全文获取类型
收费全文 | 54篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 3篇 |
力学 | 4篇 |
综合类 | 2篇 |
数学 | 41篇 |
物理学 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有58条查询结果,搜索用时 31 毫秒
41.
We discuss the eigenvalue problem for n-th order equations with multipoint boundary conditions. We present the variational method in spite of the fact that the nonlinearity is dependent on the derivative of n/2 order. The results can be applied applied to both sublinear and superlinear cases. 相似文献
42.
Mixed finite element (MFE) and multipoint flux approximation (MPFA) methods have similar properties and are well suited for the resolution of Darcy's flow on anisotropic and heterogeneous domains. In this work, the link between hybrid and MPFA formulations is shown algebraically for the lowest order mixed methods of Raviart–Thomas (RT0) and Brezzi–Douglas–Marini (BDM1) on triangles. The efficiency of the four mixed formulations (Hybrid_RT0, MPFA_RT0, Hybrid_BDM1 and MPFA_BDM1) is investigated on high anisotropic and heterogeneous media and for unstructured triangular discretizations. Numerical experiments show that the MPFA_BDM1 formulation outperforms both Hybrid_RT0 and Hybrid_BDM1 in the case of anisotropic domains and highly unstructured meshes. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
43.
This paper considers parametric nonlinear control problems subject to mixed control-state constraints. The data perturbations are modeled by a parameterp of a Banach space. Using recent second-order sufficient conditions (SSC), it is shown that the optimal solution and the adjoint multipliers are differentiable functions of the parameter. The proof blends numerical shooting techniques for solving the associated boundary-value problem with theoretical methods for obtaining SSC. In a first step, a differentiable family of extremals for the underlying parameteric boundary-value problem is constructed by assuming the regularity of the shooting matrix. Optimality of this family of extremals can be established in a second step when SSC are imposed. This is achieved by building a bridge between the variational system corresponding to the boundary-value problem, solutions of the associated Riccati ODE, and SSC.Solution differentiability provides a theoretical basis for performing a numerical sensitivity analysis of first order. Two numerical examples are worked out in detail that aim at reducing the considerable deficit of numerical examples in this area of research.This paper is dedicated to Professor J. Stoer on the occasion of his 60th birthday.The authors are indebted to K. Malanowski for helpful discussions. 相似文献
44.
We consider the boundary value problem
where r 2, n
i 1 for i = 1, ... ,r,
and 0 = t
1 < t
2 < ... < t
r = 1. Criteria are offered for the existence of double and triple positive (in some sense) solutions of the boundary value problem. Further investigation on the upper and lower bounds for the norms of these solutions is carried out for special cases. We also include several examples to illustrate the importance of the results obtained. 相似文献
45.
In this survey the notion of a balanced best multipoint local approximation is fully exposed since they were treated in the Lp spaces and recent results in Orlicz spaces.The notion of balanced point,introduced by Chui et al.in 1984 are extensively used. 相似文献
46.
Immobilization/stabilization of lipase fromCandida rugosa 总被引:1,自引:0,他引:1
Christina Otero Antonio Ballesteros Josí M. Guisán 《Applied biochemistry and biotechnology》1988,19(2):163-175
With the aim of fixing the enzyme to the matrix by multiple covalent linkages, lipase from Candida rugosa (formerly cylindracea) has been insolubilized through its amino groups on Sepharose 6B previously activated with 2,3-epoxy-1-propanol. Two main variables that are known to control the number of bonds formed have been tested: the contact time between enzyme and activated support, and the temperature at which the immobilization reaction is carried out. Studies on activity and stability of the different derivatives prepared showed that higher temperatures and longer contact times lead to insolubilized enzymes that are more resistant to inactivation by temperature and the presence of organic solvents. At 50 degrees C and pH 7.2, the insoluble lipase was found to be 140 times more stable than its soluble counterpart. 相似文献
47.
We study the Abel-summability of the eigenfunction expansions associated with the differential operator L generated by and splitting three-point boundary conditions. It is shown that there is no straightforward analogy between multipoint and twopoint boundary value problems. Counterexamples show that our main results are best possible. Classification. 34L10, 34B10. 相似文献
48.
姚庆六 《新疆大学学报(理工版)》2009,26(2):145-149
考察了二阶三点边值问题u”(t)+f(t,u(t))=0,0〈t〈1;αu(O)=βu’(0),ku(η)=u(1)的正解存在性与多解性,其中允许f(t,u)在t=0,t=1处奇异.利用锥上的Krasnosel’skii不动点定理获得了几个局部存在定理. 相似文献
49.
50.
An iterative scheme, in which two-point boundary-value problems (TPBVP) are solved as multipoint boundary-value problems (MPBVP), which are independent TPBVPs in each iteration and on each subdomain, is derived for second-order ordinary differential equations. Several equations are solved for illustration. In particular, the algorithm is described in detail for the first boundary-value problem (FBVP) and second boundary-value problem (SBVP). A possible extension to higher-order BVPs is discussed briefly. The procedure may be used when the original TPBVP cannot be solved (does not converge) in a single long domain. It is suitable for implementation on computers with parallel processing. However, that issue is beyond the scope of this paper. The long domain is cut into a large number of subdomains and, based on assumed boundary conditions at the interface points, the resulting local BVPs are solved by any convenient conventional method. The local solutions are then patched by using simple matching formulas, which are derived below, rather than solving large systems of algebraic equations, as it is done in similar existing methods. Assuming that the local solutions are obtained by the most efficient methods, the overall convergence speed depends on the speed of matching. The proposed matching algorithm is based on a fixed-point iteration and has only a linear convergence rate. The rate can be made quadratic by applying standard accelerating schemes, which is beyond the scope of this article. 相似文献