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可控串联补偿(TCSC)系统感性微调区的Pitchfork分叉现象 被引量:3
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作者 刘晓冬 解大 陈陈 《中国电机工程学报》 EI CSCD 北大核心 1999年第12期1-4,69,共5页
叙述了可控串联补偿(TCSC) 装置在感性微调区工作的动态模拟实验结果,用Poincare 映射法分析了TCSC系统的动态稳定性。理论分析、EMTP数值仿真及动模实验均证明,超过一个临界触发角后,TCSC系统发生Pit... 叙述了可控串联补偿(TCSC) 装置在感性微调区工作的动态模拟实验结果,用Poincare 映射法分析了TCSC系统的动态稳定性。理论分析、EMTP数值仿真及动模实验均证明,超过一个临界触发角后,TCSC系统发生Pitchfork 展开更多
关键词 TCSC系统 感性微调区 pitchfork分叉 稳定性
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高维映射的Hopf-pitchfork分岔及其在碰撞振动系统中的应用 被引量:3
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作者 徐慧东 谢建华 《应用力学学报》 EI CAS CSCD 北大核心 2008年第2期268-273,共6页
研究了高维映射的Hopf-pitchfork分岔。通过中心流形理论,将高维映射降阶为一个三维映射,再通过范式方法将降阶后的三维映射转化为范式映射。理论分析了三维范式映射在Hopf-pitchfork分岔点附近的参数开折。通过对分岔点附近含间隙振动... 研究了高维映射的Hopf-pitchfork分岔。通过中心流形理论,将高维映射降阶为一个三维映射,再通过范式方法将降阶后的三维映射转化为范式映射。理论分析了三维范式映射在Hopf-pitchfork分岔点附近的参数开折。通过对分岔点附近含间隙振动系统的分岔行为进行数值仿真,验证了理论结果。 展开更多
关键词 映射 碰撞振动 Hopf-pitchfork分岔 混沌
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一类具时滞的BAM神经网络模型的Pitchfork分支
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作者 张明明 吕海波 张春蕊 《东北林业大学学报》 CAS CSCD 北大核心 2007年第2期73-75,共3页
研究了一个BAM神经网络模型的分支问题,证明了直线f′1(0)g′1(0)+f′2(0)g′2(0)=u2为一条Pitchfork分支曲线;并给出了分支曲线图,讨论了在由分支曲线划分的不同区域里平衡点的稳定性。
关键词 BAM神经网络 时滞 pitchfork分支
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初级纤毛相关基因Pitchfork在小鼠腭部发育中的表达模式及作用机制
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作者 金成日 玄云泽 +1 位作者 李龙和 李京旭 《延边大学医学学报》 CAS 2016年第2期92-94,共3页
[目的]研究初级纤毛相关基因Pitchfork在小鼠腭部发育中的表达模式及作用机制.[方法]取小鼠腭部发育不同时期的胚胎,采用石蜡切片和冰冻切片方法制作标本,使用免疫组织化学方法及原味杂交法检测Pitchfork在小鼠腭部发育中的表达.[结果]... [目的]研究初级纤毛相关基因Pitchfork在小鼠腭部发育中的表达模式及作用机制.[方法]取小鼠腭部发育不同时期的胚胎,采用石蜡切片和冰冻切片方法制作标本,使用免疫组织化学方法及原味杂交法检测Pitchfork在小鼠腭部发育中的表达.[结果]在小鼠腭部发育过程中,Pitchfork高表达于两侧腭突特定部位.[结论]Pitchfork在小鼠正常腭部发育中可能通过调节上皮细胞和间充质细胞及其相互调控发挥重要作用. 展开更多
关键词 腭部发育 pitchfork 小鼠
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一类三自由度碰撞振动系统的Hopf-pitchfork余维二分岔与混沌 被引量:2
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作者 彭珊 成龙 《机械强度》 CAS CSCD 北大核心 2014年第2期183-186,共4页
建立了一类三自由度振动碰撞系统的力学模型,推导了系统周期运动的解析解及Poincaré映射。基于六维Poincaré映射方法研究了系统的Hopf-pitchfork余维二分岔。在Hopf-pitchfork余维二分岔中先发生Pitchfork分岔,后发生Hopf分... 建立了一类三自由度振动碰撞系统的力学模型,推导了系统周期运动的解析解及Poincaré映射。基于六维Poincaré映射方法研究了系统的Hopf-pitchfork余维二分岔。在Hopf-pitchfork余维二分岔中先发生Pitchfork分岔,后发生Hopf分岔。系统通过概周期通向混沌的非常规道路揭示了在余维二分岔点附近的复杂动力学行为。 展开更多
关键词 Hopf-pitchfork分岔 POINCARE映射 周期运动
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Pitchfork bifurcation and circuit implementation of a novel Chen hyper-chaotic system 被引量:2
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作者 董恩增 陈增强 +1 位作者 陈在平 倪建云 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第3期92-100,共9页
