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991.
用直接计算的方法对一类Hamilton系统的两个Abel积分比值的单调性进行讨论,指出该单词性条件可由两个判定函数直接确定. 相似文献
992.
This paper presents an application of real-coded genetic algorithm (RGA) for system identification and controller tuning in process plants. The genetic algorithm is applied sequentially for system identification and controller tuning. First GA is applied to identify the changes in system parameters. Once the process parameters are identified, the optimal controller parameters are identified using GA. In the proposed genetic algorithm, the optimization variables are represented as floating point numbers. Also, cross over and mutation operators that can directly deal with the floating point numbers are used. The proposed approach has been applied for system identification and controller tuning in nonlinear pH process. The simulation results show that the GA based approach is effective in identifying the parameters of the system and the nonlinearity at various operating points in the nonlinear system. 相似文献
993.
Jian-Wen Peng 《Nonlinear Analysis: Theory, Methods & Applications》2009,71(12):6001-6010
In this paper, we introduce a new viscosity approximation scheme based on the extragradient method for finding a common element of the set of solutions to a system of equilibrium problems, the set of fixed points of an infinite family of nonexpansive mappings and the set of solutions to the variational inequality for a monotone, Lipschitz continuous mapping. Several convergence results for the sequences generated by these processes in Hilbert spaces were derived. 相似文献
994.
This paper is concerned with a compact finite difference method for solving systems of two-dimensional reaction–diffusion equations. This method has the accuracy of fourth-order in both space and time. The existence and uniqueness of the finite difference solution are investigated by the method of upper and lower solutions, without any monotone requirement on the nonlinear term. Three monotone iterative algorithms are provided for solving the resulting discrete system efficiently, and the sequences of iterations converge monotonically to a unique solution of the system. A theoretical comparison result for the various monotone sequences is given. The convergence of the finite difference solution to the continuous solution is proved, and Richardson extrapolation is used to achieve fourth-order accuracy in time. An application is given to an enzyme–substrate reaction–diffusion problem, and some numerical results are presented to demonstrate the high efficiency and advantages of this new approach. 相似文献
995.
Automated Storage and Retrieval Systems (AS/RSs) are warehousing systems that are used for the storage and retrieval of products in both distribution and production environments. This paper provides an overview of literature from the past 30 years. A comprehensive explanation of the current state of the art in AS/RS design is provided for a range of issues such as system configuration, travel time estimation, storage assignment, dwell-point location, and request sequencing. The majority of the reviewed models and solution methods are applicable to static scheduling and design problems only. Requirements for AS/RSs are, however, increasingly of a more dynamic nature for which new models will need to be developed to overcome large computation times and finite planning horizons, and to improve system performance. Several other avenues for future research in the design and control of AS/RSs are also specified. 相似文献
996.
A. Meyer Ch. Hofer G. Knapp und G. Tölg 《Fresenius' Journal of Analytical Chemistry》1981,305(1):1-10
Zusammenfassung Es wird eine spezielle Apparatur zur Abtrennung von Selengehalten aus anorganischen ( 0,5 ng/g) und organischen ( 2 ng/g) Matrices beschrieben, die eine zuverlässige Bestimmung der isolierten Selenspuren durch Hydrid-AAS (HG-AAS) bzw. AAS mit elektrothermischer Atomisierung (ETA-AAS) ermöglicht.Beim Aufschluß der Probe im O2- bzw. Ar/O2-Trägergasstrom wird das Selen in einem Quarzsystem als SeO2 verflüchtigt und in einer Vorlage zusammen mit dem Sauerstoff und anderen flüchtigen Substanzen durch Kühlen mit flüssigem Stickstoff kondensiert. Die Leistungsfähigkeit des Verbundverfahrens wird durch zahlreiche Se-Bestimmungen in Metallen, Gesteinen, Sedimenten, Böden, pflanzlichen und tierischen Matrices belegt.
Determination of selenium in the g/g and ng/g range in inorganic and organic matrices by AAS after volatilization in a dynamic system
Summary A special apparatus for the separation of low levels of selenium from inorganic ( 0.5 ng/g) and organic (2 ng/g) matrices is described. It enables a reliable determination of the isolated traces of selenium by hydride-AAS (HG-AAS) or AAS with electrothermal atomisation (ETA-AAS).During decomposition of the sample in a stream of O2 or Ar/O2 in a quartz system, selenium is volatilized as SeO2 that is subsequently trapped simultaneously with oxygen and other volatile substances by cooling with liquid nitrogen. The capability of this multi-stage procedure is proved by numerous determinations of Se in metals, rocks, sediments, soils, plant and animal matrices.
Die Arbeit wurde dankenswerter Weise durch Mittel der Deutschen Forschungsgemeinschaft, Bonn-Bad Godesberg, unterstützt. 相似文献
997.
本文运用正交试验法对东方红 - 40拖拉机液压悬挂系统上拉杆受力因素进行方差分析 ,寻求合理的生产条件 相似文献
998.
Jean-Marc MercierBenedetto Piccoli 《Journal of Differential Equations》2002,180(2):395-426
We consider in this paper the Riemann problem for p-systems of mixed type that define two hyperbolic phases with a stress function satisfying general genuinely nonlinear hypotheses. We describe here all the global Riemann solvers that are continuous for the L1 distance with respect to initial data while conserving the natural symmetry properties of the p-system and coinciding with the Lax solution when defined: these Riemann solvers can be described entirely by a kinetic function, used to select a manifold of subsonic phase transitions and a corresponding set of supersonic phase transitions. 相似文献
999.
THE UNCONDITIONAL STABLE DIFFERENCE METHODS WITH INTRINSIC PARALLELISM FOR TWO DIMENSIONAL SEMILINEAR PARABOLIC SYSTEMS 总被引:2,自引:0,他引:2
GuangweiYuan 《计算数学(英文版)》2003,21(1):63-70
In this paper we are going to discuss the difference schemes with intrinsic parallelism for the boundary value problem of the two dimesional semilinear parabolic systems.The unconditional stability of the general finite difference schemes with intrinsic parallelism is justified in the sense of the continuous dependence of the discrete vector solution of the difference schemes on the discrete data of the original problems in the discrete W2^(2,1) norms.Then the uniqueness of the discrete vector solution of this difference scheme follows as the consequence of the stability. 相似文献
1000.
关于具优势对称部分的不定线性代数方程组的分裂极小残量算法 总被引:5,自引:0,他引:5
1.引 言 考虑大型稀疏线性代数方程组 为利用系数矩阵的稀疏结构以尽可能减少存储空间和计算开销,Krylov子空间迭代算法[1,16,23]及其预处理变型[6,8,13,18,19]通常是求解(1)的有效而实用的方法.当系数矩阵对称正定时,共轭梯度法(CG( 相似文献