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Sustainable consumption: towards action and impact. : International scientific conference November 6th-8th 2011, Hamburg - European Green Capital 2011, Germany: abstract volume
- This volume contains the abstracts of all oral and poster presentations of the international scientific conference „Sustainable Consumption – Towards Action and Impact“ held in Hamburg (Germany) on November 6th-8th 2011. This unique conference aims to promote a comprehensive academic discourse on issues concerning sustainable consumption and brings together scholars from a wide range of academic disciplines.
Übersicht über im Herbst 2003 laufende Forschungsprojekte im E-Finance Lab
Nonthermal phase transitions in semiconductors induced by a femtosecond extreme ultraviolet laser pulse
Harald O. Jeschke
- Part of Focus on High Energy Density Physics. In this paper, we present a novel theoretical approach, which allows the study of nonequilibrium dynamics of both electrons and atoms/ions within free-electron laser excited semiconductors at femtosecond time scales. The approach consists of the Monte-Carlo method treating photoabsorption, high-energy-electron and core-hole kinetics and relaxation processes. Low-energy electrons localized within the valence and conduction bands of the target are treated with a temperature equation, including source terms, defined by the exchange of energy and particles with high-energy electrons and atoms. We follow the atomic motion with the molecular dynamics method on the changing potential energy surface. The changes of the potential energy surface and of the electron band structure are calculated at each time step with the help of the tight-binding method. Such a combination of methods enables investigation of nonequilibrium structural changes within materials under extreme ultraviolet (XUV) femtosecond irradiation. Our analysis performed for diamond irradiated with an XUV femtosecond laser pulse predicts for the first time in this wavelength regime the nonthermal phase transition from diamond to graphite. Similar to the case of visible light irradiation, this transition takes place within a few tens of femtoseconds and is caused by changes of the interatomic potential induced by ultrafast electronic excitations. It thus occurs well before the heating stimulated by electron–phonon coupling starts to play a role. This allows us to conclude that this transition is nonthermal and represents a general mechanism of the response of solids to ultrafast electron excitations.
Zoo Basel Newsletter. 2013, Juni
Integer point sets minimizing average pairwise L1 distance: What is the optimal shape of a town?
Erik D. Demaine
Sándor P. Fekete
- An n-town, n[is an element of]N , is a group of n buildings, each occupying a distinct position on a 2-dimensional integer grid. If we measure the distance between two buildings along the axis-parallel street grid, then an n-town has optimal shape if the sum of all pairwise Manhattan distances is minimized. This problem has been studied for cities, i.e., the limiting case of very large n. For cities, it is known that the optimal shape can be described by a differential equation, for which no closed-form solution is known. We show that optimal n-towns can be computed in O(n[superscript 7.5]) time. This is also practically useful, as it allows us to compute optimal solutions up to n=80.
CAST constraints on the axion-electron coupling
José Manuel Carmona
Juan I. Collar
Luigi Di Lella
J. A. García
Michael D. Hasinoff
Fritz Herbert Heinsius
Dieter H.H. Hoffmann
Igor Garcia Irastorza
David W. Miller
Mike J. Pivovaroff
Karl van Bibber
Joaquin D. Vieira
José A. Villar
Julia K. Vogel
- In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axiorecombination, the “BCA processes.” Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling gae and axion-photon interaction strength ga using the CAST phase-I data (vacuum phase). For ma <~ 10 meV/c2 we find ga gae < 8.1 × 10−23 GeV−1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission.
Humaira Masood Siddiqi
- The aromatic rings in the title compound, C13H8ClNO4, enclose a dihedral angle of 39.53 (3)°. The nitro group is almost coplanar with the ring to which it is attached [dihedral angle = 4.31 (1)°]. In the crystal, molecules are connected by C-H...O hydrogen bonds into chains running along . Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 A°; R factor = 0.044; wR factor = 0.105; data-to-parameter ratio = 18.9.
Electron Supersurface Scattering On Polycrystalline Au
Wolfgang S. M. Werner
- Supersurface electron scattering, i.e., electron energy losses and associated deflections in vacuum above the surface of a medium, is shown to contribute significantly to electron spectra. We have obtained experimental verification (in absolute units) of theoretical predictions that the angular distribution of the supersurface backscattering probability exhibits strong oscillations which are anticorrelated with the generalized Ramsauer-Townsend minima in the backscattering probability. We have investigated 500-eV electron backscattering from an Au surface for an incidence angle of 70° and scattering angles between 37° and 165°. After removing the contribution of supersurface scattering from the experimental data, the resulting angular and energy distribution agrees with the Landau-Goudsmit-Saunderson (LGS) theory, which was proposed about 60 years ago, while the raw data are anticorrelated with LGS theory. This result implies that supersurface scattering is an essential phenomenon for quantitative understanding of electron spectra.
A review of the New World Krisnini (Hemiptera: Cicadellidae: Iassinae) including three genera and six new species
Paul H. Freytag
- The tribe Krisnini (Hemiptera: Cicadellidae) is presently known in the New World from three species from Puerto Rico and one species from Dominican Amber, all described in the Old World genus Krisna Baker. The three species from Puerto Rico are being placed in Lipokrisna, new genus, with Krisna insularis Oman as the type species, becoming Lipokrisna insularis (Oman), new combination. The other species in this genus are L. montana (Caldwell) and L. aesta (DeLong) both new combinations. The one species from Dominican amber is placed in the Genus Archiokrisna, new genus, with Krisna garciamarquezi Dietrich as the type species, becoming Archiokrisna garciamarquezi (Dietrich), new combination. The genus, Neokrisna, new genus, is described for six new species from the Dominican Republic, with Neokrisna oncora, new species, as the type species. The other new species in the genus are N. breva, N. decliva, N. libera, N. longula, and N. stena. A key to the species of Neokrisna is included. The three genera are compared with each other and the old World genus Krisna.
Spin modulation instabilities and phase separation dynamics in trapped two-component Bose condensates
Nicolaas Jan van Druten
- n the study of trapped two-component Bose gases, a widely used dynamical protocol is to start from the ground state of a one-component condensate and then switch half the atoms into another hyperfine state. The slightly different intra-component and inter-component interactions can then lead to highly non-trivial dynamics, especially in the density mismatch between the two components, commonly referred to as 'spin' density. We study and classify the possible subsequent dynamics, over a wide variety of parameters spanned by the trap strength and by the inter- to intra-component interaction ratio. A stability analysis suited to the trapped situation provides us with a framework to explain the various types of dynamics in different regimes.