Materials Literature
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A theory of yielding of glassy polymers by thermally-activated production of local molecular kinks is described. It is possible to obtain the activation free enthalpy of this process by modeling the intermolecular energy barrier as resulting from the stress fields of two equal and opposite closely spaced wedge disclin…
The short-range stresses of the hexagonal screw dislocation boundary, of the straight tilt boundary, and of a zig-zag tilt boundary are computed. These are found to be quite complicated geometrically. They are of comparable magnitude in all three cases but smaller for the straight tilt boundary than for the zig-zag bo…
Tantalum borate (TaBO4) has the zircon structure with unusual coordination for the cations: Ta5+ in eight- and B3+ in four-coordination. The infrared and Raman spectrum is reported and discussed. The symmetrical and asymmetrical BO5−4 valence stretching lies at much lower energy than usually observed in borates. A com…
High-pressure treated titanium and zirconium have been investigated by means of transmission electron microscopy. The specimens consisted mainly of retained ω-phase, while in some regions α-phase platelets were observed. Two crystallographically nonequivalent sets of matrices of correspondence between the α- and ω-pha…
The second-order Raman-scattering spectra of KCl, KBr, KI, RbCl, RbBr, and RbI have been recorded at 300, 90, and 23 K. A symmetry analysis for reducing phonon pairs into irreducible representations has been employed, in conjuction with a knowledge of the one-phonon densities of states derived from neutron-diffraction…
Current noise measurements at high current densities have been applied to the detection of constrictions in thin-film metallization. Potentially open metal films due to scratches, notching, improper step coverage, etc., are easily detected. The noise level, in the absence of such defects, appears to be an indicator of…
Photoemission experiments have been performed on amorphous and crystalline films of Se and Te using photon excitation energies of 1486.6 ($\mathrm{Al}K\ensuremath{\alpha}$), 40.8, and 21.2 eV (He II and He I). From these experiments we have determined the densities of valence states, the binding energies of the core l…
The diffuse scattering of x rays ($\mathrm{Cu}{K}_{\ensuremath{\alpha}l}$) from single crystals of aluminum has been investigated after low-temperature electron irradiation (defect concentrations 3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$ and 5 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-…
The $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}\ensuremath{\approx}0$ phonon spectra of the layer crystals GaSe, GaS, and their solid solutions are presented. All phonon bands in GaSe (${D}_{3h}$ symmetry) and GaS (${D}_{6h}$ symmetry) are assigned and good agreement prevails between experimental results and grou…
Linear-combination-of-atomic-orbitals-molecular-orbitals cluster calculations using the extended H\"uckel theory are carried out for the interstitial carbon in the diamond lattice. The results suggest that the interstitial configuration is not the tetrahedral or hexagonal site, as has been previously assumed, but is i…
A simplified model is introduced to study the temperature dependence of the index of refraction $n$ in the transparent regime of crystals. The dielectric susceptibility is written as a sum of an electronic contribution due to band-to-band transitions and a lattice contribution, viewed as due to a single mode ${\ensure…
We have investigated the phase behavior of 35 N -(p -alkoxybenzylidene)-p -n -alkylaniline compounds, CnH2n + 1O–φ–CHN–φ–CmH2m + 1′ with n values ranging from 1 to 7 and m from 4 to 8 by means of thermal microscopy and differential scanning calorimetry. We report transition energies and entropies in addition to transi…
The ${L}_{2}{M}_{45}{M}_{45}$ and ${L}_{3}{M}_{45}{M}_{45}$ Auger spectra of clean metallic copper and zinc were measured. A theory was developed to predict the Auger energies. The theory employs experimental electron binding energies, which were also measured, two-electron integrals, and Hartree-Fock energies. It acc…
The specific heat and thermal conductivity of amorphous ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$, ${\mathrm{B}}_{2}$${\mathrm{O}}_{3}$, 3Si${\mathrm{O}}_{2}$ \ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{Na}}_{2}$O, CaK${(\mathrm{N}{\mathrm{O}}_{3})}_{3}$, Ge${\mathrm{O}}_{2}$, and GE No. 7031 varnish has been mea…
Fine-grained micas are consistent impurities in Camp-Berteaux (Morocco) and Wyoming montmorillonities. These micas give selected-area electron diffraction spot patterns with triclinic, monoclinic, and hexagonal symmetries similar tO those reported previously for monmorillonites. Camp-Berteaux montmorillonite appears a…
The isotropic-cholesteric and cholesteric-smectic-$A$ phase transitions in cholesteryl oleyl carbonate have been studied for pressures up to 7 kbar. The latter transition possesses a tricritical point at 2.66 kbar and 60.3\ifmmode^\circ\else\textdegree\fi{}C, where the behavior changes from first to second order.
The dynamic mechanical behavior of six samples of styrene–butadiene random copolymers (SBR with 24% styrene) containing different amounts of carbon black and oil extender has been investigated in the temperature range −50° to 80°C. The measurements were carried out using a Fitzgerald apparatus working in the frequency…
Abstract Numerous small mounds are unique features of landscapes that extend from the southern part of Missouri to the coast of Texas. Many hectares of eastern Oklahoma are included in this vast area. The mounds occur in densities of 8 to 16/ha. These mounds were studied with special emphasis on the genesis, morpholog…
Clay fractions of three Andosols and a Latosol occurring in Indonesia, and two Alluvial Soils derived from pyroclastic sediments in the Philippines were examined by means of chemical analyses, X-ray diffraction, differential thermal analysis, thermogravimetry, infrared absorption spectroscopy, and electron microscopy.…
Making use of the radioisotopes of manganese, zinc and antimony, to represent radioactive corrosion products, and a radioisotope of cesium as representative fission product, the transport and deposition of these radioisotopes in a natural circulation sodium loop have been studied over a temperature range from 630°C do…