Many animals that use acoustic communication synchronize their mate attract!on signals: individuals precisely time their calls to overlap those of their neighbors. In contrast, synchrony in the mate attraction display...Many animals that use acoustic communication synchronize their mate attract!on signals: individuals precisely time their calls to overlap those of their neighbors. In contrast, synchrony in the mate attraction displays of species with visual/motion-based signals is rare. It has only been documented in five species of fiddler crabs. In all of them, small groups of males wave their single large claw in close synchrony. Here, I review what we know about synchrony in fiddler crabs, comparing the five species with each other to determine whether similar mechanisms and functions are comm on to all. I also propose future research questions that, if answered, would shed light on synchronous behavior in both visual and acoustic signallers.展开更多
Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and th...Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and there are methods that change curly or wavy hair into straight hair. Hair damage as a result of winding, combing, and using high-temperature hairdressing irons is also often seen. By using scanning electron micrographs (SEM) we showed broken hairs and hair damage caused by permanent wave solutions. The hair damage is obvious when comparisons are made with the condition of the hair surface, condition of the cuticle, etc. Hair swelling by permanent wave solutions, manipulations such as winding, etc., inadequate rinsing with water, procedures on injured hair at the outset, etc., are considered possible reasons for any of these types of injury.展开更多
Tujia Waving Dance, as an important part of culture, has drawn the attention of many scholars in sociology and ethnology and researched by them in recent years, with the results one after another. But from the perspec...Tujia Waving Dance, as an important part of culture, has drawn the attention of many scholars in sociology and ethnology and researched by them in recent years, with the results one after another. But from the perspective of sports and culture to observe and understand the Waving Dance, there are still not many learners and their analysis is limited to the discussions of the value of fitness and the recreational sports, but being ambiguous on the classification of the Waving Dance and its genes discussions, with some problems having big controversy. We can start from the basic shape of the Waving Dance to identify its dance category, to determine its basic factor, and to analyze the diversity value of the Waving Dance.展开更多
Hydrodynamic characteristics for two-dimensional flow around a waving plate are investigated. Under large Reynolds number approximation, the flow is assumed to be a combination of the outer potential flow and a thin v...Hydrodynamic characteristics for two-dimensional flow around a waving plate are investigated. Under large Reynolds number approximation, the flow is assumed to be a combination of the outer potential flow and a thin vortex layer, which consists of a boundary layer and a shed free shear layer. A nonlinear mathematical formulation for describing the outer unsteady potential flow coupled with an unsteady boundary layer equation for the inner viscous flow adjacent to the waving plate is developed. A semi-analytical method with a nonlinear Kutta condition imposed at the trailing edge is used to solve the velocity field of the outer flow and the evolution of wake vortex induced by a large-amplitude waving plate. The unsteady boundary layer equation is solved by extending Pohlhausen＇s method to its unsteady counterpart. The thrust and viscous drag coefficients, propulsive efficiency, and the pattern of wake vortex sheet are discussed.展开更多
The effect of the waving bed on the surface wave was investigated. The wave equation was reduced from the potential flow theory with the perturbation technique, and then was solved by using the pseudo-spectral method....The effect of the waving bed on the surface wave was investigated. The wave equation was reduced from the potential flow theory with the perturbation technique, and then was solved by using the pseudo-spectral method. The waterfall of the surface wave was simulated with the Matlab. It is shown that for the waving bed, an additional harmonic wave appears on the surface together with the solitary wave existing for the non-waving bed, and two kinds of waves do not interfere with each other. With the development of time, the waveform for the waving bed is kept invariable, and just the amplitude is reduced gradually. Wave-breaking phenomenon for the non-waving bed does not appear, so the waving bed seems useful to prevent the breaking of the wave.展开更多
This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solito...This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solitons propagating against a Painlevé wave background,in analogy to the established notion of elliptic solitons,which refers to solitons on an elliptic wave background.By employing a novel symmetry decomposition method aided by nonlocal residual symmetries,we explicitly construct (extended) Painlevé Ⅱ solitons for the Korteweg-de Vries equation and (extended) Painlevé Ⅳ solitons for the Boussinesq equation.展开更多
The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,an...The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples.展开更多
Offshore structures are constantly subjected to the complex forces of the marine environment,including wind,sea waves,currents,and seismic loadings.Among these,wind and sea wave forces persist throughout the structure...Offshore structures are constantly subjected to the complex forces of the marine environment,including wind,sea waves,currents,and seismic loadings.Among these,wind and sea wave forces persist throughout the structure’s lifetime.This study proposes a dynamic analysis approach that incorporates both time and frequency domain methods to investigate the structural responses of offshore structures under the combined effects of wind and wave forces.A wind wave-pier coupling dynamic model is first developed using a small-scale single pier,with corresponding dynamic equilibrium equations established.Fluctuating wind and sea waves are simulated using the weighted amplitude wave superposition(WAWS)method and linear superposition,respectively.Wind and wave load histories are then derived via Fourier transforms.The structural dynamic responses under different loading scenarios(wind only,wave only,and combined wind and wave)are analyzed using the Newmarkβmethod.Additionally,the effects of varying wind and wave parameters on structural responses are evaluated.The simulation results demonstrate that the structural responses to wind-wave coupling are smaller than the superimposed effects of wind and wave forces acting independently.When wind speeds are relatively low,wave forces dominate structural displacement and serve as the primary source of vibration.展开更多
