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Pr-Tb synergistic strengthening on coercivity of Nd-Ce-Fe-B magnets grain boundary diffused with Pr-Tb-Al-Ga alloys

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Journal of Rare Earths 2024年第9期42卷 1704-1709,I0003页

作者： Ruifang Song Hang zhao Haibo Feng Institute of Functional Materials Central Iron&Steel Research InstituteBeijing100081China

Sintered Nd-Ce-Fe-B magnets were grain boundary diffused(GBDed) with Pr_(x)Tb_(80-x)Al_(10)Ga_(10)(at%)(x=0,20,40,60,80) *** effect of Pr/Tb content in diffusion source on magnetic properties,microstructure and elements distribution of GBDed magnets was *** Pr is used to substitute for 75% Tb in diffusion source,Tb consumption per unit coercivity improvement of GBDed magnet reduces by 77%,compared with the Tb_(80)Al_(10)Ga_(10) diffused *** element diffuses into magnets and then forms Tb-rich shell with high magneto-crystalline anisotropy field surrounding main phase grains,resulting in substantial coercivity *** with low melting point diffuses deeply along liquid grain boundary phase during GBD *** can eliminate some sharp defects of main phase grains and make grain boundaries smooth,which provides diffusion channels for further diffusion of Tb ***,there are more diffusion channels for Tb and less Tb enriched at surface region,making Tb diffuse more deeply and improving Tb utilization *** method significantly improves the coercivity,and realizes the green,efficient and high-quality utilization of heavy rare earth(HRE)elements.

关键词： Grain boundary diffusion Rare earths Microstructure Synergistic strengthening

Study on macro and micro shear strength of continuously graded and gap-graded sand

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Particuology 2024年第3期86卷 101-116页

作者： Peiran zhao Songyu Liu Kai Wu School of Transportation Southeast UniversityNanjing210096China

The particle gradation of sand has a significant influence on its shear strength,yet the similarities and differences between the effects of continuous and gap grading have yet to be fully *** this study,the discrete element method(DEM)was used to simulate biaxial tests on granular samples that were both continuously graded and *** macroscopic analysis revealed that the shear strength of continuously graded sands increases initially and then decreases as the uniformity of particle size distribution *** the other hand,the lack of medium particles in gap-graded sands amplifies the difference in particle size between coarse and fine particles,leading to a decrease in shear ***,both continuous and gap gradings affect the internal packing structure of the particle assembly,which consequently affects particle stress distributions,contact forces,coordination numbers,stress-induced anisotropies,and contact force networks,thus having an impact on the macroscopic shear *** global uniformity of particle size distribution was unidirectionally affected by continuous grading,while gap grading had a locally bidirectional *** findings provide a better understanding of the effects of particle grading on the macroscopic shear strength of sands.

关键词： Biaxial test Shear strength Particle gradation Discrete element method Micromechanics

Theoretical Design of Defects as a Driving Force for Ion Transport in Li3OBr Solid Electrolyte

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Energy & Environmental Materials 2024年第3期7卷 147-157页

作者： Xingyun Luo Yanlu Li Xian zhao State Key Lab of Crystal Materials and Institute of Crystal Materials Shandong University Center for Optics Research and Engineering Shandong University

Due to ever-increasing concerns about safety issues in using Li ionic batteries,solid electrolytes have extensively *** Li-rich antiperovskite Li3OBr has been considered as a promising solid electrolyte candidate,but it still suffers challenges to achieve a high ionic conductivity owing to the high intrinsic symmetry of the crystal ***,we presented a design strategy that introduces various point defects and grain boundaries to break the high lattice symmetry of Li3OBr crystal,and their effect and microscopic mechanism of promoting the migration of Li-ion were explored *** has been found that Liiare the dominant defects responsible for the fast Li-ion diffusion in bulk Li3OBr and its surface,but they are easily trapped by the grain boundaries,leading to the annihilating of the Frenkel defect pair V'Li+Li,and thus limits the V'Lidiffusion at the grain *** VBrdefect near the grain boundaries can effectively drive V'Liacross the grain boundary,thereby converting the carrier of Li+migration from Li,in the bulk and surface to V'Liat the grain boundary,and thus improving the ionic conductivity in the whole Li3OBr *** work provides a comprehensive insight into the Li+transport and conduction mechanism in the Li3OBr *** opens a new way of improving the conductivity for all-solid-state Li electrolyte material through the defect design.

