检索结果-南通市图书馆

Asymmetrical Fault Current Calculation Method and Influencing Factors Analysis of Droop-Controlled Inverters

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第2期10卷 562-573页

作者： Huimin zhao zhikang Shuai Jun Ge An Luo weimin wu z.John Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410006China Electrical Engineering Department Shanghai Maritime UniversityShanghai 201306China Department of Electrical and Computer Engineering Ilinois Institute of TechnologyChicagoIL 60616 USA

Since the fault dynamic of droop-controlled inverter is different from synchronous generators (SGs), protection devices may become invalid, and the fault overcurrent may damage power electronic devices and threaten the safety of the microgrid. Therefore, it is imperative to conduct a comprehensive fault analysis of the inverter to guide the design of protection schemes. However, due to the complexity of droop control strategy, existing literatures have simplified asymmetric fault analysis of droop-controlled inverters to varying degrees. Therefore, accurate fault analysis of a droop-controlled inverter is needed. In this paper, by analyzing the control system, an accurate fault model is established. Based on this, a calculation method for instantaneous asymmetrical fault current is proposed. In addition, the current components and current characteristics are analyzed. It was determined that fault currents are affected by control loops, fault types, fault distance and nonlinear limiters. In particular, the influences of limiters on the fault model, fault current calculation and fault current characteristics were analyzed. Through detailed analysis, it was found that dynamics of the control loop cannot be ignored, the fault type and fault distance determine fault current level, and part of the limiters will totally change the fault current trend. Finally, calculation and experimental results verify the correctness of the proposed method.

关键词： Asymmetrical fault analysis droop control fault current calculation method limiter transient fault characteristics

Intuitive Human-Robot-Environment Interaction with EMG Signals:A Review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1075-1091页

作者： Dezhen Xiong Daohui zhang Yaqi Chu Yiwen zhao Xingang zhao State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016 Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110169 University of Chinese Academy of Sciences Beijing 100049China

A long history has passed since electromyography(EMG)signals have been explored in human-centered robots for intuitive ***,it still has a gap between scientific research and real-life *** studies mainly focused on EMG decoding algorithms,leaving a dynamic relationship between the human,robot,and uncertain environment in real-life scenarios seldomly *** fill this gap,this paper presents a comprehensive review of EMG-based techniques in human-robot-environment interaction(HREI)*** general processing framework is summarized,and three interaction paradigms,including direct control,sensory feedback,and partial autonomous control,are ***-based intention decoding is treated as a module of the proposed *** key issues involving precision,stability,user attention,compliance,and environmental awareness in this field are *** important directions,including EMG decomposition,robust algorithms,HREI dataset,proprioception feedback,reinforcement learning,and embodied intelligence,are proposed to pave the way for future *** the best of what we know,this is the first time that a review of EMG-based methods in the HREI system is *** provides a novel and broader perspective to improve the practicability of current myoelectric interaction systems,in which factors in human-robot interaction,robot-environment interaction,and state perception by human sensations are considered,which has never been done by previous studies.

关键词： robot summarized Robot

Broadband intelligent programmable metasurface with polarization-modulated self-adaptive electromagnetic functionality switching

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2024年第7期12卷 1395-1409页

作者： XIMING LI RUI XU XIAOFENG SUN YUAN zhao zhao YANG GUOHONG DU College of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225China

Programmable metasurfaces have received a great deal of attention due to their ability to dynamically manipulate electromagnetic(EM) waves. Despite the rapid growth, most of the existing metasurfaces require manual control to switch among different functionalities, which poses severe limitations on practical applications. Here, we put forth an intelligent metasurface that has self-adaptive EM functionality switching in broadband without human participation. It is equipped with polarization discrimination antennas(PDAs) and feedback components to automatically adjust functionalities for the different incident polarization information.

关键词： equipped adjust polarization

Remarkable enhancement of gas selectivity on organosilica hybrid membranes using urea-modulated metal-organic framework nanoparticles

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2024年第2期18卷 83-92页

作者： Yayun zhao Dechuan zhao Chunlong Kong Yichao Lin Xuezhen wang Liang Chen Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China Collaboration Innovation Center for Tissue Repair Material Engineering Technology China West Normal UniversityNanchong 637009China

