Effect of annealing temperature on photoluminescence and resistive switching characteristics of ZnO/Al2O3 multilayer nanostructures

This work demonstrates the role of defects generated during rapid thermal annealing of pulsed laser deposited ZnO/Al2O3 multilayer nanostructures in presence of vacuum at different temperatures (Ta) (500���900 C) on their electrical conductance and optical characteristics. Photoluminescence (PL) emissions show the stronger green emission at Ta 600 C and violet���blue emission at TaP800 C, and are attributed to oxygen vacancies and zinc related defects (zinc vacancies and interstitials) respectively. Current���voltage (I���V) characteristics of nanostructures with rich oxygen vacancies and zinc related defects display the electroforming free resistive switching (RS) characteristics. Nanostructures with rich oxygen vacancies exhibit conventional and stable RS behavior with high and low resistance states (HRS/LRS) ratio 104 during the retention test. Besides, the dominant conduction mechanism of HRS and LRS is explained by trap-controlled-space-charge limited conduction mechanism, where the oxygen vacancies act as traps. On the other hand, nanostructures with rich zinc related defects show a diode-like RS behavior. The rectifying ratio is found to be sensitive on the zinc interstitials concentration. It is assumed that the rectifying behavior is due to the electrically formed interface layer ZnAl2O4 at the Zn defects rich ZnO crystals ��� Al2O3 x interface and the switching behavior is attributed to the electron trapping/de-trapping process at zinc vacancies.

Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the H������� and H���ZZ������4��� Decay Channels at s���=8 TeV with the ATLAS Detector

Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb���1 of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of s���=8 TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H������� and H���ZZ������4��� event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be ��pp���H=33.0��5.3(stat)��1.6(sys)pb. The measurements are compared to state-of-the-art predictions.

Measurements of the top quark branching ratios into channels with leptons and quarks with the ATLAS detector

A measurement of the inclusive cross section for top quark pair production in pp collisions using events with an isolated lepton (muon or electron) and a �� lepton decaying to hadrons (��had) is reported. Measurements of the branching ratios of top quark decays into leptons and jets using events with tt�� (top antitop) pairs are also reported. Events were recorded with the ATLAS detector at the LHC in pp collisions at a center-of-mass energy of 7 TeV. The collected data sample corresponds to an integrated luminosity of 4.6 fb���1. The inclusive cross section measured using events with an isolated lepton and a ��had is ��tt��=183��9(stat.)��23(syst.)��3(lumi.)pb. The measured top quark branching ratios agree with the Standard Model predictions within the measurement uncertainties of a few percent.

Searches for Higgs boson pair production in the hh���bb����,����WW���,����bb,bbbb channels with the ATLAS detector

Searches for both resonant and non-resonant Higgs boson pair production are performed in the hh���bb����,����WW��� final states using 20.3 fb���1 of pp collision data at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the Large Hadron Collider. No evidence of their production is observed and 95% confidence level upper limits on the production cross sections are set. These results are then combined with the published results of the hh�������bb,bbbb analyses. An upper limit of 0.69 (0.47) pb on the non-resonant Standard Model like hh production is observed (expected), corresponding to 70 (48) times of the SM gg���hh cross section. For production via narrow resonances, cross section limits of hh production from a heavy Higgs boson decay are set as a function of the heavy Higgs boson mass. The observed (expected) limits range from 2.1 (1.1) pb at 260 GeV to 0.011 (0.018) pb at 1000 GeV. These results are interpreted in the context of two simplified scenarios of the Minimal Supersymmetric Standard Model.

Cultural circuits of climate change in U.K. broadsheet newspapers, 1985���2003

This article argues for a cultural perspective to be brought to bear on studies of climate change risk perception. Developing the ���circuit of culture��� model, the article maintains that the producers and consumers of media texts are jointly engaged in dynamic, meaning-making activities that are context-specific and that change over time. A critical discourse analysis of climate change based on a database of newspaper reports from three U.K. broadsheet papers over the period 1985���2003 is presented. This empirical study identifies three distinct circuits of climate change���1985���1990, 1991���1996, 1997���2003���which are characterized by different framings of risks associated with climate change. The article concludes that there is evidence of social learning as actors build on their experiences in relation to climate change science and policy making. Two important factors in shaping the U.K.���s broadsheet newspapers��� discourse on ���dangerous��� climate change emerge as the agency of top political figures and the dominant ideological standpoints in different newspapers.