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The threshold behaviour of pion production presented in our earlier work is successfully compared with the new SPEAR data. By using duality and sum rules we derive FT(π+)(x) ≈ FL(π+)(x) ≈ FT(π0)(x) ? FL(π0)(x) for x near 1. An accompanying results is for large s. 相似文献
54.
Roberto Greco Carl R. Taylor Ole Kramer John D. Ferry 《Journal of Polymer Science.Polymer Physics》1975,13(9):1687-1694
Further stress relaxation experiments, mostly at 50°C, are reported on mixtures of crosslinkable ethylene–propylene terpolymer with saturated ethylene–propylene copolymer (molecular weights 3.6 and 45 × 104) containing up to 50% by weight of copolymer, crosslinked by sulfur to leave the saturated copolymer unattached and free to reptate in the copolymer network. Stress relaxation was measured in small simple elongations (stretch ratio about 1.15) on samples which had been extracted to remove a large part of the unattached copolymer and dried. The relative increase in modulus at long times (104 sec) increased with the proportion extracted; at short times (1 sec), extraction of the lower molecular weight copolymer increased the modulus to about the same extent but extraction of the higher molecular weight copolymer affected it very little. The relaxation modulus of the copolymer extracted from sample 50H (50% copolymer of high molecular weight), obtained by difference, agreed with that for the total copolymer except for a small difference probably attributable to molecular weight selectivity in the extraction. Stress relaxation was measured on sample 50H at six higher elongations up to a stretch ratio of 3. The dependence of stress on time and strain was consistent with an analysis based on the following assumptions: (a) linear additivity of the network and unattached copolymer contributions, (b) strain–time factorization of the stress contributions from the individual components, (c) a strain dependence for the unattached component corresponding to the presence of a Mooney–Rivlin C2 term only, (d) a strain dependence for the network component which does not follow the Mooney–Rivlin equation but is dominated by a simple neo-Hookean term. 相似文献
55.
We show that a new class of large infrared corrections in QCD can be easily observable by measuring the moments of the jets energy deposited in a calorimeter in single cone experiments. 相似文献
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Gabriele H. Greco 《Annali dell'Universita di Ferrara》1980,26(1):213-218
Riassunto In questo articolo si dimostra che una misura finitamente additiva e limitata, definita su un'algebra di Boole, è continua
se e solo se verifica la proprietà di Darboux. Inoltre si danno (th. 2 e 3) due caratterizzazioni delle algebre di Boole che
sono superatomiche, usando le misure continue.
Résumé Dans cet article on démontre qun'une mesure réelle simplement additive et bornée, définie sur une algèbre de Boole, est continue si et seulement si elle vérifie la propriété de Darboux (voir th. 1). On démontre en outre qu'une algèbre de Boole est superatomique si et seulement si toute mesure s.a.b. continue admet une décomposition de Hahn (voir th. 2), on si et seulement si il y a une mesure s.a.b.-continue μ telle que toute autre mesure s.a.b. continue soit absolument continue par rapport à μ (voir th. 3).相似文献
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Tuned mass sampers (TMDs) are widely used strategies for vibration control in many engineering applications, so that many TMD optimization criteria have been proposed till now. However, they normally consider only TMD stiffness and damping as design variables and assume that the tuned mass is a pre-selected value. In this work a more complete approach is proposed and then also TMD mass ratio is optimized. A standard single degree of freedom system is investigated to evaluate TMD protection efficiency in case of excitation at the support. More precisely, this model is used to develop two different optimizations criteria which minimize the main system displacement or the inertial acceleration. Different environmental conditions described by various characterizations of the input, here modelled by a stationary filtered stochastic process, are considered. Results show that all solutions obtained considering also the mass of the TMD as design variable are more efficient if compared with those obtained without it. However, in many cases these solutions are inappropriate because the optimal TMD mass is greater than real admissible values in practical technical applications for civil and mechanical engineering. Anyway, one can deduce that there are some interesting indications for applications in some actual contexts. In fact, the results show that there are some ranges of environmental parameters ranges where results attained by the displacement criterion are compatible with real applications requiring some percent of main system mass. Finally, the present research gives promising indications for complete TMD optimization application in emerging technical contexts, as micromechanical devices and nano resonant beams. 相似文献
60.
Ablikim M Achasov MN An L An Q An ZH Bai JZ Baldini R Ban Y Becker J Berger N Bertani M Bian JM Boyko I Briere RA Bytev V Cai X Cao GF Cao XX Chang JF Chelkov G Chen G Chen HS Chen JC Chen ML Chen SJ Chen Y Chen YB Cheng HP Chu YP Cronin-Hennessy D Dai HL Dai JP Dedovich D Deng ZY Denysenko I Destefanis M Ding Y Dong LY Dong MY Du SX Duan MY Fan RR Fang J Fang SS Feldbauer F Feng CQ Fu CD Fu JL Gao Y Geng C Goetzen K Gong WX Greco M Grishin S Gu MH Gu YT Guan YH Guo AQ Guo LB Guo YP Hao XQ 《Physical review letters》2010,105(26):261801
The decays ψ'→γπ(0), γη and γη' are studied using data collected with the BESIII detector at the BEPCII e(+)e(-) collider. The processes ψ'→γπ(0) and ψ'→γη are observed for the first time with signal significances of 4.6σ and 4.3σ, respectively. The branching fractions are determined to be B(ψ'→γπ(0))=(1.58±0.40±0.13)×10(-6), B(ψ'→γη)=(1.38±0.48±0.09)×10(-6), and B(ψ'→γη')=(126±3±8)×10(-6), where the first errors are statistical and the second ones systematic. 相似文献