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On the Inverse Limit of Higson Compactifications 被引量:1
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作者 曹阳 孙以丰 《Northeastern Mathematical Journal》 CSCD 2002年第2期95-98,共4页
Higson have introduced the conception of "Higson’s corona" (see [1]). For a given metric space X, it is a kind of compactification of X related to the metric d on it. Denote by BR(X) the set {y ∈ X\d(x,y) ... Higson have introduced the conception of "Higson’s corona" (see [1]). For a given metric space X, it is a kind of compactification of X related to the metric d on it. Denote by BR(X) the set {y ∈ X\d(x,y) < R}. Recall that a slowly oscillating function on X is a function f G C*(X) satisfying the following condition: 展开更多
关键词 Stone-Cech corapactification Higson compactification coarse equivalent
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Resolvable Spaces and Compactifications
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作者 Monerah Al-Hajri Karim Belaid 《Advances in Pure Mathematics》 2013年第3期365-367,共3页
This paper deals with spaces such that their compactification is a resolvable space. A characterization of space such that its one point compactification (resp. Wallman compactification) is a resolvable space is given.
关键词 RESOLVABLE SPACE Alexandroff compactification Wallman compactification
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A&zeta;x- and Open <i>C<sub>D</sub><sup>*</sup></i>-Filters Process of Compactifications and Any Hausdorff Compactification
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作者 Hueytzen J. Wu Wan-Hong Wu 《Advances in Pure Mathematics》 2012年第4期296-300,共5页
By means of a characterization of compact spaces in terms of open CD*-filters induced by a , a - and open CD*-filters process of compactifications of an arbitrary topological space Y is obtained in Sec. 3 by embedding... By means of a characterization of compact spaces in terms of open CD*-filters induced by a , a - and open CD*-filters process of compactifications of an arbitrary topological space Y is obtained in Sec. 3 by embedding Y as a dense subspace of , YS = {ε |ε is an open CD*-filter that does not converge in Y}, YT = {A|A is a basic open CD*-filter that does not converge in Y}, is the topology induced by the base B = {U*|U is open in Y, U ≠φ} and U* = {F∈Ysw (or YTw)|U∈F}. Furthermore, an arbitrary Hausdorff compactification (Z, h) of a Tychonoff space X?can be obtained from a by the?similar process in Sec.3. 展开更多
关键词 Net OPEN FILTER OPEN CD*-Filter Base Basic OPEN CD*-Filter OPEN CD*-Filter -Filter x-Filter Tychonoff Space Normal T1-Space Compact Space compactificationS Stone-Cech compactification Wallman compactification
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Proof That Spatial Transitions Release/Absorb Energy That Compactification Necessarily Leads to Changes in Volume, Energy and Entropy
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作者 Christopher Pilot 《Journal of High Energy Physics, Gravitation and Cosmology》 2019年第2期310-320,共11页
