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971.
D.Ye. Pivovarov 《Journal of Applied Mathematics and Mechanics》2014,78(2):137-143
The use of the collocation method, with collocation points at the zeroes of a Chebyshev polynomial, to solve spatial problems of the stability of convective flows, is described. The fluid occupies a closed rectangular cavity on the boundaries of which conditions of the first, second and third kind can be specified. Using a differential matrix constructed at the collocation points, the spectral problem is transformed into an extended eigenvector problem that is solved numerically. The Rayleigh problem in a closed layer is solved for different values of the ratio of the sides of the rectangular cavity. The calculations presented are compared with the results of the solution of non-linear equations and also with the experimental and theoretical data of other authors. 相似文献
972.
In this paper, we prove that the 1D Cauchy problem of the compressible Navier–Stokes equations admits a unique global classical solution (ρ,u) if the viscosity μ(ρ)=1+ρβ with β?0. The initial data can be arbitrarily large and may contain vacuum. Some new weighted estimates of the density and velocity are obtained when deriving higher order estimates of the solution. 相似文献
973.
R. Behling A. Fischer M. Herrich A. Iusem Y. Ye 《Computational Optimization and Applications》2014,59(1-2):5-26
The projected Levenberg-Marquardt method for the solution of a system of equations with convex constraints is known to converge locally quadratically to a possibly nonisolated solution if a certain error bound condition holds. This condition turns out to be quite strong since it implies that the solution sets of the constrained and of the unconstrained system are locally the same. Under a pair of more reasonable error bound conditions this paper proves R-linear convergence of a Levenberg-Marquardt method with approximate projections. In this way, computationally expensive projections can be avoided. The new method is also applicable if there are nonsmooth constraints having subgradients. Moreover, the projected Levenberg-Marquardt method is a special case of the new method and shares its R-linear convergence. 相似文献
974.
In this paper, we study a semi-infinite programming (SIP) problem with a convex set constraint. Using the value function of the lower level problem, we reformulate SIP problem as a nonsmooth optimization problem. Using the theory of nonsmooth Lagrange multiplier rules and Danskin’s theorem, we present constraint qualifications and necessary optimality conditions. We propose a new numerical method for solving the problem. The novelty of our numerical method is to use the integral entropy function to approximate the value function and then solve SIP by the smoothing projected gradient method. Moreover we study the relationships between the approximating problems and the original SIP problem. We derive error bounds between the integral entropy function and the value function, and between locally optimal solutions of the smoothing problem and those for the original problem. Using certain second order sufficient conditions, we derive some estimates for locally optimal solutions of problem. Numerical experiments show that the algorithm is efficient for solving SIP. 相似文献
975.
在本文中, 我们主要讨论了广义Cox模型的信息流扩大问题.
假设在市场中有两类投资者, 第一类投资者拥有市场信息,
这里由一个维的布朗运动和一个可积随机
测度驱动; 而第二类投资者具有扩大的信息流,
这里假设是由信息流和广义Cox的模型刻画的违约信息流生成.
我们建立和刻画了广义Cox模型并且求给出它的主要性质包括生存过程和违约条件密度.
与Cox模型显著区别的是, 如果违约由广义Cox模型模型刻画, 与Cox模型平凡的结果不同的是,
鞅的分解更复杂和具有一般性. 相似文献
976.
977.
n this paper, we present an inexact inverse subspace iteration method for computing a few eigenpairs of the generalized eigenvalue problem Ax=λBx. We first formulate a version of inexact inverse subspace iteration in which the approximation from one step is used as an initial approximation for the next step. We then analyze the convergence property, which relates the accuracy in the inner iteration to the convergence rate of the outer iteration. In particular, the linear convergence property of the inverse subspace iteration is preserved. Numerical examples are given to demonstrate the theoretical results. 相似文献
978.
Mert Kılınç Gaye Ö. Çakal Sertan Yeşil Göknur Bayram İnci Eroğlu Saim Özkar 《Journal of Crystal Growth》2010,312(22):3361-3366
Synthesis of zinc borate was conducted in a laboratory and a pilot scale batch reactor to see the influence of process variables on the reaction parameters and the final product, 2ZnO·3B2O3·3.5H2O. Effects of stirring speed, presence of baffles, amount of seed, particle size and purity of zinc oxide, and mole ratio of H3BO3:ZnO on the zinc borate formation reaction were examined at a constant temperature of 85 °C in a laboratory (4 L) and a pilot scale (85 L) reactor. Products obtained from the reaction in both reactors were characterized by chemical analysis, X-ray diffraction, particle size distribution analysis, thermal gravimetric analysis and scanning electron microscopy. The kinetic data for the zinc borate production reaction was fit by using the logistic model. The results revealed that the specific reaction rate, a model parameter, decreases with increase in particle size of zinc oxide and the presence of baffles, but increases with increase in stirring speed and purity of zinc oxide; however, it is unaffected with the changes in the amount of seed and reactants ratio. The reaction completion time is unaffected by scaling-up. 相似文献
979.
Yong Mei Hu Guang Hai Su Stephen Cho‐Wing Sze Wencai Ye Yao Tong 《Biomedical chromatography : BMC》2010,24(4):438-453
A simple method based on liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (LC‐DAD‐ESI‐MS) was developed for the quality assessment of Cortex Phellodendri (CP), which was mainly derived from two species of Phellodendron chinense Schneid and Phellodendron amurense Rupr. Total 41 compounds, including 14 phenols, 24 alkaloids and three liminoidal triterpenes were identified or tentatively characterized from the 75% methanol extract of CP samples by online ESI‐MSn fragmentation and UV spectra analysis. Among them, two phenols and six alkaloids were simultaneously quantified using HPLC‐DAD method. The validated HPLC‐DAD method showed a good linearity, precision, repeatability and accuracy for the quantification of eight marker compounds. Furthermore, the plausible fragmentation pathway of the representative compounds were proposed in the present study. The differences of the chemical constituents content and the comprehensive HPLC profiles between the two CP species using LC‐DAD‐ESI‐MS method are reported for the first time, indicating that the CP drugs from different resources should be used separately in the clinic. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
980.