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41.
We solve the modified Dirac equation by adding a harmonic oscillator potential and implementing the Nikiforov–Uvarov technique. The closed forms of solutions are reported in a quite simple and systematic manner. 相似文献
42.
Orfeu Bertolami 《General Relativity and Gravitation》2008,40(9):1891-1898
We propose a Curvature Principle to describe the dynamics of interacting universes in a multi-universe scenario and show,
in the context of a simplified model, how interaction drives the cosmological constant of one of the universes toward a vanishingly
small value. We also conjecture on how the proposed Curvature Principle suggests a solution for the entropy paradox of a universe
where the cosmological constant vanishes.
Essay selected for an honorable mention by the Gravity Research Foundation, 2007. 相似文献
43.
Anatoli Andrei Vankov 《Foundations of Physics》2008,38(6):523-545
In relativistic theories, the assumption of proper mass constancy generally holds. We study gravitational relativistic mechanics
of point particle in the novel approach of proper mass varying under Minkowski force action. The motivation and objective
of this work are twofold: first, to show how the gravitational force can be included in the Special Relativity Mechanics framework,
and, second, to investigate possible consequences of the revision of conventional proper mass concept (in particular, to clarify
a proper mass role in the divergence problem). It is shown that photon motion in the gravitational field can be treated in
terms of massless refracting medium, what makes the gravity phenomenon compatible with SR Mechanics framework in the variable
proper mass approach.
Specifically, the problem of point particle in the spherical symmetric stationary gravitational field is studied in SR-based
Mechanics, and equations of motion in the Lorentz covariant form are obtained in the relativistic Lagrangean problem formulation.
The dependence of proper mass on potential field strength is derived from the Euler-Lagrange equations as well. One of new
results is the elimination of conventional 1/r divergence, which is known to be not removable in Schwarzschild gravitomechanics. Predictions of particle and photon gravitational
properties are in agreement with GR classical tests under weak-field conditions; however, deviations rise with potential field
strength. The conclusion is made that the approach of field-dependent proper mass is perspective for development of SR gravitational
mechanics and further studies of gravitational problems. 相似文献
44.
45.
The creep behavior of PMMA immersed in liquid scintillator at room temperature was experimentally studied with a new type of creep test machine. Both short-term and creep-rupture tensile tests at eight stress levels were performed. A master curve of creep compliance at a reference stress was obtained according to the Time-Stress Superposition Principle. The master curve was compared with the actual long-term creep curve. It demonstrates that the two curves coincide well at short times. However, the actual creep data shows a higher creep rate as time goes on. The actual lifetime is much shorter than that predicted by the master curve. Furthermore, the relationship between long-term creep limited strength and service life was determined. The results can be used to guide the safety design of PMMA vessels for application in a neutrino observatory. 相似文献
46.
47.
Andrey Bovykin 《Proceedings of the American Mathematical Society》2007,135(9):2967-2973
For every and every function of one argument, we introduce the statement : ``for all , there is such that for any set of rational numbers, there is of size such that for any two -element subsets and in , we have We prove that for and any function eventually dominated by , the principle is not provable in . In particular, the statement is not provable in Peano Arithmetic. In dimension 2, the result is: does not prove , where and is the inverse of the Ackermann function.
48.
49.
Vladimir V. Anisimov 《TOP》1999,7(2):169-186
Some special classes of Switching Processes such as Recurrent Processes of a Semi-Markov type and Processes with Semi-Markov
Switches are introduced. Limit theorems of Averaging Principle and Diffusion Approximation types are given. Applications to
the asymptotic analysis of overloading state-dependent Markov and semi-Markov queueing modelsM
SM,Q
/M
SM,Q
/1/∞ and retrial queueing systemsM/G/1/w.r in transient conditions are studied.
The paper was supported by INTAS Project 96-0828 相似文献
50.