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非结构四边形网格下的一类保对称有限体元格式 被引量:5
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作者 聂存云 舒适 盛志强 《计算物理》 EI CSCD 北大核心 2009年第2期175-183,共9页
针对定常扩散问题,在非结构四边形网格下,通过选取特殊的控制体和有限体元空间,建立两种保对称有限体元格式,在拟一致网格剖分下,当扩散系数光滑时,证明有限体元解函数在L2和H1范数下均具有饱和误差阶.数值实验验证理论结果的正确性,同... 针对定常扩散问题,在非结构四边形网格下,通过选取特殊的控制体和有限体元空间,建立两种保对称有限体元格式,在拟一致网格剖分下,当扩散系数光滑时,证明有限体元解函数在L2和H1范数下均具有饱和误差阶.数值实验验证理论结果的正确性,同时表明新格式对扭曲大变形四边形网格、间断系数问题具有较强的适应性.在正交网格下,第二种格式对流(flux)函数在单元中心点的值还具有超逼近性. 展开更多
关键词 非结构四边形网格 保对称有限体元格式 扩散方程 误差估计
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基于空间信息的保对称性共形参数化算法
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作者 王鹏 李海生 《中国科技论文》 CAS 北大核心 2022年第11期1276-1280,1288,共6页
针对传统自由边界平面域共形参数化在模型表面曲面从三维空间共形映射到二维参数域空间时无法保证原有模型对称性的问题,提出了一种基于空间几何信息的保对称性共形参数化(symmetry preserving conformal parameterization,SPCP)算法。... 针对传统自由边界平面域共形参数化在模型表面曲面从三维空间共形映射到二维参数域空间时无法保证原有模型对称性的问题,提出了一种基于空间几何信息的保对称性共形参数化(symmetry preserving conformal parameterization,SPCP)算法。使用基于边界的平面反射对称变换求解输入模型的主对称面,并利用主对称面和边界顶点信息计算对称约束因子,最后通过对称约束因子确定自由边界共形参数化边界固定点,以得到能够保持对称性的共形参数化结果。结果表明,所提方法能够有效保证共形参数化的保对称性特性,并降低共形参数化映射结果的面积畸变和角度畸变,可在飞行器表面结构网格生成中有效提高结构网格生成的对称性和质量。 展开更多
关键词 共形参数化 对称约束因子 空间信息约束 保对称
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微分形式代数上的半对称不保度量联络
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作者 吴彤 《东北师大学报(自然科学版)》 CAS 北大核心 2024年第2期48-52,共5页
引入了Levi-Civita联络的半对称不保度量扰动,即微分形式代数上的半对称不保度量联络.计算了它在微分形式代数上的曲率张量及其Ricci张量.研究了在微分形式代数上的分布,得到了半对称不保度量联络的Gauss-Codazzi-Ricci等式.
关键词 微分形式代数 对称度量联络 Gauss-Codazzi-Ricci等式
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对称保正型h-变换的几个性质
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作者 陈传钟 陈在夫 《电子科技大学学报》 EI CAS CSCD 北大核心 2000年第3期323-325,共3页
通过对称保正型(ε,D(ε))h-变换的暂留性、常返性和不可约性的讨论,证明了对称保正型的暂留性、常返性和不可约性在h-变换下是不变的,由此得到(ε,D(ε))h-结合的m-胎紧m-特殊标准马氏过程的相应性质。
关键词 对称正型 h-变换 暂留性 常返性
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四边形剖分下的对称有限体积元格式
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作者 聂存云 谭敏 李荣军 《江西师范大学学报(自然科学版)》 CAS 北大核心 2005年第6期550-553,共4页
针对一类椭圆问题,在四边形剖分下,构造了一类保对称有限体积元格式,给出了其误差的H1模估计,数值实验验证了理论结果的正确性,其L2模也达到了饱和阶,该格式对非一致网格有好的收敛精度和稳定性.
