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Comparative study on wheel-rail dynamic interactions of side-frame cross-bracing bogie and sub-frame radial bogie 被引量:4
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作者 Chunlei Yang Fu Li +2 位作者 Yunhua Huang Kaiyun Wang Baiqian He 《Journal of Modern Transportation》 2013年第1期1-8,共8页
Improving freight axle load is the most effective method to improve railway freight capability; based on the imported technologies of railway freight bogie, the 27 t axle load side-frame cross-bracing bogie and sub-fr... Improving freight axle load is the most effective method to improve railway freight capability; based on the imported technologies of railway freight bogie, the 27 t axle load side-frame cross-bracing bogie and sub-frame radial bogie are developed in China. In order to analyze and compare dynamic interactions of the two newly developed heavy-haul freight bogies, we establish a vehi- cle-track coupling dynamic model and use numerical calculation methods for computer simulation. The dynamic performances of the two bogies are simulated separately at various conditions. The results show that at the dipped joint and straight line running conditions, the wheel-rail dynamic interactions of both bogies are basically the same, but at the curve negotiation condition, the wear and the lateral force of the side-frame cross-bracing bogie are much higher than that of the sub-frame radial bogie, and the advantages become more obvious when the curve radius is smaller. The results also indicate that the sub- frame radial bogie has better low-wheel-rail interaction characteristics. 展开更多
关键词 Heavy haul Side-frame cross-bracing bogie .Sub-frame radial bogie . wheel-rail dynamic interaction
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An experimental study on the effects of friction modifiers on wheel-rail dynamic interactions with various angles of attack 被引量:1
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作者 Zhen Yang Pan Zhang +1 位作者 Jan Moraal Zili Li 《Railway Engineering Science》 2022年第3期360-382,共23页
By modifying friction to the desired level,the application of friction modifiers(FMs)has been considered as a promising emerging tool in the railway engineering for increasing braking/traction force in poor adhesion c... By modifying friction to the desired level,the application of friction modifiers(FMs)has been considered as a promising emerging tool in the railway engineering for increasing braking/traction force in poor adhesion conditions and mitigating wheel/rail interface deterioration,energy consumption,vibration and noise.Understanding the effectiveness of FMs in wheel–rail dynamic interactions is crucial to their proper applications in practice,which has,however,not been well explained.This study experimentally investigates the effects of two types of top-of-rail FM,i.e.FM-A and FM-B,and their application dosages on wheel–rail dynamic interactions with a range of angles of attack(AoAs)using an innovative well-controlled V-track test rig.The tested FMs have been used to provide intermediate friction for wear and noise reduction.The effectiveness of the FMs is assessed in terms of the wheel–rail adhesion characteristics and friction rolling induced axle box acceleration(ABA).This study provides the following new insights into the study of FM:the applications of the tested FMs can both reduce the wheel–rail adhesion level and change the negative friction characteristic to positive;stick–slip can be generated in the V-Track and eliminated by FM-A but intensified by FM-B,depending on the dosage of the FMs applied;the negative friction characteristic is not a must for stick–slip;the increase in ABA with AoA is insignificant until stick–slip occurs and the ABA can thus be influenced by the applications of FM. 展开更多
关键词 Friction modifier V-track test rig ADHESION Wheel–rail dynamic interaction Angle of attack Axle box acceleration
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Toughening Recycled Waste Rubbers by Dynamic Interactions for Stress Deconcentration
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作者 Hao-Jia Guo Zhou-Liang Wu +1 位作者 Shuang-Quan Liao Ming-Chao Luo 《Chinese Journal of Polymer Science》 2026年第1期234-241,I0017,共9页
