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微分方程(组)对称向量的吴-微分特征列算法及其应用 被引量:23
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作者 朝鲁 《数学物理学报(A辑)》 CSCD 北大核心 1999年第3期326-332,共7页
给出(偏)微分方程(组)(PDEs)对称向量的吴-微分特征列集(消元)算法理论.把古典和非古典PDEs对称问量的计算问题统-在吴-微分特征列理论框架之下处理.给出了产生PDEs对称向量的无穷小方程和验证已知向量为PDES对称向量的机械... 给出(偏)微分方程(组)(PDEs)对称向量的吴-微分特征列集(消元)算法理论.把古典和非古典PDEs对称问量的计算问题统-在吴-微分特征列理论框架之下处理.给出了产生PDEs对称向量的无穷小方程和验证已知向量为PDES对称向量的机械化原理,理论上彻底克服了传统算法中的缺陷并为计算PDEs对称向量提供了一种新算法.用计算机代数系统mathematica编制了相应的软件包,具体实现了该算法.作为应用给出了Burgers方程的非古典对称向量的完整解答. 展开更多
关键词 吴方法 对称向量 微分方程组 微分特征列集算法
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Mei Symmetry and New Conserved Quantity of Tzenoff Equations for Holonomic Systems 被引量:13
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作者 郑世旺 解加芳 张庆华 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第8期2164-2166,共3页
A new conserved quantity is deduced from Mei symmetry of Tzenoff equations for holonomic systems. The expression of this new conserved quantity is given, and the determining equation to induce this new conserved quant... A new conserved quantity is deduced from Mei symmetry of Tzenoff equations for holonomic systems. The expression of this new conserved quantity is given, and the determining equation to induce this new conserved quantity is presented. The results exhibit that this new method is easier to find more conserved quantities than the previously reported ones. Finally, application of this new result is presented by a practical example. 展开更多
关键词 LIE symmetries FORM INVARIANCE NONHOLONOMIC SYSTEMS HAMILTONIAN SYSTEM
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(2+1)维Boussinesq方程的对称、约化、群不变解及守恒律 被引量:14
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作者 董仲周 王玲 《聊城大学学报(自然科学版)》 2007年第1期21-24,共4页
通过利用李群方法,得到了(2+1)维Boussinesq方程的对称、约化及群不变解,推广了文献[3]的关于此方程精确解的结果.由于对称和守恒律之间有密切的关系,同时找到了此方程的无穷多守恒律.
关键词 李群方法 (2+1)维BOUSSINESQ方程 对称 群不变解 守恒律
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Rectangle expansion A* pathfinding for grid maps 被引量:10
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作者 Zhang An Li Chong Bi Wenhao 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第5期1385-1396,共12页
Search speed, quality of resulting paths and the cost of pre-processing are the principle evaluation metrics of a pathfinding algorithm. In this paper, a new algorithm for grid-based maps, rectangle expansion A* (RE... Search speed, quality of resulting paths and the cost of pre-processing are the principle evaluation metrics of a pathfinding algorithm. In this paper, a new algorithm for grid-based maps, rectangle expansion A* (REA*), is presented that improves the performance of A* significantly. REA* explores maps in units of unblocked rectangles. All unnecessary points inside the rectangles are pruned and boundaries of the rectangles (instead of individual points within those boundaries) are used as search nodes. This makes the algorithm plot fewer points and have a much shorter open list than A*. REA* returns jump and grid-optimal path points, but since the line of sight between jump points is protected by the unblocked rectangles, the resulting path of REA" is usually better than grid-optimal. The algorithm is entirely online and requires no offline pre-processing. Experimental results for typical benchmark problem sets show that REA* can speed up a highly optimized A* by an order of magnitude and more while preserving completeness and optimality. This new algorithm is competitive with other highly successful variants of A*. 展开更多
关键词 Breaking path symmetries Grid Heuristic algorithms Path search Variant of A*
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试论“上”与“下”的对称与不对称现象 被引量:1
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作者 范洁清 《平顶山师专学报》 2003年第6期57-62,共6页
对称与不对称现象是存在于语言世界的普遍规律,理应为语言学界所关注并进行科学、系统的研究。从理论上说"上"与"下"应为一一对应的关系,有"上"即有"下"。但语言在受语言内部调节系统制约的同... 对称与不对称现象是存在于语言世界的普遍规律,理应为语言学界所关注并进行科学、系统的研究。从理论上说"上"与"下"应为一一对应的关系,有"上"即有"下"。但语言在受语言内部调节系统制约的同时,也受到语言外社会文化和心理因素的影响。"上"的构词能力远大于"下"。"上"和"下"构成的词和短语在发展演变过程中其语义也在发生变化。这些都是导致对称破缺的因素。主要以"上""下"构成的各类词和词组为例,用归纳法描写、分析其对称与不对称性。旨在以显性对称与不对称的实例为依据,找出它们发展演变的规律,科学地预测其演变方向,研究开发潜性对称与不对称的空间。 展开更多
