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Amphiphilic amino-acid derivatives promote gram-scale single-crystal COFs synthesis

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Science China Chemistry 2024年第2期67卷 415-416页

作者： Yijia Yuan Kian ping Loh Department of Chemistry National University of SingaporeSingapore117543Singapore

Covalent organic frameworks(COFs) are crystalline organic compounds synthesized from covalently linked building blocks that extend in space to form a framework structure with periodic pores. The covalent linkages used... 详细信息

关键词： synthesis correction reversible

A Fuzzy Trust Management Mechanism with Dynamic Behavior Monitoring for Wireless Sensor Networks

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China Communications 2024年第5期21卷 177-189页

作者： Fu Shiming Zhang ping Shi Xuehong School of Artificial Intelligence Chongqing University of EducationChongqing 400065China School of Communications and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China

Traditional wireless sensor networks(WSNs)are typically deployed in remote and hostile environments for information *** wireless communication methods adopted by sensor nodes may make the network highly vulnerable to various *** encryption and authentication mechanisms cannot prevent attacks launched by internal malicious *** trust-based security mechanism is usually adopted to solve this problem in ***,the behavioral evidence used for trust estimation presents some uncertainties due to the open wireless medium and the inexpensive sensor ***,how to efficiently collect behavioral evidences are rarely *** address these issues,in this paper,we present a trust management mechanism based on fuzzy logic and a cloud ***,a type-II fuzzy logic system is used to preprocess the behavioral evidences and alleviate ***,the cloud model is introduced to estimate the trust values for sensor ***,a dynamic behavior monitoring protocol is proposed to provide a balance between energy conservation and safety *** results demonstrate that our trust management mechanism can effectively protect the network from internal malicious attacks while enhancing the energy efficiency of behavior monitoring.

关键词： behavior monitoring cloud fuzzy trust wireless sensor networks

Understanding the Low Predictability of the 2015/16 El Niño Event Based on a Deep Learning Model

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Advances in Atmospheric Sciences 2024年第7期41卷 1313-1325页

作者： Tingyu WANG ping HUANG Xianke YANG Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China National Space Science Center Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Plant Science and Technology Huazhong Agricultural UniversityWuhan 430070China

The 2015/16 El Niño event ranks among the top three of the last 100 years in terms of intensity,but most dynamical models had a relatively low prediction skill for this event before the summer ***,the attribution of this particular event can help us to understand the cause of super El Niño–Southern Oscillation events and how to forecast them *** present study applies attribute methods based on a deep learning model to study the key factors related to the formation of this event.A deep learning model is trained using historical simulations from 21 CMIP6 models to predict the Niño-3.4 *** integrated gradient method is then used to identify the key signals in the North Pacific that determine the evolution of the Niño-3.4 *** crucial signals are then masked in the initial conditions to verify their roles in the *** addition to confirming the key signals inducing the super El Niño event revealed in previous attribution studies,we identify the combined contribution of the tropical North Atlantic and the South Pacific oceans to the evolution and intensity of this event,emphasizing the crucial role of the interactions among them and the North *** approach is also applied to other El Niño events,revealing several new precursor *** study suggests that the deep learning method is useful in attributing the key factors inducing extreme tropical climate events.

关键词： ENSO attribution deep learning ENSO prediction extreme El Niño

An adaptive energy regulation in a memristive map linearized from a circuit with two memristive channels

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Communications in Theoretical Physics 2024年第3期76卷 42-50页

作者： Feifei Yang ping Zhou Jun Ma School of Science Chongqing University of Posts and TelecommunicationsChongqing 430065China College of Electrical and Information Engineering Lanzhou University of TechnologyLanzhou 730050China Department of Physics Lanzhou University of TechnologyLanzhou 730050China

