2,122 research outputs found

    ZnO-Based Light-Emitting Diodes

    Get PDF

    Width of Radio-Loud and Radio-Quiet CMEs

    Full text link
    In the present paper we report on the difference in angular sizes between radio-loud and radio-quiet CMEs. For this purpose we compiled these two samples of events using Wind/WAVES and SOHO/LASCO observations obtained during 1996-2005. It is shown that the radio-loud CMEs are almost two times wider than the radio-quiet CMEs (considering expanding parts of CMEs). Furthermore we show that the radio-quiet CMEs have a narrow expanding bright part with a large extended diffusive structure. These results were obtained by measuring the CME widths in three different ways.Comment: Solar Physic, in pres

    Electrical switching and memory phenomena observed in redox-gradient dendrimer sandwich devices

    Full text link
    We report on the fabrication of dendrimer sandwich devices with electrical switching and memory properties. The storage media is consisted of a redox-gradient dendrimer layer sandwiched in organic barrier thin films. The dendrimer layer acts as potential well where redox-state changes and consequent electrical transitions of the embedded dendrimer molecules are expected to be effectively triggered and retained, respectively. Experimental results indicated that electrical switching could be reproducibly obtained in such dendrimer sandwiches upon a threshold bias voltage. After switching, the device conductivity could be increased more than three orders of magnitude, which can keep stable for several days in ambient conditions. Our work demonstrates the possibility of using solid-state redox-gradient dendrimer films as hopeful information storage media.Comment: 13 pages, 5 figures, 1 table, unpublished manuscrip

    Gutzwiller-Correlated Wave Functions: Application to Ferromagnetic Nickel

    Full text link
    Ferromagnetic Nickel is the most celebrated iron group metal with pronounced discrepancies between the experimental electronic properties and predictions of density functional theories. In this work, we show in detail that the recently developed multi-band Gutzwiller theory provides a very good description of the quasi-particle band structure of nickel. We obtain the correct exchange splittings and we reproduce the experimental Fermi-surface topology. The correct (111)-direction of the magnetic easy axis and the right order of magnitude of the magnetic anisotropy are found. Our theory also reproduces the experimentally observed change of the Fermi-surface topology when the magnetic moment is oriented along the (001)-axis. In addition to the numerical study, we give an analytical derivation for a much larger class of variational wave-functions than in previous investigations. In particular, we cover cases of superconductivity in multi-band lattice systems.Comment: 35 pages, 3 figure

    Tunneling of quantum rotobreathers

    Full text link
    We analyze the quantum properties of a system consisting of two nonlinearly coupled pendula. This non-integrable system exhibits two different symmetries: a permutational symmetry (permutation of the pendula) and another one related to the reversal of the total momentum of the system. Each of these symmetries is responsible for the existence of two kinds of quasi-degenerated states. At sufficiently high energy, pairs of symmetry-related states glue together to form quadruplets. We show that, starting from the anti-continuous limit, particular quadruplets allow us to construct quantum states whose properties are very similar to those of classical rotobreathers. By diagonalizing numerically the quantum Hamiltonian, we investigate their properties and show that such states are able to store the main part of the total energy on one of the pendula. Contrary to the classical situation, the coupling between pendula necessarily introduces a periodic exchange of energy between them with a frequency which is proportional to the energy splitting between quasi-degenerated states related to the permutation symmetry. This splitting may remain very small as the coupling strength increases and is a decreasing function of the pair energy. The energy may be therefore stored in one pendulum during a time period very long as compared to the inverse of the internal rotobreather frequency.Comment: 20 pages, 11 figures, REVTeX4 styl

    Two types of liposomal formulations improve the therapeutic ratio of prednisolone phosphate in a zebrafish model for inflammation

    Get PDF
    Glucocorticoids (GCs) are effective anti-inflammatory drugs, but their clinical use is limited by their side effects. Using liposomes to target GCs to inflammatory sites is a promising approach to improve their therapeutic ratio. We used zebrafish embryos to visualize the biodistribution of liposomes and to determine the anti-inflammatory and adverse effects of the GC prednisolone phosphate (PLP) encapsulated in these liposomes. Our results showed that PEGylated liposomes remained in circulation for long periods of time, whereas a novel type of liposomes (which we named AmbiMACs) selectively targeted macrophages. Upon laser wounding of the tail, both types of liposomes were shown to accumulate near the wounding site. Encapsulation of PLP in the PEGylated liposomes and AmbiMACs increased its potency to inhibit the inflammatory response. However, encapsulation of PLP in either type of liposome reduced its inhibitory effect on tissue regeneration, and encapsulation in PEGylated liposomes attenuated the activation of glucocorticoid-responsive gene expression throughout the body. Thus, by exploiting the unique possibilities of the zebrafish animal model to study the biodistribution as well as the anti-inflammatory and adverse effects of liposomal formulations of PLP, we showed that PEGylated liposomes and AmbiMACs increase the therapeutic ratio of this GC drug.Supramolecular & Biomaterials ChemistryAnimal science

    Partial Wave Analysis of J/ψγ(K+Kπ+π)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

    Full text link
    BES data on J/ψγ(K+Kπ+π)J/\psi \to \gamma (K^+K^-\pi^+\pi^-) are presented. The KKˉK^*\bar K^* contribution peaks strongly near threshold. It is fitted with a broad 0+0^{-+} resonance with mass M=1800±100M = 1800 \pm 100 MeV, width Γ=500±200\Gamma = 500 \pm 200 MeV. A broad 2++2^{++} resonance peaking at 2020 MeV is also required with width 500\sim 500 MeV. There is further evidence for a 2+2^{-+} component peaking at 2.55 GeV. The non-KKˉK^*\bar K^* contribution is close to phase space; it peaks at 2.6 GeV and is very different from KKˉK^{*}\bar{K^{*}}.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

    An embedded cohesive crack model for finite element analysis of quasi-brittle materials

    Full text link
    This paper presents a numerical implementation of the cohesive crack model for the anal-ysis of quasibrittle materials based on the strong discontinuity approach in the framework of the finite element method. A simple central force model is used for the stress versus crack opening curve. The additional degrees of freedom defining the crack opening are determined at the crack level, thus avoiding the need for performing a static condensation at the element level. The need for a tracking algorithm is avoided by using a consistent pro-cedure for the selection of the separated nodes. Such a model is then implemented into a commercial program by means of a user subroutine, consequently being contrasted with the experimental results. The model takes into account the anisotropy of the material. Numerical simulations of well-known experiments are presented to show the ability of the proposed model to simulate the fracture of quasibrittle materials such as mortar, concrete and masonry
    corecore