Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultinuclear magnetic resonance spectroscopy of spin-admixed S = 5/2, 3/2 iron(III) porphyrinsArden D. Boersma and Harold M. GoffCite this: Inorg. Chem. 1982, 21, 2, 581–586Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published iniss…
The crystal structure of a reverse pleochroic muscovite containing both Fe3+ and Mn3* has been determined by standard single-crystal X-ray methods. The mica has a 2Mr polytype, space grou-p C 2lc. Cellconstants are a :5.1988A esd 0.0021, b = 9.02664 esd 0.0019, c : 20.1058A esd 0.Cf.44, I = 95JE2' esd 0.039, V = 938.7…
The stability criteria for pitting dissolution of metals are examined on the basis of recent results. Pitting dissolution is stable if the local ion concentration buildup at pit sites exceeds a certain critical value, which for pits at noble potentials appears to correspond to the lowest ion concentration required for…
Calculations of diffraction line profiles and Scherrer constants for crystallites whose external shape has cubic symmetry are extended to crystallites of cylindrical shape. The analysis includes the limiting cases of acicular crystals and disks and, to a reasonable degree of approximation in many cases, to hexagonal p…
Abstract The reactivity and related properties of oxygen both in the bulk and on the surface has been investigated for perovskite-type mixed oxides (La1−xSrxCoO3), in regard to the effects of Sr2+-substitution and calcination temperature. The reducibility and the readiness of oxygen desorption increased with the Sr2+…
The Raman spectra of YFe${\mathrm{O}}_{3}$, SmFe${\mathrm{O}}_{3}$, DyFe${\mathrm{O}}_{3}$, HoFe${\mathrm{O}}_{3}$, and ErFe${\mathrm{O}}_{3}$ have been measured as a function of temperature from 8 to 650 K. For all the materials, the spectra show two features in the 5 to 20 ${\mathrm{cm}}^{\ensuremath{-}1}$ range. Fr…
The article begins with an account of prewar German work, particularly that of von Ardenne, who established the theoretical basis of a scanning electron microscope and constructed an instrument which was primarily intended to overcome chromatic aberration when relatively thick specimens were examined by transmission.…
Examination of the three-dimensional structure of periphyton communities through time indicated that their microsuccession is analogous to higher plant succession. The development of attached diatom communities in two reservoirs was studied using artificial substrates, and the morphology of dominant organisms, pattern…
The fluorescence of molecules on silver-island films exhibits nonexponential decay and is several orders of magnitude more rapid than on a silica surface, while the total emission intensity is slightly increased. This behavior results from the electromagnetic coupling between the fluorescing molecules and the plasmon…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCalcium carbonate crystallization kineticsLarry D. Swinney, John D. Stevens, and Robert W. PetersCite this: Ind. Eng. Chem. Fundamen. 1982, 21, 1, 31–36Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published inissue 1 February 1982htt…
The multiple-trapping model is used in order to analyse the propagation and broadening of a carrier packet. The traps are considered to be distributed over rather a wide energy region in the gap. We assume that at the initial moment traps are empty and all the carriers occupy mobile states. Under these conditions the…
Several peptides containing intermolecular crosslinks were isolated from tryptic digests of the insoluble matrix of human leiomyoma and calf aorta. From leiomyoma type III collagen, two crosslinked peptides were isolated. The peptide [T N (III)] 2 , is a dimer which contains the 73 amino‐terminal residues of two, zero…
Abstract The effect of initiation of ϵ‐caprolactone polymerization with mono‐ and polyfunctional alcohols was investigated. The resulting linear and starshaped polymers were characterized by measurement of the molecular weight and molecular weight distribution. The polymerizations were characterized by (1) rapid initi…
Abstract Nonstoichiometry and point defect structure of magnetite have been studied experimentally by thermogravimetry covering the stability range of magnetite between 900 and 1400 °C. A cation deficit is observed at high and a cation excess at low oxygen activities corresponding to cation vacancies and iron intersti…
Multiple electron scattering between weak beams has been used as the basis for a simple method to determine the absolute polarity of some non-centrosymmetric crystals. For crystals with the sphalerite structure many orientations have been found in which small departures from centrosymmetry produce large effects on the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface spectroscopic characterization of cobalt-alumina catalystsRoland L. Chin and David M. HerculesCite this: J. Phys. Chem. 1982, 86, 3, 360–367Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published inissue 1 February 1982https:/…
Abstract The fundamental properties of 12-heteropolyacids of Mo and W, such as the structure, the surface area, the acidity, and the reduction-oxidation mechanism, have been studied in their solid state in relation to heterogeneous catalysis. The primary structure (heteropolyanion) was rather stable, but the secondary…
We have developed a line of Chinese hamster ovary cells with a 500-fold increase in 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the membrane-bound enzyme that controls cholesterol synthesis. This line, designated (UT-1, was obtained by stepwise adaptation of cells to growth in increasing concentrations of compact…
The infrared transmission and reflection spectra of Co II Co III 2 O 4 , CoAl 2 O 4 , ZnFe 2 O 4 and MnFe 2 O 4 and the single crystal Raman spectra of Co II Co III 2 O 4 and CoAl 2 O 4 have been measured. The frequencies of the transverse (TO) and longitudinal (LO) modes of the infrared active species have been obtai…
A classical result due to Daniels is that the strength of a bundle of parallel fibres is asymptotically normally distributed. Extensions of this result are obtained and applied to a series-parallel model consisting of a long chain of bundles arranged in series. This model is of importance in studying the reliability o…