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Research Square 2021年

作者： Li, Shuangbao Wang, Tingting Chen, Jianen Research Institute of Science and Technology Innovation Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A new highly efficient elastic-impact bistable nonlinear energy sink (EI-BNES) based on magnetic-elastic impacts with negative stiffness and bistability is proposed and optimized through global dynamical analysis. The EI-BNES has better robustness and higher energy dissipation rates with nearly more than 96.5% for broadband impulsive excitations than the traditional cubic NESs and single bistable NESs. The structure of negative stiffness impacts is realized by reasonable layout of permanent ring magnets and springs. A two-degree-of-freedom (two-DOF) elastic-impact system is established to describe the coupled nonlinear interaction between the main structure and the attached EI-BNES. A global Melnikov reduction analysis (GMRA) is proposed to study global dynamics and homoclinic bifurcations of the reduced two-dimensional subsystem, which is used to explain the mechanism of nonlinear targeted energy transfer (TET) and detect the threshold of impulsive amplitudes of EI-BNES for in-well and compound motions between in-well and cross-well resonance responses. A special type of saddle-center equilibrium points is also found in the non-smooth system of the EI-BNES and can be used to effectively increase the energy dissipation rates. The optimal design criterion of the tuned EI-BNES for better dissipation performance is also first discussed based on the GMRA and numerical techniques for calculating the Melnikov function of the non-smooth systems. The effectiveness of the analytical GMRA is also verified by numerical simulations. © 2021, CC BY.

关键词： Stiffness

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The Qitai Radio Telescope

arXiv

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arXiv 2023年

作者： Wang, Na Xu, Qian Ma, Jun Liu, Zhiyong Liu, Qi Zhang, Hailong Pei, Xin Chen, Maozheng Manchester, Richard N. Lee, Kejia Zheng, Xingwu Kärcher, Hans J. Zhao, Wulin Li, Hongwei Li, Dongwei Süss, Martin Reichert, Matthias Zhu, Zhongyi Wang, Congsi Li, Mingshuai Li, Rui Li, Ning Kazezkhan, Guljaina Yan, Wenming Wu, Gang Cui, Lang Zhang, Ming Li, Haitao Xinjiang Astronomical Observatory Chinese Academy of Sciences Urumqi830011 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing210008 China Xinjiang Key Laboratory of Radio Astrophysics Urumqi830011 China Xinjiang Key Laboratory of Microwave Technology Urumqi830011 China Australia Telescope National Facility CSIRO Space and Astronomy PO Box 76 EppingNSW1710 Australia Department of Astronomy Peking University Beijing100871 China School of Astronomy and Space Science Nanjing University Nanjing210093 China Dr. Hans Jürgen Kärcher Engineering Office Karben61184 Germany Northwest China Research Institute of Electronic Equipment Xi’an710065 China Mainz55130 Germany Beijing Institute of Architectural Design Beijing100045 China Xidian University Guangzhou Institute of Technology Guangzhou510555 China

This study presents a general outline of the Qitai radio telescope (QTT) project. Qitai, the site of the telescope, is a county of Xinjiang Uygur Autonomous Region of china, located in the east Tianshan Mountains at an elevation of about 1800 m. The QTT is a fully steerable, Gregorian-type telescope with a standard parabolic main reflector of 110 m diameter. The QTT has adopted an umbrella support, homology-symmetric lightweight design. The main reflector is active so that the deformation caused by gravity can be corrected. The structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to 115 GHz. To satisfy the requirements for early scientific goals, the QTT will be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers. A multi-function signal-processing system based on RFSoC and GPU processor chips will be developed. These will enable the QTT to operate in pulsar, spectral line, continuum and Very Long Baseline Interferometer (VLBI) observing modes. Electromagnetic compatibility (EMC) and radio frequency interference (RFI) control techniques are adopted throughout the system design. The QTT will form a world-class observational platform for the detection of low-frequency (nanoHertz) gravitational waves through pulsar timing array (PTA) techniques, pulsar surveys, the discovery of binary black-hole systems, and exploring dark matter and the origin of life in the universe. The QTT will also play an important role in improving the Chinese and international VLBI networks, allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing systems. Deep astrometric observations will also contribute to improving the accuracy of the celestial reference frame. Potentially, the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence. © 2023, CC BY.

关键词： Ultra-wideband (UWB)

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Reform and Practice in Experimental Teaching from the View of "Emerging Engineering": Case Study on the Field of Energy and Power Engineering

Reform and Practice in Experimental Teaching from the View o...

