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Velocity Constraints Based Approach for Online Trajectory Planning of High‑Speed Parallel Robots

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 98-109页

作者： di yang Fugui Xie Xinjun Liu State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Lab of Precision/Ultra‑Precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China

High-speed parallel robots have been extensively utilized in the light ***,the influence of the nonlinear dynamic characteristics of high-speed parallel robots on system’s dynamic response and stable operation cannot be ignored during the high-speed reciprocating ***,trajectory planning is essential for efficiency and stability from pick-and-place(PAP)*** paper presents a method for planning the equal-height pick-and-place trajectory considering velocity constraints to improve the PAP efficiency and stability of high-speed parallel *** velocity constraints in the start-and-end points can reduce vibration from picking and placing,making the trajectory more suitable to complex beltline *** on velocity constraints,trajectory optimization includes trajectory smoothness and joint torque to optimize cycle time is carried *** paper proposes an online trajectory optimization *** using back propagation(BP)neural networks,the solution is simplified and can be solved in *** and experiments were carried out on the SR4 parallel *** results show that the proposed method improves the efficiency,smoothness,and stability of the *** paper proposes an online trajectory planning method which is velocity constraints based and can improve the efficiency and stability of high-speed parallel *** work of this research is conducive to finely applying high-speed parallel robots.

关键词： Trajectory planning High-speed parallel robot Velocity constraints BP neural network

Recent advances in phenazine-linked porous catalysts toward photo/electrocatalytic applications and mechanism

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Green Energy & Environment 2024年第10期9卷 1518-1549页

作者： yang Liu Yu Zhang Zhao-di yang Liqiang Jing Heilongjiang Provincial Key Laboratory of CO_(2) Resource Utilization and Energy Catalytic Materials School of Material Science and Chemical EngineeringHarbin University of Science and TechnologyHarbinHeilongjiang150080China Institute of Process Engineering Chinese Academy of Sciences100080BeijingChina Key Laboratory of Functional Inorganic Materials Chemistry(Ministry of Education) School of Chemistry and Materials ScienceInternational Joint Research Center for Catalytic TechnologyHeilongjiang UniversityHarbin150080China

In recent years,porous organic catalysts have been developed and become research hotspots in photo/electrocatalysis due to their inherent pores,high specific surface area,chemical and thermal stability,and diverse functional building ***-linked organic catalysts,exhibited excellent conjugation,electrical conductivity,chemical,and thermal stability,could bring in N atoms with specific numbers and positions to regulate electron levels,anchor metals,and absorb near-infrared light,which expands solar energy *** advantages of the phenazine-linked catalysts attracted our group and numerous researchers to conduct experimental and computational work on photo/electrocatalytic applications and *** review summarizes the recent significant research progress,synthesis methods,photo/electrocatalytic performance,and applications of relative phenazine-linked ***,the photo/electrocatalytic mechanism was systematized and summarized by combining experiments and density functional theory calculations simultaneously.

关键词： Phenazine-linked porous catalysts Photo/electrocatalytic applications Catalytic mechanism

Mapping regional forest management units:a road-based framework in Southeastern Coastal Plain and Piedmont

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Forest Ecosystems 2021年第2期8卷 223-239页

作者： di yang Chiung-Shiuan Fu Wyoming Geographic Information Science Center University of Wyoming1000E.University AveLaramieWyoming 82071USA Department of Geography University of Florida330 Newell DrGainesvilleFlorida 32611USA

Management practices are one of the most important factors affecting forest structure and *** in southern United States manage forests using appropriately sized areas,to meet management objectives that include economic return,sustainability,and esthetic *** networks spatially designate the socioenvironmental elements for the forests,which represented and aggregated as forest management *** networks are widely used for managing forests by setting logging roads and *** propose that common types of forest management are practiced in road-delineated units that can be determined by remote sensing satellite imagery coupled with crowd-sourced road network *** sensors do not always capture roadcaused canopy openings,so it is difficult to delineate ecologically relevant units based only on satellite *** integrating citizen-based road networks with the National Land Cover Database,we mapped road-delineated management units across the regional landscape and analyzed the size frequency distribution of management *** found the road-delineated units smaller than 0.5 ha comprised 64%of the number of units,but only0.98%of the total forest *** also applied a statistical similarity test(Warren's Index)to access the equivalency of road-delineated units with forest disturbances by simulating a serious of neutral *** outputs showed that the whole southeastern *** the probability of road-delineated unit of 0.44 and production forests overlapped significantly with disturbance areas with an average probability of 0.50.

关键词： Forest management unit Warren's index Neutral landscape OpenStreetMap Road ecology

Combination of structural reliability and interval analysis

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Acta Mechanica Sinica 2008年第1期24卷 61-67页

作者： Zhiping Qiu di yang Isaac Elishakoff Institute of Solid Mechanics Beihang University Beijing 100083 China Department of Mechanical Engineering Florida Atlantic UniversityBoca Raton FL 33431-0991 USA

In engineering applications, probabilistic reliability theory appears to be presently the most important method, however, in many cases precise probabilistic reliability theory cannot be considered as adequate and credible model of the real state of actual affairs. In this paper, we developed a hybrid of probabilistic and non-probabilistic reliability theory, which describes the structural uncertain parameters as interval variables when statistical data are found insufficient. By using the interval analysis, a new method for calculating the interval of the structural reliability as well as the reliability index is introduced in this paper, and the traditional probabilistic theory is incorporated with the interval analysis. Moreover, the new method preserves the useful part of the traditional probabilistic reliability theory, but removes the restriction of its strict requirement on data acquisition. Example is presented to demonstrate the feasibility and validity of the proposed theory.

