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Off-shell superpotentials and Ooguri-Vafa invariants of type Ⅱ/F theory compactification 被引量:1
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作者 徐锋军 杨富中 《Chinese Physics C》 SCIE CAS CSCD 2014年第3期12-17,共6页
In this paper,we calculate the off-shell superpotential of two Calabi-Yau manifolds with three parameters by integrating the period of the subsystem.We also obtain the Ooguri-Vafa invariants with open mirror symmetry.
关键词 superpotential mirror symmetry ooguri-vafa invariants
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Mirror symmetry,D-brane superpotentials and Ooguri-Vafa invariants of Calabi-Yau manifolds 被引量:1
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作者 张姗姗 杨富中 《Chinese Physics C》 SCIE CAS CSCD 2015年第12期7-12,共6页
The D-brane superpotential is very important in the low energy effective theory. As the generating function of all disk instantons from the worldsheet point of view, it plays a crucial role in deriving some important ... The D-brane superpotential is very important in the low energy effective theory. As the generating function of all disk instantons from the worldsheet point of view, it plays a crucial role in deriving some important properties of the compact Calabi Yau manifolds. By using the generalized GKZ hypergeometric system, we will calculate the D-brahe superpotentials of two non-Fermat type compact CMabi Yau hypersurfaces in toric varieties, respectively. Then according to the mirror symmetry, we obtain the A-model superpotentials and the Ooguri Vafa invariants for the mirror Calabi-Yau manifolds. 展开更多
关键词 D-brahe SUPERPOTENTIAL mirror symmetry ooguri-vafa invariant
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Accounting for Quadratic and Cubic Invariants in Continuum Mechanics–An Overview
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作者 Artur V.Dmitrenko Vladislav M.Ovsyannikov 《Fluid Dynamics & Materials Processing》 EI 2024年第9期1925-1939,共15页
The differential equations of continuum mechanics are the basis of an uncountable variety of phenomena and technological processes in fluid-dynamics and related fields.These equations contain derivatives of the first ... The differential equations of continuum mechanics are the basis of an uncountable variety of phenomena and technological processes in fluid-dynamics and related fields.These equations contain derivatives of the first order with respect to time.The derivation of the equations of continuum mechanics uses the limit transitions of the tendency of the volume increment and the time increment to zero.Derivatives are used to derive the wave equation.The differential wave equation is second order in time.Therefore,increments of volume and increments of time in continuum mechanics should be considered as small but finite quantities for problems of wave formation.This is important for calculating the generation of sound waves and water hammer waves.Therefore,the Euler continuity equation with finite time increments is of interest.The finiteness of the time increment makes it possible to take into account the quadratic and cubic invariants of the strain rate tensor.This is a new branch in hydrodynamics.Quadratic and cubic invariants will be used in differential wave equations of the second and third order in time. 展开更多
关键词 Quadratic invariant cubic invariant continuity equation generation of periodic waves N.E.Zhukovsky’s hydraulic shock TURBULENCE
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D-brane superpotentials and Ooguri-Vafa invariants of compact Calabi-Yau threefolds
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作者 徐锋军 杨富中 《Chinese Physics C》 SCIE CAS CSCD 2015年第4期19-25,共7页
We calculate the D-brane superpotentials for two compact Calabi-Yau manifolds X14(1,1,2,3,7) and Xs (1,1,1,2,3) which are of non-Fermat type in the type II string theory. By constructing the open mirror symmetry, ... We calculate the D-brane superpotentials for two compact Calabi-Yau manifolds X14(1,1,2,3,7) and Xs (1,1,1,2,3) which are of non-Fermat type in the type II string theory. By constructing the open mirror symmetry, we also compute the Ooguri-Vafa invariants, which are related to the open Gromov-Witten invariants. 展开更多
关键词 D-BRANE SUPERPOTENTIAL F-THEORY ooguri-vafa invariant
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Exact Invariants and Adiabatic Invariants of Nonholonomic Variable Mass Systems
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作者 陈向炜 梅凤翔 《Journal of Beijing Institute of Technology》 EI CAS 2001年第2期131-137,共7页
