6,796 research outputs found
Mixed harmonic azimuthal correlations in Pb--Pb collisions at \sqrt{s_{NN}}=2.76TeV measured with the ALICE experiment at the LHC
Mixed harmonic charge dependent azimuthal correlations at mid-rapidity in
Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV were measured with the ALICE
detector at the LHC. A clear charge dependence for a series of correlations is
observed both via the multi-particle cumulant and the event plane methods.
Implications from these measurements for the possible effects of local parity
violation in QCD and for models which incorporate azimuthal anisotropic flow
and "effective" local charge conservation on the kinetic freeze-out surface are
discussed.Comment: 6 pages, 5 figures, proceedings of International symposium on
multiparticle dynamics 2012 (ISMD2012
Survival Rates of Planets in Open Clusters: the Pleiades, Hyades, and Praesepe clusters
In clustered environments, stellar encounters can liberate planets from their
host stars via close encounters. Although the detection probability of planets
suggests that the planet population in open clusters resembles that in the
field, only a few dozen planet-hosting stars have been discovered in open
clusters. We explore the survival rates of planets against stellar encounters
in open clusters similar to the Pleiades, Hyades, and Praesepe and embedded
clusters. We performed a series of N-body simulations of high-density and
low-density open clusters, open clusters that grow via mergers of subclusters,
and embedded clusters. We semi-analytically calculated the survival rate of
planets in star clusters up to 1Gyr using relative velocities, masses, and
impact parameters of intruding stars. Less than 1.5% of close-in planets within
1 AU and at most 7% of planets with 1-10 AU are ejected by stellar encounters
in clustered environments after the dynamical evolution of star clusters. If a
planet population from 0.01-100 AU in an open cluster initially follows the
probability distribution function of exoplanets with semi-major axis ()
between 0.03-3 AU in the field discovered by RV surveys, the PDF of surviving
planets beyond ~10 AU in open clusters can be slightly modified to . The production rate of free-floating planets (FFPs) per star is
0.0096-0.18, where we have assumed that all the stars initially have one giant
planet with a mass of 1--13 MJ in a circular orbit. The expected frequency of
FFPs is compatible with the upper limit on that of FFPs indicated by recent
microlensing surveys. Our survival rates of planets in open clusters suggest
that planets within 10 AU around FGKM-type stars are rich in relatively-young
(<~10-100 Myr for open clusters and ~1-10 Myr for embedded clusters), less
massive open clusters, which are promising targets for planet searches.Comment: 23 pages, 15 figures, A&A accepte
Optimal control design for robust fuzzy friction compensation in a robot joint
This paper presents a methodology for the compensation of nonlinear friction in a robot joint structure based on a fuzzy local modeling technique. To enhance the tracking performance of the robot joint, a dynamic model is derived from the local physical properties of friction. The model is the basis of a precompensator taking into account the dynamics of the overall corrected system by means of a minor loop. The proposed structure does not claim to faithfully reproduce complex phenomena driven by friction. However, the linearity of the local models simplifies the design and implementation of the observer, and its estimation capabilities are improved by the nonlinear integral gain. The controller can then be robustly synthesized using linear matrix inequalities to cancel the effects of inexact friction compensation. Experimental tests conducted on a robot joint with a high level of friction demonstrate the effectiveness of the proposed fuzzy observer-based control strategy for tracking system trajectories when operating in zero-velocity regions and during motion reversals
Direct yaw-moment control of an in-wheel-motored electric vehicle based on body slip angle fuzzy observer
A stabilizing observer-based control algorithm for an in-wheel-motored vehicle is proposed, which generates direct yaw moment to compensate for the state deviations. The control scheme is based on a fuzzy rule-based body slip angle (beta) observer. In the design strategy of the fuzzy observer, the vehicle dynamics is represented by Takagi-Sugeno-like fuzzy models. Initially, local equivalent vehicle models are built using the linear approximations of vehicle dynamics for low and high lateral acceleration operating regimes, respectively. The optimal beta observer is then designed for each local model using Kalman filter theory. Finally, local observers are combined to form the overall control system by using fuzzy rules. These fuzzy rules represent the qualitative relationships among the variables associated with the nonlinear and uncertain nature of vehicle dynamics, such as tire force saturation and the influence of road adherence. An adaptation mechanism for the fuzzy membership functions has been incorporated to improve the accuracy and performance of the system. The effectiveness of this design approach has been demonstrated in simulations and in a real-time experimental settin