关键词： Non-probabilistic Reliability Interval analysis Parameter estimation

A combined experimental and analytical method to determine the EHL friction force distribution between rollers and outer raceway in a cylindrical roller bearing

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Friction 2023年第8期11卷 1455-1469页

作者： Yu HOU Xi WANG di yang Zeliang XIAO School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment Changsha University of Science and TechnologyChangsha 410114China

Friction force is a crucial factor causing power loss and fatigue spalling of rolling element bearings.A combined experimental and analytical method is proposed to quantitatively determine the elastohydrodynamic lubrication(EHL)friction force distribution between rollers and outer raceway in a cylindrical roller bearing(CRB).An experimental system with the instrumented bearing and housing was developed for measuring radial load distribution and friction torque of bearings.A simplified model of friction force expressed by dimensionless speed,load,and material parameters was *** inequality constrained optimization problem was established and solved by using an experimental data-driven learning algorithm for determining the uncertain parameters in the *** effect of speed,load,and lubricant property on friction force and friction coefficient was discussed.

关键词： cylindrical roller bearing(CRB) elastohydrodynamic lubrication(EHL) friction force distribution friction torque combined method

Effect of roller shapes on strip buckling in a continuous annealing furnace

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 297-302页

作者： Jing yang di Tang Lan Su Hai-tao Jiang Quan yang National Engineering Research Center of Advanced Rolling University of Science and Technology Beijing Beijing 100083 China

The effect of roller shapes on strip buckling in a continuous annealing furnace was focused on. The tensile stress distribution, the transverse compressive stress, and the critical buckling stress of the strip were studied by the finite element method （FEM） when the flat roller, crown roller, single taper roller, and double taper roller were used, respectively. Simulation results show that strip buckling is most likely to occur with the crown roller, then the double taper roller, and finally the single taper roller. Also, strip buckling can not occur when the flat roller is used. Considering strip snaking, the single taper roller and double taper roller are suggested in the continuous annealing fur-nace. The double taper roller with a better strip snaking-prevention ability should be applied in the sections with high strip temperature, and the single taper roller with a better buckling-prevention ability should be used in the sections with low strip temperature.

关键词： steel strips buckling heat treating furnaces annealing rollers finite element method

High-resolution polarization-sensitive optical coherence tomography and optical coherence tomography angiography for zebrafish skin imaging

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Journal of Innovative Optical Health Sciences 2021年第6期4卷 131-144页

作者： di yang Zhuoqun Yuan Zihan yang Muyun Hu Yanmei Liang Institute of Modern Optics Nankai University Tianjin Key Laboratory of Micro-scale Optical Information Science and TechnologyTianjin 300350P.R.China

Zebrafish is an important animal model,which is used to study development,pathology,and genetic *** zebrafish skin model is widely used in cutaneous research,and angiogenesis is critical for cutaneous wound ***,limited by the penetration depth,the available optical methods are difficult to describe the internal skin structure and the connection of blood vessels between the skin and subcutaneous *** a homemade high-resolution polarization-sensitive optical coherence tomography(PS-OCT)system,we imaged the polarization contrast of zebrafish skin and the zebrafish skin vasculature with optical coherence tomography angiography(OCTA).Based on these OCT images,the spatial distribution of the zebrafish skin vasculature was ***,we monitored the healing process of zebrafish cutaneous *** think the high-resolution PS-OCT system will be a promising tool in studying cutaneous models of zebrafish.

关键词： Polarization-sensitive optical coherence tomography optical coherence tomography angiography zebrafish skin vasculature

X-ray tomography analysis of aluminum alloy powder compaction

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Rare Metals 2022年第9期41卷 3244-3250页

作者： Shi-di yang Rui-Jie Zhang Xuan-Hui Qu State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing100083China School of Material Science and Engineering University of Science and Technology BeijingBeijing100083China

Aluminum alloy green compacts obtained by single-action compaction in lubricated and unlubricated dies were investigated by X-ray *** the purpose of obtaining the relationship between the density of green compact and the gray value of reconstructed images,linear fitting was *** results show that these data have excellent linear ***,a new method for analysis of compaction process was presented in this *** quantitative analysis of the density and compressive pressure distribution in green compacts was *** compressive pressure transmitted ratio and friction index were also *** is found that the lubricated die wall has better effects on the density homogeneity at lower applied compressive *** compaction process,the densification of powder particles in the die mainly occurs in the lower part of the green compact and the factor which mainly influences the friction between die wall and green compact is the applied compressive pressure.

关键词： Green compact Density distribution Compaction Compressive pressure distribution

Restoration of Ultimate Strength of Dented Hemispheres Under External Hydrostatic Pressure

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China Ocean Engineering 2022年第3期36卷 500-507页

作者： HUANG Chen ZHANG Jian WANG Fang di Chen-yang School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Shanghai Engineering Research Center of Hadal Science and Technology Shanghai Ocean UniversityShanghai 201306China

This study aimed to restore the ultimate strength of dented stainless-steel hemispheres with a radius of 90 mm and a thickness of 0.86 *** of the hemispheres were subjected to external hydrostatic *** stainless-steel stiffened caps were used to eliminate the effect of indention on the ultimate *** caps had a radius of 36 mm,a thickness of 0.76 mm,and a height of 10.44 *** hemispherical samples,including two intact hemispheres,two dented hemispheres without stiffening,and two dented hemispheres with stiffening,were *** hemi-sphere was geometrically measured for shape and thickness,hydrostatically tested for destruction,and numerically evaluated for *** experimental and numerical data agreed well with each *** a result,a spherical cap can effectively restore the ultimate strength of dented hemispheres under external hydrostatic *** proposed restoration approach can be used to strengthen underwater pressure hulls with large local geometric imperfections.

关键词： hemisphere restoration ultimate strength hydrostatic pressure buckling