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Difference Discrete Variational Principles, Euler?Lagrange Cohomology and Symplectic, Multisymplectic Structures III: Application to Symplectic and Multisymplectic Algorithms 被引量:10
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作者 GUOHan-Ying WUKe 等 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第3期257-264,共8页
In the previous papers I and II, we have studied the difference discrete variational principle and the Euler?Lagrange cohomology in the framework of multi-parameter differential approach. We have gotten the difference... In the previous papers I and II, we have studied the difference discrete variational principle and the Euler?Lagrange cohomology in the framework of multi-parameter differential approach. We have gotten the difference discrete Euler?Lagrange equations and canonical ones for the difference discrete versions of classical mechanics and field theory as well as the difference discrete versions for the Euler?Lagrange cohomology and applied them to get the necessary and sufficient condition for the symplectic or multisymplectic geometry preserving properties in both the Lagrangian and Hamiltonian formalisms. In this paper, we apply the difference discrete variational principle and Euler?Lagrange cohomological approach directly to the symplectic and multisymplectic algorithms. We will show that either Hamiltonian schemes or Lagrangian ones in both the symplectic and multisymplectic algorithms are variational integrators and their difference discrete symplectic structure-preserving properties can always be established not only in the solution space but also in the function space if and only if the related closed Euler?Lagrange cohomological conditions are satisfied. 展开更多
关键词 discrete variation Euler-Lagrange cohomology symplectic algorithm multisymplectic algorithm
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Difference Discrete Variational Principles,Euler—Lagrange Cohomology and Symplectic,Multisymplectic Structures I:Difference Discrete Variational Principle 被引量:14
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作者 GUOHan-Ying WUKe 等 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第1期1-10,共10页
In this first paper of a series, we study the difference discrete variational principle in the framework of multi-parameter differential approach by regarding the forward difference as an entire geometric object in vi... In this first paper of a series, we study the difference discrete variational principle in the framework of multi-parameter differential approach by regarding the forward difference as an entire geometric object in view of noncommutative differential geometry. Regarding the difference as an entire geometric object, the difference discrete version of Legendre transformation can be introduced. By virtue of this variational principle, we can discretely deal with the variation problems in both the Lagrangian and Hamiltonian formalisms to get difference discrete Euler-Lagrange equations and canonical ones for the difference discrete versions of the classical mechanics and classical field theory. 展开更多
关键词 变分原理 欧拉拉格郎日上同伦 合成结构
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Symplectic Schemes for Birkhoffian System 被引量:8
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作者 SUHong-Ling QINMeng-Zhao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第3期329-334,共6页
A universal symplectic structure for a Newtonian system including nonconservative cases can be constructed in the framework of Birkhoffian generalization of Hamiltonian mechanics. In this paper the symplectic geometry... A universal symplectic structure for a Newtonian system including nonconservative cases can be constructed in the framework of Birkhoffian generalization of Hamiltonian mechanics. In this paper the symplectic geometry structure of Birkhoffian system is discussed, then the symplecticity of Birkhoffian phase flow is presented. Based on these properties we give a way to construct symplectic schemes for Birkhoffian systems by using the generating function method. 展开更多
关键词 Birkhoffran system symplectic structure generating function method symplectic scheme
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Difference Discrete Variational Principle,Euler—Lagrange Cohomology and Symplectic,Multisymplectic Structures II:Euler—Lagrange Cohomology 被引量:9
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作者 GUOHan-Ying WUKe 等 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第2期129-138,共10页
