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991.
992.
V. V. Ilyasov 《Russian Physics Journal》1997,40(6):574-578
An analysis is made of the thermodynamic stability of the dislocation structure in polycrystalline samples of Fe-C, deformed
under conditions of high rates and hydrostatic pressures, based on experimental and theoretical data concerning the internal
energy and on diffractometer measurements of the broadening of x-ray lines. The method of deformation calorimetry was used
to determine the internal energy in a wide range of deformations. A theoretical model is proposed for estimating the change
in internal energy in deformed alloys. An investigation is made of the dependence of the interdislocation interaction parameter
on the deformation rate for different stressed state-schemes and large plastic deformations. It is shown that the relative
quantity δU/A is correlated in a wide range of deformations with the relative root-mean-square distortions of the crystal lattice of the
deformed solid solution. The mechanisms for the accumulation of energy in deformed solid solutions having a body-centered
cubic lattice are considered.
Don State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 77–83. 相似文献
993.
It is shown that equations describing the dynamics of Darwinian systems (DS) far from the bifurcation points may be expressed
in Hamiltonian form. The cases of DS with constant organization and DS with a constant flux through the system are considered.
The configurational part of phase space is formed by variables containing information on the structure of the system. Momentum
variables may be regarded as specific rates of multiplication. The evolution of DS with constant organization in this phase
space is expressed as uniform rectilinear motion. In the case of DS with a constant flux, the motion occurs in some effective
constant and uniform field. The meaning of the elements of the Hamiltonian structure is described in terms of theoretical
biology.
Tomsk State University. Scientific-Research Institute of Biological Systems, Tomsk State University. Translated from Izvestiya
Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 23–28, July, 1997. 相似文献
994.
有势场逆问题的边界元法 总被引:5,自引:0,他引:5
本文给出了位势方程逆问题的一种最小二乘边界元解法。控制方程为Laplace方程,但一部分边界上未给出任何边值,而只在某些内点上给出了势函值。这一问题在数学上属不适定问题,但在一定条件下存在唯一解。本文同时给出了一种估计解的可靠性的方法。数值试验表明,这类逆问题采用边界元法是非常有效的。 相似文献
995.
996.
Elizabeth S. Senger 《School science and mathematics》1997,97(3):139-149
Thirteen fifth graders were given an assignment to invent their own numeration systems, following a unit on bases and a look at early events in the history of numbers. The task presented options that required the students to make decisions (such as whether to use a base, which base to use, design of symbols, etc.), and build a rationale for the elements of their system. Analyses of patterns embedded in their invented systems provided an assessment of student understanding of numeration. The progression of more and less complex thinking related to the student's choice of a base other than 10, consistency of logic throughout the system in words and symbols, rationale for change, and perception of real life examples that would change if the system was adopted. The invention task is presented as another way to make connections. 相似文献
997.
998.
999.
1000.
I.K. Argyros 《Applied Mathematics Letters》1997,10(6):21-28
In this note, we use inexact Newton-like methods to find solutions of nonlinear operator equations on Banach spaces with a convergence structure. Our technique involves the introduction of a generalized norm as an operator from a linear space into a partially ordered Banach space. In this way, the metric properties of the examined problem can be analyzed more precisely. Moreover, this approach allows us to derive from the same theorem, on the one hand, semilocal results of Kantorovich-type, and on the other hand, global results based on monotonicity considerations. By imposing very general Lipschitz-like conditions on the operators involved, on the one hand, we cover a wider range of problems, and on the other hand, by choosing our operators appropriately, we can find sharper error bounds on the distances involved than before. Furthermore, we show that special cases of our results reduce to the corresponding ones already in the literature. Finally, several examples are being provided where our results compare favorably with earlier ones. 相似文献