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Feasibility of a novel beamforming algorithm via retrieving spatial harmonics 被引量:2
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作者 NOROLAHI Jafar AZMI Paeiz NASIRIAN Mahdi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第1期38-46,共9页
This paper introduces an algorithm for beamforming systems by the aid of multidimensional harmonic retrieval(MHR).This algorithm resolves problems,removes limitations of sampling and provides a more robust beamformer.... This paper introduces an algorithm for beamforming systems by the aid of multidimensional harmonic retrieval(MHR).This algorithm resolves problems,removes limitations of sampling and provides a more robust beamformer.A new sample space is created that can be used for estimating weights of a new beamforming called spatial-harmonics retrieval beamformer(SHRB).Simulation results show that SHRB has a better performance,accuracy,and applicability and more powerful eigenvalues than conventional beamformers.A simple mathematical proof is provided.By changing the number of harmonics,as a degree of freedom that is missing in conventional beamformers,SHRB can achieve more optimal outputs without increasing the number of spatial or temporal samples.We will demonstrate that SHRB offers an improvement of 4 dB in signal to noise ratio(SNR) in bit error rate(BER) of 10~(-4) over conventional beamformers.In the case of direction of arrival(DOA) estimation,SHRB can estimate the DOA of the desired signal with an SNR of-25 dB,when conventional methods cannot have acceptable response. 展开更多
关键词 multi-input-multi-output(MIMO) BEAMFORMING spatial and temporal signal processing multidimensional harmonic retrieval(MHR) space-time signal processing array signal processing
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Optimizing the generation of second harmonic optical vortices from nonlinear photonic crystals
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作者 LIU Shiqiang ZHANG Xinyu +4 位作者 CHEN Yan LI Shifeng ZHAO Gang ZHU Shining HU Xiaopeng 《物理学进展》 北大核心 2025年第4期161-168,共8页
The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex... The generation of optical vortices from nonlinear photonic crystals(NPCs)with spatially modulated second-order nonlinearity offers a promising approach to extend the working wavelength and topological charge of vortex beams for various applications.In this work,the second harmonic(SH)optical vortex beams generated from nonlinear fork gratings under Gaussian beam illumination are numerically investigated.The far-field intensity and phase distributions,as well as the orbital angular momentum(OAM)spectra of the SH beams,are analyzed for different structural topological charges and diffraction orders.Results reveal that higher-order diffraction and larger structural topological charges lead to angular interference patterns and non-uniform intensity distributions,deviating from the standard vortex profile.To optimize the SH vortex quality,the effects of the fundamental wave beam waist,crystal thickness,and grating duty cycle are explored.It is shown that increasing the beam waist can effectively suppress diffraction order interference and improve the beam’s quality.This study provides theoretical guidance for enhancing the performance of nonlinear optical devices based on NPCs. 展开更多
关键词 optical vortex nonlinear photonic crystal second harmonic generation orbital angular momentum
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A high output power 340 GHz balanced frequency doubler designed based on linear optimization method
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作者 LIU Zhi-Cheng ZHOU Jing-Tao +5 位作者 MENG Jin WEI Hao-Miao YANG Cheng-Yue SU Yong-Bo JIN Zhi JIA Rui 《红外与毫米波学报》 北大核心 2025年第2期184-191,共8页
