Materials Literature
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We have observed a clear series of fine structures superposed on the angular dependence of magnetoresistance in the metallic and magnetic-field-induced spin-density-wave phases in the low-dimensional organic superconductor (TMTSF${)}_{2}$${\mathrm{ClO}}_{4}$. They appear at the field angles whose tangent satisfies a f…
We show that director fluctuations in nematics induce long-range interactions between walls, analogous to van der Waals forces, which are attractive with symmetric boundary conditions, but may become repulsive with mixed ones. They affect the swelling of lamellar phases in a nematic solvent. The same phenomenon takes…
We examine equilibrium phase separation in a grafted polymer layer composed of mutually immiscible chains. Under symmetric melt conditions, we predict that there is a transition to a ``rippled'' phase--a density wave in composition running along the surface. This transition is expected for a molecular weight 2.27 time…
The dependence of the flow stress of high-purity α-iron monocrystals on temperature and strain rate, measured by successive tensile deformations at temperatures between 250 and 340 K and correlated stress-relaxation tests, is analysed by means of Seeger's theory of thermally activated kink-pair formation in screw disl…
A microscopic calculation of the second-order Raman-scattering efficiency of silicon, with special emphasis on the effects of uniaxial stress, is presented. Employing diagrammatic perturbation theory, the scattering efficiency is obtained for incident- and scattered-photon energies either on or off resonance. A numeri…
(I) CdSrP 2 O 7 cristallise dans P2 1 /n avec a=5,414, b=8,615, c=12,878 A, β=90,01°, Z=4; affinement jusqu'a R=6,0%. (I) CdBaP 2 O 7 cristallise dans P1 avec a=5,641, b=7,038, c=7,624 A, α=78,55, β=89,83, γ=86,79°, Z=2; affinement jusqu'a R=6,0%. Ces deux composes existent a l'etat solide comme les dichromates, avec…
We study transmission \ensuremath{\Vert}${\mathit{t}}_{\mathit{N}}$\ensuremath{\Vert} and reflection \ensuremath{\Vert}${\mathit{r}}_{\mathit{N}}$\ensuremath{\Vert} of a plane wave (with wave number k>0) through a one-dimensional array of N \ensuremath{\delta}-function potentials with equal strengths v located on t…
(NH 4 ) 3 [H 6 RhMo 6 O 24 ]•6H 2 O cristallise dans P2,1c avec a=11,435, b=11,017, c=11,789 A, β=100,02, Z=2; affinement jusqu'a R=0,042. Le polyanion [H 6 RhMo 6 O 24 ] 3− , de symetrie D 3d , est de meme structure que [H 6 Cr II Mo 6 O 24 ] 3− . L'octaedre RhO 6 , situe sur un centre d'inversion, est de forme rhomb…
Reflection-absorption infrared spectroscopy (RAIRS) in the spectral region 1700--280 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ used to identify and characterize three forms of oxygen adsorbed on a polycrystalline silver ribbon. The high resolution of RAIRS allows us to interpret the spectra resulting from adsorption…
The photoionization efficiency spectra of nickel clusters containing adsorbed ammonia have been recorded near threshold. Ionization potentials (IPs) have been assigned for 97 selected Nin(NH3)m species, with n up to 56 atoms. We observe that nickel cluster IPs decrease upon ammonia adsorption, with the magnitude of th…
The absorption of H and D into a palladium sphere of precise radius and density is examined experimentally with use of pressure-volume-temperature measurements and control techniques to achieve the stepwise boundary condition and constant pressure assumed in the common solutions to Fick's second law. Measurements were…
Photoelectron diffraction and Auger-electron diffraction studies to date have involved the study of the elastically scattered or ``no-loss'' features in spectra. In this work, we consider the diffraction patterns associated with inelastically scattered electrons in plasmon satellites. Although very similar in most pea…
Electro-optic properties of thin polymeric films can be studied by incorporating the films into the spacer layers of transmission-mode Fabry–Pérot devices formed using metal mirrors. The metal mirrors, which also serve as electrodes, are used for the application of an electric field for poling the polymeric material a…
Sound velocity, υ s , has been measured to examine the thermodynamics of structural transitions in the liquid Se-Te system. The isothermal compressibility, κ T , deduced from υ s together with the thermal expansion coefficient, α P , the constant pressure specific heat, C P , and the density shows a broad maximum when…
The detailed quantitative speciation of phosphorus and selenium microstructures in phosphorus-selenium glasses is derived from combined $^{31}\mathrm{P}$ spin-echo and magic-angle-spinning NMR experiments. The results illustrate that the structure of these glasses differs from the chemically ordered or clustered struc…
Abstract Differential scanning calorimetry (DSC) and in situ small‐angle x‐ray scattering (SAXS) indicate that in an α ω‐methoxy‐poly(ethylene oxide) (MPEO) fraction (MW 3000) a transient nonintegral folding (NIF) crystal initially forms during crystallization throughout a wide range of crystallization temperatures. S…
Evidence for interaction between the N-N pair and interstitial O in N-doped Czochralski silicon has been presented by studying the annealing behavior of the corresponding IR absorption bands.
Diamond powders with grain diameters up to 0.3 μm were obtained by CO2 -laser-induced decomposition of C2H4 at low pressures and temperatures. C2H4 or mixtures of C2H4, H2, and SiH4 were irradiated in a gas-flow reactor with the 10P14 line (10.532 μm) of a grating-tunable CO2 laser with 50-W cw output power. Solid pro…
Selectively deuterated glycerol has been subjected to 2 H-NMR spin-lattice relaxation and quasi-elastic neutron scattering experiments. The measurements yield relaxation rates and a non-Gaussian Q -dependence of the Debye-Waller factor which are different for the two hydrogen sites. The data analysis shows that below…
Dense fluids of biaxial hard convex bodies exhibit a phase transition from an isotropic to a nematic (I–N) liquid–crystalline state. In the Onsager theory, the I–N transition is attributed to the tendency of pairs of molecules to minimize their excluded volume (or second virial coefficient, B2 ). In the present work,…