7,583 research outputs found
RTP control protocol (RTCP) extended report (XR) block for independent reporting of burst/fgp discard metrics
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 MgTiO
We analyze electronic, magnetic, and structural properties of the spinel
compound MgTiO using the local density approximation+U method. We show
how MgTiO 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 MgTiO, and might be applicable to
frustrated materials in general.Comment: 6 pages, 6 figure
Single polymer dynamics: coil-stretch transition in a random flow
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
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
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 system
and difference of . The system
provides an upper bound on the length scale of spacetime noncommutativity of
the order of , corresponding to a lower energy bound
of the order of . The difference of constrains the noncommutativity length scale to be of the order of
, corresponding to a lower energy bound of the order
of .
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
Asymmetric resonances in elastic n+C scattering are attributed to
Efimov states of such neutron-rich nuclei, that is, three-body bound states of
the n+n+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
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
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
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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