Recycling of waste rubber(WR)is crucial for the sustainable development of the rubber industry.The enhancement of interfacial interactions is the main strategy for waste polymer recycling.However,there is a lack of me... Recycling of waste rubber(WR)is crucial for the sustainable development of the rubber industry.The enhancement of interfacial interactions is the main strategy for waste polymer recycling.However,there is a lack of methods for enhancing the interfacial interactions for WR recycling because WR contains abundant inert C―H bonds.Herein,we designed thioctic acid inverse vulcanization copolymers to endow recycled WR with dynamic disulfide interfacial interactions,significantly improving the mechanical properties of recycled WR.These disulfide interfacial interactions among the recycled WR tend to exchange,which dramatically increases the fractocohesive length and prevents stress concentration near the crack tips.When recycled WR is subjected to external stress,the loads are redistributed across a broad region of adjacent regions instead of being concentrated on a limited length scale,which resists crack propagation.This work effectively recycled WR,providing a strategy for solvent-free reaction-derived inverse vulcanization copolymers to improve the toughness of WR recycling. 展开更多
关键词 Waste rubbers RECYCLING Inverse vulcanization copolymers dynamic interactions Stress deconcentration
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Hierarchical Demand Response Considering Dynamic Competing Interaction Based on Multi-agent Deep Deterministic Policy Gradient
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作者 Wenhao Wang Jiehui Zheng +3 位作者 Zhaoxi Liu Jiakun Fang Zhigang Li Q.H.Wu 《CSEE Journal of Power and Energy Systems》 2026年第1期162-174,共13页
To maximize the profits of power grid operators(GOs),load aggregators(LAs)and electricity customers(ECs),this paper proposes a hierarchical demand response(HDR)framework that considers competing interaction based on m... To maximize the profits of power grid operators(GOs),load aggregators(LAs)and electricity customers(ECs),this paper proposes a hierarchical demand response(HDR)framework that considers competing interaction based on multiagent deep deterministic policy gradient(MaDDPG).The ECs are divided into conventional ECs and the electric vehicles(EVs)which are managed by ECs agent(ECA)and EV agent(EVA)to exploit the flexibility of the HDR framework.Thus,the HDR is a tri-layer model determined by five types of agents engaging in competing interaction to maximize their own profits.To address the limitations of mathematical expression and participation scale in the Stackelberg game within the HDR model,a dynamic interaction mechanism is adopted.Moreover,to tackle the HDR involving various entities,the MaDDPG develops multiple agents to simulation the dynamic competing interactions between each subject as well as solve the problem of continuous action control.Furthermore,MaDDPG adopts soft target update and priority experience replay method to ensure stable and effective training,and makes the exploration strategy comprehensive by using exploration noise.Simulation studies are conducted to verify the performance of the MaDDPG with dynamic interaction mechanism in dealing with multilayer multi-agent continuous action control,compared to the double deep Q network(DDQN),deep Q network(DQN)and dueling DQN.Additionally,comparisons among the proposed HDR with the price based DR(PBDR)and incentive based DR(IBDR)are analyzed to investigate the flexibility of the HDR. 展开更多
关键词 Continuous action control deep reinforcement learning demand response dynamic interaction mechanism MULTI-AGENT
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Vibration characteristics of ballastless track and its effect on wheel-rail broadband dynamic interaction 被引量:1
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作者 Chaozhi MA Liang GAO +3 位作者 Pu WANG Bolun AN Peng ZHOU Mahantesh M NADAKATTI 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 2025年第6期585-604,共20页
The wheel-rail dynamic load(WRL)and its vibration energy transfer(VET)are foundational for studying ballastless track dynamics in high-speed railways.In this study,the higher-order modal parameters of track beds with ... The wheel-rail dynamic load(WRL)and its vibration energy transfer(VET)are foundational for studying ballastless track dynamics in high-speed railways.In this study,the higher-order modal parameters of track beds with different isolating layers were identified experimentally and a vehicle-track coupled dynamic model considering track bed broadband vibrations(TBBVs)was established.The WRL and its VET were investigated,and the contribution law as well as the influence mechanism of TBBVs on them was determined.The results showed the WRL and track bed vibration energy exhibited significant resonances,with more prominent high-frequency resonance peaks in the track bed vibration energy.TBBVs had a significant effect on low-frequency WRLs,and markedly influenced the VET across various frequency bands.Intense low-frequency and weak high-frequency intermodulation effects between the wheel-rail and track beds were observed.The effect of track bed vibrations can be disregarded when focusing on high-frequency WRLs above 200 Hz.Variations in the isolating layer stiffness have more significant effects on the track bed vibration energy than the WRL.Rational stiffness of the isolating layer should be selected to avoid mode-coupling resonance from track beds to the wheel-rail subsystem. 展开更多