In this second paper of a series of papers, we explore the difference discrete versions for the Euler?Lagrange cohomology and apply them to the symplectic or multisymplectic geometry and their preserving properties in... In this second paper of a series of papers, we explore the difference discrete versions for the Euler?Lagrange cohomology and apply them to the symplectic or multisymplectic geometry and their preserving properties in both the Lagrangian and Hamiltonian formalisms for discrete mechanics and field theory in the framework of multi-parameter differential approach. In terms of the difference discrete Euler?Lagrange cohomological concepts, we show that the symplectic or multisymplectic geometry and their difference discrete structure-preserving properties can always be established not only in the solution spaces of the discrete Euler?Lagrange or canonical equations derived by the difference discrete variational principle but also in the function space in each case if and only if the relevant closed Euler?Lagrange cohomological conditions are satisfied. 展开更多
关键词 discrete variation Euler-Lagrange cohomology symplectic and multisymplectic structures
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Difference Discrete Variational Principle in Discrete Mechanics and Symplectic Algorithm 被引量:5
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作者 LUOXu-Dong GUOHan-Ying +1 位作者 LIYu-Qi WUKe 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第3X期443-452,共10页
We propose the difference discrete variational principle in discrete mechanics and symplectic algorithmwith variable step-length of time in finite duration based upon a noncommutative differential calculus established... We propose the difference discrete variational principle in discrete mechanics and symplectic algorithmwith variable step-length of time in finite duration based upon a noncommutative differential calculus established inthis paper. This approach keeps both symplecticity and energy conservation discretely. We show that there exists thediscrete version of the Euler-Lagrange cohomology in these discrete systems. We also discuss the solution existencein finite time-length and its site density in continuous limit, and apply our approach to the pendulum with periodicperturbation. The numerical results are satisfactory. 展开更多
关键词 数值计算 耦对映射算法 离散结构 哈密顿结构 微分变量离散原理 勒让德变换 数学物理方法
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Double—Pulse Spectra and Closed—Orbits:Photodetachment of H^— in parallel Electric and Magnetic Fields 被引量:5
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作者 DUMeng-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第6期705-708,共4页
We derive a formula for double-pulse spectra from closed-orbit theory. We then calculate the double-pulse photodetachment spectra of H<SUP>?</SUP> in the presence of parallel electric and magnetic fields. ... We derive a formula for double-pulse spectra from closed-orbit theory. We then calculate the double-pulse photodetachment spectra of H<SUP>?</SUP> in the presence of parallel electric and magnetic fields. We analyze the spectra in terms of closed-orbits of the system. We suggest a method for the measurement of a phase associated with each closed-orbit. 展开更多
关键词 closed-orbit theory PHOTODETACHMENT Stark effect
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On Symplectic and Multisymplectic Structures and Their Discrete Versions in Lagrangian Formalism 被引量:4
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作者 GUOHan-Ying LIYu-Qi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第6期703-710,共8页
We introduce the Euler-Lagrange cohomology to study the symplectic and multisymplectic structures and their preserving properties in finite and infinite dimensional Lagrangian systems respectively. We also explore the... We introduce the Euler-Lagrange cohomology to study the symplectic and multisymplectic structures and their preserving properties in finite and infinite dimensional Lagrangian systems respectively. We also explore their certain difference discrete counterparts in the relevant regularly discretized finite and infinite dimensional Lagrangian systems by means of the difference discrete variational principle with the difference being regarded as an entire geometric object and the noncommutative differential calculus on regular lattice. In order to show that in all these cases the symplectic and multisymplectic preserving properties do not necessarily depend on the relevant Euler-Lagrange equations, the Euler-Lagrange cohomological concepts and content in the configuration space are employed. 展开更多
关键词 Euler-Lagrange cohomology difference discrete variational principle symplectic structure
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Genomic Signal Search by Dynamic Programming 被引量:2
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作者 ZHENGWei-Mon 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第6期761-764,共4页
A general and flexible multi-motif model is proposed based on dynamic programming. By extending theGibbs sampler to the dynamic programming and introducing temperature, an efficient algorithm is developed. Branchpoint... A general and flexible multi-motif model is proposed based on dynamic programming. By extending theGibbs sampler to the dynamic programming and introducing temperature, an efficient algorithm is developed. Branchpoint signalsequences and translation initiation sequences extracted from the rice genome are then examined. 展开更多
