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SSRN 2023年

作者： Wen, Shutao Zhao, Fei Li, Yulong Hu, Junzhi Tan, Yi Li, Pengting Ning, Lidan School of Mechanical Engineering Yangzhou University Yangzhou225127 China Shanghai University State Key Lab Adv Special Steel Shanghai200444 China School of Materials Science and Engineering Dalian University of Technology Dalian116024 China Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology Guangxi university Guangxi Nanning530003 China

Numerical simulations provide a new method to study the heat and mass transfer behavior during the electron beam evaporation (EBE) process, which can obtain some physical quantities that cannot be accurately measured in experiments. In this study, a mathematical model is established to investigate the evaporation behavior, the variation of temperature field and flow field of target material during the EBE process, and verified through experiments. The results show that the evaporation rate of target material is extremely non-uniform on the molten pool surface, which the calculation error of the evaporation rate was 3.47%. The solid-liquid interface obtained by numerical simulation is basically consistent with the experiment, which the calculation error of the molten pool depth was 2.86% and the calculation error of the molten pool width was 3.03%. In addition, the surface temperature and flow rate of the molten pool increased with the increase of the electron beam power, the depth and the width of the molten pool increased linearly with the increase of the electron beam power and then level off. The model can accurately describe the changes of temperature field and flow field during the EBE process, and then make reliable predictions based on the simulation results. © 2023, The Authors. All rights reserved.

关键词： Flow fields

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Analysis of the influence of wind farms in full operating conditions on the torsional vibration of the shaft system of synchronous generators

Analysis of the influence of wind farms in full operating co...

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2021 International Conference on Power system technology, POWERCON 2021

作者： Jia, Qi Zhai, Wenchao Zhang, Qiang Sun, Feng Shen, Mohan Research Institute State Grid Liaoning Electric Power Shenyang China Northeast Electric Power University Min. of Educ. Key Laboratory of Modern Power System Simulation Control and Green Power Technology Jilin China

ISBN: (纸本)9781665407373

The power oscillation induced by the large-scale integration of wind power into the power grid has become one of the important issues affecting the safe and stable operation of the power grid. Aiming at the dynamic interaction between wind farms and synchronous generators, based on the additional excitation signal injection method, the influence of DFIG and PMSG wind farms on the damping characteristics of each torsional vibration mode of synchronous generators under full operating conditions is analyzed. By applying an AC voltage signal at both ends of the field winding to stimulate rotational speed oscillation, observe the difference in the free response characteristics of rotational speed disturbances, identify the electromechanical coupling characteristics between the wind farm and the synchronous generator set, and reveal the influence of the wind farm type and operating conditions on the shaft system of the synchronous generator set. The mechanism of torsional vibration. Finally, the validity of the theoretical analysis is verified based on time-domain simulation. © 2021 IEEE.

关键词： Synchronous generators

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Surface Topography of the Metal surface in Robot Polishing under Control Force 2

Surface Topography of the Metal surface in Robot Polishing u...

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2020 2nd Asia Conference on Automation Engineering, ACAE 2020

作者： Zhao, Wenliang Mohsin, Imran Huang, Longlong He, Kai Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China Shenzhen Key Laboratory of Minimally Invasive Surgical Robotics and System Shenzhen China University of Chinese Academy of Sciences Beijing China Yanshan University Qinhuangdao Hebei China Chinese University of Hong Kong Hong Kong Hong Kong

Polishing is an important finishing process in the field of manufacturing, which enhances product quality and increases its life span. Compared with manual polishing, robotics polishing has advantages in terms of cost and productivity. This paper presents a new study on the surface topography of metal workpiece in the robotic polishing test. Various workpieces with different surface roughness were polished with the industrial robot under similar polishing parameters, and the variation of surface topography with polishing was studied utilizing microscopic scanning. © Published under licence by IOP Publishing Ltd.

关键词： Polishing

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Research on Detection Method of Effective Diameter of Defective Steel Bars in Concrete Structures

Research on Detection Method of Effective Diameter of Defect...

