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81.
R. Arnaldi R. Averbeck K. Banicz J. Castor B. Chaurand C. Cicalo A. Colla P. Cortese S. Damjanovic A. David A. De Falco A. Devaux A. Drees L. Ducroux H. En’yo A. Ferretti M. Floris A. Foerster P. Force N. Guettet A. Guichard H. Gulkanian J. Heuser M. Keil L. Kluberg J. Lozano C. Lourenço F. Manso A. Masoni P. Martins A. Neves H. Ohnishi C. Oppedisano P. Parracho P. Pillot G. Puddu E. Radermacher P. Ramalhete P. Rosinsky E. Scomparin J. Seixas S. Serci R. Shahoyan P. Sonderegger H.J. Specht R. Tieulent G. Usai R. Veenhof H.K. Wöhri 《The European Physical Journal C - Particles and Fields》2007,49(1):235-241
The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158 A GeV In–In collisions. A strong excess of pairs
is observed above the yield expected from neutral meson decays. The unprecedented sample size close to 400000 events and the
good mass resolution of about 2% made it possible to isolate the excess by subtraction of the decay sources. The shape of
the resulting mass spectrum shows some non-trivial centrality dependence, but is largely consistent with a dominant contribution
from π+π-→ϱ→μ+μ- annihilation. The associated ϱ spectral function exhibits considerable broadening, but essentially no shift in mass. The
pT-differential mass spectra show the excess to be much stronger at low pT than at high pT. The results are compared to theoretical model predictions; they tend to rule out models linking hadron masses directly to
the chiral condensate.
PACS 25.75.-q; 12.38.Mh; 13.85.Qk 相似文献
82.
83.
Carlo Carlini Valentina De Luise Anna Maria Raspolli Galletti Glauco Sbrana 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):200-206
Novel catalytic systems, prepared in situ by the oxidative addition of 8‐hydroxyquinoline ligands to bis(1,5‐cyclooctadiene)nickel(0) and activated by methylaluminoxane, were studied in ethylene polymerization. When 8‐hydroxyquinoline was employed, only oligomeric products were obtained. On the contrary, 5,7‐dinitro‐8‐hydroxyquinoline gave linear polyethylene (PE), but with a modest activity. For the catalyst based on 5‐nitro‐8‐hydroxyquinoline, the productivity was largely dependent on the content of free trimethylaluminum (TMA) present in the commercial aluminoxane. The progressive optimization of the TMA/oligomeric methylaluminoxane ratio increased the productivity, which reached 700 kg of PE/(mol of Ni × h), by an order of magnitude. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 200–206, 2006 相似文献
84.
Juray De Wilde Denis Constales Geraldine J. Heynderickx Guy B. Marin 《International Journal of Multiphase Flow》2007
The propagation speeds of linear waves in gas–solid suspensions depend strongly on the solids volume fraction and the wave frequency. The latter is due to gas–solid momentum transfer and allows a simple test on filtered gas–solid momentum transfer models. Such models may predict linear wave propagation speeds different from those obtained with the non-filtered model at wave frequencies higher than the filter frequency, but not at wave frequencies lower than the filter frequency. 相似文献
85.
Julio Penin Santos Fernando J.G. Landgraf Geraldo Caixeta Guimarães 《Journal of magnetism and magnetic materials》2006
The paper describes effect of texture on the anisotropy of magnetic properties and shows that an Epstein strip arrangement including strips cut in a direction 45° to the rolling direction gives property values that are closer to the average values than the traditional RD+TD arrangement. 相似文献
86.
Marcos F. de Campos Marília Emura Fernando J.G. Landgraf 《Journal of magnetism and magnetic materials》2006
Electrical steels, when submitted to operation, present continuous decrease of their magnetic properties, depending on the carbon content. This effect is attributed to the increase of the size of carbides, a process also known as coarsening or Ostwald Ripening. Loss separation can offer a better understanding of this phenomenon. Experimental results show that all effect of aging is inside the hysteresis loss component, with the excess losses unaffected. The carbon content in electrical steels should be less than 25 ppm to avoid magnetic aging. 相似文献
87.
S. De Nicola A. E. Kaplan S. Martellucci P. Mormile G. Pierattini J. Quartieri 《Applied physics. B, Lasers and optics》1989,49(5):441-444
We have observed a hysteretic (bistable) reflection of a Gaussian laser beam at the interface between glass and a liquid solution of polystyrene microspheres as nonlinear medium with both branches of the hysteretic curve being stable, in contrast to the results of previous experiments. 相似文献
88.
89.
Anna De Simone 《Proceedings of the American Mathematical Society》1998,126(10):2919-2926
We provide some conditions which are equivalent to the uniqueness of Hewitt-Yosida-type decomposition and Lebesgue-type decomposition for real valued additive functions defined on orthomodular posets.
90.
Fernando Torres 《Semigroup Forum》1997,55(3):364-379
This work was realized while the author was ICTP (Trieste - Italy) with a grant from the International Atomic Energy Agency
and UNESCO. 相似文献