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971.
In this paper, we apply a three-stage-DEA model to the Spanish Professional Football League, which means separating the teams’
economic behaviour into three components: operating efficiency—of the offence and defence—athletic or operating effectiveness,
and social effectiveness. The results showed that the technical inefficiency of the defence is greater than that of the offence,
both being caused by aspects linked to the poor management of players’ abilities and by the football team’s size. Teams showed
a favourable evolution of their offensive and defensive efficiency during the 2004/2005 season and to a lesser extent in the
season before. The point system assigned by the professional football league regulations evaluates the teams’ athletic effectiveness,
but we detected that the teams with the most experience perform athletically in a more effective manner. Their social effectiveness
is strongly related to the level of play in itself and to factors linked to their PFL ranking: participation in international
competitions for important football teams; or the struggle of minor football teams to stay in the first division. 相似文献
972.
J. Xu J. Mei X.H. Huang X. Li Z. Li W. Li K. Chen 《Applied Physics A: Materials Science & Processing》2005,80(1):123-126
The effect of nitrogen surface doping on the electron field emission characteristics of hydrogenated amorphous carbon films was studied. It was found that the emission threshold electric field decreased after nitrogen surface doping which indicated the reduction of the emission barrier at the film surface. It was demonstrated that this improvement arose from the decrease of the effective work function due to the formation of a dipole layer induced by chemical termination and chemical structural change on the film surface. PACS 52.75.Xx; 73.30 +y; 73.61.Jc 相似文献
973.
Q. Gong R. N tzel P.J. van Veldhoven T.J. Eijkemans J.H. Wolter 《Journal of Crystal Growth》2005,280(3-4):413-418
We report on the shape transition from InAs quantum dashes to quantum dots (QDs) on lattice-matched GaInAsP on InP(3 1 1)A substrates. InAs quantum dashes develop during chemical-beam epitaxy of 3.2 monolayers InAs, which transform into round InAs QDs by introducing a growth interruption without arsenic flux after InAs deposition. The shape transition is solely attributed to surface properties, i.e., increase of the surface energy and symmetry under arsenic deficient conditions. The round QD shape is maintained during subsequent GaInAsP overgrowth because the reversed shape transition from dot to dash is kinetically hindered by the decreased ad-atom diffusion under arsenic flux. 相似文献
974.
975.
976.
977.
The treatment of tertiary esters with triphenylphosphine and iodine under mild conditions gives the most stable alkene in good yield. Formates, acetates and trifluoroacetates were studied. 相似文献
978.
Theresa J. Hermel-Davidock H. Sean Tang Daniel J. Murray Stephen F. Hahn 《Journal of polymer science. Part A, Polymer chemistry》2007,45(24):3338-3348
It has been found that by the addition of low concentrations of an amphiphilic block copolymer to an epoxy resin, novel disordered morphologies can be formed and preserved through curing. This article will focus on characterizing the influence of the block copolymer and casting solvent on the templated morphology achieved in the thermoset sample. The ultimate goal of this work is to determine the parameters that would control the microphase morphology produced. Epoxy resins blended with a series of amphiphilic block copolymers based on hydrogenated polyisoprene (polyethylene-alt-propylene or PEP) and polyethylene oxide (PEO), specifically, were investigated. In this article, the cure-induced order–order phase transition from the spherical to wormlike micelle morphology will also be discussed. It is proposed that the formation of the wormlike micelle structure from the spherical micelle structure is similar to the phase transition behavior that occurs in dilute block copolymer solutions as a function of the influence of the solvent on micelle morphology. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3338–3348, 2007 相似文献
979.
We introduce a random perturbed version of the classical fidelity and we show that it converges with the same rate of decay
of correlations, but not uniformly in the noise. This makes the classical fidelity unstable in the zero-noise limit. 相似文献
980.
Formulas that include the contribution from dipole-distributed anomalous masses represented as layers distributed in height relative to the reference ellipsoid to the gravitational field in the quadratic approximation have been derived. The relationships between the expansion coefficients of some function and its square in terms of spherical functions have been established. The contribution from the relief masses and the density jump at the Mohorovicic discontinuity is used to illustrate the results. 相似文献