Materials Literature
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Abstract We extend a method devised by Lord Rayleigh to enable the calculation of the transport properties of circular cylinders in square and hexagonal arrays. The theory is confirmed by measurements on arrays of perfectly conducting cylinders, and also is compared with asymptotic formulae due to Keller (1963) and O’…
The kinematic inconsistencies for the Hartree-Fock magnon energy renormalisation in a ferromagnet with uniaxial anisotropy are shown to be eliminated by taking into account additional anisotropy terms present in the second-order self-energy.
A programme of elastic neutron-diffraction experiments has been undertaken to derive (and compare) atomic distribution functions, with high spatial resolution, for the antiferroelectric perovskites SiTiO 3 , KMnF 3 , RbCaF 3 and CsPbCl 3 in their cubic phase. The study of cubic CsPbCl 3 is presented. Data were collect…
The energy spectrum and wave functions for a particle in periodic potentials with incommensurate periods are obtained analytically and reduced to specific phase trajectories. The spectrum is of the devil's-stairs type. States may be extended and localized, separated by mobility edges. These results are applicable to i…
Abstract Brillouin scattering spectra, with a single mode argon-ion laser and triple-pass Fabry-Perot interferometer, have been measured for natural biological fibres and for films of synthetic polypeptides. For wet unstretched rat tail collagen, with the scattering vector parallel and perpendicular to the fibre axis,…
It is shown that the C 1s core-electron line shape of graphite in photoemission is determined by an excitonic state near the Fermi energy in the hole-state density of states.Received 14 September 1979DOI:https://doi.org/10.1103/PhysRevLett.43.1896©1979 American Physical Society
Anomalous behaviors are found in thermodynamic properties of FeNi (f.c.c.) alloys measured by the solid state electrolyte cell method at 900 to 1300 K. The alloys containing 20 to 50 at% Ni seem to have a tendency to split into two f.c.c. phases even at high temperatures. This is consistent with the fact that the com…
Silicon crystals containing up to 1015 cm−3 of „oxygen donors”︁ are investigated by electrical and infrared spectroscopic measurements. The results obtained can be understood phenomenologically by the occurrence of several species of doubly charged donors, whose excited states can be fairly well described by the effec…
H2Pt(OH) 6, monoclinic, C2/c, a = 8.459 (5), b = 7.184 (5), c = 7.429 (4) A,/~ = 93.71 (2) ° at 297 K, Z -4, D,n = 4.17, D c = 4.408 Mg m -3. The structure is a slight distortion of the K2PtCI 6 type, with nearly regular Pt(OH) 6 octahedra forming an approximately face-centred cubic array. Short O . . . O distances be…
Earlier results had indicated, under some conditions, a discrepancy between the observed spectral distribution of phonons produced by the heat-pulse method and the distribution predicted by the acoustic-mismatch model. Through additional measurements of the film temperature we show that the discrepancy can be resolved…
The structure of orthorhombic hexachloroethane has been refined at 294 and 140 K. At room temperature 983 symmetry-independent reflections were measured on a four-circle neutron diffractometer. The final R(F) was 0..066 including an isotropic extinction parameter. At 140 K 793 symmetry-independent reflections refined…
A many-body system sliding at constant center-of-mass velocity relative to an external periodic potential (e.g., due to the channels in which the ions move in an ionic conductor) is studied as a possible model for dynamical friction and as a model for electrical conduction in superionic conductors and systems containi…
Wakabayashi et al. fitted a force-constant model to the purely transverse phonon dispersion curves from their neutron scattering measurements on $1T$-Ti${\mathrm{Se}}_{2}$. Their model is extended here to fit the remaining phonon branches observed by them and the LA branch in the $c$ direction studied by Stirling et a…
We have measured the magnetic susceptibility of alkali-graphite intercalation compounds for $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ parallel to the hexagonal $\stackrel{\ensuremath{\rightarrow}}{\mathrm{c}}$ axis (${\ensuremath{\chi}}^{c}$) and for $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}\ensuremath{…
In this paper the first magnetic-susceptibility results for a fluid metal are reported, which cover a wide range of expansion between the normal melting point and conditions near the critical point. Measurements have been performed for fluid Cs at saturation conditions up to 1680\ifmmode^\circ\else\textdegree\fi{}C an…
We perform an analysis of the \ensuremath{\sim} 1500 ${\mathrm{cm}}^{\ensuremath{-}1}$ Breit-Wigner interference feature in the Raman spectra of stage-1 (${\mathrm{C}}_{8}X$, $X=\mathrm{K},\phantom{\rule{0ex}{0ex}}\mathrm{R}\mathrm{b},\phantom{\rule{0ex}{0ex}}\mathrm{C}\mathrm{s}$) graphite-alkali-metal intercalation…
A method is described for quantitative analysis of low-energy-electron diffraction (LEED) intensity-energy spectra by comparison of experimental spectra with spectra calculated using a dynamic theory of LEED. The method involves a minimization of the variance of the fit between experimental and calculated spectra as a…
Abstract Dynamic mechanical measurements have been made on a 4,4′‐diaminodiphenyl sulfone‐cured tetraglycidyl 4,4′‐diaminodiphenylmethane epoxy (TGDDM‐DDS). There are basically three transitions on the mechanical spectra that have been identified, and the effects of moisture uptake and amount of DDS on these transitio…
A theory of the magnetoresistance of disordered carbons is presented and applied to experimental results on carbon fibers and glassy carbon. The important features of the model include (a) a two-dimensional band structure and density of states, (b) a shallow acceptor level due to defects, (c) collision-broadened Landa…
We have examined the (001) and (110) faces of Ti${\mathrm{O}}_{2}$ (rutile) using ultraviolet photoelectron spectroscopy (UPS), low-energy-electron diffraction (LEED), and Auger electron spectroscopy (AES). We found that the (001) surface is unstable and reconstructs or facets when annealed while the (110) surface is…