Nonlinear circuits can show multistability when a magnetic flux-dependent memristor(MFDM) or a charge-sensitive memristor(CSM) is incorporated into a one branch circuit,which helps estimate magnetic or electric field *** this paper,two different kinds of memristors are incorporated into two branch circuits composed of a capacitor and a nonlinear resistor,thus a memristive circuit with double memristive channels is *** circuit equations are presented,and the dynamics in this oscillator with two memristive terms are ***,the memristive oscillator is converted into a memristive map by applying linear transformation on the sampled time series for the memristive *** Hamilton energy function for the memristive oscillator is obtained by using the Helmholtz theorem,and it can be mapped from the field energy of the memristive *** energy function for the dual memristive map is suggested by imposing suitable weights on the discrete energy *** dynamical behaviors of the new memristive map are investigated,and an adaptive law is proposed to regulate the firing mode in the memristive *** work will provide a theoretical basis and experimental guidance for oscillator-to-map transformation and discrete map energy calculation.

关键词： Hamilton energy dual memristive map adaptive energy regulation

Volume of fluid simulation of single argon bubble dynamics in liquid steel under RH vacuum conditions

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Journal of Iron and Steel Research(International) 2024年第4期31卷 828-837页

作者： Gu-jun Chen Sheng-ping He College of Materials Science and Engineering Yangtze Normal UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Single argon bubble dynamics in liquid steel under Ruhrstahl-Heraeus(RH)vacuum conditions were simulated using the volume of fluid method,and the ideal gas law was used to consider bubble growth due to heat transfer and pressure *** simulation with a constant bubble density was also performed to validate the numerical method,and the predicted terminal bubble shape and velocity were found to agree with those presented in the Grace diagram and calculated by drag correlation,*** simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be *** primary bubble growth occurs within a rising distance of 0.3 m owing to heating by the high-temperature liquid steel;subsequently,the bubble continues to grow under equilibrium with the hydrostatic *** the initial diameter is 8-32 mm,the bubble diameter and rising velocity near the liquid surface are 80-200 mm and 0.5-0.8 m/s,*** bubble rises rectilinearly with an axisymmetric shape,and the shape evolution history includes an initial sphere,(dimpled)ellipsoid,and spherical cap with satellite bubbles.

关键词： Bubble dynamics Liquid steel Volume of fluid Bubble growth Bubble shape Rising velocity

Plastic deformation behavior of a Cu-10Ta alloy under strong impact loading

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Defence Technology（防务技术） 2024年第2期32卷 368-382页

作者： ping Song Jianghai Liu Wenbin Li Yiming Li Research Institute of Chemical Defense Academy of Military ScienceBeijing102205China Ministerial Key Laboratory of ZNDY Nanjing University of Science and TechnologyNanjing210094China

In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy *** properties of the alloy,including density,microstructure,melting point,and constant-volume specific heat,are *** the split Hopkinson pressure bar(SHPB)and flyerplate impact experiments,the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823 K and under strain rates of 1×10^(-3)-5.2×10^(3)s^(-1),and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108-942 m/s is *** of the Cu-10Ta microstructure that occurs during high-strain-rate impact is *** indicate that the Cu-10Ta alloy possesses good thermal stability,and at ambient temperatures of up to 50%its melting point,stress softening of less than 15%of the initial strength is observed.A modified J-C constitutive model is employed to accurately predict the variation of yield strength with strain *** strong impact,the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy,while significant deformation of the high-strength tantalum particles is less ***,the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong *** reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure.

关键词： Cu-10Ta SHPB Plastic deformation Flyer impact Hugoniot relationship

Multi-physics multi-scale simulation of unique equiaxed-to-columnar-to-equiaxed transition during the whole solidification process of Al-Li alloy laser welding

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Journal of Materials Science & Technology 2024年第4期171卷 235-251页

作者： Chu Han ping Jiang Shaoning Geng Liangyuan Ren School of Mechanical Science and Engineering Huazhong University of Science&Technology(HUST)Wuhan430074China