Using simple box quantization, we demonstrate explicitly that a spatial transition will release or absorb energy, and that compactification releases latent heat with an attendant change in volume and entropy. Increasi... Using simple box quantization, we demonstrate explicitly that a spatial transition will release or absorb energy, and that compactification releases latent heat with an attendant change in volume and entropy. Increasing spatial dimension for a given number of particles costs energy while decreasing dimensions supplies energy, which can be quantified, using a generalized version of the Clausius-Clapyeron relation. We show this explicitly for massive particles trapped in a box. Compactification from N -dimensional space to (N - 1) spatial dimensions is also simply demonstrated and the correct limit to achieve a lower energy result is to take the limit, Lw → 0, where Lw is the compactification length parameter. Higher dimensional space has more energy and more entropy, all other things being equal, for a given cutoff in energy. 展开更多
关键词 SPATIAL TRANSITIONS Box Quantization compactification
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QUOTIENT SPACE OF LMC-COMPACTIFICATION AS A SPACE OF z-FILTERS
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作者 Mohammad Akbari Tootkaboni 《Acta Mathematica Scientia》 SCIE CSCD 2012年第5期2010-2020,共11页
The left multiplicative continuous compactification is the universal semigroup compactification of a semitopological semigroup.In this paper an internal construction of a quotient space of the left multiplicative cont... The left multiplicative continuous compactification is the universal semigroup compactification of a semitopological semigroup.In this paper an internal construction of a quotient space of the left multiplicative continuous compactification of a semitopological semigroup is constructed as a space of z-filters 展开更多
关键词 LMC-compactification z-filters quotient space
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An Expository on Some Nonstandard Compactifications
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作者 Alagu Somasundaram Rukhmoni Kala 《Advances in Pure Mathematics》 2021年第10期807-815,共9页
Three classical compactification procedures are presented with nonstandard flavour. This is to illustrate the applicability of Nonstandard analytic tool to beginners interested in Nonstandard analytic methods. The gen... Three classical compactification procedures are presented with nonstandard flavour. This is to illustrate the applicability of Nonstandard analytic tool to beginners interested in Nonstandard analytic methods. The general procedure is as follows: A suitable equivalence relation is defined on an enlargement <sup>*</sup><em>X </em>of the space <em>X</em> which is a completely regular space or a locally compact Hausdorff space or a locally compact Abelian group. Accordingly, every <em>f</em> in <em>C</em>(<em>X</em>,<em>R</em>) (the space of bounded continuous real valued functions on <em>X</em>) or <em>Cc</em>(<em>X</em>,<em>R</em>) (the space of continuous real valued functions on <em>X</em> with compact support) or the dual group <span