In this paper,a linear optimization method(LOM)for the design of terahertz circuits is presented,aimed at enhancing the simulation efficacy and reducing the time of the circuit design workflow.This method enables the ... In this paper,a linear optimization method(LOM)for the design of terahertz circuits is presented,aimed at enhancing the simulation efficacy and reducing the time of the circuit design workflow.This method enables the rapid determination of optimal embedding impedance for diodes across a specific bandwidth to achieve maximum efficiency through harmonic balance simulations.By optimizing the linear matching circuit with the optimal embedding impedance,the method effectively segregates the simulation of the linear segments from the nonlinear segments in the frequency multiplier circuit,substantially improving the speed of simulations.The design of on-chip linear matching circuits adopts a modular circuit design strategy,incorporating fixed load resistors to simplify the matching challenge.Utilizing this approach,a 340 GHz frequency doubler was developed and measured.The results demonstrate that,across a bandwidth of 330 GHz to 342 GHz,the efficiency of the doubler remains above 10%,with an input power ranging from 98 mW to 141mW and an output power exceeding 13 mW.Notably,at an input power of 141 mW,a peak output power of 21.8 mW was achieved at 334 GHz,corresponding to an efficiency of 15.8%. 展开更多
关键词 linear optimization method(LOM) three-dimensional electromagnetic model(3D-EM) Harmonic impedance optimization Schottky planar diode Terahertz frequency doubler
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A(NH_(2)SO_(3))(A=Li,Na):Two ultraviolet transparent sulfamates exhibiting second harmonic generation response
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作者 MO Cuiwu ZHANG Gangmin +2 位作者 WU Chao HUANG Zhipeng ZHANG Chi 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第7期1387-1396,共10页
Two alkali-metal sulfamates nonlinear optical(NLO)crystals,Li(NH_(2)SO_(3))and Na(NH_(2)SO_(3)),have been obtained through the facile evaporation method.Li(NH_(2)SO_(3))crystallizes in the polar space group Pca2_(1)(N... Two alkali-metal sulfamates nonlinear optical(NLO)crystals,Li(NH_(2)SO_(3))and Na(NH_(2)SO_(3)),have been obtained through the facile evaporation method.Li(NH_(2)SO_(3))crystallizes in the polar space group Pca2_(1)(No.29).The structure of Li(NH_(2)SO_(3))can be described as a 3D network formed by[LiO_(4)]^(7-)polyhedral connecting with NH_(2)SO_(3)^(-)tetrahedra through corner-sharing.Na(NH_(2)SO_(3))crystallizes in the polar space group P2_(1)2_(1)2_(1)(No.19).The structure of Na(NH_(2)SO_(3))can be described as a 3D network formed by distorted[NaO_(6)]^(11-)octahedral connecting with NH_(2)SO_(3)^(-)tetrahedra through corner-sharing.The UV-Vis-near-infrared spectra demonstrate that Li(NH_(2)SO_(3))and Na(NH_(2)SO_(3))possessed large optical band gaps of 5.25 and 4.81 eV,respectively.Powder second-harmonic generation(SHG)measurements demonstrate that the SHG intensity of Li(NH_(2)SO_(3))and Na(NH_(2)SO_(3))were 0.32 times and 0.31 times that of KH_(2)PO_(4),respectively.First-principles calculations confirm the nonlinear optical performance mainly derived from the synergistic effect of amino sulfonate anions and alkali metal oxide anionic polyhedra.CCDC:2339109,Li(NH_(2)SO_(3));2339110,Na(NH_(2)SO_(3)). 展开更多
关键词 UV nonlinear optical materials bandgap second harmonic generation first-principle calculation
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Harmonic Impedance Modeling and Oscillation Analysis of Modular Multilevel Converter
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作者 Wang Yuhong Chen Wensheng +2 位作者 Gao Shilin Liao Jianquan Cheng Yangfan 《系统仿真学报》 CAS CSCD 北大核心 2024年第12期2755-2770,共16页