By the theory of symmetries and conserved quantities, the exact invariants and adiabatic invariants of nonholonomic variable mass systems are studied. The perturbation problem of symmetries for the nonholonomic variab... By the theory of symmetries and conserved quantities, the exact invariants and adiabatic invariants of nonholonomic variable mass systems are studied. The perturbation problem of symmetries for the nonholonomic variable mass systems under small excitation is discussed. The concept of high order adiabatic invariant is presented, and the form of exact invariants and adiabatic invariants as well as the conditions for their existence are given. Then the corresponding inverse problem is studied. 展开更多
关键词 analytical mechanics variable mass PERTURBATION adiabatic invariant
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Lie symmetries, perturbation to symmetries and adiabatic invariants of Poincaré equations 被引量:10
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作者 陈向炜 刘翠梅 李彦敏 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第3期470-474,共5页
Based on the invariance of differential equations under infinitesimal transformations, Lie symmetry, laws of conservations, perturbation to the symmetries and adiabatic invariants of Poincaré equations are presen... Based on the invariance of differential equations under infinitesimal transformations, Lie symmetry, laws of conservations, perturbation to the symmetries and adiabatic invariants of Poincaré equations are presented. The concepts of Lie symmetry and higher order adiabatic invariants of Poincaré equations are proposed. The conditions for existence of the exact invariants and adiabatic invariants are proved, and their forms are also given. In addition, an example is presented to illustrate these results. 展开更多
关键词 Poincaré equations perturbation to symmetry exact invariant adiabatic invariant
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Lie symmetrical perturbation and adiabatic invariants of generalized Hojman type for Lagrange systems 被引量:8
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作者 罗绍凯 陈向炜 郭永新 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3176-3181,共6页
Based on the invariance of differential equations under infinitesimal transformations of group, Lie symmetries, exact invariants, perturbation to the symmetries and adiabatic invariants in form of non-Noether for a La... Based on the invariance of differential equations under infinitesimal transformations of group, Lie symmetries, exact invariants, perturbation to the symmetries and adiabatic invariants in form of non-Noether for a Lagrange system are presented. Firstly, the exact invariants of generalized Hojman type led directly by Lie symmetries for a Lagrange system without perturbations are given. Then, on the basis of the concepts of Lie symmetries and higher order adiabatic invariants of a mechanical system, the perturbation of Lie symmetries for the system with the action of small disturbance is investigated, the adiabatic invariants of generalized Hojman type for the system are directly obtained, the conditions for existence of the adiabatic invariants and their forms are proved. Finally an example is presented to illustrate these results. 展开更多
关键词 Lagrange system Lie symmetrical perturbation exact invariant adiabatic invariant of generalized Hojman type
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A new type of adiabatic invariants for nonconservative systems of generalized classical mechanics 被引量:8
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作者 张毅 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第9期1935-1940,共6页
The perturbations to symmetries and adiabatic invariants for nonconservative systems of generalized classical mechanics axe studied. The exact inwriant in the form of Hojman from a particular Lie symmetry for an undis... The perturbations to symmetries and adiabatic invariants for nonconservative systems of generalized classical mechanics axe studied. The exact inwriant in the form of Hojman from a particular Lie symmetry for an undisturbed system of generalized mechanics is given. Based on the concept of high-order adiabatic invaxiant in generalized mechanics, the perturbation to Lie symmetry for the system under the action of small disturbance is investigated, and a new adiabatic invaxiant for the nonconservative system of generalized classical mechanics is obtained, which can be called the Hojman adiabatic invaxiant. An example is also given to illustrate the application of the results. 展开更多
关键词 generalized classical mechanics adiabatic invariant Lie symmetry PERTURBATION
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PERTURBATION OF SYMMETRIES OF BIRKHOFF SYSTEM AND ADIABATIC INVARIANTS 被引量:4
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作者 陈向炜 张睿超 梅凤翔 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2000年第3期282-288,共7页