style="white-space:nowrap;">&#915; </span>of the locally compact Abelian group <em>G</em> is extended to the set <img alt="" src="Edit_b9535172-924d-44f0-bab3-c49db17a3b7a.png" /> of the above mentioned equivalence classes. A compact topology on <img alt="" src="Edit_9d7962a3-b8a3-4693-b62a-078c8c4b4853.png" /> is obtained as the weak topology generated by these extensions of <em>f</em>. Then <em>X</em> is naturally imbedded densely in <img alt="" src="Edit_f7d403b2-eff3-4555-b8e7-1b106e06d2e7.png" />. 展开更多
关键词 Non-Standard compactification Completely Regular Space Locally Compact Hausdorff Space Locally Compact Abelian Group
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基于Poincaré映射的单相并网逆变器非线性动力学分析方法研究
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作者 汤晨煜 解大 +1 位作者 张延迟 古丽扎提·海拉提 《电气自动化》 2024年第5期76-78,共3页
近年来,并网逆变器作为电力系统与新能源的接口迅速发展,但目前线性化思想分析其稳定性问题的方法存在准确性不足的风险。为此,提出了一种基于Poincaré映射的单相并网逆变器非线性动力学分析方法。首先,考虑锁相环与电路的拓扑结构... 近年来,并网逆变器作为电力系统与新能源的接口迅速发展,但目前线性化思想分析其稳定性问题的方法存在准确性不足的风险。为此,提出了一种基于Poincaré映射的单相并网逆变器非线性动力学分析方法。首先,考虑锁相环与电路的拓扑结构,建立系统的非线性状态空间模型;其次,根据系统的拓扑切换方式求解系统的Poincaré映射,并对系统雅可比矩阵进行特征值求解;最后,对不同电容参数下的系统进行了特征值计算与仿真分析,仿真结果证明了分析方法的有效性。所提方法可以准确预测系统的非线性动力学行为,为并网逆变器的参数设计与理论分析提供帮助。 展开更多
关键词 poincarÉ映射 非线性 并网逆变器 锁相环
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More Compactification for Differential Systems
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作者 Harry Gingold Daniel Solomon 《Advances in Pure Mathematics》 2013年第1期190-203,共14页
This article is a review and promotion of the study of solutions of differential equations in the “neighborhood of infinity” via a non traditional compactification. We define and compute critical points at infinity ... This article is a review and promotion of the study of solutions of differential equations in the “neighborhood of infinity” via a non traditional compactification. We define and compute critical points at infinity of polynomial autonomuos differential systems and develop an explicit formula for the leading asymptotic term of diverging solutions to critical points at infinity. Applications to problems of completeness and incompleteness (the existence and nonexistence respectively of global solutions) of dynamical systems are provided. In particular a quadratic competing species model and the Lorentz equations are being used as arenas where our technique is applied. The study is also relevant to the Painlevé property and to questions of integrability of dynamical systems. 展开更多
关键词 Nonlinear Polynomial compactification Ultra Extended Euclidean Space CRITICAL POINT Equilibrium POINT CRITICAL POINT at INFINITY CRITICAL Direction at INFINITY BASIN of Divergence BASIN of Convergence Ideal Solutions Asymptotic Stability Global Globally Asymptotically Stable Jacobian Painleve Analysis Competing Species Model Lorenz Equations Periodic Surface Differential Geometry Attractor REPELLER
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Extra Time Dimension: Deriving Relativistic Space-Time Transformations, Kinematics, and Example of Dimensional Compactification Using Time-Dependent Non-Relativistic Quantum Mechanics
