Materials Literature
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KNaSO4: trigonal, P3ml , a = 5.6066 (7), c = 7.177(1) A, Z = 2, D x = 2.69 Mg m -a. K3Na(SO4)2: trigonal, P3ml, a = 5.6801 (6), c 7.309 (3) A, Z = 1, D x = 2.70 Mg m -3. Crystals of both compounds were synthesized by heating a mixture of K2SO 4 and Na2SO4 in a Pt crucible at 1273 K for 2 h. Colourless transparent pris…
Angle-resolved photoelectron spectroscopy utilizing polarized synchrotron radiation has been used to determine the electronic energy states of Ni. The dispersion of the $\mathrm{sp}$ band and all of the high-symmetry points in the Ni band structure have been determined. The linewidth in the spectra from the various hi…
The nature of the unpaired electron states in the dimerized phase of the crystalline organic semiconductor N-methyl-N-ethylmorpholinium-tetracyanoquinodimethane [MEM${(\mathrm{TCNQ})}_{2}$] is investigated by the combined means of polarized-optical-reflectance measurements and microscopic theoretical analysis. It is f…
Analytical and numerical analyses have been made of the physical behaviour of a collapsing bubble in a liquid. The mathematical formulation takes into account the effects of compressibility of the liquid, non-equilibrium condensation of the vapour, heat conduction and the temperature discontinuity at the phase interfa…
A SEM-EBIC minority-carrier lifetime-measurement method is described, whereby an arrangement is used such that the electron beam is incident normal to the charge-collecting barrier; the barrier may be either that of a Schottky diode or of a very shallow p-n junction. The beam is positioned at a constant point over the…
A simple model is found for the anomalous density dependence of electron mobilities by applying the energy shift and broadening of multiple scattering theory plus the uncertainty principle to the transport equations. The shift alone when properly applied immediately predicts the observed positive and negative effects…
Cerium and light actinide monopnictides of NaCl structure have extraordinarily strong magnetic anisotropy, with unusual magnetic structures and transitions. We show that this behavior can be understood on the basis of a Coqblin-Schrieffer-type interaction, effectively treating mixing of $f$ and conduction electrons.
Dielectric breakdown of poly(vinylidene-fluoride) (PVDF) is studied over the temperature range from room temperature to 150 degrees C, by applying a linearly rising voltage. The electric strength is in excess of 8 MV cm -1 at room temperature, but above 50 degrees C it rapidly falls inversely with temperature and depe…
This Letter reports the first experimental study of the spatial structure of spontaneous thermal fluctuations for $\mathrm{ka}\ensuremath{\gtrsim}1$ in a physical system maintained in a nonequilibrium steady state. In particular, the shear-flow-induced distortion of the static structure factor, $\mathcal{S}(\stackrel{…
A simple model of eutectic solidification is used to illustrate the marginal-stability theory of pattern selection in nonequilibrium processes. The nonlinear equation of motion which describes this model suggests a mechanism for noise amplification at the marginally stable operating point of the system.
Radiation-induced defects in LiYF 4 have been studied using optical and ESR techniques. A pi -polarised absorption band at 3.99 eV is identified as the (F 2 - ) centre. An optical band at 3.70 eV has polarisation properties characteristic of dipoles oriented in the direction of Y 3+ -Y 3+ pairs. This band is a candida…
Molecular dynamics simulations have been performed in order to study fast-ion conduction in solid SrCl 2 over a range of temperatures and densities. The simulations are carried out on a system of 324 ions interacting through rigid-ion potentials. The anion diffusion constant increases from a very small value to a valu…
The manganese phosphide, MnP, is a typical 3d intermetallic compound. The authors report a self-consistent APW calculation of the spin-polarised energy band structure for MnP. A one-electron potential is constructed by the local-spin-density approximation. For a minority spin electron, bands near the Fermi energy, E F…
For pt.I see ibid., vol.13, no.10, p.1901 (1980). A molecular dynamics study of fast-ion conduction in SrCl 2 is continued. The average distributions of cations and anions in the unit cell at temperatures just below, and several hundred degrees above, the simulated transition temperature are compared. Even in the high…
The results of ENDOR investigations of magnetically dilute single crystals of Ag(II) and Cu(II) tetraphenylporphyrins (TPP) are presented and discussed. The complete hyperfine tensors, and quadrupole tensor for nitrogen, have been determined for the metal ions, nitrogens and pyrrole protons. The non-first order 14N EN…
The temperature dependence of structural and magnetic order parameters of ferroelectric-antiferromagnetic BiFeO 3 with rhombohedral perovskite structure is investigated by means of neutron diffraction on a powder sample. The tilt angle of oxygen octahedra decreases from 12.5 degrees at 4.2K to 11.4 degrees at 878K. As…
Temperature dependence of the Raman spectrum of AgNa(NO 2 ) 2 has been studied. At low temperatures, the ν 2 -spectrum due to the bending vibration of the NO - 2 ions in the crystal consists of two components at 832 and 858 cm -1 . With increasing temperature, the third component becomes appreciable at 845 cm -1 near…
Loeb retracted his support for Hermstein's negative ions cloud theory and proposed that the reduction of electric field at the anode, due to the presence of positive ions space charge, could be responsible for the corona-stabilization in electronegative gases. Based on this comment, Abdel-Salam et al. proposed a semi-…
A novel method is presented for correcting the defocusing and aberrations by means of the eight-pole stigmator, compensating both astigmatism and coma aberrations by second and third order astigmatisms in addition to the dynamic focusing. Owing to the electronic feedback circuit compensating the defocus and deflection…
The crystal structures of Sb 2 Tl 7 , Cu 5 Zn 8 , and Ir 3 Ge 7 are discussed with the aid of shortest distances of Dirichlet domains and of voids in their frameworks. It will be pointed out that all three frameworks must be regarded as different though relations between the atomic parameters are obvious. The Sb 2 Tl…