The perturbation of symmetries of the free Birkhoff system under small excitation is discussed. The concept of high-order adiabatic invariant is presented, and the form of adiabatic invariants and the conditions for t... The perturbation of symmetries of the free Birkhoff system under small excitation is discussed. The concept of high-order adiabatic invariant is presented, and the form of adiabatic invariants and the conditions for their existence are given. Then these results are generalized to the constrained Birkhoff system. One example is presented to illustrate these results. 展开更多
关键词 Birkhoff system SYMMETRY PERTURBATION adiabatic invariants
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Exact invariants and adiabatic invariants of Raitzin's canonical equations of motion for a nonlinear nonholonomic mechanical system 被引量:6
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作者 乔永芬 李仁杰 孙丹姗 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第10期1919-1925,共7页
The exact invariants and the adiabatic invariants of Raitzin's canonical equations of motion for a nonlinear nonholonomic mechanical system are studied. The relations between the invariants and the symmetries of the ... The exact invariants and the adiabatic invariants of Raitzin's canonical equations of motion for a nonlinear nonholonomic mechanical system are studied. The relations between the invariants and the symmetries of the system are established. Based on the concept of higher-order adiabatic invariant of a mechanical system under the action of a small perturbation, the forms of the exact invariants and adiabatic invariants and the conditions for their existence are proved. Finally, the inverse problem of the perturbation to symmetries of the system is studied and an example is also given to illustrate the application of the results. 展开更多
关键词 nonholonomic system Raitzin's canonical equation SYMMETRY PERTURBATION exactinvariant adiabatic invariant
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Perturbation to Noether Quasi-Symmetry and Adiabatic Invariants for Nonholonomic Systems on Time Scales 被引量:3
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作者 Chuanjing Song 《Journal of Beijing Institute of Technology》 EI CAS 2019年第3期469-476,共8页
Perturbation to Noether quasi-symmetry and adiabatic invariants for the nonholonomic system on time scales are studied. Firstly, some properties of time scale calculus are reviewed. Secondly, the differential equation... Perturbation to Noether quasi-symmetry and adiabatic invariants for the nonholonomic system on time scales are studied. Firstly, some properties of time scale calculus are reviewed. Secondly, the differential equations of motion for the nonholonomic system on time scales, Noether quasi-symmetry and conserved quantity are given. Thirdly, perturbation to Noether quasi-symmetry and adiabatic invariants, which are the main results of this paper, are investigated. The main results are achieved by two steps, the first step is to obtain adiabatic invariants without transforming the time, and the next is to obtain adiabatic invariants under the infinitesimal transformations of both the time and the coordinates. And in the end, an example is given to illustrate the methods and results. 展开更多
关键词 PERTURBATION to NOETHER QUASI-SYMMETRY adiabatic invariant NONHOLONOMIC system time scale
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Target classification using SIFT sequence scale invariants 被引量:5
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作者 Xufeng Zhu Caiwen Ma +1 位作者 Bo Liu Xiaoqian Cao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第5期633-639,共7页
On the basis of scale invariant feature transform(SIFT) descriptors,a novel kind of local invariants based on SIFT sequence scale(SIFT-SS) is proposed and applied to target classification.First of all,the merits o... On the basis of scale invariant feature transform(SIFT) descriptors,a novel kind of local invariants based on SIFT sequence scale(SIFT-SS) is proposed and applied to target classification.First of all,the merits of using an SIFT algorithm for target classification are discussed.Secondly,the scales of SIFT descriptors are sorted by descending as SIFT-SS,which is sent to a support vector machine(SVM) with radial based function(RBF) kernel in order to train SVM classifier,which will be used for achieving target classification.Experimental results indicate that the SIFT-SS algorithm is efficient for target classification and can obtain a higher recognition rate than affine moment invariants(AMI) and multi-scale auto-convolution(MSA) in some complex situations,such as the situation with the existence of noises and occlusions.Moreover,the computational time of SIFT-SS is shorter than MSA and longer than AMI. 展开更多
关键词 target classification scale invariant feature transform descriptors sequence scale support vector machine
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Classification of MAG weld pool image based on moment invariants and fisher 被引量:4