To facilitate rapid analysis of the oscillation stability mechanism in modular multilevel converter-based high voltage direct current(MMC-HVDC)systems and streamline the simulation process for determining MMC impedanc... To facilitate rapid analysis of the oscillation stability mechanism in modular multilevel converter-based high voltage direct current(MMC-HVDC)systems and streamline the simulation process for determining MMC impedance characteristics,a simplified mathematical simulation model for MMC closed-loop impedance is developed using the harmonic state space method.This model considers various control strategies and includes both AC-side and DC-side impedance models.By applying a Nyquist criterion-based impedance analysis method,the stability mechanisms on the AC and DC sides of the MMC are examined.In addition,a data-driven oscillation stability analysis method is also proposed,leveraging a global sensitivity algorithm based on fast model results to identify key parameters influencing MMC oscillation stability.Based on sensitivity analysis results,a parameter adjustment strategy for oscillation suppression is proposed.The simulation results from the MATLAB/Simulinkbased MMC model validate the effectiveness of the proposed method. 展开更多
关键词 modular multilevel converter impedance modeling harmonic state space global sensitivity impedance analysis
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基于模糊支配的高维多目标进化算法MFEA 被引量:16
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作者 毕晓君 张永建 陈春雨 《电子学报》 EI CAS CSCD 北大核心 2014年第8期1653-1659,共7页
为提高高维复杂多目标优化算法的收敛性和解集分布性,提出一种基于模糊支配的高维多目标进化算法MFEA.在第二代Pareto支配类高维多目标进化算法模型基础上,利用模糊理论对模型中的环境选择进行改进,提出基于模糊隶属度的支配关系,并结合... 为提高高维复杂多目标优化算法的收敛性和解集分布性,提出一种基于模糊支配的高维多目标进化算法MFEA.在第二代Pareto支配类高维多目标进化算法模型基础上,利用模糊理论对模型中的环境选择进行改进,提出基于模糊隶属度的支配关系,并结合Harmonic、k邻域法和小生境技术对其中的拥挤密度估计方法进行改进,最后根据高维多目标的特点并结合模糊理论α-截集的思想提出了新的环境选择策略.将该算法与目前性能最好的5种多目标进化算法在标准测试函数集上进行对比试验,结果表明本文算法与其他算法相比具有明显的优势,不仅提高了算法的收敛性能,而且保证了Pareto最优解的均匀分布性. 展开更多
关键词 高维多目标优化 模糊隶属度 模糊支配 Harmonic平均距离 α-截集
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基于双种群的约束多目标优化算法 被引量:10
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作者 毕晓君 张磊 肖婧 《计算机研究与发展》 EI CSCD 北大核心 2015年第12期2813-2823,共11页
为提高约束多目标优化算法的分布性和收敛性,提出一种基于双种群的约束多目标优化算法.首先,改进的Harmonic距离一方面去除了Pareto等级较差个体和较远个体的影响,从而改善可行解集的分布性;另一方面有效减少了计算量,可以提高算法效率... 为提高约束多目标优化算法的分布性和收敛性,提出一种基于双种群的约束多目标优化算法.首先,改进的Harmonic距离一方面去除了Pareto等级较差个体和较远个体的影响,从而改善可行解集的分布性;另一方面有效减少了计算量,可以提高算法效率.其次,新的不可行解集更新方式与可行解集紧密联系,保留目标函数值和约束违反度同时较优的个体,将有助于产生更优可行解,同时提高了种群的多样性和搜索效率.最后,新的变异策略充分利用最优可行解和优秀不可行解的优良信息来引导种群进化,很好地兼顾了探索和开发能力,进而平衡全局搜索和局部搜索.将提出算法与其他3种优秀的约束多目标进化算法在CTP测试集上进行对比实验,结果表明提出算法相比其他算法具有一定的优势,不仅提升了算法的收敛性能,而且保证了Pareto解集良好的分布性. 展开更多
关键词 约束多目标优化 Harmonic距离 不可行解集 变异策略 分布性 收敛性
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模糊K-Harmonic Means聚类算法 被引量:6
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作者 赵恒 杨万海 张高煜 《西安电子科技大学学报》 EI CAS CSCD 北大核心 2005年第4期603-606,638,共5页
对K-HarmonicMeans算法进行扩展,考虑到数据点对不同类的隶属关系,将模糊的概念应用到聚类中,提出了模糊K-HarmonicMeans算法,推导出聚类中心和模糊隶属度的迭代公式.在中心迭代聚类算法统一框架的基础上,推导出FKHM算法聚类中心的条件... 对K-HarmonicMeans算法进行扩展,考虑到数据点对不同类的隶属关系,将模糊的概念应用到聚类中,提出了模糊K-HarmonicMeans算法,推导出聚类中心和模糊隶属度的迭代公式.在中心迭代聚类算法统一框架的基础上,推导出FKHM算法聚类中心的条件概率表达式以及在迭代过程中的数据加权函数表达式.最后,用Folkes&Mallows指标对聚类结果进行评价.实验表明,模糊K-HarmonicMeans(KHM)算法在聚类对于初值不敏感的同时提高了聚类结果的精确度,达到较好的聚类效果. 展开更多
关键词 模糊K—Harmonic Means聚类 聚类中心 条件概率 Folkes & Mallows指标
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合著者贡献率的国际文献回顾 被引量:5
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作者 王红 王全红 《现代情报》 CSSCI 北大核心 2016年第5期63-70,共8页
