With the in-depth implementation of sustainable development strategies,hydrogen energy as a clean energy source is receiving increasing attention[1,2].Among the various methods of hydrogen production,the electrocataly...With the in-depth implementation of sustainable development strategies,hydrogen energy as a clean energy source is receiving increasing attention[1,2].Among the various methods of hydrogen production,the electrocatalytic decomposition of abundant seawater into hydrogen utilizing renewable energy has emerged as a green and promising approach.However,natural seawater contains complex components,such as halide ions,which lead to the corrosion of catalysts or the occurrence of competitive side reactions during the electrolysis process[3].展开更多
Spin-density(charge)separation,marked by distinct propagation velocities of spin and density excitations,epitomizes strong correlations,historically confined to one-dimensional(1D)systems.The recent experimental work ...Spin-density(charge)separation,marked by distinct propagation velocities of spin and density excitations,epitomizes strong correlations,historically confined to one-dimensional(1D)systems.The recent experimental work of Dhar et al(2025 Nature 64253),using a weakly interacting 3D Bose-Einstein condensate of^(133)Cs atoms confined in a 2D optical lattice to realize spin-density separation and demonstrate boson anyonization,motivates a deeper exploration into how dimensionality and interactions govern quantum correlations.In this work,we investigate this in two-component bosonic mixtures with finite-range interactions,probing 1D and 3D dynamics.Using path integral effective field theory within the one-loop approximation,we derive analytical expressions for zero-temperature ground-state energy and quantum depletion,seamlessly recovering contact interaction results in the contact limit.By crafting an effective action for decoupled density and spin modes,we compute dynamic structure factors(DSFs),revealing how finite-range interactions sculpt spin-density separation.A pivotal finding is the dimensionality-driven divergence in DSF peak dynamics:in 1D,peaks ascend to higher frequencies with increasing interaction strength,yielding sharp responses;in 3D,peaks descend to lower frequencies,with broader density wave profiles.These insights highlight dimensionality's critical role in collective excitations and provide a robust theoretical blueprint for probing interaction-driven quantum phenomena via Bragg spectroscopy,paving new pathways for the exploration of dimensionally tuned quantum correlations in ultracold quantum gases.展开更多
The performance of polymer electrolytes in lithium metal batteries(LMBs)is often hindered by strong Li^(+)-ligand coordination,which leads to tightly bound solvation shells and restricts ion transport by coupling it t...The performance of polymer electrolytes in lithium metal batteries(LMBs)is often hindered by strong Li^(+)-ligand coordination,which leads to tightly bound solvation shells and restricts ion transport by coupling it to polymer segmental motion.In this study,a low-content ionic plasticizer additive1-butyl-3-dimethylimidazolium bromide(BMImBr)was introduced into the PVDF-HFP/LiTFSI/DMF matrix to modulate the Li^(+)solvation environment.Unlike conventional dual-salt systems,the introduced Br-anions dynamically compete for Li^(+)coordination,disrupting the rigid Li^(+)-TFSI^(-)/DMF solvation shell and constructing a"statistically labile and diffuse ionic cloud"characterized by reduced coordination numbers,weakened binding energies,and a more diffuse electrostatic potential landscape.This restructured solvation environment facilitates partially decoupled Li^(+)transport,as evidenced by dielectric spectroscopy and molecular dynamics simulations.Furthermore,the in situ formation of a LiBr-rich solid electrolyte interphase(SEI)effectively stabilizes the Li-metal interface and significantly reduces interfacial resistance.As a result,the optimized polymer electrolyte delivers outstanding electrochemical performance,achieving a high ionic conductivity of 0.8×10^(-4) S/cm,ultra-stable symmetric cell cycling over 500 h,and superior capacity retention exceeding 94%after 150 cycles at 0.5 C.This study elucidates a dynamic ion transport mechanism driven by competitive anion coordination and provides a viable strategy for simultaneously addressing the conductivity-stability trade-off in solid-state lithium metal batteries.展开更多
One of eight gates of the Pearl River Estuary,the Yamen Inlet is a bedrock channel mouth connecting the Huangmao Sea and Yamen Channel.The wider water surfaces of the upper and lower reaches of the entrance produce a ...One of eight gates of the Pearl River Estuary,the Yamen Inlet is a bedrock channel mouth connecting the Huangmao Sea and Yamen Channel.The wider water surfaces of the upper and lower reaches of the entrance produce a unique bidirectional asymmetrical jet system.Using observed hydrology and historical charts,the ECOMSED model was applied in morphodynamic analysis of the dynamic structures and dynamic equilibrium of the Yamen jet system and its effect on sedimentation.It was found that (1) the nonlinear interaction of Yamen dynamic structures could not be ignored,as while the Coriolis force and friction force were generally of the same order of magnitude,the effect of friction force was greater;(2) the bidirectional asymmetrical jet system was flood preferential flow to the north of the channel mouth and ebb preferential flow to the south;and (3) the bidirectional asymmetrical jet system was the dominant factor in the long term stability of the Yamen deep trough.展开更多