关键词 对称 不对称 “上” “下” 显性 潜性
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基于El-Nabulsi分数阶模型的广义Birkhoff系统Noether对称性研究 被引量:9
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作者 张毅 丁金凤 《南京理工大学学报》 EI CAS CSCD 北大核心 2014年第3期409-413,共5页
为了进一步揭示力学系统的对称性与守恒量之间的内在关系,基于El-Nabulsi分数阶模型提出并研究了广义Birkhoff系统的Noether定理。首先,提出分数阶广义El-Nabulsi-PfaffBirkhoff原理,建立广义El-Nabulsi-Birkhoff方程。其次,基于El-Nabu... 为了进一步揭示力学系统的对称性与守恒量之间的内在关系,基于El-Nabulsi分数阶模型提出并研究了广义Birkhoff系统的Noether定理。首先,提出分数阶广义El-Nabulsi-PfaffBirkhoff原理,建立广义El-Nabulsi-Birkhoff方程。其次,基于El-Nabulsi-Pfaff作用量在无限小变换下的不变性,给出广义Birkhoff系统Noether对称性的定义和判据。最后,提出广义Birkhoff系统的Noether定理。该文研究结果可进一步应用于完整和非完整约束系统。 展开更多
关键词 力学系统 对称性 守恒量 El-Nabulsi分数阶模型 广义BIRKHOFF系统 NOETHER定理 无限小变换 完整约束系统 非完整约束系统
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(2+1)维Gardner方程的对称、约化及其群不变解 被引量:9
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作者 许斌 刘希强 《量子电子学报》 CAS CSCD 北大核心 2009年第5期531-536,共6页
利用经典李群方法,得到了一类(2+1)维Gardner方程的显式解,推广了唐和陈的某些结果,并且得到了该方程的对称、约化及其群不变解。
关键词 非线性方程 李群方法 Gardner方程 对称 群不变解
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Study of (2+1)-Dimensional Higher-Order Broer-Kaup System 被引量:8
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作者 WANG Ling LIU Xi-Qiang DONG Zhong-Zhou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期403-408,共6页
Painleve property and infinite symmetries of the (2+1)-dimensional higher-order Broer-Kaup (HBK) system are studied in this paper. Using the modified direct method, we derive the theorem of general symmetry gro.u... Painleve property and infinite symmetries of the (2+1)-dimensional higher-order Broer-Kaup (HBK) system are studied in this paper. Using the modified direct method, we derive the theorem of general symmetry gro.ups to (2+1)-dimensional HBK system. Based on our theorem, some new forms of solutions are obtained. We also find infinite number of conservation laws of the (2+1)-dimensional HBK system. 展开更多
关键词 (2+1)-dimensional HBK system Painleve property symmetries exact solution conservation laws
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Approximate Generalized Conditional Symmetries for the Perturbed Nonlinear Diffusion-Convection Equations 被引量:4
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作者 张顺利 屈长征 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第3期527-530,共4页
The concept of approximate generalized conditional symmetry (A GCS) as a generalization to both approximate Lie point symmetry and generalized conditional symmetry is introduced, and it is applied to study the pertu... The concept of approximate generalized conditional symmetry (A GCS) as a generalization to both approximate Lie point symmetry and generalized conditional symmetry is introduced, and it is applied to study the perturbed nonlinear diffusion-convection equations. Complete classification of those perturbed equations which admit cerrain types of AGCSs is derived. Some approximate solutions to the resulting equations can be obtained via the AGCS and the corresponding unperturbed equations. 展开更多
关键词 PARTIAL-DIFFERENTIAL-EQUATIONS FUNCTIONAL VARIABLE SEPARATION INITIAL-VALUE PROBLEMS POTENTIAL symmetries WAVE-EQUATION REDUCTION CLASSIFICATION
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Fabrication of Two-Dimensional Photonic Crystals with Triangular Rods by Single-Exposure Holographic Lithography 被引量:5
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作者 濮怡莹 梁冠全 +1 位作者 毛卫东 董建文 《Chinese Physics Letters》 SCIE CAS CSCD 2007年第4期983-985,共3页
