Materials Literature
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SUMMARY Results are reported concerning the use of an energy dispersive X‐ray detector to carry out the analysis of thin foils in the electron microscope. The combination of a thin specimen and the extreme stability of the energy dispersive X‐ray detector enables the experimental determination of a calibration curve o…
The d1 layer metals TaS2, TaSe2, NbSe2, in all their various polytypic modifications, acquire, below some appropriate temperature, phase conditions that their electromagnetic properties have previously revealed as ‘anomalous’. Our present electron-microscope studies indicate that this anomalous behaviour usually inclu…
The products from nonflaming combustion of wood and a trimethylol-propane-based rigid-urethane foam that was not fire-retarded produced elevated carboxyhemoglobin levels but no abnormal neurological effects. However, when this type of foam contained a reactive phosphate fire retardant, the combustion products caused g…
This review is concerned with the structure, electrical, and optical properties of mixed-valence platinum complexes of the K2 Pt(CN)1, Br0.303H2O type and of TTF-TCNQ salts. Special attention is paid to the experimental results on the anisotropy of electron motion in these quasi-one-dimensional crystals. The theory of…
Abstract This work examines the effect that appreciable molecular extension has on the crystallization of long chain molecules. Elementary theoretical considerations presented indicate that to achieve high molecular extensions in solution a longitudinal velocity gradient of strain rate about 103s-1 is required. A meth…
Abstract The nature of slow crack and craze propagation in polymers and crack propagation in inorganic glass has been considered in terms of time dependent processes. By using a fracture mechanics analysis together with time dependent material parameters, equations have been derived to describe crack and craze propaga…
The Laplace–Young equation is solved for axisymmetric menisci, analytically in terms of elliptic integrals for all possible types of pendular rings and liquid bridges when the effect of gravity is negligible, numerically for selected other cases in order to assess gravity's effect. Meniscus shapes, mean curvatures, ar…
The semiconductor-metal transition in VO 2 has been investigated by means of XPS measurements. The band gap in the semiconducting region is found to be temperature-dependent with a room temperature value of E g =0.3 eV, in agreement with resistivity measurements. The core lines, which are asymmetric below T nu broaden…
We report partial densities of states of overlapping bandlike $p$ states and localized $d$ states in several insulating transition-metal oxides which have been determined from frequency-dependent photoemission spectra taken in the range 5-90 eV. We observe that $p$-band features become weak relative to $d$-state and s…
Some defects of the host lattice of crystals of the T3Al5O12 series (where T is Tb, Dy, Y, Ho, Er, Tu, Yb, Lu) doped with rare-earth ions (TR3+), are investigated by means of an analysis of the inhomogeneous splitting of the spectral lines of the TR3+ impurity ions. The connection of the concentration of some defect t…
A study of Ni3Mo by electron microscopy and electron diffraction reveals the presence of a new metastable intermediate phase during the early stages of ordering. This phase having the DO22 structure is only observed under well specified experimental conditions; it is generated immediately from the short range ordered…
Optical properties of single crystals of lead molybdate and lead tungstate (scheelite structure) have been investigated in order to identify the nature of the luminescent centres. Absorption, emission, and excitation spectra at different temperatures (1.5 to 300 K) and photoconductivity and quantum efficiency measurem…
Very low transmission loss fiber optical waveguides have been developed during the past two years which have pure fused silica cores surrounded by borosilicate glass claddings. A recent study of the binary borosilicate glass system revealed that the low refractive index values which can be achieved with this glass and…
A new technique is presented for evaluating the electron Green function G k (t) in an insulating electron–phonon system. The technique is particularly suitable for those electron–phonon interactions in which the long wavelength phonons are of prime importance such as the polaron and piezoelectric interactions.An exact…
Calculations of the frequency and temperature dependence of infrared multiphonon absorption for the alkali halides and alkaline-earth flourides are compared with previously published data and some new results. The temperature dependence of the infrared absorption of pure crystals of NaF, NaCl, and KCl at 10.6 \ensurem…
The reflectivity and ${\ensuremath{\epsilon}}_{2}$ spectra of the fcc metals Rh, Pd, Ir, and Pt are reviewed and discussed between about 0.1 and 30 eV. Structures in ${\ensuremath{\epsilon}}_{2}$ are interpreted in terms of recent band calculations. Calculations of the joint density of states and ${\ensuremath{\epsilo…
Solutions have been obtained to equations which described the interface between two immiscible polymers and are more general than the equations first introduced by Helfand and Tagami. Gaussian random−walk statistics are assumed for the macromolecules. As a consequence of the present work, limitations of the earlier th…
Resistivity and Hall effect measurements have been made on ${\mathrm{Sm}}_{1\ensuremath{-}x}{\mathrm{Y}}_{x}\mathrm{S}$ alloys which exhibit black to gold phase transitions as a function of temperature and composition, similar to SmS under pressure. The results indicate that in the gold phase there is a virtual bound…
The structure factor of amorphous solid D(2)O deposited from the vapor at 10 degrees K has been obtained by measuring the neutron diffraction spectrum in the wave vector transfer from 0.8 to 12.3 reciprocal angstroms. The results indicate that the phase investigated is amorphous and has a liquiid-like structure factor…
We present numerical calculations based on a tight-binding model for the organic conductor tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ). The model consists of anisotropic planar TTF and TCNQ bands coupled together by an interplanar transfer integral, which produces a nearly zero-bandgap semiconductor. The ca…