The paper deals with the dynamic response prediction of the composite structure,which consists of two linear components coupled by some nonlinear vibration isolators. Based on the measured impulse response functions o...The paper deals with the dynamic response prediction of the composite structure,which consists of two linear components coupled by some nonlinear vibration isolators. Based on the measured impulse response functions of the linear components, three kinds of dynamic equations of interfacial integration are proposed and a procedure to transform the dynamic equations of integral type into a set of ordinary differential equations is suggested. Computer simulations and a real test are given to verify the effectiveness of the theoretical results.展开更多
In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underg...In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underground structures is derived, and the generalized variational principle of nonconservative system is given, thus the fundamental of dynamical analysis for underground structures to resist blast is proposed. Finally, for the underground cylindrical structure to resist blast, dynamical calculations are made, and compared with the test results.展开更多
For general volatility structures for forward rates, the evolution of interest rates may not be Markovian and the entire path may be necessary to capture the dynamics of the term structure. This article identifies con...For general volatility structures for forward rates, the evolution of interest rates may not be Markovian and the entire path may be necessary to capture the dynamics of the term structure. This article identifies conditions on the volatility structure of forward rates that permit the dynamics of the term structure to be represented by a finite-dimensional state variable Markov process. In the deterministic volatility case, we interpret then-factor model as a sum ofn unidimensional models.展开更多
The dynamic interaction problems of three-dimensional lineqr elastic structures with arbitrary shaped section embedded in a homogeneous, isotropic and linear elastic half space under dynamic disturbances are numerical...The dynamic interaction problems of three-dimensional lineqr elastic structures with arbitrary shaped section embedded in a homogeneous, isotropic and linear elastic half space under dynamic disturbances are numerically solved. The numerical method employed is a combination of the time domain semi-analytical boundary element method (SBEM) used for the semi-infinite soil medium and the semi-analytical finite element method (SFEM) used for the three-dimensional structure. The two methods are combined through equilibrium and compatibility conditions at the soil-structure interface. Displacements, velocities, accelerations and interaction forces at the interface between underground structure and soil medium produced by the diffraction of wave by an underground structure for every time step are obtained. In dynamic soil-structure interaction problems, it is advantageous to combine the SBEM and the SFEM in an effort to produce an optimum numerical hybrid scheme which is characterized by the main advantages of the two methods. The effects of the thickness, the ratio of length and diameter of underground structure and the soil medium on dynamic responses are discussed.展开更多
Analysis method for the dynamic behavior of viscoelastically damped structures is studied.A finite element model of sandwich beams with eight degrees of freedom is set up and the finite element formulation of the equa...Analysis method for the dynamic behavior of viscoelastically damped structures is studied.A finite element model of sandwich beams with eight degrees of freedom is set up and the finite element formulation of the equations of motion is given for the viscoelastically damped structures.An iteration method for solving nonlinear eigenvalue problems is suggested to analyze the dynamic behavior of viscoelastically damped structures. The method has been applied to the complex model analysis of a sandwich cantilever beam with viscoelastic damping material core.展开更多
Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,prov...Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and microfluidics.However, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.展开更多
In this study, shaking table tests were performed to investigate the dynamic characteristics of a mold transformer. Based on the test results, rotary friction dampers were developed to mitigate the excessive lateral d...In this study, shaking table tests were performed to investigate the dynamic characteristics of a mold transformer. Based on the test results, rotary friction dampers were developed to mitigate the excessive lateral displacement that occurred along the direction of the weak stiffness axis of the mold transformer. In addition, shaking table tests were performed by attaching friction dampers to both sides of the mold transformer. Based on the shaking table test results, the natural frequency, mode vector, and damping ratio of the mold transformer were derived using the transfer function and half-power bandwidth. The test results indicated that the use of friction dampers can decrease the displacement and acceleration response of the mold transformer. Finally, dynamic structural models were established considering the component connectivity and mass distribution of the mold transformer. In addition, a numerical strategy was proposed to calibrate the stiffness coefficients of the mold transformer, thereby facilitating the relationship between generalized mass and stiffness. The results indicated that the analytical model based on the calibration strategy of stiffness coefficients can reasonably simulate the dynamic behavior of the mold transformer using friction dampers with regard to transfer function, displacement, and acceleration response.展开更多
