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391.
We explain how multiplicative bundle gerbes over a compact, connected and simple Lie group G lead to a certain fusion category of equivariant bundle gerbe modules given by pre-quantizable Hamiltonian LG-manifolds arising from Alekseev-Malkin-Meinrenken’s quasi-Hamiltonian G-spaces. The motivation comes from string theory namely, by generalising the notion of D-branes in G to allow subsets of G that are the image of a G-valued moment map we can define a ‘fusion of D-branes’ and a map to the Verlinde ring of the loop group of G which preserves the product structure. The idea is suggested by the theorem of Freed-Hopkins-Teleman. The case where G is not simply connected is studied carefully in terms of equivariant bundle gerbe modules for multiplicative bundle gerbes. 相似文献
392.
Sustained resonance in a linear oscillator is achievable with a drive whose constant frequency matches the resonant frequency of the oscillator. But in oscillators with nonlinear restoring forces such as the pendulum, Duffing and Duffing-Van der Pol oscillator, the resonant frequency changes as the amplitude changes, so a constant frequency drive results in a beat oscillation instead of sustained resonance. Duffing-type nonlinear oscillators can be driven into sustained resonance, called autoresonance, when the drive frequency is swept in time to match the changing resonant frequency of the oscillator. We find that near-optimal drive linear sweep rates for autoresonance can be estimated from the beat oscillation resulting from constant frequency excitation. Specifically, a least squares estimate of the Teager-Kaiser instantaneous frequency versus time for the beat response to a stationary drive provides a near-optimal estimate of the nonstationary drive linear sweep rate needed to sustain resonance in the pendulum, Duffing and Duffing-Van der Pol oscillators. We confirm these predictions with model-based numerical simulations. An advantage of the beat method of estimating optimal drive sweep rates for maximal autoresonant response is that no model is required so experimentally generated beat oscillation data can be used for systems where no model is available. 相似文献
393.
Adcox K Adler SS Ajitanand NN Akiba Y Alexander J Aphecetche L Arai Y Aronson SH Averbeck R Awes TC Barish KN Barnes PD Barrette J Bassalleck B Bathe S Baublis V Bazilevsky A Belikov S Bellaiche FG Belyaev ST Bennett MJ Berdnikov Y Botelho S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy J Butsyk S Carey TA Chand P Chang J Chang WC Chavez LL Chernichenko S Chi CY Chiba J Chiu M Choudhury RK Christ T Chujo T Chung MS Chung P Cianciolo V Cole BA D'Enterria DG 《Physical review letters》2002,89(21):212301
Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c. 相似文献
394.
An experimental methodology is proposed in which localized convective boiling heat transfer coefficients inside the tubes of compact evaporators are determined by testing of full evaporator cores. The proposed technique makes use of a special test system having two main flow circuits. One of these flow loops is a conventional vapor compression system, which provides a steady, low-quality, two-phase flow of refrigerant to the tube side of the evaporator. The second primary flow loop provides a steady flow of the vapor of a second working fluid, which condenses on the finned side of the evaporator. Measured data from this system are analyzed using an iterative scheme. Trends in the variation of the refrigerant-side heat transfer coefficient determined by this method throughout a typical evaporator core are described, and the differences and similarities relative to previously published results for single round tubes are discussed. 相似文献
395.
R. Carey P. A. O''Rourke B. W. J. Thomas 《Journal of magnetism and magnetic materials》1985,50(3):335-338
Thin films of Nd-Fe prepared by rf sputtering are shown to exhibit marked perpendicular anisotropy. Hysteresis loops with a sqaureness ratio of essentially 1.0 with large coercivities and significant polar Kerr rotations are reported for films with 60 at% Nd. 相似文献
396.
397.
A. L. Carey 《Acta Appl Math》1983,1(4):321-331
This paper surveys recent work on representations of infinite dimensional groups and the connection with quantum field theory. 相似文献
398.
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