关键词 四边形剖分 保对称 有限体格元式 误差估计
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谈谈保形变换中分式线性变换的运用
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作者 李清桂 《桂林师范高等专科学校学报》 2001年第4期102-104,共3页
通过公式 ,逆变换 ,保角与伸缩率 ,保交比、保圆周、保对称点等多种途径阐述平面到平面、平面到圆、圆到圆、角形区域到平面 。
关键词 形变换 分式线性变换 交比 保对称 解题技巧 复变函数
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对两点关于圆周对称定义的讨论
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作者 张展云 《大学数学》 1995年第4期172-175,共4页
本文给出了两点关于圆周对称的一种新定义,克服了[1],[2]所给定义的不严密性。
关键词 分式线性变换 保对称点性
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辐射热传导问题的SFVE格式与数值仿真
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作者 聂存云 舒适 +1 位作者 杭旭登 成娟 《系统仿真学报》 CAS CSCD 北大核心 2012年第2期275-283,共9页
在柱坐标系下,首先为多介质的输运管单温辐射热传导和多介质的三温辐射热传导两类模型问题,构造了一种针对非混合网格的保对称有限体元(SFVE-I)格式;接着针对一种特殊混合网格,分别为定常扩散和三温辐射热传导模型问题,构造了一种有限体... 在柱坐标系下,首先为多介质的输运管单温辐射热传导和多介质的三温辐射热传导两类模型问题,构造了一种针对非混合网格的保对称有限体元(SFVE-I)格式;接着针对一种特殊混合网格,分别为定常扩散和三温辐射热传导模型问题,构造了一种有限体元(FVE-II)格式;进行了数值实验与数值仿真,其结果表明:对定常问题,在一致网格上有限体元解函数关于真解函数和流函数的逼近分别具有二阶、一阶精度;对上述两种模型问题,数值仿真得到与实际物理现象基本相符的热传导过程和温度分布,且能量守恒误差均小于5%。 展开更多
关键词 柱坐标 辐射热传导 保对称有限体元格式 混合网格 数值仿真
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K-分式线性变换
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作者 张建元 张昕 《江西师范大学学报(自然科学版)》 CAS 北大核心 2014年第1期42-46,共5页
在K-导数、K-解析(函数)变换、K-共形映射的基础上,研究了K-分式线性变换及其K保圆性、K保对称性、K保交比性等,所得结论是(共轭)解析函数的(共轭)分式线性变换在K-解析函数中的继续和应用.
关键词 K-导数 K-解析函数(变换) K-共形映射 K-分式线性变换 K K保对称 K交比
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完整约束力学系统保Lie对称性差分格式 被引量:13
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作者 张宏彬 吕洪升 顾书龙 《物理学报》 SCIE EI CAS CSCD 北大核心 2010年第8期5213-5218,共6页
提出一种保完整约束力学系统Lie点对称性的差分格式.其具体做法是:首先求出完整约束力学系统的Lie点对称群,并将其延拓到离散的差分格点上;其次利用其特征方程找出独立的离散不变量;再应用独立的离散不变量来构造不变量的差分格式,且此... 提出一种保完整约束力学系统Lie点对称性的差分格式.其具体做法是:首先求出完整约束力学系统的Lie点对称群,并将其延拓到离散的差分格点上;其次利用其特征方程找出独立的离散不变量;再应用独立的离散不变量来构造不变量的差分格式,且此差分格式在连续极限下应给出原系统的微分方程;最后给出一个例子,作为本文结果的说明. 展开更多
关键词 完整约束力学系统 Lie点对称 差分格式
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SAMR网格下求解二维三温辐射扩散问题的自适应PCTL预条件子
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作者 岳孝强 李敏 +1 位作者 周志阳 舒适 《湘潭大学学报(自然科学版)》 CAS 2020年第6期1-7,共7页
本文为结构化自适应网格加密(SAMR)网格下二维三温辐射扩散问题的混合保对称有限体元格式设计了一种新的自适应PCTL预条件子,采用新的两层网格法求解子系统.与基于Ruge-Stüben型代数多重网格法的PGMRES法相比,基于新预条件子的PGM... 本文为结构化自适应网格加密(SAMR)网格下二维三温辐射扩散问题的混合保对称有限体元格式设计了一种新的自适应PCTL预条件子,采用新的两层网格法求解子系统.与基于Ruge-Stüben型代数多重网格法的PGMRES法相比,基于新预条件子的PGMRES法更易于在JASMIN并行框架中实现,且对耦合关系强的情形,其稳健性更好且计算效率更高. 展开更多
关键词 二维三温辐射扩散问题 保对称有限体元 SAMR网格 代数多重网格 自适应PCTL
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Symmetries and Mei Conserved Quantities of Nonholonomic Controllable Mechanical Systems 被引量:5
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作者 XIA Li-Li LI Yuan-Cheng WANG Jing HOU Qi-Bao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3X期415-418,共4页
This paper concentrates on studying the symmetries and a new type of conserved quantities called Mei conserved quantity. The criterions of the Mei symmetry, the Noether symmetry and the Lie symmetry are given. The con... This paper concentrates on studying the symmetries and a new type of conserved quantities called Mei conserved quantity. The criterions of the Mei symmetry, the Noether symmetry and the Lie symmetry are given. The conditions and the forms of the Mei conserved quantities deduced from these three symmetries are obtained. An example is given to illustrate the application of the result. 展开更多
关键词 control nonholonomic mechanical system Mei symmetry Noether symmetry Lie symmetry conserved quantity
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Mei Symmetry and Conserved Ouantity of Tzénoff Equations for Nonholonomic Systems of Non-Chetaev's Type 被引量:18
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作者 ZHENG Shi-Wang XIE Jia-Fang LI Yan-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第4期851-854,共4页