We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular 'atoms' arranged in a triangular lattice. Simulation results show that double absolute pho... We demonstrate a single-exposure holographic fabrication of two-dimensional photonic crystal with round- cornered triangular 'atoms' arranged in a triangular lattice. Simulation results show that double absolute photonic band gaps exist in this structure. Our experimental results show that holographic lithography can be used to fabricate photonic crystals not only with various lattice structures but also with various kinds of structures of the atoms, to obtain absolute band gaps or a particular band gap structure. Furthermore, the single-exposure holographic method not only makes the fabrication process simple and convenient but also makes the structures of the atoms more perfect. 展开更多
关键词 VISIBLE SPECTRUM symmetries LATTICE PHASE
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CTE Solvability, Nonlocal Symmetries and Exact Solutions of Dispersive Water Wave System 被引量:7
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作者 陈春丽 楼森岳 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第5期545-550,共6页
A consistent tanh expansion (CTE) method is developed for the dispersion water wave (DWW) system. For the CTE solvable DlVVC system, there are two branches related to tanh expansion, the main branch is consistent ... A consistent tanh expansion (CTE) method is developed for the dispersion water wave (DWW) system. For the CTE solvable DlVVC system, there are two branches related to tanh expansion, the main branch is consistent while the auxiliary branch is not consistent. From the consistent branch, we can obtain infinitely many exact significant solutions including the soliton-resonant solutions and soliton-periodic wave interactions. From the inconsistent branch, only one special solution can be found. The CTE related nonlocal symmetries are also proposed. The nonlocai symmetries can be localized to find finite Backlund transformations by prolonging the model to an enlarged one. 展开更多
关键词 consistent tanh expansion dispersion water wave (DWW) system nonlocal symmetries the con-sistent Riccati expansion
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2+1维耗散长水波方程组的对称及精确解 被引量:7
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作者 高洁 张建奎 郭美玉 《聊城大学学报(自然科学版)》 2007年第3期23-27,92,共6页
应用李群对称方法,求解(2+1)维耗散长水波方程组,得到了该方程组的对称、相似约化和精确解.
关键词 对称 耗散长水波方程 相似约化 精确解
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Thermal photonics with broken symmetries 被引量:6
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作者 Tianji Liu Cheng Guo +1 位作者 Wei Li Shanhui Fan 《eLight》 2022年第1期317-336,共20页
Nanophotonic engineering provides an effective platform to manipulate thermal emission on-demand,enabling unprecedented heat management superior to conventional bulk materials.Amongst a plethora of nanophotonic struct... Nanophotonic engineering provides an effective platform to manipulate thermal emission on-demand,enabling unprecedented heat management superior to conventional bulk materials.Amongst a plethora of nanophotonic structures,symmetries play an important role in controlling radiative heat transfer in both near-field and far-field.In physics,broken symmetries generally increase the degree of freedom in a system,enriching the understanding of physical mechanisms and bringing many exciting opportunities for novel applications.In this review,we discussed the underlying physics and functionalities of nanophotonic structures with broken geometrical symmetries,engineered mode symmetries,and broken reciprocity for the control of thermal emission.We overview a variety of physical phenomena and interesting applications,and provide the outlook for future development. 展开更多
关键词 MATERIALS FIELD symmetries
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(2+1)维Boiti-Leon-Manna-Pempinelli方程的对称、精确解及守恒律 被引量:7
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作者 刘娜 刘希强 《量子电子学报》 CAS CSCD 北大核心 2008年第5期546-552,共7页
利用李群分析方法,得到了(2+1)维Boiti-Leon-Manna-Pempinelli(BLMP)方程的对称、相似约化和新的精确解,包括有理函数解、双曲函数解、雅克比椭圆函数解和三角周期解。同时找到了此方程的无穷多守恒律。
关键词 非线性方程 (2+1).维BLMP方程 李群分析方法 对称 精确解 守恒律
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耦合KdV方程组的对称及精确解 被引量:7
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作者 郭美玉 高洁 《聊城大学学报(自然科学版)》 2008年第4期28-31,共4页
应用李群对称方法讨论了耦合KdV方程组,得到了该方程组的对称、相似约化和精确解.