In this paper, a novel four dimensional hyper-chaotic system is coined based on the Chen system, which contains two quadratic terms and five system parameters. The proposed system can generate a hyper-chaotic attracto... In this paper, a novel four dimensional hyper-chaotic system is coined based on the Chen system, which contains two quadratic terms and five system parameters. The proposed system can generate a hyper-chaotic attractor in wide parameters regions. By using the center manifold theorem and the local bifurcation theory, a pitchfork bifurcation is demonstrated to arise at the zero equilibrium point. Numerical analysis demonstrates that the hyper-cha^tic system can generate complex dynamical behaviors, e.g., a direct transition from quasi-periodic behavior to hyper-chaotic behavior. Finally, an electronic circuit is designed to implement the hyper-chaotic system, the experimental results are consist with the numerical simulations, which verifies the existence of the hyper-chaotic attractor. Due to the complex dynamic behaviors, this new hyper-cha^tic system is useful in the secure communication. 展开更多
关键词 HYPER-CHAOS Chen system pitchfork bifurcation center manifold theorem
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SOME DYNAMICAL PROPERTIES OF THE UNIVERSAL UNFOLDING OF PITCHFORK
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作者 Zhu, ZY Ding, R 《Acta Mechanica Solida Sinica》 SCIE EI 1995年第4期356-363,共8页
From the point of view of dynamics, the phenomenon of mode jumping in the imperfect pitchfork problem is discussed. The dynamical mechanism of model jumping of structures, such as plate and shell, that is brought abou... From the point of view of dynamics, the phenomenon of mode jumping in the imperfect pitchfork problem is discussed. The dynamical mechanism of model jumping of structures, such as plate and shell, that is brought about by the extremum instability, is explained. Finally, we give numerical simulation to show the validity of our results. 展开更多
关键词 pitchfork bifurcation universal unfolding dynamical system mode jumping
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Imperfect pitchfork bifurcation in asymmetric two-compartment granular gas
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作者 张因 李寅阊 +3 位作者 刘锐 崔非非 Pierre Evesque 厚美瑛 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第5期44-48,共5页
The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup. Unlike the random clustering in either compartment in the case of symmetric configuration when ... The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup. Unlike the random clustering in either compartment in the case of symmetric configuration when lowering the shaking strength to below a critical value, the directed clustering is observed, which corresponds to an imperfect pitchfork bifurcation. Numerical solutions of the flux equation using a modified simple flux function show qualitative agreements with the experimental results. The potential application of this asymmetric structure is discussed. 展开更多
关键词 compartmentalized granular gases directed clustering imperfect pitchfork bifurcation