Mei symmetry of Tzenoff equations for nonholonomic systems of non-Chetaev's type under the infinitesimal transformations of groups is studied. Its definitions and discriminant equations of Mei symmetry are given. Suf... Mei symmetry of Tzenoff equations for nonholonomic systems of non-Chetaev's type under the infinitesimal transformations of groups is studied. Its definitions and discriminant equations of Mei symmetry are given. Sufficient and necessary condition of Lie symmetry deduced by the Mei symmetry is also given. Hojman conserved quantity of Tzenoff equations for the systems through Lie symmetry in the condition of special Mei symmetry is obtained. 展开更多
关键词 nonholonomic system Tzenoff equations Mei symmetry conserved quantity
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Unified Symmetry of Hamilton Systems 被引量:3
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作者 XU Xue-Jun QIN Mao-Chang MEI Feng-Xiang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第5X期769-772,共4页
The definition and the criterion of a unified symmetry for a Hamilton system are presented. The sufficient condition under which the Noether symmetry is a unified symmetry for the system is given. A new conserved quan... The definition and the criterion of a unified symmetry for a Hamilton system are presented. The sufficient condition under which the Noether symmetry is a unified symmetry for the system is given. A new conserved quantity,as well as the Noether conserved quantity and the Hojman conserved quantity, deduced from the unified symmetry, is obtained. An example is finally given to illustrate the application of the results. 展开更多
关键词 Hamilton system unified symmetry conserved quantity
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Mei Symmetry of General Discrete Holonomic System 被引量:2
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作者 SHI Shen-Yang CHEN Li-Qun FU Jing-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期607-610,共4页
The Mei symmetry and conserved quantity of general discrete holonomic system are investigated in thispaper.The requirement for an invariant formalism of discrete motion equations is defined to be Mei symmetry.Thecrite... The Mei symmetry and conserved quantity of general discrete holonomic system are investigated in thispaper.The requirement for an invariant formalism of discrete motion equations is defined to be Mei symmetry.Thecriterion when a conserved quantity may be obtained from Mei symmetry is also deduced.An example is discussed forapplications of the results. 展开更多
关键词 discrete mechanics Mei symmetry discrete conserved quantity
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Noether-Mei Symmetry of Mechanical System in Phase Space 被引量:4
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作者 FANG Jian-Hui WANG Peng DING Ning 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期882-884,共3页
In this paper, a new kind of symmetry and its conserved quantities of a mechanical system in phase space are studied. The definition of this new symmetry, i,e., a Noether-Mei symmetry, is presented, and the criterion ... In this paper, a new kind of symmetry and its conserved quantities of a mechanical system in phase space are studied. The definition of this new symmetry, i,e., a Noether-Mei symmetry, is presented, and the criterion of this symmetry is also given. The Noether conserved quantity and the Mei conserved quantity deduced from the Noether-Mei symmetry of the system are obtained. Finally, two examples are given to illustrate the Bpplication of the results. 展开更多
关键词 Noether-Mei symmetry conserved quantity mechanical system phase space
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A New Type of Conserved Quantity of Mei Symmetry for Lagrange Systems 被引量:1
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作者 DING Ning FANG Jian-Hui WANG Peng ZHANG Xiao-Ni 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5X期799-800,共2页
