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GT裁床离线圆弧插补方法
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作者 丁文捷 张早校 王建中 《宁夏工程技术》 CAS 2003年第1期39-42,共4页
论述了在格柏(GT)CNC裁剪机床自动编程模块软件的二次开发设计中,探索以AutoCAD对象AcDbPolyline实现圆弧离线插补的方法.首先分析了传统圆弧插补算法的主要特点,提出在软件中采用弦线逼近弧线,离线、增量式直接函数插补的方法,实现了... 论述了在格柏(GT)CNC裁剪机床自动编程模块软件的二次开发设计中,探索以AutoCAD对象AcDbPolyline实现圆弧离线插补的方法.首先分析了传统圆弧插补算法的主要特点,提出在软件中采用弦线逼近弧线,离线、增量式直接函数插补的方法,实现了平滑插补曲线的设计思想,并简要分析该方法的偏差计算关系.结合AcDbPolyline的圆弧数学描述,给出了与文中插补算法相应的圆弧数学模型间的转化关系式.通过设计插补算法的模型,推导和总结了该方法的程序设计递推关系式;在总结和借鉴终点判断方法的基础上,结合程序设计思想,给出了整圆弧插补的简化方法. 展开更多
关键词 GT裁床 离线圆弧插补方法 平滑性 偏差分析 数控机床 AUTOCAD 增量式直接函数法
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基于标称性能指标的离线鲁棒预测控制器综合 被引量:14
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作者 丁宝苍 杨鹏 《自动化学报》 EI CSCD 北大核心 2006年第2期304-310,共7页
离线鲁棒预测控制综合算法离线确定一个控制律序列,对应一组吸引域,在线根据当前状态的位置选择相应的控制律.该类控制器在线计算量非常小,而可行性和最优性与其它综合算法相比或多或少要差一些.为此,采用标称性能指标而不是“最坏情... 离线鲁棒预测控制综合算法离线确定一个控制律序列,对应一组吸引域,在线根据当前状态的位置选择相应的控制律.该类控制器在线计算量非常小,而可行性和最优性与其它综合算法相比或多或少要差一些.为此,采用标称性能指标而不是“最坏情况”性能指标来改进离线综合算法的可行性和最优性.改进的控制器保持了原有控制器的稳定性以及控制律关于系统状态的连续性.仿真结果说明了采用标称性能指标的优越性. 展开更多
关键词 鲁棒预测控制 离线方法 标称性能指标 稳定性
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动态输出反馈鲁棒模型预测控制离线算法 被引量:7
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作者 平续斌 丁宝苍 《自动化学报》 EI CSCD 北大核心 2013年第6期790-798,共9页
研究具有多包不确定性和有界噪声系统的动态输出反馈鲁棒模型预测控制(Robust model predictive control,RMPC)的离线方法.先前的在线方法中,在估计状态和估计误差集合已知的情况下,在每一采样时刻通过近似最优算法求解控制器参数.本文... 研究具有多包不确定性和有界噪声系统的动态输出反馈鲁棒模型预测控制(Robust model predictive control,RMPC)的离线方法.先前的在线方法中,在估计状态和估计误差集合已知的情况下,在每一采样时刻通过近似最优算法求解控制器参数.本文采用先前的方法计算离线控制器参数和吸引域.首先,选定一系列估计状态,其中,每个估计状态对应同样一组嵌套的估计误差集合.然后,针对每一估计状态和每一估计误差集合的组合,离线计算唯一的控制器参数和对应的吸引域.这些控制器参数和对应的吸引域存储在表中.如果离线确定的吸引域包含实时的扩展状态,则该离线控制器参数是实时可行的.在线时,根据实时估计状态和选取实时估计误差集合,在表中搜索包含实时扩展状态且优化性能指标最小的吸引域所对应的控制器参数.通过连续搅拌釜式反应器控制系统验证了该方法的有效性. 展开更多
关键词 动态输出反馈 模型预测控制 不确定系统 离线方法
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铀矿地质样品的稳定同位素组成测试方法
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作者 张玉鑫 《黑龙江科技信息》 2017年第7期39-39,共1页
主要介绍了铀矿地质样品的稳定同位素的组成测试和方法进行分析,在分析的过程中,需要对样品的用量和种类进行测定,除此之外,还要对N、S、O、C、等同为元素的测试方法进行分析,本文中使用的是连续流方法和离线方法。在使用同位素来进行... 主要介绍了铀矿地质样品的稳定同位素的组成测试和方法进行分析,在分析的过程中,需要对样品的用量和种类进行测定,除此之外,还要对N、S、O、C、等同为元素的测试方法进行分析,本文中使用的是连续流方法和离线方法。在使用同位素来进行岩石、物质来源和矿物成因进行研究的过程中,需要使用没有经过任何改造的岩石或者是矿物。在使用矿物对成岩、与成矿进行研究的过程中,样品必须要选择共生矿物,属于同一个时代的矿物,而且样品必须要新鲜,没有经过任何的改造。主要是对离线方法和在线方法(连续流方法)进行分析,为铀矿地质样品稳定同位素组成测试方法进行分析,为相关的研究提供借鉴。 展开更多
关键词 铀矿地质样品 稳定同位素 离线方法 在线方法
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一种新的绝缘测试方法——回复电压法
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作者 李莉华 《上海电力》 2002年第6期57-57,共1页
关键词 绝缘测试方法 回复电压法 交联聚乙烯电缆 绝缘质量 检测 离线检测方法
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基于光谱共焦探针的Wolter-Ⅰ型X射线显微镜芯轴高精度检测
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作者 薛春安 余俊 +3 位作者 盛鹏峰 王豪杰 王占山 王东方 《光学精密工程》 EI CAS CSCD 北大核心 2024年第13期2004-2016,共13页
Wolter型X射线显微镜具有高分辨率和集光区域,在先进光源和高能激光器中有重要的应用价值。基于镍电镀成形的复制法是制备Wolter型X射线显微镜的有效方法之一,其中,芯轴的表面精度和质量会直接影响X射线成像的性能。高精度检测技术是芯... Wolter型X射线显微镜具有高分辨率和集光区域,在先进光源和高能激光器中有重要的应用价值。基于镍电镀成形的复制法是制备Wolter型X射线显微镜的有效方法之一,其中,芯轴的表面精度和质量会直接影响X射线成像的性能。高精度检测技术是芯轴制备的基础,而传统检测装置难以测量具有圆周回旋对称特征的Wolter型表面轮廓。为了解决Wolter型芯轴检测难和测量精度低的问题,搭建了基于光谱共焦探针的离线检测装置实现芯轴表面中低频轮廓的高精度测量,分析了该装置的各类系统误差和随机误差,并采用双探针与标准镜来校准测试过程,将测试中的温湿度漂移和随机误差的PV值降低至23 nm。最后,开展了该检测装置和CGH干涉检测法的检测对比实验。通过Wolter芯轴表面测试结果比较,两种测试方法的偏差PV值约为60 nm,证明了该检测装置的合理性和检测方法的准确性。 展开更多
关键词 光学测量 Wolter-Ⅰ型X射线显微镜芯轴 离线检测方法 光谱共焦探针 误差分析
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变约束高效预测控制 被引量:5