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作者 高飞 王克鸿 +1 位作者 詹兰兰 张燕 《China Welding》 EI CAS 2011年第4期51-56,共6页
In order to discover characteristics of various kinds of weld pool image and identify a single image, seven image features are extracted to describe the corresponding surface formation quality by the moment iavariants... In order to discover characteristics of various kinds of weld pool image and identify a single image, seven image features are extracted to describe the corresponding surface formation quality by the moment iavariants method. An image feature matrix is composed by the seven characteristics. Then the matrix is projected on a line through the Fisher criterion in order to entirely distinguish various kinds of image features. And finally, transforming a seven-dimensional problem into a one-dimensional problem has been done. Compared with the three kinds of samples included in the arc welding process and quality weld pool visual image database, the images are classified into the three kinds such as superior weld formation in the condition of optimal gas flow, poor weld formation image in the condition of insuffwient gas flow, inferior weld formation in the condition of too low gas flow. Experiments show that the Fisher classification method based on moment invariants can recognize various weld pool images effectively, and it achieves a correct recognizable rate of 100%. 展开更多
关键词 weld pool image moment invariants Fisher criterion
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POINCARE-CARTAN INTEGRAL INVARIANTS OF BIRKHOFFIAN SYSTEMS 被引量:3
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作者 郭永新 尚玫 罗绍凯 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第1期68-72,共5页
Based on modern differential geometry, the symplectic structure of a Birkhoffian system which is an extension of conservative and nonconservative systems is analyzed. An integral invariant of Poincaré_Cartan... Based on modern differential geometry, the symplectic structure of a Birkhoffian system which is an extension of conservative and nonconservative systems is analyzed. An integral invariant of Poincaré_Cartan's type is constructed for Birkhoffian systems. Finally, one_dimensional damped vibration is taken as an illustrative example and an integral invariant of Poincaré's type is found. 展开更多
关键词 Birkhoffian systems symplectic structure self_adjointness Poincaré_Cartan integral invariants
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Perturbation to Mei symmetry and Mei adiabatic invariants for mechanical systems in phase space 被引量:2
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作者 张明江 方建会 +1 位作者 张小妮 路凯 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第6期1957-1961,共5页
For a perturbed mechanical system in phase space, considering d/dt in the structure equation and process of proof including infinitesimal parameter ε obviously, this paper studies the perturbation to Mei symmetry and... For a perturbed mechanical system in phase space, considering d/dt in the structure equation and process of proof including infinitesimal parameter ε obviously, this paper studies the perturbation to Mei symmetry and adiabatic invariants. Firstly, the exact invariant induced directly from the Mei symmetry of the system without perturbation is given. Secondly, based on the concept of high-order adiabatic invariant, the determining equations of the perturbation to Mei symmetry are established, the condition of existence of the Mei adiabatic invariant led by the perturbation to Mei symmetry is obtained, and its form is presented. Lastly, an example is given to illustrate the application of the results. 展开更多
关键词 Mei symmetry PERTURBATION adiabatic invariant mechanical system
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Perturbation of Symmetries and Hojman Adiabatic Invariants for Mechanical Systems with Unilateral Holonomic Constraints 被引量:4
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作者 ZHANG Yi FAN Cun-Xin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4期607-610,共4页
The perturbation of symmetries and adiabatic invariants for mechanical systems with unilateral holonomic constraints are studied. The exact invariant in the form of Hojman led by special Lie symmetries for an undistur... The perturbation of symmetries and adiabatic invariants for mechanical systems with unilateral holonomic constraints are studied. The exact invariant in the form of Hojman led by special Lie symmetries for an undisturbed system with unilateral constraints is given. Based on the concept of high-order adiabatic invariant of mechanical systems, the perturbation of Lie symmetries for the system under the action of small disturbance is investigated, and a new adiabatic invariant for the system with unilateral holonomic constraints is obtained, which can be called Hojman adiabatic invariant. In the end of the paper, an example is given to illustrate the application of the results. 展开更多
