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991.
Xiao-Sen Li Yu Zhang Gang Li Zhao-Yang Chen Ke-Feng Yan Qing-Ping Li 《The Journal of chemical thermodynamics》2008,40(9):1464-1474
We employ two thermodynamic approaches, based on the equal fugacities and the equal activities, to predict the gas hydrate equilibrium dissociation conditions in the porous media. The predictions are made for the hydrate systems, CH4/H2O, C2H6/H2O, C3H8/H2O, CO2/H2O, CH4/CO2/H2O, C3H8/CH4/C2H6/H2O, and CH4/CH3OH/H2O. For the non-hydrate phase, we used the Trebble–Bishnoi equation in the fugacity approach and the Soave–Redlich–Kwong equation in the activity approach. For the hydrate phase, the van der Waals–Platteeuw model incorporated with the capillary model of Llamedo et al. [M. Llamedo, R. Anderson, B. Tohidi, Am. Mineral. 89 (2004) 1264–1270] was used in the two approaches. The predictions are found to be in satisfactory to good agreement with the experimental data. The predictive ability of the fugacity approach is better than that of the activity approach. 相似文献
992.
In noise abatement using porous or fibrous materials, accurate determination of the surface impedance representing the absorber is decisive for simulation quality. The presence of grazing flow and non-homogeneous ambient temperature influence the reaction of the absorber and may suitably be included in a modified “effective” surface impedance. In this paper, this approach is applied to a generic case representative for the engine bay of a heavy truck, where porous shields suppress the radiated noise, e.g. during a pass-by noise test. The change in the absorption is determined numerically by solving the wave propagation through a layer of varying temperature and flow adjacent to the impedance surface for different angles of incidence. The study shows significant impact of both flow and temperature, especially for materials with low absorption. The diffuse field absorption coefficient is also derived and although the effect is less pronounced in this case, it is still important in lower frequencies and in the frequency range typical for IC engine noise. The proposed numerical method is shown to be accurate and efficient for determination of the effective impedance and moreover not limited to thin boundary layers. 相似文献
993.
In this paper, we deal with constraint qualifications, stationary concepts and optimality conditions for a nonsmooth mathematical program with equilibrium constraints (MPEC). The main tool in our study is the notion of convexificator. Using this notion, standard and MPEC Abadie and several other constraint qualifications are proposed and a comparison between them is presented. We also define nonsmooth stationary conditions based on the convexificators. In particular, we show that GS-stationary is the first-order optimality condition under generalized standard Abadie constraint qualification. Finally, sufficient conditions for global or local optimality are derived under some MPEC generalized convexity assumptions. 相似文献
994.
Mostafa Nasri 《Optimization》2016,65(2):467-478
The analysis of the principal-agent problem usually requires the classical first-order approach (FOA). However, the validity of the FOA makes restrictive assumptions on the problem under consideration such as the convexity of the distribution function condition. The main aim of this paper is to compute the optimal wages and characterize a closed form solution to the risk-neutral principal-agent problem with limited liability constraints. The development in this paper mainly invokes certain techniques in the semi-infinite programming rather than the FOA. 相似文献
995.
Jonáš Volek 《Journal of Difference Equations and Applications》2016,22(11):1698-1719
We study the existence and uniqueness for discrete Neumann and periodic problems. We consider both ordinary and partial difference equations involving sublinear perturbations. All the proofs are based on reformulating these discrete problems as a general singular algebraic system. Firstly, we use variational techniques (specifically, the Saddle Point Theorem) and prove the existence result based on a type of Landesman–Lazer condition. Then we show that for a certain class of bounded nonlinearities this condition is even necessary and therefore, we specify also the cases in which there does not exist any solution. Finally, the uniqueness is discussed. 相似文献
996.
Global behavior of solutions to the fast diffusion equation with boundary flux governed by memory 下载免费PDF全文
Jeffrey R. Anderson Keng Deng Qian Wang 《Mathematical Methods in the Applied Sciences》2016,39(15):4451-4462
We study global existence and blow up in finite time for a one‐dimensional fast diffusion equation with memory boundary condition. The problem arises out of a corresponding model formulated from tumor‐induced angiogenesis. We obtain necessary and sufficient conditions for global existence of solutions to the problem. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
997.
Dongbing Zha 《Mathematical Methods in the Applied Sciences》2016,39(15):4484-4495
In this paper, we give an alternative proof to the global existence result, which is originally owing to the pioneering work of Klainerman and Christodoulou, for the Cauchy problem of quasilinear wave equations with null condition in three space dimensions. The proof can display the following three features simultaneously: the Lorentz boost operator is not employed in the generalized energy estimates; the generalized energy of the solution will be always small, which was first observed by Alinhac; and the initial data are not assumed to have a compact support. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
998.
Chang‐Hua Wei 《Mathematical Methods in the Applied Sciences》2016,39(15):4563-4583
This paper investigates the smooth solution of 2D Chaplygin gas equations on an asymptotically flat Riemannian manifold. Under the assumption that the initial data are close to a constant state and the vorticity of the initial velocity vanishes, we prove the global existence of smooth solutions to the Cauchy problem for two‐dimensional flow of Chaplygin gases on curved space. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
999.
To a system of closed one‐forms on the torus, we associate a differential complex and compute the induced cohomology groups provided that a related matrix satisfies a Diophantine condition. 相似文献
1000.
Yuji Liu 《Journal of Mathematical Analysis and Applications》2007,327(2):801-815
Sufficient conditions for the existence of at least one T-periodic solution of nonlinear functional difference equation
Δx(n)+a(n)x(n)=f(n,u(n)), 相似文献