关键词： defects density functional theory ionic migration solid electrolyte

Highlights of mainstream solar cell efficiencies in 2023

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Frontiers in Energy 2024年第1期18卷 8-15页

作者： Wenzhong SHEN Yixin zhao Feng LIU Institute of Solar Energy and Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education)School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China School of Environmental Science and Engineering and Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Chemical Engineering and Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China

This article continues our highlights last two years[1,2]on the highest independently confirmed mainstream(silicon,perovskite,and organic)solar cell efficiencies in *** world record power conversion efficiency(PCE)of the single-junction silicon and perovskite/silicon tandem solar cells has reached over 27%and close to 34%,respectively,in *** have also witnessed the rapid mass-production development of the silicon passivating contact and silicon back contact solar cells,as well as further progress with perovskite solar cells(PSCs).

关键词： perovskite mainstream fir

Event-triggered distributed cross-dimensional formation control for heterogeneous multi-agent systems

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Frontiers of Information Technology & Electronic Engineering 2024年第8期25卷 1123-1133页

作者： Huimin WEI Chen PENG Min zhao School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444China School of Mathematics and Statistics Nantong UniversityNantong 226019China

This paper concerns the event-triggered distributed cross-dimensional formation control problem of heterogeneous multi-agent systems(HMASs)subject to limited network *** central aim is to design an effective distributed formation control scheme that will achieve the desired formation control objectives even in the presence of restricted ***,a multi-dimensional HMAS is first developed,where a group of agents are assigned to several subgroups based on their ***,to mitigate the excessive consumption of communication resources,a cross-dimensional event-triggered communication mechanism is designed to reduce the information interaction among agents with different *** the proposed event-based communication mechanism,the problem of HMAS cross-dimensional formation control is transformed into the asymptotic stability problem of a closed-loop error ***,several stability criteria for designing a cross-dimensional formation control protocol and communication schedule are presented in an environment where there is no information interaction among follower ***,a simulation case study is provided to validate the effectiveness of the proposed formation control protocol.

关键词： Heterogeneous multi-agent systems Formation control Cross-dimensional event-triggered mechanism

Study on a semi-resolved CFD-DEM method for rod-like particles in a gas-solid fluidized bed

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Particuology 2024年第4期87卷 20-36页

作者： Liping He Zhengxian Liu Yongzhi zhao Department of Mechanics School of Mechanical EngineeringTianjin UniversityTianjin300350China Insttute of Process quipment College of Energy EngineeringZhejiang UniversityHangzhou30027China

Based on a semi-resolved CFD-DEM coupling method,this study proposed a method that uses the minimum distance between the fluid grid and the particle boundary as a reference value to determine the degree of influence of the target fluid grid on the particle's drag force.A fluidized bed of rod-like particles was chosen as a typical case to investigate the effect of different fluid grid scales on various fluidized bed characteristic *** calculation performance of the semi-resolved and unre-solved CFD-DEM coupling algorithm on key fluidized bed characteristic parameters such as average pressure drop,particle frequency distribution with bed height,and particle orientation distribution were *** was found that the semi-resolved CFD-DEM coupling algorithm gradually obtained results with higher consistency with decreasing fluid grid scale for key parameters such as particle frequency distribution with bed height,particle orientation distribution,and time-history mixing index,exhibiting a phenomenon similar to grid independence in fluid *** comparing with experimental results,it was verified that the semi-resolved CFD-DEM coupling algorithm can be applied to simulate multi-granular gas-solid systems with fluid grid scales equivalent to particle *** algorithm solves the limitation of fluid grid scale in the unresolved CFD-DEM coupling framework and improves the grid adaptability of the CFD-DEM coupling simulation algorithm.