Luminescent nanoclusters(NCs)have attracted much attention because of their superior photophysical properties;however,the design of dynamic NCs with reversible structural change is highly challenging.Herein,we synthes...Luminescent nanoclusters(NCs)have attracted much attention because of their superior photophysical properties;however,the design of dynamic NCs with reversible structural change is highly challenging.Herein,we synthesize a kind of dynamic luminescent NCs through Schiff base crosslinking between triethylenetetramine(TETA)and tannic acid at room temperature.The proposed NCs have an excitation-independent blue emission,and the maximum emission is available at about 458 nm with two excitation centers.Furthermore,the crosslinking degree of the NCs can be effectively adjusted by TETA and their formation is a kineticcontrol process.Most importantly,the proposed NCs show a property of pHcontrolled reversible depolymerization and polymerization,accompanied by a cyclic“on-off-on”photoswitching,which is directly attributed to pH-stimulated reversible C=N bond cleavage and re-formation.Because of the reversible structure change properties,the dynamic NCs have been well used in reversible information encryption.This new finding provides not only us with a powerful strategy to study the structure–properties relationship of luminescent NCs but also a design idea for constructing smart optical nanomaterials.展开更多
In recent years,the evolution of the community structure in social networks has gained significant attention.Due to the rapid and continuous evolution of real-world networks over time.This makes the process of identif...In recent years,the evolution of the community structure in social networks has gained significant attention.Due to the rapid and continuous evolution of real-world networks over time.This makes the process of identifying communities and tracking their topology changes challenging.To tackle these challenges,it is necessary to find efficient methodologies for analyzing the behavior patterns of dynamic communities.Several previous reviews have introduced algorithms and models for community detection.However,these methods have not been very accurate in identifying communities.Moreover,none of the reviewed papers made an apparent effort to link algorithms that can accurately detect dynamic communities.This review aims to present a taxonomy that shows several algorithms and methodologies for detecting dynamic communities.These algorithms are divided into four categories(heuristicand modularity-based,metaheuristic,deep learning,and hybrid deep learning).It encompasses the past five years and examines the advantages and disadvantages of conventional and recent methods.Currently,many efforts are utilizing deep learning to improve dynamic networks;however,the instability of the network during the training phase affects the model’s accuracy.However,this direction remains unexplored.This study presents a review that aims to tackle this issue.We discuss a research path that explores the integration of deep learning with heuristic,metaheuristic,and hybrid metaheuristic algorithms to facilitate the identification of communities in dynamic networks.This investigation examines how this mixture surpasses the constraints of singular methodologies,resulting in enhanced detection outcomes and enabling researchers to select the most suitable algorithms for their future research.展开更多
This paper presents a framework for constructing surrogate models for sensitivity analysis of structural dynamics behavior.Physical models involving deformation,such as collisions,vibrations,and penetration,are devel-...This paper presents a framework for constructing surrogate models for sensitivity analysis of structural dynamics behavior.Physical models involving deformation,such as collisions,vibrations,and penetration,are devel-oped using the material point method.To reduce the computational cost of Monte Carlo simulations,response surface models are created as surrogate models for the material point system to approximate its dynamic behavior.An adaptive randomized greedy algorithm is employed to construct a sparse polynomial chaos expansion model with a fixed order,effectively balancing the accuracy and computational efficiency of the surrogate model.Based on the sparse polynomial chaos expansion,sensitivity analysis is conducted using the global finite difference and Sobol methods.Several examples of structural dynamics are provided to demonstrate the effectiveness of the proposed method in addressing structural dynamics problems.展开更多
Dynamic adaptability is a key feature in biological macromolecules,enabling selective binding and catalysis[1].From DNA supercoiling to enzyme conformational changes,biological systems have evolved intricate ways to d...Dynamic adaptability is a key feature in biological macromolecules,enabling selective binding and catalysis[1].From DNA supercoiling to enzyme conformational changes,biological systems have evolved intricate ways to dynamically adjust their structures to accommodate functional needs.Mimicking this adaptability in synthetic systems is an ongoing challenge in supramolecular chemistry.展开更多
Cryo-electron microscopy makes use of transmission electron microscopy to image vitrified biological samples and reconstruct their three-dimensional structures from two-dimensional projections via computational approa...Cryo-electron microscopy makes use of transmission electron microscopy to image vitrified biological samples and reconstruct their three-dimensional structures from two-dimensional projections via computational approaches. After over40 years of development, this technique is now reaching its zenith and reforming the research paradigm of modern structural biology. It has been gradually taking over X-ray crystallography as the mainstream method. In this review, we briefly introduce the history of cryo-EM, recent technical development and its potential power to reveal dynamic structures. The technical barriers and possible approaches to tackle the upcoming challenges are discussed.展开更多
