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Evaluation of spontaneous combustion tendency of sulfide ore heap based on nonlinear parameters

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Journal of Central South University 2017年第10期24卷 2431-2437页

作者：潘伟吴超李孜军伍智伟杨月平 School of Resources and Safety Engineering Central South University School of Nuclear Resources Engineering University of South China

To explore a new evaluation method for spontaneous combustion tendency of different areas in sulfide ore heap, ore samples from a pyrite mine in China were taken as experimental materials, and the temperature variations of the measuring points of simulated ore heap were measured. Combined with wavelet transform and nonlinear parameters extraction, a new method for spontaneous combustion tendency of different areas in sulfide ore heap based on nonlinear parameters was proposed and its reliability was verified by field test. The results indicate that temperature field evolution of the simulated ore heap presents significant spatial difference during self-heating process. Area with the maximum increasing extent of temperature in sulfide ore heap changes notably with the proceeding of self-heating reaction. Self-heating of sulfide ore heap is a chaotic evolution process, which means that it is feasible to evaluate spontaneous combustion tendency of different areas by nonlinear analysis method. There is a relatively strong correlation between the maximum lyapunov exponent and spontaneous combustion tendency with the correlation coefficient of 0.9792. Furthermore, the sort of the maximum lyapunov exponent is consistent with that of spontaneous combustion tendency. Therefore, spontaneous combustion tendency of different areas in sulfide ore heap can be evaluated by means of the maximum lyapunov exponent method.

关键词： sulfide ore heap spontaneous combustion tendency self-heating process nonlinear parameters maximum lyapunov exponent

Identification of Lagrangian coherent structures in the turbulent boundary layer

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Science China(Physics,Mechanics & Astronomy) 2009年第2期52卷 248-257页

作者： PAN Chong WANG JinJun ZHANG Cao Institute of Fluid Mechanics Beijing University of Aeronautics and AstronauticsBeijing 100083China

Using Finite-Time lyapunov Exponents (FTLE) method, Lagrangian coherent structures (LCSs) in a fully developed flat-plate turbulent boundary layer are successfully identified from a two-dimensional (2D) velocity field obtained by time-resolved 2D PIV measurement. The typical LCSs in the turbulent boundary layer are hairpin-like structures, which are characterized as legs of quasi-streamwise vor- tices extending deep into the near wall region with an inclination angle θ to the wall, and heads of the transverse vortex tube located in the outer region. Statistical analysis on the characteristic shape of typical LCS reveals that the probability density distribution of θ accords well with t-distribution in the near wall region, but presents a bimodal distribution with two peaks in the outer region, corresponding to the hairpin head and the hairpin neck, respectively. Spatial correlation analysis of FTLE field is im- plemented to get the ensemble-averaged inclination angle θ R of typical LCS. θ R first increases and then decreases along the wall-normal direction, similar to that of the mean value of θ. Moreover, the most probable value of θ saturates at y+=100 with the maximum value of about 24°, suggesting that the most likely position where hairpins transit from the neck to the head is located around y+=100. The ensem- ble-averaged convection velocity Uc of typical LCS is finally calculated from temporal-spatial correla- tion analysis of FTLE field. It is found that the wall-normal profile of the convection velocity Uc(y) ac- cords well with the local mean velocity profile U(y) beyond the buffer layer, evidencing that the down- stream convection of hairpins determines the transportation properties of the turbulent boundary layer in the log-region and beyond.

关键词： turbulent boundary layer coherent structures vortex identification scheme finite-time lyapunov exponents hairpin-like vortices

基于lyapunov函数的小天体软着陆障碍规避控制方法

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深空探测学报 2015年第2期2卷 149-167页

作者：胡海静朱圣英崔平远北京理工大学深空探测技术研究所北京100081 飞行器动力学与控制教育部重点实验室北京100081

针对姿轨耦合型探测器控制方法存在工程实现难、计算效率低的问题,提出一种基于lyapunov函数的小天体自主软着陆障碍规避控制方法。首先,建立了小天体着陆过程姿态和轨道的动力学模型;其次,考虑探测器当前的势能与障碍地形对探测器的威... 详细信息

针对姿轨耦合型探测器控制方法存在工程实现难、计算效率低的问题,提出一种基于lyapunov函数的小天体自主软着陆障碍规避控制方法。首先,建立了小天体着陆过程姿态和轨道的动力学模型;其次,考虑探测器当前的势能与障碍地形对探测器的威胁选取lyapunov函数,并根据lyapunov稳定性原理推导了推力器的开关控制逻辑,能够实现到达目标着陆点的同时进行障碍规避,且该过程不需事先设计参考模型。同时,该控制逻辑具有解析形式,能够实现实时障碍规避。仿真结果表明,该方法能够有效实现规避障碍且满足姿态稳定的要求。

关键词：小天体 lyapunov 障碍规避姿轨耦合跟踪控制

Analysis of High Codimensional Bifurcation and Chaos for the Quad Bundle Conductor＇s Galloping

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Chinese Physics Letters 2010年第4期27卷 171-174页