Statistical mechanics and large-scale velocity fluctuations of turbulence
Turbulence exhibits significant velocity fluctuations even if the scale is
much larger than the scale of the energy supply. Since any spatial correlation
is negligible, these large-scale fluctuations have many degrees of freedom and
are thereby analogous to thermal fluctuations studied in the statistical
mechanics. By using this analogy, we describe the large-scale fluctuations of
turbulence in a formalism that has the same mathematical structure as used for
canonical ensembles in the statistical mechanics. The formalism yields a
universal law for the energy distribution of the fluctuations, which is
confirmed with experiments of a variety of turbulent flows. Thus, through the
large-scale fluctuations, turbulence is related to the statistical mechanics.Comment: 7 pages, accepted by Physics of Fluids (see http://pof.aip.org/
Non-compact Mirror Bundles and (0,2) Liouville Theories
We study (0,2) deformations of N=2 Liouville field theory and its mirror
duality. A gauged linear sigma model construction of the ultraviolet theory
connects (0,2) deformations of Liouville field theory and (0,2) deformations of
N=2 SL(2,R)/U(1) coset model as a mirror duality. Our duality proposal from the
gauged linear sigma model completely agrees with the exact CFT analysis. In the
context of heterotic string compactifications, the deformation corresponds to
the introduction of a non-trivial gauge bundle. This non-compact
Landau-Ginzburg construction yields a novel way to study the gauge bundle
moduli for non-compact Calabi-Yau manifolds.Comment: 34 page
Non-equilibrium and non-linear stationary state in thermoelectric materials
Efficiency of thermoelectric materials is characterized by the figure of
merit Z. Z has been believed to be a peculiar material constant. However, the
accurate measurements in the present work reveal that Z has large size
dependence and a non-linear temperature distribution appears as stationary
state in the thermoelectric material. The observation of these phenomena is
achieved by the Harman method. This method is the most appropriate way to
investigate the thermoelectric properties because the dc and ac resistances are
measured by the same electrode configuration. We describe the anomalous
thermoelectric properties observed in mainly (Bi,Sb)2Te3 by the Harman method
and then insist that Z is not the peculiar material constant but must be
defined as the physical quantity dependent of the size and the position in the
material.Comment: 9 pages, 4 figures. submitted to Applied Physics Lette
Effects of cAMP on the composition of berry juice in Muscat Bailey A
In Muscat Bailey A, the increases of organic acids due to cAMP prebloom application 3 weeks before final harvest were accompanied by increases of glucose and fructose, though these increments compared with control diminished toward full maturity.
Der Einfluß von cyclischem Adenosin-3' ,5' -monophosphat auf die Zusammensetzung des Beerensaftes bei Muscat Bailey A
Wurden die Infloreszenzen der Rebsorte Muscat Bailey A (Vitis labrusca L. x V. vinifera L.) vor der Blüte mit cAMP behandelt, so war 3 Wochen vor der vollen Reife ein Anstieg des Säuregehaltes und ebenso der Glucose- und Fructosekonzentration zu verzeichnen; gegen Ende der Reifephase waren die Unterschiede im Glucose- und Fructosegehalt behandelter und unbehandelter Beeren allerdings ziemlich verwischt
Increase of the acid contents in grape berries by treatment with cAMP
cAMP prebloom application to flower clusters of the grapevine variety Delaware (Vitis labruscana BAILEY) raised the content of organic acids in the repening berries. The total content of amino acids in the juice was raised by postbloom application, alanine, arginine and γ-aminobutyric acid being increased, whereas tyrosine was decreased.
Zunahme des Säuregehaltes reifender Traubenbeeren durch Behandlung mit cyclischemAdenosin-3',5' -monophosphat
Bei der Rebsorte Delaware wurde durch Behandlung der Infloreszenzen mit cAMP vor der Blüte der Gehalt des Beerensaftes an organischen Säuren erhöht.Durch cAMP-Behandlung nach der Blüte wurde der Gesamtgehalt der Aminosäuren gesteigert, wobei Alanin, Arginin und γ-Aminobuttersäure zunahmen, während die Tyrosinkonzentration verringert war.
 
Induction of tumour blood flow stasis and necrosis: a new function for epinephrine similar to that of combretastatin A-4 derivative AVE8062 (AC7700)
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