777 research outputs found

    Radiation zeros in weak boson production processes at hadron colliders

    Get PDF
    The Standard Model amplitudes for processes where one or more gauge bosons are emitted exhibit zeros in the angular distributions. The theoretical and experimental aspects of these radiation amplitude zeros are reviewed and some recent results are discussed. In particular, the zeros of the WZγWZ\gamma and WZZWZZ production amplitudes are analyzed. It is briefly explained how radiation zeros can be used to test the SM.Comment: Talk given at 22nd Annual MRST (Montreal-Rochester-Syracuse-Toronto) Meeting: Conference on Theoretical High-Energy Physics, Rochester, New York, 8-9 May 200

    Organic semiconductor-based photonic crystals for solar cell arrays: band gap and optical properties

    Get PDF
    Cataloged from PDF version of article.Photonic crystals (PCs) hold great potential for designing new optical devices because of the possibility of the manipulation of light with PCs. There has been an increase in research on tuning the optical properties of PCs to design devices. We design organic semiconductor-based PC structures and calculate optical properties using the plane wave expansion method and finite-difference time-domain method in an air background for a hexagonal lattice. We showed the possibility of the solar cell arrays for a 2D PC cavity on an organic semiconductor base infiltrated with a nematic liquid crystal. E7 type has been used as a nematic liquid crystal and 4,4-Bis[4-(diphenylamino) styryl]biphenyl as an organic semiconductor material

    Optical properties of metamaterial-based devices modulated by a liquid crystal

    Get PDF
    Cataloged from PDF version of article.Due to the fact that it is possible to manipulate light with photonic crystals (PCs), PCs hold a great potential for designing new optical devices. There has been an increase in research on tuning the optical properties of PCs to design devices. We presented a numerical study of optical properties of metamaterial-based devices by liquid crystal infiltration. The plane wave expansion method and finite-difference time-domain method for both TE and TM modes revealed optical properties in photonic crystal structures in an air background for a square lattice. E7 type has been used as a nematic liquid crystal and SrTiO3 as a ferroelectric material. We showed the possibility of the metamaterials for a two-dimensional photonic crystal cavity on a ferroelectric base infiltrated with a nematic liquid crystal

    Radiolysis and Photolysis of Water Solutions of Phenol

    Get PDF
    The kinetics of phenol transformation products. Radiolysis and photolysis of water solutions. Speed increase effects during phenol transformation are determined when molecular oxygen is added. Here we assess the thermo dynamical parameters od basic reactions and limiting stage of process. Courses of reaction and new mechanisms of relevant radiolytical and photolytical processes are identified

    ALTICORE: an initiative for coastal altimetry

    Full text link
    ALTICORE (value-added ALTImetry for COastal REgions) is an international initiative whose main objective is to encourage the operational use of altimetry over coastal areas, by improving the quality and availability of coastal altimetry data. The ALTICORE proposal has recently been submitted for funding to the INTAS scheme (www.intas.be) by a consortium of partners from Italy, France, UK, Russia and Azerbaijan. ALTICORE is also meant as a contribution to the ongoing International Altimeter Service effort. In this work we will describe the anticipated project stages, namely: 1) improvement of the most widely distributed, 1 Hz, data by analyzing the corrective terms and providing the best solutions, including those derived from appropriate local modelling; 2) development of a set of algorithms to automate quality control and gap-filling functions for the coastal regions; 3) development of testing strategies to ensure a thorough validation of the data. The improved products will be delivered to ALTICORE users via Grid-compliant technology; this makes it easier to integrate the local data holdings, allows access from a range of services, e.g. directly into model assimilation or GIS systems and should therefore facilitate a widespread and complete assessment of the 1Hz data performance and limitations. We will also outline the design and implementation of the Grid-compliant system for efficient access to distributed archives of data; this consists of regional data centres, each having primary responsibility for regional archives, local corrections and quality control, and operating a set of web-services allowing access to the full functionality of data extraction. We will conclude by discussing a follow-on phase of the project; this will investigate further improvements on the processing strategy, including the use of higher frequency (10 or 20 Hz) data. Phenomena happen at smaller spatial scales near the coast, so this approach is necessary to match the required resolution. The whole project will hopefully promote the 15-year sea surface height from altimetry to the rank of operational record for the coastal areas

    Ferroelectric Based Photonic Crystal Cavity by Liquid Crystal Infiltration

    Get PDF
    Cataloged from PDF version of article.A novel type of two-dimensional photonic crystal is investigated for it optical properties as a core-shell-type ferroelectric nanorod infiltrated with nematic liquid crystals. Using the plane wave expansion method and finite-difference time-domain method, the photonic crystal structure, which is composed of a photonic crystal in a core-shell-type ferroelectric nanorod, is designed for the square lattice and the hexagonal lattice. It has been used 5CB as a photonic crystal core, and LiNbO3 as a ferroelectric material. The photonic crystal with a core-shell-type LiNbO3 nanorod infiltrated with nematic liquid crystals is compared with the photonic crystal with solid LiNbO3 rods and the photonic crystal with hollow LiNbO3 rods

    The indisputable value of ultrasound diagnostics in acute small bowel obstruction

    Get PDF
    The use of ultrasound in the diagnosis of acute small bowel obstruction is justified from a tactical point of view, since it is not delayed in time, does not weigh down the patient's condition, has sufficient information and does not carry radiation load. Due to its safety and ease of use, this technique can be used repeatedly in the process of conservative treatment to determine further treatment tactics

    Opening of a pseudogap in a quasi-two dimensional superconductor due to critical thermal fluctuations

    Get PDF
    We examine the role of the anisotropy of superconducting critical thermal fluctuations in the opening of a pseudogap in a quasi-two dimensional superconductor such as a cuprate-oxide high-temperature superconductor. When the anisotropy between planes and their perpendicular axis is large enough and its superconducting critical temperature T_c is high enough, the fluctuations are much developed in its critical region so that lifetime widths of quasiparticles are large and the energy dependence of the selfenergy deviates from that of Landau's normal Fermi liquids. A pseudogap opens in such a critical region because quasiparticle spectra around the chemical potential are swept away due to the large lifetime widths. The pseudogap never smoothly evolves into a superconducting gap; it starts to open at a temperature higher than T_c while the superconducting gap starts to open just at T_c. When T_c is rather low but the ratio of varepsilon_G(0)/k_BT_c, with varepsilon_G(0) the superconducting gap at T=0K and k_B the Boltzmann constant, is much larger than a value about 4 according to the mean-field theory, the pseudogap must be closing as temperature T approaches to the low T_c because thermal fluctuations become less developed as T decreases. Critical thermal fluctuations cannot cause the opening of a prominent pseudogap in an almost isotropic three dimensional superconductor, even if its T_c is high.Comment: 25 pages, 5 figures (14 subfigures
    corecore