关键词 unilateral constraint Lie symmetry PERTURBATION exact invariant adiabatic invariant
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Hojman Exact Invariants and Adiabatic Invariants of Hamilton System 被引量:1
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作者 WANG Peng FANG Jian-Hui DING Ning ZHANG Xiao-Ni College of Physics Science and Technology,China University of Petroleum,Dongying 257061,China 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第12期996-998,共3页
The perturbation to Lie symmetry and adiabatic invariants are studied.Based on the concept of higher-order adiabatic invariants of mechanical systems with action of a small perturbation,the perturbation to Lie symmetr... The perturbation to Lie symmetry and adiabatic invariants are studied.Based on the concept of higher-order adiabatic invariants of mechanical systems with action of a small perturbation,the perturbation to Lie symmetryis studied,and Hojman adiabatic invariants of Hamilton system are obtained.An example is given to illustrate theapplication of the results. 展开更多
关键词 Hamilton system SYMMETRY exact invariant adiabatic invariant
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Lie Symmetrical Perturbation and Adiabatic Invariants of Generalized Hojman Type for Relativistic Birkhoffian Systems 被引量:4
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作者 LUO Shao-Kai GUO Yong-Xin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第1期25-30,共6页
For a relativistic Birkhoffian system, the Lie symmetrical perturbation and adiabatic invariants of generalized Bojman type are studied under general infinitesimal transformations. On the basis of the invariance of re... For a relativistic Birkhoffian system, the Lie symmetrical perturbation and adiabatic invariants of generalized Bojman type are studied under general infinitesimal transformations. On the basis of the invariance of relativistic Birkhotfian equations under general infinitesimal transformations,Lie symmetrical transformations of the system are constructed, which only depend on the Birkhoffian variables. The exact invariants in the form of generalized Hojman conserved quantities led by the Lie symmetries of relativistic Birkhoffian system without perturbations are given. Based on the definition of higher-order adiabatic invariants of a mechanical system, the perturbation of Lie symmetries for relativistic Birkhoffian system with the action of small disturbance is investigated, and a new type of adiabatic invariants of the system is obtained. In the end of the paper, an example is given to illustrate the application of the results. 展开更多
关键词 relativity BirkhofIian system Lie symmetrical perturbation exact invariant adiabatic invariant of generalized Hojman type
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Perturbation to Symmetries and Adiabatic Invariants of Nonholonomic System in Terms of Quasi-coordinates 被引量:4
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作者 CHEN Xiang-Wei ZHAO Yong-Hong LI Yan-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第5X期773-778,共6页
Based on the theory of Lie symmetries and conserved quantities, the exact invariants and adiabatic invariants of nonholonomic system in terms of quasi-coordinates are studied. The perturbation to symmetries for the no... Based on the theory of Lie symmetries and conserved quantities, the exact invariants and adiabatic invariants of nonholonomic system in terms of quasi-coordinates are studied. The perturbation to symmetries for the nonholonomic system in terms of quasi-coordinates under small excitation is discussed. The concept of high-order adiabatic invariant is presented, and the forms of exact invariants and adiabatic invariants as well as the conditions for their existence are given. Then the corresponding inverse problem is studied. 展开更多
关键词 nonholonomic system in terms of quasi-coordinates PERTURBATION exact invariant adiabatic invariant
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CLASSIFICATION OF MPSK SIGNALS USING CUMULANT INVARIANTS 被引量:20
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作者 Yang Shaoquan Chen Weidong (School of Electronic Engineering, Xidian University, Xi’an 710071) 《Journal of Electronics(China)》 2002年第1期99-103,共5页
A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and ca... A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and can suppress additive color or white Gaussian noise. Application of the new feature to classification of MPSK signals, at medium signal-to-noise ratio with specified sample size, results in high probability of correct identification. Finally, computer simulations and comparisons with existing algorithms are given. 展开更多
关键词 Higher order statistics Cumulant invariants Modulation classification
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