关键词 Ballastless track Higher-order modal testing wheel-rail dynamic load(WRL) Vibration energy transfer (VET) Intermodulation effect Rational stiffness
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Interactive Dynamic Graph Convolution with Temporal Attention for Traffic Flow Forecasting
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作者 Zitong Zhao Zixuan Zhang Zhenxing Niu 《Computers, Materials & Continua》 2026年第1期1049-1064,共16页
Reliable traffic flow prediction is crucial for mitigating urban congestion.This paper proposes Attentionbased spatiotemporal Interactive Dynamic Graph Convolutional Network(AIDGCN),a novel architecture integrating In... Reliable traffic flow prediction is crucial for mitigating urban congestion.This paper proposes Attentionbased spatiotemporal Interactive Dynamic Graph Convolutional Network(AIDGCN),a novel architecture integrating Interactive Dynamic Graph Convolution Network(IDGCN)with Temporal Multi-Head Trend-Aware Attention.Its core innovation lies in IDGCN,which uniquely splits sequences into symmetric intervals for interactive feature sharing via dynamic graphs,and a novel attention mechanism incorporating convolutional operations to capture essential local traffic trends—addressing a critical gap in standard attention for continuous data.For 15-and 60-min forecasting on METR-LA,AIDGCN achieves MAEs of 0.75%and 0.39%,and RMSEs of 1.32%and 0.14%,respectively.In the 60-min long-term forecasting of the PEMS-BAY dataset,the AIDGCN out-performs the MRA-BGCN method by 6.28%,4.93%,and 7.17%in terms of MAE,RMSE,and MAPE,respectively.Experimental results demonstrate the superiority of our pro-posed model over state-of-the-art methods. 展开更多
关键词 Traffic flow prediction interactive dynamic graph convolution graph convolution temporal multi-head trend-aware attention self-attention mechanism
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Quantitative principles of dynamic interaction between rock support and surrounding rock in rockburst roadways 被引量:6
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作者 Lianpeng Dai Dingjie Feng +4 位作者 Yishan Pan Aiwen Wang Ying Ma Yonghui Xiao Jianzhuo Zhang 《International Journal of Mining Science and Technology》 2025年第1期41-55,共15页
Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effe... Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering the dynamic support stress, thus deriving formulas and providing characteristic curves for describing the interaction between the support and surrounding rock. Design principles and parameters of supports for rockburst control are proposed. The results show that only when the geostress magnitude exceeds a critical value can it drive the formation of rockburst conditions. The main factors influencing the convergence response and rockburst occurrence around roadways are geostress, rock brittleness, uniaxial compressive strength, and roadway excavation size. Roadway support devices can play a role in controlling rockburst by suppressing the squeezing evolution of the surrounding rock towards instability points of rockburst. Further, the higher the strength and the longer the impact stroke of support devices with constant resistance, the more easily multiple balance points can be formed with the surrounding rock to control rockburst occurrence. Supports with long impact stroke allow adaptation to varying geostress levels around the roadway, aiding in rockburst control. The results offer a quantitative method for designing support systems for rockburst-prone roadways. The design criterion of supports is determined by the intersection between the convergence curve of the surrounding rock and the squeezing deformation curve of the support devices. 展开更多
关键词 Deep roadway ROCKBURST dynamic interaction Rock support Surrounding rock Rockburst control
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Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling Systems
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作者 Sabrina Meddah Sid Ahmed Tadjer +3 位作者 Abdelhakim Idir Kong Fah Tee Mohamed Zinelabidine Doghmane Madjid Kidouche 《Structural Durability & Health Monitoring》 EI 2025年第1期77-103,共27页
Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emp... Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry. 展开更多
关键词 Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis field data analysis
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Mechano‑electro‑optical conversion dynamics in mechanoluminescence and its application in remote human–robot interaction
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作者 Haoliang Cheng Shuangqiang Fang +7 位作者 Yi Li Qiangqiang Zhu Yixi Zhuang Rongjun Xie Wei Yan Ding Zhao Min Qiu Le Wang 《PhotoniX》 2025年第1期826-843,共18页