In the research of parachute, canopy inflation process modeling is one of the most complicated tasks. As canopy often experiences the largest deformations and loa-dings during a very short time, it is of great difficu...In the research of parachute, canopy inflation process modeling is one of the most complicated tasks. As canopy often experiences the largest deformations and loa-dings during a very short time, it is of great difficulty for theoretical analysis and experimental measurements. In this paper, aerodynamic equations and structural dynamics equations were developed for describing parachute opening process, and an iterative coupling solving strategy incorpo- rating the above equations was proposed for a small-scale, flexible and flat-circular parachute. Then, analyses were carried out for canopy geometry, time-dependent pressure difference between the inside and outside of the canopy, transient vortex around the canopy and the flow field in the radial plane as a sequence in opening process. The mechanism of the canopy shape development was explained from perspective of transient flow fields during the inflation process. Experiments of the parachute opening process were conducted in a wind tunnel, in which instantaneous shape of the canopy was measured by high velocity camera and the opening loading was measured by dynamometer balance. The theoretical predictions were found in good agreement with the experimental results, validating the proposed approach. This numerical method can improve the situation of strong dependence of parachute research on wind tunnel tests, and is of significance to the understanding of the mechanics of parachute inflation process.展开更多
For accurate Finite Element(FE)modeling for the structural dynamics of aeroengine casings,Parametric Modeling-based Model Updating Strategy(PM-MUS)is proposed based on efficient FE parametric modeling and model updati...For accurate Finite Element(FE)modeling for the structural dynamics of aeroengine casings,Parametric Modeling-based Model Updating Strategy(PM-MUS)is proposed based on efficient FE parametric modeling and model updating techniques regarding uncorrelated/correlated mode shapes.Casings structure is parametrically modeled by simplifying initial structural FE model and equivalently simulating mechanical characteristics.Uncorrelated modes between FE model and experiment are reasonably handled by adopting an objective function to recognize correct correlated modes pairs.The parametrized FE model is updated to effectively describe structural dynamic characteristics in respect of testing data.The model updating technology is firstly validated by the detailed FE model updating of one fixed–fixed beam structure in light of correlated/uncorrelated mode shapes and measured mode data.The PM-MUS is applied to the FE parametrized model updating of an aeroengine stator system(casings)which is constructed by the proposed parametric modeling approach.As revealed in this study,(A)the updated models by the proposed updating strategy and dynamic test data is accurate,and(B)the uncorrelated modes like close modes can be effectively handled and precisely identify the FE model mode associated the corresponding experimental mode,and(C)parametric modeling can enhance the dynamic modeling updating of complex structure in the accuracy of mode matching.The efforts of this study provide an efficient dynamic model updating strategy(PM-MUS)for aeroengine casings by parametric modeling and experimental test data regarding uncorrelated modes.展开更多
Spot weld models are widely used in finite element analysis(FEA)of automotive body in white(BIW)to predict static,dynamic,durability and other characteristics of automotive BIW.However,few researches are done on evalu...Spot weld models are widely used in finite element analysis(FEA)of automotive body in white(BIW)to predict static,dynamic,durability and other characteristics of automotive BIW.However,few researches are done on evaluation of the validity of these spot weld models in structural dynamic analysis of BIW.To evaluate the validity and accuracy of spot weld models in structural dynamic analysis of BIW,two object functions,error function and deviation function,are introduced innovatively.Modal analysis of Two-panel and Double-hat structures,which are the dominated structures in BIW,is conducted,and the values of these two object functions are obtained.Based on the values of object functions,the validity of these spot weld models are evaluated.It is found that the area contact method(ACM2)and weld element connection(CWELD)can give more precise prediction in modal analysis of these two classical structures,thus are more applicable to structural dynamic analysis of automotive BIW.Modal analysis of a classical BIW is performed,which further confirms this evaluation.The error function and deviation function proposed in this research can give guidance on the adaptability of spot weld models in structural dynamic analysis of BIW.And this evaluation method can also be adopted in evaluation of other finite element models in static,dynamic and other kinds of analysis for automotive structures.展开更多
基金financially supported by the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(No.NY223016)Qinglan Project of Jiangsu Province of China2024 Nanjing Science and Technology Innovation Program(No.NJKCZYZZ2024-06)。
文摘With the in-depth implementation of sustainable development strategies,hydrogen energy as a clean energy source is receiving increasing attention[1,2].Among the various methods of hydrogen production,the electrocatalytic decomposition of abundant seawater into hydrogen utilizing renewable energy has emerged as a green and promising approach.However,natural seawater contains complex components,such as halide ions,which lead to the corrosion of catalysts or the occurrence of competitive side reactions during the electrolysis process[3].