In this study,a novel multi-physics multi-scale model with the dilute multicomponent phase-field method in three-dimensional(3D)space was developed to investigate the complex microstructure evolu-tion in the molten pool during laser welding of Al-Li *** accurately compute mass data within both two and three-dimensional computational domains,three efficient computing methods,including central processing unit parallel computing,adaptive mesh refinement,and moving-frame algorithm,were *** was placed on the distinctive equiaxed-to-columnar-to-equiaxed transition phenomenon that occurs during the entire solidification process of Al-Li alloy laser *** results indi-cated that the growth distance of columnar grains that epitaxially grew from the base metal(BM)de-creased as the nucleation rate *** the nucleation rate increased,the morphology of the newly formed grains near the fusion boundary(FB)changed from columnar to equiaxed,and newly formed equiaxed grains changed from having high-order dendrites to no obvious dendrite *** the nucleation rate was sufficiently high,non-dendritic equiaxed grains could directly form near the FB,and there was nearly no epitaxial growth from the ***,simulation results illustrated the com-petition among multiple grains with varying orientations that grow in 3D space near the ***,how equiaxed grain bands develop was *** equiaxed band not only hindered the growth of early columnar grains but also some of its grains could grow epitaxially to form new columnar *** predicted results were in good agreement with experimental measurements and observations.

关键词： Laser welding Al-Li alloy Equiaxed-to-columnar-to-equiaxed transition Multi-physics multi-scale model Multicomponent alloys 3D phase-field model

Preparation of maximally-entangled states with multiple cat-state qutrits in circuit QED

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Frontiers of physics 2024年第3期19卷 239-251页

作者： Chui-ping Yang Jia-Heng Ni Liang Bin Yu Zhang Yang Yu Qi-ping Su Department of Physics Hangzhou Normal UniversityHangzhou 311121China School of Physics Nanjing UniversityNanjing 210093China Institute for Quantum Science and Technology University of CalgaryAlberta T2N 1N4Canada

In recent years,cat-state encoding and high-dimensional entanglement have attracted much ***,previous works are limited to generation of entangled states of cat-state qubits(two-dimensional entanglement with cat-state encoding),while how to prepare entangled states of cat-state qutrits or qudits(high-dimensional entanglement with cat-state encoding)has not been *** here propose to generate a maximally-entangled state of multiple cat-state qutrits(three-dimensional entanglement by cat-state encoding)in circuit *** entangled state is prepared with multiple microwave cavities coupled to a superconducting flux ququart(a four-level quantum system).This proposal operates essentially by the cavity-qutrit dispersive *** circuit hardware resource is minimized because only a coupler ququart is *** higher intermediate level of the ququart is occupied only for a short time,thereby decoherence from this level is greatly suppressed during the state ***,the state preparation time does not depend on the number of the qutrits,thus it does not increase with the number of the *** an example,our numerical simulations demonstrate that,with the present circuit QED technology,the high-fidelity preparation is feasible for a maximally-entangled state of two cat-state ***,we numerically analyze the effect of the inter-cavity crosstalk on the scalability of this *** proposal is universal and can be extended to accomplish the same task with multiple microwave or optical cavities coupled to a natural or artificial four-level atom.

关键词： maximally-entangled states cat state qutrit circuit QED

Nondegenerate Soliton Solutions of(2+1)-Dimensional Multi-Component Maccari System

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Chinese Physics Letters 2024年第6期41卷 11-17页

作者：孟勇方乒乒林机 Department of Physics Zhejiang Normal UniversityJinhua 321004China

For a multi-component Maccari system with two spatial dimensions,nondegenerate one-soliton and two-soliton solutions are obtained with the bilinear *** can be seen by drawing the spatial graphs of nondegenerate solitons that the real component of the system shows a cross-shaped structure,while the two solitons of the complex component show a multi-solitoff *** the same time,the asymptotic analysis of the interaction behavior of the two solitons is conducted,and it is found that under partially nondegenerate conditions,the real and complex components of the system experience elastic collision and inelastic collision,respectively.

关键词： structure. degenerate soliton