Materials Literature
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Quantitative measurements of the energy dependence of the extinction distance and transmissive power for electron waves in crystals have been carried out photographically and electrically with 100-kV and 300-kV electron microscopes. The observations show that the relativistic correction for the mass of the electron mu…
By firing 3/1 mixtures of rare‐earth oxide (A 2 3+ O 3 ) and niobia or tantala (B 2 6+ O 5 ) at high temperatures, compounds of composition A 3 3+ ‐B 5+ O 7 may be prepared. The crystal structures of such compounds have been examined and two related types have been found. These are identified as a cubic defect fluorit…
Abstract Thermodynamic calculations of Δ G for all possible transformations of metakaolin at the temperature of the first DTA exothermic peak indicates that the most stable transformation is the one that yields mullite rather than γ -alumina. The energy of crystallization of γ -alumina is quite small—36,513 cal per mo…
Abstract The nature of pyridine adsorption by acid- and base-saturated montmorillonite from Otay, California (A.P.I, no. H-24) was studied by infrared adsorption. The spectrum for chemisorbed pyridine was found to be distinctively different from physically adsorbed pyridine; the latter gave a spectrum very similar to…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTParticle Interactions in Aqueous Kaolinite DispersionsA. S. Michaels and J. C. BolgerCite this: Ind. Eng. Chem. Fundamen. 1964, 3, 1, 14–20Publication Date (Print):February 1, 1964Publication History Published online1 May 2002Published inissue 1 February 1964https://pubs.acs…
Properties of a metastable ferroelectric NaNbOa phase are described. This ferroelectric phase was induced by the application of a field greater than 50 kv per cm at a temperature in excess of 100°C. The ferroelectric state was evidenced by a spontaneous polarization of the order of 30 microcoulombs per cm2 and by fair…
The thermal conductivity of titanium carbide, zirconium carbide, and titanium nitride was measured by a variety of techniques in the temperature range 200° to 2000° C. The titanium nitride results are a factor of four higher than the previously published values at 1000°C and show a positive temperature coefficient for…
Abstract Chemical composition, X-ray diffraction and other analytical data of a series of samples of clays that are composed essentially of illite are presented. The physical properties of these samples are given and related to variations in the composition and character of the illites. Data indicate that these illite…
A general mathematical technique for the solution of moiré patterns produced by the overlapping of two figures is presented. The technique is applied to combinations of figures involving parallel lines, radial lines, and concentric circles including those in which the spacing is variable. When an equispaced parallel l…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure Relations in Mixed Metal OxidesLewis Katz and Roland WardCite this: Inorg. Chem. 1964, 3, 2, 205–211Publication Date (Print):February 1, 1964Publication History Published online1 May 2002Published inissue 1 February 1964https://pubs.acs.org/doi/10.1021/ic50012a013h…
The high‐temperature transition monoclinic tetragonal in the rare‐earth tantalates and niobates with the formula AB04 was investigated using a high‐temperature X‐ray diffractometer. The transition was reversible and proceeded by a gradual change in symmetry. The temperature of the first appearance of the tetragonal ph…
The direct and converse piezoelectric effects have been observed in the Achilles tendon of ox and horse, which consists of collagen fibers in which the collagen molecules are highly orientated and crystallized. The matrix of piezoelectric constant is concordant with that derived for and unidirectionally oriented syste…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTParticle to Particle Migration of Hydrogen Atoms on Platinum—Alumina Catalysts from Particle to Neighboring ParticlesS. KhoobiarCite this: J. Phys. Chem. 1964, 68, 2, 411–412Publication Date (Print):February 1, 1964Publication History Published online1 May 2002Published inis…
The stability of the shape of a moving planar liquid-solid interface during the unidirectional freezing of a dilute binary alloy is theoretically investigated by calculating the time dependence of the amplitude of a sinusoidal perturbation of infinitesimal amplitude introduced into the planar shape. The calculation is…
CONTENTS I. Oxidation in gas and liquid phases 13 II. Oxidation in the solid phase 14 III. Oxidation of polypropylene 15 IV. Critical antioxidant concentration 18 V. Initiation of oxidation by antioxidants 20 VI. Theory of synergism 21 VII. Free radicals as stabilisers 23 VIII. Borate stabilisers 25
Abstract Polymers of propylene having highly regular isotactic structure and low molecular weight (down to about 800) were prepared. The melting point, the X‐ray crystallinity, the solubility in some solvents, and the molecular weight of each polymer fraction have been determined. The melting point increases with the…
Vitreous silica compacted by pressure at room temperature expands at a very rapid rate when irradiated with soft x rays or in a reactor, about in the ratio of the ionization doses received. A dose \ensuremath{\sim}\textonehalf{} ${10}^{22}$ eV/${\mathrm{cm}}^{3}$ (i.e., ${10}^{8}$R) of absorbed ionization energy cause…
The paramagnetic resonance spectrum of single crystals of $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ containing chromium grown under conditions favoring the stabilization of ${\mathrm{Cr}}^{4+}$ has been observed. Data were taken at $X$ band at liquid-helium temperatures. A single absorption…
Energy transfer from ${\mathrm{Er}}^{3+}$ to ${\mathrm{Tm}}^{3+}$ and ${\mathrm{Ho}}^{3+}$ ions in crystals has been found to occur. Transfer proceeds from the $^{4}I_{\frac{13}{2}}$ state of ${\mathrm{Er}}^{3+}$ to the $^{3}H_{4}$ and $^{5}I_{7}$ emitted states of ${\mathrm{Tm}}^{3+}$ and ${\mathrm{Ho}}^{3+}$, respec…
These compounds are strongly magnetic. For the heavier rare earths, the gross magnetic moment appears to arise from opposed alignment of the rare earth and the cobalt atoms. If we assume the rare earths to have characteristic localized magnetic moments $\mathrm{Jg}$, the moments on the cobalt atoms are about 1.7 \ensu…