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作者 高宪文 张立 +1 位作者 王介生 赵娟平 《控制理论与应用》 EI CAS CSCD 北大核心 2011年第6期855-860,共6页
为改善离线鲁棒预测控制算法的最优性引入了变终端约束集的思想,即在原离线方法基础上通过在线优化方法获得构建当前反馈矩阵的凸组合系数,然后再产生当前控制量.与原方法相比增加了在线求解的自由度,改善了系统的最优性.在此基础上,又... 为改善离线鲁棒预测控制算法的最优性引入了变终端约束集的思想,即在原离线方法基础上通过在线优化方法获得构建当前反馈矩阵的凸组合系数,然后再产生当前控制量.与原方法相比增加了在线求解的自由度,改善了系统的最优性.在此基础上,又提出了变约束预测控制(VC–MPC)算法,根据状态所处的不同稳定椭圆域确定其对应的控制约束,在取得相同优化性能情况下较恒定约束算法明显节省了计算时间.仿真实例验证了所提方法的有效性. 展开更多
关键词 鲁棒预测控制 离线方法 终端约束集 变约束 线性矩阵不等式
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改进的扰动LPV系统输出反馈预测控制
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作者 王平 赵敏 《电子科技》 2023年第1期81-87,共7页
针对一类带有有界状态干扰的多胞描述LPV系统,文中提出了一种鲁棒预测控制改进方法,并设计了保证系统渐近稳定的输出反馈控制器。为抵消有界状态干扰,该控制器考虑无扰动LPV系统,基于离线状态观测器,采用线性矩阵不等式求解预测控制无... 针对一类带有有界状态干扰的多胞描述LPV系统,文中提出了一种鲁棒预测控制改进方法,并设计了保证系统渐近稳定的输出反馈控制器。为抵消有界状态干扰,该控制器考虑无扰动LPV系统,基于离线状态观测器,采用线性矩阵不等式求解预测控制无穷时域最小-最大优化问题。随后利用离线状态观测器获得扰动LPV系统与无扰动LPV系统状态的估计值之差,以确定保性能的反馈增益,从而得到使扰动LPV系统渐近稳定的最优偏移量,并将其与无扰动系统控制律组合作为最优控制律施加于实际系统。实验结果表明,运用改进的鲁棒预测控制方法能获得较好地控制性能,同时提高了系统的稳定性和解决优化问题的效率,仿真试验也验证了该算法的有效性。 展开更多
关键词 LPV系统 有界干扰 输出反馈 LMI 渐近稳定性 MPC 离线方法 鲁棒预测控制
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Interaction Between Line Soliton and Algebraic Soliton for Asymmetric Nizhnik-Novikov-Veselov Equation 被引量:1
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作者 RUAN Hang-Yu LI Zhi-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第6期1547-1552,共6页
Starting from the variable separation approach, the algebraic soliton solution and the solution describing the interaction between line soliton and algebraic soliton are obtained by selecting appropriate seed solution... Starting from the variable separation approach, the algebraic soliton solution and the solution describing the interaction between line soliton and algebraic soliton are obtained by selecting appropriate seed solution for (2+1)-dimensional ANNV equation. The behaviors of interactions are discussed in detail both analytically and graphically. It is shown that there are two kinds of singular interactions between line soliton and algebraic soliton: 1) the resonant interaction where the algebraic soliton propagates together with the line soliton and persists infinitely; 2) the extremely repulsive interaction where the algebraic soliton affects the motion of the line soliton infinitely apart. 展开更多
关键词 variable separation approach the interaction between line soliton and algebraic soliton (2+1)-dimensional ANNV equation
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Standing,Periodic and Solitary Waves in (1+1)-Dimensional Caudry-Dodd-Gibbon-Sawada-Kortera System
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作者 郑春龙 强继业 王绍华 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第12期1054-1058,共5页
In the paper, the variable separation approach, homoclinic test technique and bilinear method are successfullyextended to a (1+1)-dimensional Caudry-Dodd-Gibbon-Sawada-Kortera (CDGSK) system, respectively.Basedon the ... In the paper, the variable separation approach, homoclinic test technique and bilinear method are successfullyextended to a (1+1)-dimensional Caudry-Dodd-Gibbon-Sawada-Kortera (CDGSK) system, respectively.Basedon the derived exact solutions, some significant types of localized excitations such as standing waves, periodic waves,solitary waves are simultaneously derived from the (1+1)-dimensional Caudry-Dodd-Gibbon-Sawada-Kortera systemby entrancing appropriate parameters. 展开更多
关键词 CDGSK type model variable separation approach homoclinic test technique standing wave periodic wave solitary wave