Mechanoluminescence(ML)is bringing a paradigm-shifting for next-generation lightbased human–robot interaction.However,the overlooked character of ML temporal dynamic response remains a critical barrier to overcoming ... Mechanoluminescence(ML)is bringing a paradigm-shifting for next-generation lightbased human–robot interaction.However,the overlooked character of ML temporal dynamic response remains a critical barrier to overcoming the limitation of mechanooptical conversion efficiency.Here,by resolving the dynamic interplay among stimuli rate,interfacial charge accumulation and ML performance of three typical materials,like ZnS:Cu^(2+),SrAl_(2)O_(4):Eu^(2+),Dy^(3+),Y_(3)Al_(5)O_(12):Ce^(3+),the cognition of ML has been deeply understand.Obviously,the ML performance is predominantly governed by the crosscoupling of stimuli rate and stimuli time rather than absolute stress magnitude.For the first time,the optimal stretching stimulation rate for commercial ZnS:Cu^(2+),SrAl_(2)O_(4):Eu^(2+),Dy^(3+)and Y_(3)Al_(5)O_(12):Ce^(3+)are respectively determined as~10.3 Mpa/s,~11.0 Mpa/s,~31.9 Mpa/s,which is of great significance for obtaining high-performance ML behavior,and an ubiquitous ML hysteresis phenomenon is demonstrated originating from a time-consuming mechano-electro-optical conversion process even existing in trap-controlled SrAl_(2)O_(4):Eu^(2+),Dy^(3+).Moreover,a qualitative relationship for ML brightness(MLB),stimuli rate(sr),stimuli time(st),inherent interfacial triboelectricity coefficient(iitre)and relative interfacial triboelectricity coefficient(ritre)is established as ML B=f(sr)*g(st)*p(iitre)*q(ritre)for guiding the design of ML elastomers.For instance,based on this equation,a topology-optimized Y_(3)Al_(5)O_(12):Ce^(3+)@polydimethylsiloxane(PDMS)elastomer is engineered,achieving unprecedented 693 times brighter emission,78%lower stress threshold and 20%lighter weight,which is successfully applied in remote control(~450 m)of quadruped robot.Three main contributions of this work include:(i)demonstrating the influence law of temporal dynamic stimulation on ML performance.(ii)resolving long-standing mechano-optical asynchrony debates.(iii)establishing a universal guideline for designing high-performance ML platforms. 展开更多
关键词 MECHANOLUMINESCENCE Mechano-electro-optical conversion Temporal dynamic response Remote human-robot interaction
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Correction:Neural Dynamics of Visual Stream Interactions During Memory-Guided Actions Investigated by Intracranial EEG
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作者 Sofiia Moraresku Jiri Hammer +6 位作者 Vasileios Dimakopoulos Michaela Kajsova Radek Janca Petr Jezdik Adam Kalina Petr Marusic Kamil Vlcek 《Neuroscience Bulletin》 2025年第9期1709-1709,共1页
Correction to:Neuroscience Bulletin https://doi.org/10.1007/s12264-025-01371-x In this article the affiliation"Department of Circuit Theory,Faculty of Electrical Engineering,Czech Technical University in Prague,M... Correction to:Neuroscience Bulletin https://doi.org/10.1007/s12264-025-01371-x In this article the affiliation"Department of Circuit Theory,Faculty of Electrical Engineering,Czech Technical University in Prague,Member of the Epilepsy Research Centre Prague-EpiReC Consortium,Prague,Czechia"should only be assigned to Radek Janca and Petr Jezdik.It is removed from the authors:Jiri Hammer,Michaela Kajsova,Adam Kalina,Petr Marusic,and Kamil Vlcek. 展开更多
关键词 visual stream interactions memory guided actions neural dynamics neuroscience intracranial EEG
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Research on Design Method of Dynamic Shop Floor Scheduling System Based on Human-computer Interaction
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作者 Songling TIAN Zhuke CAI +1 位作者 Xiaoqiang WU Xiaoqian QI 《Mechanical Engineering Science》 2025年第2期17-26,共10页
The shop floor dynamic scheduling system based on human-computer interaction is the use of computer-aided decision-making and human-computer interaction to solve the dynamic scheduling problem.A human-computer interac... The shop floor dynamic scheduling system based on human-computer interaction is the use of computer-aided decision-making and human-computer interaction to solve the dynamic scheduling problem.A human-computer interaction interface based on Gantt chart is designed,which can not only comprehensively and quantitatively represent the scheduling process and scheduling scheme,but also have friendly human-computer interaction performance.The data transmission and interaction architecture is constructed to realize the rapid response to shop floor disturbance events.A priority calculation algorithm integrating priority rules and dispatcher preference is proposed,which realizes the automatic calculation of priority for the dispatcher's reference and reduces theirburden.A man-machine interactive shop floor dynamic scheduling strategy is proposed.When solving the dynamic flexible job shop scheduling problem caused by machine tool breakdown and urgent order,the origin moments obtained by using this strategy are 0.4190 and 0.3703 respectively.As can be seen from the origin moment indicator,the dynamic shop floor scheduling system based on the human-computer interaction is efficient and reliable in solving dynamic scheduling problems,and related strategies of this system are also feasible and stable. 展开更多
