Materials Literature
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Published data on the effect of composition, temperature, crystallization, and thermal history on measured values of the specific heat of glass are reviewed. The Einstein‐Debye relationship between temperature and atomic heat of solids does not apply to vitreous materials. The actual type of function expressing variat…
Detailed investigations on the dielectric and the thermal properties of PbZrO 3 have been made and compared with those of ferroelectric BaTiO 3 . In contrast with barium titanate, volume change at the transition near 220°C has turned out to be expansion, being δV/V=2.7×10 -3 , and a large amount of anomalous specific…
A description is given of edge and screw dislocations in a close-packed cubic lattice, which leads up to an account of the theory of Frank and Read of the origin of slip bands. Consideration is then given to a crystalline grain containing Frank-Read sources; it is shown that one has to expect cross-slip and the format…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpectra of the Metallo-derivatives of α,β,γ,δ-TetraphenylporphineG. D. Dorough, J. R. Miller, and Frank M. HuennekensCite this: J. Am. Chem. Soc. 1951, 73, 9, 4315–4320Publication Date (Print):September 1, 1951Publication History Published online1 May 2002Published inissue 1…
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Hydrogen Positions in Uranium Hydride by Neutron Diffraction1R. E. RundleCite this: J. Am. Chem. Soc. 1951, 73, 9, 4172–4174Publication Date (Print):September 1, 1951Publication History Published online1 May 2002Published inissue 1 September 1951https://pubs.acs.org/doi/…
Electrical conductivity, Hall effect, and Seebeck effect have been measured on two sets of polycrystalline samples of $\ensuremath{\alpha}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ and $\ensuremath{\alpha}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ containing from 0.05 to 1.0 atomic percent titanium ($n$-type impurity). One set of sam…
In this paper, some of the factors which influence the appearance of Lüders bands in mild steel are studied. It is shown that the Lüders band is adequately described by a uniform shear front, spreading over the specimen. In coarse-grained specimens, experiments indicate that this front becomes diffuse; diffuse bands a…
Abstract The infra-red absorption bands associated with the peptide groups in globular proteins, folded synthetic polypeptides and α-fibrous proteins are very similar. The spectra of denatured globular proteins, extended chain synthetic polypeptides and β-fibrous proteins are also very similar. Denatured fibrous insul…
Abstract An apparatus is described in which the thermal conductivity of solids can be determined at any temperature between 2 and 90°K. Several glasses and dielectric crystals have been measured. It had previously been found that at high temperatures the conductivity of glasses is proportional to the specific heat, bu…
Abstract The statistical equilibrium of phonons in the presence of a temperature gradient is investigated, and a general formula for the thermal conductivity of dielectric solids is obtained. This is applied to quartz glass, giving good agreement with values observed by Berman (1951), and to crystals. Comparison betwe…
Abstract L'étude de la cellulose régénérée des composés de gonflement que fournissent avec NH 3 liquide la cellulose native et la cellulose mercerisée conduit à la définition de deux formes correspondantes aux matières de départ: les celluloses IIIα et IIIβ. L'action de l'eau fournit avec le réseau IIIα un réseau élar…
Single crystals of selenium have been grown from the vapour phase and their conductivity and thermo-electric power were measured over a range of temperatures. The Hall effect was determined for one crystal. The conductivity obeys a relatively simple exponential law σ = σ 0 exp (- e E / k T ), with e E = 0.13 eV. and t…
Abstract The elastoviscous behavior of polyisobutylene may be interpreted in terms of a mechanical model consisting of a distribution of Maxwell elements connected in parallel. The structure of this “generalized Maxwell model” is specified by the distribution of relaxation times of the component elements. The relaxati…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Oxidation of Oxalate Ion by Peroxydisulfate1Thomas L. AllenCite this: J. Am. Chem. Soc. 1951, 73, 8, 3589–3593Publication Date (Print):August 1, 1951Publication History Published online1 May 2002Published inissue 1 August 1951https://doi.org/10.1021/ja01152a012RIGHTS & P…
The binary compounds Li 2 O.5Al 2 O 3 and Li 2 O.Al 2 O 3 can be formed easily by reaction of pure materials at 1500°C. The ternary compounds βeucryptite and βT‐spodumene and solid solutions involving these two compounds can be prepared by reaction of Li 2 CO 3 , Al 2 O 3 , and SiO 2 at 1300°C. The thermal expansions…
Magnesium carbonate, basic carbonate, and hydroxide were calcined at temperatures of 300° to 2000°C. for periods ranging from 120 hours at the low temperatures to a few minutes at the higher ones. The resulting magnesium oxides were studied by means of X‐ray powder diffraction and electron and petrographic microscopy.…
Summary The elementary concepts of crystal dislocation theory—in particular the Burgers vector, perfect and imperfect dislocations, sessile dislocations, extended dislocations, twin and twinning dislocations—are defined in a manner independent of particular crystal lattices or models or special orientations of the dis…
Abstract The paper describes how measurements of the spontaneous magnetization of pure specimens of single-crystal close-packed hexagonal and polycrystalline face-centred cubic cobalt have been made over the temperature range -183 to 1121° C. A single crystal of cobalt possessing a close-packed hexagonal structure was…
Neutron scattering and diffraction studies on a series of paramagnetic and antiferromagnetic substances are reported in the present paper. The paramagnetic diffuse scattering predicted by Halpern and Johnson has been studied, resulting in the determination of the magnetic form factor for ${\mathrm{Mn}}^{++}$ ions. Fro…