7,494 research outputs found

    RTP control protocol (RTCP) extended report (XR) block for independent reporting of burst/fgp discard metrics

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    This document defines an RTP Control Protocol (RTCP) Extended Report (XR) block that allows the reporting of burst/gap discard metrics independently of the burst/gap loss metrics for use in a range of RTP applications

    Orbital-spin order and the origin of structural distortion in MgTi2_2O4_4

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    We analyze electronic, magnetic, and structural properties of the spinel compound MgTi2_2O4_4 using the local density approximation+U method. We show how MgTi2_2O4_4 undergoes to a canted orbital-spin ordered state, where charge, spin and orbital degrees of freedom are frozen in a geometrically frustrated network by electron interactions. In our picture orbital order stabilize the magnetic ground state and controls the degree of structural distortions. The latter is dynamically derived from the cubic structure in the correlated LDA+U potential. Our ground-state theory provides a consistent picture for the dimerized phase of MgTi2_2O4_4, and might be applicable to frustrated materials in general.Comment: 6 pages, 6 figure

    Single polymer dynamics: coil-stretch transition in a random flow

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    By quantitative studies of statistics of polymer stretching in a random flow and of a flow field we demonstrate that the stretching of polymer molecules in a 3D random flow occurs rather sharply via the coil-stretch transition at the value of the criterion close to theoretically predicted.Comment: 4 pages, 5 figure

    Design guidelines for use of adhesives and organic coatings in hybrid microcircuits

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    A study was conducted to investigate the reliability of organic adhesives in hybrid microcircuits. The objectives were twofold: (1) to identify and investigate problem areas that could result from the use of organic adhesives and (2) to develop evaluation tests to quantify the extent to which these problems occur for commercially available adhesives. Efforts were focused on electrically conductive adhesives. Also, a study was made to evaluate selected organic coatings for contamination protection for hybrid microcircuits

    Particle phenomenology on noncommutative spacetime

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    We introduce particle phenomenology on the noncommutative spacetime called the Groenewold-Moyal plane. The length scale of spcetime noncommutativity is constrained from the CPT violation measurements in K0Kˉ0K^{0}-\bar{K}^{0} system and g2g-2 difference of μ+μ\mu^+ - \mu^-. The K0Kˉ0K^{0}-\bar{K}^{0} system provides an upper bound on the length scale of spacetime noncommutativity of the order of 1032m10^{-32} \textrm{m}, corresponding to a lower energy bound EE of the order of E1016GeVE \gtrsim 10^{16}\textrm{GeV}. The g2g-2 difference of μ+μ\mu^+ - \mu^- constrains the noncommutativity length scale to be of the order of 1020m10^{-20} \textrm{m}, corresponding to a lower energy bound EE of the order of E103GeVE \gtrsim 10^{3}\textrm{GeV}. We also present the phenomenology of the electromagnetic interaction of electrons and nucleons at the tree level in the noncommutative spacetime. We show that the distributions of charge and magnetization of nucleons are affected by spacetime noncommutativity. The analytic properties of electromagnetic form factors are also changed and it may give rise to interesting experimental signals.Comment: 10 pages, 3 figures. Published versio

    Efimov states and their Fano resonances in a neutron-rich nucleus

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    Asymmetric resonances in elastic n+19^{19}C scattering are attributed to Efimov states of such neutron-rich nuclei, that is, three-body bound states of the n+n+18^{18}C system when none of the pairs is bound or some of them only weakly bound. By fitting to the general resonance shape described by Fano, we extract resonance position, width, and the "Fano profile index". While Efimov states have been discussed extensively in many areas of physics, there is only one very recent experimental observation in trimers of cesium atoms. The conjunction that we present of the Efimov and Fano phenomena may lead to experimental realization in nuclei.Comment: 4 double-column pages, 3 figure

    Curvature Radiation by Ultrarelativistic Protons

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    We study pion curvature radiation by a proton, i.e. pion emission by a proton moving along a curved trajectory. We suggest an approximate semiclassical solution and the exact solution for which we assume that a proton moves in a fictitious magnetic field with the Larmor radius equal to the curvature radius of the real trajectory. As possible application we consider the pion radiation by ultrahigh energy protons moving along curved magnetic field lines. Such situation can occur in the magnetosphere of a young pulsar, in the magnetosphere of the accretion disk around a black hole, and in the vicinity of a superconducting cosmic string. The decay products of these pions, such as high energy photons or neutrinos, can give the observable consequences of the considered mechanism.Comment: 5 pages, revtex, to appear in Physics Letters

    Flight Tests, Performances and Flight Certification of a Twin-Engine Light Aircraft

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    This paper deals with flight test activities performed on P2006T, a twin-engine light aircraft recently designed and produced by Tecnam. Research activities and flight tests have been conducted during the flight certification of P2006T for the normal category under CS-23. All the acquired data and flight results presented have been focused on both aircraft certification and on aircraft performances, stability and flight qualities measurement. The data have been acquired through a light, accurate and reliable flight instrumentation available at DIAS (Department of Aerospace Engineering). Some flight data about aircraft leveled speed, stall speed, climb characteristics and ground performances (take-off and landing) will be presented. After preliminary flight tests, winglets have been designed and added to the final configuration in order to obtain good climb performances also in OEI (One Engine Inoperative) conditions. Accurate stall tests have been performed in all configurations and influence of both entry-rate and load factor on stall speed have been highlighted. Excellent ground performances have been measured with short take-off and landing distances compared with similar airplanes. All measured flight performances can be considered very good for this aircraft category and have been used to demonstrate aircraft safety and to obtain CS23 certification

    Electronic states and magnetic excitations in LiV2O4: Exact diagonalization study

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    Motivated by recent inelastic neutron scattering experiment we examine magnetic properties of LiV2O4. We consider a model which describes the half-filled localized A1g spins interacting via frustrated antiferromagnetic Heisenberg exchange and coupled by local Hund's interaction with the 1/8-filled itinerant Eg band, and study it within an exact diagonalization scheme. In the present study we limited the analysis to the case of the cluster of two isolated tetrahedrons. We obtained that both the ground state structure and low-lying excitations depend strongly on the value of the Hund's coupling which favors the triplet states. With increasing temperature the triplet states become more and more populated which results in the formation of non-zero residual magnetic moment. We present the temperature dependence of calculated magnetic moment and of the spin-spin correlation functions at different values of Hund's coupling and compare them with the experimental results.Comment: 7 pages. 6 eps figure
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