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Abstract The relative amounts of the α and the γ crystalline forms of nylon 6 obtained from the melt under different crystallization conditions have been studied by an x‐ray diffraction procedure by comparison with a calibration curve obtained from the diffraction of standard samples. The weight fraction of the α form…
Optical constants have been obtained for glassy carbon from 0 to 82 eV by means of reflection measurements. The data have been analyzed by analogy with those for graphite in terms of single electron excitations and of collective oscillations of the π and σ electrons.
Nonisothermal techniques for analyzing initial‐stage sintering are reviewed. It is shown that in principle they permit the determination of all the sintering parameters (rate law, activation energy, and diffusion coefficients) normally obtained from isothermal experiments. Comparison with results from isothermal exper…
Stoichiometric NiAl 2 O 4 , CuAl 2 O 4 , and ZnAl 2 O 4 spinels were prepared and equilibrated at temperatures from 600° to 1400°C. The parameters u and x , denoting the oxygen position and fraction of divalent cations on tetrahedral sites, respectively, were determined from a detailed X‐ray diffraction analysis. In N…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeteropoly and isopoly anions as oxo complexes and their reducibility to mixed-valence bluesMichael T. PopeCite this: Inorg. Chem. 1972, 11, 8, 1973–1974Publication Date (Print):August 1, 1972Publication History Published online1 May 2002Published inissue 1 August 1972https:…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic spectra of the negative ions of some metal phthalocyaninesD. W. Clack and J. R. YandleCite this: Inorg. Chem. 1972, 11, 8, 1738–1742Publication Date (Print):August 1, 1972Publication History Published online1 May 2002Published inissue 1 August 1972https://pubs.acs…
Abstract The reduced Raman spectrum of amorphous Te consists of broad maxima at 90 and 157 cm −1 . The spectrum reflects the vibrational density of states and is interpretable in terms of disordered chains. The highest vibrational energies of the disordered chains are higher than the corresponding energies of the orde…
Abstract Submicrocracks, free radicals, and endgroups of scissioned molecules formed in polyethylene, polypropylene, and polycaprolactam under uniaxial tension have been investigated. Measurements were carried out by small‐angle x‐ray scattering, electron paramagnetic resonance, and infrared spectroscopy. The concentr…
Evidence is presented to demonstrate that although the critical pitting potential is qualitatively related to the resistance of a material to passivity breakdown by pit initiation, it is of questionable value in predicting the corrosion performance of a structure containing crevices. Experiments conducted on a 30Cr-3M…
Azotobacter beijerinckii was grown in ammonia-free glucose-mineral salts media in batch culture and in chemostat cultures limited by the supply of glucose, oxygen or molecular nitrogen. In batch culture poly-beta-hydroxybutyrate was formed towards the end of exponential growth and accumulated to about 74% of the cell…
A trial-and-error method is described for facilitating the indexing of X-ray powder patterns with the help of a computer. It is based on the variation of parameters by dichotomy, i.e. successive division of available phase space. The observational errors are rigorously treated. The program, written in Fortran IV, pres…
From observations of the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking (SCC) in carbon steels, and from the form of potentiodynamic polarization curves and the structural dependence of the corrosive attack, it was predicted that carbonate solutions would also produce in…
M\"ossbauer studies combined with magnetic-susceptibility data on well-characterized LaCo${\mathrm{O}}_{3}$ in the 4.2-1200-K region show that cobalt ions exist predominantly in the low-spin ${\mathrm{Co}}^{\mathrm{III}}$ state at low temperatures which transform partially to high-spin ${\mathrm{Co}}^{3+}$ ions up to…
Abstract Consideration of the relation between the cohesive energy and the surface free energy leads to the inference that dissolved hydrogen reduces the maximum cohesive resistive force of which the iron lattice is capable. This forms the basis of a mechanistic model for the velocity of hydrogen‐induced crack propaga…
The perovskite-like compounds RE(1-X)Pb(5)MnO(3) and RECoO(3), where RE (rare earth) is lanthanum, praseodymium, or neodymium, are active catalysts for the oxidation of carbon monoxide. Crushed single crystals of these compounds compare favorably with commercial platinum catalysts in initial activity and lifetime. The…
Abstract Under certain conditions it is possible to obtain the approximate projected density of a specimen from an electron micrograph, and by taking electron micrographs in different directions a number of different projections of a specimen can be determined. Several methods have been proposed for reconstructing the…
Abstract The compositions of copolymers formed by reacting styrene or α‐methylstyrene (M) with lithium in tetrahydrofuran in the presence of varying amounts of alkyl dibromides (RX 2 ) have been studied. Regular copolymers of structure are formed at 2:1 monomer to dibromide molar stoichiometry, but they become less re…
Electron diffraction patterns having 3500 reflections out to 2 angstromns were obtained from wet microcrystals of catalase. No diffraction was obtained if the water vapor pressure was set below 90 percent of the equilibrium value.
Brief information is presented on the composition and properties of high-strength steels. Questions of their weldability are discussed, modern concepts of the causes and mechanism of cold and hot cracking are set forth and ways of preventing them are suggested. Information about the properties of weld joints, welding…
We have found that the substitutional replacement of Ti for Ta in Ta${\mathrm{S}}_{2}$ stabilizes the octahedral $1T$ phase for $x$ between 0.1 and 0.9. A comparison of the resistivity, magnetic susceptibility, and thermoelectric power shows that at room temperature the properties vary systematically from diamagnetic,…