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作者 Sajjad Zahir 《Journal of Modern Physics》 2023年第10期1333-1354,共22页
We consider a five-dimensional Minkowski space with two time dimensions characterized by distinct speeds of causality and three space dimensions. Formulas for relativistic coordinate and velocity transformations are d... We consider a five-dimensional Minkowski space with two time dimensions characterized by distinct speeds of causality and three space dimensions. Formulas for relativistic coordinate and velocity transformations are derived, leading to a new expression for the speed limit. Extending the ideas of Einstein’s Theory of Special Relativity, concepts of five-velocity and five-momenta are introduced. We get a new formula for the rest energy of a massive object. Based on a non-relativistic limit, a two-time dependent Schrödinger-like equation for infinite square-well potential is developed and solved. The extra time dimension is compactified on a closed loop topology with a period matching the Planck time. It generates interference of additional quantum states with an ultra-small period of oscillation. Some cosmological implications of the concept of four-dimensional versus five-dimensional masses are briefly discussed, too. 展开更多
关键词 Two-Time Physics Special Theory of Relativity Kaluza-Klein Theory Time-Dependent Schrödinger Equation compactification
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Effects of Compactification on Free Massive Scalar Fields in Five-Dimensional Space-Time with an Extra Time Dimension: Analysing Some Results
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作者 Sajjad Zahir 《Journal of Modern Physics》 2023年第12期1600-1616,共17页
This paper deals with some aspects of two-time physics (i.e., 2T + 3S five-dimensional space) for a Minkowski-like space with distinct speeds of causality for the time dimensions. Detailed calculations are provided to... This paper deals with some aspects of two-time physics (i.e., 2T + 3S five-dimensional space) for a Minkowski-like space with distinct speeds of causality for the time dimensions. Detailed calculations are provided to obtain results of Kaluza-Klein type compactification for free massive scalar fields and abelian free gauge fields. As already indicated in the literature, a tower of massive fields results from the compactification with mass terms having signs opposite to those of the ones appearing in other five-dimensional theories with an extra space dimension. We perform elaborate numerical calculations to highlight the magnitude of the imaginary masses and ask if we need to explore alternative compactification techniques. 展开更多
关键词 Two-Time Physics Theory of Special Relativity Kaluza-Klein Theory compactification Klein-Gordon Equation TACHYONS Abelian Gauge Theory
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A Modified Wallman Method of Compactification
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作者 Hueytzen J.Wu Wan-Hong Wu 《Advances in Pure Mathematics》 2013年第6期590-597,共8页