关键词 对称 相似约化 精确解 耦合KDV方程
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Symmetries and bilinear equations for the modified BKP hierarchy
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作者 Weici Guo Wenchuang Guan +1 位作者 Shen Wang Jipeng Cheng 《Science China Mathematics》 SCIE CSCD 2023年第7期1529-1544,共16页
The modified Kadomtsev-Petviashvili hierarchy of B type(mBKP hierarchy)and its constrained cases are investigated from the aspect of the Lax formulation.Starting from the Lax equation of the mBKP hierarchy,we firstly ... The modified Kadomtsev-Petviashvili hierarchy of B type(mBKP hierarchy)and its constrained cases are investigated from the aspect of the Lax formulation.Starting from the Lax equation of the mBKP hierarchy,we firstly derive the bilinear equations and show the existence of the tau functions.Then the additional symmetries are constructed,and the corresponding generator is showed to be the squared eigenfunction symmetry.After that,the actions of the additional symmetries on the tau functions are given.At last,the Lax formulation of the constrained mBKP hierarchy is investigated and the corresponding bilinear equations are also discussed. 展开更多
关键词 mBKP hierarchy tau functions additional symmetries squared eigenfunction symmetries constrained mBKP hierarchy bilinear equations
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Matter-Antimatter Asymmetry from Preon Condensation Prior to the Hadron Epoch
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作者 Richard B. Holmes 《Journal of Modern Physics》 2023年第11期1437-1451,共15页
A universe consisting of protons, neutrons, and electrons with electrical neutrality is consistent with an equal number of c and preons, assuming the rishon preon theory of Shupe and Harari. Similarly, a universe cons... A universe consisting of protons, neutrons, and electrons with electrical neutrality is consistent with an equal number of c and preons, assuming the rishon preon theory of Shupe and Harari. Similarly, a universe consisting of antiprotons, antineutrons, and positrons with electrical neutrality is consistent with an equal number of c and preons. Hence, any combination of such matter-antimatter compositions is also consistent with an equal number of c and preons and overall electrical neutrality. It is proposed that the difference observed in baryon-antibaryon number density relative to photon number density, ~5 × 10<sup>-10</sup>, is due to allocation of preons between matter and antimatter during preon condensation into normal matter. Three approaches of increasing rigor and complexity are considered: 1) an allocation at times corresponding to the Planck temperature due to fluctuations, 2) an allocation at times corresponding to quark formation due to preon bonding, and 3) an allocation at times corresponding to the electroweak scale. All approaches can give the correct order of magnitude of the asymmetry assuming out-of-equili-brium freeze-out and a slight and allowed charge (C) asymmetry in preon condensation in a self-consistent quantum field theory. Sakharov’s baryon non-conservation condition is evidently circumvented with these approaches, because they assume another level of matter (preons) which is present before quark formation. Thus, preons can provide an elementary explanation of primordial matter-antimatter asymmetry. A relationship between Higgs boson states and preons is proposed. 展开更多
关键词 Matter-Antimatter Asymmetry COSMOLOGY Astroparticle Physics Quantum Field Theory Global symmetries
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B-L model with D_(4)×Z_(4)×Z_(2)symmetry for fermion mass hierarchies and mixings
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作者 V.V.Vien 《Chinese Physics C》 SCIE CAS CSCD 2024年第6期11-30,共20页
We constructed a gauge B-L model with D_(4)×Z_(4)×Z_(2)symmetry to explain the quark and lepton mass hierarchies and their mixings with realistic CP phases via the type-I seesaw mechanism.Six quark mases,thr... We constructed a gauge B-L model with D_(4)×Z_(4)×Z_(2)symmetry to explain the quark and lepton mass hierarchies and their mixings with realistic CP phases via the type-I seesaw mechanism.Six quark mases,three quark mixing angles,and the CP phase in the quark sector take the central values whereas Yukawa couplings in the quark sector are diluted in a range of difference of three orders of magnitude by the perturbation theory at the first order.Concerning the neutrino sector,a small neutrino mass is achieved by the type-I seesaw mechanism.Both inverted and normal neutrino mass hierarchies are consistent with the experimental data.The predicted sum of neutrino masses for normal and inverted hierarchies,the effective neutrino masses,and the Dirac CP phase are also consistent with recently reported limits. 展开更多