本文对合著者贡献率的国际文献进行了回顾,分析了修正Harmonic算法,CCA分配法,夏普里值法,Ab-index以及NBA算法等作者贡献分配率算法的优缺点。结果表明:修正Harmonic算法在评价作者贡献时仅仅区分第一作者,年长作者和其它作者,评价算... 本文对合著者贡献率的国际文献进行了回顾,分析了修正Harmonic算法,CCA分配法,夏普里值法,Ab-index以及NBA算法等作者贡献分配率算法的优缺点。结果表明:修正Harmonic算法在评价作者贡献时仅仅区分第一作者,年长作者和其它作者,评价算法相对简单。CCA分配法通过常数K,调整了合著者之间的贡献分配,CCA算法合著者贡献率取值在Fractional和Harmonic算法范围之间。夏普里值法通过界定具体的边际贡献细节确定某一作者在合著中的边际贡献,但计算过程复杂。Ab-index明确区分了第一作者,通讯作者和其它作者的贡献;提出了适合各年龄层次的作者区分度方法,易于操作。NBA算法贡献率分配指数随着学科不同而取不同的值。 展开更多
关键词 合著者 贡献率 文献回顾 Harmonic算法 CCA分配法 夏普里值法 Ab-index
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照料史、隔代照料对我国中老年人健康的影响——基于Harmonized CHARLS的研究 被引量:34
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作者 陈英姿 孙伟 《人口学刊》 CSSCI 北大核心 2019年第5期45-56,共12页
现代社会家庭规模以小型化和核心化为主,但不论农村还是城市,孩子的生养教化等功能仍由家庭承担,很多祖辈依然承担着照料孙辈的任务,隔代照料在现代社会仍发挥重要作用。隔代照料对照料者的健康会产生一定的影响,这种影响因“居住安排... 现代社会家庭规模以小型化和核心化为主,但不论农村还是城市,孩子的生养教化等功能仍由家庭承担,很多祖辈依然承担着照料孙辈的任务,隔代照料在现代社会仍发挥重要作用。隔代照料对照料者的健康会产生一定的影响,这种影响因“居住安排”而异,同时照料状态的转变,即照料角色的获取或退出、持续或中断等不同“照料史”的变化对照料者的健康也有影响。本文采用南加州大学经济与社会研究中心提供的Harmonized CHARLS 2013-2015年追踪数据,选取45-80岁的中老年人为研究对象,以虚弱指数表征健康结果,运用滞后变量回归模型,从“居住安排”和“照料史”两个维度研究隔代照料行为对照料者健康的影响。研究发现:与子女同住且提供隔代照料对老年人的健康有改善作用;照料史的动态变化影响照料者健康,新进入照料角色对照料者的健康有改善作用;在照料孙辈的同时,祖辈出于利他主义动机为成年子女提供经济支持能显著改善其健康状况;男性在提供隔代照料过程中更容易经历健康的亏损,尤其是单身的男性照料者;以上结论仅适用于70岁以下的照料者,对于70岁及以上的老年群体,长期提供隔代照料会加重健康负担。 展开更多
关键词 隔代照料 照料史 虚弱指数 Harmonized CHARLS
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可调度的小波网格变形 被引量:1
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作者 路梅 赵向军 叶澄清 《计算机工程与应用》 CSCD 北大核心 2006年第6期75-79,87,共6页
三维网格模型的Morphing是计算机动画研究的重要内容,利用频谱工具控制变形成份出现的次序是对变形路径进行控制的有效方法之一。但在三维网格模型上无法直接进行频谱分析,使得该技术一直无法在网格模型的Morphing中发挥作用。论文在数... 三维网格模型的Morphing是计算机动画研究的重要内容,利用频谱工具控制变形成份出现的次序是对变形路径进行控制的有效方法之一。但在三维网格模型上无法直接进行频谱分析,使得该技术一直无法在网格模型的Morphing中发挥作用。论文在数字几何处理框架的基础上,提出了利用小波分析进行可控网格变形的新方法。针对变形研究和数字几何处理中的关键问题——特征点对齐和采样,分别提出了基于Harmonic映射的参数化网格warping的特征对齐方法以及新型的自适应采样方法。实验表明,该方法稳定可靠,计算量适中,变形结果更为丰富。 展开更多
关键词 数字几何处理 三维Morphing 特征对齐 Harmonic映射
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基于超平面投影的高维多目标进化算法 被引量:7
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作者 毕晓君 王朝 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2018年第7期1284-1293,共10页
针对高维多目标优化问题(MaOPs),为了更好地在收敛性和分布性之间保持平衡,提出基于超平面投影的高维多目标进化算法(HPEA).通过归一化技术构造单位超平面,将种群个体垂直投影到单位超平面上,消除收敛程度的影响;通过改进的Harmonic平... 针对高维多目标优化问题(MaOPs),为了更好地在收敛性和分布性之间保持平衡,提出基于超平面投影的高维多目标进化算法(HPEA).通过归一化技术构造单位超平面,将种群个体垂直投影到单位超平面上,消除收敛程度的影响;通过改进的Harmonic平均距离,评估单位超平面上投影点的拥挤密度;结合收敛信息构造λ-distance,更好地平衡解集收敛性与分布性.为了检验所提算法的性能,将之用于求解3~10个目标的9类标准测试函数,与目前国内外具有代表性的5种高维多目标进化算法对比可知,该算法相对于其他算法具有优势,能够在提高算法收敛性的同时,保证解集的分布性. 展开更多
关键词 高维多目标优化 超平面投影 Harmonic平均距离 收敛信息 λ-distance
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A global harmony search algorithm for finding optimal capacitor location and size in distribution networks 被引量:2
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作者 Reza Sirjani Melkamu Gamene Bade 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1748-1761,共14页
Shunt capacitors are broadly applied in distribution systems to scale down power losses, improve voltage profile and boost system capacity. The amount of capacitors added and location of deployment in the system highl... Shunt capacitors are broadly applied in distribution systems to scale down power losses, improve voltage profile and boost system capacity. The amount of capacitors added and location of deployment in the system highly determine the advantage of compensation. A novel global harmony search(GHS) algorithm in parallel with the backward/ forward sweep power flow technique and radial harmonic power flow was used to investigate the optimal placement and sizing of capacitors in radial distribution networks for minimizing power loss and total cost by taking account load unbalancing, mutual coupling and harmonics. The optimal capacitor placement outcomes show that the GHS algorithm can reduce total power losses up to 60 k W and leads to more than 18% of cost saving. The results also demonstrate that the GHS algorithm is more effective in minimization of power loss and total costs compared with genetic algorithm(GA), particle swarm optimization(PSO) and harmony search(HS) algorithm. Moreover, the proposed algorithm converges within 800 iterations and is faster in terms of computational time and gives better performance in finding optimal capacitor location and size compared with other optimization techniques. 展开更多
