Materials Literature
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The validity of Kondorsky’s switching field distribution for pinning magnets with rectangular hysteresis loops is extended to cases where the hysteresis loops are influenced by reversible rotation of the magnetization vectors in the domains. Caused by this influence, the monotonic Kondorsky function changes to modifie…
The influence of disorder on shear viscosity of undercooled melts is described by the formula η=η0⋅exp(θ/T )a. It is shown that this expression reproduces the existing experimental data with a reasonable accuracy for a broad range of substances of various nature (silicates, borates, germanates, phosphates, Se, glucose…
Specular and nonspecular absolute x-ray-reflectivity measurements have been performed on the Au(001) surface between T=300 and 1250 K. At all temperatures the surface-normal vibrational amplitudes are increased above the corresponding bulk thermal vibrational amplitude (Debye-Waller factor). Below T=1170 K, the surfac…
We study transitions to periodic structures in block copolymers melts, including concentration fluctuations self-consistently in the analysis. Phase diagrams are constructed for diblock and triblock copolymers of finite molecular weight. The concentration fluctuations increase the stability of the isotropic state, and…
If a surface-modulated diffraction grating is arranged so that the scattering vector does not lie in the plane of incidence of the illuminating radiation, then polarization conversion can occur. This conversion can be strongly enhanced if a surface mode, such as a surface-plasmon-polariton or guided mode, is excited a…
We present high-resolution 2p x-ray-absorption spectra from 3d transition metals M in three series of pseudobinary and pseudoternary oxides. We show how the detailed shape of the multiplet within the spectra can be used to determine the valence of the M ions. The spectra of the early-transition-metal compounds show dr…
Intense, low-frequency Raman scattering from localized acoustic vibrations of small, spherical Ag particles embedded in ${\mathrm{SiO}}_{2}$ thin films has been observed. It was found that the Raman peak shifts to higher frequencies as the particle size decreases. For Ag particles smaller than 4 nm, the size dependenc…
The ac conduction in NiO films has been investigated in the frequency range 10 Hz${10}^{9}$ Hz and at temperatures between 10 and 300 K. The frequency and the temperature dependence of the electrical conductivity can be consistently explained within a model developed for the mechanism of charge transfer in amorphous s…
Films of tin oxide (${\mathrm{SnO}}_{2}$) were deposited on a quartz substrate by the chemical-vapor-deposition technique. Carrier densities in the range 6.1\ifmmode\times\else\texttimes\fi{}${10}^{19}$--1.3\ifmmode\times\else\texttimes\fi{}${10}^{21}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ were obtained by varyin…
Sm–Fe alloys have been produced by rapid quenching and the resulting phases have been investigated in the as-quenched state and after nitriding. Besides the well-known equilibrium phases of the binary Sm–Fe system (Fe, Sm2Fe17, SmFe3, SmFe2 and Sm), a hexagonal TbCu7-type phase shows up in melt spun ribbons (a=4.88 Å,…
By means of time-of-flight inelastic neutron scattering we have studied two samples with nominal compositions Al 62 Cu 25.5 Fe 12.5 (perfect sample) and Al 63 Cu 24.5 Fe 12.5 (imperfect sample). The former is a perfect quasi-crystal with sharp Bragg peaks over the whole temperature range from room temperature up to 80…
Effective thermal conductivities of three-phase systems have been experimentally determined by a differential temperature sensors method. The results are in good agreement with the values predicted by the geometry-dependent resistor model developed for three-phase systems. Reported values of ETC in the literature are…
Luminescence decay curves from the 5 D 0 state of the cubic hexachloroelpasolite crystals Cs 2 NaEuCl 6 have been measured over the temperature range 12-340 K. The decay curves are markedly non-exponential, especially at low temperatures and are not well described by standard kinetic treatments. Energy migration in th…
Analysis of the Frank free energy for nematics confined to cylindrical regions indicates that the director pattern is dependent on the surface elastic constant ${\mathit{K}}_{24}$ if there is weak normal anchoring and escape along the cylinder axis. Using deuterium nuclear-magnetic-resonance techniques on samples of s…
The continuous-filament ceramic composite is becoming recognized as necessary for new, high-temperature structural applications. Yet because of the susceptibility of the filaments to damage from traditional methods for the preparation of ceramics, vapor-phase infiltration has become the fabrication method of choice. T…
Abstract The permeability of four structurally related poly(alkoxyphosphazenes), three isomers of poly(dibutoxyphosphazenes) (PBuP), and poly(di‐neopentyloxyphosphazene) (Pneo‐PeP), to 13 gases has been determined by the time‐lag method. Systematic variations in chemical structure have shown a large effect of side cha…
The structures of NADP+ and magnesium isocitrate bound to the NADP(+)-dependent isocitrate dehydrogenase of Escherichia coli have been determined and refined at 2.5-A resolution. NADP+ is bound by the large domain of isocitrate dehydrogenase, a structure that has little similarity to the supersecondary structure of th…
Domains and discommensurations have been directly observed by transmission electron microscopy in some dark-field images using certain reflections in a Mn-Si-Al octagonal quasicrystal. The invisibility and visibility of domains and discommensurations separate the diffraction spots into basic and satellite reflections.…
The absorption spectra of the Nd 3+ ion in the tetragonal xenotime-type NdVO 4 and in the monoclinic monazite-type LaVO 4 , LaPO 4 and NdPO 4 as well as the luminescence of the Eu 3+ ion in LaVO 4 and LaPO 4 were measured and the spectra were analysed according to the appropriate symmetry of the RE site. In addition t…
The energies and wave functions of both the ground and excited states are calculated for a proton in KDP (${\mathrm{KH}}_{2}$${\mathrm{PO}}_{4}$) and a deuteron in DKDP (${\mathrm{KD}}_{2}$${\mathrm{PO}}_{4}$), respectively. On the basis of these calculations, the isotope effects on the saturated polarization and the…