关键词 Human-computer interaction dynamic scheduling Flexible shop floor scheduling Perturbation events
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Rheological behaviors of Na-montmorillonite considering particle interactions:A molecular dynamics study
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作者 Siqi Zhang Daoyuan Tan +2 位作者 Honghu Zhu Huafu Pei Bin Shi 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第7期4657-4671,共15页
Understanding the rheology of bentonite suspensions is crucial for ensuring the safety of engineering practices.However,the rheological mechanisms of bentonite remain unclear due to the limitations of conventional exp... Understanding the rheology of bentonite suspensions is crucial for ensuring the safety of engineering practices.However,the rheological mechanisms of bentonite remain unclear due to the limitations of conventional experimental techniques,particularly in assessing the microscopic interactions between clay particles and their impact on rheological properties.In this paper,the rheological behaviors of Namontmorillonite were studied with a focus on interparticle interactions.Both equilibrium molecular dynamics(MD)and non-equilibrium MD simulations were conducted to understand the physical properties of Na-montmorillonite under zero shear and various shear rates,respectively.The interaction between two parallel clay particles was determined in simulations,indicating that the classical Darjaguin-Landau-Verwey-Overbeek(DLVO)theory underestimates the interactions for a small separation distance.Na-montmorillonite exhibits a typical shear thinning behavior under shearing.However,as water content increases,it begins to behave more like liquid water.The yield stress of montmorillonite,as determined by the Bingham model,was found to be linearly related to the interaction pressures between clay particles.Besides MD simulations,the microstructure of clay suspension was further quantified using the separation distance and incline angle between non-parallel clay particles.Based on MD results and the quantified clay structure,a model was developed to estimate the yield stress of montmorillonite considering various influence factors,including electrolyte concentration,temperature,and solid fraction.Finally,from a comparison with calculated and experimental data,the results confirm the good performance of the proposed model.These findings provide significant insights for understanding the rheological soil behaviors and evaluating the yield stress of bentonite suspensions. 展开更多
关键词 Rheological behavior Yield stress Molecular dynamics Particle interactions Darjaguin-Landau-Verwey-Overbeek(DLVO)theory Microstructure Montmorillonite suspension
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Modulation of d-d orbital interactions in Ti-Ni-N_(4)coordination introduces dynamic bonding for enhanced CO_(2)photoreduction
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作者 Song-Song Zhi Xiao-Xiao Zou +6 位作者 Jin-Ye Lei Lu Zhang Zi-Han Li Wan-Nuo Gu Fahim Ullah Hong Guo Da-Peng Wu 《Rare Metals》 2025年第10期7464-7475,共12页
Photocatalytic CO_(2)reduction using atomically dispersed catalysts holds significant potential for addressing global energy and environmental challenges.However,the influence of d-d orbital interactions between metal... Photocatalytic CO_(2)reduction using atomically dispersed catalysts holds significant potential for addressing global energy and environmental challenges.However,the influence of d-d orbital interactions between metal centers and coordinated atoms remains under explored.Herein,nickel phthalocyanine is anchored to the metalexposed crystal face of TiO_(2),forming Ti-Ni-N_(4)coordination.This configuration reveals that the axially coordinated Ti atoms serve as a novel electron channel with electron-donating ability,transferring electrons to the Ni center through d-d coupling.It is found that the dynamic adjustment of bond lengths and d-band centers in Ti-Ni bonding during CO_(2)photoreduction process can effectively modulate the adsorption strengths of the Ni center for different intermediates.This leads to a significant enhancement in the photocatalytic performance for CO_(2)reduction to CO without a sacrificial reagent,achieving an exceptional CO evolution rate of 378.5μmol g^(-1).Furthermore,the d-d coupling mediated by Ti-Ni-N_(4)coordination increases the vacancy formation energy of active sites,preventing the leaching of Ni active centers.This study provides a strategy for the precise design of d-d orbital regulation and resistance to demetallization in photocatalysts for efficient CO_(2)conversion. 展开更多