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Particle stratification and penetration of a linear vibrating screen by the discrete element method 被引量:7
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作者 Xiao Jianzhang Tong Xin 《International Journal of Mining Science and Technology》 SCIE EI 2012年第3期357-362,共6页
A simulation of stratification and penetration was performed over a range of structural parameters that included screen width, aperture size, inclination angle, and wire diameter. The discrete element method (DEM) w... A simulation of stratification and penetration was performed over a range of structural parameters that included screen width, aperture size, inclination angle, and wire diameter. The discrete element method (DEM) was used for the simulations. The terms stratification and penetration are defined and the change in fine panicle concentration is discussed. Mathematical models relating fine particle ratio to time are established using the least squares method. The effect of structural parameters on fine panicle ratio is analyzed. Stratification and penetration rate are discussed by considering the time derivative of the fine panicle ratio. The conclusions are: an increase in inclination or wire diameter has a positive effect on par- ticle stratifying; The optimal screen width is 40 mm for panicle stratification; The inclination angle has a negative effect on the penetration; The effect of wire diameter and screen width on the penetration rate is negligible. 展开更多
关键词 Fine particle ratioStratificationPenetrationStructural parameter
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Separation of chalcopyrite and pyrite from a copper tailing by ammonium humate 被引量:10
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作者 Cuicui Lü Yongliang Wang +5 位作者 Peng Qian Ya Liu Guoyan Fu Jian Ding Shufeng Ye Yuanfa Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第9期1814-1821,共8页
Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method,... Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method, Xray diffraction and scanning electron microscope-energy dispersive spectrum. It turned out that chalcopyrite(Cu) and pyrite(S) were the main recoverable minerals in the tailing. In order to separate chalcopyrite from pyrite in low pulp pH, ammonium humate(AH) was singled out as the effective regulator. The depression mechanism of AH on the flotation of pyrite was proved by FTIR spectrum and XPS spectrum, demonstrating that there was a chemical adsorption between AH and pyrite. By Response Surface Methodology(RSM), the interaction between AH, pulp pH and iso-butyl ethionine(Z200) was discussed. It was illustrated that the optimal dosage of AH was 1678 g·t^(-1) involving both the recovery of Cu and S. The point prediction by RSM and the closed-circuit flotation displayed that the qualified Cu concentrate and S concentrate could be obtained from the copper tailing.The study indicated that AH was a promising pyrite depressor in the low pulp pH from copper tailings. 展开更多
关键词 Copper tailings Ammonium humate DEPRESSION Response Surface Methodology
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An improved method of mitochondrial DNA isolation for XL-PCR
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作者 时多 朱克军 +4 位作者 王学敏 汪振诚 郑建明 缪明永 焦炳华 《Journal of Medical Colleges of PLA(China)》 CAS 2006年第2期82-85,共4页
