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Rare Metals 2024年第4期43卷 1702-1712页

作者： Xuan Liu Zi-Xia Lin Yin-Biao Shi Xiao-Yan Wang Ming-Ye Ding Xiao-Fei Yang college of science Nanjing Forestry University Testing Center Yangzhou University

Regulating luminescent dynamics of lanthanide-based luminescent materials via external stimuli is of great significance in the fields of optical thermometry and high-level anti-counterfeiting.However,it is still a huge challenge to realize multimodal emissions with tunable color outputs from a single activator in simple structures via smart dynamic control of photon transition processes.Herein,we present a mechanistic strategy to achieve multimodal luminescence of Er3+activators with color-switchable outputs in a non-core-shell host.Under the control of excitation dynamics(λex=980,808,1532,377 nm),the population among the intermediate en ergy levels of Er3+and the interaction between Er3+and Yb3+could be precisely modulated through energy transfer and migration processes,leading to the generation of colortunable multimodal luminescence upon diverse excitation modes（non-steady-state,single-/dual-wavelength steady,thermal activation）.Inspired by its special luminescent performance,the as-obtained material exhibits great potential in noncontact thermometry,multimodal anticounterfeiting,and high-capacity information encryption by performing a series of proof-of-concept experiments.Our findings might provide a conceptual model to modulate the luminescent dynamics in a simple-structured system for the generation of color-adjustable multimodal emissions,which is convenient for the development of advanced luminescent materials toward versatile cuttingedge applications.

关键词： Lanthanide ions Multimodal emission Upconversion Downshifting Anti-counterfeiting Luminescent thermometry

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 drop.Additional 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,respectively.The simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be reached.The 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 pressure.When 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,respectively.The 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

Bimagnetic metal constructed core-shell structure of Fe@Co nanowires for multi-band microwave absorption

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Progress in Natural science:Materials International 2024年第2期34卷 354-361页

作者： Ping-an Yang Rui Cai Haibo Ruan Nanqing Zhang Xin Huang Rui Li Yuxin Zhang Yi Lu Zhihao Zhou School of Automation Chongqing University of Posts and Telecommunications Chongqing Key Laboratory of Materials Surface & Interface science Chongqing University of Arts and Sciences college of Engineering and Technology Zunyi Normal College college of Material science and Engineering Chongqing University

Controlled fabrication of materials by surface modification techniques has been a hot research topic. In this paper,one-dimensional(1D) core-shell structure Fe@Co nanowires(NWs) were successfully prepared by anchoring 0-dimensional(0D) Co nanoparticles on 1D Fe NWs based on the in situ reduction method. The electromagnetic parameters of the specimens at a filler mass fraction of 25 wt% were tested and the microwave loss mechanism was deeply analyzed. Binary magnetic metals in a core-shell structure have excellent multi-band microwave absorption capability(S-band, X-band and Ku-band). This is due to the heterogeneous interface and magnetic coupling effects tuning the dielectric and magnetic loss. This study offers a workable plan for creating effective multi-band magnetic metal-based microwave absorbers.

关键词： Core-shell structure Interface Magnetic coupling Microwave absorption One-dimensional nanowires

Event-triggered distributed optimization for model-free multi-agent systems

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Frontiers of Information Technology & Electronic Engineering 2024年第2期25卷 214-224页

作者： Shanshan ZHENG Shuai LIU Licheng WANG college of science University of Shanghai for Science and TechnologyShanghai200093China college of Automation Engineering Shanghai University of Electric PowerShanghai200090China

In this paper,the distributed optimization problem is investigated for a class of general nonlinear model-free multi-agent systems.The dynamical model of each agent is unknown and only the input/output data are available.A model-free adaptive control method is employed,by which the original unknown nonlinear system is equivalently converted into a dynamic linearized model.An event-triggered consensus scheme is developed to guarantee that the consensus error of the outputs of all agents is convergent.Then,by means of the distributed gradient descent method,a novel event-triggered model-free adaptive distributed optimization algorithm is put forward.Sufficient conditions are established to ensure the consensus and optimality of the addressed system.Finally,simulation results are provided to validate the effectiveness of the proposed approach.

