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Neural-network-based fully distributed formation control for nonlinear multi-agent systems with event-triggered communication

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Science China(Technological Sciences) 2024年第1期67卷 209-220页

作者： ZHU guoliang lIU KeXin gu HaiBo lÜjinHu School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Zhongguancun laboratory Beijing 100094China

This paper investigates the consensus-based formation control problem for multi-agent systems with unknown nonlinear *** achieve the desired formation,we propose two formation controllers to achieve the desired formation,one based on system states and the other on system *** proposed controllers utilize adaptive gains to avoid global information and neural networks to estimate and compensate for *** proposed event-triggered schemes avoid continuous communication among agents and exclude the Zeno *** analysis reveals that formation errors are bounded,and numerical simulations are used to validate the effectiveness of the proposed approaches.

关键词： formation control neural network adaptive control event-triggered communication multi-agent systems

The Inherent law of the Unpredictability of Financial Asset Price Fluctuations: Multistability and Chaos

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journal of Systems Science & Complexity 2024年第2期37卷 776-804页

作者： gu Enguo Huanghe University of Science and Technology Zhengzhou 450006China

This paper aims at understanding the price dynamics generated by the interaction of traders relying on heterogeneous expectations in an asset pricing *** the present work the authors analyze a financial market populated by five types of boundedly rational speculators-two types of fundamentalists,two types of chartists and trend followers which submit buying/selling orders according to different trading *** authors formulate a stock market model represented as a 2 dimensional piecewise linear discontinuous *** proposed contribution to the existing financial literature is two ***,the authors perform study of the model involving a 2 dimensional piecewise linear discontinuous map through a combination of qualitative and quantitative *** authors focus on the existence conditions of chaos and the multi-stability regions in parameter *** border collision bifurcation curves and basins of multi-attractors are also *** authors find that chaos or quasi-period exists only in the case of fixed point being a saddle(regular or flip)and that the coexistence of multiple attractors may exist when the fixed point is an attractor,but it is common for spiral and flip fixed points.

关键词： BCB curve chaos financial market heterogeneous agents multiple attractors piecewise linear discontinuous map

Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： Y.H.Zhang H.li Z.w.Yang X.liu Q.F.gu State Key laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.with increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

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

Ultra-simplified diffraction-based computational spectrometer

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light(Science & Applications) 2024年第6期13卷 1022-1031页

作者： Chuangchuang Chen Honggang gu Shiyuan liu State Key laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhanHubei430074China Optics Valley laboratory WuhanHubei430074China

Miniaturizing spectrometers for compact and cost-effective mobile platforms is a major challenge in current spectroscopy research,where conventional spectrometers are impractical due to their bulky *** miniaturized designs primarily rely on precalibrated response functions of nanophotonic structures to encode spectral information captured in a snapshot by detector *** spectrum reconstruction is achieved through computational techniques,but this requires precise component design,high-precision fabrication,and *** propose an ultra-simplified computational spectrometer that employs a one-to-broadband diffraction decomposition strategy facilitated by a numerical regularized transform that depends only on the spectrum of the diffracted *** key feature of our design is the use of a simple,arbitrarily shaped pinhole as the partial disperser,eliminating the need for complex encoding designs and full spectrum *** spectrometer achieves a reconstructed spectral peak location accuracy of better than 1 nm over a 200 nm bandwidth and excellent resolution for peaks separated by 3 nm in a bimodal spectrum,all within a compact footprint of under half an ***,our approach also reveals a breakthrough in broadband coherent diffractive imaging without requiring any prior knowledge of the broadband illumination spectrum,assumptions of non-dispersive specimens,or correction for detector quantum efficiency.

关键词： simplified spectrum illumination

An internal ballistic model of electromagnetic railgun based on PFN coupled with multi-physical field and experimental validation

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Defence Technology（防务技术） 2024年第2期32卷 254-261页

作者： Benfeng gu Haiyuan li Baoming li National Key laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China

To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore *** this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried *** test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of *** the simulation results and experimental data,the damage condition of the contact surface is analyzed.

关键词： Internal ballistic modeling Electromagnetic rail gun Multi-physics field coupling Experimental validation PFN

Prediction of liquid circulation flow rate in RH degasser:improvement of decarburization at low atmospheric pressure

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journal of Iron and Steel Research International 2024年第7期31卷 1661-1667页

The two-fluid model coupled with population balance model was used for simulating the gas-liquid flow in the Ruhrstahl-Heraeus(RH)*** predicted circulation flow rate was compared with that measured from a water model experiment to validate the mathematical ***,influence of snorkel immersion depth on liquid circulation flow rate was numerically investigated under an atmospheric pressure of 101 and 84 kPa,*** result indicates that the circulation flow rate of the RH degasser in the high-altitude area was severely reduced because of the decrease in atmospheric ***,increasing the snorkel immersion depth from 0.5 to 0.7 m can compensate for the decrease in atmospheric *** test result indicates that decarburization rate is significantly enhanced by increasing the snorkel immersion *** optimization,the percentage of heats with a final carbon content less than 0.002 wt.%is significantly increased from 22.0%to 96.4%.

关键词： RH degasser Two-fluid model Population balance model-Circulation flow rate Decarburization Snorkel immersion depth

A Comparison of Four Neural Networks Algorithms on locomotion Intention Recognition of lower limb Exoskeleton Based on Multi-source Information

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journal of Bionic Engineering 2024年第1期21卷 224-235页

作者： Duojin wang Xiaoping gu Hongliu Yu Institute of Rehabilitation Engineering and Technology University of Shanghai for Science and Technology516 Jungong RoadShanghai 200093China Shanghai Engineering Research Center of Assistive Devices 516 Jungong RoadShanghai 200093China

lower limb Exoskeletons(llEs)are receiving increasing attention for supporting activities of daily *** such active systems,an intelligent controller may be *** this paper,we proposed a locomotion intention recognition system based on time series data sets derived from human motion *** of input data and Deep learning(Dl)algorithms,this framework enables the detection and prediction of users’movement *** makes it possible to predict the detection of locomotion modes,allowing the llEs to provide smooth and seamless *** pre-processed eight subjects were used as input to classify four scenes:Standing/walking on level Ground(S/wOlG),Up the Stairs(US),Down the Stairs(DS),and walking on Grass(wOG).The result showed that the ResNet performed optimally compared to four algorithms(CNN,CNN-lSTM,ResNet,and ResNet-Att)with an approximate evaluation indicator of 100%.It is expected that the proposed locomotion intention system will significantly improve the safety and the effectiveness of llE due to its high accuracy and predictive performance.

关键词： lower limb exoskeletons(llEs) locomotion intention ResNet Multi-source

Evaluating the historical,clinical,and cultural value of the Tian Hui Yi jian

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journal of Traditional Chinese Medicine 2024年第1期44卷 220-221页

作者： YU linyong gu Man China Academy of Chinese Medical Sciences Beijing 100700China Institute for History of Medicine and Medical literature China Academy of Chinese Medical SciencesBeijing 100700China

Tian Hui Yi jian was compiled by the Tianhui Medical Manuscripts Compilation Group,which includes scholars from the Institute for History of Medicine and Medical literature of the China Academy of Chinese Medical Sciences(CACMS),Chengdu University of Traditional Chinese Medicine,Chengdu Institute of Cultural Relics and Archaeology,and jingzhou Cultural Relics Protection *** was published by the Cultural Relics Press in November *** volume includes images of eight medical manuscripts,along with the Team's annotations,and photographs of a lacquered figurine with meridian-channels and words on its surface.

关键词： surface Chengdu Tian