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Inter-well internal resonance analysis of rectangular asymmetric cross-ply bistable composite laminated cantilever shell under transverse foundation excitation

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1353-1370页

作者： Lele REN wei zhang Yufei zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanics Guangxi UniversityNanning 530004China Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical EngineeringBeijing University of TechnologyBeijing 100124China

The chaotic dynamic snap-through and complex nonlinear vibrations are investigated in a rectangular asymmetric cross-ply bistable composite laminated cantilever shell,in cases of 1:2 inter-well internal resonance and primary *** transverse foundation excitation is applied to the fixed end of the structure,and the other end is in a free *** first-order approximate multiple scales method is employed to perform the perturbation analysis on the dimensionless two-degree-of-freedom ordinary differential motion control *** four-dimensional averaged equations are derived in both polar and rectangular coordinate *** from the obtained frequency-amplitude and force-amplitude response curves,a detailed analysis is conducted to examine the impacts of excitation amplitude,damping coefficient,and tuning parameter on the nonlinear internal resonance characteristics of the *** nonlinear softening characteristic is exhibited in the upper stable-state,while the lower stable-state demonstrates the softening and linearity *** simulation is carried out using the fourth-order Runge-Kutta method,and a series of nonlinear response curves are *** the excitation amplitude further elucidates the global bifurcation and chaotic dynamic snap-through characteristics of the bistable cantilever shell.

关键词： bistable composite laminated cantilever shell inter-well internal resonance primary resonance chaotic dynamic snap-through complex nonlinear vibration

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Vertical vibration control using nonlinear energy sink with inertial amplifier

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Applied Mathematics and Mechanics(English Edition) 2023年第10期44卷 1721-1738页

作者： weixing zhang wei zhang Xiangying GUO Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures Beijing 100124China

To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper constructs pure nonlinear stiffness without neglecting the gravity effect of the oscillator. Both analytical and numerical methods are used to evaluate the performance of the NES-IA. The research findings indicate that even if the actual mass is 1% of the main oscillator, the NES-IA with proper inertia angles and mass distribution ratios can still effectively attenuate the steady-state and transient responses of the main oscillator. Nonlinear stiffness and damping also have important effects. Due to strongly nonlinear factors, the coupled system may exhibit higher branch responses under harmonic excitation. In shock excitation environment, the NES-IA with a large dynamic mass can trigger energy capture of both main resonance and high-frequency resonance. Furthermore, the comparison with the traditional NES also confirms the advantages of the NES-IA in overcoming mass dependence.

关键词： nonlinear energy sink(NES) vibration reduction inertial amplifier(IA) higher branch response high-frequency resonance

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CONVERGENCE AND STABILITY OF THE SPLIT-STEP THETA METHOD FOR A CLASS OF STOCHASTIC VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS DRIVEN BY LEVY NOISE

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Journal of Computational Mathematics 2024年第6期42卷 1688-1713页

作者： wei zhang School of Mathematical Sciences Heilongjiang UniversityHarbinChina

In this paper,we investigate the theoretical and numerical analysis of the stochastic Volterra integro-differential equations(SVIDEs)driven by L´evy *** existence,uniqueness,boundedness and mean square exponential stability of the analytic solutions for SVIDEs driven by L´evy noise are *** split-step theta method of SVIDEs driven by L´evy noise is *** boundedness of the numerical solution and strong convergence are ***,its mean square exponential stability is *** numerical examples are given to support the theoretical results.