基金supported by the National Natural Science Foundation of China(Grant No.12574301)the Zhejiang Provincial Natural Science Foundation(Grant No.LZ25A040004)。
文摘Spin-density(charge)separation,marked by distinct propagation velocities of spin and density excitations,epitomizes strong correlations,historically confined to one-dimensional(1D)systems.The recent experimental work of Dhar et al(2025 Nature 64253),using a weakly interacting 3D Bose-Einstein condensate of^(133)Cs atoms confined in a 2D optical lattice to realize spin-density separation and demonstrate boson anyonization,motivates a deeper exploration into how dimensionality and interactions govern quantum correlations.In this work,we investigate this in two-component bosonic mixtures with finite-range interactions,probing 1D and 3D dynamics.Using path integral effective field theory within the one-loop approximation,we derive analytical expressions for zero-temperature ground-state energy and quantum depletion,seamlessly recovering contact interaction results in the contact limit.By crafting an effective action for decoupled density and spin modes,we compute dynamic structure factors(DSFs),revealing how finite-range interactions sculpt spin-density separation.A pivotal finding is the dimensionality-driven divergence in DSF peak dynamics:in 1D,peaks ascend to higher frequencies with increasing interaction strength,yielding sharp responses;in 3D,peaks descend to lower frequencies,with broader density wave profiles.These insights highlight dimensionality's critical role in collective excitations and provide a robust theoretical blueprint for probing interaction-driven quantum phenomena via Bragg spectroscopy,paving new pathways for the exploration of dimensionally tuned quantum correlations in ultracold quantum gases.
基金the China Scholarship Council(CSC)for a doctoral scholarship(Grant Nos.202006310030,202108530138 and 202108530139)。
文摘The performance of polymer electrolytes in lithium metal batteries(LMBs)is often hindered by strong Li^(+)-ligand coordination,which leads to tightly bound solvation shells and restricts ion transport by coupling it to polymer segmental motion.In this study,a low-content ionic plasticizer additive1-butyl-3-dimethylimidazolium bromide(BMImBr)was introduced into the PVDF-HFP/LiTFSI/DMF matrix to modulate the Li^(+)solvation environment.Unlike conventional dual-salt systems,the introduced Br-anions dynamically compete for Li^(+)coordination,disrupting the rigid Li^(+)-TFSI^(-)/DMF solvation shell and constructing a"statistically labile and diffuse ionic cloud"characterized by reduced coordination numbers,weakened binding energies,and a more diffuse electrostatic potential landscape.This restructured solvation environment facilitates partially decoupled Li^(+)transport,as evidenced by dielectric spectroscopy and molecular dynamics simulations.Furthermore,the in situ formation of a LiBr-rich solid electrolyte interphase(SEI)effectively stabilizes the Li-metal interface and significantly reduces interfacial resistance.As a result,the optimized polymer electrolyte delivers outstanding electrochemical performance,achieving a high ionic conductivity of 0.8×10^(-4) S/cm,ultra-stable symmetric cell cycling over 500 h,and superior capacity retention exceeding 94%after 150 cycles at 0.5 C.This study elucidates a dynamic ion transport mechanism driven by competitive anion coordination and provides a viable strategy for simultaneously addressing the conductivity-stability trade-off in solid-state lithium metal batteries.
