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超定线性系统最小二乘解的可信验证
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作者 于茜 李喆 《应用数学进展》 2021年第5期1598-1606,共9页
给定一个系数矩阵为病态矩阵的超定线性系统,本文利用区间算法和增广矩阵技术,设计算法输出给定超定线性系统的微小摄动区间系统,算法保证在输出的区间系统中存在系数阵精确秩亏的超定线性系统,算法输出该系数阵精确秩亏的超定线性系统... 给定一个系数矩阵为病态矩阵的超定线性系统,本文利用区间算法和增广矩阵技术,设计算法输出给定超定线性系统的微小摄动区间系统,算法保证在输出的区间系统中存在系数阵精确秩亏的超定线性系统,算法输出该系数阵精确秩亏的超定线性系统的最小二乘解的高精度近似解和其相应的可信误差界。 展开更多
关键词 可信验证 最小二乘解 线性系统
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二阶非线性具时滞脉冲微分方程振动性 被引量:4
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作者 毛卫华 《华南师范大学学报(自然科学版)》 CAS 2002年第1期45-51,共7页
主要就二阶非线性具时滞脉冲微分方程振动性进行了讨论 ,得到一些充分判据 ,并给出例子以说明脉冲及时滞对振动性态所起的作用 .
关键词 振动解 非振动解 超线性系统 线性系统 二阶非线性具时滞脉冲微分方程 振动性
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Superlattice Patterns in Coupled Turing Systems 被引量:1
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作者 刘富成 贺亚峰 潘宇扬 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期971-976,共6页
In this paper, superlattice patterns have been investigated by using a two linearly coupled Brusselator model. It is found that superlattice patterns can only be induced in the sub-system with the short wavelength. Th... In this paper, superlattice patterns have been investigated by using a two linearly coupled Brusselator model. It is found that superlattice patterns can only be induced in the sub-system with the short wavelength. Three different coupling methods have been used in order to investigate the mode interaction between the two Turing modes. It is proved in the simulations that interaction between activators in the two sub-systems leads to spontaneous formation of black eye pattern and/or white eye patterns while interaction between inhibitors leads to spontaneous formation of super-hexagonal pattern. It is also demonstrated that the same symmetries of the two modes and suitable wavelength ratio of the two modes should also be satisfied to form superlattice patterns. 展开更多
关键词 superlattice pattern turing instability mode interaction
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Super-harmonic resonance of gear transmission system under stick-slip vibration in high-speed train 被引量:4
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作者 HUANG Guan-hua XU Si-si +1 位作者 ZHANG Wei-hua YANG Cai-jin 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期726-735,共10页
This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with... This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with consideration on the factors including the time-varying system stiffness,the transmission error,the tooth backlash and the self-excited excitation of the wheel-set.The frequency-response equation of the system at super-harmonic resonance is obtained by the multiple scales method,and the stabilities of the system are analyzed using the perturbation theory.Complex nonlinear behaviors of the system including multi-valued solutions,jump phenomenon,hardening stiffness are found.The effects of the equivalent damping and the loads of the system under the stick-slip oscillation are analyzed.It shows that the change of the load can obviously influence the resonance frequency of the system and have little effect on the steady-state response amplitude of the system.The damping of the system has a negative effect,opposite to the load.The synthetic damping of the system composed of meshing damping and equivalent damping may be less than zero when the wheel-set has a large slippage,and the system loses its stability owing to the Hopf bifurcation.Analytical results are validated by numerical simulations. 展开更多
关键词 stick-slip vibration super-harmonic resonance Hopf bifurcation gear transmission system high-speed train
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A Study on the Structure of Linear Synchronous Motor for 600 km/h Very High Speed Train
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作者 Chan-Bae Park Byung-Song Lee 《Journal of Energy and Power Engineering》 2014年第2期374-378,共5页
Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is... Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is based on wheel-rail method, but it enables to overcome the speed limitation by adhesion because it is operated through a non-contact method using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility with the conventional railway systems. Therefore, a comparative analysis on electromagnetic characteristics according to the structural combinations on the stator-mover of LSM (linear synchronous motor) for VHST (very high speed train) maintaining the conventional wheel-rail method is conducted, and the structure of coreless superconducting LSM suitable for 600 km/h VHST is finally proposed in this paper. 展开更多
关键词 Very high speed train linear synchronous motor CORELESS SUPERCONDUCTIVITY wheel-rail.
