Materials Literature
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Abstract Specimens of poly(vinylidene fluoride), crystal form II, annealed at different temperatures between 130 and 180°C were characterized by specific volume measurements, differential scanning calorimetry (DSC), and electron micróscopy. The degree of crystallinity calculated from the specific volume changed only b…
Elastic- and inelastic-scattering cross sections for low-energy electrons in Hg have been obtained through comparison of experimental and calculated transport data. Electron-electron interactions and superelastic collisions are incorporated into the numerical solution for the electron-energy distribution. The electron…
An outline is given of the effects of the various processes occurring at a structural phase transformation on the quantities measured in an ultrasonic experiment: sound velocity and attenuation. Various theoretical approaches are discussed as well as experimental results.
The advantages of a systematic application of the method of virtual power are exemplified by the study of continuous media with microstructure. Results on micromorphic media of order one are easily found and the equations of motion for the general micromorphic medium are established for the first time. Various interes…
Data on the preparation, structure, and various properties of the double tungstates and molybdates (EO4) of the alkali (M) and rare earth (R) metals with the composition RM(EO4)2 have been summarised and systematised. The regular features of the change in the symmetry, polymorphism, and nature of the fusion with chang…
Intrinsic photoemission and photoconduction of polyethylene in the photon energy range 7<E<14 eV have been experimentally investigated. Both phenomena are parabolic in E with the same threshold energy E G =8.8 eV. The main features of a model that accounts for the observations are: (a) E G is the intrinsic electron-ho…
The temperature dependence of the electrical conductivity and Seebeck coefficient for the polymer chain system ${(\mathrm{SN})}_{x}$ has been measured along the chain axis from 4.2 to 300\ifmmode^\circ\else\textdegree\fi{}K. The data show the system to be metallic over the entire temperature range studied, with a smal…
The growth of color centers and the accompanying changes in the mechanical properties (flow stress, Vicker's microhardness and dislocation mobilities) of CaF2 single crystals due to γ-ray irradiation has been studied in the dosage range of 104 to 5 × 108 R at room temperature. Of the four absorption band spectra with…
The mobilities of edge and screw dislocations in Fe-3% Si weremeasured directly by using an etch-pitting method in the temperature range of 298 to 198 °K. It was also examined whether or not there is asymmetry in the mobility of screw dislocations with respect to a reversal ofthe sign of the applied shear stress. From…
perimental value of ZnO in Table IV should be h;~= -l. 19(not -0. 19as is misprinted).In Fig. 4 the negative 4,~(expt) axis should, of course, read -l. 2 (not -0.2).Reference 1 of this paper (as well as Ref. 3 of the previous paper) should
The polarized optical absorption spectrum of the first exciton band (the first progression member of 1A1 exciton band) of crystalline phenanthrene has been measured in the temperature range 81 to 293 °K. The exciton-phonon interaction is discussed using Toyozawa's theory. The lower energy tail of the first exciton abs…
Detailed measurements of the temperature dependence of the EPR spectrum and Hall coefficient of niobium-doped rutile have been made. At 4.2 \ifmmode^\circ\else\textdegree\fi{}K and 34 GHz, the EPR spectrum consists of a set of well-resolved hyperfine lines which coalesce and then shift with increasing temperature. Com…
Torsional stress pulses of several microseconds duration were applied at 4.2 \ifmmode^\circ\else\textdegree\fi{}K to cylindrical single crystals of copper containing freshly introduced dislocations. Dislocation displacements were measured by means of a double-etch technique, and subsequently the dislocation damping co…
New measurements of electrical conductivity and Hall constants have been performed on single crystals of ${\mathrm{Na}}_{x}\mathrm{W}{\mathrm{O}}_{3}$ for $0.22<x<0.63$ and temperatures from 1.2 to 300 K. The conductivity varies with $x$ according to the relation, $\ensuremath{\sigma}\ensuremath{\propto}{(x\ensu…
The two theoretical approaches to extended x-ray-absorption fine structure, based on either "long-range order" or "short-range order" are critically examined within a muffin-tin-scatterer model. It is argued that the two apparently dissimilar theories will in practice yield essentially the same results. The argument i…
Vibrational excitation of ${\mathrm{O}}_{2}$ by electrons in the energy range 4-15 eV is studied with a crossed-beam double electrostatic analyzer. The differential vibrational cross sections for $v=1\ensuremath{-}4$ at 25\ifmmode^\circ\else\textdegree\fi{} show a bell-shaped energy dependence peaked near 9.5 eV. The…
The use of VO2 films for direct-bit optical storage with near-infrared lasers is demonstrated. The VO2 response is fast (&lt; 10 ns), and large read signals are obtained with unpolarized light. A writing threshold of 0.03 nJ/μm2 is observed.
Large reversible thermochromic changes in pure and transition-metal-doped SrTi${\mathrm{O}}_{3}$ were observed which depend markedly on impurity concentration, anealing temperature, and especially on the rapidity of the quench. The material also changes its electrical properties from insulator to semimetallic, and for…
An electronic structure, in terms of molecular orbitals, is suggested for the layered compound Ti${\mathrm{S}}_{2}$. This structure is based on the combined $\mathrm{Ti}{L}_{\mathrm{III}}$, $\mathrm{Ti}K$, $\mathrm{S}{L}_{\mathrm{II},\mathrm{III}}$, and $\mathrm{S}K$ x-ray-emission and -absorption band spectra. The x-…
Orthorhombic CuFe 2 S 3 is weakly ferromagnetic. The magnetic susceptibilities of single-crystal and polycrystalline specimens have been determined at temperatures between 78 and 500 °K. A model is presented to explain the weak ferromagnetism.