Materials Literature
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The static adhesion of living L1210 cells (in serum-containing medium) to the surface of (styrene/methylmethacrylate) copolymers differing in styrene content (from 5% to 50% of styrene units) was investigated. The examination of wettability of the copolymer surfaces showed that the contact angle of water on the hydrop…
Slow diffusion of cobalt chloride with Na2[Fe(CN)5NO]-5H2O in aqueous solution produced crystals of Co[Fe(CN)5NO]-5H2O suitable for analysis by three-dimensional, single-crystal X-ray diffractometry. This polynuclear transition metal cyanide crystallized in the cubic space group Fm3m (No. 225, O5 h), a = 10.28 I (2)Å,…
The toughness increment resulting from the stress‐induced dilatational component of the t → m transformation is calculated for a zirconia‐toughened‐alumina (ZTA) composition containing a high proportion of tetragonal zirconia precipitates and is shown to agree very well with the experimental value. The good agreement…
This review of the chemistry and electrochemistry of the Hall-Heroult process discusses the composition and constitution of the electrolyte, phenomena occurring at the anode and cathode, the chemical behaviour of the carbon cell-lining, the mechanism of the loss of Faradaic efficiency, and matters of current concern f…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLow-valent titanium porphyrin complexes. Synthesis and structural characterization of the first titanium(II) porphyrin complex, (.eta.2-diphenylacetylene)titanium octaethylporphyrinL. Keith Woo, J. Alan Hays, Robert A. Jacobson, and Catherine L. DayCite this: Organometallics…
Vapor-deposited films prepared under low adatom mobility conditions commonly exhibit columnar structures. We present the scanning electron microscopy study of Cu films with a thickness around 3.7 μm deposited on rough Al2O3 ceramic substrates and smooth SiO2 substrates. The Cu films were deposited using the partially…
Abstract Poly(phenylene-chloroethylene) film was prepared by the vapor deposition polymerization of 1,9-dichloro[2.2]paracyclophane and was converted into fully extended π-conjugated poly (phenylene-vinylene) by thermal dehydrochlorination at 300 °C under nitrogen for 1 h.
Photoinduced absorption spectra for vibrational and electronic excitations have been investigated in a prototypical one-dimensional Peierls-Hubbard system, potassium tetracyanoquinodimethane crystals. Strong photoinduced-absorption signals and their temperature-and time-dependent characteristics are discussed in terms…
We have used x-ray photoelectron spectroscopy (XPS) to measure the valence band offset in situ for CdSe/ZnTe (100) heterojunctions grown by molecular-beam epitaxy. XPS measurements were performed for films of CdSe (100) and ZnTe (100), and for heterojunctions consisting of either ∼25 Å of CdSe grown on ZnTe or ∼25 Å o…
Silica soots were sintered under a reducing ambient to study the generation mechanism of the oxygen-deficient-type defects in silica glasses. Glasses sintered under H2/He gas mixtures or vacuum were prepared with an intent to produce oxygen-deficient centers. Two optical-absorption bands were generated in the silica g…
Ten Gomphonema taxa and four taxa of Gomphoneis from the upper Laurentian Great Lakes are considered. Gomphonema taxa include five new species and one new variety and a new record for the Great Lakes. Two new Gomphoneis taxa are described. SEM study of Gomphonema species indicates that all have occluded puncta. Occlus…
Abstract Polymerization of ε‐caprolactone initiated with dialkylaluminum alkoxides is a living system; formation of macrocyclics is fully depressed. Polymerization initiated with diethylaluminum alkoxide and diisobutylaluminum alkoxide proceeds on monomeric (deaggregated) active species, reversibly aggregating into tr…
Abstract 1,2-Dimethylindolylfulgides with 5-methylthio, 5-methoxy, or 5-dimethylamino group on the indole ring were synthesized and their photochromic properties were examined. Electron donating substituents lengthened the absorption maximum of the colored form and decreased the quantum yields of the photoreactions. T…
The digestive gland of Pecten maximus consists, as in other lamellibranchs, of numerous blindending tubules which communicate with the stomach by partially ciliated main ducts and non ciliated secondary ducts. The non-ciliated cells of the main ducts are characterized by a well developed brush border constituted by hi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal process for orientation of polyaniline filmsK. R. Cromack, M. E. Jozefowicz, J. M. Ginder, A. J. Epstein, R. P. McCall, G. Du, J. M. Leng, K. Kim, C. Li, and Cite this: Macromolecules 1991, 24, 14, 4157–4161Publication Date (Print):July 1, 1991Publication History Pub…
The interactions of a lyotropic liquid crystal with boundary amorphous glass surfaces are investigated using optical techniques. An unusual phenomenon is observed: the gliding of the director at the surface. A qualitative model is proposed to explain the experimental results.
We consider the problem of wave guiding by optical fibers with nematic liquid crystal cores. The dielectric properties of the core which govern wave guiding in the fiber are determined by the nematic director field. We focus on the problem of determining the configuration of the liquid crystal in a cylindrical cavity…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAlkyl iodide decomposition on copper surfaces: .alpha.-elimination and .beta.-hydride elimination from adsorbed alkylsCynthia J. Jenks, Chao Ming Chiang, and Brian E. BentCite this: J. Am. Chem. Soc. 1991, 113, 16, 6308–6309Publication Date (Print):July 1, 1991Publication Hi…
Sundström (1986) erected the genus Proboscia for solenoid diatoms whose valves tapered to a proboscis, but only assigned one species to it, the boreal Rhizosolenia alata Brightwell. We have found three species in the modem Antarctic phytoplankton that are affiliated to Proboscia. One is apparently identical to Sundstr…
Abstract Styrene‐butadiene‐styrene linear block copolymer (SBS) can be epoxidized with hydrogen peroxide in the presence of methyltrioctylammonium tetrakis (diperoxotungsto) phosphate(3‐) as the catalyst in a biphasic system. The effects of reaction time, temperature, solvent, the ratio of the organic phase to the aqu…