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991.
992.
Yu. M. Ryzhov 《Ukrainian Mathematical Journal》1989,41(5):542-546
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 41, No. 5, pp. 626–631, May, 1989. 相似文献
993.
994.
Consider the problem of rolling a dynamically asymmetric balanced ball (the Chaplygin ball) over a sphere. Suppose that the
contact point has zero velocity and the projection of the angular velocity to the normal vector of the sphere equals zero.
This model of rolling differs from the classical one. It can be realized, in some approximation, if the ball is rubber coated
and the sphere is absolutely rough. Recently, J. Koiller and K. Ehlers pointed out the measure and the Hamiltonian structure
for this problem. Using this structure we construct an isomorphism between this problem and the problem of the motion of a
point on a sphere in some potential field. The integrable cases are found.
相似文献
995.
A. L. Ivanovskii 《Theoretical and Experimental Chemistry》2007,43(1):1-27
The present state of research on the production and modeling of nanostructures based on titanium carbide-a typical representative
of an extensive class of carbides of d-and f-metals-is reviewed. Methods for the synthesis of various Ti-C nanostructures
(molecular clusters, nanocrystallites, nanospheres, nanofibers, nanowires) are examined, and their morphology, atomic structure,
and known physicochemical characteristics are described. Theoretical models of the atomic structure and properties of new
types of nanostructures in the titanium-carbon system (endo-and exohedral titanofullerenes, “hybrid” structures based on carbon
nanotubes, the so-called peapods, nanocables, and a number of others) and the prospects for their application as components
of nanoceramics, hydrogen accumulators, materials for spintronics, etc. are discussed.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 1, pp. 1–23, January–February, 2007. 相似文献
996.
O. Yu. Dashkova 《Algebra and Logic》2007,46(5):297-302
We are concerned with infinite-dimensional locally soluble linear groups of infinite central dimension that are not soluble
A3-groups and all of whose proper subgroups, which are not soluble A3-groups, have finite central dimension. The structure of groups in this class is described. The case of infinite-dimensional
locally nilpotent linear groups satisfying the specified conditions is treated separately. A similar problem is solved for
infinite-dimensional locally soluble linear groups of infinite fundamental dimension that are not soluble A3-groups and all of whose proper subgroups, which are not soluble A3-groups, have finite fundamental dimension.
__________
Translated from Algebra i Logika, Vol. 46, No. 5, pp. 548–559, September–October, 2007. 相似文献
997.
We investigate the existence and stability of solutions for higher-order two-point boundary value problems in case the differential
operator is not necessarily positive definite, i.e. with superlinear nonlinearities. We write an abstract realization of the
Dirichlet problem and provide abstract existence and stability results which are further applied to concrete problems. 相似文献
998.
We consider a shock-type wave solution of the modified quintic complex Ginzburg-Landau equation and make a numerical study
of its spatiotemporal stability. Discussions related to the behavior of this front wave are introduced and it is shown how
the velocities of the wave can be used to collect information concerning the pattern formation in the system.
Published in Neliniini Kolyvannya, Vol. 10, No. 2, pp. 270–276, April–June, 2007. 相似文献
999.
Let A be an algebra without unit. If ∥ ∥ is a complete regular norm on A it is known that among the regular extensions of ∥ ∥ to the unitization of A there exists a minimal (operator extension) and maximal (ℓ1-extension) which are known to be equivalent. We shall show that the best upper bound for the ratio of these two extensions
is exactly 3. This improves the results represented by A. K. Gaur and Z. V. Kovářík and later by T. W. Palmer.
The second author was partially supported by the grant No. 201/03/0041 of GAČR. 相似文献
1000.
A nonlocal difference scheme for the heat conduction equation with a real parameter γ > 1 or γ < 0 in the boundary condition is considered. Thus, the analysis of this problem is generalized to all real values of the parameter in the boundary condition. The spectrum of the spatial operator of the scheme is studied. The results obtained are used to formulate a stability criterion for the difference scheme. The case γ = ?1 proves to be special, because the system of eigenfunctions of the operator does not form a basis in the space of grid functions. 相似文献