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PITCHFORK BIFURCATION IN IODATE-ANSENOUS ACID REACTION
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作者 Ru Shing LI(Department of Chemistry, Tsinghua University, Beijing, 100084) 《Chinese Chemical Letters》 SCIE CAS CSCD 1994年第3期227-228,共2页
Based on the empirical rate law and the kinetic data reported in the literature, it is predicted that the iodate-arsenous acid reaction may exhibit pitchfork bifurcation phenomenon in CSTR with two inflows of the reac... Based on the empirical rate law and the kinetic data reported in the literature, it is predicted that the iodate-arsenous acid reaction may exhibit pitchfork bifurcation phenomenon in CSTR with two inflows of the reactants. 展开更多
关键词 ACID pitchfork BIFURCATION IN IODATE-ANSENOUS ACID REACTION
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Pitchfork分析法评估Twin—block矫治器治疗安氏Ⅱ^1错[牙合]的硬组织疗效 被引量:6
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作者 李新桂 叶金梅 +1 位作者 张栋杰 陈柯 《中华临床医师杂志(电子版)》 CAS 2014年第14期64-67,共4页
目的应用Pitchfork分析法研究排除自然生长因素后,Twin-block矫治器治疗替牙期或恒牙早期安氏Ⅱ1错引起的硬组织改变。方法选择15例安氏Ⅱ1下颌后缩患者,观察10个月作为自然生长对照组,随后采用Twin-block矫正器治疗,平均治疗约10个月... 目的应用Pitchfork分析法研究排除自然生长因素后,Twin-block矫治器治疗替牙期或恒牙早期安氏Ⅱ1错引起的硬组织改变。方法选择15例安氏Ⅱ1下颌后缩患者,观察10个月作为自然生长对照组,随后采用Twin-block矫正器治疗,平均治疗约10个月。对治疗及观察前后头颅侧位片进行Pitchfork测量分析,评价对照期和治疗期在平均功能性平面上骨骼及牙齿的位置变化的矫治疗效。结果在5.97 mm(P<0.01)的覆盖减少量和4.86 mm(P<0.01)的磨牙关系改善中,骨骼效应占41.2%和50.7%,牙齿效应分别占58.8%和49.3%,其中4.86 mm磨牙关系改善中,包括骨性改变2.46 mm、牙性改变2.40 mm,骨性改变中下颌骨贡献率约为81.7%。结论 Twin-block矫治器使发育期安氏Ⅱ1错牙患者覆盖、磨牙关系均得到较好改善,有效促进了下颌骨矢状方向上的生长发育,有利于Ⅱ类骨面型的纠正。 展开更多
关键词 错[牙合]安氏Ⅱ类 TWIN-BLOCK矫治器 pitchfork分析法
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一类pitchfork分支的全局相图 被引量:1
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作者 李时敏 Jaume Llibre 《中国科学:数学》 CSCD 北大核心 2019年第9期1201-1208,共8页
本文研究二次微分系统dt/dr=y^2?y?x,dy/dt=x^2?μx?y,其中μ∈R.该系统是刻画pitchfork分支的重要例子.本文给出该系统在Poincare圆盘上的全局相图。
关键词 相图 pitchfork分支 Poincaré紧致化
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CLASSIFICATION OF PITCHFORK BIFURCATIONS AND THEIR COMPUTATION
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作者 杨忠华 《Science China Mathematics》 SCIE 1989年第5期537-549,共13页
In this paper. the classification of the pitchfork bifurcation in nonlinear problems withseveral parameters is considered. The regular extended systems for the pitchfork bifurcationpoints with different singularity ar... In this paper. the classification of the pitchfork bifurcation in nonlinear problems withseveral parameters is considered. The regular extended systems for the pitchfork bifurcationpoints with different singularity are proposed. An efficient algorithm for solving the ex-tended systems is given. Finally, some numerical examples are shown to test the efficiencyof this algorithm. 展开更多
关键词 nonlinear problem with N parameters contact EQUIVALENCE pitchfork BIFURCATION of DEGREE N EXTENDED system.
