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Multi-level coarse-grained discrete element method modeling of cylinder particle flow in a rotating drum

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Particuology 2024年第5期88卷 218-238页

作者： lei Xu Xiukai Wu Shuai Wang Shiyi bao Institute of Process Equipment and Control Engineering Zhejiang University of TechnologyHangzhou 310023China Engineering Research Center of Process Equipment and Remanufacturing Ministry of EducationZhejiang University of TechnologyHangzhou 310023China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

The coarse-grained discrete element method(DEM)is probably a feasible option for simulating an actual drum-type biomass boiler,which contains over 10 million cylinder particles.A multi-level study was conducted based on particle and coarse-grained level data to evaluate the adequacy of the coarse-grained approach in terms of geometrical characteristics,kinematic features,and dynamic *** scaling laws for contact parameters were used and compared during the *** results show that the coarse-grained approach can accurately predict the positions of the free surface and active-passive interface,the mixing index,and the orientation *** in the velocity fields may occur due to the worse flowability of coarse-grained particles near the free *** efficiency is significantly improved by the coarse-grained model compared with the corresponding original case(the same DEM code without a coarse-grained model was used for the original simulations).

关键词： Coarse-grained method Discrete element method(DEM) Cylinder particle Rotating drum Granular flow

A Modified Iterative Learning Control Approach for the Active Suppression of Rotor Vibration Induced by Coupled Unbalance and Misalignment

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 242-253页

作者： Yifan bao Jianfei Yao Fabrizio Scarpa yan Li College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of High-end Compressor and System Technology Beijing 100029China Beijing Key Laboratory of High-end Mechanical Equipment Health Monitoring and Self-Recovery Beijing University of Chemical TechnologyBeijing 100029China Key Lab of Engine Health Monitoring-Control and Networking of Ministry of Education Beijing University of Chemical TechnologyBeijing 100029China Bristol Composites Institute(ACCIS) University of BristolBristol BS81TRUK Dynamics and Control Research Group(DCRG) University of BristolBristol BS81TRUK

This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel *** control of the vibration of the rotor is provided by an active magnetic actuator(AMA).The iterative gain of the MILC algorithm here presented has a self-adjustment based on the magnitude of the *** filters are adopted to extract the synchronous(1×Ω)and twice rotational frequency(2×Ω)components of the rotor *** the notch frequency of the filter and the size of feedforward storage used during the experiment have a real-time adaptation to the rotational *** method proposed in this work can provide effective suppression of the vibration of the rotor in case of sudden changes or fluctuations of the rotor *** and experiments using the MILC algorithm proposed here are carried out and give evidence to the feasibility and robustness of the technique proposed.

关键词： Rotor vibration suppression Modified iterative learning control Unbalance Parallel misalignment Active magnetic actuator

Possible Involvement of Anti-Oxidant Enzymes in the Cross-Tolerance of the Germination/Growth of Wheat Seeds to Salinity and Heat Stress

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Journal of Integrative Plant Biology 2005年第10期47卷 1211-1219页

作者： yan-bao lei Song-Quan SONG Jia-Rui FU Xishuangbanna Tropical Botanical Garden the Chinese Academy of Sciences Yunnan 666303 China School of Life Sciences Sun Yat-Sen University Guangzhou 510275 China

The germination/growth of wheat （Triticum aestivum L. cv. Zimai 1） seeds and changes in the activities of superoxide dismutase （SOD）, ascorbate peroxidase （APX）, and catalase （CAT）, as well as in the content of thiobarbituric acid-reactive substances （TBARS）, in response to salt and heat stress, as well as cross-stress, were investigated in the present study. With increasing temperature and decreasing water potential caused by NaCI solution, the germination percentage of seeds and the fresh weight of seedlings decreased markedly, SOD activity increased, activities of APX and CAT decreased distinctly, and the TBARS content increased gradually. Seeds pretreated at 33℃ for different times displayed increased tolerance to subsequent salt stress, enhanced SOD, APX, and CAT activities, and decreased TBARS content. Seeds pretreated at -0.8 MPa NaCI for different times displayed increased tolerance to subsequent heat stress and marked increases in SOD, APX, and CAT activities, which were associated with decreased TBARS content. It is considered that the common component in the cross-tolerance of the germination and growth of wheat seeds to salinity and heat stress is the anti-oxidant enzyme system.

