Materials Literature
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The electronic structure, the linear optical properties, and the structural properties of α‐Al 2 O 3 in the corundum structure are studied by means of first‐principles local density calculations. An indirect band gap of 6.29 eV is obtained, which is almost the same as the direct band gap of 6.31 eV at Γ. The calculate…
Microwave discharges (2.45 GHz) have been generated in C60-containing Ar. The gas mixtures were produced by flowing Ar over fullerene-containing soot at a variety of temperatures. Optical spectroscopy shows that the spectrum is dominated by the d 3Πg–a 3Πu Swan bands of C2 and particularly the Δv=−2, −1, 0, +1, and +2…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew Series of Multifunctionalized Nickel(II)-Cyclam (Cyclam = 1,4,8,11-Tetraazacyclotetradecane) Complexes. Application to the Photoreduction of Carbon DioxideEiichi Kimura, Senji Wada, Mitsuhiko Shionoya, and Yohko OkazakiCite this: Inorg. Chem. 1994, 33, 4, 770–778Publicat…
ADVERTISEMENT RETURN TO ISSUEArticleNEXTPoly[(amino acid ester)phosphazenes]: Synthesis, Crystallinity, and Hydrolytic Sensitivity in Solution and the Solid StateHarry R. Allcock, Shawn R. Pucher, and Angelo G. ScopelianosCite this: Macromolecules 1994, 27, 5, 1071–1075Publication Date (Print):February 1, 1994Publicat…
We review our current understanding of the mechanical, electronic and structural properties of the element uranium, with the focus on the low-temperature regime in which the α-phase is stable. We start with a historical perspective, as the need for understanding the metallurgy of uranium so that its use as a nuclear f…
A model, based on a simple axisymmettical fiber/interphase/ matrix assembly, is derived to depict the oxidation behavior of ID‐SiC/C/SiC composites within the temperature range 900–1300°C and for 10 < P O2 < 100 kPa. It takes into account (i) the changes versus time of the geometry of the annular pore resulting…
The dependence of K Ic on the notch‐root radius has been examined for a notch radius as small as a few micrometers in a dense, fine‐grained, polycrystalline alumina ceramic. The notch radius can be systematically varied by using a semimanual procedure in a special jig which polishes out rather than cuts the specimen.…
Abstract Single‐crystal materials, along with other forms of condensed matter (ceramics, polymers, liquid crystals, etc.) are fundamental to modern technology. The basic research and production of new materials with “tailored” solid‐state physical properties therefore necessitate not only chemical synthesis but also t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDiblock, ABC triblock, and random methacrylic polyampholytes: synthesis by group transfer polymerization and solution behaviorC. S. Patrickios, W. R. Hertler, N. L. Abbott, and T. A. HattonCite this: Macromolecules 1994, 27, 4, 930–937Publication Date (Print):February 1, 199…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, spectroscopy, electrochemistry, spectroelectrochemistry, Langmuir-Blodgett film formation, and molecular orbital calculations of planar binuclear phthalocyaninesNagao Kobayashi, Herman Lam, W. Andrew Nevin, Pavel Janda, Clifford C. Leznoff, Toshiki Koyama, Atsushi…
First‐principles calculations based on density–functional theory and pseudopotentials are used to calculate the energies and relaxed structures of five low‐index surfaces of α‐alumina. Evidence for the reliability of the theoretical methods is provided by calculations of the lattice parameters and internal coordinates…
The residual stresses created in polycrystalline aluminum oxide as a result of its constrained anisotropic thermal contraction are measured with the technique of piezospectroscopy using the fluorescence from trace Cr 3+ impurities. The average residual stresses in the crystallographic a and c directions are determined…
The plastic deformation of sapphire (α‐Al 2 O 3 ) has been studied under hydrostatic confining pressure at temperatures below the ambient pressure brittle‐to‐ductile transition temperature. Samples oriented for prism plane slip (Type I samples) were deformed via dislocation slip at temperatures as low as 200°C. Sample…
The oxidation of unidirectional SiC/C/SiC model composites has been investigated through thermogravimetric analysis, optical/electron microscopy, and electrical measurements. The influence of temperature and carbon interphase thickness on the oxidation of the composites is discussed. The oxidation involves three pheno…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTexaphyrins: Synthesis and ApplicationsJonathan L. Sessler, Gregory Hemmi, Tarak D. Mody, Toshiaki Murai, Anthony Burrell, and Stuart W. YoungCite this: Acc. Chem. Res. 1994, 27, 2, 43–50Publication Date (Print):February 1, 1994Publication History Published online1 May 2002P…
The crystal structure of ternary and binary substrate complexes of the catalytic subunit of cAMP-dependent protein kinase has been refined at 2.2 and 2.25 A resolution, respectively. The ternary complex contains ADP and a 20-residue substrate peptide, whereas the binary complex contains the phosphorylated substrate pe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLangmuir-Blodgett Manipulation of Size-Selected CdSe NanocrystallitesB. O. Dabbousi, C. B. Murray, M. F. Rubner, and M. G. BawendiCite this: Chem. Mater. 1994, 6, 2, 216–219Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published iniss…
Pyridoxal-5'-phosphate-dependent enzymes catalyze manifold reactions in the metabolism of amino acids. A comprehensive comparison of amino acid sequences has shown that most of these enzymes can be assigned to one of three different families of homologous proteins. The sequences of the enzymes of each family were alig…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPrinciple of Maximum Physical HardnessRalph G. PearsonCite this: J. Phys. Chem. 1994, 98, 7, 1989–1992Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published inissue 1 February 1994https://pubs.acs.org/doi/10.1021/j100058a044https://d…
Abstract Sixteen structure types derive from the aristotypic rutile, TiO 2 , structure. Seven of these are based on an ordering of cations: the CoReO 4 , MgUO 4 , AlWO 4 , CuUO 4 , trirutile, CuSb 2 O 6 and FeNb 2 O 6 types; three on an ordering of anions: the InOOH, the manganite and HgFOH types; and six more on vari…