Metal-organic framework/organosilica hybrid membranes on tubular ceramic substrates have shown great potential for the implementation of membrane technology in practical gas separation projects due to their higher permeance compared to commercial ***,the selectivities of the reported membranes are ***,we have incorporated urea-modulated metal-organic frameworks into organosilica membranes to greatly enhance its separation *** urea-modulated metal-organic frameworks exhibit less-defined edges of crystallographic facets and high defect *** can be well-dispersed in the organosilica layer,which substantially suppresses the interfacial defects between metal-organic frameworks and organosilica,which is beneficial for improving the selectivity of membranes for gas *** results have shown that the enhanced ideal selectivity of H_(2)/CH_(4) was 165 and that of CO_(2)/CH_(4) was 43,with H_(2) permeance of about 1.25×10^(−6) mol·m^(−2)·s^(−1)·Pa^(−1) and CO_(2) permeance of 3.27×10^(−7) mol·m^(−2)·s^(−1)·Pa^(−1) at 0.2 MPa and 25℃.In conclusion,the high level of hybrid membranes can be used to separate H_(2)(or CO_(2))from the binary gas mixture H_(2)/CH_(4)(or CO_(2)/CH_(4)),which is important for gas separation in practical ***,the simple and feasible modulation of metal-organic framework is a promising strategy to tune different metal-organic frameworks for membranes according to the actual demands.

关键词： zIF-8 nanocrystals urea organosilica hybrid membrane enhanced separation performance

Gradient-structure-enhanced dielectric energy storage performance of flexible nanocomposites containing controlled preparation of defective TiO_(2) and ferroelectric KNbO_(3) nanosheets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第5期17卷 4079-4088页

作者： Yan wang Lili zhao Ruicong Chen wenhui zhao Dengwei Hu Haoran wang Bin Cui Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education Shaanxi Key Laboratory of Physico–Inorganic Chemistry Xi’an Key Laboratory of Functional Supramolecular Structure and MaterialsCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an 710127China School of Information Science and Technology Northwest UniversityXi’an 710127China Engineering Research Center for Titanium Based Functional Materials and Devices in Universities of Shaanxi Province Faculty of Chemistry and Chemical EngineeringBaoji University of Arts and SciencesBaoji 721013China

Next generation power system needs dielectrics with increased dielectric energy ***,the low energy density of dielectrics limits their ***,an asymmetric trilayered nanocomposite,with a transition layer(TL),an insulation layer(IL),and a polarization layer(PL),is designed based on poly(vinylidene fluoride)-polymethyl methacrylate(PVDF-PMMA)matrix using KNbO_(3)(KN)and TiO_(2)(TO)as the *** morphology and defect control of the two-dimensional nano KN and nano TO fillers are realized via a hydrothermal method to increase the composite breakdown strength(E_(b))and the composite energy density(U_(e)).The asymmetric trilayered structure leads to a gradient electric field distribution,and the KN and TO nanosheets block charges transfer along z *** a result,the development path of the electrical trees is greatly curved,and E_(b) is effectively *** the Ue value of the nanocomposites reaches 17.79 J·cm^(-3) at 523 MV·m^(-1).On the basis,the composite Ue is further improved by defect control in TO *** nanocomposite KN/TO/PVDF-PMMA containing TO with less oxygen vacancy concentration(calcined at oxygen atmosphere)acquires a high Ue of 21.61 J·cm^(-3) at 548 MV·m^(-1).This study provides an idea for improving the energy storage performance by combining the design of the composite dielectric structure and the control of nanofillers’defect and morphology.

关键词： asymmetric trilayered structure two-dimensional energy density oxygen vacancies breakdown strength dielectric

Advances in regional nodal management of early-stage breast cancer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Cancer Research 2024年第2期36卷 215-225页

作者： zhao Bi Yongsheng wang Breast Cancer Center Shandong Cancer Hospital and InstituteShandong First Medical University and Shandong Academy of Medical SciencesJinan 250017China

with the continuous improvement of systemic treatment, reasonable local regional control of early-stage breast cancer can be translated into survival benefits. The optimization of regional nodal management in patients with limited sentinel lymph node(SLN) metastasis needs to be weighed by surgical complications, regional recurrence risk, and lymph node status, as well as other escalating treatment(systemic/radiotherapy) that may result from deescalating surgery. with the effective support and supplementation of systemic therapy and radiotherapy, the management of axillary surgery is developing in a de-escalating trend. The widespread application of neoadjuvant therapy has contributed to optimizing the management of patients with clinically node-negative/imaging nodepositive disease. In clinical practice, it is necessary to consider the residual tumor burden of regional lymph nodes when formulating the optimal irradiation fields in patients with limited positive SLN without axillary lymph node dissection. The combined application of genomic tests and American College of Surgeons Oncology Group z0011/AMAROS criteria could provide patients with a better strategy of dual de-escalation treatment, which includes the de-escalation of both axillary surgery and systemic treatment. In the era of sentinel lymph node biopsy(SLNB), the regional nodal management of breast cancer should adhere to the concept of “updating ideas, making bold assumptions, and carefully seeking proof”, make full use of the benefits of systemic therapy and radiotherapy to reduce the scope of surgery and complications, and expand the “net benefit” of efficacy and quality of life. This review discusses the optimization of regional nodal management in the era of SLNB, in order to provide reference information for clinicians.