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Information Communication Technologies Conference (ICTC)

作者： He Tian Lijian Liu Miao Tian Shimin Zhou Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) School of Mechanical Engineering Tianjin University of Technology Tianjin China Tianjin Academy of Educational Science Tianjin China Tianjin Newborn New Energy Technology Co. Ltd Tianjin China

According to the idea of "Emerging Engineering Education" talent training model of Ministry of Education, students should be trained to have "metaphysical" concept, connection, imagination, macro thinking. Project-driven experiment teaching focuses on a project, and the goal is the completion of the project; the student is the center of teaching activities, which is supported by the inquiry process. This study analyzes the significance of the project-driven method in experimental teaching. This paper describes the implementation process of experimental teaching in the field of energy and power engineering in terms of project design, teaching system construction and so on under the project-driven method. By analyzing the results of a questionnaire survey distributed to students of energy and power in the College of Mechanical Engineering at the Tianjin University of technology, it is found that the students are satisfied with the effects of project-driven experimental teaching, and the use of experimental teaching has greatly aroused the students' enthusiasm for learning. The ability of the students to engage in autonomous learning, engineering practice and innovation has been greatly improved, and a good teaching effect has been achieved.

关键词： Training Power engineering Technological innovation Education Solids Communications technology Mechanical engineering

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An Approach on Visual Detecting Multi-Targets in the Unstructured and Complex Scenes Based on RGB-D Images 5

An Approach on Visual Detecting Multi-Targets in the Unstruc...

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5th International Conference on Automation, Control and Robotics Engineering, CACRE 2020

作者： Tan, Qimeng Sun, Yikun Xin, Pengfei Lin, Yimin Ma, Chao Wang, Xinyu Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing China Beijing Special Engineering Design and Research Institute Propellant Injection Laboratory Beijing China Beijing University of Posts Telecommunications Institute of Optical Communication Optoelectronics Beijing China Beijing Information Science and Technology University School of Instrument Science and Optoelectronic Engineering Beijing China

ISBN: (纸本)9781728198880

The technology of detecting and identifying multitarget is of significance for robotic visual navigation within the unknown, unstructured, complex scenes, whose result could be considered as important references of 3D map building and path planning for mobile robot. Traditional algorithms of target detection can be applied to 2D images without depth information generally, which is disturbed by few factors such as illumination, view and scale easily. Therefore, an approach on visual detecting multi-target of unstructured and complex scenes based on RGBD images is proposed in this article to solve the above problem, which is composed of extracting descriptor of rotation and scale invariance feature, local encoding of targets, random ferns classifier training, Hough map generation, Hough voting theoretical model and local maximum search. Experimental results have shown that the proposed approach reduce the calculation of extracting and matching local feature, improve the accuracy of object recognition and detection in unknown complex environments, be capable of well robust against few disturbing factors i.e. rotation, scale, illumination, occlusion and non-rigid body deformation. © 2020 IEEE.

关键词： Motion planning

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Tension Characteristics Analysis of Scraper Chain of Heavy-Duty Scraper Conveyor with Time-Varying Loads

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Shock and Vibration 2024年第1期2024卷

作者： Shuai Li Zhencai Zhu Hao Lu Yujun Xue School of Mechatronics Engineering Henan University of Science and Technology Luoyang 471003 China *** Henan Key Laboratory for Machinery Design and Transmission System Luoyang 471003 China Collaborative Innovation Center of Henan Province for High-End Bearing Henan University of Science and Technology Luoyang 471000 China *** Longmen Laboratory Luoyang 471000 China School of Mechatronics Engineering Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment China University of Mining and Technology Xuzhou 221116 Jiangsu China ***

With the intensification and large scale of coal mining, scraper conveyors are developing towards high power, large volume, long haul distance, and high reliability. It is more and more important to obtain the dynamic tension of the scraper chain with time-varying loads. The purpose of this paper is to obtain the dynamic tension of scraper chains of the scraper conveyor with time-varying loads. First, according to the structural characteristics and working environment of the scraper conveyor and the polygon effect of the sprocket, the scraper conveyor dynamic model under the action of the time-varying loads is established by the finite unit method. Second, the load variation rule of the bearing section is explored when the scraper conveyor and shearer work together. Furthermore, the element resistance of each discrete element, the stiffness coefficient of the scraper chain, and the influence of polygonal effect of sprocket wheel are analyzed. And then, the dynamic tension of the scraper chain is obtained by the Hilber–Hughes–Taylor (HHT) method. Finally, the validity of the scraper conveyor dynamic model is verified by the example analysis and field measurement experiment. Due to the influence of heavy starting, the maximum tension of the scraper chain during the starting process is 751.6 kN, which is 12.25% higher than the tension with smooth running (669.6 kN). During the startup stage, significant impacts occur on both motors and scraper chains which may lead to damage. To protect these components effectively, control strategies such as “soft start” or no-load start hold crucial engineering significance in achieving reliable operation of the scraper conveyor. The obtained results can provide a theoretical basis for the reliability evaluation and parameter optimization of the scraper conveyor.