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Power systems and Electrical technology (PSET), IEEE International Conference on

作者： Lu Chunyi Zheng Tengfei Deng Bowen Dai Youquan State Grid Zhejiang Electric Power Company Lanxi Power Supply Company Jinhua China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

Reinforced concrete(RC) structures have become an indispensable building material in modern society, in which steel bars can significantly enhance the tensile and compressive properties of reinforced concrete integral components. When the steel bar diameter is reduced due to factors such as corrosion or manufacturing factors, the quality and service life of concrete members will be severely affected. Therefore, it is of great significance to accurately evaluate the effective diameter of reinforcing bars inside concrete members for the operation and maintenance of concrete members. Based on the magnetization principle of ferromagnetic materials, this paper innovatively proposes a detection method for judging the effective diameter of steel bars in concrete by using the magnetic induction value. The magnetic field distribution characteristics of steel bars with different diameters under a fixed magnetic field excitation source are studied, and the position of the diameter reduction interval is judged by the sudden change of the slope of the magnetic induction intensity curve. Curve fitting and integration were performed on the magnetic induction intensity values collected in the diameterreduced interval, and the ratio of the value to the curve integration under the normal diameter was used as the diameter criterion. Finally, by building an experimental platform, the validity of the criterion formed by the magnetic induction intensity curve for judging the diameter of steel bars in concrete is verified.

关键词： Magnetic flux density Power measurement Magnetization Fitting Concrete Data models Steel

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青藏高原发现3000年前的奶制品

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Science Bulletin 2023年第4期68卷 393-396,M0004页

作者：张予南高玉杨继帅王彦人王韵铭汪椿鑫范安川申旭科童艳拥措马志坤凌智永王辉杨晓燕陈发虎 State Key Laboratory of Tibetan Plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China School of Archaeology and Museology Peking UniversityBeijing 100871China Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China University of Chinese Academy of Sciences Beijing 100086China Department for the History of Science and Scientific Archaeology University of Science and Technology of ChinaHefei 230026China Tibetan Institute for the Preservation of Cultural Relics Lhasa 850015China Key Laboratory of Cultural Heritage Research and Conservation School of Cultural HeritageNorthwest UniversityXi’an 710127China Institute of Archaeology Chinese Academy of Social SciencesBeijing 100710China

奶制品的出现是新石器时代次级产品革命的标志之一,代表着对动物奶、毛、畜力等可以反复利用资源的开发,为早期农业和游牧社会的发展提供了基础.青藏高原人群现代食谱中肉、奶比例相对较高,但缺少史前奶制品利用的直接证据.陶器是新石... 详细信息

奶制品的出现是新石器时代次级产品革命的标志之一,代表着对动物奶、毛、畜力等可以反复利用资源的开发,为早期农业和游牧社会的发展提供了基础.青藏高原人群现代食谱中肉、奶比例相对较高,但缺少史前奶制品利用的直接证据.陶器是新石器时代古人最常用的烹饪和储存工具,检测陶器残留物的脂肪酸组成及碳同位素分布可以指示动物肉类和奶类来源.本文对西藏日喀则南木林县海拔约4000 m的共塘遗址出土陶片进行了脂质残留物分析,结果显示大约3000年前,在雅鲁藏布江中游地区,奶制品消费伴随着当地的牛羊等家养动物同时出现.

关键词：残留物分析新石器时代动物肉类南木林县家养动物西藏日喀则奶制品早期农业

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Enhanced Light-Harvesting Efficiency and Adaptation: A Review on Visible-Light-Driven Micro/Nanomotors

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研究（英文） 2020年第3期 116-140页

作者： Dekai Zhou Rencheng Zhuang Xiaocong Chang Longqiu Li Key Laboratory of Microsystems and Microstructures Manufacturing Harbin Institute of Technology Harbin Heilongjiang 150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang 150001 China

As visible light accounts for a larger proportion of solar energy and is harmless to living organisms,it has the potential to be the energy source of micro/nanomotors,which transform visible-light energy into mechanical motion,for different applications,especially in environmental ***,how to precisely control the motion of visible-light-driven micro/nanomotors (VLD-MNMs) and efficiently utilize the weak visible-light photon energy to acquire rapid motion are significant *** review summarizes the most critical aspects,involving photoactive materials,propulsion mechanisms,control methods,and applications of VLD-MNMs,and discusses strategies to systematically enhance the energyharvesting efficiency and *** first,the photoactive materials have been divided into inorganic and organic photoactive materials and comprehensively ***,different propulsion mechanisms of the current VLD-MNMs are presented to explain the improvement in the actuation force,speed,and environmental *** addition,considering the characteristics of easy control of VLD-MNMs,we summarized the direction,speed,and cluster control methods of VLD-MNMs for different application ***,the potential applications of VLD-MNMs,e.g.,in environmental remediation,micropumps,cargo delivery,and sensing in microscale,are ***,discussions and suggestions for future directions to enhance the energy-harvesting efficiency and adaptation of VLD-MNMs are provided.