关键词： anti-oxidant enzymes cross tolerance germination growth heat stress salinity stress Triticum aestivum seeds.

Corrosion behavior of Gd_(2)Zr_(2)O_(7)thermal barrier coatings under Fe-containing environmental sediment attack

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Journal of Advanced Ceramics 2024年第4期13卷 447-462页

作者： lei Guo yanyan Li Kai yan School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin 300072China Key Laboratory of Special Equipment Safety and Energy-saving for State Market Regulation China Special Equipment Inspection&Research InstituteBeijing 100029China

Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ***_(2)Zr_(2)O_(7)TBCs are famous for their excellent CMAS *** this study,the characteristics of Fe-containing environmental sediments(CMAS-Fe)and their corrosiveness to Gd_(2)Zr_(2)O_(7)coatings were *** types of CMAS-Fe glass with different Fe contents were *** melting points were measured to be 1322–1344℃,and the high-temperature viscosity showed a decreasing trend with increasing Fe *** corrosion behavior of four types of CMAS-Fe to Gd_(2)Zr_(2)O_(7)coatings at 1350℃was *** the initial corrosion stage(0.1 h),anorthite was precipitated in CMAS-Fe with a high Ca:Si ratio,while Fe-garnet was formed in the melt with the highest Fe *** the corrosion time resulted in the formation of a reaction layer,which exhibited an interpenetrating network composed of Gd-oxyapatite,ZrO_(2),and residual *** spinel was precipitated within the reaction *** 1 h or even longer time,the reaction layers tended to be stable and compact,which had comparable hardness and fracture toughness to those of Gd_(2)Zr_(2)O_(7)*** the cyclic CMAS-Fe attack,the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration,resulting in the continuous growth of the reaction *** a result,the Gd_(2)Zr_(2)O_(7)coatings had a large consumption in the thickness,degrading the coating ***,the Gd_(2)Zr_(2)O_(7)coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.

关键词： thermal barrier coatings(TBCs) Gd_(2)Zr_(2)O_(7) Fe-containing CaO-MgO-Al2O3-SiO_(2)(CMAS) corrosion resistance reaction layer

Degradation analysis and doping modification optimization for high-voltage P-type layered cathode in sodium-ion batteries

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Journal of Energy Chemistry 2024年第2期89卷 1-9,I0002页

作者： bao Zhang Yi Zhao Minghuang Li Qi Wang lei Cheng lei Ming Xing Ou Xiaowei Wang National Engineering Laboratory for High-Efficiency Recovery of Refractory Nonferrous Metals School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083HunanChina Zhejiang Power New Energy Co. LTDZhuji 311800ZhejiangChina

Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage *** this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently *** this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox *** introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel *** Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 *** investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.

关键词： Soidum ion batteries Layer cathode materials P-type High-voltage performance Degradation analysis

Dynamic multifunctional metasurfaces:an inverse design deep learning approach

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Photonics Research 2024年第1期12卷 123-133页

作者： ZHI-DAN lei YI-DUO XU CHENG lei yan ZHAO DU WANG The Institute of Technological Sciences Wuhan UniversityWuhan 430072China College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Optical metasurfaces(OMs)offer unprecedented control over electromagnetic waves,enabling advanced optical *** emergence of deep learning has opened new avenues for designing ***,existing deep learning methods for OMs primarily focus on forward design,which limits their design capabilities,lacks global optimization,and relies on prior ***,most OMs are static,with fixed functionalities once *** overcome these limitations,we propose an inverse design deep learning method for dynamic *** approach comprises a forward prediction network and an inverse retrieval *** forward prediction network establishes a mapping between meta-unit structure parameters and reflectance *** inverse retrieval network generates a library of meta-unit structure parameters based on target requirements,enabling end-to-end design of *** incorporating the dynamic tunability of the phase change material Sb2Te3with inverse design deep learning,we achieve the design and verification of dynamic multifunctional *** results demonstrate OMs with multiple information channels and encryption capabilities that can realize multiple physical field optical modulation *** Sb2Te3is in the amorphous state,near-field nano-printing based on meta-unit amplitude modulation is achieved for X-polarized incident light,while holographic imaging based on meta-unit phase modulation is realized for circularly polarized *** the crystalline state,the encrypted information remains secure even with the correct polarization input,achieving double *** research points towards ultra-compact,high-capacity,and highly secure information storage approaches.