关键词 水稻 基因序列分析 信号分析 DNA 温度 产率 动态规划
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Relativistic Consistent Angular-Momentum Projected Shell-Model: Relativistic Mean Field 被引量:3
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作者 LIYan-Song LONGGui-Lu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第3期429-434,共6页
We develop a relativistic nuclear structure model, relativistic consistent angular-momentum projected shell-model (RECAPS), which combines the relativistic mean-field theory with the angular-momentum projection method... We develop a relativistic nuclear structure model, relativistic consistent angular-momentum projected shell-model (RECAPS), which combines the relativistic mean-field theory with the angular-momentum projection method. In this new model, nuclear ground-state properties are first calculated consistently using relativistic mean-field (RMF) theory. Then angular momentum projection method is used to project out states with good angular momentum from a few important configurations. By diagonalizing the hamiltonian, the energy levels and wave functions are obtained. This model is a new attempt for the understanding of nuclear structure of normal nuclei and for the prediction of nuclear properties of nuclei far from stability. In this paper, we will describe the treatment of the relativistic mean field. A computer code, RECAPS-RMF, is developed. It solves the relativistic mean field with axial-symmetric deformation in the spherical harmonic oscillator basis. Comparisons between our calculations and existing relativistic mean-field calculations are made to test the model. These include the ground-state properties of spherical nuclei <SUP>16</SUP>O and <SUP>208</SUP>Pb, the deformed nucleus <SUP>20</SUP>Ne. Good agreement is obtained. 展开更多
关键词 relativistic consistent angular-momentum projected shell-model relativistic mean field projected shell model PECAPS-RMF
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Single Boson Realizations of the Higgs Algebra 被引量:2
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作者 RUANDong WUChu SUNHong-Zhou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第1X期73-76,共4页
We obtained for the Higgs algebra three kinds of single boson realizations such as the unitary Holstein-Primakoff-like realization, the non-unitary Dyson-like realization, and the unitary Villain-like realization. Th... We obtained for the Higgs algebra three kinds of single boson realizations such as the unitary Holstein-Primakoff-like realization, the non-unitary Dyson-like realization, and the unitary Villain-like realization. The corre-sponding similarity transformations between the Holstein-Primakoff-like realizations and the Dyson-like realizations are given. 展开更多
关键词 希格斯介子代数 非线性角动量代数 玻色子 Higgs代数 多项式角动量代数 量子场论
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Spinor Decomposition of SU(2) Gauge Potential and Spinor Structures of Chern-Simons and Chern Density 被引量:2
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作者 DUANYi-Shi LIUXin FULi-Bin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第4X期447-450,共4页
In this paper, the decomposition of SU(2) gauge potential in terms of Pauli spinor is studied. Using this decomposition, the spinor structures of Chern Simons form and the Chern density are obtained. Furthermore, the ... In this paper, the decomposition of SU(2) gauge potential in terms of Pauli spinor is studied. Using this decomposition, the spinor structures of Chern Simons form and the Chern density are obtained. Furthermore, the knot quantum number of non-Abelian gauge theory can be expressed by the Chern-Simons spinor structure, and the second Chern number is characterized by the Hopf indices and the Brouwer degrees of Φ-mapping. 展开更多
关键词 旋量分解 自旋结构 泡利自旋 非阿贝尔规范理论 节量子数 规范势
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On Possible S-Wave Bound States for an N-↑N System Within a Constituent Quark Model 被引量:3
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作者 CHANGChao-Hsi PANGHou-Rong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期275-282,共8页
We try to apply a constituent quark model (a variety chiral constituent quark model) and the resonating group approach for the multi-quark problems to compute the effective potential between the NN- in S-wave (the qua... We try to apply a constituent quark model (a variety chiral constituent quark model) and the resonating group approach for the multi-quark problems to compute the effective potential between the NN- in S-wave (the quarks in the nucleons N and N-, and the two nucleons relatively as well, are in S wave) so as to see the possibility if there may be a tight bound state of six quarks as indicated by a strong enhancement at threshold of pp- in J/ψ and B decays. The effective potential which we obtain in terms of the model and approach shows if the experimental enhancement is really caused by a tight S-wave bound state of six quarks, then the quantum number of the bound state is very likely to be I = 1, JPC= 0-+. 展开更多