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COMPUTATION OF HOPF BRANCHES BIFURCATING FROM A HOPF/PITCHFORK POINT FOR PROBLEMS WITH Z_2-SYMMETRY
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作者 Bai-sheng Wu (Department of Mathematics,Jilin University, Changchun 130023, China)Tassilo Kupper (Institute of Mathematics, University of Cologne, D-50931 Koln, Germany) 《Journal of Computational Mathematics》 SCIE CSCD 1998年第5期403-416,共14页
This paper is concerned with the computation of Hopf branches emanating from a Hopf/Pitchfork point in a two-parametor nonlinear problem satisfying a Z2symnletry condition. Our aim is to present a new al,proach to ... This paper is concerned with the computation of Hopf branches emanating from a Hopf/Pitchfork point in a two-parametor nonlinear problem satisfying a Z2symnletry condition. Our aim is to present a new al,proach to the theoretical and computational analysis of the bifurcating Hopf branches at this singular point by using the system designed to calculate Hopf points and exploring its symmetry. It is shown that a Hopf/Pitchfork point is a pitchfork bifurcation point in the system.Hence standard continuation and branch-switching can be used to compute these Hopf branches. In addition, an effect method based on the extended system of the singular points is developed for the computation of branch of secondary (nonsymmetric) Hopf points. The implementation of Newton's method for solving the extended system is also discussed. A numerical example is given.Keyworks: Hopf/Pitchfork point, Z2-symmetry, Hopf point, bifurcation, Extended system 展开更多
关键词 Hopf/pitchfork point Z_2-symmetry Hopf point BIFURCATION Extended system
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A HOMOTOPY METHOD OF SWITCHING SOLUTION BRANCHES AT THE PITCHFORK BIFURCATION POINT
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作者 Cong, Y.-H. Zhu, Z.-Y. 《Journal of Computational Mathematics》 SCIE EI CSCD 2001年第3期299-308,共10页
Provides information on a study which proposed a continuation method for switching solution branches at a pitchfork point. Problem of the standard pitchfork; Information on the systems of equations; Numerical examples... Provides information on a study which proposed a continuation method for switching solution branches at a pitchfork point. Problem of the standard pitchfork; Information on the systems of equations; Numerical examples of the efficiency of the proposed switching method. 展开更多
关键词 homotopy method switching solution branches pitchfork point
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Stable and non-symmetric pitchfork bifurcations
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作者 Enrique Pujals Michael Shub Yun Yang 《Science China Mathematics》 SCIE CSCD 2020年第9期1837-1852,共16页
In this paper,we present a criterion for pitchfork bifurcations of smooth vector elds based on a topological argument.Our result expands Rajapakse and Smale's result[15]signi cantly.Based on our criterion,we prese... In this paper,we present a criterion for pitchfork bifurcations of smooth vector elds based on a topological argument.Our result expands Rajapakse and Smale's result[15]signi cantly.Based on our criterion,we present a class of families of non-symmetric vector elds undergoing a pitchfork bifurcation. 展开更多