关键词 optimal capacitor placement harmonics unbalancing harmony search algorithm
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中国新会计准则国际协调效果研究——基于会计信息可比性的视角 被引量:6
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作者 吕晓燕 张滕滕 《山东大学学报(哲学社会科学版)》 CSSCI 北大核心 2010年第4期118-123,共6页
基于会计信息可比性的视角,运用2005年至2008年AH股公司双重披露的数据来分析和检验中国新会计准则国际协调的效果。研究表明,双重披露的净资产、净利润、经营现金净流量无显著性差异,双重披露的差异呈现阶段性显著缩小的趋势,说明新会... 基于会计信息可比性的视角,运用2005年至2008年AH股公司双重披露的数据来分析和检验中国新会计准则国际协调的效果。研究表明,双重披露的净资产、净利润、经营现金净流量无显著性差异,双重披露的差异呈现阶段性显著缩小的趋势,说明新会计准则与国际财务报告准则实现了实质上的协调,但是三个指标并没有同步实现了国际协调。 展开更多
关键词 中国 会计准则国际协调 效果研究 会计信息 可比性 视角 China International HARMONIZATION ACCOUNTING Standards New ACCOUNTING Information 双重披露 新会计准则 国际财务报告准则 经营现金净流量 无显著性差异 同步实现 现阶段 净资产 净利润
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Coordination of multiple grid-connected inverters for harmonic compensation
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作者 郭晓瑞 郭吉丰 王剑 《Journal of Central South University》 SCIE EI CAS 2014年第8期3126-3132,共7页
For multiple grid-connected inverters with active filter function,it makes sense to regulate every unit to output maximum active power from photovoltaic arrays,as well as eliminate the harmonic due to the non-linear l... For multiple grid-connected inverters with active filter function,it makes sense to regulate every unit to output maximum active power from photovoltaic arrays,as well as eliminate the harmonic due to the non-linear loads connected to the electric networks.Naturally,a centralized control coordination strategy was proposed for the purpose of high facility utilization,good harmonic compensation ability and unwanted overcompensation condition.Based on a vector decoupling control scheme and generalized instantaneous reactive power theory,the solution was to allocate the harmonic eliminating task for every inverter according to the instantaneous power margin of each.The grid current always keeps sinusoidal in spite of non-linear load change and output active power change for any inverter.The simulation results validate the efficacy of the proposed coordination strategy. 展开更多
关键词 active filter harmonics grid-connected inverter decoupling control COORDINATION
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Decoupling control and zero dynamics stabilization for shunt hybrid active power filter
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作者 鲁伟 李春文 《Journal of Central South University》 SCIE EI CAS 2014年第5期1946-1955,共10页
An inverse system method based optimal control strategy was proposed for the shunt hybrid active power filter (SHAPF) to enhance its harmonic elimination performance. Based on the inverse system method, the d-axis a... An inverse system method based optimal control strategy was proposed for the shunt hybrid active power filter (SHAPF) to enhance its harmonic elimination performance. Based on the inverse system method, the d-axis and q-axis current dynamics of the SHAPF system were decoupled and linearized into two pseudolinear subsystems. Then, an optimal feedback controUer was designed for the pseudolinear system, and the stability condition of the resulting zero dynamics was presented. Under the control strategy, the current dynamics can asymptotically converge to their reference states and the zero dynamics can be bounded. Simulation results show that the proposed control strategy is robust against load variations and system parameter mismatches, its steady-state performance is better than that of the traditional linear control strategy. 展开更多