关键词： CFD-DEM Semi-resolved method Fluid-solid flow Non-spherical particle Fluidized bed

Recent progress in lanthanide ions doped inorganic metal halide perovskites

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Journal of Rare Earths 2024年第2期42卷 237-250,I0001页

作者： Yiyan Zhang Tianyu zhao Guanying Chen MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringState Key Laboratory of Urban Water Resource and EnvironmentKey Laboratory of Micro-systems and Micro-structuresMinistry of EducationHarbin Institute of TechnologyHarbin150001China

Benefiting from their large molar extinction coefficient,high carrier mobility,narrow and tunable emissions,inorganic metal halide perovskites(IMHPs) demonstrate great potential in various optoelectrical devices including solar cells,light emitting diodes and photodetectors in the past few *** ions doping,well-known as a modification method of semiconductors,has been extensively applied in IMHPs as *** metal ions have been doped in IMHPs including alkali metals,alkali earth metals,transition metals and lanthanide metals,which either improve their optical performances or induce intriguing brand-new *** them,lanthanide metals feature plentiful energy levels and stable optical properties and are one of the most noteworthy *** we review recent progress in lanthanide ions doped *** summarize Yb,Eu or Er ions singly doping in detail,which was the most investigated species in *** lanthanide ions are also reviewed ***,we introduce lanthanide ions multi-doped IMHPs and at last we put forward several potential development *** the interests in lanthanide ions doped IMHPs rise,researchers have made some achievements in the *** though,there are more unexplored *** there are review articles focusing on metal ions doped IMHPs or lanthanide ions doped perovskites,this review aims to provide an overall introduction of lanthanide ions doped *** review may help researchers learn about lanthanide ions doped IMHPs and is to inspire researchers to make further promotion in this field.

关键词： Halide perovskite Lanthanide Doping Rare earths

TendiffPure:a convolutional tensor-train denoising diffusion model for purification

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Frontiers of Information Technology & Electronic Engineering 2024年第1期25卷 160-169页

作者： Mingyuan BAI Derun ZHOU Qibin zhao RIKEN AIP Tokyo 1030027Japan School of Environment and Society Tokyo Institute of TechnologyTokyo 1528550Japan

Diffusion models are effective purification methods,where the noises or adversarial attacks are removed using generative approaches before pre-existing classifiers conducting classification ***,the efficiency of diffusion models is still a concern,and existing solutions are based on knowledge distillation which can jeopardize the generation quality because of the small number of generation ***,we propose TendiffPure as a tensorized and compressed diffusion model for *** the knowledge distillation methods,we directly compress U-Nets as backbones of diffusion models using tensor-train decomposition,which reduces the number of parameters and captures more spatial information in multi-dimensional data such as *** space complexity is reduced from O(N^(2))to O(NR^(2))with R≤4 as the tensor-train rank and N as the number of *** results show that TendiffPure can more efficiently obtain high-quality purification results and outperforms the baseline purification methods on CIFAR-10,Fashion-MNIST,and MNIST datasets for two noises and one adversarial attack.

关键词： Diffusion models Tensor decomposition Image denoising

General Mean-Field BDSDEs with Continuous and Stochastic Linear Growth Coefficients

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Journal of Systems Science & Complexity 2024年第5期37卷 1887-1906页

作者： WANG Jinghan SHI Yufeng zhao Nana Institute for Financial Studies Shandong University Zhiyuan School of Liberal Arts Beijing Institute of Petrochemical Technology

In this paper, the authors study a class of general mean-field BDSDEs whose coefficients satisfy some stochastic conditions. Specifically, the authors prove the existence and uniqueness theorem of solution under stochastic Lipschitz condition and obtain the related comparison theorem. Besides,the authors further relax the conditions and deduce the existence theorem of solutions under stochastic linear growth and continuous conditions, and the authors also prove the associated comparison ***, an asset pricing problem is discussed, which demonstrates the application of the general mean-field BDSDEs in finance.

关键词： Backward doubly stochastic differential equations comparison theorem mean-field stochastic conditions Wasserstein metric