关键词 pitchfork bifurcation INDEX non-symmetric vector eld center manifold
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Local Dynamics Analysis of a Four-Dimensional Hyperchaotic Lorenz System
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作者 Yu Ren Liangqiang Zhou 《Journal of Applied Mathematics and Physics》 2023年第10期2789-2802,共14页
The local dynamical behaviors of a four-dimensional hyperchaotic Lorenz system, including stability and bifurcations, are investigated in this paper by analytical and numerical methods. The equilibriums and their stab... The local dynamical behaviors of a four-dimensional hyperchaotic Lorenz system, including stability and bifurcations, are investigated in this paper by analytical and numerical methods. The equilibriums and their stability under different parameter conditions are analyzed by applying Routh-Hurwitz criterion. The results indicate that the system may exist one, three and five equilibrium points for different system parameters. Based on the central manifold theorem and normal form theorem, the pitchfork bifurcation and Hopf bifurcation are studied respectively. By using the Hopf bifurcation theorem and calculating the first Lyapunov coefficient, the Hopf bifurcation of this system is obtained as supercritical for certain parameters. Finally, the results of theoretical parts are verified by some numerical simulations. 展开更多
关键词 Hyperchaotic Lorenz System STABILITY pitchfork Bifurcation Hopf Bifurcation Central Manifold
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一类双稳态复合材料层合板的簇发振荡现象分析
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作者 钱有华 杨园 《振动工程学报》 EI CSCD 北大核心 2023年第3期612-622,共11页
针对一类参数激励下的双稳态复合材料层合板非线性系统,考虑了一个参数激励频率是另一个的整数倍的情形,并将参数激励视为慢变参数,利用“快慢分析方法”得到了多频参数激励系统的快子系统和慢子系统,分析了快子系统的分岔行为。在平衡... 针对一类参数激励下的双稳态复合材料层合板非线性系统,考虑了一个参数激励频率是另一个的整数倍的情形,并将参数激励视为慢变参数,利用“快慢分析方法”得到了多频参数激励系统的快子系统和慢子系统,分析了快子系统的分岔行为。在平衡点分岔分析中,分析出单模和双模平衡点下快子系统的Hopf和fold分岔条件;利用双参数分岔集,相图、时间历程曲线图、转换相图与平衡分支的叠加图,分析了不同参数下簇发振荡的产生机理及其动力学行为,观察到不同的参数条件下其簇发振荡现象可能与叉形分岔点无关。 展开更多
关键词 簇发振荡 快慢分析方法 叉形分岔 转换相图 慢变参数
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具时滞的二维神经网络模型的分支 被引量:10
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作者 魏俊杰 张春蕊 李秀玲 《应用数学和力学》 CSCD 北大核心 2005年第2期193-200,共8页
 研究了一类具时滞的二维神经网络模型· 通过对该模型的特征方程根的分布分析,在适当的参数平面上给出了分支图· 得到了pitchfork分支曲线是一条直线,进而研究了每个平衡点的稳定性和Hopf分支的存在性· 最后,利用规...  研究了一类具时滞的二维神经网络模型· 通过对该模型的特征方程根的分布分析,在适当的参数平面上给出了分支图· 得到了pitchfork分支曲线是一条直线,进而研究了每个平衡点的稳定性和Hopf分支的存在性· 最后,利用规范性方法和中心流形理论。 展开更多
关键词 神经网络 中心流形 pitchfork分支 HOPF分支
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时滞BAM神经网络模型的稳定性分析 被引量:6
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作者 张明明 张春蕊 《生物数学学报》 CSCD 北大核心 2008年第2期257-264,共8页
本文研究了一个含有n+1个神经元的多时滞BAM型神经网络模型.利用儒歇定理及其推论分析了该动力特征方程根的分布情况,进而得到动力系统稳定和Hopf分支存在的条件,画出了分支图.研究了该动力系统的Pitchfork分支,得到了Pitchfork分支曲线... 本文研究了一个含有n+1个神经元的多时滞BAM型神经网络模型.利用儒歇定理及其推论分析了该动力特征方程根的分布情况,进而得到动力系统稳定和Hopf分支存在的条件,画出了分支图.研究了该动力系统的Pitchfork分支,得到了Pitchfork分支曲线,讨论了在分支曲线的不同区域里平衡点的稳定性. 展开更多
关键词 BAM神经网络 时滞 稳定性 HOPF分支 pitchfork分支
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一类封闭系统的混沌模型及其应用 被引量:1
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作者 肖健华 吴今培 陈世权 《五邑大学学报(自然科学版)》 CAS 2000年第4期23-27,共5页
提出了一类具有普遍意义的封闭系统的数学模型,详细讨论了该模型表现出来的复杂动力学特性. 通过对一个具体实例的数值计算和时序分析,结果表明:一般的迭代函数能产生混沌行为.
关键词 封闭系统 pitchfork分支 混沌 时序 LYAPUNOV指数
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