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991.
It is discussed in this paper that under what conditions, for a continuous domain L, there is a Scott continuous self-mapping f : L → L such that the set of fixed points fix(f) is not continuous in the ordering induced by L. For any algebraic domain L with a countable base and a smallest element, the problem presented by Huth is partially solved. Also, an example is given and shows that there is a bounded complete domain L such that for any Scott continuous stable self-mapping f, fix(f) is not the retract of L. 相似文献
992.
In this paper,on the basis of the theories and methods of ecology and ordinary differential equations,an ecological model with an impulsive control strategy is established.By using the theories of impulsive equations,small amplitude perturbation skills and compar-ison technique,we get the condition which guarantees the global asymptotical stability of the prey-x-eradication and predator-y-eradication periodic solution.It is proved that the system is permanent.Furthermore,numerical simulations are also illustrated which agree well with our theoretical analysis.All these results may be useful in study of the dynamic complexity of ecosystems. 相似文献
993.
We discuss the Lagrangian transport in a time-dependent oceanic system involving a Lagrangian barrier associated with a salinity front which interacts intermittently with a set of Lagrangian eddies — ‘leaky’ coherent structures that entrain and detrain fluid as they move. A theoretical framework, rooted in the dynamical systems theory, is developed in order to describe and analyse this situation. We show that such an analysis can be successfully applied to a realistic ocean model. Here, we use the output of the numerical ocean model DieCAST from Dietrich et al. (2004) [17] and Fernández et al. (2005) [18] studied earlier in Mancho et al. (2008) [15] where a Lagrangian barrier associated with the North Balearic Front in the North-Western Mediterranean Sea was identified. The numerical model provides an Eulerian view of the flow and we employ the dynamical systems approach to identify relevant hyperbolic trajectories and their stable and unstable manifolds. These manifolds are used to understand the Lagrangian geometry of the evolving front-eddy system. Transport in this system is effected by the turnstile mechanism whose spatio-temporal geometry reveals intermittent pathways along which transport occurs. Particular attention is paid to the ‘Lagrangian’ interactions between the front and the eddies, and to transport implications associated with the transition between the one-eddy and two-eddy situation. The analysis of this ‘Lagrangian’ transition is aided by a local kinematic model that provides insight into the nature of the change in hyperbolic trajectories and their stable and unstable manifolds associated with the ‘birth’ and ‘death’ of leaky Lagrangian eddies. 相似文献
994.
研究了Lévy稳定噪声激励下的双稳Duffing-van der Pol振子,利用Monte Carlo方法,得到了振幅的稳态概率密度函数.分析了Lévy稳定噪声的强度和稳定指数对概率密度函数的影响,通过稳态概率密度的性质变化,讨论了噪声振子的随机分岔现象,发现了不仅系统参数和噪声强度可以视为分岔参数,Lévy噪声的稳定指数 α 的改变也能诱导系统出现随机分岔现象.
关键词:
Lévy稳定噪声
Duffing-van der Pol振子
稳态概率密度函数
随机分岔 相似文献
995.
R. Kumar Johnsy George R. Rajamanickam S. Nataraju S.N. Sabhapathy A.S. Bawa 《Radiation Physics and Chemistry》2011,80(12):1448-1450
Effect of irradiation in combination with retort processing on the shelf life and safety aspects of an ethnic Indian food product like vegetable pulav was investigated. Gamma irradiation of RTE vegetable pulav was carried out at different dosage rates with 60Co followed by retort processing. The combination processed samples were analysed for microbiological, chemical and sensory characteristics. Microbiological analysis indicated that irradiation in combination with retort processing has significantly reduced the microbial loads whereas the chemical and sensory analysis proved that this combination processing is effective in retaining the properties even after storage for one year at ambient conditions. The results also indicated that a minimum irradiation dosage at 4.0 kGy along with retort processing at an F0 value of 2.0 is needed to achieve the desired shelf life with improved organoleptic qualities. 相似文献
996.
997.
998.
《代数通讯》2013,41(6):1709-1732
ABSTRACT The generic initial ideals of a given ideal are rather recent invariants. Not much is known about these objects,and it turns out to be very difficult to compute them. The main purpose of this paper is to study the behaviour of generic initial ideals with respect to the operation of taking distractions. Theorem 4.3 is our main result. It states that the DegRevLex -generic initial ideal of the distraction of a strongly stable ideal is the ideal itself. In proving this fact, we develop some new results related to distractions, stable and strongly stable ideals. We draw some geometric conclusions for ideals of points. 相似文献
999.
In this article, we study stability of minimal fibers and integrability of horizontal distribution for horizontally conformal maps and harmonic morphisms. Let be a horizontally conformal submersion. We prove that if the horizontal distribution is integrable, then any minimal fiber of φ is volume‐stable. This result is an improved version of the main theorem in [15]. As a corollary, we obtain if φ is a submersive harmonic morphism whose fibers are totally geodesic, and the horizontal distribution is integrable, then any fiber of φ is volume‐stable and so such a map φ is energy‐stable if M is compact. We also show that if is a horizontally conformal map from a compact Riemannian manifold M into an orientable Riemannian manifold N which is horizontally homothetic, and if the pull‐back of the volume form of N is harmonic, then the horizontal distribution is integrable and φ is a harmonic morphism. 相似文献
1000.