Closed and basic closed C*D-filters are used in a process similar to Wallman method for compactifications of the topological spaces Y, of which, there is a subset of C*(Y) containing a non-constant function, where C*(... Closed and basic closed C*D-filters are used in a process similar to Wallman method for compactifications of the topological spaces Y, of which, there is a subset of C*(Y) containing a non-constant function, where C*(Y) is the set of bounded real continuous functions on Y. An arbitrary Hausdorff compactification (Z,h) of a Tychonoff space X can be obtained by using basic closed C*D-filters from in a similar way, where C(Z) is the set of real continuous functions on Z. 展开更多
关键词 Closed █_(x)-Filter Open and Closed C^(*)_(D)-Filter Bases Basic Open and Closed C^(*)_(D)-Filters compactification Stone-Cech and Wallman compactifications
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A Inherent Characterization of L-fuzzy Compactification
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作者 孟培源 周武能 《湖北科技学院学报》 1994年第1期1-9,共9页
AInherentCharacterizationofL-fuzzyCompactification¥Mengpeiyuan(XianningTeachers'College,Hubei,China)Zhouwune... AInherentCharacterizationofL-fuzzyCompactification¥Mengpeiyuan(XianningTeachers'College,Hubei,China)Zhouwuneng(YunyangTeacher... 展开更多
关键词 α-ultra-closed filter Nice-compactness T_(1)-seperation L-fuzzy topological space compactification
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Poincare映射的数值算法及其在永磁同步电机混沌分析中的应用 被引量:30
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作者 张波 李忠 +1 位作者 毛宗源 庞敏熙 《控制理论与应用》 EI CAS CSCD 北大核心 2001年第5期796-800,共5页
给出了Poincare映射的一个数值算法 ,并在提出的永磁同步电机 (PMSM )混沌模型的基础上 ,应用Poincare映射分析了PMSM的混沌现象 .仿真结果表明Poincare映射可以更直观地反映其相应的状态空间图形 ,而从一个新的角度证实了PMSM的混沌运... 给出了Poincare映射的一个数值算法 ,并在提出的永磁同步电机 (PMSM )混沌模型的基础上 ,应用Poincare映射分析了PMSM的混沌现象 .仿真结果表明Poincare映射可以更直观地反映其相应的状态空间图形 ,而从一个新的角度证实了PMSM的混沌运动的存在性 . 展开更多
关键词 poincarE映射 永磁同步电机 混沌 数值算法
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基于Poincare变换的滑动轴承非线性油膜力数据库方法 被引量:35
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作者 孟志强 徐华 朱均 《摩擦学学报》 EI CAS CSCD 北大核心 2001年第3期223-227,共5页
运用状态空间 Poincare变换使径向滑动轴承动力系统的部分状态变量由无限区间变换到有限区间 .在经过变换的状态空间中求解 Reynolds方程 ,建立了径向滑动轴承非线性油膜力数据库及相应的插值拟合程序 ,实现了非线性油膜力的快速准确获... 运用状态空间 Poincare变换使径向滑动轴承动力系统的部分状态变量由无限区间变换到有限区间 .在经过变换的状态空间中求解 Reynolds方程 ,建立了径向滑动轴承非线性油膜力数据库及相应的插值拟合程序 ,实现了非线性油膜力的快速准确获得 .通过滑动轴承 -转子系统运动瞬态分析和 展开更多
关键词 滑动轴承 非线性油膜力 poincare变换 数据库
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心率的Poincare散点图量化指标 被引量:16
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作者 徐征 葛霁光 +1 位作者 徐秋萍 张辉 《生物医学工程学杂志》 EI CAS CSCD 北大核心 2000年第4期433-436,共4页
Poincare散点图是非线性研究的重要方法之一 ,它可以有效地描述吸引子的形状 ,以往的研究大多停留在图形样式的角度上 ,这给研究带来了描述上的不确定和应用上的不便。因此我们在散点图图形基础上提取出四个定量参数 ,它们是散点图面积... Poincare散点图是非线性研究的重要方法之一 ,它可以有效地描述吸引子的形状 ,以往的研究大多停留在图形样式的角度上 ,这给研究带来了描述上的不确定和应用上的不便。因此我们在散点图图形基础上提取出四个定量参数 ,它们是散点图面积、长轴、短轴和角度。并根据心率的散点图特点 ,研究出较有效的“龟爬行计数法”将四个定量参数在计算机上得以实现。将四个定量参数应用于临床冠脉病变患者的心率变异研究上 ,发现这四个定量参数可以很好地描述散点图 ,也具有一定的特异性 ,提示这有很好的临床应用价值。 展开更多
关键词 心率 poincarE散点图 定量参数
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心率变异性Poincare散点图分析与BIS对麻醉深度监测的相关性研究 被引量:12
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作者 李佩 申岱 +1 位作者 贾晓宁 诸葛万银 《临床麻醉学杂志》 CAS CSCD 北大核心 2011年第2期116-118,共3页
