Materials Literature
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We summarize our recent results of scattering hyperthermal (1–15 eV) rare-gas atoms from single-crystal semiconductors. These include collisional excitation of carriers in the semiconductor, the ejection of charged and neutral surface particles, and the projectile scattering distributions characteristic of the strongl…
The Whittier Narrows earthquake (Richter Magnitude 5.9), which struck Southern California in the morning of October 1, 1987, caused some $20.5 million damage to various engineered buildings at California State University, Los Angeles and the death of a student due to a falling precast concrete panel. Peak ground accel…
Abstract The free‐volume theory of diffusion is used to analyze the temperature dependence of solvent self‐diffusion coefficients both above and below the glass transition temperature at concentrations removed from the pure polymer limit. The glass transition can have a pronounced effect on the temperature dependence…
Time-resolved light scattering studies have been undertaken for elucidating the dynamics of phase separation in aqueous HPC (hydroxypropyl cellulose) liquid-crystalline solutions. The HPC/water system phase separates during heating and returns to a single phase upon cooling. The phase diagram of thermally induced phas…
The molecular dynamics computer simulation technique has been used to study the atomic level structure at the vitreous silica surface and the effect that this surface structure has on the early stages of adsorption of K and Li ions. K ions preferentially adsorb at nonbridging oxygen (NBO), often diffusing over the sur…
Abstract Cation exchange capacity (CEC) and cation‐exchange equilibria involving Na, K, and Ca were measured on the <50µm fraction of Cecil sandy loam soil (Typic Hapludult) at pH values between 4 and 8. This was achieved by equilibrating the soil separate in acetate buffers followed by equilibration in 0.1 M chlor…
A set of programs has been developed for computing aberrations caused by small imperfections in the construction and alignment of electrostatic lenses. The programs predict the beam displacement and coma caused by misalignments and tilts, and the astigmatism caused by ellipticities, of each electrode. Any number of el…
Abstract The pyrolyses of homologous poly(alkyl acrylate)s is reported with identification of the major pyrolyses products. A mechanism involving random homolytic scission of the chain followed by a series of intermolecular and intramolecular transfer reactions has been proposed for poly(methyl acrylate) by Cameron an…
We have studied the effect of electric fields on the blue phase III (BPIII) of chiral liquid crystals. A temperature--electric-field phase diagram is presented and the behavior of the BPIII selective reflections over this diagram is shown. The selective reflection consists of a broad peak situated on a sloping backgro…
The transport of water in silicate melts is examined from a theoretical point of view, taking into account the presence of both H2O and OH-1 species. It was assumed that only H2O molecules may diffuse and that a constitutive relationship between the number density \documentclass{aastex} \usepackage{amsbsy} \usepackage…
InP and InGaAs electronic devices are subject to deterioration of their properties upon exposure to air, moisture, and irradiation due to the instability of their surfaces. Attempts to protect device surfaces by overcoating them with a plasma deposited protective coating are frustrated by a marked deterioration of the…
A thin-film technique has been developed for vacuum fabrication of mirrors with Gaussian reflectivity profiles. Samples with diameters from 2 to 8 mm and assigned maximum reflectivities for visible or near-IR wavelengths have been made and their optical properties evaluated. By properly choosing both the geometry of t…
The sodium salt of the dinucleoside phosphate d(GpG), dissolved in water, forms two mesophases which have been characterized, by optical microscopy, as being of the cholesteric (columnar chiral nematic, N∗) and hexagonal (M) type.
Experiments were performed to clarify the role of metallic fuel additives in relation to soot suppression in a well defined laboratory-scale diffusion flame. Principal emphasis was given to three alkaline-earth metals; namely, Ba, Sr and Ca. The experiments included Cu, Sn, Li, Na and K as well. but only to the extent…
Abstract The solid state of the complex between poly(acrylic acid) (PAA) and poly(ethylene oxide) (PEO), and that between poly(methacrylic acid) (PMAA) and PEO formed via hydrogen‐bonding was studied by differential‐scanning calorimetric (DSC) and by Fourier‐transform infrared (FT–IR) spectroscopic measurements. Melti…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTriplet-state formation of porphycenes: intersystem crossing versus sensitization mechanismsHaim Levanon, Moshe Toporowicz, Hanna Ofir, Richard W. Fessenden, Paritosh K. Das, Emanuel Vogel, Matthias Koecher, and Kakumanu PramodCite this: J. Phys. Chem. 1988, 92, 9, 2429–2433…
The interaction of oxygen with the surface of a Pt alloy containing ∼20 at. % of cobalt was studied by low-energy electron diffraction (LEED) and x-ray photoelectron spectroscopy (XPS). At this composition, cobalt was found to be randomly substituted in the Pt fcc lattice both in the bulk and at the surface. [111] and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-resolution electron energy loss spectroscopic study of carbon dioxide adsorbed on rhenium(0001)M. Asscher, C. T. Kao, and G. A. SomorjaiCite this: J. Phys. Chem. 1988, 92, 10, 2711–2714Publication Date (Print):May 1, 1988Publication History Published online1 May 2002Pub…
Their absorption spectrum of both single crystals and powdered samples of acetanilide (a model system for proteins) has been studied in the amide i region, where a narrow band has been identified as a highly trapped soliton state. The powder-sample spectra have been decomposed using four Lorentzian bands. A strong tem…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymer diffusion in melt blends of low and high molecular weightStanley F. Tead and Edward J. KramerCite this: Macromolecules 1988, 21, 5, 1513–1517Publication Date (Print):May 1, 1988Publication History Published online1 May 2002Published inissue 1 May 1988https://doi.org/…