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Asymptotically or super linear cooperative elliptic systems in the whole space 被引量:1
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作者 CHEN GuanWei MA ShiWang 《Science China Mathematics》 SCIE 2013年第6期1181-1194,共14页
Under the assumption that F is asymptotically or super linear as |U|→∞ with U = (u,v)∈R^2, we obtain the existence of ground state solutions of a class of cooperative elliptic systems in NN by using a variant g... Under the assumption that F is asymptotically or super linear as |U|→∞ with U = (u,v)∈R^2, we obtain the existence of ground state solutions of a class of cooperative elliptic systems in NN by using a variant generalized weak linking theorem for strongly indefinite problem developed by Schechter and Zou. To the best of our knowledge, there is no result published concerning the systems in the whole space N^N. 展开更多
关键词 cooperative elliptic systems asymptotically linear superlinear~ the whole space ground statesolutions
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Homoclinic orbits of first order discrete Hamiltonian systems with super linear terms 被引量:4
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作者 CHEN WenXiong YANG MinBo DING YanHeng 《Science China Mathematics》 SCIE 2011年第12期2583-2596,共14页
In this paper we consider the first order discrete Hamiltonian systems {x1(n+1)-x1(n)=Hx2(n,x(n)),x2(n)-x2(n-1)=Hx1(n,x(n)),where x(n) = (x2(n)x1(n))∑ R^2N, H(n,z) = 1/2S(n)z. z + R(n,z... In this paper we consider the first order discrete Hamiltonian systems {x1(n+1)-x1(n)=Hx2(n,x(n)),x2(n)-x2(n-1)=Hx1(n,x(n)),where x(n) = (x2(n)x1(n))∑ R^2N, H(n,z) = 1/2S(n)z. z + R(n,z) is periodic in n and superlinear as {z} →4 ∞. We prove the existence and infinitely many (geometrically distinct) homoclonic orbits of the system by critical point theorems for strongly indefinite functionals. 展开更多
关键词 homoclinic orbits first order discrete Hamiltonian systems super linear critical points
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Acoustic Emission Source Linear Localization Based on an Ultra-Short FBGs Sensing System 被引量:1
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作者 Zhongwei JIN Mingshun JIANG Qingmei SUI Faye ZHANG Lei JIA 《Photonic Sensors》 SCIE EI CAS 2014年第2期152-155,共4页
An acoustic emission (AE) linear location system was proposed, which employed fiber Bragg gratings (FBGs) as AE sensors. It was demonstrated that the FBG wavelength could be modulated as the static case when the g... An acoustic emission (AE) linear location system was proposed, which employed fiber Bragg gratings (FBGs) as AE sensors. It was demonstrated that the FBG wavelength could be modulated as the static case when the grating length was much shorter than the AE wavelength. In addition, an improved AE location method based on the Gabor wavelet transform (WT) and threshold analysis was represented. The method was testified through AE linear location experiments based on a tunable narrow-band laser interrogation system using ultra-short FBG sensors as AE sensors. Results of the experiments showed that 86% of the linear location errors were less than 10mm. 展开更多
关键词 Acoustic emission (AE) linear location fiber Bragg gratings (FBGs) Gabor wavelet transform (WT) threshold analysis
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THE CONVERGENCE OF A NEW MODIFIED BFGS METHOD WITHOUT LINE SEARCHES FOR UNCONSTRAINED OPTIMIZATION OR COMPLEXITY SYSTEMS
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作者 Liying LIU Zengxin WEI Xiaoping WU 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2010年第4期861-872,共12页
In this paper,a new modified BFGS method without line searches is proposed.Unlike traditionalBFGS method,this modified BFGS method is proposed based on the so-called fixed steplengthstrategy introduced by Sun and Zhan... In this paper,a new modified BFGS method without line searches is proposed.Unlike traditionalBFGS method,this modified BFGS method is proposed based on the so-called fixed steplengthstrategy introduced by Sun and Zhang.Under some suitable assumptions,the global convergence andthe superlinear convergence of the new algorithm are established,respectively.And some preliminarynumerical experiments,which shows that the new Algorithm is feasible,is also reported. 展开更多
关键词 BFGS method complexity systems global convergence superlinear convergence unconstrained optimization.
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Existence of solutions for sub-linear or super-linear operator equations
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作者 CHEN YingYing DONG YuJun SHAN Yuan 《Science China Mathematics》 SCIE CSCD 2015年第8期1653-1664,共12页
We investigate solutions to superlinear or sublinear operator equations and obtain some abstract existence results by minimax methods. These results apply to superlinear or sublinear Hamiltonian systems satisfying sev... We investigate solutions to superlinear or sublinear operator equations and obtain some abstract existence results by minimax methods. These results apply to superlinear or sublinear Hamiltonian systems satisfying several boundary value conditions including Sturm-Liouville boundary value conditions and generalized periodic boundary value conditions, and yield some new theorems concerning existence of solutions or nontrivial solutions. In particular, some famous results about periodic solutions to superlinear or sublinear Hamiltonian systems by Rabinowitz or Benci and Rabinowitz are special cases of the theorems. 展开更多
关键词 SUPERLINEAR SUBLINEAR operator equations existence of solutions minimax methods Hamiltoniansystems
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