21,941 research outputs found

    Electromechanical tuning of vertically-coupled photonic crystal nanobeams

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    We present the design, the fabrication and the characterization of a tunable one-dimensional (1D) photonic crystal cavity (PCC) etched on two vertically-coupled GaAs nanobeams. A novel fabrication method which prevents their adhesion under capillary forces is introduced. We discuss a design to increase the flexibility of the structure and we demonstrate a large reversible and controllable electromechanical wavelength tuning (> 15 nm) of the cavity modes.Comment: 11 pages, 4 figure

    Measurements of the Rate Capability of Various Resistive Plate Chambers

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    Resistive Plate Chambers (RPCs) exhibit a significant loss of efficiency for the detection of particles, when subjected to high particle fluxes. This rate limitation is related to the usually high resistivity of the resistive plates used in their construction. This paper reports on measurements of the performance of three different glass RPC designs featuring a different total resistance of the resistive plates. The measurements were performed with 120 GeV protons at varying beam intensitie

    Fermi surface topology and low-lying quasiparticle structure of magnetically ordered Fe1+xTe

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    We report the first photoemission study of Fe1+xTe - the host compound of the newly discovered iron-chalcogenide superconductors. Our results reveal a pair of nearly electron- hole compensated Fermi pockets, strong Fermi velocity renormalization and an absence of a spin-density-wave gap. A shadow hole pocket is observed at the "X"-point of the Brillouin zone which is consistent with a long-range ordered magneto-structural groundstate. No signature of Fermi surface nesting instability associated with Q= pi(1/2, 1/2) is observed. Our results collectively reveal that the Fe1+xTe series is dramatically different from the undoped phases of the high Tc pnictides and likely harbor unusual mechanism for superconductivity and quantum magnetic order.Comment: 5 pages, 4 Figures; Submitted to Phys. Rev. Lett. (2009

    Moderate deviation principle for ergodic Markov chain. Lipschitz summands

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    For 1/2<α<1{1/2}<\alpha<1, we propose the MDP analysis for family Snα=1nαi=1nH(Xi1),n1, S^\alpha_n=\frac{1}{n^\alpha}\sum_{i=1}^nH(X_{i-1}), n\ge 1, where (Xn)n0(X_n)_{n\ge 0} be a homogeneous ergodic Markov chain, XnRdX_n\in \mathbb{R}^d, when the spectrum of operator PxP_x is continuous. The vector-valued function HH is not assumed to be bounded but the Lipschitz continuity of HH is required. The main helpful tools in our approach are Poisson's equation and Stochastic Exponential; the first enables to replace the original family by 1nαMn\frac{1}{n^\alpha}M_n with a martingale MnM_n while the second to avoid the direct Laplace transform analysis

    Prediction of Postchemotherapy Ovarian Function Using Markers of Ovarian Reserve

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140040/1/onco0068.pd

    RIS-Assisted Integrated Sensing and Backscatter Communications for Future IoT Networks

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    Reconfigurable intelligent surface (RIS), by intelligently manipulating the incident waveform, offers a spectral and energy efficient capability for improving sensing and communication performance. In this article, we introduce a novel concept of RIS-assisted integrated sensing and backscatter communication (ISABC) system, by introducing RIS as either helper or transceiver to resolve the energy constraint of devices in internet of things (IoT) network and enable non line-of-sight (NLoS) sensing. We first introduce the RIS-assisted ISABC framework, including the system architecture and realization of RIS. Three potential applications are then discussed, with the analysis on their requirements. The research on several critical techniques for the RIS-assisted ISABC system is then discussed. Finally, we provide our vision of the challenges and future research directions to facilitate the development of the RIS-assisted ISABC systems

    Cyclic cosmology from Lagrange-multiplier modified gravity

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    We investigate cyclic and singularity-free evolutions in a universe governed by Lagrange-multiplier modified gravity, either in scalar-field cosmology, as well as in f(R)f(R) one. In the scalar case, cyclicity can be induced by a suitably reconstructed simple potential, and the matter content of the universe can be successfully incorporated. In the case of f(R)f(R)-gravity, cyclicity can be induced by a suitable reconstructed second function f2(R)f_2(R) of a very simple form, however the matter evolution cannot be analytically handled. Furthermore, we study the evolution of cosmological perturbations for the two scenarios. For the scalar case the system possesses no wavelike modes due to a dust-like sound speed, while for the f(R)f(R) case there exist an oscillation mode of perturbations which indicates a dynamical degree of freedom. Both scenarios allow for stable parameter spaces of cosmological perturbations through the bouncing point.Comment: 8 pages, 3 figures, references added, accepted for publicatio
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