Now showing items 129-148 of 497

  • Estimation of the urban heat island for UK climate change projections 

    Kershaw, Tristan; Sanderson, M.; Coley, David; Eames, Matthew E. (SAGE Publications, 2010)
    Cities are known to exert a significant influence on their local climate, and are generally warmer than their surroundings. However, climate models generally do not include a representation of urban areas, and so climate ...
  • Evaporation of the planet HD 189733b observed in H I Lyman-α 

    Lecavelier des Etangs, A.; Ehrenreich, D.; Vidal-Madjar, A.; Ballester, G.; Desert, J.-M.; Ferlet, R.; Hebrard, G.; Sing, David K.; Tchakoumegni, K.-O.; Udry, S. (EDP Sciences for European Southern Observatory (ESO), 2010)
    We observed three transits of the extrasolar planet HD 189733b in H i Lyman-α and in a few other lines in the ultraviolet with HST/ACS, in the search for atmospheric signatures. We detect a transit signature in the Lyman-α ...
  • Evidence for hot electron magnetocurrent in a double barrier tunnel junction device 

    Ladak, S.; Hicken, R.J. (2005)
    Hot electron transport has been studied in three terminal Ta/TaOx/Co/AlOx/Ni81Fe19 structures fabricated by magnetron sputtering through shadow masks. With the Co base and Ta collector connected together via a small resistor, ...
  • Evidence for Magnetic Flux Saturation in Rapidly Rotating M Stars 

    Reiners, A.; Basri, G.; Browning, Matthew K. (American Astronomical Society / IOP Publishing, 2009)
    We present magnetic flux measurements in seven rapidly rotating M dwarfs. Our sample stars have X-ray and Hα emission indicative of saturated emission, i.e., emission at a high level, independent of rotation rate. Our ...
  • Evidence of a barrier oxidation dependence on the interfacial magnetism in Co/alumina based magnetic tunnel junctions 

    Telling, N.D.; van der Laan, Gerrit; Ladak, S.; Hicken, R.J.; Arenholz, E. (American Institute of Physics, 2006)
    Soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co L-2,L-3 edge have been applied to explore the near-interfacial magnetism of Co electrodes in Co/alumina based magnetic tunnel junctions. By taking ...
  • Evidence of local moment formation in Co-based Heusler alloys 

    Telling, N.D.; Keatley, Paul Steven; van der Laan, Gerrit; Hicken, R.J.; Arenholz, E.; Sakuraba, Y.; Oogane, M.; Ando, Y.; Takanashi, K.; Sakuma, A.; Miyazaki, T. (American Physical Society, 2008)
    We examine the formation of local moments in Heusler alloys of the composition Co(2)MnZ (where Z=Si or Al) using the combined techniques of x-ray magnetic circular and linear dichroism. The existence of local moments in ...
  • Evolutionary models for solar metallicity low-mass stars: mass-magnitude relationships and color-magnitude diagrams 

    Baraffe, I.; Chabrier, G.; Allard, F.; Hauschildt, P. (EDP Sciences for European Southern Observatory (ESO), 1998)
  • Exactly-solvable problems for two-dimensional excitons 

    Parfitt, D.G.W.; Portnoi, M.E. (Nova Science Publishers, 2004)
    Several problems in mathematical physics relating to excitons in two dimensions are considered. First, a fascinating numerical result from a theoretical treatment of screened excitons stimulates a re-evaluation of the ...
  • Excitation and Imaging of Precessional Modes in Soft-Magnetic Squares 

    Neudert, A.; Keatley, Paul Steven; Kruglyak, V.V.; McCord, Jeffrey; Hicken, R.J. (Institute of Electrical and Electronics Engineers (IEEE), 2008)
    We investigated the high-frequency modes of 40 mum wide, 160 nm thick Fe 70Co8B12Si10 squares using time-resolved scanning Kerr microscopy. Two modes were identified using pulsed field excitation while the spatial character ...
  • Excitation of propagating spin waves with global uniform microwave fields 

    Au, Y.; Davison, T.; Ahmad, E.; Keatley, Paul Steven; Hicken, R.J.; Kruglyak, V.V. (American Institute of Physics, 2011)
    We demonstrate a magnonic architecture that converts global free-space uniform microwaves into spin waves propagating in a stripe magnonic waveguide. The architecture is based upon dispersion mismatch between the narrow ...
  • Excitation of remarkably nondispersive surface plasmons on a nondiffracting, dual-pitch metal grating 

    Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Institute of Physics, 2002)
    A nondiffracting metallic lamellar grating formed from three equally spaced grooves per repeat period, with one being slightly shallower than the other two is examined at microwave frequencies. When filled with a slightly ...
  • Exciton and electron-hole plasma formation dynamics in ZnO 

    Hendry, Euan; Koeberg, Mattijs; Bonn, Mischa (American Physical Society, 2007)
    We employ optical pump-THz probe measurements to study the formation of excitons and electron-hole plasmas following photogeneration of a hot electron-hole gas in the direct gap semiconductor zinc oxide. Below the Mott ...
  • Exciton storage in a nanoscale Aharonov-Bohm ring with electric field tuning 

    Fischer, Andrea M.; Campo, Vivaldo L.; Portnoi, M.E.; Römer, Rudolf A. (American Physical Society, 2009)
    We study analytically the optical properties of a simple model for an electron-hole pair on a ring subjected to perpendicular magnetic flux and in-plane electric field. We show how to tune this excitonic system from optically ...
  • Excitons and interband terahertz transitions in narrow-gap carbon nanotubes 

    Portnoi, M.E.; Downing, C.A.; Hartmann, Richard R.; Shelykh, I.A. (Institute of Electrical and Electronics Engineers (IEEE), 2013)
    We show, via a solution of the quasi-one-dimensional two-body problem applied to a Dirac system, that excitonic effects suppress the one-dimensional Van Hove singularity in single-walled carbon nanotubes with narrow band gaps.
  • Excitons in narrow-gap carbon nanotubes 

    Hartmann, Richard R.; Shelykh, I.A.; Portnoi, M.E. (American Physical Society, 2011)
    We calculate the exciton binding energy in single-walled carbon nanotubes with narrow band gaps, accounting for the quasirelativistic dispersion of electrons and holes. Exact analytical solutions of the quantum relativistic ...
  • Experimental method for reliably establishing the refractive index of buprestid beetle exocuticle 

    Noyes, Joseph Alexander; Vukusic, Peter; Hooper, Ian R. (Optical Society of America, 2007)
    In this study we apply an existing optical characterisation technique to establish reliably the complex refractive indices of layers comprising a natural multilayer reflector in the beetle Chrysochroa raja. Its reflector ...
  • Experimental verification of total absorption by a low-loss thin dielectric layer 

    Díaz-Rubio, Ana; Hibbins, Alastair P.; Carbonell, Jorge; Sanchez-Dehesa, Jose (American Institute of Physics (AIP), 2015)
    This work presents an experimental demonstration of total absorption by a metal-dielectric metasurface. Following a theoretical proposal [Díaz-Rubio et al., Phys. Rev. B 89, 245123 (2014)], we have designed and fabricated ...
  • Exploration of the surface director profile in a liquid crystal cell using coupling between the surface plasmon and half-leaky optical guided modes 

    Yang, Fuzi; Ruan, Lizhen; Sambles, J. Roy (American Institute of Physics, 2008)
    The half-leaky guided mode geometry with a thin metal tunnel barrier as one cladding layer is used to explore the distribution of the director very near to the surface in a hybrid aligning nematic liquid crystal cell. From ...
  • Ferrite-filled cavities for compact planar resonators 

    Keatley, Paul Steven; Durrant, C.J.; Berry, S.J.; Sirotkin, Evgeny; Hibbins, Alastair P.; Hicken, R.J. (American Institute of Physics (AIP) -, 2014)
    Sub-wavelength metallic planar cavities, closed at one end, have been constructed by wrapping aluminium foil around teflon or ferrite slabs. Finite cavity width perturbs the fundamental cavity mode frequency of ferrite-filled ...
  • Ferromagnetic microswimmers 

    Ogrin, Feodor Y.; Petrov, Peter G.; Winlove, C. Peter (American Physical Society, 2008)
    We propose a model for a novel artificial low Reynolds number swimmer, based on the magnetic interactions of a pair of ferromagnetic particles: one with hard and the other with soft magnetic properties, connected by a ...