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111.
Es wurde eine unter Betriebsverhältnissen anwendbare Prüfmethode für die Bestimmung der Verschleβeigenschaften von Verbrennungsmotoren mit Hilfe der Gammaspektrometrie der neutronenaktivierten Verschleiβprodukte ausgearbeitet und die die Lebensdauer begrenzende Wirkung des abrasiven Verschleiβes festgestellt. Durch Verbesserung der Luftfilterung konnte die potentielle Lebensdauer der Motoren gut angenähert, und es konnten die Verunreinigung des Schmieröls vermindert und die Dauer der Ölwechselperiode verdoppelt werden. 相似文献
112.
The effect of an applied stress on the annealing texture of polyethylene is demonstrated by means of stress annealing experiments. Cold-drawn polyethylene specimens were annealed for various times at 126°C with and without a compression stress of 0.4 kg/mm2 normal to the drawing direction. The observed change in the annealing texture resulting from the compression stress indicates that stress-induced alignment of the crystalline regions in the polyethylene occurs (stress-induced texture). The alignment may be understood in terms of the elastic energy stored in the material during annealing. The stored elastic energy is minimized by aligning the crystallites such that the crystallographic direction of lowest modulus is parallel to the direction of the applied stress. The importance of this observation for the interpretation of the high-temperature deformation textures of polymers is discussed. 相似文献
113.
This article deals with the critical curve of a fast diffusive polytropic filtration system coupled at the boundary condition. By constructing the self-similar supersolution and subsolution, we obtain the critical global existence curve. The critical curve of Fujita type is conjectured with the aid of some new results. 相似文献
114.
A new family of finite-dimensional simple modular Lie superalgebra ? is constructed based on results of Y. Z. Zhang and Q. C. Zhang [J. Algebra, 2009, 321: 3601–3619]. The simplicity and generators of ? are discussed and the derivation superalgebra of ? is characterized. Furthermore, the invariance of the nonnatural filtration of ? is determined by the method of minimal dimension of image spaces. 相似文献
115.
This article studies the theory of discrete-time backward stochastic differential equations (also called BSDEs) with a random terminal time, which is not a stopping time. We follow Cohen and Elliott [2] and consider a reference filtration generated by a general discrete-time finite-state process. The martingale representation theorem for essentially bounded martingales under progressively enlarged filtration is established. Then we prove the existence and uniqueness theorem of BSDEs under enlarged filtration using some weak assumptions of the driver. We also present conditions for a comparison theorem. Applications to nonlinear expectations and optimal design of dynamic default risk are explored. 相似文献
116.
Let G be a connected graph and D(G) be its distance matrix. In this article, the Smith normal forms of the integer matrices D(G) are determined for trees, wheels, cycles, complements of cycles and are reduced for complete multipartite graphs. 相似文献
117.
Let G be a simple connected graph and L(G) be its Laplacian matrix. In this note, we prove that L(G) is congruent by a unimodular matrix to its Smith normal form if and only if G is a tree. 相似文献
118.
Pentti Haukkanen 《Linear and Multilinear Algebra》2013,61(3):301-309
Considering lower closed sets as closed sets on a preposet (P, ≤), we obtain an Alexandroff topology on P. Then order preserving functions are continuous functions. In this article we investigate order preserving properties (and thus continuity properties) of integer-valued arithmetical functions under the usual divisibility relation of integers and power GCD matrices under the divisibility relation of integer matrices. 相似文献
119.
In this paper, instead of energy methods, we apply the supersolution and subsolution methods to investigate the critical extinction exponents for a polytropic filtration equation with absorption and source, and improve the results of Mu et al. (J. Math. Anal. Appl. 2012; 391 :429–440). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
120.
Abstract Let A be a commutative ring with identity, let X, Y be indeterminates and let F(X,Y), G(X, Y) ∈ A[X, Y] be homogeneous. Then the pair F(X, Y), G(X, Y) is said to be radical preserving with respect to A if Rad((F(x, y), G(x, y))R) = Rad((x,y)R) for each A-algebra R and each pair of elements x, y in R. It is shown that infinite sequences of pairwise radical preserving polynomials can be obtained by homogenizing cyclotomic polynomials, and that under suitable conditions on a ?-graded ring A these can be used to produce an infinite set of homogeneous prime ideals between two given homogeneous prime ideals P ? Q of A such that ht(Q/P) = 2. 相似文献