目的观察全身麻醉时心率变异性分析中散点图分析和脑电双频指数(BIS)的变化,探讨散点图分析和BIS在监测麻醉深度时的相关性。方法选择ASAⅠ或Ⅱ级择期手术患者28例,测定手术前一天(T1)、麻醉诱导前(T2)、诱导插管(T3)、手术开始1h(T4)... 目的观察全身麻醉时心率变异性分析中散点图分析和脑电双频指数(BIS)的变化,探讨散点图分析和BIS在监测麻醉深度时的相关性。方法选择ASAⅠ或Ⅱ级择期手术患者28例,测定手术前一天(T1)、麻醉诱导前(T2)、诱导插管(T3)、手术开始1h(T4)、苏醒时(T5)、术后1d(T6)6个时点各5min的HR、MAP、散点图的短轴(SD1)、长轴(SD2)的变化以及T2~T5时BIS变化。结果与T1时比较,T6时MAP、SD2明显下降(P<0.05)。与T2时比较,T3时HR明显增快、MAP、SD2明显升高(P<0.01);T4、T5时MAP、SD2明显下降(P<0.05或P<0.01);T3~T5时BIS、SD1明显下降(P<0.01)。结论心率变异性非线性分析SD1能描述围术期心脏自主神经功能状态的变化,与反应麻醉镇静程度的BIS有很好的相关性。 展开更多
关键词 poincarE散点图 脑电双频指数 全身麻醉 心率变异性
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采用周期轨Poincaré映射的非线性电力电子系统小干扰稳定性分析 被引量:6
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作者 王刚 范学鑫 +2 位作者 付立军 纪锋 马海鑫 《中国电机工程学报》 EI CSCD 北大核心 2012年第1期84-92,14,共9页
拓扑结构切换、占空比控制方法和非线性元件均可使电力电子系统具有非线性特性,因此其小干扰稳定问题属于微分方程周期轨的稳定问题。由于状态空间平均法误差较大、难以预测分叉,而数值仿真法物理概念不清晰,因此,提出了基于梯形积分法... 拓扑结构切换、占空比控制方法和非线性元件均可使电力电子系统具有非线性特性,因此其小干扰稳定问题属于微分方程周期轨的稳定问题。由于状态空间平均法误差较大、难以预测分叉,而数值仿真法物理概念不清晰,因此,提出了基于梯形积分法的非线性电力电子系统周期轨稳定性分析方法。利用梯形积分法描述系统占空比方程和每阶段的非线性状态方程,由隐函数求导法和链式求导法计算周期轨Poincaré映射的雅可比(Jacobian)矩阵,提出了系统稳定裕度指标,建立了基于周期轨Poincaré映射的非线性电力电子系统小干扰稳定性分析方法。该方法能够克服小干扰稳定传统分析方法的困难,揭示非线性电力电子系统失稳的动力系统机制。仿真分析验证了算法的有效性。 展开更多
关键词 非线性电力电子系统 小干扰稳定性 周期轨 poincarÉ映射
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Hill区域内基于推广的Poincar映射的低能逃逸/捕捉轨道(英文) 被引量:3
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作者 周军 蔡力 周凤岐 《宇航学报》 EI CAS CSCD 北大核心 2007年第3期643-647,共5页
给出了Hill区域内基于推广的Poincar映射的低能逃逸轨道的计算。文中的推广的Poincar映射需要在相空间中选取两个(而非一个)与流相截的面,即将包含某个天平动点的截面通过轨道来映射到近拱点的通道面上的,在数值上通过总变差减小的Runge... 给出了Hill区域内基于推广的Poincar映射的低能逃逸轨道的计算。文中的推广的Poincar映射需要在相空间中选取两个(而非一个)与流相截的面,即将包含某个天平动点的截面通过轨道来映射到近拱点的通道面上的,在数值上通过总变差减小的Runge-Kutta方法来实现两个相面之间的映射。捕捉轨道则可由Hill三体模型的对称性直接导出。最后,关于Rhea的二维、三维的逃逸和捕捉轨道的仿真结果验证了该方法的精度和鲁棒性。 展开更多
关键词 三体问题 Hill区域 poincar映射
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不同程度冠心病患者心率变异性及Poincare散点图分析 被引量:5
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作者 干岭 郑林林 韩卫星 《安徽医学》 2003年第5期12-15,共4页
目的 探讨不同程度冠心病患者心率变异性 (HRV)及Poincare散点图的变化特征。方法 选择住院病人 14 2例 ,其中 ,冠心病组 5 2例 ,陈旧性心肌梗死组 60例 ,将冠脉造影阴性的 3 0例患者作为对照组。对性别、年龄、血压、血糖、尿酸、胆... 目的 探讨不同程度冠心病患者心率变异性 (HRV)及Poincare散点图的变化特征。方法 选择住院病人 14 2例 ,其中 ,冠心病组 5 2例 ,陈旧性心肌梗死组 60例 ,将冠脉造影阴性的 3 0例患者作为对照组。对性别、年龄、血压、血糖、尿酸、胆固醇、甘油三脂、2 4hHRV的部分时域指标及Poincare散点图进行统计学分析和比较。结果 病例组与对照组相比 ,年龄增大 ,男性患者及合并高血压、高血糖、高尿酸、高甘油三脂的患者比率明显增高 ,HRV中的SDNN、彗星状散点图比率及定量指标VLI明显降低。随着冠脉病变程度的加重 ,SDNN、VLI及彗星状散点图比率进行性降低 ,较临床指标改变明显。结论 提示冠心病患者伴有心脏自主神经功能损害 ,并随着冠脉病变程度的加重而加重 ,二者互为影响 。 展开更多
关键词 冠心病 心率变异性 poincarE散点图 统计学分析 心电图
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采用Poincaré映射分析含裂纹转子的非协调响应 被引量:5
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作者 贺尔铭 秦卫阳 +1 位作者 魏道德 任兴民 《西北工业大学学报》 EI CAS CSCD 北大核心 2003年第3期277-280,共4页
由 Poincaré映射不动点的稳定性理论出发 ,采用“呼吸”型裂纹模型 ,考虑了裂纹在轴旋转过程中的开闭情况 ,研究了含裂纹转子的非协调响应 ,如次谐波的产生、周期运动的突跳现象以及拟周期运动 ,并分析了其稳定性。由研究结果可以... 由 Poincaré映射不动点的稳定性理论出发 ,采用“呼吸”型裂纹模型 ,考虑了裂纹在轴旋转过程中的开闭情况 ,研究了含裂纹转子的非协调响应 ,如次谐波的产生、周期运动的突跳现象以及拟周期运动 ,并分析了其稳定性。由研究结果可以看出 ,二次谐波的产生对应于倍周期分叉 ,运动的突跳现象对应于鞍 -结分叉 ,拟周期运动对应于 Naimark- Sacker分叉。 展开更多
关键词 非线性 转子 poincarE映射
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