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Energy optimization and experimental for a permanent magnet-biased redial magnetic bearing

Guangxue Jingmi Gongcheng/Optics and Precision Engineering 2019年第11期27卷 2420-2428页

作者： Liu, Qiang Zhao, Ming-Shi Han, Bang-Cheng Fan, Ya-Hong Sun, Jin-Ji Zheng, Shi-Qiang Institute of Precision Electromagnetic Equipment and Advanced Measurement Technology Beijing Institute of Petrochemical Technology Beijing102617 China Key Laboratory of Inertial Technology Beihang University Beijing100191 China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control Engineering Beijing100190 China

To address the requirement for low power of a magnetically suspended flywheel, the energy optimization of permanent magnet-biased radial magnetic bearing is studied. The magnetic circuit and working principles are introduced, based on the current stiffness and displacement stiffness mathematical models of a magnetic bearing, and the energy optimization factor σ of a magnetic bearing is obtained. The objective function of the power consumption of the magnetic bearing is then established, followed by optimization of the consumption. Subsequently, a mathematical expression for optimal power consumption and the value of σ are determined. The power consumption of the magnetic bearing is simulated and verified using the finite element method. The obtained results are tallied with the results of the theoretical analysis. Finally, based on the results of the optimization, a magnetic bearing is developed and power consumption is tested to improve the existing 15-Nms magnetically suspended flywheel. The results show that when the amplitude is 10 μm, the value of optimal power consumption for each winding is 0.85 W, with a maximum error of 7% compared with the theoretical optimal power consumption of 0.79 W. The designed efficiency of a magnetic bearing consuming low power is improved using the energy optimization method, which is important for the power optimization of flywheel systems. © 2019, Science Press. All right reserved.

关键词： Finite element method

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Data-driven optimization algorithm for economic operation of microgrid based on dynamic Kriging model and two-stage search strategy

Research Square

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Research Square 2021年

作者： Fan, Chaodong Hou, Bo Qu, Xilong Xiao, Leyi Cheng, Fanyong Hunan Provincial Key Laboratory of Finance & Economics Big Data Science and Technology School of Information Technology and Management Hunan University of Finance and Economics Changsha410205 China Key Laboratory of Advanced Perception and Intelligent Control of High-end Equipment Ministry of Education Anhui Polytechnic University Wuhu241000 China Foshan Green Intelligent Manufacturing Research Institute Xiangtan University Guangdong 528311 China School of Electrical and Electronic Engineering Nanyang Technological University Singapore639798 Singapore School of Automation and Electronic Information Xiangtan University Xiangtan411105 China

The economic operation optimization of microgrid is an important research topic in the power system. Therefore, this paper proposes a surrogate model particle swarm optimization algorithm based on the global-local search mechanism. Firstly, aiming at the problem that the statistical information of Kriging model is difficult to guarantee the prediction accuracy, the dynamic transformation is carried out to enhance the robustness of the model;secondly, the global-local search mechanism is introduced to make the algorithm fully explore the fitness landscape near the Kriging model after quickly locating the current optimal particle position, so as to achieve the balance of convergence quality and convergence efficiency. The proposed method has been tested on numerous benchmark test functions from two test suites, and the results show that the proposed algorithm has more advantages than other comparison algorithms in optimization accuracy. Finally, simulations are carried out in two operating modes of microgrid islanding and grid-connected, which has verified the effectiveness of the proposed method. © 2021, CC BY.

关键词： Particle swarm optimization (PSO)

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Fragile topologically protected perfect reflection for acoustic waves

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Physical Review Research 2020年第1期2卷 013131-013131页

作者： Chang-Yin Ji Yongyou Zhang Yunhong Liao Xiaoming Zhou Jian-Hua Jiang Bingsuo Zou Yugui Yao Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems and School of Physics Beijing Institute of Technology Beijing 100081 China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of Education and School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 People's Republic of China School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou China

Fragile topology is firstly demonstrated in acoustic crystals and then a realistic scheme is proposed to manipulate the transport of acoustic topological edge states (ATESs), i.e., by coupling them with side acoustic cavities. We find that single-mode cavities can completely flip the ATES pseudospin to form a perfect reflection, as long as their resonant frequencies fall into the topological band gap. The perfect reflection of the ATESs is protected by the fragile topology, which is proved by the one-dimensional topological waveguide-cavity transport theory. This fragile topologically protected perfect reflection is immune to the conventional defects (such as bending and disorder) and provides a realistic paradigm for manipulating the ATES transport. As examples, two potential applications, i.e., distance sensors and acoustic switches, are proposed based on the perfect reflection.

关键词： Acoustic wave phenomena Quantum transport Topological insulators

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Ultrasonic flexible microextrusion forming of ZK60 Mg alloy at room temperature

Ultrasonic flexible microextrusion forming of ZK60 Mg alloy ...

