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A methodology for laser tool setters calibration and its precise mathematical model

Chinese Journal of Aeronautics 2024年第7期37卷 564-581页

作者： Tao fang Zixi fang Ze Zhong CHEN Zhiyong CHANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Gina Cody School of Engineering and Computer Science Concordia UniversityMontrealQuebec H3G 1M8Canada Changsha Optimum CNC Corporation Changsha 410221China Institute for Aero-engine Smart Assembly of Shaanxi Province Xi’an 710072China

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine *** tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and *** a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before ***,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring *** address this issue,this study proposes a novel calibration ***,the calibration mechanism of the laser beam axis is *** on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is ***,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during ***,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate ***,the accuracy of the calibration method is verified through simulation experiments and calibration *** method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool *** research significantly improves the efficient production performance of smart machine tools.

关键词： On-machine tool setting Smart machine tools Mathematical model Calibration method Laser tool sette

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Triangle-free Graphs with Three Positive Eigenvalues

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Algebra Colloquium 2024年第3期31卷 525-540页

作者： fang Duan School of Mathematical Sciences Xinjiang Normal UniversityUrumqi 830017China

A graph G is called triangle-free if G does not contain any triangle as its induced *** G_(n)be the set of triangle-free graphs of order n each of which has three positive *** this paper,we find 20 specific graphs in G_(n),each of which has nullity no more than 2,and we show that in terms of three graph transformations all the other graphs of G_(n)can be constructed from these 20 specific ***,we completely characterize the triangle-free graphs with exactly three positive eigenvalues.

关键词： positive(negative)inertia index nullity triangle-free graph

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Superior compound coatings prepared by low-temperature vanadium-nitrocarburizing duplex treatment

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Rare Metals 2024年第4期43卷 1828-1835页

作者： Gen Jin fang-fang Xu Xun-Xun Hu Yue Xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as well as the growth kinetics of the layer was also *** the duplex treatment,the wear and corrosion resistances of steel surface were significantly *** was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Growth kinetics

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Control of Virtual Synchronous Generator for Frequency Regulation Using a Coordinated Self-adaptive Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 175-184页

作者： Hongwei fang Zhiwei Yu School of Electrical and Information Engineering and Key Laboratory of Tianjin Electric Power System Simulation and Control Tianjin UniversityTianjin 300072China

Power inverter adopting virtual synchronous generator(VSG)control can provide inertia support for distributed generation ***,it cannot take into account the dynamic regulation characteristics of ***,when the system encounters a sudden change in load or disturbance,the dynamic process of frequency regulation will be greatly *** view of this issue,an improved VSG control strategy based on a coordinated self-adaptive(CSA)method is *** time domain analysis method is used to study the influences of virtual inertia and damping parameter perturbation on the system steady and dynamic ***,in order to make the control strategy suitable for large load changes and suppress frequency variations beyond the limit,the secondary frequency modulation is introduced into the control *** the coordinated adaptive control of virtual inertia,virtual damping and frequency modulation,the dynamic performance of vSG frequency regulation can be obviously *** and experiment results have verified the effectiveness of the proposed CSA control strategy.

关键词： Coordinated self-adaptive method frequency regulation time domain analysis virtual synchronous generator

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Microbe-induced gene silencing explores interspecies RNAi and opens up possibilities of crop protection

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Science China(Life Sciences) 2024年第3期67卷 626-628页

作者： Rongxiang fang State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of Sciencesand National Plant Gene Research CenterBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

In most eukaryotes, small RNA(sRNA)-mediated RNA silencing(or RNA interference, RNAi) is an evolutionarily conserved mechanism that regulates gene expression in a sequence-specific ***, s RNAs are produced by the RNase III enzymes Dicers and then incorporated into Argonaute(AGO) proteins to regulate gene expression by mRNA degradation.

关键词： protection conserved manner

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A disk I/O optimized system for concurrent graph processing jobs

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Frontiers of Computer Science 2024年第3期18卷 13-29页

作者： Xianghao XU fang WANG Hong JIANG Yongli CHENG Dan FENG Peng fang School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Department of Computer Science&Engineering University of Texas at ArlingtonArlingtonTX 76019USA College of Computer and Data Science Fuzhou UniversityFuzhou 350108China Zhejiang Lab Hangzhou 311121China

In order to analyze and process the large graphs with high cost efficiency,researchers have developed a number of out-of-core graph processing systems in recent years based on just one commodity *** the other hand,with the rapidly growing need of analyzing graphs in the real-world,graph processing systems have to efficiently handle massive concurrent graph processing(CGP)***,due to the inherent design for single graph processing job,existing out-of-core graph processing systems usually incur unnecessary data accesses and severe competition of I/O bandwidth when handling the CGP *** this paper,we propose GraphCP,a disk I/O optimized out-of-core graph processing system that efficiently supports the processing of CGP *** proposes a benefit-aware sharing execution model to share the I/O access and processing of graph data among the CGP jobs and adaptively schedule the graph data loading based on the states of vertices,which efficiently overcomes above challenges faced by existing out-of-core graph processing ***,GraphCP adopts a dependency-based future-vertex updating model so as to reduce disk I/Os in the future *** addition,GraphCP organizes the graph data with a Source-Sorted Sub-Block graph representation for better processing capacity and I/O access *** evaluation results show that GraphCP is 20.5×and 8.9×faster than two out-of-core graph processing systems GridGraph and GraphZ,and 3.5×and 1.7×faster than two state-of-art concurrent graph processing systems Seraph and GraphSO.

