Polarized endomorphisms of complex normal varieties

It is shown that a complex normal projective variety has non-positive Kodaira dimension if it admits a non-isomorphic quasi-polarized endomorphism. The geometric structure of the variety is described by methods of equivariant lifting and fibrations.     

Double internal bremsstrahlung in the electron-capture decay of 55Fe

The energy distribution of photons emitted in double internal bremsstrahlung accompanying the electron-capture decay of ⁵⁵Fe has been investigated. For sum photon energies in the range of 44–230 keV and at an emission angle of 90°, the ratio of transition probabilities of double to single internal bremsstrahlung processes has been found to be (5.6±0.5) × 10^?5. The experimental data are compared with the existing theoretical predictions.     

Sensitization of ZnO photoconductivity by chemical modification of surface states

Surface States on ZnO have been investigated through their effect on photoconductivity. Low energy photons (0·7 ～ 1·5 eV) are found to induce a feeble photocurrent in ZnO which is attributable to the direct electron injection from surface levels to the conduction band. A definite correlation has been found between the i.r. induced photocurrent and the intrinsic or the dye sensitized photocurrent excited by UV or visible radiation. It is proposed that phthalic anhydride on ZnO modifies the distribution of surface levels, by a chemical interaction with chemisorbed oxygen. Surface levels originating in chemisorbed oxygen ions are transformed by phthalic anhydride into new levels which are shallower but thermally more stable. These traps are found to enhance the photoconductivity of ZnO. The chemical nature of them and the mechanism of sensitization are discussed.     

Solid-liquid separation after liquid-liquid extraction

A low-melting solid is used as organic solvent for liquid-liquid extraction at elevated temperatures followed by solidification and decantation of the aqueous phase.     

Enhanced scattering from a thin film with one-dimensional disorder

This paper deals with a TE plane wave scattering from a thin film with one-dimensional disorder by means of the stochastic functional approach. The thin film is one-dimensionally inhomogeneous in the horizontal direction with infinite extent, and is homogeneous in the vertical direction with finite thickness. Based on an approximate wavefield representation in terms of a Wiener-Hermite expansion in a preceding paper (Tamura et al., 2004, Waves in Random Media, 14, 435-465), the first- and second-order incoherent scattering cross-sections are presented in explicit forms and scattering properties are discussed. The scattering properties vary entirely with the film thickness. In a case where the thickness is smaller than a few wavelengths in the thin film, enhanced scattering and associated enhanced scattering may appear as sharp peaks or dips on the second-order incoherent scattering distribution if the thin film has guided wave modes. When the thickness becomes sufficiently larger than the wavelength inside the film, a new enhanced scattering phenomenon appears as gentle peaks on the second-order incoherent scattering distribution in four special directions. Such four directions are the directions of forward scattering, specular reflection, backscattering, and the symmetrical direction of forward scattering with respect to the normal of the film surface.The first-order incoherent scattering occurs distinctly in four such directions. Such enhanced scattering is independent of the existence of the guided wave modes inside the thin film, and deeply relates to the structure of the thin film with one-dimensional disorder that has infinite correlation in the vertical direction. For SiC and glass thin films having one-dimensional disorder with a Gaussian correlation and three types of exponential correlation, the first- and second-order incoherent scattering cross-sections are illustrated in figures. The narrow enhanced scattering peaks appear for the glass film in a thin case. The gentle enhanced peaks turn up for both the SiC and glass films in a thick case. Furthermore, the optical theorem is calculated for several cases. It is then found that the error of the optical theorem decreases and the performance of the wavefield is improved by taking into account the second-order incoherent scattering.     

A variational approach to dynamics of simple ionic crystals at high temperatures

The variational theory of anharmonic lattice dynamics is applied to the sodium chloride structure. The Coulomb and the inverse-power repulsive pair potential between ions are used. The mean-square displacements (MSDs) at zero pressure for individual ions, i.e., cation and anion, are calculated as a function of temperature without use of any fit parameters. It is shown that the ratio of the MSDs for anion and cation depends strongly on the ionic-radius ratio. The average MSDs are in reasonably good agreement with the experimental data obtained by a Bragg diffraction technique. A discussion is given of the relation between the divergent behavior of the MSDs which we find at some critical temperature and the observed melting point.A Humboldt fellow on leave of absence from Department of Engineering Science, Hokkaido University, Sapporo 060, Japan     

Geometric consideration of duality in vector optimization

Recently, duality in vector optimization has been attracting the interest of many researchers. In order to derive duality in vector optimization, it seems natural to introduce some vector-valued Lagrangian functions with matrix (or linear operator, in some cases) multipliers. This paper gives an insight into the geometry of vector-valued Lagrangian functions and duality in vector optimization. It is observed that supporting cones for convex sets play a key role, as well as supporting hyperplanes, traditionally used in single-objective optimization.The author would like to express his sincere gratitude to Prof. T. Tanino of Tohoku University and to some anonymous referees for their valuable comments.     

Non-Darcy free convective flow along a vertical cylinder embedded in a porous medium with surface mass flux

The nonsimilar non-Darcian free-convection flow about a vertical cylinder with impermeable surface embedded in a saturated porous medium, where surface temperature of the cylinder varies as x^m, a power function of distance from the leading edge, has been studied by employing the implicit finite-difference method together with the Newton's quasilinearization technique. In the present investigation, effects of the surface mass flux together with the inertial effects on the rate of heat transfer at the surface, on the velocity distribution, and on the temperature distribution are shown graphically.