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Aref Jeribi Hatem Megdiche Nedra Moalla 《Mathematical Methods in the Applied Sciences》2005,28(2):127-145
This paper deals with Rotenberg's models of cell populations with general boundary conditions. It is shown, first, that the associated Cauchy problem is governed by a C0‐semigroup. Second, we have proved that if the boundary operator is positive, the transport semigroup is irreducible. And finally, a spectral decomposition of the solution into an asymptotic term was derived. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
23.
W.S. Barham A.J. Aref G.F. Dargush 《International Journal of Solids and Structures》2005,42(26):6586-6609
The displacement-based finite element method dominates current practice for material nonlinear analysis of structures. However, there are several characteristics that may limit the effectiveness of this approach. In particular, for elastoplastic analysis, the displacement method relies upon a step-by-step incremental approach stemming from flow theory and also requires significant mesh refinement to resolve behavior in plastic zones. This leads to computational inefficiencies that, in turn, encourage the reconsideration of force-based approaches for elastoplastic problems.One of these force algorithms that has been recently developed is the large increment method. The main advantage of the flexibility-based large increment method (LIM) over the displacement method is that it separates the global equilibrium and compatibility equations from the local constitutive relations. Consequently, LIM can reach the solution in one large increment or in a few large steps, thus, avoiding the development of cumulative errors. This paper discusses the extension of the large increment methodology for the nonlinear analysis of plane frame structures controlled by an elastic, perfectly plastic material model. The discussion focuses on the power of LIM to handle these nonlinear problems, especially when plastic hinges form in the frame and ultimately as the structure approaches the collapse stage. Illustrative planar frame examples are presented and the results are compared with those obtained from a standard displacement method. 相似文献
24.
I. Ya. Aref’eva G. S. Djordjevic A. Yu. Khrennikov S. V. Kozyrev Z. Rakic I. V. Volovich 《P-Adic Numbers, Ultrametric Analysis, and Applications》2017,9(1):82-85
We present a brief review of some parts of p-adic mathematical physics related to the scientific work of Branko Dragovich on the occasion of his 70th birthday. 相似文献
25.
Nowadays low-cost RFID systems have moved from obscurity into mainstream applications which cause growing security and privacy concerns. The lightweight cryptographic primitives and authentication protocols are indispensable requirements for these devices to grow pervasive. In recent years, there has been an increasing interest in intuitive analysis of RFID protocols. This concept has recently been challenged by formal privacy models. This paper investigates how to analyse and solve privacy problems in formal model. First, we highlight some vague drawbacks especially in forward and backward traceability analysis and extend it in the simulation-based privacy model family. Then, the privacy weaknesses of three new-found RFID authentication protocols are analysed in formal privacy models and three improved protocols are proposed to prevent the aforementioned attacks. 相似文献
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27.
An efficient tissue culture technology has been designed for mass multiplication of Nyctanthes arbor-tristis L. by preculturing nodal explants in thidiazuron (TDZ)-supplemented liquid Murashige and Skoog (MS) media. Direct inoculation
of nodal segments on semi-solid MS medium augmented with various concentrations of TDZ (0.1 to 0.9 μM) produced shoots but
with low regeneration response and few shoots per explant. Hence, nodal explants were pretreated with greater concentrations
of TDZ (5 to 100 μM) in liquid MS media for different durations (4, 8, 12, and 16 days) with the aim of improving shoot regeneration
response from cultured explants. After pretreatment, explants were transferred to agar-solidified hormone-free MS medium.
Best response in terms of percent regeneration (94%), number of shoots per explant (20.00 ± 1.15), and greatest shoot length
(7.23 ± 0.83 cm) were obtained with nodal segments pretreated in75 μM TDZ for 8 days. Similarly, root induction was obtained
from pulse-treated microshoots for 24 h with 200 μM indole-3-butyric acid (IBA) followed by their transfer to 1/2 MS medium
which produced an average of 5.50 ± 0.92 roots per microshoot. The rooted plantlets were transplanted to soil with 80% success
rate. 相似文献
28.
Theoretical and Mathematical Physics - We study spatial Wilson loops for a fully anisotropic background metric supported by the Einstein action with a dilaton field and three Maxwell tensors. We... 相似文献
29.
A model of a shielded asymmetric two-slot transmission line is constructed on the basis of the method of almost total inversion
of the integral operator. In the case of symmetric location of the slots, the boundary-value problem for the given structure
is reduced to two independent systems of integral equations corresponding to different types of natural waves. The results
of numerical computation of the dispersion characteristics and distributions of tangential components of the electric field
intensity on the slots are given.
Povolzhskii Institute of Informatics and Communication, Samara; Institute of Radio Engineering and Electronics, Russian Academy
of Sciences, Moscow, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 4, pp. 507–518,
April, 1998. 相似文献
30.
In this article, we give a characterization of a class of bounded Fredholm operators on a Banach space which is developed to present some general existence results of the operators equation of the second kind. The obtained results are used to describe the Riesz–Schauder theory of compact operators in the more general setting of polynomially compact operators. 相似文献