关键词： Distributed optimization Multi-agent systems Model-free adaptive control Event-triggered mechanism

ChatGPT is a Remarkable Tool—For Experts

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Data Intelligence 2024年第1期6卷 240-296页

作者： Amos Azaria Rina Azoulay Shulamit Reches School of Computer science Ariel UniversityIsrael Department of Computer science Jerusalem College of TechnologyIsrael Department of Mathematics Jerusalem College of TechnologyIsrael

This paper investigates the capabilities of ChatGPT as an automated assistant in diverse domains,including scientific writing,mathematics,education,programming,and healthcare.We explore the potential of ChatGPT to enhance productivity,streamline problem-solving processes,and improve writing style.Furthermore,we highlight the potential risks associated with excessive reliance on ChatGPT in these fields.These limitations encompass factors like incorrect and fictitious responses,inaccuracies in code,limited logical reasoning abilities,overconfidence,and critical ethical concerns of copyright and privacy violation.We outline areas and objectives where ChatGPT proves beneficial,applications where it should be used judiciously,and scenarios where its reliability may be limited.In light of observed limitations,and given that the tool's fundamental errors may pose a special challenge for non-experts,ChatGPT should be used with a strategic methodology.By drawing from comprehensive experimental studies,we offer methods and flowcharts for effectively using ChatGPT.Our recommendations emphasize iterative interaction with ChatGPT and independent verification of its outputs.Considering the importance of utilizing ChatGPT judiciously and with expertise,we recommend its usage for experts who are well-versed in the respective domains.

关键词： limitations utilizing Tool

Effect of kerosene injection states on mixing and combustion characteristics in a cavity-based supersonic combustor

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Chinese Journal of Aeronautics 2024年第4期37卷 308-320页

作者： Xu LIU Peibo LI Fei LI Hongbo WANG Mingbo SUN Chao WANG Yixin YANG Dapeng XIONG Yanan WANG science and Technology on Scramjet Laboratory College of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China

It has been found that the static pressure distribution along the axial direction of liquid kerosene is lower than that of the gaseous kerosene under the same flow condition and overall equivalent ratio from previous studies.To further investigate this phenomenon,a compressible two-phase parallel simulation method is utilized to analyze the mixing and combustion characteristics of gaseous and liquid kerosene jets in a cavity-based supersonic combustor.The numerical results are consistent with the experiments and demonstrate that gaseous injection leads to a cavity shear layer that dives deeper into the cavity,forming two recirculation zones in the front and rear of the cavity.In contrast,the cavity shear layer is closer to the mainstream during liquid injection,and only a large recirculation zone is formed in the rear of the cavity.As a result of the cavity shear layer and the recirculating flow,the fuel vapor of gaseous injection accumulates in the front of the cavity,while for the liquid injection,the fuel vapor disperses in the cavity,cavity shear layer,and the region above,and the rear of the cavity has a higher fuel vapor concentration than the front.This unique fuel distribution causes the combustion area to be concentrated in the cavity during the gaseous injection but dispersed inside and downstream of the cavity during the liquid injection.As a result,forming a thermal throat under the same conditions is more challenging during liquid injection,and the generated static pressure distribution is lower than that during the gaseous injection.

关键词： Gaseous injection Liquid injection Mixing process Combustion Supersonic flow

Defects and morphology engineering for constructing V_(5)-Ni_(3)S_(2)@Vs-Cu_(2)S nanotube heterojunction arrays toward efficient bifunctional electrocatalyst for overall water splitting

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Journal of Energy Chemistry 2024年第7期94卷 29-40页

作者： Wenyuan Sun Alan Meng Lei Wang Guicun Li Jinfeng Cui Yongkai Sun Zhenjiang Li college of Materials science and Engineering Qingdao University of Science and TechnologyQingdao 266042ShandongChina Key Laboratory of Optic-electric Sensing and Analytical Chemistryfor Life science MOE College of Chemistry and Molecular EngineeringQingdao Universityof Science and TechnologyQingdao 266042ShandongChina college of Environment and Safety Engineering Qingdao University of Science and TechnologyQingdao 266042ShandongChina Qingdao Huanghai University Qingdao 266000ShandongChina college of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao 266061ShandongChina

