排序方式: 共有83条查询结果,搜索用时 15 毫秒
41.
Sheikholeslami M. Arabkoohsar A. Babazadeh Houman 《Journal of Thermal Analysis and Calorimetry》2020,140(2):825-834
Journal of Thermal Analysis and Calorimetry - In present article, influence of magnetic forces on migration of nanomaterial through a permeable zone via an innovative method is investigated. The... 相似文献
42.
Mahmood Tajbaksh Maryam Farhang Hamid Reza Mardani Rahman Hosseinzadeh Yaghoub Sarrafi 《催化学报》2013,34(12):2217-2222
A one pot three‐component coupling reaction of phenylacetylene, aldehyde, and amine derivatives in the presence of Cu(II) Salen complex as an efficient heterogeneous catalyst under solvent‐free conditions is reported. The catalyst displayed high activity and afforded the corresponding propargylamines in good to excellent yields. This method provides a wide range of substrate applicability. The catalyst was reused several times without significant loss of its catalytic activity. 相似文献
43.
This paper presents a new approach to interpolate the mechanical fields associated to a given mesh of the computational domain which satisfy the equilibrium equations together with the mechanical criteria which are quadratical in terms of these fields. The method is based on the diffuse approximation techniques. These allow us to construct a field of globally arbitrary order of continuity which approximates accurately the initial discrete mechanical fields. Indeed, the construction is based locally on the resolution of a quadratical optimisation problem under degenerate quadratical constraints for which we propose an analytical solution. The method is applied, in particular, to an equilibrium problem of elastoplastic solid with non linear hardening. To cite this article: P. Villon et al., C. R. Mecanique 330 (2002) 313–318. 相似文献
44.
We propose a methodology to simplify the parameterization of a surface composed of parametric patches, typically encountered in CAD (computer aided design) environments. This new parameterization is defined via the construction of an adaptive triangulation, called support, of each patch. The adaptation is governed by the control of the gap between the initial parameterization of the patch and that of the support. This support is used to generate the mesh of the CAD surface using an indirect approach, in which the mesh is generated via the parametric domains. The support makes it possible to disconnect the mesher from the CAD system, and in this sense it constitutes a universal tool for meshing such surfaces. An application example is given to show the pertinency of our methodology. 相似文献
45.
46.
Shafee Ahmad Bhatti M. M. Muhammad Taseer Kumar Rakesh Nam Nguyen Dang Babazadeh Houman 《Journal of Thermal Analysis and Calorimetry》2021,144(3):1013-1022
Journal of Thermal Analysis and Calorimetry - In the present research, outputs of numerical modeling of hybrid nanomaterial flow structure and thermal behavior were investigated and in-house code... 相似文献
47.
Dalvand Houman Moradi Moghadam Ali Jabari 《Journal of Thermal Analysis and Calorimetry》2019,135(1):657-669
Journal of Thermal Analysis and Calorimetry - The effects of nanofluids (Al2O3–water) on the overall thermal performance of an annular enclosure (or jacket) are experimentally investigated... 相似文献
48.
We consider linear divergence-form scalar elliptic equations and vectorial equations for elasticity with rough (L
∞(Ω),
W ì \mathbb Rd{\Omega \subset \mathbb R^d}) coefficients a(x) that, in particular, model media with non-separated scales and high contrast in material properties. While the homogenization
of PDEs with periodic or ergodic coefficients and well separated scales is now well understood, we consider here the most
general case of arbitrary bounded coefficients. For such problems, we introduce explicit and optimal finite dimensional approximations
of solutions that can be viewed as a theoretical Galerkin method with controlled error estimates, analogous to classical homogenization
approximations. In particular, this approach allows one to analyze a given medium directly without introducing the mathematical
concept of an e{\epsilon} family of media as in classical homogenization. We define the flux norm as the L
2 norm of the potential part of the fluxes of solutions, which is equivalent to the usual H
1-norm. We show that in the flux norm, the error associated with approximating, in a properly defined finite-dimensional space,
the set of solutions of the aforementioned PDEs with rough coefficients is equal to the error associated with approximating
the set of solutions of the same type of PDEs with smooth coefficients in a standard space (for example, piecewise polynomial).
We refer to this property as the transfer property. A simple application of this property is the construction of finite dimensional approximation spaces with errors independent
of the regularity and contrast of the coefficients and with optimal and explicit convergence rates. This transfer property
also provides an alternative to the global harmonic change of coordinates for the homogenization of elliptic operators that
can be extended to elasticity equations. The proofs of these homogenization results are based on a new class of elliptic inequalities.
These inequalities play the same role in our approach as the div-curl lemma in classical homogenization. 相似文献
49.
Variational integrators are symplectic-momentum preserving integrators that are based on a discrete variational formulation of the underlying system. So far, variational integrators have been mainly developed and used for a wide variety of mechanical systems. In this work, we develop a variational integrator for the simulation of electric circuits. An appropriate variational formulation is presented to model the circuit from which the equations of motion are derived. Finally, a corresponding time-discrete variational formulation provides an iteration scheme for the simulation of the electric circuit. In this way, a variational integrator is constructed that gains several advantages. A comparison to standard integration techniques shows that even for simple LCR circuits a better long-time energy behavior and frequency preservation can be obtained. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
50.
用冲击波应力历史曲线确定材料物态方程参数 总被引:2,自引:0,他引:2
提出一种确定材料物态方程参数的新方法,即从一次平面碰撞实验中单个拉格朗日量计记录的应力历史曲线出发,建立非线性优化模型,进而确定材料的物态方程参数。计算结果表明了这种方法的有效性。还考察了权重的选取对于最后优化结果的影响。 相似文献