关键词： Breast cancer sentinel lymph node biopsy internal mammary lymph node radiotherapy surgery

Bifurcation Analysis Reveals Solution Structures of Phase Field Models

在线全文

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第1期6卷 64-89页

作者： Xinyue Evelyn zhao Long-Qing Chen wenrui Hao Yanxiang zhao Department of Mathematics Vanderbilt UniversityNashvilleTN37212USA Department of Materials Science and Engineering Pennsylvania State UniversityUniversity ParkPA16802USA Department of Mathematics Pennsylvania State UniversityUniversity ParkPA16802USA Department of Mathematics The George Washington UniversityWashingtonDC20052US

The phase field method is playing an increasingly important role in understanding and predicting morphological evolution in materials and biological ***,we develop a new analytical approach based on the bifurcation analysis to explore the mathematical solution structure of phase field *** such solution structures not only is of great mathematical interest but also may provide guidance to experimentally or computationally uncover new morphological evolution phenomena in materials undergoing electronic and structural phase *** elucidate the idea,we apply this analytical approach to three representative phase field equations:the Allen-Cahn equation,the Cahn-Hilliard equation,and the Allen-Cahn-Ohta-Kawasaki *** solution structures of these three phase field equations are also verified numerically by the homotopy continuation method.

关键词： Phase field modeling Bifurcations Multiple solutions

Probing the Kinematic Signatures of Planet Formation in the Gas Disk of MwC 480

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第6期24卷 110-118页

作者： Min zhao Haochuan Yu zhengxiang Li Department of Astronomy Beijing Normal UniversityBeijing 100875China Sub-department of Astrophysics Department of PhysicsUniversity of OxfordOxfordOX13RHUK

The disk around MwC 480 has shown multiple substructures in both dust and gas observations,possibly suggesting ongoing planet formation in *** this paper,we explore the gas kinematics of the MwC 480 disk by analyzing the archival Atacama Large Millimeter/submillimeter Array observations of^(12)CO(J=2-1),^(13)CO(J=2-1),and C^(18)O(J=2-1).By modeling the line-of-sight velocities,inferred from the Doppler shifts of the emission lines,we are able to decompose the three-dimensional(3D)velocity field of the disk into rotational,radial,and vertical *** analysis reveals the presence of large-scale gas flows in the(r,z)***,we identify potential meridional flows across various heights as traced by all three CO isotopologues in the 80–120 au region,possibly associated with ongoing planet formation activities in this ***,we find upward flows near 200 au for all three CO isotopologues,which may point to the presence of disk winds.

关键词： protoplanetary disks planet-disk interactions planet-star interactions

Design and tailoring of patterned znO nanostructures for perovskite light absorption modulation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 855-861页

作者： Haonan Si Xuan zhao Qingliang Liao Yue zhang Academy for Advanced Interdisciplinary Science and Technology Beijing Advanced Innovation Center for Materials Genome EngineeringUniversity of Science and Technology BeijingBeijing 100083China Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of EducationBeijing Key Laboratory for Advanced Energy Materials and TechnologiesSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Lithography is a pivotal micro/nanomanufacturing technique,facilitating performance enhancements in an extensive array of devices,encompassing sensors,transistors,and photovoltaic *** key to creating highly precise,multiscale-distributed patterned structures is the precise control of the lithography ***,high-quality patterned znO nanostructures are constructed by systematically tuning the exposure and development times during *** optimizing these parameters,znO nanorod arrays with line/hole arrangements are successfully *** znO nanostructures with highly controllable morphology and structure possess discrete three-dimensional space structure,enlarged surface area,and improved light capture ability,which achieve highly efficient energy conversion in perovskite solar *** lithography process management for these patterned znO nanostructures provides important guidance for the design and construction of complex nanostructures and devices with excellent performance.

关键词： lithography patterned znO nanorod arrays light absorption perovskite solar cell