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91.
92.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(9):2974-2982
For some abstract classes of nonlinear non-autonomous systems with variable and state-dependent delays existence, non-existence and multiplicity of periodic solutions are discussed. To illustrate the efficiency of the method, we obtain some well-known results for applied systems as corollaries of our existence theorems. 相似文献
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95.
Linhe Zhu Xiaoyuan Huang Ying Liu Zhengdi Zhang 《Journal of Mathematical Analysis and Applications》2021,493(2):124539
In the new social media era, it is becoming increasingly important to explore the propagation rules for rumors in social networks. This article is concerned with investigating a diffusive susceptible-infected rumor propagation model with a nonlinear propagation function in a spatially heterogeneous environment. We establish the uniform persistence and analyze the asymptotic behavior of the rumor-spreading steady state for the spatially heterogeneous model when one of the diffusion coefficients tends to zero. Moreover, to better reflect the effect of a time delay on the process of rumor propagation, we establish a spatially homogeneous model with a time delay and prove the existence and local stability of the corresponding equilibrium point. Furthermore, the optimal control in the spatially homogeneous environment case is derived. Finally, several numerical simulations are performed to verify the theoretical results in both spatially heterogeneous and spatially homogeneous systems. 相似文献
96.
In this article we propose a stage-structured predator–prey model with disturbing pulse and time delays and obtain the sufficient conditions for the global attractivity of predator-eradiation periodic solution and permanence of the system. We also show that time delay, pulse catching rate and the period of pulsing can affect the dynamics of the system. 相似文献
97.
Uri. Goldberg 《International Journal of Computational Fluid Dynamics》2013,27(1):27-38
A new topography-parameter-free turbulence closure, based on a transport equation for the pseudo eddy viscosity, is described. The model is tested against experimental data of several flow cases across the Mach number range and compared to Menter's single equation model and to the Spalart-Allmaras model. The main conclusion is that the new closure outperforms the other two models in both low and high speed flows. 相似文献
98.
Humberto Hinojosa-GómezAuthor Vitae J. Fernando Barragán-ArocheEnrique R. Bazúa-RuedaAuthor Vitae 《Fluid Phase Equilibria》2010
In this work we present two modifications to the Peng–Robinson-Fitted equation of state where pure component parameters are regressed to vapor pressure and saturated liquid density data. The first modification (PR-f-mod) is a method that enhances the equation of state pure component property predictions through simple temperature dependent pure component parameters. In the second modification (PR-f-prop) we propose a temperature dependency for co-volume b in the repulsive parameter of the EoS, and revise the temperature function in the attractive term. The agreement with experimental data for 72 pure substances, including highly polar compounds, is remarkably good. We obtain average absolute deviations in saturated liquid density of less than 1% for all substances studied. 相似文献
99.
The allocation of cost savings is very important for the success of the joint relationship between the buyer and vendor in supply chain management. This paper develops integrated models with permissible delay in payments for determining the optimal replenishment time interval and replenishment frequency. In addition, the variant pricing strategy is employed to obtain both sides’ cost savings in order to entice buyers to join long-term cooperative relationships. A simple solution algorithm is presented to allocate the cost savings in the integration model, and a numerical example is used to demonstrate the feasibility of the proposed integration models. 相似文献
100.
Using a similar approach as Lencka and Anderko [AIChE J. 39 (1993) 533], we developed an equation of state for hydrogen fluoride (HF), which can correlate the vapor pressure, the saturated liquid and vapor densities of it from the triple point to critical point with good accuracy. We used an equilibrium model to account for hydrogen bonding that assumes the formation of dimer, hexamer, and octamer species as suggested by Schotte [Ind. Eng. Chem. Process Des. Dev. 19 (1980) 432]. The physical and chemical parameters are obtained directly from the regression of pure component properties by applying the critical constraints to the equation of state for hydrogen fluoride. This equation of state together with the Wong–Sandler mixing rule as well as the van der Waals one-fluid mixing rule are used to correlate the phase equilibria of binary hydrogen fluoride mixtures with HCl, HCFC-124, HFC-134a, HFC-152a, HCFC-22, and HFC-32. For these systems, new equation of state with the Wong–Sandler mixing rule gives good results. 相似文献