关键词： graph processing disk I/O concurrent jobs

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Molecular Conformational Isomerization:An Efficient Way to Design Novel Emitters with Dual-Thermally Activated Delayed Fluorescence Characteristics and Their Optoelectronic and Bioimaging Applications

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CCS Chemistry 2024年第4期6卷 912-922页

作者： Yi-Zhong Shi Ya-fang Xiao Hao Wu Shao-Li Zhang Xiao-Chun Fan Ye Tian Chang-Qing Ye Kai Wang Jia Yu Chun-sing Lee Xiao-Hong Zhang School of Materials Science and Engineering Suzhou University of Science and TechnologySuzhou 215009 Institute of Functional Nano and Soft Materials(FUNSOM) Joint International Research Laboratory of Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhou 215123Jiangsu Center of Super-Diamond and Advanced Films(COSDAF) Department of ChemistryCity University of Hong KongHong Kong SAR School of Biomedical Engineering The Second Affiliated HospitalGuangzhou Medical UniversityGuangzhou 510260 Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Soochow UniversitySuzhou 215123Jiangsu Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySuzhou 215123Jiangsu

single-molecule luminophores with dual-thermally activated delayed fluorescence(TADF)properties are receiving increasing ***,how to achieve these goals requires more in-depth ***,we demonstrate a novel example emitter,10-(5-(2-(pyridin-3-yl)-[4,5′-bipyrimidin]-6-yl)pyridin-2-yl)-10Hphenoxazine(PmPy-PXZ),enabling dual-TADF properties due to its key feature of conformational *** a pyridine bridge can greatly reduce the steric hindrance and facilitate dual-stable conformations in the ground state,where the quasi-axial(QA)forms ***,unlike previously reported TADF molecules with dual confirmations,both theoretical and experimental measurements show that not only the quasi-equatorial(QE)forms but also the QA forms exhibit distinct TADF characteristics,which can be attributed to an additional higher reverse intersystem crossing *** is the first time that dual-TADF properties of single molecules have been achieved based on conformational *** applications in“self-doping”organic light-emitting diode and biomedical imaging have further been *** these results show the good potential of such dual-band TADF emitters based on molecular conformational isomerization.

关键词： dual-thermally activated delayed fluorescence conformational isomerization organic light-emitting diode biomedical imaging self-doping

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Planning an adaptive reuse development of underutilized urban underground infrastructures:A case study of Qingdao,China

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Underground Space 2024年第1期14卷 18-33页

作者： Yong-Kang Qiao fang-Le Peng Yun-Hao Dong Chun-fang Lu Research Center for Underground Space&Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

Urban underground infrastructures(UUIs)are a vital component of built capital for urban ***,many cities are now home to a multitude of disused or underutilized UUIs,not least aged purpose-built underground facilities,causing a waste of valuable underground space resource *** the process of urban renewal,adaptive reuse can be an attractive solution to breathe new life into underutilized UUIs,while addressing some of the modern problems of the built environment by an economically feasible ***,there is a prevalent absence in the current literature of the overarching planning and decision-making approaches for an adaptive reuse development of underutilized *** the intention of addressing this shortfall,this paper first lays out development strategies,then sets the generic patterns for adaptive reuse of disused or underutilized *** the city of Qingdao,China as a case study,detailed planning and decision-making approaches with the aid of multi-source data and spatial analysis tools are *** is anticipated that the findings of this research will assist the adaptive reuse development of UUIs in providing theoretical guidance and empirical evidence,thereby enhancing the role of urban underground space use in contributing to urban revitalization and urban sustainability.

关键词： Urban underground infrastructures Underutilized Adaptive reuse Planning Urban renewal

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A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： Wei WEI Feng GUAN Xin fang College of Intelligent Science National University of Defense TechnologyChangsha410073China Naval Research Academy Beijing100161China

A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave *** consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and *** bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are *** experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate

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Non-dimensional analysis on blast wave propagation in foam concrete:Minimum thickness to avoid stress enhancement

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Defence Technology（防务技术） 2024年第6期36卷 30-46页

作者： Ya Yang Xiangzhen Kong Qin fang State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007JiangsuChina

Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau ***,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast *** investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov *** difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress *** difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are *** particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is ***,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering.

关键词： Foam concrete Blast wave propagation Non-dimensional analysis Stress enhancement

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