共查询到20条相似文献,搜索用时 15 毫秒
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Qiaohua Yang 《Journal of Mathematical Analysis and Applications》2008,341(2):998-1006
Let G be a simple Lie group of real rank one and N be in the Iwasawa decomposition of G. We prove a refined version of the Sobolev inequality on N in presence of symmetry. 相似文献
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Qiao Hua Yang 《数学学报(英文版)》2010,26(8):1575-1590
Let G be a simple Lie group of real rank one and N be in the Iwasawa decomposition of G. Under the assumption of some symmetries, we obtain an existent result for the nonlinear equation △NU + (1 + ∈K(x, z))u2*-1 = 0 on N, which generalizes the result of Malchiodi and Uguzzoni to the Kohn's subelliptic context on N in presence of symmetry. 相似文献
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《Journal of Functional Analysis》1987,74(1):160-197
Consider an abstract Hamiltonian system which is invariant under a one-parameter unitary group of operators. By a “solitary wave” we mean a solution the time development of which is given exactly by the one-parameter group. We find sharp conditions for the stability and instability of solitary waves. Applications are given to bound states and traveling waves of nonlinear PDEs such Klein-Gordon and Schrödinger equations. 相似文献
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The effect of uniaxial tension on the density of polycaproamide has been studied in the temperature region from +20 to +150°C. The density measurements were made by the flotation method. It is shown that the relative change of density increases with temperature. An empirical formula for the density distribution along the stretched specimen is proposed.Severodonetsk Glass-Reinforced Plastics Plant. Lugansk Mechanical Engineering Institute. Translated from Mekhanika Polimerov, Vol. 4, No. 4, pp. 760–761, July–August, 1968. 相似文献
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《Journal of computational science》2014,5(5):696-700
Uniformly distributed point sets on the unit sphere with and without symmetry constraints have been found useful in many scientific and engineering applications. Here, a novel variant of the Thomson problem is proposed and formulated as an unconstrained optimization problem. While the goal of the Thomson problem is to find the minimum energy configuration of N electrons constrained on the surface of the unit sphere, this novel variant imposes a new symmetry constraint – mirror reflection symmetry with the x–y plane as the plane of symmetry. Qualitative features of the two-dimensional projection of the optimal configurations are briefly mentioned and compared to the ground-state configurations of the two dimensional system of charged particles laterally confined by a parabolic potential well. 相似文献
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We prove some existence results for the Webster scalar curvature problem on the Heisenberg group and on the unit sphere of n+1, under the assumption of some natural symmetries of the prescribed curvatures. We use variational and perturbation techniques. Mathematics Subject Classification (2000) 35J20, 35H20, 35J60, 43A80 相似文献
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《Journal of Applied Mathematics and Mechanics》2014,78(5):524-528
The thermoelastic properties of quasicrystals, possessing 5-th, 8-th, 10-th and 12-th order rotational axes, not characteristic of crystalline bodies, are considered. Using group analysis, canonical representations of the second and fourth rank tensors, characterizing the properties of quasicrystals, are constructed. The fact that orthogonal, decagonal and dodecagonal quasicrystals belong to the class of transversely isotropic materials and the isotropy of icosahedric quasicrystals and fullerenes are proved. 相似文献
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A. Kviklys 《Mechanics of Composite Materials》2000,36(2):143-148
An analytical relationship between the thermooxidation rate constants and mechanical properties of composite materials under
isothermal and dynamic conditions is obtained. With the example of epoxy-based composites, it is shown that the kinetic parameters
of thermooxidation can be used to predict the internal stresses and breakdown voltage of coatings. The calculated drop in
the impact toughness exceeds its experimental value by 30%, while the calculated relative breaking elongation is 1.5–2 times
greater than the experimental one. A considerable decrease in these indices is observed at a loss of 0.1–1 wt.% of volatile
products of thermooxidation.
Submitted to the 11th International Conference on Mechanics of Composite Materials (Riga, June 11–15, 2000).
Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 2, pp. 237–248, January–February, 2000. 相似文献
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The change in the molecular weight of polycaproamide during deformation has been measured. The measurements confirm the breakage of chemical bonds in the course of polymer fracture.Mekhanika Polimerov, Vol. 4, No. 3, p. 562, 1968 相似文献
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O. Costin 《Journal of Differential Equations》2010,249(4):931-2044
We calculate the full asymptotic expansion of boundary blow-up solutions (see Eq. (1) below), for any nonlinearity f. Our approach enables us to state sharp qualitative results regarding uniqueness and radial symmetry of solutions, as well as a characterization of nonlinearities for which the blow-up rate is universal. Lastly, we study in more detail the standard nonlinearities f(u)=up, p>1. 相似文献
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Yu. A. Kashlev 《Theoretical and Mathematical Physics》2006,146(3):430-443
We use methods of nonequilibrium thermodynamics to investigate the quasiequilibrium and kinetic characteristics of channeled
particles regarded as a separate thermodynamic subsystem. For the channeled particles, we derive the energy—momentum balance
equation in the moving coordinate system and show that the solution of the balance equation provides an expression for the
main thermodynamic parameter, the transverse quasitemperature of the channeled-particle subsystem. We study the quasiequilibrium
angular distribution of particles after their passage through a thin single crystal, the quasiequilibrium distribution over
the particle exit angles under backscattering conditions, and also the rate constant for the nonequilibrium (dechanneling)
process at large deviations of the system as a whole from the thermodynamic equilibrium. We discuss a measurement method for
the particle beam transverse temperature over the peak height of the angular particle distribution found in the framework
of a “shoot-through” experiment.
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Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 146, No. 3, pp. 509–524, March, 2006. 相似文献
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Let D be the unit disk in the complex plane with the weighted measure dμβ(z) = (β+1)--π(1-|z|2)βdm(z)(β>-1). Then L2(D,dμβ(z)) = ∞k=0(Aβk Aβk) is the orthogonal direct sum decomposition.In this paper, we define the Hankel and Toeplitz type operators, and study the boundedness, compactness and Sp-criteria for them. 相似文献
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Alexander Yu. Solynin 《Proceedings of the American Mathematical Society》2008,136(2):577-585
Let be analytic on the unit disk with . In 1989, D. Marshall conjectured the existence of the universal constant such that whenever the area, counting multiplicity, of a portion of over is . Recently, P. Poggi-Corradini (2007) proved this conjecture with an unspecified constant by the method of extremal metrics. In this note we show that such a universal constant exists for a much larger class consisting of analytic functions omitting two values of a certain doubly-sheeted Riemann surface. We also find a numerical value, , which is sharp for the problem in this larger class but is not sharp for Marshall's problem.
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