关键词 flavor symmetries quark and lepton masses and mixing extensions of electroweak gauge sector neutrino mass and mixing non-standard-model neutrinos right-handed neutrinos D4 discrete symmetry
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Applications of cnoidal and snoidal wave solutions via optimal system of subalgebras for a generalized extended (2+1)-D quantum Zakharov-Kuznetsov equation with power-law nonlinearity in oceanography and ocean engineering
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作者 Oke Davies Adeyemo 《Journal of Ocean Engineering and Science》 SCIE 2024年第2期126-153,共28页
The nonlinear evolution equations have a wide range of applications,more precisely in physics,biology,chemistry and engineering fields.This domain serves as a point of interest to a large extent in the world’s mathem... The nonlinear evolution equations have a wide range of applications,more precisely in physics,biology,chemistry and engineering fields.This domain serves as a point of interest to a large extent in the world’s mathematical community.Thus,this paper purveys an analytical study of a generalized extended(2+1)-dimensional quantum Zakharov-Kuznetsov equation with power-law nonlinearity in oceanography and ocean engineering.The Lie group theory of differential equations is utilized to compute an optimal system of one dimension for the Lie algebra of the model.We further reduce the equation using the subalgebras obtained.Besides,more general solutions of the underlying equation are secured for some special cases of n with the use of extended Jacobi function expansion technique.Consequently,we secure new bounded and unbounded solutions of interest for the equation in various solitonic structures including bright,dark,periodic(cnoidal and snoidal),compact-type as well as singular solitons.The applications of cnoidal and snoidal waves of the model in oceanography and ocean engineering for the first time,are outlined with suitable diagrams.This can be of interest to oceanographers and ocean engineers for future analysis.Furthermore,to visualize the dynamics of the results found,we present the graphic display of each of the solutions.Conclusively,we construct conservation laws of the understudy equation via the application of Noether’s theorem. 展开更多
关键词 A generalized extended(2+1)-dimensional quantum Zakharov-Kuznetsov equation Lie point symmetries Optimal system of subalgebras Cnoidal and snoidal waves Extended Jacobi function expansion technique Conservation laws
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Ren-integrable and ren-symmetric integrable systems
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作者 S Y Lou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第3期62-69,共8页
A new type of symmetry,ren-symmetry,describing anyon physics and corresponding topological physics,is proposed.Ren-symmetry is a generalization of super-symmetry which is widely applied in super-symmetric physics such... A new type of symmetry,ren-symmetry,describing anyon physics and corresponding topological physics,is proposed.Ren-symmetry is a generalization of super-symmetry which is widely applied in super-symmetric physics such as super-symmetric quantum mechanics,super-symmetric gravity,super-symmetric string theory,super-symmetric integrable systems and so on.Supersymmetry and Grassmann numbers are,in some sense,dual conceptions,and it turns out that these conceptions coincide for the ren situation,that is,a similar conception of ren-number(R-number)is devised for ren-symmetry.In particular,some basic results of the R-number and ren-symmetry are exposed which allow one to derive,in principle,some new types of integrable systems including ren-integrable models and ren-symmetric integrable systems.Training examples of ren-integrable KdV-type systems and ren-symmetric KdV equations are explicitly given. 展开更多
关键词 symmetries integrable systems anyon physics extended supersymmetry ren-symmetry
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