基金supported by Guangdong Natural Science Foundation (Grant No. 9151027501000111)‘908’ Marine Survey Project (Grant No. 908-02-01-04)National Natural Science Foundation of China (Grant No. 50839005)
文摘One of eight gates of the Pearl River Estuary,the Yamen Inlet is a bedrock channel mouth connecting the Huangmao Sea and Yamen Channel.The wider water surfaces of the upper and lower reaches of the entrance produce a unique bidirectional asymmetrical jet system.Using observed hydrology and historical charts,the ECOMSED model was applied in morphodynamic analysis of the dynamic structures and dynamic equilibrium of the Yamen jet system and its effect on sedimentation.It was found that (1) the nonlinear interaction of Yamen dynamic structures could not be ignored,as while the Coriolis force and friction force were generally of the same order of magnitude,the effect of friction force was greater;(2) the bidirectional asymmetrical jet system was flood preferential flow to the north of the channel mouth and ebb preferential flow to the south;and (3) the bidirectional asymmetrical jet system was the dominant factor in the long term stability of the Yamen deep trough.
文摘The paper deals with the dynamic response prediction of the composite structure,which consists of two linear components coupled by some nonlinear vibration isolators. Based on the measured impulse response functions of the linear components, three kinds of dynamic equations of interfacial integration are proposed and a procedure to transform the dynamic equations of integral type into a set of ordinary differential equations is suggested. Computer simulations and a real test are given to verify the effectiveness of the theoretical results.
文摘In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underground structures is derived, and the generalized variational principle of nonconservative system is given, thus the fundamental of dynamical analysis for underground structures to resist blast is proposed. Finally, for the underground cylindrical structure to resist blast, dynamical calculations are made, and compared with the test results.
文摘For general volatility structures for forward rates, the evolution of interest rates may not be Markovian and the entire path may be necessary to capture the dynamics of the term structure. This article identifies conditions on the volatility structure of forward rates that permit the dynamics of the term structure to be represented by a finite-dimensional state variable Markov process. In the deterministic volatility case, we interpret then-factor model as a sum ofn unidimensional models.
文摘The dynamic interaction problems of three-dimensional lineqr elastic structures with arbitrary shaped section embedded in a homogeneous, isotropic and linear elastic half space under dynamic disturbances are numerically solved. The numerical method employed is a combination of the time domain semi-analytical boundary element method (SBEM) used for the semi-infinite soil medium and the semi-analytical finite element method (SFEM) used for the three-dimensional structure. The two methods are combined through equilibrium and compatibility conditions at the soil-structure interface. Displacements, velocities, accelerations and interaction forces at the interface between underground structure and soil medium produced by the diffraction of wave by an underground structure for every time step are obtained. In dynamic soil-structure interaction problems, it is advantageous to combine the SBEM and the SFEM in an effort to produce an optimum numerical hybrid scheme which is characterized by the main advantages of the two methods. The effects of the thickness, the ratio of length and diameter of underground structure and the soil medium on dynamic responses are discussed.
文摘Analysis method for the dynamic behavior of viscoelastically damped structures is studied.A finite element model of sandwich beams with eight degrees of freedom is set up and the finite element formulation of the equations of motion is given for the viscoelastically damped structures.An iteration method for solving nonlinear eigenvalue problems is suggested to analyze the dynamic behavior of viscoelastically damped structures. The method has been applied to the complex model analysis of a sandwich cantilever beam with viscoelastic damping material core.
基金supported by the National Natural Science Foundation of China(Grant No.61925307).
文摘Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and microfluidics.However, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.
基金Basic Science Research Program of the National Research Foundation of Korea under Grant Nos.NRF-2020R1A6A1A03044977 and NRF2022R1A2C2004351。
文摘In this study, shaking table tests were performed to investigate the dynamic characteristics of a mold transformer. Based on the test results, rotary friction dampers were developed to mitigate the excessive lateral displacement that occurred along the direction of the weak stiffness axis of the mold transformer. In addition, shaking table tests were performed by attaching friction dampers to both sides of the mold transformer. Based on the shaking table test results, the natural frequency, mode vector, and damping ratio of the mold transformer were derived using the transfer function and half-power bandwidth. The test results indicated that the use of friction dampers can decrease the displacement and acceleration response of the mold transformer. Finally, dynamic structural models were established considering the component connectivity and mass distribution of the mold transformer. In addition, a numerical strategy was proposed to calibrate the stiffness coefficients of the mold transformer, thereby facilitating the relationship between generalized mass and stiffness. The results indicated that the analytical model based on the calibration strategy of stiffness coefficients can reasonably simulate the dynamic behavior of the mold transformer using friction dampers with regard to transfer function, displacement, and acceleration response.
