is derive…
The origin of ferroelectricity in KH_2PO_4 (KDP) is studied by first-principles electronic structure calculations. In the low-temperature phase, the collective off-center ordering of the protons is accompanied by an electronic charge delocalization from the "near" and localization at the "far" oxygen within the O-H...…
The magnetic behaviour of nanoparticles of antiferromagnetic ferritin has been investigated by 57Fe Mossbauer absorption spectroscopy and magnetisation measurements, in the temperature range 2.5K-250K and with magnetic fields up to 7T. Samples containing nanoparticles with an average number of Fe atoms ranging from 40…
Magnetic and magnetostrictive properties have been investigated for amorphous (Tb 0.27 Dy 0.73 )(Fe x Co 1- x ) 2 thin films. An increase in the 3d magnetic moment and Curie temperatures higher than 550 K due to the enhancement of T-T interactions (T = transition metal) in substituted (Fe, Co) alloys were found. A wel…
We report the electron transport studies in the rhombohedral LaMn 1- x Al x O 3+δ series (0⩽ x ⩽20%) of samples. Though all the samples are ferromagnetic below a transition temperature ( T C ), only the samples with x ⩽5% exhibit a metal-insulator transition (MIT) at T C while the samples with x ⩾10% are all semicondu…
The explosive charge within a landmine is the source for a mixture of chemical vapors that form a distinctive 'chemical signature' indicative of a landmine. The concentration of these compounds in the air over landmines is extremely low, well below the minimum detection limits of most field- portable chemical sensors.…
Nature tries to minimize the surface area of a soap film through the action of surface tension. The process can be understood mathematically by using differential geometry, complex analysis, and the calculus of variations. This book employs ingredients from each of these subjects to tell the mathematical story of soap…