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第二届材料科学应用与能源材料国际研讨会

作者： Yan Lou Xiao Liu Shenzhen Key Laboratory of Advanced Manufacturing Technology for Mold & Die College of Mechatronics and Control EngineeringShenzhen University

A novel method of ZK60 magnesium formed through ultrasonic flexible microextrusion at room temperature was developed.A self-designed apparatus was applied for the ultrasonic flexible microextrusion *** results showed that the forming ability and surface quality of products was improved via ultrasonic flexible microextrusion forming *** extrusion stress distribution could be more uniform by using ultrasonic plasticizing flexible punch,compared with rigid punch.

关键词： Ultrasonic flexible microextrusion forming of ZK60 Mg alloy at room temperature

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Dual-band nonreciprocal thermal radiation by coupling optical Tamm states in magnetophotonic multilayers

arXiv

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arXiv 2021年

作者： Wu, Jun Wu, Feng Zhao, Tiancheng Antezza, Mauro Wu, Xiaohu Key Laboratory of Advanced Perception and Intelligent Control of High-end Equipment Ministry of Education College of Electrical Engineering Anhui Polytechnic University Wuhu241000 China School of Optoelectronic Engineering Guangdong Polytechnic Normal University Guangzhou510665 China Beijing Aerospace Institute for Metrology and Measurement Technology Beijing100076 China UMR 5221 CNRS-Universitéde Montpellier MontpellierF-34095 France Institut Universitaire de France 1 rue Descartes Paris Cedex 05F-75231 France Shandong Institute of Advanced Technology Jinan250100 China

Kirchhoff’s law is one of the most fundamental law in thermal radiation. The violation of traditional Kirchhoff’s law provides opportunities for higher energy conversion efficiency. Various micro-structures have been proposed to realize single-band nonreciprocal thermal emitters. However, dual-band nonreciprocal thermal emitters remain barely investigated. In this paper, we introduce magneto-optical material into a cascading one-dimensional (1-D) magnetophotonic crystal (MPC) heterostructure composed of two 1-D MPCs and a metal layer. Assisted by the nonreciprocity of the magneto-optical material and the coupling effect of two optical Tamm states (OTSs), a dual-band nonreciprocal lithography-free thermal emitter is achieved. The emitter exhibits strong dual-band nonreciprocal radiation at the wavelengths of 15.337 μm and 15.731 μm when the external magnetic field is 3 T and the angle of incidence is 56°. Besides, the magnetic field distribution is also calculated to confirm that the dual-band nonreciprocal radiation originates from the coupling effect between two OTSs. Our work may pave the way for constructing dual-band and multi-band nonreciprocal thermal emitters. Copyright © 2021, The Authors. All rights reserved.

关键词： Conversion efficiency

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Dual-Comb Ranging

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Engineering 2018年第6期4卷 772-778页

作者： Zebin Zhu Guanhao Wu State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China Division of Advanced Manufacturing Graduate School at ShenzhenTsinghua UniversityShenzhen 518055China

Absolute distance measurement is a fundamental technique in mobile and large-scale dimensional ***-comb ranging is emerging as a powerful tool that exploits phase resolution and frequency accuracy for high-precision and fast-rate distance *** two coherent frequency combs,dual-comb ranging allows time and phase response to be measured *** breaks through the limitations related to the responsive bandwidth,ambiguity range,and dynamic measurement characteristics of conventional ranging *** review introduces dual-comb ranging and summarizes the key techniques for realizing this ranging *** optical frequency comb technology progresses,dualcomb ranging shows promise for various professional applications.

关键词： Ranging Dual-comb interferometer Phase noise Timing jitter Tight-locking Post-correction

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Simulation investigation into mechanics behaviour in material removal process of ultrasonic assisted grinding of silicon carbide ceramics

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International Journal of Abrasive technology 2018年第4期8卷 310-328页

作者： Cao, Jianguo Liu, Yueming Nie, Meng Zhang, Qinjian School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Ministry of Education Beijing100044 China

Grinding force and stress in the ultrasonic assisted grinding (UAG) influence on the material removal behaviour. In this study, the simulation investigation of the material removal process, by ultrasonic assisted scratching (UAS) of silicon carbide using a single abrasive grain in UAG was conducted, to reveal the grinding force and stress variation behaviour. Conventional scratching (CS) without ultrasonic vibration was also carried out on the same condition for comparison. The results showed that: 1) the cutting forces in UAS undergo a periodic sinusoidal change, whereas those in CS are basically stabilised to a certain level after the tool cuts into the workpiece completely;2) the stress distribution fields on the cross and top surfaces along the cutting direction become wider in UAS than in CS;3) the kinetic energy of the grain consumed in UAS is bigger than that in CS, leading to the impact of the grain on the workpiece. Copyright © 2018 Inderscience Enterprises Ltd.

关键词： Grinding (machining)

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Quantitative study on abrasive belt wear based on geometric parameters

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key Engineering Materials 2018年第1期764卷 156-163页

作者： He, Zhe Li, Jianyong Wu, Yuefeng Liu, Yueming School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Ministry of Education Beijing100044 China

In this paper, based on micro wear form, an approach that using protrusion height, average tool angle, blunt area ratio and coated density to describe the wear of abrasive belt is put forward. The method for calculating the above parameters are also introduced. In experiments, we use the profilometer to collect the abrasive belt surface data and draw figures of the above parameters under service time, which indicates that using topography parameters can describe the degree of belt wear. According to parameters changing slope, the abrasive belt service time is roughly divided into two stages, initial wear stage and stable wear stage but no abrupt wear stage. Initial worn stage grains suffer more stress, patterns of wear are mainly severe wear and pull-off, while stable wear stage grains bear less stress and pattern of worn is dominated by mild wear. In addition to that, the other parameters changing trend is agreed and synchronous with protrusion height. © 2018 Trans Tech Publications, Switzerland.

