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31.
From the linear Vlasov equation,the theoretical investigation on relativistic backward wave osciUator is performed.The relationship between the microwave power and the guiding magnetic field,which accords with the results of the particle simulation and experiments,is deduced. 相似文献
32.
在已有的众多准等熵加载技术中,磁驱动准等熵加载技术具有准等熵程度高、压力范围大、实验材料种类多、效费比高等特点。利用中物院流体物理研究所建成的磁驱动准等熵压缩和高速飞片实验装置CQ-1.5(最高加载压力为50GPa),成功开展了45钢的准等熵压缩实验,对装置的主要参数进行了介绍;利用激光干涉测试系统DPS获得了45钢飞片的自由面速度历史,通过反积分处理给出了材料准等熵压缩的p-V关系。通过分析实验数据,获得了45钢3种形式的等熵方程的参数。实验获得的最高等熵压力为47.5GPa。 相似文献
33.
34.
In this article, we investigate Programming Evaluation and Review Technique networks with independently and generally distributed activity durations. For any path in this network, we select all the activities related to this path such that the completion time of the sub-network (only consisting of all the related activities) is equal to the completion time of this path. We use the elapsed time as the supplementary variables and model this sub-network as a Markov skeleton process, the state space is related to the subnetwork structure. Then use the backward equation to compute the distribution of the sub-network's completion time, which is an important rule in project management and scheduling. 相似文献
35.
This article presents the study of singularly perturbed parabolic reaction–diffusion problems with boundary layers. To solve these problems, we use a modified backward Euler finite difference scheme on layer adapted nonuniform meshes at each time level. The nonuniform meshes are obtained by equidistribution of a positive monitor function, which involves the second-order spatial derivative of the singular component of the solution. The equidistributing monitor function at each time level allows us to use this technique to non-linear parabolic problems. The truncation error and the stability analysis are obtained. Parameter–uniform error estimates are derived for the numerical solution. To support the theoretical results, numerical experiments are carried out. 相似文献
36.
A. Y. Lee 《Journal of Optimization Theory and Applications》1988,57(3):519-536
Neighboring extremals of dynamic optimization problems with path equality constraints and with an unknown parameter vector
are considered in this paper. With some simplifications, the problem is reduced to solving a linear, time-varying two-point
boundary-value problem with integral path equality constraints. A modified backward sweep method is used to solve this problem.
Two example problems are solved to illustrate the validity and usefulness of the solution technique.
This research was supported in part by the National Aeronautics and Space Administration under NASA Grant No. NCC-2-106.
The author is indebted to Professor A. E. Bryson, Jr., Department of Aeronautics and Astronautics, Stanford University, for
many stimulating discussions. 相似文献
37.
Energy conservation of numerical integrators is well understood for symplectic one-step methods. This article provides new insight into energy conservation with non-symplectic methods. Sufficient conditions and counter-examples are presented.
AMS subject classification (2000) 65L06, 65P10, 37J99.Submitted June 2004. Accepted October 2004. Communicated by Syvert Nørsett. 相似文献
38.
Mechthild Thalhammer 《BIT Numerical Mathematics》2004,44(2):343-361
In this note, we investigate the convergence behaviour of linear multistep discretizations for singularly perturbed systems, emphasising the features of variable stepsizes. We derive a convergence result for A()-stable linear multistep methods and specify a refined error estimate for backward differentiation formulas. Important ingredients in our convergence analysis are stability bounds for non-autonomous linear problems that are obtained by perturbation techniques. 相似文献
39.
PENG Zhaohui ZHOU Jixun & ZHANG Renhe .Institute of Acoustics Chinese Academy of Sciences Beijing China .School of Mechanical Engineering Georgia Institute of Technology Atlanta GA USA 《中国科学G辑(英文版)》2004,47(6):702-716
1 Introduction Backward scattering of sound due to sediment is the main source of shallow waterreverberation. In order to predict the reverberation or detect sediment properties frommeasured reverberation data, a reasonable in-plane bistatic backward scattering (BBS)model is essential. The scattering can be caused by the roughness of water-sediment in-terface or by inhomogeneities within the volume of sediment. A great deal of researchhas been done on sediment backscattering, most of which h… 相似文献
40.
In this paper we show that the Cahn–Hilliard stochastic PDE has a function valued solution in dimension 4 and 5 when the perturbation is driven by a space-correlated Gaussian noise. We study the regularity of the trajectories of the solution and the absolute continuity of its law at some given time and position. This is done by showing a priori estimates which heavily depend on the specific equation, and by proving general results on stochastic and deterministic integrals involving general operators on smooth domains of d which are parabolic in the sense of Petrovskii, and do not necessarily define a semi-group of operators. These last estimates might be used in a more general framework. 相似文献