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Research on Vibration Measurement and Characteristics of Converter Transformer Considering the Influence of Harmonics 2

Research on Vibration Measurement and Characteristics of Con...

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2nd IEEE China International Youth Conference on Electrical Engineering, CIYCEE 2021

作者： Jiang, Peiyu Zhang, Zhanlong Pan, Zhicheng Chongqing University State Key Laboratory of Power Transmission Equipment System Security and New Technology Chongqing400030 China Maintenance Test Center of EHV Power Transmission Company China Southern Power Grid Guangzhou510000 China

ISBN: (纸本)9781665400640

The vibration of the converter transformer is related to voltage and current. The high-voltage direct current transmission system contains a lot of harmonics, and the generated vibration and noise seriously affect its operating environment. The current research has not fully considered the impact of harmonics on vibration. In order to reveal the relationship between the two, this paper sets up a vibration measurement experiment, collects the vibration and voltage and current waveforms of the converter transformer box in operation, and analyzes the harmonic spectrum and the time-frequency characteristic distribution of vibration signals. The results prove that harmonics will shift the dominant frequency of vibration, and the valve-side voltage harmonics are one of the main causes of high-frequency vibration components. The research results provide a theoretical basis for the on-line diagnosis of vibration measurement technology and the suppression of vibration and noise. © 2021 IEEE.

关键词： Vibration measurement

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Application of Terahertz Spectroscopy in Defect Detection of Power Cable Terminal Insulation Material

Application of Terahertz Spectroscopy in Defect Detection of...

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International Conference on Infrared and Millimeter Waves

作者： C Zhidong Y Lijun C Li H Yuxin Country State Key Laboratory of Power Equipment & System Security and New Technology Chongqing University China

In this paper, Terahertz time domain spectroscopy system (THz-TDS) is introduced into the nondestructive testing of the defects of power cable insulation materials. Typical defects including air gap, conductive impurities and discharge channel. Samples of cable terminal insulation material with typical defects are tested using THz-TDS. Time-domain and frequency-domain spectrums of different defects are obtain and analysis. Finally, terahertz two-dimensional imaging test is carried out on cable terminal insulation materials with typical defects and defects are clearly visible in the imaging. Experimental results show that terahertz technology can be applied to the field of nondestructive testing of cable terminal insulation.

关键词： Spectroscopy Power cables Impurities Nondestructive testing Imaging Power cable insulation Terahertz materials

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A vector control method of PMSM using single phase current sensor

A vector control method of PMSM using single phase current s...

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2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Guo, Chuangqiang Wu, Chunya Ni, Fenglei Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang Province China

ISBN: (纸本)9781728163215

This paper presents a new method of realizing vector control for the surface mounted permanent magnet synchronous machine (PMSM) using single phase current sensor. A simplified estimating method of phase current, which only requires the information from single phase current sensor and motor position sensor, has been proposed in this paper. Compared with the classical approaches, based on the reference current in synchronous rotor frame, the proposed method can get better accuracy, especially when there is a sudden change of the reference current. Furthermore, the method not relays on the model and parameters of PMSM and the control performance of current close-loop and also not sensitive to working conditions. The extensively experimental results under different work conditions, based on MATLAB/SIMULINK, have validated the feasibility and robustness of the proposed vector control method. © 2019 IEEE.

关键词： Vectors

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Flexible Catch Claw-type Space Debris Capture Mechanism Based on Constant Torque Spring Deployment

Flexible Catch Claw-type Space Debris Capture Mechanism Base...

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IEEE International Conference on Mechatronics and Automation

作者： Kui Sun Kailun Chen State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang Province China

ISBN: (数字)9781728164168

ISBN: (纸本)9781728164175

Space debris cleaning technology can not only save scarce orbit resources, but also protect satellites and space stations in orbit, which has important research significance. Combination of reliability and adaptability is the key for space debris cleaning devices to capture debris. A design scheme of flexible catch claw-type space debris capture mechanism based on constant torque spring deployment is proposed, which has the advantages of light weight, high capture reliability and high adaptability. The new flexible catching mechanism is mainly composed of a multi-finger flexible catching claw, a transmission device, and a locking device. In the multi-finger flexible catching claw, a constant torque spring is used as a passive drive deployment mechanism, and a carbon fiber rod is used as an actuator. The transmission device uses a ball screw to drive the link mechanism to move. The locking device provides a controllable deployment function at a predetermined position. This paper introduces the structure design of the capture mechanism and the research on synchronized deployment of the catch claws. Finally, the kinetic simulation results for evaluating the capture performance are given.

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