基金supported by the National Natural Science Foundation of China(52273197 and 52333007)Shenzhen Key Laboratory of Functional Aggregate Materials(ZDSYS20211021111400001)+2 种基金the Science and Technology Plan of Shenzhen(JCYJ2021324134613038,JCYJ20220818103007014,KQTD20210811090142053,GJHZ20210705141810031)the Innovation and Technology Commission(ITC-CNERC14SC01)Tianjin Key Medical Discipline(Specialty)Construction Project.
文摘Luminescent nanoclusters(NCs)have attracted much attention because of their superior photophysical properties;however,the design of dynamic NCs with reversible structural change is highly challenging.Herein,we synthesize a kind of dynamic luminescent NCs through Schiff base crosslinking between triethylenetetramine(TETA)and tannic acid at room temperature.The proposed NCs have an excitation-independent blue emission,and the maximum emission is available at about 458 nm with two excitation centers.Furthermore,the crosslinking degree of the NCs can be effectively adjusted by TETA and their formation is a kineticcontrol process.Most importantly,the proposed NCs show a property of pHcontrolled reversible depolymerization and polymerization,accompanied by a cyclic“on-off-on”photoswitching,which is directly attributed to pH-stimulated reversible C=N bond cleavage and re-formation.Because of the reversible structure change properties,the dynamic NCs have been well used in reversible information encryption.This new finding provides not only us with a powerful strategy to study the structure–properties relationship of luminescent NCs but also a design idea for constructing smart optical nanomaterials.
文摘In recent years,the evolution of the community structure in social networks has gained significant attention.Due to the rapid and continuous evolution of real-world networks over time.This makes the process of identifying communities and tracking their topology changes challenging.To tackle these challenges,it is necessary to find efficient methodologies for analyzing the behavior patterns of dynamic communities.Several previous reviews have introduced algorithms and models for community detection.However,these methods have not been very accurate in identifying communities.Moreover,none of the reviewed papers made an apparent effort to link algorithms that can accurately detect dynamic communities.This review aims to present a taxonomy that shows several algorithms and methodologies for detecting dynamic communities.These algorithms are divided into four categories(heuristicand modularity-based,metaheuristic,deep learning,and hybrid deep learning).It encompasses the past five years and examines the advantages and disadvantages of conventional and recent methods.Currently,many efforts are utilizing deep learning to improve dynamic networks;however,the instability of the network during the training phase affects the model’s accuracy.However,this direction remains unexplored.This study presents a review that aims to tackle this issue.We discuss a research path that explores the integration of deep learning with heuristic,metaheuristic,and hybrid metaheuristic algorithms to facilitate the identification of communities in dynamic networks.This investigation examines how this mixture surpasses the constraints of singular methodologies,resulting in enhanced detection outcomes and enabling researchers to select the most suitable algorithms for their future research.
基金support from the National Natural Science Foundation of China(Grant Nos.52174123&52274222).
文摘This paper presents a framework for constructing surrogate models for sensitivity analysis of structural dynamics behavior.Physical models involving deformation,such as collisions,vibrations,and penetration,are devel-oped using the material point method.To reduce the computational cost of Monte Carlo simulations,response surface models are created as surrogate models for the material point system to approximate its dynamic behavior.An adaptive randomized greedy algorithm is employed to construct a sparse polynomial chaos expansion model with a fixed order,effectively balancing the accuracy and computational efficiency of the surrogate model.Based on the sparse polynomial chaos expansion,sensitivity analysis is conducted using the global finite difference and Sobol methods.Several examples of structural dynamics are provided to demonstrate the effectiveness of the proposed method in addressing structural dynamics problems.
基金the Natural Science Foundation of China(No.22301131)the Natural Science Foundation of Jiangsu Province(Nos.BK20220781,BK20240679)the National Key Research and Development Program of China(No.2024YFB3815700)are greatly acknowledged.
文摘Dynamic adaptability is a key feature in biological macromolecules,enabling selective binding and catalysis[1].From DNA supercoiling to enzyme conformational changes,biological systems have evolved intricate ways to dynamically adjust their structures to accommodate functional needs.Mimicking this adaptability in synthetic systems is an ongoing challenge in supramolecular chemistry.