A new type of conserved quantity, which is induced from the Mei symmetry of Lagrange systems, is studied. The conditions for that the new type of conserved quantity exists and the form of the new type of conserved qua... A new type of conserved quantity, which is induced from the Mei symmetry of Lagrange systems, is studied. The conditions for that the new type of conserved quantity exists and the form of the new type of conserved quantity are obtained. An illustrated example is given. The Noether conserved quantity induced from the Mei symmetry of Lagrange systems is a special case of the new type of conserved quantity given in this paper. 展开更多
关键词 Mei symmetry new type of conserved quantity Lagrange system
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Unified Symmetry of Nonholonomic Mechanical Systems with Non-Chetaev's Type Constraints 被引量:3
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作者 XIA Li-Li LI Yuan-Cheng HOU Qi-Bao WANG Jing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第4X期683-686,共4页
Based on the total time derivative along the trajectory of the system, the unified symmetry of nonholonomic mechanical system with non-Chetaev's type constraints is studied. The definition and criterion of the unifie... Based on the total time derivative along the trajectory of the system, the unified symmetry of nonholonomic mechanical system with non-Chetaev's type constraints is studied. The definition and criterion of the unified symmetry of nonholonomic mechanical systems with non-Ohetaev's type constraints are given. A new conserved quantity, as well as the Noether conserved quantity and the Hojman conserved quantity, deduced from the unified symmetry, is obtained. Two examples are given to illustrate the application of the results. 展开更多
关键词 nonholonomic mechanical system of non-Chetaev's type unified symmetry conserved quantity
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New Conserved Quantities of Noether-Mei Symmetry for Nonholonomic Mechanical System 被引量:1
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作者 LIU Yang-Kui FANG Jian-Hui +1 位作者 PANG Ting LIN Peng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期603-606,共4页
Two new types of conserved quantities deduced by Noether-Mei symmetry of nonholonomic mechanicalsystem are studied.The definition and criterion of Noether-Mei symmetry for the system are given.A coordinationfunction i... Two new types of conserved quantities deduced by Noether-Mei symmetry of nonholonomic mechanicalsystem are studied.The definition and criterion of Noether-Mei symmetry for the system are given.A coordinationfunction is introduced,and the conditions under which the Noether-Mei symmetry leads to the two types of conservedquantities and the forms of the two types of conserved quantities are obtained.An illustrative example is given.Thecoordination function can be selected according to the demand for finding the gauge function,and the choice of thecoordination function has multiformity,so more conserved quantities deduced from Noether-Mei symmetry of mechanicalsystem can be obtained. 展开更多
关键词 nonholonomic mechanical system Noether-Mei symmetry new conserved quantity
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Lie Symmetry and Conserved Quantities for Nonholonomic Vacco Dynamical Systems 被引量:3
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作者 DING Ning FANG Jian-Hui 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2X期265-268,共4页
In this paper the Lie symmetry and conserved quantities for nonholonomic Vacco dynamical systems are studied. The determining equation of the Lie symmetry for the system is given. The general Hojman conserved quantity... In this paper the Lie symmetry and conserved quantities for nonholonomic Vacco dynamical systems are studied. The determining equation of the Lie symmetry for the system is given. The general Hojman conserved quantity and the Lutzky conserved quantity deduced from the symmetry are obtained. 展开更多
关键词 Vacco dynamical system Lie symmetry general Hojman conserved quantity Lutzky conserved quantity
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