关键词： polarization inverse approach

Module Structures on U(ε^(-))for the Euclidean Algebra

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Algebra Colloquium 2024年第1期31卷 49-56页

作者： Yixin bao yan'an Cai School of Sciences Harbin Institute of Technology ShenzhenGuangdong 518055China Department of Mathematics Soochow University SuzhouJiangsu 215006China

We classify modules which are free of rank 1 when restricted to the negative part for the Euclidean Lie *** and necessary conditions for the simplicity of these modules are *** these modules we construct modules which... 详细信息

关键词： Euclidean algebra free module simple module nonweight module

An effective strategy of constructing multi-metallic oxides of ZnO/ CoNiO_(2)/CoO/C microflowers for improved supercapacitive performance

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Chinese Journal of Chemical Engineering 2024年第3期67卷 1-8页

作者： Wei Guo yan Zhang Xiaxin lei Shuang Wang College of Physics Taiyuan University of TechnologyJinzhong 030600China College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

In this work,a new ZnO/CoNiO_(2)/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N_(2) ***,the oxidation-defect annealing environment is conducive to both morphology and component of the composite,which flower-like ZnO/CoNiO_(2)/CoO/C is *** from good chemical stability of ZnO,high energy capacity of CoNiO_(2) and CoO and good conductivity of C,the as-prepared sample shows promising electrochemical behavior,including the specific capacity of 1435 C·g^(-1) at 1 A·g^(-1),capacity retention of 87.3%at 20 A·g^(-1),and cycling stability of 90.5%for 3000 cycles at 5 A·g^(-1),***,the prepared ZnO/CoNiO_(2)/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^(-1) at 850 W·kg^(-1).The results reflect that the as-prepared ZnO/CoNiO_(2)/CoO/C microflowers are considered as high performance electrode materials for supercapacitor,and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

关键词： Composites Electrochemistry Hydrothermal Transition metal oxides Structural control Supercapacitors

Electromagnetic characteristic analysis and design of a linear motor used for ultra-high-speed EMS maglev train

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Science China(Technological Sciences) 2024年第6期67卷 1957-1973页

作者： GAO Han SHI TingNa GAO XinMai lei yanXiao yan Dong GUO Liyan yan yan College of Electrical Engineering Zhejiang UniversityHangzhou310027China Zhejiang University Advanced Electrical Equipment Innovation Center Hangzhou311107China State Key Laboratory of High-speed Maglev Transportation Technology Qingdao266100China CRRC Qingdao Sifang Co.Ltd. Qingdao266111China

The operating speed of the commercial electromagnetic suspension(EMS)maglev train has been over 430 km/h,making it the fastest means of land *** the increasing demands of people traveling,it is necessary to further improve the operating speed of maglev *** to examine whether the existing EMS system can meet the requirements of ultra-highspeed operation(more than 600 km/h),the electromagnetic characteristics of an EMS linear motor under the operating speed of 600–1000 km/h fed by a square-wave voltage supply is investigated in this ***,an electromagnetic field model of the EMS system under the square-wave voltage supply is established to investigate its electromagnetic performance,e.g.,the characteristics of phase current,the magnetic flux density,and the electromagnetic ***,the relationship between the harmonic components of the air-gap magnetic flux density and electromagnetic force is investigated using the two-dimensional fast Fourier transform(2D-FFT)to reveal the mechanism of electromagnetic force ***,to address the issues of excessive armature current density and significant electromagnetic force ripple,the linear motor is re-designed by enlarging the stator slot area and reshaping the mover's main magnetic ***,the Taguchi method is used to further improve the electromagnetic characteristics of the linear electric ***,the effectiveness of the proposed optimal design is validated by the finite-element analysis(FEA)based co-simulation.

关键词： ultra-high-speed maglev transportation electromagnetic suspension(EMS) linear motor electromagnetic force ripple suppression