Self-consistent, first-principles calculations are presented for the electronic structure of some point defects in the binary alloys CoAl and CoGa. All possible structural defects-i.e., antistructure atoms and vacancies-as well as 3d transition-metal impurities on both sublattices are considered. The calculations are based on the Korringa-Kohn-Rostoker Green's-function method and on density-functional theory in the local-spin-density approximation. The calculated densities of states, charge transfers, and magnetic moments are discussed and compared with the results of other theoretical calculations and the available experimental data.
Kamp, [Kamberidou] Irene(1987). Beautiful and Shining (Antique Jewellery). Athena Magazine, Publication of the International Studies Association, no. 12, January 1987:24-25.
ATHENA MAGAZINE, MONTHLY REVIEW OF CURRENT AFFAIRS. Publication of the International Studies Association, Athens (1986-1987) Editorial Board: Dimitris Constas, Vice Rector of the Pantios School of Political Science, Athens; Theodore Couloumbis, Professor of International Relations, University of Thesssaloniki; Paschalis Kitromilides, Associate Professor of Political Science, University of Athens; Christos Rozakis, Professor of International Relations, Pantios School of Political Science; Thanos Veremis, Associate Professor of History, University of Athens
Kamberidou (Kamp), Irene(1987). Beautiful and Shining (Antique Jewellery). Athena Magazine, Publication of the International Studies Association, no. 12, January 1987:24-25.
Kamberidou (Kamp), Irene(1986). Antique fashion is never too old. Athena Magazine, Publication of the International Studies Association, no. 4, May 1986: 132-133.
Kamberidou (Kamp), Irene (1986). Life in Ancient Times. What they wore and how. Athena Magazine, Publication of the International Studies Association, no. 7, August 1986: 240-241.
Kamberidou (Kamp), Irene (1986). Meetings: Women teach Women. Athena Magazine, Publication of the International Studies Association, no 8, Sept. 1986: 258.
The existence of binary clusters in the Large Magellanic Cloud has been discussed recently. A survey of the LMC on UKSTU plates yielded a total of 69 pairs of clusters with a center-to-centre separation of less than ≡18 pc (for a distance modulus of 18.4 for the LMC). Statistical arguments suggest that taking chance line-ups into account, a significant fraction of the pairs found must be physically associated at the 7σ level. A series of observations have been undertaken in order to establish the physical association of the pairs.
We report about self-consistent calculations for dilute Ni alloys, which are based on density-functional theory and the Korringa-Kohn-Rostoker Green's-function method. In particular, we calculate the charge and magnetization perturbations for four shells of atoms around the impurity. Impurities of the 3d, 4d, and 4sp series are considered. Of central interest is the transition from strong to weak ferromagnetism and the different screening mechanism in these alloys. We compare our results for the perturbations of the local moments as well as the change of the total moment with magnetization and neutron scattering data.
A detailed model for positron production by a young pulsar is presented. It is shown that electromagnetic cascades can develop in a young pulsar's magnetosphere, and the model results are applied to the pulsar which is hypothesized to lie near the Galactic center. It is found that such a pulsar would be expected to produce relatively low energy electron-positron pairs with an efficiency rating high enough to explain the observed luminosity of the Galactic center annihilation line. Virtually all of the gamma ray continuum radiation produced in the cascades would be beamed along the magnetic poles of the neutron star, and therefore probably would not be observed from earth. Some observational predictions generated by the proposed model for the Galactic center positron source are given.
We consider the electronic structure of dilute Pd and discuss reasons for the disagreement between experiment and theory, especially concerning the Pd density of states. The intensity of the low energy Pd peak, obtained in previous calculations, is very sensitive to charge transfer, lattice relaxation and relativistic effects. Realistic ab-initio calculations, which take these effects properly into account, practically remove the intensity of the low energy Pd peak and are in much better agreement with experiments than previous single site and KKR-CPA results.
An expression for the interaction energy between two defects in a metallic compound within the framework of the frozen potential approximation is presented. The numerical application to vacancies in Al or TAl (T=Fe, Ni) shows that the electrostatic contribution of the screening charge around each defect can predominate over the one-particle term.
High-energy (70 MeV < E < 5 GeV) gamma-ray observations of Cyg X-3 by the ESA satellite COS-B and hard X-ray (14 keV < E < 140 keV) observations by the Leiden-MIT balloon experiment, Leimit, are presented. A comparison with, and a study of earlier results over the 14 decades in energy from 1 keV up to ≡1017eV indicates that the strong variability of Cyg X-3 over more than one order of magnitude at energies below 20 keV does not exhibit itself in the data collected at hard X-ray energies, and the power emitted per decade of energy reaches a minimum in the MeV-GeV region. If the primary gamma-rays up to 1015eV originate close to the central source, absorption by the keV X-rays in the Cyg X-3 binary system could explain the latter phenomenon.
An investigation of the star clusters in the outermost areas of the LMC has started in order to examine the observed dynamical properties of the halo globular clusters in this galaxy. A first sample of 38 clusters have been measured by means of star counts on plates taken with the 1.2 m U.K. Schmidt telescope. The derived tidal radii and masses are comparable to those found for the disk young clusters of the LMC and those of the galactic globulars.
We develop a formalism to take into account the lattice relaxation around an impurity within the Korringa-Kohn-Rostoker Green's-function method. Using this formalism and the density-functional theory in the local spin-density approximation we perform first-principles, self-consistent calculations for the electronic structure of some dilute metallic alloys. In particular, we investigate the influence of lattice relaxations on the local magnetic moments in CuMn, CuFe, CuCo, and NiMn.
Καμπερίδου, Ειρήνη (1987). Αϊ Khanum: Η Ελλάδα στο «τέλος του κόσμου». ΑΥΓΗ (Κυριακάτικη), 25 Ιανουαρίου 1987), σελ. 22 (εξώφυλλο/ οπισθόφυλλο /τελευταία σελίδα εφημερίδας).