关键词 nucleon-antinucleon effective interaction multiquark system constituentquark model
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Search for Exotic Strange Dibaryon in Relativistic Heavy Ion Collisions 被引量:1
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作者 GAOChong-Shou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第2X期188-190,共3页
The exotic strange dibaryon particle (ΩΩ)0+ with S = -6 can be produced in relativistic heavy ion collisions. The yields of this kind of exotic strange dibaryon particles can increase signitlcantly soon as the forma... The exotic strange dibaryon particle (ΩΩ)0+ with S = -6 can be produced in relativistic heavy ion collisions. The yields of this kind of exotic strange dibaryon particles can increase signitlcantly soon as the formation of QGP does exhibit after the collision. If there is no phase transition after the collision, the upper bound of the production of this diomega can be estimated from the free hadronic gas model for nuclear matter. The relative yield ratio of diomega to deuteron is less than 0.000205, this means that if there is no QGP creation it is difficult to observe the production of diomega in relativistic heavy ion collisions. 展开更多
关键词 相对论重离子碰撞 QGP 奇异二重子 RHIC 相变 夸克-胶子等离子相位 强子物质
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Instantaneous Bethe-Salpeter Equation and Its Exact Solution 被引量:2
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作者 CHANGChao-Hsi CHENJiao-Kai +1 位作者 LIXue-Qia WANGGuo-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第1期113-118,共6页
We present an approach to solve Bethe-Salpeter (BS) equations exactly withoutany approximation if the kernel of the BS equations exactly is instantaneous, and take positroniumas an example to illustrate the general fe... We present an approach to solve Bethe-Salpeter (BS) equations exactly withoutany approximation if the kernel of the BS equations exactly is instantaneous, and take positroniumas an example to illustrate the general features of the exact solutions. The key step for theapproach is from the BS equations to derive a set of coupled and well-determined integrationequations in linear eigenvalue for the components of the BS wave functions equivalently, which maybe solvable numerically under a controlled accuracy, even though there is no analytic solution. Forpositronium, the exact solutions precisely present corrections to those of the correspondingSchrodinger equation in order υ~1 (υ is the relative velocity) for eigenfunctions, in order υ~2for eigenvalues, and the mixing between S and D components in J~(PC) = 1~(--) states etc.,quantitatively. Moreover, we also point out that there is a questionable step in some existentderivations for the instantaneous BS equations if one is pursuing the exact solutions. Finally, weemphasize that one should take the O(υ) corrections emerging in the exact solutions into accountaccordingly if one is interested in the relativistic corrections for relevant problems to the boundstates. 展开更多
关键词 instantaneous BS equation exact solutions POSITRONIUM relativisticcorrections
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Exploring High Strangeness Dibaryons with the Extended Quark Delocalization andColor Screening Model 被引量:4
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作者 PANGHou-Rong PINGJia-Lun +1 位作者 WANGFan ZHAOEn-Guang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第1期67-72,共6页
Promising high strangeness dibaryons are studied by the extended quark delocalization and color screeningmodel. It is shown that besides H particle and di-Ω, there might be other dibaryon candidates worth to be searc... Promising high strangeness dibaryons are studied by the extended quark delocalization and color screeningmodel. It is shown that besides H particle and di-Ω, there might be other dibaryon candidates worth to be searchedexperimentally such as NΩ. 展开更多
关键词 DIBARYON meson exchange
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Baryon Ratios in Quark-Gluon Plasma 被引量:1
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作者 MAZhong-Biao MIAOHong GAOChong-Shou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5X期547-550,共4页
A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavy ion collisions is presented. It is assumed that at the beginning of the hadronlzation there are diquarks and anti-diquarks in ... A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavy ion collisions is presented. It is assumed that at the beginning of the hadronlzation there are diquarks and anti-diquarks in the quark matter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays are taken into account. The results are shown at last. 展开更多
关键词 夸克-胶子等离子体 重子比例 定夸克 核聚变过程 多重态 高能物理学
