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A Hybrid Signal Processing Method Combining Mathematical Morphology and Walsh Theory for Power Quality Disturbance Detection and Classification

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 584-592页

作者： zhi ding Tianyao Ji Mengshi Li Q.H.Wu School of Electric Power Engineering South China University of Technology(SCUT)Guangzhou 510641China

In this paper, a novel signal processing method combining mathematical morphology (MM) and Walsh theory is proposed, which uses Walsh functions to control the structuring element (SE) and MM operators. Based on the Walsh-MM method, a scheme for power quality disturbances detection and classification is developed, which involves three steps: denoising, feature extraction and morphological clustering. First, various evolution rules of Walsh function are used to generate groups of SEs for the multiscale Walsh-ordered morphological operation, so the original signal can be denoised. Next, the fundamental wave of the denoised signal is suppressed by Hadamard matrix;thus, disturbances can be extracted. Finally, the Walsh power spectrum of the waveform extracted in the previous step is calculated, and the parameters of which are taken by morphological clustering to classify the disturbances. Simulation results reveal the proposed scheme can effectively detect and classify disturbances, and the Walsh-MM method is less affected by noise and only involves simple calculation, which has a potential to be implemented in hardware and more suitable for real-time application.

关键词： Hadamard matrix mathematical morphology morphological clustering power quality disturbance Walsh theory

Numerical Study of Two Opposing Weak Polyelectrolyte Brushes by the Self-consistent Field Theory

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Chinese Journal of Polymer Science 2024年第11期 1668-1678页

作者： Bei-Ning Wang Huan-da ding zhi-Kuan Chen Chao-Hui Tong Department of Physics Ningbo University Ningbo Institute of Northwestern Polytechnical University

The self-consistent field theory(SCFT) was employed to numerically study the interaction and interpenetration between two opposing weak polyelectrolyte(PE) brushes formed by grafting weak PE chains onto the surfaces of two long and parallel columns with rectangularshaped cross-section immersed in a salty aqueous solution. The dependences of the brush heights and the average degree of ionization on various system parameters were also investigated. When the brush separation is relatively large compared with the unperturbed brush height, the degree of interpenetration between the two opposing PE brushes was found to increase with increasing grafting density and bulk degree of ionization. The degree of interpenetration also increases with the bulk salt concentration in the osmotic brush regime. Numerical results further revealed that, at a brush separation comparable to the unperturbed brush height, the degree of interpenetration does not increase further with increasing bulk degree of ionization, bulk salt concentration in the osmotic regime and grafting density. The saturation of the degree of interpenetration with these system parameters indicates that the grafted PE chains in the gap between the two columns retract and tilt in order to reduce the unfavorable electrostatic and steric repulsions between the two opposing PE brushes. Based on salt ion concentrations at the midpoint between the two opposing brushes, a quantitative criterion in terms of the unperturbed brush height and Debye screening length was established to determine the threshold value of the brush separation beyond which they are truly independent from each other.

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基于旋转多普勒效应的自旋目标转速估计方法

物理学报 2023年第17期72卷 196-208页

作者：印必还何姿丁大志南京理工大学电子工程与光电技术学院南京210094

旋转多普勒效应是携带轨道角动量的涡旋电磁波用于旋转目标探测时的一种重要现象.相比于传统平面波,旋转多普勒效应使得涡旋电磁波可以沿目标旋转轴方向探测到目标的自旋运动.然而,对于特定结构的自旋目标,利用整数阶轨道角动量波束进... 详细信息

旋转多普勒效应是携带轨道角动量的涡旋电磁波用于旋转目标探测时的一种重要现象.相比于传统平面波,旋转多普勒效应使得涡旋电磁波可以沿目标旋转轴方向探测到目标的自旋运动.然而,对于特定结构的自旋目标,利用整数阶轨道角动量波束进行探测仍然存在盲区.为了拓展基于旋转多普勒效应的探测方案的适用范围,本文基于时频分析方法,研究了在分数阶轨道角动量波束正入射和斜入射时自旋目标的转速估计方法.首先基于理想散射点模型,推导了其在整数阶和分数阶轨道角动量波束正入射和斜入射时的回波模型,以及理论时频曲线.其次,以三维实际目标为例,基于矩量法和短时傅里叶变换方法,得到目标在分数阶轨道角动量波束入射时的回波及其时频图,并从时频图中提取时频脊及其波动周期,以此估计目标自旋速度.结果证明,分数阶轨道角动量波束无论在正入射还是斜入射情况下均可有效地估计自旋目标的旋转速度,并且能够克服整数阶轨道角动量波束的探测盲区,在探测目标自旋运动时具有更广泛的适用性.

