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排序方式: 共有476条查询结果,搜索用时 15 毫秒
111.
This paper deals with the asymptotic behavior of strong solutions to the 3D Navier–Stokes equations with a nonlinear damping term |u|β−1u(β≥3). First, we establish an upper bound for the difference between the solution of our equation and the heat equation in L2 space. Then, we optimize the upper bound of decay for the solutions and obtain their algebraic lower bound by using Fourier Splitting method. 相似文献
112.
Won Keun Min 《Applied Mathematics Letters》2012,25(3):310-314
We introduce and study the concept of similarity between soft sets, which is an extension of the equality for soft set theory. We also introduce the concepts of conjunction parameter (α∧β) and disjunction parameter (α∨β) of ordered pair parameter 〈α,β〉 for soft set theory, and we investigate modified operations of soft set theory in terms of ordered parameters. 相似文献
113.
Marianna A. Shubov 《Mathematische Nachrichten》2020,293(3):585-610
Three control problems for the system of two coupled differential equations governing the dynamics of an energy harvesting model are studied. The system consists of the equation of an Euler–Bernoulli beam model and the equation representing the Kirchhoff's electric circuit law. Both equations contain coupling terms representing the inverse and direct piezoelectric effects. The system is reformulated as a single evolution equation in the state space of 3-component functions. The control is introduced as a separable forcing term on the right-hand side of the operator equation. The first control problem deals with an explicit construction of that steers an initial state to zero on a time interval [0, T]. The second control problem deals with the construction of such that the voltage output is equal to some given function (with being given as well). The third control problem deals with an explicit construction of both the force profile, , and the control, , which generate the desired voltage output . Interpolation theory in the Hardy space of analytic functions is used in the solution of the second and third problems. 相似文献
114.
X. Wang L. J. Sudak C. Q. Ru 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2007,58(3):488-509
A general method is presented for the rigorous solution of Eshelby’s problem concerned with an arbitrary shaped inclusion
embedded within one of two dissimilar elastic half-planes in plane elasticity. The bonding between the half-planes is considered
to be imperfect with the assumption that the interface imperfections are uniform.
Using analytic continuation, the basic boundary value problem is reduced to a set of two coupled nonhomogeneous first-order
differential equations for two analytic functions defined in the lower half-plane which is free of the thermal inclusion.
Using diagonalization, the two coupled differential equations are decoupled into two independent nonhomogeneous first-order
differential equations for two newly defined analytic functions. The resulting closed-form solutions are given in terms of
the constant imperfect interface parameters and the auxiliary function constructed from the conformal mapping which maps the
exterior of the inclusion onto the exterior of the unit circle.
The method is illustrated using several examples of an imperfect interface. In particular, when the same degree of imperfection
is realized in both the normal and tangential directions between the two half-planes, a thermal inclusion of arbitrary shape
in the upper half-plane does not cause any mean stress to develop in the lower half-plane. Alternatively, when the imperfect
interface parameters are not equal, then a nonzero mean stress will be induced in the lower half-plane by the thermal inclusion
of arbitrary shape in the upper half-plane. Detailed results are presented for the mean stress and the interfacial normal
and shear stresses caused by a circular and elliptical thermal inclusion, respectively. Results from these calculations reveal
that the imperfect bonding condition has a significant effect on the internal stress field induced within the inclusion as
well as on the interfacial normal and shear stresses existing between the two half-planes especially when the inclusion is
near the imperfect interface. 相似文献
115.
A. Morita 《Applied Physics A: Materials Science & Processing》1986,39(4):227-242
Black phosphorus is a narrow-gap semiconductor newly attracting attention because of recent success in growing single crystals at a high temperature under a high pressure. This review covers recent research work on the preparation, the crystal structure, the band structure, the electrical and optical properties, and the superconductivity of black phosphorus. 相似文献
116.
P. Malits 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2007,58(3):475-487
A novel type of trigonometric dual series equations is suggested for studying electric and shear displacement fields induced
by a periodic system of tape-shaped electrode films which are situated on the surface of a piezoelectric layer symmetrically
with respect to its midplane.
The algorithm is based on discontinuous series containing novel special functions. The problem is reduced to a Fredholm integral
equation of the second kind with a strictly positive operator. This equation is convenient for analytical and numerical treatment.
Leading terms of asymptotic expansions for physical characteristics are found for a wide range of the parameters. 相似文献
117.
A certain regularization technique for contact problems leads to a family of problems that can be solved efficiently using infinite-dimensional semismooth Newton methods, or in this case equivalently, primal–dual active set strategies. We present two procedures that use a sequence of regularized problems to obtain the solution of the original contact problem: first-order augmented Lagrangian, and path-following methods. The first strategy is based on a multiplier-update, while path-following with respect to the regularization parameter uses theoretical results about the path-value function to increase the regularization parameter appropriately. Comprehensive numerical tests investigate the performance of the proposed strategies for both a 2D as well as a 3D contact problem. 相似文献
118.
The pure azimuthal shear problem for a circular cylindrical tube of nonlinearly elastic material, both isotropic and anisotropic,
is examined on the basis of a complementary energy principle. For particular choices of strain-energy function, one convex
and one non-convex, closed-form solutions are obtained for this mixed boundary-value problem, for which the governing differential
equation can be converted into an algebraic equation. The results for the non-convex strain energy function provide an illustration
of a situation in which smooth analytic solutions of a nonlinear boundary-value problem are not global minimizers of the energy
in the variational statement of the problem. Both the global minimizer and the local extrema are identified and the results
are illustrated for particular values of the material parameters.
相似文献
119.
We revisit a venerable question: what is the nature of the ordering in a superconductor? We find that the answer is properly that the superconducting state exhibits topological order in the sense of Wen, i.e., that while it lacks a local order parameter, it is sensitive to the global topology of the underlying manifold and exhibits an associated fractionalization of quantum numbers. We show that this perspective unifies a number of previous observations on superconductors and their low lying excitations and that this complex can be elegantly summarized in a purely topological action of the “BF” type and its elementary quantization. On manifolds with boundaries, the BF action correctly predicts non-chiral edge states, gapped in general, but crucial for fractionalization and establishing the ground state degeneracy. In all of this the role of the physical electromagnetic fields is central. We also observe that the BF action describes the topological order in several other physically distinct systems thus providing an example of topological universality. 相似文献
120.
Variational iteration method is introduced to solve two-point boundary value problems. Numerical results demonstrate that the method is promising and may overcome the difficulty arising in Adomian decomposition method. 相似文献