关键词： Stochastic Volterra integro-differential equations Existence and uniqueness Stability Split-step theta method Convergence

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Mechanical,expansion and rheological properties of circulating fluidized bed fly ash based ecological cement:A critical review

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International Journal of Minerals,Metallurgy and Materials 2022年第9期29卷 1670-1682页

作者： wei zhang Xiaoming Liu Zengqi zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Circulating fluidized bed fly ash(CFBFA)is a solid waste product from circulating fluidized bed(CFB)boilers in power plants,and the storage of CFBFA is increasingly become an environmental *** scholars have made contributions to improve the resource utilization of ***,ecological cement is prepared by CFBFA,which is more conducive to its large-scale *** recent years,a lot of effort has been paid to improve the properties of ecological cement containing *** this work,the physicochemical properties of CFBFA are introduced,and recent research progress on the mechanical,expansion,and rheological properties of CFBFA based ecological cement(CEC)is extensively *** problem of over-expansion of f-CaO is summarized,which limits the scale application of CFBFA in ecological ***,the challenge for f-CaO in CFBFA to compensate for cement volume shrinkage is proposed,which is beneficial to the utilization of CFBFA in ecological cement,and the reduction of CO_(2) emissions from the cement *** addition,the environmental performance,durability,and economy of CEC should be valued in future research,especially the environmental performance,because the CFBFA contains heavy metals,such as Cr,As,which may pollute groundwater.

关键词： circulating fluidized bed fly ash ecological cement expansion durability compensation shrinkage

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A Composite Adaptive Fault-Tolerant Attitude Control for a Quadrotor UAV with Multiple Uncertainties

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Journal of Systems Science & Complexity 2022年第1期35卷 81-104页

作者： WANG Ban zhang Youmin zhang wei School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Department of Mechanical Industrial and Aerospace EngineeringConcordia UniversityMontreal H3G 1M8QCCanada

In this paper,a composite adaptive fault-tolerant control strategy is proposed for a quadrotor unmanned aerial vehicle(UAV)to simultaneously compensate actuator faults,model uncertainties and external *** assuming knowledge of the bounds on external disturbances,a baseline sliding mode control is first designed to achieve the desired system tracking performance and retain insensitive to ***,regarding actuator faults and model uncertainties of the quadrotor UAV,neural adaptive control schemes are constructed and incorporated into the baseline sliding mode control to deal with ***,in terms of unknown external disturbances,a disturbance observer is designed and synthesized with the control law to further improve the robustness of the proposed control ***,a series of comparative simulation tests are conducted to validate the effectiveness of the proposed control strategy where a quadrotor UAV is subject to inertial moment variations and different level of actuator *** capabilities and advantages of the proposed control strategy are confirmed and verified by simulation results.

关键词： Actuator fault composite adaptive fault-tolerant control external disturbance model uncertainty quadrotor UAV

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Light field super-resolution using complementary-view feature attention

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Computational Visual Media 2023年第4期9卷 843-858页

作者： wei zhang wei Ke Da Yang Hao Sheng zhang Xiong Faculty of Applied Sciences Macao Polytechnic UniversityMacao SAR 999078China State Key Laboratory of Software Development Environment School of Computer Science and EngineeringBeihang UniversityBeijing 100191Chinaand Beihang Hangzhou Innovation Institute YuhangXixi Octagon CityYuhang DistrictHangzhou 310023China

Light field(LF)cameras record multiple perspectives by a sparse sampling of real scenes,and these perspectives provide complementary *** information is beneficial to LF super-resolution(LFSR).Compared with traditional single-image super-resolution,LF can exploit parallax structure and perspective correlation among different LF ***,the performance of existing methods are limited as they fail to deeply explore the complementary information across LF *** this paper,we propose a novel network,called the light field complementary-view feature attention network(LF-CFANet),to improve LFSR by dynamically learning the complementary information in LF ***,we design a residual complementary-view spatial and channel attention module(RCSCAM)to effectively interact with complementary information between complementary ***,RCSCAM captures the relationships between different channels,and it is able to generate informative features for reconstructing LF images while ignoring redundant ***,a maximum-difference information supplementary branch(MDISB)is used to supplement information from the maximum-difference angular positions based on the geometric structure of LF *** branch also can guide the process of *** results on both synthetic and real-world datasets demonstrate the superiority of our *** proposed LF-CFANet has a more advanced reconstruction performance that displays faithful details with higher SR accuracy than state-of-the-art methods.