关键词：旋转多普勒效应分数阶轨道角动量斜入射时频分析

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State of the art in movement around a remote point:a review of remote center of motion in robotics

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Frontiers of Mechanical Engineering 2024年第2期19卷 1-28页

作者： Wuxiang ZHANG zhi WANG Ke MA Fei LIU Pengzhi CHENG Xilun ding School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Ningbo Institute of Technology Beihang UniversityNingbo 315832China Intelligent Aerospace Manufacturing Engineering Technology Co. Ltd.Beijing 100191China

The concept of remote center of motion(RCM)is pivotal in a myriad of robotic applications,encompa-ssing areas such as medical robotics,orientation devices,and exoskeletal *** efficacy of RCM technology is a determining factor in the success of these robotic *** paper offers an exhaustive review of RCM technologies,elaborating on their various methodologies and practical *** delves into the unique characteristics of RCM across different degrees of freedom(DOFs),aiming to distill their fundamental *** addition,this paper categorizes RCM approaches into two primary classifications:design based and control *** are further organized according to their respective DOFs,providing a concise summary of their core *** upon the understanding of RCM’s versatile capabilities,this paper then transitions to an in-depth exploration of its applications across diverse robotic *** this review,we critically analyze the existing research challenges and issues that are inherently present in both RCM methodologies and their *** discussion is intended to serve as a guiding framework for future research endeavors and practical deployments in related areas.

关键词： remote center of motion mechanism robotics medical robot orientation device exoskeleton

Transcriptome-based analysis of key signaling pathways affecting the formation of primordial germ cell in chickens

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Journal of Integrative Agriculture 2024年第5期23卷 1644-1657页

作者： Ying ding Qiong zhi Qisheng Zuo Kai Jin Wei Han Bichun Li Key Laboratory of Animal Genetics Breeding and Molecular Design of Jiangsu ProvinceCollege of Animal Science and TechnologyYangzhou UniversityYangzhou 225009China Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China Yangzhou UniversityYangzhou225009China Poultry Research Institute Chinese Academy of Agricultural Sciences/Jiangsu Institute of Poultry ScienceYangzhou 225009China

Bone morphogenetic protein 4(BMP4)can induce the formation of chicken primordial germ cells(PGCs)in vitro;however,its regulatory mechanism in poultry remains *** study aimed to use RNA-seq to analyze PGCs in chicken embryos and iPGCs induced by BMP4 in vitro,clarify the internal regulatory factors of PGCs,analyze the mechanism of the formation of PGCs,and lay a theoretical foundation for the further optimization of PGCs induction *** stem cells(ESCs),PGCs and iPGCs induced by BMP4 in vitro were *** transcriptional maps of the three cell types were studied using *** results showed 6,142 genes differentially expressed between PGCs and iPGCs,of which 2,728 were upregulated in iPGCs and 3,414 were downregulated in *** to that in ESCs,BMP4 was significantly upregulated in PGCs and *** results showed that both the TGF-βand Wnt signaling pathways were activated during the formation of PGCs in vitro and in vivo,and the activation was more significant during iPGCs induced by *** expression of Nodal,an inhibitory factor of TGF-βsignaling,was significantly decreased in PGCs and iPGCs,but was not expressed in iPGCs,which further supports our ***,the Lysosome and PI3K-AKT signaling pathways were significantly enriched in PGCs and iPGCs,***,transmission electron microscopy(TEM)results showed that the number of autolysosomes was significantly higher after the addition of BMP4,which is consistent with the KEGG ***,the number of PGCs was significantly reduced after ATG14 was interfered in vivo and in *** conclusion,this study screened out the key signaling pathways during the formation of PGCs,aiming to provide help for enriching the mechanism network regulating PGCs formation in chicken and laying a theoretical foundation for further improving the efficiency of inducing PGCs in vitro.

关键词： RNA-seq BMP4 PGCs ATG14 chicken

A 3D-printed microhemispherical shell resonator with electrostatic tuning for a Coriolis vibratory gyroscope

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Microsystems & Nanoengineering 2024年第2期10卷 25-35页

作者： Baoyin Hou Ye Zhu Chaofan He Weidong Wang zhi ding Wen He Yong He Lufeng Che College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou310027China Center for Microelectronics Shaoxing InstituteZhejiang UniversityShaoxing312035China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310058China School of Mechanical Engineering Zhejiang UniversityHangzhou310058China

The emergence of microhemispherical resonant gyroscopes,which integrate the advantages of exceptional stability and long lifetime with miniaturization,has afforded new possibilities for the development of whole-angle ***,existing methods used for manufacturing microhemispherical resonant gyroscopes based on MEMS technology face the primary drawback of intricate and costly ***,we report the design,fabrication,and characterization of the first 3D-printable microhemispherical shell resonator for a Coriolis vibrating *** remarkably achieve fabrication in just two steps bypassing the dozen or so steps required in traditional *** utilizing the intricate shaping capability and ultrahigh precision offered by projection microstereolithography,we fabricate 3D high-aspect-ratio resonant structures and controllable capacitive air gaps,both of which are extremely difficult to obtain via MEMS *** addition,the resonance frequency of the fabricated resonators can be tuned by electrostatic forces,and the fabricated resonators exhibit a higher quality factor in air than do typical MEMS microhemispherical *** work demonstrates the feasibility of rapidly batch-manufacturing microhemispherical shell resonators,paving the way for the development of microhemispherical resonator gyroscopes for portable inertial ***,this particular design concept could be further applied to increase uptake of resonator tools in the MEMS community.

