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An Analysis of the Key Elements and Barriers of English Listening
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作者 刘云红 《Sino-US English Teaching》 2006年第4期16-18,共3页
While illustrating the process and the essence of listening and analyzing various subjective and objective barriers in listening, the author tries to show that English learners can improve their quality of listening c... While illustrating the process and the essence of listening and analyzing various subjective and objective barriers in listening, the author tries to show that English learners can improve their quality of listening comprehension by transferring the negative elements to the positive ones. 展开更多
关键词 LISTENING positive elements negative elements barriers in listening
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Some Inequalities about the Positive Elements in C~*-Algebra
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作者 汪远征 黄学维 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期29-31,共3页
In this paper, we discussed some improtant inequalities, such as young inequality, Holder inequality and Minkowski inequality,about the positive elements in C~*-Algebra.
关键词 C~*-Algebra positive element
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A POD REDUCED-ORDER SPDMFE EXTRAPOLATING ALGORITHM FOR HYPERBOLIC EQUATIONS 被引量:2
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作者 罗振东 李宏 《Acta Mathematica Scientia》 SCIE CSCD 2014年第3期872-890,共19页
In this article, a proper orthogonal decomposition (POD) method is used to study a classical splitting positive definite mixed finite element (SPDMFE) formulation for second- order hyperbolic equations. A POD redu... In this article, a proper orthogonal decomposition (POD) method is used to study a classical splitting positive definite mixed finite element (SPDMFE) formulation for second- order hyperbolic equations. A POD reduced-order SPDMFE extrapolating algorithm with lower dimensions and sufficiently high accuracy is established for second-order hyperbolic equations. The error estimates between the classical SPDMFE solutions and the reduced-order SPDMFE solutions obtained from the POD reduced-order SPDMFE extrapolating algorithm are provided. The implementation for solving the POD reduced-order SPDMFE extrapolating algorithm is given. Some numerical experiments are presented illustrating that the results of numerical computation are consistent with theoretical conclusions, thus validating that the POD reduced-order SPDMFE extrapolating algorithm is feasible and efficient for solving second-order hyperbolic equations. 展开更多
关键词 Proper orthogonal decomposition splitting positive definite mixed finite element formulation hyperbolic equations error estimate
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Generalized Domination in Ordered Banach Algebras
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作者 Kelvin Muzundu 《Journal of Mathematics and System Science》 2013年第7期335-341,共7页
The following problem in an OBA (ordered Banach algebra) has been studied by various authors: If a and b are positiveelements in an OBA such that 0 ≤ α ≤ b and ifb has a certain property, under what conditions d... The following problem in an OBA (ordered Banach algebra) has been studied by various authors: If a and b are positiveelements in an OBA such that 0 ≤ α ≤ b and ifb has a certain property, under what conditions does a inherit that property? This will be referred to as the domination problem. In this paper we will introduce absolute value |.| in an OBA and obtain results for the domination problem under the more general inequality |α| ≤|b|. We will show that these results are applicable to positive operators on a Banach lattice. Furthermore, it will be demonstrated that some known results for the domination problem in OBAs continue to hold true if 0 ≤ α≤ b is replaced by |a|≤|b|. 展开更多
关键词 Ordered Banach algebra positive element SPECTRUM
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Superconvergence Analysis of Splitting Positive Definite Nonconforming Mixed Finite Element Method for Pseudo-hyperbolic Equations 被引量:7
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作者 Dong-yang SHI Qi-li TANG 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2013年第4期843-854,共12页
In this paper, a new splitting positive definite nonconforming mixed finite element method is proposed for pseudo-hyperbolic equations, in which a quasi-Wilson quadrilateral element is used for the flux p, and the bil... In this paper, a new splitting positive definite nonconforming mixed finite element method is proposed for pseudo-hyperbolic equations, in which a quasi-Wilson quadrilateral element is used for the flux p, and the bilinear element is used for u. Superconvergence results in ||·||div,h norm for p and optimal error estimates in L2 norm for u are derived for both semi-discrete and fully discrete schemes under almost uniform meshes. 展开更多
关键词 pseudo-hyperbolic equations splitting positive definite nonconforming mixed finite element method superclose SUPERCONVERGENCE
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Evaluation of E-sail parameters on central spacecraft attitude stability using a high-fidelity rigid–flexible coupling model
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作者 Chonggang Du Zheng H.Zhu +2 位作者 Changqing Wang Aijun Li Tuanjie Li 《Astrodynamics》 EI CSCD 2024年第2期271-284,共14页
This study examines the impact of electric solar wind sail(E-sail)parameters on the attitude stability of E-sail’s central spacecraft by using a comprehensive rigid–flexible coupling dynamic model.In this model,the ... This study examines the impact of electric solar wind sail(E-sail)parameters on the attitude stability of E-sail’s central spacecraft by using a comprehensive rigid–flexible coupling dynamic model.In this model,the nodal position finite element method is used to model the elastic deformation of the tethers through interconnected two-node tensile elements.The attitude dynamics of the central spacecraft is described using a natural coordinate formulation.The rigid–flexible coupling between the central spacecraft and its flexible tethers is established using Lagrange multipliers.Our research reveals the significant influences of parameters such as tether numbers,tether’s electric potential,and solar wind velocity on attitude stability.Specifically,solar wind fluctuations and the distribution of electric potential on the main tethers considerably affect the attitude stability of the spacecraft.For consistent management,the angular velocities of the spacecraft must remain at target values.Moreover,the attitude stability of a spacecraft has a pronounced dependence on the geometrical configuration of the E-sail,with axisymmetric E-sails proving to be more stable. 展开更多
关键词 electric solar wind sail(E-sail) space tether nodal position finite element method(NPFEM) natural coordinate formulation (NCF) attitude stability
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