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71.
72.
73.
We study, theoretically and experimentally, the evolution of patterns in a passive nonlinear cavity that is longer than the coherence length of the light circulating in it. The patterns exhibit spatial line narrowing as the feedback is increased, resembling the line narrowing in lasers. 相似文献
74.
Ph. Gavillet C. Dionisi A. Gurtu R.J. Hemingway M.J. Losty J.C. Marin M. Mazzucato L. Montanet E. Pagiola R. Blokzijl B. Jongejans J.C. Kluyver G.G.G. Massaro J.J. Engelen J.S.M. Vergeest M. Zralek B. Foster P. Grossmann J. Wells 《Physics letters. [Part B]》1978,78(1):158-161
The backward production of the B(1235) meson is studied in the reaction K?p→Σ?π+ω. This reaction is observed in the final state Σ?π+π+π?π0. A π+ω mass enhancement is visible in the region of the B meson for events with small |u|K? →Σ?) squared four-momentum transfer. The properties of the enhancement agree with those of the B meson. The cross section for K?p→Σ?B+ at incident K? momentum is (3.2 ± 0.5) μb. The backward production of the B meson is compared with similar baryon exchange productions of the A1 and C(Q1) axial vector mesons observed in the same experiment. 相似文献
75.
76.
R.J. Hemingway R. Armenteros C. Dionisi Ph. Gavillet A. Gurtu S.O. Holmgren M.J. Losty J.C. Marin M. Mazzucato L. Montanet M. Banting R. Blokzijl A.J. De Groot B. Jongejans J.C. Kluyver W.M. Van Leeuwen G.G.G. Massaro J. Wells 《Nuclear Physics B》1978,142(3):205-219
Forty events have been observed in a large (133 events/βb) experiment at 4.2 GeV/c incident K? momentum. Thirty nine of the events come from the three-body reaction . The is mainly produced in the forward hemisphere (direction of the incident K?). The lifetime is measured to be τ = (0.75 +0.14?0.11 × 10?10 sec substantially less than the Particle Data Group value of (1.3 ?0.3+0.2) × 10?10 sec. The mass is determined to be 1671.7 ± 0.6 MeV, in good agreement with other determinations. The decay asymmetry parameter α (for the decay mode ) is found to be ?0.2 ± 0.4. 相似文献
77.
Marin Coldea Natalia Dihoiu Iuliu Pop 《Journal of Physics and Chemistry of Solids》1981,42(7):563-565
27Al Knight shifts vs temperature and magnetic susceptibility for the intermetallic compounds Gd2Ni17?xAlx (x = 17; 16.2; 16; 15) are presented. The results are discussed in terms of the uniform polarization model fo the conduction electrons by the 4f and 3d spins localized on the Gd and Ni ions. The phenomenological exchange constants Jsf and Jsd range between ?1.80×10?3 and 1.19×10?3 eV and ?0.63×10?3 and ?0.52×10?3 eV, respectively. 相似文献
78.
Yaouanc A de Réotier PD Glazkov V Marin C Bonville P Hodges JA Gubbens PC Sakarya S Baines C 《Physical review letters》2005,95(4):047203
Using muon-spin-relaxation measurements we show that the pyrochlore compound Gd(2)Ti(2)O(7), in its magnetically ordered phase below approximately 1 K, displays persistent spin dynamics down to temperatures as low as 20 mK. The characteristics of the induced muon relaxation can be accounted for by a scattering process involving two magnetic excitations, with a density of states characterized by an upturn at low energy and a small gap depending linearly on the temperature. We propose that such a density of states is a generic feature of geometrically frustrated magnetic materials. 相似文献
79.
Baggio L Bignotto M Bonaldi M Cerdonio M Conti L De Rosa M Falferi P Fortini P Inguscio M Liguori N Marin F Mezzena R Mion A Ortolan A Prodi GA Poggi S Salemi F Soranzo G Taffarello L Vedovato G Vinante A Vitale S Zendri JP;AURIGA Collaboration 《Physical review letters》2005,95(8):081103
At the time when the giant flare of SGR1806-20 occurred, the AURIGA "bar" gravitational-wave (GW) detector was on the air with a noise performance close to stationary Gaussian. This allows us to set relevant upper limits, at a number of frequencies in the vicinities of 900 Hz, on the amplitude of the damped GW wave trains, which, according to current models, could have been emitted, due to the excitation of normal modes of the star associated with the peak in x-ray luminosity. 相似文献
80.
Giampaolo?Liuzzi Stefano?LucidiEmail author Veronica?Piccialli Antonello?Sotgiu 《Mathematical Programming》2004,101(2):339-364
In this paper we are concerned with the design of a small low-cost, low-field multipolar magnet for Magnetic Resonance Imaging with a high field uniformity. By introducing appropriate variables, the considered design problem is converted into a global optimization one. This latter problem is solved by means of a new derivative free global optimization method which is a distributed multi-start type algorithm controlled by means of a simulated annealing criterion. In particular, the proposed method employs, as local search engine, a derivative free procedure. Under reasonable assumptions, we prove that this local algorithm is attracted by global minimum points. Additionally, we show that the simulated annealing strategy is able to produce a suitable starting point in a finite number of steps with probability one.This work was supported by CNR/MIUR Research Program Metodi e sistemi di supporto alle decisioni, Rome, Italy.Mathematics Subject Classification (1991):65K05, 62K05, 90C56 相似文献