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71.
The gas entrainment in a hollow cone spray submitted to variable density is studied experimentally in order to better understand
the effect on mixture formation. Particle image velocimetry on fluorescent tracers, associated with a specific processing
of the instantaneous velocity fields have been applied to obtain measurement in the close vicinity of the spray edge. In the
“quasi-steady” region of the spray, important effect of the ambient density on the mass flow rate of entrained gas
have been pointed out. The axial evolution of is in good agreement with an integral model that takes the momentum exchange between phases into account. 相似文献
72.
We study the six-field model of fluids (ET6) derived from extended thermodynamics. The six fields are the mass density, the velocity, the temperature, and the dynamic pressure (nonequilibrium pressure). We present the basic system of field equations of ET6. And we elucidate its characteristic features through the studies of the singular limit from polyatomic to monatomic rarefied gases, of hydrodynamic fluctuation, and of a hard-sphere system. Open problems remained in ET6 at present are also pointed out. 相似文献
73.
R. Bernabei P. Belli F. Montecchia W. Di Nicolantonio G. Ignesti A. Incicchitti D. Prosperi C. J. Dai L. K. Ding H. H. Kuang J. M. Ma 《Physics letters. [Part B]》1999,450(4):40
The results achieved with a statistics of 14962 kg·day, collected with the large mass highly radiopure DAMA NaI(Tl) set-up, are described and investigated in terms of WIMP annual modulation signature. A maximum likelihood analysis of these data, combined with the statistics of 4549 kg·day previously published (total statistics of 19511 kg·day), favours the hypothesis of presence of an annual modulation at 99.6% C.L. 相似文献
74.
Summary In this note we investigate the possibility to identify a “dark matter” signal by means of low-background anisotropic scintillators. 相似文献
75.
76.
Baldicchi M Nesterenko AV Prosperi GM Shirkov DV Simolo C 《Physical review letters》2007,99(24):242001
We exploit theoretical results on the meson spectrum within the framework of a Bethe-Salpeter (BS) formalism adjusted for QCD, in order to extract an experimental coupling alpha(s)exp (Q2) below 1 GeV by comparison with the data. Our results for alpha(s)exp (Q2) exhibit a good agreement with the infrared safe analytic perturbation theory (APT) coupling from 1 GeV down to 200 MeV. As a main result, we claim that the combined BS-APT theoretical scheme provides us with a rather satisfactory correlated understanding of very high- and low-energy phenomena. 相似文献
77.
We consider a system of N balance laws compatible with an entropy principle and convex entropy density. Using the special symmetric form induced by
the main field, we define the concept of principal subsystem associated with the system. We prove that the 2
N
−2 principal subsystems are also symmetric hyperbolic and satisfy a subentropy law. Moreover we can verify that for each principal subsystem the maximum (minimum) characteristic velocity is not larger (smaller)
than the maximum (minimum) characteristic velocity of the full system. These are the subcharacteristic conditions. We present
some simple examples in the case of the Euler fluid. Then in the case of dissipative hyperbolic systems we consider an equilibrium
principal subsystem and we discuss the consequences in the setting of extended thermodynamics. Finally in the moments approach
to the Boltzmann equation we prove, as a consequence of the previous result, that the maximum characteristic velocity evaluated
at the equilibrium state does not decrease when the number of moments increases.
(Accepted October 6, 1995) 相似文献
78.
79.
We prove that in a family of projective threefolds defined over an algebraically closed field, the locus of rational fibers is a countable union of closed subsets of the locus of separably rationally connected fibers. When the ground field has characteristic zero, this implies that the locus of rational fibers in a smooth family of projective threefolds is the union of at most countably many closed subfamilies. 相似文献
80.