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911.
The HERA - B Collaboration I. Abt et al. 《The European Physical Journal C - Particles and Fields》2003,26(3):345-355
Using the HERA - B detector, the production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The production was tagged via inclusive bottom quark decays into by exploiting the longitudinal separation of decay vertices from the primary proton-nucleus interaction. Both e
+
e
-
and channels have been reconstructed and the combined analysis yields the cross section .
Received: 6 June 2002 / Revised version: 2 September 2002 / Published online: 8 November 2002 相似文献
912.
J. S. Yang Z. G. Chen Y. T. Hu S. N. Jiang S. H. Guo 《Archive of Applied Mechanics (Ingenieur Archiv)》2007,77(10):689-696
We study thickness-twist vibrations and waves in an unbounded, multi-sectioned piezoelectric plate of crystals with 6 mm symmetry
or polarized ceramics. An exact solution from the three-dimensional equations of piezoelectricity is obtained. Basic vibration
and wave propagation characteristics are calculated based on the solution. The results are useful in the understanding and
design of plate resonators, filters and acoustic wave sensors of ZnO, AlN and polarized ceramics. 相似文献
913.
Yu. I. Samoilenko 《Ukrainian Mathematical Journal》2007,59(11):1750-1767
We propose and investigate a mathematical model of an open bilinear control system for the conversion of heat energy in a
coherent form. We show that the use of a combinational parametric resonance formed by the control system in a one-temperature
ensemble of weakly dissipative elastic-gyroscopic subsystems enables one to obtain a positive energy output without using
any cooling device apart from the control system.
__________
Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 59, No. 11, pp. 1557–1573, November, 2007. 相似文献
914.
If M is an isoparametric hypersurface in a sphere S
n
with four distinct principal curvatures, then the principal curvatures κ1, . . . , κ4 can be ordered so that their multiplicities satisfy m
1 = m
2 and m
3 = m
4, and the cross-ratio r of the principal curvatures (the Lie curvature) equals −1. In this paper, we prove that if M is an irreducible connected proper Dupin hypersurface in R
n
(or S
n
) with four distinct principal curvatures with multiplicities m
1 = m
2 ≥ 1 and m
3 = m
4 = 1, and constant Lie curvature r = −1, then M is equivalent by Lie sphere transformation to an isoparametric hypersurface in a sphere. This result remains true if the
assumption of irreducibility is replaced by compactness and r is merely assumed to be constant.
相似文献
915.
In a seminal paper, Martin Clark (Communications Systems and Random Process Theory, Darlington, 1977, pp. 721–734, 1978) showed how the filtered dynamics giving the optimal estimate of a Markov chain observed in Gaussian noise can be expressed
using an ordinary differential equation. These results offer substantial benefits in filtering and in control, often simplifying
the analysis and an in some settings providing numerical benefits, see, for example Malcolm et al. (J. Appl. Math. Stoch.
Anal., 2007, to appear).
Clark’s method uses a gauge transformation and, in effect, solves the Wonham-Zakai equation using variation of constants.
In this article, we consider the optimal control of a partially observed Markov chain. This problem is discussed in Elliott
et al. (Hidden Markov Models Estimation and Control, Applications of Mathematics Series, vol. 29, 1995). The innovation in our results is that the robust dynamics of Clark are used to compute forward in time dynamics for a simplified
adjoint process. A stochastic minimum principle is established. 相似文献
916.
Considering a plane hyperbolic system with time-periodic coefficients, we construct a version of the direct Lyapunov method with the condition on the derivative of the Lyapunov functional along the trajectories of the system which is weakened by use of periodicity of the coefficients. We exhibit an illustrative example. 相似文献
917.
918.
A. S. Kalitvin 《Journal of Mathematical Sciences》2007,145(5):5247-5251
919.
E. Hernández L. Rodríguez-Marín 《Journal of Optimization Theory and Applications》2007,134(1):119-134
In this paper, we study optimization problems where the objective function and the binding constraints are set-valued maps
and the solutions are defined by means of set-relations among all the images sets (Kuroiwa, D. in Takahashi, W., Tanaka, T.
(eds.) Nonlinear analysis and convex analysis, pp. 221–228, 1999). We introduce a new dual problem, establish some duality theorems and obtain a Lagrangian multiplier rule of nonlinear type
under convexity assumptions. A necessary condition and a sufficient condition for the existence of saddle points are given.
The authors thank the two referees for valuable comments and suggestions on early versions of the paper. The research of the
first author was partially supported by Ministerio de Educación y Ciencia (Spain) Project MTM2006-02629 and by Junta de Castilla
y León (Spain) Project VA027B06. 相似文献
920.
F. Calogero 《Theoretical and Mathematical Physics》2007,152(1):882-893
We review recent results about classical isochronous systems characterized by the presence of an open (hence fully dimensional)
region in their phase space in which all their solutions are completely periodic (i.e., periodic in all degrees of freedom)
with the same fixed period (independent of the initial data provided they are inside the isochronicity region). We report
a technique for generating such systems, whose wide applicability justifies the statement that isochronous systems are not
rare. We also present an analogous technique applicable to a vast class of Hamiltonian systems and generating isochronous
Hamiltonian systems. We also report some results concerning the quantized versions of such systems. 相似文献