关键词：

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The Application of Adaptive A-star Algorithm in Layout of Spatial Pipeline

The Application of Adaptive A-star Algorithm in Layout of Sp...

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Data Driven Control and Learning systems (DDCLS)

作者： Xinyu Zhao Na Qin Jie Huang Yongchen Miao the Institute of Systems Science and Technology Southwest Jiaotong University Chengdu China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Harbin Shipping School Harbin China

ISBN: (数字)9781728159225

ISBN: (纸本)9781728159232

In order to settle the complex problem of layout of spatial pipeline, the diameter of pipeline is taken as the distance between adjacent scattered points, and the spatial layout including obstacles is approximated as a three-dimensional diagram of scattered points. A-star algorithm is used to search an optimal pipelines path from the three-dimensional diagram of scattered points. However, when traditional A-star algorithm addresses pre-selected points that are the same cost, it selects pre-selected points randomly. In view of the disadvantages, an adaptive A-star algorithm is proposed based on the traditional A-star algorithm, in this paper. The adaptive A-star algorithm selects more reasonable pre-selected point according to the surrounding environment and situation of pre-selected point , so as to achieve the requirements of the shortest pipeline and the fewest inflection point. Finally, the experimental simulation shows that the adaptive A-star algorithm has better performance than the traditional A-star algorithm.

关键词： Pipelines Path planning Layout Robots Heuristic algorithms Robot kinematics Optimization

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Research about the influence of passive residual heat removal system on SGTR accident 27

Research about the influence of passive residual heat remova...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Wu, Yirui Shan, Jianqiang Xu, Tao Ma, Haifu Yang, Junyun Yu, Hong Wang, Junlong School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an Shaanxi Province China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan Province China

ISBN: (纸本)9784888983051

Since the passive safety system turns out to be a desirable method to achieve simplification and increase the reliability of the performance of essential safety functions, passive technology with inherent safety features has been generally applied to the design of advanced nuclear power plant. The PWR (pressurized water reactor) NPP (nuclear power plant) in this paper is a kind of mature pressurized water plants in china, and is proposed to be improved with some passive systems to enhance safety performance. The proposed and adapted passive safety systems for this PWR power plant in this paper contain: (1) the RMT (reactor makeup tank);(2) the A-ACC (advanced accumulators);(3) the IRWST (in-containment refueling water storage tank);(4) the PDS (passive depressurization system);(5) the PRHRS (passive residual heat removal system), which is installed on the reactor coolant system (RCS) loop. In this research, the behaviors of passive safety systems are studied and transient characteristics of the primary and secondary side of the reactor during the Steam Generator Tube Rupture (SGTR) accident are investigated using the best-estimate transient simulation code Relap5/MOD3.3. Results reported in this paper indicate that making use of passive safety systems especially the PRHRS could ensure reactor safety during the SGTR accident. Copyright © 2018-2019 by JSME

关键词： Pressurized water reactors

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Diff9D: Diffusion-Based Domain-Generalized Category-Level 9-DoF Object Pose Estimation

arXiv

引用

arXiv 2025年

作者： Liu, Jian Sun, Wei Yang, Hui Deng, Pengchao Liu, Chongpei Sebe, Nicu Rahmani, Hossein Mian, Ajmal National Engineering Research Center for Robot Visual Perception and Control Technology College of Electrical and Information Engineering School of Robotics State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha410082 China Institute of Artificial Intelligence and Robotics Xi’an Jiaotong University Xi’an710049 China Department of Information Engineering and Computer Science University of Trento Trento38123 Italy School of Computing and Communications Lancaster University LA1 4YW United Kingdom Department of Computer Science The University of Western Australia WA6009 Australia

Nine-degrees-of-freedom (9-DoF) object pose and size estimation is crucial for enabling augmented reality and robotic manipulation. Category-level methods have received extensive research attention due to their potential for generalization to intra-class unknown objects. However, these methods require manual collection and labeling of large-scale real-world training data. To address this problem, we introduce a diffusion-based paradigm for domain-generalized category-level 9-DoF object pose estimation. Our motivation is to leverage the latent generalization ability of the diffusion model to address the domain generalization challenge in object pose estimation. This entails training the model exclusively on rendered synthetic data to achieve generalization to real-world scenes. We propose an effective diffusion model to redefine 9-DoF object pose estimation from a generative perspective. Our model does not require any 3D shape priors during training or inference. By employing the Denoising Diffusion Implicit Model, we demonstrate that the reverse diffusion process can be executed in as few as 3 steps, achieving near real-time performance. Finally, we design a robotic grasping system comprising both hardware and software components. Through comprehensive experiments on two benchmark datasets and the real-world robotic system, we show that our method achieves state-of-the-art domain generalization performance. Our code will be made public at https://***/CNJianLiu/Diff9D. Copyright © 2025, The Authors. All rights reserved.

