Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDependence of the glass transition temperature on heating and cooling rateCornelius T. Moynihan, Allan J. Easteal, James Wilder, and Joseph TuckerCite this: J. Phys. Chem. 1974, 78, 26, 2673–2677Publication Date (Print):December 19, 1974Publication History Published online16…
The equations of motion of a 180° domain wall in an infinite uniaxially anisotropic medium which is exposed to an instantaneously applied uniform dc magnetic field H0 have been integrated numerically. Below the critical field Hc =2παM0 (α is the Gilbert loss parameter and M0 the saturation magnetization), where a stea…
The mechanical behaviour of carbon-fibre-composite specimens of fibre volume fractions from 30 to 60% and various fibre orientation has been investigated experimentally for compression loading up to 200 MN m −2 and duration approximately 30 μs. A split Hopkinson pressure bar technique has been employed with an optical…
The magnitudes and signs of isotropic and anisotropic hyperfine (HF) fields and the magnitude of the electric field gradient (EFG) at the nuclei of diamagnetic Ga3+ ions in tetrahedral sites of lithium ferrite gallates Li0.5Fe2.5−xGaxO4 (0.01 ≦ x ≦ 0.65) have been determined from the analysis of low temperature Ga69.7…
The dielectric relaxation of CsBr and CsI containing impurities such as Pb++ and Cd++ has been investigated, using the dielectric loss method. The activation energy E, required for the migration of a cation vacancy, obtained from de conductivity measurements is in good agreement with that resulting from the dielectric…
The ESR study of V4+ in amorphous V2O5 shows that this ion is in a site having a strong axial anisotropy. The parameters of the spin Hamiltonian describing the spectra are g∥ = 1.926, A = 190 × 10−4 cm−1, g⟂ = 1.984, and B = 73×10−4 cm−1. A comparison with the ESR spectra of V4+ in V2O5 single crystals shows that shor…
The Raman spectra of both the $\ensuremath{\alpha}$ and $\ensuremath{\beta}$ phases of Na${\mathrm{N}}_{3}$ have been obtained and interpreted. The Raman-active ${E}_{g}$ mode of the $\ensuremath{\beta}$ phase splits into ${A}_{g}$ and ${B}_{g}$ modes as Na${\mathrm{N}}_{3}$ undergoes a phase transition at approximate…
A novel electrically reversible storage effect in doped nematic liquid crystals is described. The ``off state'' is homeotropic nematic and the ``on state'' a single layer of densely packed spherulites. Both states are stable in time. The effect was observed in a narrow range of pitch and cell thickness combinations, a…
The local distributions of magnetization in ${\mathrm{V}}_{3}$${\mathrm{O}}_{5}$, ${\mathrm{V}}_{5}$${\mathrm{O}}_{9}$, ${\mathrm{V}}_{6}$${\mathrm{O}}_{11}$, and ${\mathrm{V}}_{6}$${\mathrm{O}}_{13}$ have been determined in their metallic, insulating, and antiferromagnetic insulating phases by means of $^{51}\mathrm{…
The electronic structure of GeO2 and SiO2 has been studied by ultraviolet photoemission spectroscopy (UPS) and electron energy loss spectroscopy (ELS) using thermally grown films prepared in ultrahigh vacuum (p ∼ 10−10 Torr). A consistent energy level model of both filled and empty states is constructed from the UPS a…
The photoelectron energy distribution curves for CuCl, CuBr, CuI, and AgI have been measured for $\ensuremath{\hbar}\ensuremath{\omega}=16.8, 21.2, 26.9, 40.8, 48.4, \mathrm{and} 1486.6$ eV. By exploiting the strong dependence on $\ensuremath{\hbar}\ensuremath{\omega}$ of the photoionization cross sections of the atom…
We have made measurements of the Hall effect and resistivity as well as of thermoelectric power in the temperature range 300–450 K. The results of these measurements are interpreted in terms of a small polaron model of conduction. Additionally, our resistivity and thermoelectric power measurements were extended to 120…
The crystal structure of DL-serine has been refined on the basis of 964 independent reflections measured on an X-ray diffractometer. The refinement has converged to an R index of 0.032, with anisotropic temperature factors for all atoms including hydrogens. The resulting coordinates of the heavy atoms are in good agre…
Optical constants of dry films of deoxyribonucleic acid (sodium salt of calf thymus DNA) have been determined in the 2–82 eV region of photon energy. The extinction coefficient k was obtained by transmission measurements on thin films on metal mesh screens. The refractive index n in the nonabsorbing region 2–4 eV was…
Fluorescence, excitation, and pulsed fluorescence measurements have been made on a single crystal of CaWO4 over a wide temperature range. The temperature dependences of the integrated fluorescence intensities and lifetimes were obtained for different excitation wavelengths. A sharp increase in the fluorescence lifetim…
The nature of the defects produced in noncrystalline SiO2 and α-quartz single crystals by fast neutron irradiation (E > 0.18 MeV) has been investigated by Raman and infrared spectroscopy, small-angle x-ray scattering, and electron microscopy. Measurements were made at 25°C on samples irradiated to integrated fl…
The anisotropy of the translational self-diffusion tensor in the smectic-$A$ ($\frac{〈{D}_{\ensuremath{\parallel}}〉}{〈{D}_{\ensuremath{\perp}}〉}=0.3$) and smectic-$C$ phases of terephthal-bis-4-$n$-butylaniline has been determined by multipulse NMR. The experimental results are interpreted in terms of a pseudolattice…
The growth rate of anorthite crystals from the melt is studied as a function of temperature with undercooling in the ranges 52-152 and 402-652 degrees C. The triclinic form is invariably observed as the crystallization product, growth is preferentially in the c direction, and the interface morphology is faceted. Signi…
The V 0 centre in magnesium oxide consists of two holes trapped by a magnesium vacancy. The hyperfine spectrum due to interactions between this S=1 spin system and two equivalent neighbouring 25 Mg axial nuclei has been observed and values for the isotropic and anisotropic hyperfine parameters and the nuclear quadrupo…
The unusual ferroelectric, magnetic, dynamical and structural properties exhibited by the boracites have attracted increasing attention over recent years. Also of recent interest has been the nature of phase transitions involving more than one order parameter. Boracites are believed to afford examples of such transiti…