关键词 d-d orbital interaction dynamic bonding Ni demetallization Photocatalytic CO_(2)reduction
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Soliton Interactions and Collision Dynamics in a Variable-Coefficient Coupled Nonlocal Nonlinear Schrödinger Systems
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作者 Xinnan Cui Zhiyang Zhang +2 位作者 Muwei Liu Fenghua Qi Wenjun Liu 《Chinese Physics Letters》 2025年第10期68-74,共7页
The coupled nonlocal nonlinear Schrödinger equations with variable coefficients are researched using the nonstandard Hirota bilinear method.The two-soliton and double-hump one-soliton solutions for the equations ... The coupled nonlocal nonlinear Schrödinger equations with variable coefficients are researched using the nonstandard Hirota bilinear method.The two-soliton and double-hump one-soliton solutions for the equations are first obtained.By assigning different functions to the variable coefficients,we obtain V-shaped,Y-shaped,wave-type,exponential solitons,and so on.Next,we reveal the influence of the real and imaginary parts of the wave numbers on the double-hump structure based on the soliton solutions.Finally,by setting different wave numbers,we can change the distance and transmission direction of the solitons to analyze their dynamic behavior during collisions.This study establishes a theoretical framework for controlling the dynamics of optical fiber in nonlocal nonlinear systems. 展开更多
关键词 two soliton solutions soliton interactions assigning different functions collision dynamics nonstandard hirota bilinear methodthe nonstandard hirota bilinear method variable coefficient coupled nonlocal nonlinear schr dinger systems coupled nonlocal nonlinear schr dinger equations variable coefficients
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Short-chain Length Dependence of Equilibrium Dynamics and Nonlinear Rheology in Unentangled Long-chain/Short-chain Polymer Blends
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作者 Xiao-Yang Wang Bo Liu +2 位作者 Li-Jia An Zhen-Hua Wang Yu-Yuan Lu 《Chinese Journal of Polymer Science》 2026年第2期525-535,I0016,共12页
The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behav... The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends. 展开更多
关键词 Unentangled polymer blend Nonlinear rheology Equilibrium dynamics Hydrodynamic interaction screening Molecular dynamics simulation
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Light-induced modulation of electrical,optical,and thermodynamic properties via nonlinear phononics in perovskite KTaO_(3)
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作者 Qi Yang Hong Zhang 《Chinese Physics B》 2026年第2期499-509,共11页
Strong long-wavelength laser pulses enable direct manipulation of atomic lattices for engineering novel quantum states in complex materials.Nonlinear coupling between two infrared-active phonon modes(TO_(1) and TO_(2)... Strong long-wavelength laser pulses enable direct manipulation of atomic lattices for engineering novel quantum states in complex materials.Nonlinear coupling between two infrared-active phonon modes(TO_(1) and TO_(2)),induced by intense terahertz light fields,significantly enhances the amplitude of the TO_(1) mode and facilitates ultrafast control of transient structural distortions.This light-induced distortion reduces the lattice thermal conductivity from 8.1 W·m^(-1)·K^(-1)to 3.0 W·m^(-1)·K^(-1).The reduction originates from the nonlinear coupling,which enhances anharmonic interactions in the lattice potential energy and substantially shortens the phonon lifetime(τ).This work demonstrates a strategy applicable to other perovskite materials and provides a framework for investigating light-induced electrical,optical,and thermodynamic phase transitions. 展开更多
关键词 ultrafast processes ultrafast dynamics first-principles calculation phonon–phonon interactions
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Seismic wave input method for three-dimensional soil-structure dynamic interaction analysis based on the substructure of artificial boundaries 被引量:21
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作者 Liu Jingbo Tan Hui +2 位作者 Bao Xin Wang Dongyang Li Shutao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第4期747-758,共12页
The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident... The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves. 展开更多
关键词 soil-structure dynamic interaction SEISMIC WAVE INPUT WAVE method EQUIVALENT INPUT SEISMIC loads SUBSTRUCTURE of artifi cial boundaries
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Application of Computational Fluid Dynamics and Fluid Structure Interaction Techniques for Calculating the 3D Transient Flow of Journal Bearings Coupled with Rotor Systems 被引量:21
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作者 LI Qiang YU Guichang +1 位作者 LIU Shulian ZHENG Shuiying 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第5期926-932,共7页
