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991.
A. D. Zorina L. V. Balykina O. V. Nazarova A. A. Rebezov 《Russian Journal of Applied Chemistry》2006,79(4):654-659
Polymeric derivatives of dammarane triterpenoids with both labile and strong (covalent) polymer-triterpenoid bonds were prepared from N-vinylpyrrolidone copolymers. 相似文献
992.
We study a 7-dimensional brane world scenario with a Ricci-flat 3-brane residing in the core of a composite monopole defect, i.e., a defect composed of a 't Hooft–Polyakov and a global monopole. Admitting a direct interaction between the two bosonic sectors of the theory, we analyse the structure of the space–time in the limits of small, respectively large direct interaction coupling constant. For large direct interaction, the global monopole disappears from the system and leaves behind a negative cosmological constant in the bulk such that gravity-localising solutions are possible without a priori introduction of a bulk cosmological constant. 相似文献
993.
994.
995.
996.
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
997.
D. V. Bolotov 《Mathematical Notes》2007,82(1-2):10-12
We prove that the hyperbolic space L n cannot be immersed in an Euclidean space E n+m with a flat normal connection provided the module of the mean curvature vector is bounded. 相似文献
998.
We study problems of interpolation of positive linear operators in couples of ordered Banach spaces. From this viewpoint, we study couples of noncommutative spaces L 1, L ∞ associated with weights and traces on von Neumann algebras. 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.
S. V. Tyshkevich 《Mathematical Notes》2007,81(5-6):851-853