Materials Literature
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This is the abridged version of a comprehensive volume on the thermal conductivity of the elements. It contains recommended reference values resulting from critical evaluation, analysis, and synthesis of all the available data. It also gives estimated values for those elements for which no thermal conductivity data ar…
A theory is developed to predict the interfacial properties between two immiscible polymers. A self-consistent-field approach is employed to describe the configurational statistics of polymer molecules in the interfacial region. The density profiles and surface tension are calculated, and compare well with experiments…
A 4×4-matrix technique was recently introduced by Teitler and Henvis for finding propagation and reflection by stratified anisotropic media. It is more general than the 2×2-matrix technique developed by Jones and by Abelès and is applicable to problems involving media of low optical symmetry. A little later, we develo…
We have made sound-velocity measurements in the liquid crystal $p$-methoxy-benzylidine, $p\ensuremath{-}n$-butyl-aniline. Near the nematic-isotropic phase transition we observe a dispersion in the sound velocity. Quantitative measurements are presented on the sound-velocity anisotropy in an oriented liquid crystal.
Unlike prior attempts to describe the motion of electronic charge carriers in disordered materials, we suggest that the (holelike) charge carriers may actually be selftrapped, i.e., small polarons. In support of our hypothesis, we discuss our measurements of the electrical conductivity, thermoelectric power, and Hall…
When an electric field is applied perpendicularly to a cholesteric planar texture, periodic perturbations arise. The frequency dependence of the threshold of this instability is reported for nematic-cholesteric mixtures with both positive and negative dielectric anisotropy. In the latter case a "conduction" and a "die…
A molecular field treatment of the B-site spinel was used to determine the ordering temperatures and the asymptotic Curie temperature in terms of the exchange integrals. The theory was developed from a 16-sublattice model and took into account interactions between an atom and its nearest to fourth-nearest neighbors. E…
Resistance changes associated with precipitation in Al–Cu thin films were monitored during power annealing at current densities up to 4×106 A/cm2 and temperatures of ∼178 and 200 °C. The rate of change of resistance decreased as the current increased. It is argued that this decrease is due to the current inhibiting th…
Experimental values of damage rates have been obtained for titanium for electron irradiations in the energy range 0.30-0.50 MeV. A suitable preirradiation annealing treatment has been found, and a value of 19.2\ifmmode\pm\else\textpm\fi{}1.0 eV is determined for the threshold energy of atomic displacement for titanium…
Thin tantalum single-crystal foils with the $〈110〉$ direction normal to the surface have been irradiated with electrons of energies between 1.0 to 3.2 MeV. By varying the orientation of the foil relative to the direction of the beam over a major part of the fundamental triangle, a strong directional effect in the dama…
Inelastic neutron scattering spectra have been obtained at high resolution from a number of aromatic polycrystals, mainly halogenated benzenes, in the range 4 cm−1-1600 cm−1, at room temperature and below. Since the spectra observed reflect only nuclear motion (in contrast to optical spectroscopy), analysis reveals di…
The longitudinal magnetoresistance of a thin metal film has been calculated using Chambers's method. It is assumed that the electron Fermi surface as well as the bulk mean-free path are spherically symmetric. Contrary to previous work based on the assumption of wholly diffuse surface scattering, we consider that scatt…
The low-temperature thermal conductivity $K$ of undoped $n$-type InAs has been measured between 5 and 300 \ifmmode^\circ\else\textdegree\fi{}K, and analyzed on the basis of three different approaches, each including boundary-effect, mass-difference-scattering, and phonon-phonon processes. Various required parameters,…
Mg_6Pd represents the second of the two structure types so far found for complex A_6B compounds of cubic symmetry containing about 400 atoms each per smallest unit cube, arranged according to space group F4{bar]3m. The first type is represented by Na_6Tl. A complete structure determination has been carried out for Mg_…
It is shown that many-body interactions can play a dominant role in nonradiative energy transfer processes between ions in crystals. These interactions formally arise from the Coulomb and exchange interactions between the electrons of the donor ion and two or more acceptor ions. In particular, three-body transfer proc…
CO adsorption on Cu(100) has been found to be completely reversible over the temperature range 77–300°K and pco=10−8−10−4 torr using LEED and work function measurements. The isosteric heat has been determined as a function of coverage, and strong correlations have been found with surface structural changes. An in-regi…
Calculations are presented in connection with a theoretical interpretation of noncubic components in the optical emission spectra of CaF 2 :Dy 3+ system. It is shown that the symmetry of the noncubic centres in the system is tetragonal (C 4v ). Crystal field parameters arrived at are (in cm -1 ): B (2) 0 =298, B (4) 0…
Abstract Polyimides were synthesised from a number of diamines and dianhydrides and their stability determined by thermogravimetric analysis at 400°C in air. Wherever possible high molecular weight films obtained by thermal condensation of the polyamic acid intermediates were studied. If this was not possible, films o…
CeD 2.0 , CeD 2.15 and CeD 2.75 have been examined by neutron diffraction. CeD 2.0 has the ideal fluorite structure. In both CeD 2.15 and CeD 2.75 , interstitial deuterium atoms are displaced about 0.2AA from the position 1/2, 1/2, 1/2 position and there is evidence of a small concentration of normal deuterium vacanci…
In cubic solids the elastic properties cannot affect the sign of the thermal expansion, but in axial solids negative thermal expansion can arise not only from anisotropy in the Gruneisen functions, but also from elastic anisotropy. The origin of negative thermal linear expansion is discussed for arsenic, graphite, sel…