关键词： Topography

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Regeneration mechanism, modification strategy, and environment application of layered double hydroxides: Insights based on memory effect

引用

Coordination Chemistry Reviews 2022年 450卷

作者： Haoyang Ye Shiyu Liu Deyou Yu Xuerong Zhou Lei Qin Cui Lai Fanzhi Qin Mingming Zhang Wenjing Chen Wenfang Chen Ling Xiang College of Environmental Science and Engineering Hunan University and Key Laboratory of Environmental Biology and Pollution Control Hunan University Ministry of Education Changsha Hunan 410082 PR China Key Laboratory of Advanced Textile Materials and Manufacturing Technology Ministry of Education School of Textile Science and Engineering Zhejiang Sci-Tech University Hangzhou 310018 PR China

Layered double hydroxides (LDHs), are ideal inorganic materials for versatile fields, such as catalysis, energy, and medicine. Memory effect means the ability of reconstruction into their initial structure after decomposition treatment for some special materials. Based on the unique property, the layered structure can be regenerated from the calcined LDHs (layered double oxide, LDO) in an aqueous solution or moist air. This effect provides a new paradigm for modification of LDHs, increasing the abundance of active sites in LDHs as well as preserves original active sites for multifunctional environmental applications. Therefore, this review summarizes the memory effect of LDHs from basic mechanisms to real applications. Firstly, various kinds of active sites on LDHs/LDOs and the importance of sites structure are concluded. Secondly, the modification methods of LDHs are briefly introduced and the characteristics of memory effect are summarized. Then, the mechanism of chemical reaction, topology, and thermodynamics of memory effect are discussed as well as the microscopic mechanism of memory effect through theoretical chemical calculation. The influencing factors and applications in environmental remediation are also presented. Finally, the challenges and prospects of memory effect-based LDHs are proposed. We hope the review could open a new path for the environmental application of memory effect-based LDHs.

关键词： Layered double hydroxide Layered double oxide Catalysis Adsorption Memory effect

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Electronic nature of chiral charge order in the kagome superconductor CsV3Sb5

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Physical Review B 2021年第7期104卷 075148-075148页

作者： Zhiwei Wang Yu-Xiao Jiang Jia-Xin Yin Yongkai Li Guan-Yong Wang Hai-Li Huang Sen Shao Jinjin Liu Peng Zhu Nana Shumiya Md Shafayat Hossain Hongxiong Liu Youguo Shi Junxi Duan Xiang Li Guoqing Chang Pengcheng Dai Zijin Ye Gang Xu Yanchao Wang Hao Zheng Jinfeng Jia M. Zahid Hasan Yugui Yao Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Beijing 100081 China Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems Beijing Institute of Technology Beijing 100081 China Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7) Department of Physics Princeton University Princeton New Jersey 08544 USA School of Physics and Astronomy Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education) Shenyang National Laboratory for Materials Science Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Superhard Materials College of Physics Jilin University Changchun 130012 China International Center for Computational Method and Software College of Physics Jilin University Changchun 130012 China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore Department of Physics and Astronomy Rice University Houston Texas 77005 USA Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Wuhan Hubei 430074 China Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Materials Science Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA Quantum Science Center Oak Ridge Tennessee 37831 USA

Kagome superconductors with TC up to 7 K have been discovered for over 40 y. Recently, unconventional chiral charge order has been reported in kagome superconductor KV3Sb5, with an ordering temperature of one order of magnitude higher than the TC. However, the chirality of the charge order has not been reported in the cousin kagome superconductor CsV3Sb5, and the electronic nature of the chirality remains elusive. In this paper, we report the observation of electronic chiral charge order in CsV3Sb5 via scanning tunneling microscopy (STM). We observe a 2 × 2 charge modulation and a 1 × 4 superlattice in both topographic data and tunneling spectroscopy. 2 × 2 charge modulation is highly anticipated as a charge order by fundamental kagome lattice models at van Hove filling, and is shown to exhibit intrinsic chirality. We find that the 1 × 4 superlattices form various small domain walls, and can be a surface effect as supported by our first-principles calculations. Crucially, we find that the amplitude of the energy gap opened by the charge order exhibits real-space modulations, and features 2 × 2 wave vectors with chirality, highlighting the electronic nature of the chiral charge order. STM study at 0.4 K reveals a superconducting energy gap with a gap size 2Δ=0.85meV, which estimates a moderate superconductivity coupling strength with 2Δ/kBTC=3.9. When further applying a c-axis magnetic field, vortex core bound states are observed within this gap, indicative of clean-limit superconductivity.

关键词： Charge density waves Density of states Electronic structure Superconducting gap Topological materials

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