关键词： Augmented reality

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Comparison of SGTR accident with two different passive residual heat removal systems 27

Comparison of SGTR accident with two different passive resid...

引用

27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Wu, Yirui Shan, Jianqiang Xu, Tao Ma, Haifu Yang, Junyun Yu, Hong Wang, Junlong Deng, Yaxin School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an Shaanxi Province China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan Province China

ISBN: (纸本)9784888983051

Since the passive safety system turns out to be a desirable method to achieve simplification and increase the reliability of the performance of essential safety functions, passive technology has been generally applied to the design of advanced nuclear power plant. The traditional generation II+ nuclearpower plant is proposed to be improved with some passive systems to enhance safety performance. There are two series of passive safety systems for this kind of nuclear power plant in this paper, one of them contains: (1) the RMT (reactor makeup tank);(2) the A-ACC (advanced accumulators);(3) the IRWST (in-containment refueling water storage tank);(4) the PDS (passive depressurization system);and (5) the PRHRS (passive residual heat removal system), which is installed on the reactor coolant system (RCS) loop;the other contains:(1) the RMT (reactor makeup tank);(2) the A-ACC (advanced accumulators);(3) the IRWST (in-containment refueling water storage tank);(4) the PDS (passive depressurization system);(5) the PEFS(passive emergency feed water system), which is installed on the secondary side of SGs. In this research, the transient characteristics of SGTR accident with the two different passive residual heat removal systems which are PRHRS and PEFS is investigated using the best-estimate transient simulation code Relap5/MOD3.3. The calculation results show that both of PRHRS and PEFS could remove the decay heat from the primary loop efficiently to ensure the reactor safety and reduce the radioactive leakage to mitigate the accident impact during the SGTR accident. Due to the significant cooling effect of PRHRS and PEFS, the water level of broken SG would not be overfilled in both conditions, which is different with the SGTR accident of traditionalgeneration II+nuclear power plant. Compared with the PEFS, the PRHRS performed better in cooling efficiency, long-term cooling performance, reducing radioactive leakage capacity and mitigating accident effect. Copyright © 2018-2

关键词： Nuclear power plants

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Coupling effects of Zn single atom and high curvature supports for improved performance of CO_(2) reduction

引用

science Bulletin 2021年第16期66卷 1649-1658,M0004页

作者： Zhongjing Hao Junxiang Chen Dafeng Zhang Lirong Zheng Yueming Li Zi Yin Gang He Lei Jiao Zhenhai Wen Xiao-Jun Lv State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of New EnergyNorth China Electric Power UniversityBeijing 102206China State Key Laboratory of Metastable Materials Science and Technology College of Materials Science and EngineeringYanshan UniversityQinhuangdao 066004China CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Province Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Department of Energy and Chemical Engineering College of Chemistry and Chemical EngineeringHenan Key Laboratory of Coal Green ConversionHenan Polytechnic UniversityJiaozuo 454003China Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Single-atom catalysts(SACs)have emerged as one of the most competitive catalysts toward a variety of important electrochemical reactions,thanks to their maximum atom economy,unique electronic and geometric ***,the role of SACs supports on the catalytic performance does not receive enough research ***,we report an efficient route for synthesis of single atom Zn loading on the N-doped carbon nano-onions(ZnN/CNO).ZnN/CNO catalysts show an excellent high selectivity for CO_(2) electro-reduction to CO with a Faradaic efficiency of CO(FECO)up to 97%at -0.47 V(*** hydrogen electrode,RHE)and remarkable durability without activity *** our knowledge,ZnN/CNO is the best activity for the Zn based catalysts up to now,and superior to single atom Zn loading on the two-dimensional planar and porous structure of graphene substrate,although the graphene with larger surface *** exact role of such carbon nano-onions(CNO)support is studied systematically by coupling characterizations and electrochemistry with density functional theory(DFT)calculations,which have attributed such good performance to the increased *** increased curvature modifies the surface charge,which then changes the adsorption energies of key intermediates,and improves the selectivity for CO generation accordingly.

关键词： Single-atom catalysts Highly curved substrate Electrocatalytic CO_(2) reductions High activity and selectivity Coupling effect

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