关键词： resonator tuning electrostatic

Analytical solution for tunnelling-induced response of an overlying pipeline considering gap formation

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Underground Space 2024年第2期15卷 298-311页

作者： Cungang Lin Junjie Zheng Yiwen Ye Farrokh Nadim Zhongqiang Liu Chenyang Zhao Yu Chen zhi ding Guangdong Research Center for Underground Space Exploitation Technology School of Civil EngineeringSun Yat-sen UniversityGuangzhou 510275China Guangdong Key Laboratory of Marine Civil Engineering School of Civil EngineeringSun Yat-sen UniversityGuangzhou 510275China State Key Laboratory for Tunnel Engineering Ministry of EducationGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China School of Civil Engineering Wuhan UniversityWuhan 430072China Guangdong Road and Bridge Construction Development Co. Ltd.Guangzhou 510660China Norwegian Geotechnical Institute Oslo 0806Norway Key Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of Zhejiang Province Hangzhou 310015China

Soil-pipeline separation due to tunnelling has been certainly substantiated in previous model ***,this phenomenon has seldom been considered in current analytical *** study formulates a tensionless Winkler solution that could make allowance for gap formation in soil-pipeline interaction *** solution is validated by comparisons with existing experimental measurements and two recognized analytical ***,its advantage over an existing Winkler solution is *** parametric studies reveal that the effects of gap formation on the response of a pipeline rely largely on the tunnel volume loss and the pipeline’s bending stiffness and burial *** general,a pipeline’s bending moments and subgrade reaction forces are more susceptible than its deflections to the gap formation.

关键词： Soil-pipeline interaction Tunnelling Tensionless Winkler model Ground settlement Analytical solution Gap formation

Microstructures and mechanical properties of a commercial Mg-Al-Zn-Mn alloy with various hot-extrusion processes

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Rare Metals 2024年第3期43卷 1329-1336页

作者： He Ma Fan-zhi Meng Qiang Yang Ze-Feng Xie Yuan-ding Huang Xin Qiu State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Materials Science and Engineering Changchun University of Science and TechnologyChangchun130022China MagIC-Magnesium Innovation Center Helmholtz-Zentrum Geesthacht21502GeesthachtGermany Engineering Research Center of Optoelectronic Functional Materials Ministry of EducationChangchun University of Science and TechnologyChangchun130022China

Mg-Al-Zn-Mn(AZ)system alloys have become widely used due to their good castability,excellent formability and outstanding corrosion resistance[1-6].However,their strength is still much lower than that of traditional Mg... 详细信息

关键词： alloys alloy corrosion

Synthesis of Organic-Inorganic Hybrid Aluminum Hypophosphite Microspheres Flame Retardant and Its Flame Retardant Research on Thermoplastic Polyurethane

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 221-233页

作者：刘生鹏 XU zhi ZHANG Xinyuan WEI Huan XIONG Yun ding Yigang HUANG Wenbo 许莉莉 Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education Key Laboratory for Green Chemical Process of Ministry of EducationSchool of Chemical Engineering and PharmacyWuhan Institute of TechnologyWuhan 430205China Hubei Three Gorges Laboratory Yichang 443007China School of Technology Materials Science and Engineering Wuhan Institute of TechnologyWuhan 430205China

Aluminum hypophosphite microspheres(AHP) were synthesized by hydrothermal method using NaH2PO2·H2O and AlCl3·6H2O as raw materials, and then the AHP microspheres were polymerized by surface polymerization of micro-nanospheres with cyclic cross-linked poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol)(PZS). A new organic-inorganic poly(phosphonitrile)-modified aluminum hypophosphite microspheres(PZS-AHP) were synthesized by encapsulation and applied to flame retardant thermoplastic polyurethane(TPU). The microstructure and chemical composition of the PZS-AHP microsphere were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray spectroscopy. The thermal stability of PZS-AHP microsphere was explored with thermogravimetric analysis. Thermogravimetric data indicate that the PZS-AHP microspheres have excellent thermal stability. The thermal and flame-retarding properties of the TPU composites were evaluated by thermogravimetric(TG), limited oxygen index tests(LOI), and cone calorimeter test(CCT). The TPU composite achieved vertical burning(UL-94) V-0 grade and LOI value reached 29.2% when 10 wt% PZS-AHP was incorporated. Compared with those of pure TPU, the peak heat release rate(pHRR) and total heat release(THR) of TPU/10%PZS-AHP decreased by 82.2% and 42.5%, respectively. The results of CCT indicated that PZS-AHP microsphere could improve the flame retardancy of TPU composites.

关键词： polyphosphazene thermoplastic polyurethane flame retardancy aluminum hypophosphite surface polymerization