Objective: To obtain high quality of mitochondrial DNA (mtDNA) and carry out extra-long PCR (XL-PCR). Methods: Mitochondria were isolated by differential centrifugation, and membranes were disrupted using 10%SDS... Objective: To obtain high quality of mitochondrial DNA (mtDNA) and carry out extra-long PCR (XL-PCR). Methods: Mitochondria were isolated by differential centrifugation, and membranes were disrupted using 10%SDS (pH 7.0). mtDNA was then extracted using phenol and chloroform. Resuits: The mtDNA obtained by using our improved method can be used as effective template for XL-PCR, and total mtDNA (16 kb) can be amplified easily. Conclusion: Our improved method is effective in preparing high quality of mtDNA, which can be used as template for XL-PCR. 展开更多
关键词 mitochondria DNA ISOLATION extra-long PCR DELETION
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Solutions and Conditional Lie-Backlund Symmetries of Quasi-linear Diffusion-Reaction Equations 被引量:1
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作者 ZUO Su-Li QU Chang-Zheng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第1期6-12,共7页
New classes of exact solutions of the quasi-linear diffusion-reaction equations are obtained by seeking for the high-order conditional Lie-Baeklund symmetries of the considered equations. The method used here extends ... New classes of exact solutions of the quasi-linear diffusion-reaction equations are obtained by seeking for the high-order conditional Lie-Baeklund symmetries of the considered equations. The method used here extends the approaches of derivative-dependent functional separation of variables and the invariant subspace. Behavior to some solutions such as blow-up and quenching is also described. 展开更多
关键词 conditional Lie-Backlund symmetry exact solution quasi-linear diffusion-reaction equation
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Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas
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作者 SHI Jun XIAO Sha-li +2 位作者 WANG Hong-jian TANG Chang-huan LIU Shen-ye 《Optoelectronics Letters》 EI 2008年第4期299-301,共3页
In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the... In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal (200) (2d = 0.4027 nm) is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line(w), the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line(x), the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines(y), the 1 s2p ^3S^1-1 s^2 ^1S0 forbidden line(z) in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line(q) in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution(λ/△ 2) is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy. 展开更多
关键词 弯晶分光计 X射线 激光等离子体 测量方法
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Mixing matrix estimation of underdetermined blind source separation based on the linear aggregation characteristic of observation signals
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作者 温江涛 Zhao Qianyun Sun Jiedi 《High Technology Letters》 EI CAS 2016年第1期82-89,共8页
Under the underdetermined blind sources separation(UBSS) circumstance,it is difficult to estimate the mixing matrix with high-precision because of unknown sparsity of signals.The mixing matrix estimation is proposed b... Under the underdetermined blind sources separation(UBSS) circumstance,it is difficult to estimate the mixing matrix with high-precision because of unknown sparsity of signals.The mixing matrix estimation is proposed based on linear aggregation degree of signal scatter plot without knowing sparsity,and the linear aggregation degree evaluation of observed