Materials Literature
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The mechanisms by which porphyrins form metal complexes in nature are of interest because of the importance of both the iron complexes, the active sites of hemoproteins, and the magnesium complexes, the chlorophylls. Currently there is interest in using chelated radioactive metal isotopes as diagnostic imaging and the…
The coexistence of spin-density waves and superconductivity has been theoretically analyzed in a two-band model, a case for which the commonly used descriptions for the ternary rare-earth compounds and highly anisotropic organic solids are unapplicable. The phase diagram at T=0, the temperature dependence of the order…
Metal–ligand association constants of 1:1 binary (ML) and 1:1:1 ternary (MAL) complexes of the type [Formula: see text] (where M = La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , or Sm 3+ ; A = primary ligand = EDTA; L = secondary ligand = O—O, O—N, O—S donor aliphatic or aromatic ligand) have been determined potentiometrically by th…
The actual atomic concentration of Mg segregated to the basal plane of MgO‐doped single‐crystal alumina surfaces is calculated using an Auger electron spectroscopy quantification method which takes the backscattering factors and Auger electron escape depth into account. The results suggest that Mg segregates as effect…
Abstract Unique empirical relations are found to exist between the extension ratio at break λ b and the crosslink density ν λ b ∝ ν −0.75 in the absence of gross strain induced crystallization, and λ b ∝ ν −0.2 in the presence of gross strain-induced crystallization. With black-filled elastomers, the modulus at 100% s…
A model is presented that examines the mixing of ceramic powders with preceramic polymer binders that are converted to ceramic material on pyrolysis. Such polymer/powder systems, which have applications in the compaction of both SiC and Si 3 N 4 powders, can be effective in increasing the green density of die‐pressed…
A new bromide spinel has been found in the system. The orthorhombic cell dimensions are , , and at room temperature. The electrical conductivities of the new bromide spinel and the related spinel have been measured. and have been found to have high ionic conductivities of and at 400°C, respectively. High temperature x…
The trapping of radiation-induced self-interstitials by solute atoms in iron dilute alloys has been investigated by means of resistivity measurements. The present paper deals with the three systems FeNi, FeCo and FeMn. Specimens containing 50 to 400 at. p.p.m. of solute has been electron irradiated together with pure…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEvidence for a metallo ketone complex in the reactions of rhodium octaethylporphyrin dimer with carbon monoxide: solution equilibria and spectroscopic studiesBradford B. Wayland, Bruce A. Woods, and Virginia L. CoffinCite this: Organometallics 1986, 5, 5, 1059–1062Publicatio…
SUMMARY Interface microstructures between rhombohedral Sm 2 Co 17 and hexagonal SmCo 5 phases in a sintered permanent magnet of Sm(Co 0.675 Fe 0.175Ni 0.05 Cu 0.1 ) 7 have been investigated by edge‐on observations with the many‐beam imaging technique. In the specimen annealed at 800°C for 4 h which shows a maximum mag…
A new theory for the transition from columnar to equiaxed crystals has been developed. It is proposed that free crystals are formed in the liquid ahead of the growing front and that these crystals grow in the liquid as a result of natural convection. When the free crystals are sufficiently large or sufficiently numero…
Measurements of the emanation coefficients of 222Rn from coal ash were performed. Samples of coal ash from a stoker-fired furnace were mechanically sized into four categories. The mean 226Ra concentration of these categories ranged from 11.82-16.77 dpm g-1 and increased as a function of decreasing particle size. The m…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure and infrared and Raman spectra of potassium vanadium sulfate (KV(SO4)2)Rasmus Fehrmann, Bernt Krebs, G. N. Papatheodorou, Rolf W. Berg, and Niels J. BjerrumCite this: Inorg. Chem. 1986, 25, 10, 1571–1577Publication Date (Print):May 1, 1986Publication Histor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron microscopy and magnetic studies of the interaction between nickel and silica: suggestion for possible anchoring sitesL. Bonneviot, M. Che, D. Olivier, G. A. Martin, and E. FreundCite this: J. Phys. Chem. 1986, 90, 10, 2112–2117Publication Date (Print):May 1, 1986Pub…
Projected fatigue life analyses are performed to estimate the endurance of a cardiac valve prosthesis under physiological environmental and mechanical conditions. The analyses are conducted using both the classical stress-strain/life and the fracture mechanics-based damage-tolerant approaches, and provide estimates of…
Three models of the weakening of quartz by small amounts of water are described and analysed. Attention is confined to the glide of dislocations caused by a double-kink nucleation process. The structure of a double kink on a basal 60° dislocation is described and its formation energy estimated using a short-range inte…
A light-harvesting fucoxanthin-chlorophyll a/c-protein complex has been isolated from the diatom Phaeodactylum tricornutum by detergent extraction of thylakoid membranes coupled with sucrose density gradient centrifugation. The isolated complex was devoid of photochemical activity and displayed spectral characteristic…
Abstract The soils on the Mall in Washington, DC have formed in about 6 m of miscellaneous fill deposited in repeated applications to the site during filling operations. Some limited pedogenesis has occurred; cambic, or cambic‐like B horizons were recognized in 26% of the profiles examined. Buried A horizons were foun…
The pseudopotential method is used to examine the structural stability of high-pressure orthorhombic, rhombohedral (A-7), and simple cubic (sc) phases of black phosphorus. The calculated ground-state properties are in good agreement with the measured values for each phase. A total-energy study gives the orthorhombic p…
Abstract A convenient method for the synthesis of poly(benzoxazole)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aromatic dicarboxylic acids containing phenyl either structure with 3,3′‐dihydroxybenzidine dihydrochloride using phosphorus pentoxide/me…