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Contribution of Disclination Lines to Free Energy of Liquid Crystals in Single-Elastic Constant Approximation 被引量:1
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作者 YANGGuo-Hong WANGYu-Sheng DUANYi-Shi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第2X期185-188,共4页
In the light of φ-mapping method and topological current theory, the contribution of disclination lines to free energy density of liquid crystals is studied in the single-elastic constant approximation. It is pointed... In the light of φ-mapping method and topological current theory, the contribution of disclination lines to free energy density of liquid crystals is studied in the single-elastic constant approximation. It is pointed out that the total free energy density can be divided into two parts. One is the usual distorted energy density of director field around the disclination lines. The other is the free energy density of disclination lines themselves, which is shown to be centralized at the disclination lines and to be topologically quantized in the unit of kπ /2. The topological quantum numbers are determined by the Hopf indices and Brouwer degrees of the director field at the disclination lines, i.e. the disclination strengths. From the Lagrange's method of multipliers, the equilibrium equation and the molecular field of liquid crystals are also obtained. The physical meaning of the Lagrangian multiplier is just the distorted energy density. 展开更多
关键词 向错线 自由能 液晶 单弹性常数近似 拉格朗日多项式
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Study of the Bc—Meson Lifetime 被引量:2
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作者 CHANGChao-Hsi CHENShao-Long 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第1期57-60,共4页
We in terms of optical theorem estimate the lifetime of B<SUB>c</SUB> meson with the parameters which are determined by fitting the data for the lifetimes and inclusive semileptonic decays of various B and... We in terms of optical theorem estimate the lifetime of B<SUB>c</SUB> meson with the parameters which are determined by fitting the data for the lifetimes and inclusive semileptonic decays of various B and D mesons. In the estimation, we find that the bound-state effects are important, and take them into account carefully in the framework which attributes the effects to the effective masses of the decay heavy quarks in the inclusive processes. We also find that to B<SUB>c</SUB> lifetime the penguin contribution is enhanced due to possible interference between the penguin and the 'tree part' c<SUB>1</SUB>O<SUB>1</SUB> + c<SUB>2</SUB>O<SUB>2</SUB>. 展开更多
关键词 B-c meson LIFETIME
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Nucleon—Pair Shell Model:Magnetic Excitations for Ba Isotopes 被引量:1
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作者 LUOYan-An NINGPing-Zhi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第3期331-334,共4页
Magnetic excitations for Ba isotopes are discussed within the nucleon-pair shell model truncated in the SD subspace. With the SD pair determined by a surface- interaction, M1 transitions for are well fitted. The M1 a... Magnetic excitations for Ba isotopes are discussed within the nucleon-pair shell model truncated in the SD subspace. With the SD pair determined by a surface- interaction, M1 transitions for are well fitted. The M1 and M3 transitions for and are also predicted. It is shown that the statement, the collective magnetic properties are due to the orbital motion of nucleons, is approximately valid. 展开更多
关键词 the nucleon-pair shell model magnetic excitation Ba isotopes
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Whittaker Order Reduction Method of Relativistic Birkhoffian Systems 被引量:1
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作者 LUOShao-Kai HUANGFei-Jiang LUYi-Bing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第6X期817-820,共4页
The order reduction method of the relativistic Birkhoffian equations is studied. For a relativistic autonomous Birkhoffian system, if the conservative law of the Birkhoffian holds, the conservative quantity can be cal... The order reduction method of the relativistic Birkhoffian equations is studied. For a relativistic autonomous Birkhoffian system, if the conservative law of the Birkhoffian holds, the conservative quantity can be called the generalized energy integral. Through the generalized energy integral, the order of the system can be reduced. If the relativistic Birkhoffian system has a generalized energy integral, then the Birkhoffian equations can be reduced by at least two degrees and the Birkhoffian form can be kept. The relations among the relativistic Birkhoffian mechanics, the relativistic Hamiltonian mechanics and the relativistic Lagrangian mechanics are discussed, and the Whittaker order reduction method of the relativistic Lagrangian system is obtained. And an example is given to illustrate the application of the result. 展开更多
关键词 相对论 拉格朗日力学系统 能量积分 顺序约化法
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