关键词： light field(LF) super-resolution(SR) attention

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Level density of odd-A nuclei at saddle point

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Nuclear Science and Techniques 2023年第8期34卷 164-173页

作者： wei zhang wei Gao Gui-Tao zhang Zhi-Yuan Li School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China

Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is *** total level density is calculated via the convolution of the intrinsic level density and the collective level *** intrinsic level densities are obtained in the finite-temperature covariant density functional theory,which takes into account the nuclear deformation and pairing *** saddle points on the free energy surface in the(β_(2),γ)plane,the entropy and the associated intrinsic level density are compared with those of the global *** introducing a quasiparticle to the two neighboring even–even core nuclei,whose properties are determined by the five-dimensional collective Hamiltonian model,the collective levels of the odd-A nuclei are obtained via the CQC *** total level densities of the^(234-240)U agree well with the available experimental data and Hilaire’s ***,the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately.

关键词： Level density Covariant density functional theory Core–quasiparticle coupling model Saddle point

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Research advances on ecotype and sub-ecotype differentiation of Prochlorococcus and its environmental adaptability

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Science China Earth Sciences 2020年第11期63卷 1691-1700页

作者： wei YAN Xuejin FENG wei zhang Rui zhang Nianzhi JIAO College of Marine Science and Technology China University of GeosciencesWuhan 430074China State Key Laboratory of Marine Environmental Science Fujian Key Laboratory of Marine Carbon SequestrationCollege of Ocean and Earth SciencesXiamen UniversityXiamen 361102China

Prochlorococcus,a group of marine cyanobacteria,is the most abundant and smallest oxygen-producing photosynthetic *** is mainly distributed in the euphotic zone of tropical and subtropical oceans and is a key participant in the marine biogeochemical *** has evolved continuously to adapt to the marine environment,and can be considered a recent evolutionary form of cyanobacteria,one of the most ancient life *** diverse ecotypes and subecotypes of Prochlorococcus increase its genomic diversity and environmental adaptability,allowing Prochlorococcus to become a dominant species in its *** we review the ecotype classification and distribution,ecotype and subecotype differentiation,and environmental adaptability of *** also evaluate the role and significance of ecotype and sub-ecotype differentiation of Prochlorococcus,and discuss future research directions on this basis.

关键词： Prochlorococcus Ecotype Sub-ecotype Environmental adaptation

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Pairing superfluidity in spin-orbit coupled ultracold Fermi gases

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Science China(Physics,Mechanics & Astronomy) 2015年第1期58卷 1-11页

作者： YI wei zhang wei CUI XiaoLing Key Laboratory of Quantum Information University of Science and Technology of China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Department of Physics Renmin University of China Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

We review some recent progresses on the study of ultracold Fermi gases with synthetic spin-orbit *** particular,we focus on the pairing superfluidity in these systems at zero *** studies have shown that different forms of spin-orbit coupling in various spatial dimensions can lead to a wealth of novel pairing superfluidity.A common theme of these variations is the emergence of new pairing mechanisms which are direct results of spin-orbit-coupling-modified single-particle dispersion *** different configurations can give rise to single-particle dispersion spectra with drastic differences in symmetry,spin dependence and low-energy density of states,spin-orbit coupling is potentially a powerful tool of quantum control,which,when combined with other available control schemes in ultracold atomic gases,will enable us to engineer novel states of matter.

关键词： spin-orbit coupling ultracold Fermi gas superconductivity topological superfluid

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Signal processing for RIS-assisted millimeter-wave/terahertz communications

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National Science Review 2023年第8期10卷 15-17页

作者： wei Wang wei zhang Peng Cheng Laboratory School of Electrical Engineering and Telecommunications The University of New South Wales

INTRODUCTION The applications of millimeter-wave(mmWave, wavelength 1–10 mm) and terahertz(THz, wavelength 100 μm–1 mm) communications are facing the challenges of severe free-space path loss and obstacle blockage. Aided by directional beamforming, the free-space path loss of mm Wave/THz communications with a fixed effective aperture is potentially capable of reaching the same level as the lower frequency band, rendering obstacle blockage the biggest hindrance to mmWave/THz communications.

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