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21.
Form invariance and conserved quantities of Nielsen equations of relativistic variable mass nonholonomic systems 总被引:1,自引:0,他引:1
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In this paper, the definition and criterion of the form invariance of Nielsen equations for relativistic variable mass nonholonomic systems are given. The relation between the form invariance and the Noether symmetry is studied.Finally, we give an example to illustrate the application of the result. 相似文献
22.
Filtering for linear systems with noise correlation and its application to singular systems
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In this paper, an optimal filter for a stochastic linear system with previous stage noise correlation is designed.Based on this result, together with the decomposition techniques of the stochastic singular linear system, the design ofan optimal filter for a stochastic singular linear system is given. 相似文献
23.
A study on the correlation between electrical percolation and viscoelastic percolation for carbon black (CB) and carbon fiber (CF) filled high‐density polyethylene (HDPE) conductive composites was carried out through an examination of the filler concentration (?) dependence of the volume resistivity (ρ) and dynamic viscoelastic functions. For CB/HDPE composites, when ? was higher than the modulus percolation threshold (?G ~ 15 vol %), the dynamic storage modulus (G′) reached a plateau at low frequencies. The relationship between ρ and the normalized dynamic storage modulus (Gc′/Gp′, where Gc′ and Gp′ are the dynamic storage moduli of the composites and the polymer matrix, respectively) was studied. When ? approached a critical value (?r), a characteristic change in Gc′/Gp′ appeared. The critical value (Gc′/G′p)c was 9.80, and the corresponding ?r value was 10 vol %. There also existed a ? dependence of the dynamic loss tangent (tan δ) and a peak in a plot of tan δ versus the frequency when ? approached a loss‐angle percolation (?δ = 9 vol %). With parameter K substituted for A, a modified Kerner–Nielson equation was obtained and used to analyze the formation of the network structure. The viscoelastic percolation for CB/HDPE composites could be verified on the basis of the modified equation, whereas no similar percolation was found for CF/HDPE composites. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1199–1205, 2004 相似文献
24.
We present some results whose central theme is the phenomenon of the first eigenvalue of the Laplacian and conductance of
the dynamical system. Our main tool is a method for studying how the hyperbolic metric on a Riemann surface behaves under
deformation of the surface. With this model, we show that there are variation of the first eigenvalue of the laplacian and
the conductance of the dynamical system, with the Fenchel–Nielsen coordinates, that characterize the surface. 相似文献
25.
26.
In this work we show that the Wecken theorem for periodic points holds for periodic homeomorphisms on closed surfaces, which therefore completes the periodic point theory in such a special case. Using it we derive the set of homotopy minimal periods for such homeomorphisms. Moreover we show that the results hold for homotopically periodic self-maps of closed surfaces. This let us to re-formulate our results as a statement on properties of elements of finite order in the group of outer automorphisms of the fundamental group of a surface with non-positive Euler characteristic. 相似文献
27.
We give a brief survey of some developments in Nielsen fixed point theory. After a look at early history and a digress to various generalizations, we confine ourselves to several topics on fixed points of self-maps on manifolds and polyhedra. Special attention is paid to connections with geometric group theory and dynamics, as well as some formal approaches. 相似文献
28.
Let R = ?[C] be the integral group ring of a finite cyclic group C. Dennis et al. [4] proved that R is a generalized Euclidean ring in the sense of Cohn [3], i.e., SLn(R) is generated by the elementary matrices for all n. We prove that every proper quotient of R is also a generalized Euclidean ring. 相似文献
29.
In this paper we study, the Reidemeister zeta function. We prove rationality and functional equations of the Reidemeister zeta function of an endomorphism of finite group. We also obtain these results for eventually commutative endomorphisms. These results are applied to the theory of Reidemeister and Nielsen numbers of self-maps of topological spaces. Our method is to identify the Reidemeister number of a group endomorphism with the number of fixed points in the unitary dual. As a consequence, we show that the Reidemeister torsion of the mapping torus of the unitary dual is a special value of the Reidemeister zeta function. We also prove certain congruences for Reidemeister numbers which are equivalent to a Euler product formula for the Reidemeister zeta function. The congruences are the same as those found by Dold for Lefschetz numbers. 相似文献
30.
R. Craggs 《Topology and its Applications》1988,30(3):237-252
The possibility is considered that the Andrews-Curtis conjecture, if false, may provide obstructions to the cancellation of 1- and 3-handles in a simply connected 4-manifold. An algebra is developed for the simultaneous algebraic reading of attaching maps for 2-handles and their duals, and it is shown that obstructions to 1- and 3-handle cancellation cannot bedetected in this algebra. 相似文献