Materials Literature
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Phase relations in the system zirconium‐carbon were established by DTA, X‐ray, and metallo‐graphic methods. Only one phase, a monocar‐bide with the NaCl structure, was found. The low‐carbon phase boundary for the monocarbide contains 38.5 at.7, carbon between 1900’and 3300OC. The carbon‐rich boundary between 2850” and…
Twinned crystals of low cristobalite from Ellora, Hyderabad, India were found to have space group P 4 1 2 1 (or P 4 3 2 1 ) and cell dimensions a = 4.978 and c = 6.94 8 Å. A three-dimensional full-matrix least-squares refinement based upon 110 integrated intensities which were corrected for the effects of twinning, co…
A theoretical analysis, based on the Fuchs-Sondheimer formalism, is given of the conductivity of single-layer, thin metallic films in which the scattering of the conduction electrons is different at each surface. The electron-surface scattering is described by the parameters P and Q which represent the fractions of co…
Dislocation loops have been observed in iron foils irradiated with protons or Fe+ ions of energy 150 kev. Those produced by irradiation with Fe+ ions are shown to lie on {100} planes and to be pure edge in character. They are normally square, with the sides in the corresponding <100> directions, and are formed by the…
Abstract High molecular weight polybenzazoles were prepared by self‐polycondensation of 3,4‐diaminobenzoic acid, 3‐amino‐4‐hydroxybenzoic acid, 4‐amino‐3‐hydroxybenzoic acid, and 4‐amino‐3‐mercaptobenzoic acid, or their inorganic salts in a solution of polyphosphoric acid. These polybenzazoles showed an excellent ther…
Abstract Polyvinyl acetate precipitates from aqueous solution as it is formed. When potassium persulphate is used as initiator the polymer suspension is stable and constitutes the principal locus of reaction. The effect of reaction conditions on the rate of polymerization and on the number of particles formed has been…
Abstract Polybenzoxazoles of high molecular weight were prepared easily by the solution polycondensation of 3,3′‐dihydroxybenzidine dihydrochloride or 3,3′‐diamino‐4,4′‐dihydroxybiphenyl dihydrochloride with both aromatic and aliphatic dicarboxylic acids in polyphosphoric acid. Polybenzothiazoles were prepared from 3,…
Three prominent paramagnetic absorption systems have been detected in single crystals of $\ensuremath{\alpha}$ aluminum oxide (${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$) following reactor irradiation with and without subsequent low-temperature gamma-ray irradiation. The most prominent system has an asymmetric, slightly an…
Photoemission measurements have been made at photon energies between 7.2 and 11.6 eV on single crystals of CdS which had been cleaved in high vacuum at pressures ${10}^{\ensuremath{-}9}$ Torr. Additional measurements have been made from 6 to 21.2 eV using surfaces cleaved and tested in pressures of about ${10}^{\ensur…
The magnetostriction of Tb single crystals has been measured from 4 to 350\ifmmode^\circ\else\textdegree\fi{}K in applied fields up to 30 kOe by strain-gage methods. The temperature dependence of the four magnetostriction constants has been determined under the assumption that the magnetic moment remains in the basal…
The magnetic behavior of very dilute (0.1%) iron impurities in Cu, Ag, Au, V, Nb, Ta, Mo, W, Rh, and Pt has been studied by the M\"ossbauer effect in ${\mathrm{Fe}}^{57}$ for applied fields to 62 kOe and temperatures from 0.5 to 300\ifmmode^\circ\else\textdegree\fi{}K. For V, Nb, and Ta the hyperfine field at the impu…
It has been possible in favorable cases to measure the intensities of the infrared bands of CO adsorbed on different ZnO and supported Cu, CuO, and Pt catalyst surfaces. For weak, reversible adsorption at room temperature, giving rise to the bands in the frequency region 2132–2212 cm−1, a unique correlation between in…
A new empirical intermolecular potential-energy function with two adjustable parameters is developed. When due allowance is made for nonpairwise additivity of intermolecular energy this function is capable of interpreting both the second and third virial coefficients and the solid-state properties of simple substances.
Abstract A dislocation theory of cracks, which takes account of elastic-plastic and other non-linear modes of deformation, is used to discuss the geometrical and physical conditions for unstable fracture. The importance of discontinuous cracking in providing an unstable mode of plane strain, semi-brittle, tensile frac…
A survey is presented of the observed hyperfine fields at nuclei of impurities dissolved in metallic iron. Estimates are made from atomic hfs constants of the contributions to internal fields that might be expected on the basis of conduction-electron polarization. The observed fields in several heavy elements are roug…
The temperature and field dependences of the magnetostriction and thermal expansion of single-crystal dysprosium metal were measured in the paramagnetic, spiral, and ferromagnetic regions. In the paramagnetic temperature range from the N\'eel point to room temperature, the thermal expansion is normal and the six lowes…
Received 24 February 1965DOI:https://doi.org/10.1103/PhysRevLett.14.575©1965 American Physical Society
The complex dielectric constant $\ensuremath{\epsilon}(\ensuremath{\omega})={\ensuremath{\epsilon}}_{1}+i{\ensuremath{\epsilon}}_{2}$ and associated functions are derived by application of the Kramers-Kronig relation to reflectance data for graphite obtained in the energy range to 26 eV. It is possible to divide the o…
Abstract The reaction of lithium aluminum hydride forming mercaptan with disfulfides and mercaptan as well as hydrogen sulfide with polysulfides has been applied in order to characterize the structure of the crosslinks in the case of unaccelerated vulcanization of natural rubber with sulfur. The mercaptans formed were…
The principal structural features of spunbonded products are described, and these structural features are related to physical properties. of the materials and to textile performance.