关键词 harmonics hybrid active power filter inverse system method optimal control zero dynamics
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A new measuring method for maximal length, width and thickness dimensions of coarse aggregates
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作者 段跃华 张肖宁 吴传海 《Journal of Central South University》 SCIE EI CAS 2011年第6期2150-2156,共7页
In order to establish a new method for measuring the dimensions of coarse aggregates, five different-size flat and elongated (F&E) coarse aggregates were glued into two specimens by epoxy resin, respectively, and ... In order to establish a new method for measuring the dimensions of coarse aggregates, five different-size flat and elongated (F&E) coarse aggregates were glued into two specimens by epoxy resin, respectively, and slice images were obtained by X-ray CT, then the aggregates were extracted by the fuzzy c-means clustering algorithm. Attributions of the particle on different cross-sections were determined by the ‘overlap area method’. And unified three-dimensional Cartesian coordinate system was established based on continuous slice images. The coefficient values of spherical harmonics descriptor representing particles surface profile were gained, then each scanned particle was represented by 60×120 discrete points conformably with spherical harmonics descriptor. The chord length and direction angles were determined by the calculation. With the major axis (L) and orthogonal axis (W and T), the calculated results were compared with those measured by caliper. It is concluded that the new L, W, and T dimension measuring method is able to take the place of the present manual measurement. 展开更多
关键词 coarse aggregate flat and elongated (F&E) aggregate X-ray CT digital image processing fuzzy c-means clustering overlap area method spherical harmonics
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Theoretical analysis of adaptive harmonic window and its application in frequency extraction of vibration signal 被引量:10
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作者 LI Shun-ming WANG Jin-rui LI Xiang-lian 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期241-250,共10页
The goal of this paper is to find an excellent adaptive window function for extracting the weak vibration signal and high frequency vibration signal under strong noise.The relationship between windowing transform andf... The goal of this paper is to find an excellent adaptive window function for extracting the weak vibration signal and high frequency vibration signal under strong noise.The relationship between windowing transform andfiltering is analyzed first in the paper.The advantage of adjustable time-frequency window of wavelet transform is introduced.Secondly the relationship between harmonic wavelet and multiple analytic band-pass filter is analyzed.The coherence of the multiple analytic band-pass filter and harmonic wavelet base function is discussed,and the characteristic that multiple analytic band-pass filter included in the harmonic wavelet transform is founded.Thirdly,by extending the harmonic wavelet transform,the concept of the adaptive harmonic window and its theoretical equation without decomposition are put forward in this paper.Then comparing with the Hanning window,the good performance of restraining side-lobe leakage possessed by adaptive harmonic window is shown,and the adaptive characteristics of window width changing and analytical center moving of the adaptive harmonic window are presented.Finally,the proposed adaptive harmonic window is applied to weak signal extraction and high frequency orbit extraction of high speed rotor under strong noise,and the satisfactory results are achieved.The application results show that the adaptive harmonic window function can be successfully applied to the actual engineering signal processing. 展开更多