作者：刘富豪张琪昌谭莹 Department of Mechanics School of Mechanical Engineering Tianjin University Tianjin 300072 State of Key Laboratory of Engines Tianjin University Tianjin 300072

iced 的一个 two-degree-of-freedom 模型，电的空铅捆售票员被开发包括地描述观察的不同奔驰行为。由使用歧管、可颠倒的中心线性转变， co-dimension-2 分叉被分析。在这个系统和原来的系统之间的参数的关系被获得分析并且控制空铅 ic... 详细信息

iced 的一个 two-degree-of-freedom 模型，电的空铅捆售票员被开发包括地描述观察的不同奔驰行为。由使用歧管、可颠倒的中心线性转变， co-dimension-2 分叉被分析。在这个系统和原来的系统之间的参数的关系被获得分析并且控制空铅 iced 捆售票员奔驰。空间轨道， lyapunov 代表和 lyapunov 尺寸经由数字模拟被调查介绍混乱的存在的一个严密证明。

关键词：导线舞动分岔分析 lyapunov 余维混沌自由度模型行为观察线性变换

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lyapunov矩阵方程解法

哈尔滨工业大学学报 1983年第1期 55-63页

作者：王子才权太范哈尔滨工业大学自动控制教研室

本文提出了求解lyapunov 矩阵方程的几种方法.这些方法在计算机上实现简单,而且在实际工程中应用它设计次最佳控制系统是比较实用的。

关键词：广义特征向量定义计算机 lyapunov 线性无关矩阵方程初等因子解法

lyapunov和Riccati矩阵代数方程解的一种完整快速的算法

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南京理工大学学报(自然科学版) 1984年第3期 141-151页

作者：王执铨华东工程学院六○五教研室

本文给出了一种由估计系统状态方程的“谱”出发,由计算机辅助解lyapunov方程的算法。在此基础上解出Riccati矩阵代数方程。本文还考虑到若系统状态方程中A阵不稳定时如何选择初始迭代炬阵P0,推导了求P0的公式,并给出了计算它们的程序... 详细信息

本文给出了一种由估计系统状态方程的“谱”出发,由计算机辅助解lyapunov方程的算法。在此基础上解出Riccati矩阵代数方程。本文还考虑到若系统状态方程中A阵不稳定时如何选择初始迭代炬阵P0,推导了求P0的公式,并给出了计算它们的程序框图和算例。

关键词：方程矩阵代数 Riccati lyapunov 算法

Exponential stability and periodic solutions of delayed cellular neural networks

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Science China(Technological Sciences) 2000年第3期43卷 328-336页

作者：曹进德 Department of Applied Mathematics Southeast University Nanjing 210096 China

A set of criteria are presented for the global exponential stability and the existence of periodic solutions of delayed cellular neural networks (DCNNs) by constructing suitable lyapunov function-als, introducing many parameters qij* , rij* , qij, rij∈ R and wi>0 (i, j = 1, 2, …, n) and combining them with the elementary inequality 2ab≤a2 + b2 technique. These criteria have important significance in the design and applications of globally stable DCNNs and periodic oscillatory DCNNs. In addition, the results in literature are extended and improved. Two examples are given to illustrate the theory.

关键词： periodic solution global exponential stability delayed cellular neural networks lyapunov func-tional inequality.

Trajectory planning and tracking control for underactuated unmanned surface vessels

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Journal of Central South University 2014年第2期21卷 540-549页

作者：廖煜雷苏玉民曹建 State Key Laboratory of Autonomous Underwater Vehicle Harbin Engineering University

The trajectory planning and tracking control for an underactuated unmanned surface vessel(USV) were addressed.The reference trajectory was generated by a virtual USV,and the error equation of trajectory tracking for underactuated USV was obtained,which transformed the tracking and stabilization problem of underactuated USV into the stabilization problem of the trajectory tracking error equation.A nonlinear state feedback controller was proposed based on backstepping technique and lyapunov's direct method.By means of lyapunov analysis,it is proved that the proposed controller ensures that the solutions of closed loop system have the ultimate boundedness property.Numerical simulation results are presented to validate the effectiveness and robustness of the proposed controller.

关键词：跟踪控制水面舰艇轨迹规划欠驱动状态反馈控制器 lyapunov 误差方程稳定问题

Second-Order Consensus of Multiple Agents with Coupling Delay

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Communications in Theoretical Physics 2009年第1期51卷 101-109页

作者： SU Hou-Sheng ZHANG Wei Department of Automation Shanghai Jiao Tong University Shanghai 200240 China

在这篇论文，我们与在一般固定指导信息拓扑学下面联合延期为多重代理人调查二种秒顺序一致算法。稳定性分析基于 lyapunov 被执行—Krasovskii 功能的方法。延期依赖者 asymptotical 稳定性状况为推迟的动态网络的秒顺序一致算法以线... 详细信息

在这篇论文，我们与在一般固定指导信息拓扑学下面联合延期为多重代理人调查二种秒顺序一致算法。稳定性分析基于 lyapunov 被执行—Krasovskii 功能的方法。延期依赖者 asymptotical 稳定性状况为推迟的动态网络的秒顺序一致算法以线性矩阵不平等(LMI ) 被导出。延期无关并且延期依赖者 asymptotical 稳定性条件与信息反馈为秒顺序一致算法以 LMI 被导出。

关键词：时滞依赖多Agent 二阶物流管理信息系统耦合 lyapunov 线性矩阵不等式稳定性分析