文摘Cryo-electron microscopy makes use of transmission electron microscopy to image vitrified biological samples and reconstruct their three-dimensional structures from two-dimensional projections via computational approaches. After over40 years of development, this technique is now reaching its zenith and reforming the research paradigm of modern structural biology. It has been gradually taking over X-ray crystallography as the mainstream method. In this review, we briefly introduce the history of cryo-EM, recent technical development and its potential power to reveal dynamic structures. The technical barriers and possible approaches to tackle the upcoming challenges are discussed.
基金the National Natural Science Foundation of China(10377006).
文摘In the research of parachute, canopy inflation process modeling is one of the most complicated tasks. As canopy often experiences the largest deformations and loa-dings during a very short time, it is of great difficulty for theoretical analysis and experimental measurements. In this paper, aerodynamic equations and structural dynamics equations were developed for describing parachute opening process, and an iterative coupling solving strategy incorpo- rating the above equations was proposed for a small-scale, flexible and flat-circular parachute. Then, analyses were carried out for canopy geometry, time-dependent pressure difference between the inside and outside of the canopy, transient vortex around the canopy and the flow field in the radial plane as a sequence in opening process. The mechanism of the canopy shape development was explained from perspective of transient flow fields during the inflation process. Experiments of the parachute opening process were conducted in a wind tunnel, in which instantaneous shape of the canopy was measured by high velocity camera and the opening loading was measured by dynamometer balance. The theoretical predictions were found in good agreement with the experimental results, validating the proposed approach. This numerical method can improve the situation of strong dependence of parachute research on wind tunnel tests, and is of significance to the understanding of the mechanics of parachute inflation process.
基金co-supported by National Natural Science Foundation of China(Nos.51975124 and 51675179)Shanghai International Cooperation Project of One Belt and One Road of China(No.20110741700)Research Startup Fund of Fudan University(No.FDU38341)。
文摘For accurate Finite Element(FE)modeling for the structural dynamics of aeroengine casings,Parametric Modeling-based Model Updating Strategy(PM-MUS)is proposed based on efficient FE parametric modeling and model updating techniques regarding uncorrelated/correlated mode shapes.Casings structure is parametrically modeled by simplifying initial structural FE model and equivalently simulating mechanical characteristics.Uncorrelated modes between FE model and experiment are reasonably handled by adopting an objective function to recognize correct correlated modes pairs.The parametrized FE model is updated to effectively describe structural dynamic characteristics in respect of testing data.The model updating technology is firstly validated by the detailed FE model updating of one fixed–fixed beam structure in light of correlated/uncorrelated mode shapes and measured mode data.The PM-MUS is applied to the FE parametrized model updating of an aeroengine stator system(casings)which is constructed by the proposed parametric modeling approach.As revealed in this study,(A)the updated models by the proposed updating strategy and dynamic test data is accurate,and(B)the uncorrelated modes like close modes can be effectively handled and precisely identify the FE model mode associated the corresponding experimental mode,and(C)parametric modeling can enhance the dynamic modeling updating of complex structure in the accuracy of mode matching.The efforts of this study provide an efficient dynamic model updating strategy(PM-MUS)for aeroengine casings by parametric modeling and experimental test data regarding uncorrelated modes.
基金supported by National Natural Science Foundation of China(Grant No.10772060)Heilongjiang Provincial Natural Science Foundation with Excellent Young Investigators of China(GrantNo.JC2006-13)
文摘Spot weld models are widely used in finite element analysis(FEA)of automotive body in white(BIW)to predict static,dynamic,durability and other characteristics of automotive BIW.However,few researches are done on evaluation of the validity of these spot weld models in structural dynamic analysis of BIW.To evaluate the validity and accuracy of spot weld models in structural dynamic analysis of BIW,two object functions,error function and deviation function,are introduced innovatively.Modal analysis of Two-panel and Double-hat structures,which are the dominated structures in BIW,is conducted,and the values of these two object functions are obtained.Based on the values of object functions,the validity of these spot weld models are evaluated.It is found that the area contact method(ACM2)and weld element connection(CWELD)can give more precise prediction in modal analysis of these two classical structures,thus are more applicable to structural dynamic analysis of automotive BIW.Modal analysis of a classical BIW is performed,which further confirms this evaluation.The error function and deviation function proposed in this research can give guidance on the adaptability of spot weld models in structural dynamic analysis of BIW.And this evaluation method can also be adopted in evaluation of other finite element models in static,dynamic and other kinds of analysis for automotive structures.