signals is presented which obeys generalized Gaussian distribution(GGD).Both the GGD shape parameter and the signals' correlation features affect the observation signals sparsity and further affected the directionality of time-frequency scatter plot.So a new mixing matrix estimation method is proposed for different sparsity degrees,which especially focuses on unclear directionality of scatter plot and weak linear aggregation degree.Firstly,the direction of coefficient scatter plot by time-frequency transform is improved and then the single source coefficients in the case of weak linear clustering is processed finally the improved K-means clustering is applied to achieve the estimation of mixing matrix.The proposed algorithm reduces the requirements of signals sparsity and independence,and the mixing matrix can be estimated with high accuracy.The simulation results show the feasibility and effectiveness of the algorithm. 展开更多
关键词 underdetermined blind source separation (UBSS) sparse component analysis(SCA) mixing matrix estimation generalized Gaussian distribution (GGD) linear aggregation
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Integrable discretization of soliton equations via bilinear method and Backlund transformation
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作者 ZHANG Ying Nan CHANG Xiang Ke +2 位作者 HU Juan HU Xing Biao TAM Hon-Wah 《Science China Mathematics》 SCIE CSCD 2015年第2期279-296,共18页
We present a systematic procedure to derive discrete analogues of integrable PDEs via Hirota’s bilinear method.This approach is mainly based on the compatibility between an integrable system and its B¨acklund tr... We present a systematic procedure to derive discrete analogues of integrable PDEs via Hirota’s bilinear method.This approach is mainly based on the compatibility between an integrable system and its B¨acklund transformation.We apply this procedure to several equations,including the extended Korteweg-deVries(Kd V)equation,the extended Kadomtsev-Petviashvili(KP)equation,the extended Boussinesq equation,the extended Sawada-Kotera(SK)equation and the extended Ito equation,and obtain their associated semidiscrete analogues.In the continuum limit,these differential-difference systems converge to their corresponding smooth equations.For these new integrable systems,their B¨acklund transformations and Lax pairs are derived. 展开更多
关键词 integrable discretization bilinear method Backlund transformation
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A NEWTON MULTIGRID METHOD FOR QUASILINEAR PARABOLIC EQUATIONS
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作者 YU Xijun 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2005年第4期429-438,共10页
A combination of the classical Newton Method and the multigrid method, i.e., a Newton multigrid method is given for solving quasilinear parabolic equations discretized by finite elements. The convergence of the algori... A combination of the classical Newton Method and the multigrid method, i.e., a Newton multigrid method is given for solving quasilinear parabolic equations discretized by finite elements. The convergence of the algorithm is obtained for only one step Newton iteration per level. The asymptotically computational cost for quasilinear parabolic problems is O(NNk) similar to multigrid method for linear parabolic problems. 展开更多
关键词 Quasilinear parabolic equation finite element discretization Newton multi-grid method convergence analysis.
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