关键词 window function Fourier transform filter harmonic wavelet ADAPTIVE vibration signal extraction
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Harmonic Current′s Coupling Effect on the Main Motion of Temper Mill Set 被引量:6
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作者 HE Jian-jun YU Shou-yi ZHONG Jue 《Journal of Central South University》 SCIE EI CAS 2000年第3期162-164,共3页
The paper probes into a probable condition that causes temper mill chatter from aspect of electromechanical coupling of complex electromechanical system, and mainly studies the effect of temper mill electrical driving... The paper probes into a probable condition that causes temper mill chatter from aspect of electromechanical coupling of complex electromechanical system, and mainly studies the effect of temper mill electrical driving system harmonic current on the main motion of temper mill set. Aiming at the electrical driving system of CM04 temper mill, the effect of harmonic current is analyzed and evaluated according to different load. Combining the features of CM04 temper mill′s structure and its working state, the paper discusses in every detail how the harmonic current in main circuit, which can be regarded as a disturbance via feedback control circuit , influences main motion of temper mill set. 展开更多
关键词 ELECTROMECHANICAL coupling TEMPER MILL HARMONIC current ROLLING MILL chatter
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Optimization and experimental research on a new-type short cylindrical cup-shaped harmonic reducer 被引量:10
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作者 高海波 庄红超 +3 位作者 李志刚 邓宗全 丁亮 刘振 《Journal of Central South University》 SCIE EI CAS 2012年第7期1869-1882,共14页
In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model betwee... In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model between a flexspline and a wave generator. The validity of the parameterized equivalent contact model was verified by comparing the results of the analytic value of the contact model and the value calculated by the theoretical formula. The curvilinear trend of stress was obtained by changing the structural parameter of the flexspline. Based on the curvilinear trend of stress,multi-objective optimizations of key structural parameters were achieved. Flexspline,wave generator,and circular spline of a new 32-type short cylindrical cup-shaped harmonic reducer were designed and manufactured. A performance test bench to carry out tests on the harmonic reducer was designed. Contrast experiments were implemented to determine the efficiency of the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer under different conditions. The experimental results reveal that there is approximately equality in terms of efficiency between the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer. The volume of the flexspline of the new 32-type short cylindrical cup-shaped harmonic reducer is reduced by approximately 30% through multi-objective optimization. When the new 32-type short cylindrical cup-shaped harmonic reducer is used on the wheel of a rover prototype,the mass of the wheel hub is decreased by 0.42 kg. Test analysis of wheel motion verifies that the new 32-type short cylindrical cup-shaped harmonic reducer can meet the requirements regarding bearing capacity and efficiency. 展开更多
关键词 harmonic drive FLEXSPLINE structural parameter multi-objective optimization
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