The development of highly active,stable and inexpensive electrocatalysts for hydrogen production by defects and morphology engineering remains a great challenge.Herein,S vacancies-rich Ni_(3)S_(2)@Cu_(2)S nan-otube heterojunction arrays were in-situ grown on copper foam(V_(5)-Ni_(3)S_(2)@Vs-Cu_(2)S NHAs/CF)for efficient electrocatalytic overall water splitting.With the merits of nanotube arrays and efficient electronic mod-ulation drived by the OD vacancy defect and 2D heterojunction defect,the resultant V_(5)-Ni_(3)S_(2)@Vs-Cu_(2)S NHAs/CF electrocatalyst exhibits excellent electrocatalytic activity with a low overpotential of 47 mV for the hydrogen evolution reaction(HER)at 10 mA cm^(-2) current density,and 263 mV for the oxygen evolution reaction(OER)at 50 mA cm^(-2) current density,as well as a cell voltage of 1.48 V at 10 mA cm^(-2).Moreover,the nanotube heterojunction arrays endows V_(5)-Ni_(3)S_(2)@Vs-Cu_(2)S NHAs/CF with outstanding stability in long-term catalytic processes,as confirmed by the continuous chronopotentiom-etry tests at current densities of 10 mA cm^(-2) for 100 h.

关键词： Nanotubearrays Heterojunction Vacancy Bifunctional electrocatalyst Overall water splitting

MOF-derived porous graphitic carbon with optimized plateau capacity and rate capability for high performance lithium-ion capacitors

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 395-404页

作者： Ge Chu Chaohui Wang Zhewei Yang Lin Qin Xin Fan college of Materials science&Engineering Guilin University of TechnologyGuilin 541004China Institute of Energy Innovation College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China

The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl solu-tion.The as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion storage.Additionally,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).

关键词： metal-organic framework porous graphitic carbon optimized plateau capacity kinetic analysis lithium-ion capacitor

The Effect of Key Nodes on theMalware Dynamics in the Industrial Control Network

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Computers, Materials & Continua 2024年第4期79卷 329-349页

作者： Qiang Fu JunWang Changfu Si Jiawei Liu college of Computer science and Technology Shenyang University of Chemical TechnologyShenyang110142China college of Computer science and Engineering Northeastern UniversityShenyang110169China

As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is becoming increasingly close,which leads to frequent security accidents.This paper proposes a model for the industrial control network.It includes a malware containment strategy that integrates intrusion detection,quarantine,and monitoring.Basedonthismodel,the role of keynodes in the spreadofmalware is studied,a comparisonexperiment is conducted to validate the impact of the containment strategy.In addition,the dynamic behavior of the model is analyzed,the basic reproduction number is computed,and the disease-free and endemic equilibrium of the model is also obtained by the basic reproduction number.Moreover,through simulation experiments,the effectiveness of the containment strategy is validated,the influence of the relevant parameters is analyzed,and the containment strategy is optimized.In otherwords,selective immunity to key nodes can effectively suppress the spread ofmalware andmaintain the stability of industrial control systems.The earlier the immunization of key nodes,the better.Once the time exceeds the threshold,immunizing key nodes is almost ineffective.The analysis provides a better way to contain the malware in the industrial control network.

关键词： Key nodes dynamic model industrial control network simulation

Computing large deviation prefactors of stochastic dynamical systems based on machine learning

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Chinese Physics B 2024年第4期33卷 364-373页

作者：李扬袁胜兰陆凌宏志刘先斌 School of Automation Nanjing University of Science and TechnologyNanjing 210094China Department of Mathematics School of SciencesGreat Bay UniversityDongguan 523000China Center for mathematical sciences Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Mechanics and Control for Aerospace Structures College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

We present a large deviation theory that characterizes the exponential estimate for rare events in stochastic dynamical systems in the limit of weak noise.We aim to consider a next-to-leading-order approximation for more accurate calculation of the mean exit time by computing large deviation prefactors with the aid of machine learning.More specifically,we design a neural network framework to compute quasipotential,most probable paths and prefactors based on the orthogonal decomposition of a vector field.We corroborate the higher effectiveness and accuracy of our algorithm with two toy models.Numerical experiments demonstrate its powerful functionality in exploring the internal mechanism of rare events triggered by weak random fluctuations.

关键词： machine learning large deviation prefactors stochastic dynamical systems rare events