Journal bearings are important parts to keep the high dynamic performance of rotor machinery. Some methods have already been proposed to analysis the flow field of journal bearings, and in most of these methods simpli... Journal bearings are important parts to keep the high dynamic performance of rotor machinery. Some methods have already been proposed to analysis the flow field of journal bearings, and in most of these methods simplified physical model and classic Reynolds equation are always applied. While the application of the general computational fluid dynamics (CFD)-fluid structure interaction (FSI) techniques is more beneficial for analysis of the fluid field in a journal bearing when more detailed solutions are needed. This paper deals with the quasi-coupling calculation of transient fluid dynamics of oil film in journal bearings and rotor dynamics with CFD-FSI techniques. The fluid dynamics of oil film is calculated by applying the so-called "dynamic mesh" technique. A new mesh movement approacb is presented while the dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings. The proposed mesh movement approach is based on the structured mesh. When the joumal moves, the movement distance of every grid in the flow field of bearing can be calculated, and then the update of the volume mesh can be handled automatically by user defined function (UDF). The journal displacement at each time step is obtained by solving the moving equations of the rotor-bearing system under the known oil film force condition. A case study is carried out to calculate the locus of the journal center and pressure distribution of the journal in order to prove the feasibility of this method. The calculating results indicate that the proposed method can predict the transient flow field of a journal bearing in a rotor-bearing system where more realistic models are involved. The presented calculation method provides a basis for studying the nonlinear dynamic behavior of a general rotor-bearing system. 展开更多
关键词 mesh movement transient flow computational fluid dynamics (CFD) fluid-structure interaction (FSI) journal bearing
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Elastic responses of underground circular arches considering dynamic soil-structure interaction:A theoretical analysis 被引量:12
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作者 Hai-Long Chen Feng-Nian Jin Hua-Lin Fan 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第1期110-122,共13页
Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibra... Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equa- tion of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal super- position. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches. 展开更多
关键词 Underground protective arches - dynamic soilstructure interaction dynamic responses Analytical solution
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Human Interaction Dynamics for Its Use in Mobile Robotics:Impedance Control for Leader-follower Formation 被引量:12
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作者 Daniel Herrera Flavio Roberti +1 位作者 Marcos Toibero Ricardo Carelli 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第4期696-703,共8页
A complete characterization of the behavior in human-robot interactions(HRI) includes both: the behavioral dynamics and the control laws that characterize how the behavior is regulated with the perception data. In thi... A complete characterization of the behavior in human-robot interactions(HRI) includes both: the behavioral dynamics and the control laws that characterize how the behavior is regulated with the perception data. In this way, this work proposes a leader-follower coordinate control based on an impedance control that allows to establish a dynamic relation between social forces and motion error. For this, a scheme is presented to identify the impedance based on fictitious social forces, which are described by distance-based potential fields.As part of the validation procedure, we present an experimental comparison to select the better of two different fictitious force structures. The criteria are determined by two qualities: least impedance errors during the validation procedure and least parameter variance during the recursive estimation procedure.Finally, with the best fictitious force and its identified impedance,an impedance control is designed for a mobile robot Pioneer 3AT,which is programmed to follow a human in a structured scenario.According to results, and under the hypothesis that moving like humans will be acceptable by humans, it is believed that the proposed control improves the social acceptance of the robot for this kind of interaction. 展开更多
关键词 Human modeling human-machine interaction impedance control robot dynamics social robotics
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