Most existing path planning approaches rely on discrete expansions or localized heuristics that can lead to extended re-planning,inefficient detours,and limited adaptability to complex obstacle distributions.These iss...Most existing path planning approaches rely on discrete expansions or localized heuristics that can lead to extended re-planning,inefficient detours,and limited adaptability to complex obstacle distributions.These issues are particularly pronounced when navigating cluttered or large-scale environments that demand both global coverage and smooth trajectory generation.To address these challenges,this paper proposes a Wave Water Simulator(WWS)algorithm,leveraging a physically motivated wave equation to achieve inherently smooth,globally consistent path planning.In WWS,wavefront expansions naturally identify safe corridors while seamlessly avoiding local minima,and selective corridor focusing reduces computational overhead in large or dense maps.Comprehensive simulations and real-world validations-encompassing both indoor and outdoor scenarios-demonstrate that WWS reduces path length by 2%-13%compared to conventional methods,while preserving gentle curvature and robust obstacle clearance.Furthermore,WWS requires minimal parameter tuning across diverse domains,underscoring its broad applicability to warehouse robotics,field operations,and autonomous service vehicles.These findings confirm that the proposed wave-based framework not only bridges the gap between local heuristics and global coverage but also sets a promising direction for future extensions toward dynamic obstacle scenarios and multi-agent coordination.展开更多
Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the...Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz.展开更多
Studies of wave-current interactions are vital for the safe design of structures.Regular waves in the presence of uniform,linear shear,and quadratic shear currents are explored by the High-Level Green-Naghdi model in ...Studies of wave-current interactions are vital for the safe design of structures.Regular waves in the presence of uniform,linear shear,and quadratic shear currents are explored by the High-Level Green-Naghdi model in this paper.The five-point central difference method is used for spatial discretization,and the fourth-order Adams predictor-corrector scheme is employed for marching in time.The domain-decomposition method is applied for the wave-current generation and absorption.The effects of currents on the wave profile and velocity field are examined under two conditions:the same velocity of currents at the still-water level and the constant flow volume of currents.Wave profiles and velocity fields demonstrate substantial differences in three types of currents owing to the diverse vertical distribution of current velocity and vorticity.Then,loads on small-scale vertical cylinders subjected to regular waves and three types of background currents with the same flow volume are investigated.The maximum load intensity and load fluctuation amplitude in uniform,linear shear,and quadratic shear currents increase sequentially.The stretched superposition method overestimates the maximum load intensity and load fluctuation amplitude in opposing currents and underestimates these values in following currents.The stretched superposition method obtains a poor approximation for strong nonlinear waves,particularly in the case of the opposing quadratic shear current.展开更多
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin...This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.展开更多
Ultrasound neuromodulation shows promise for treating neurological disorders,but the underlying mechanisms remain unclear.Here,we developed an integrated surface acoustic wave(SAW)ultrasound chip enabling simultaneous...Ultrasound neuromodulation shows promise for treating neurological disorders,but the underlying mechanisms remain unclear.Here,we developed an integrated surface acoustic wave(SAW)ultrasound chip enabling simultaneous electrophysiological recording and Ca^(2+) imaging of cultured hippocampal neurons to investigate neuronal excitability and synaptic transmission during ultrasound stimulation.This study revealed,for the first time,three distinct neuronal response patterns induced by SAW ultrasound:an immediate response showing rapid activation,a delayed response exhibiting facilitation after several minutes,and a non-response maintaining baseline activity.Ultrasound stimulation increased action potential firing,enhanced excitatory postsynaptic currents,and elevated intracellular Ca^(2+) levels.These effects were dependent on extracellular Ca^(2+) influx and primarily dominated by L-type Ca^(2+) channels.Our findings suggest that individual neurons exhibit heterogeneous responses to SAW ultrasound stimulation based on their intracellular Ca^(2+) levels and L-type Ca^(2+) channel activity.This integrated approach provides new insights into the cellular mechanisms of ultrasound neuromodulation while highlighting the potential of SAW technology for precise,cell-type-specific neural control.展开更多
To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated in...To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated into a liquid fuel primarily composed of diethyl ether(DEE)and isopropyl nitrate(IPN).The explosion characteristics of different solid-liquid fuel-air-explosive(FAE)under unconfined conditions are investigated using a high-speed camera,infrared thermal imaging,and a pressure measurement system.Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation,with aluminum exhibiting the most pronounced effect.Fuel 5#(45.4 wt%DEE,9.2 wt%IPN,29.5 wt%Al,9.1 wt%B,6.8 wt%MgH_(2))exhibits superior explosion performance,achieving higher values of overpressure,impulse,and thermal radiation damage during the detonation stage compared to other fuels.However,Fuel 5#also displays faster decay rates,attributed to accelerated heat release rates induced by B and MgH_(2)powders.This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance,providing critical insights for optimizing composite fuel design.展开更多
The Kumkol Basin,situated in the northern margin of the Qinghai-Xizang Plateau,provides a unique window into understanding the dynamic mechanisms driving the plateau’s northern expansion.However,its formation and tec...The Kumkol Basin,situated in the northern margin of the Qinghai-Xizang Plateau,provides a unique window into understanding the dynamic mechanisms driving the plateau’s northern expansion.However,its formation and tectonic evolution remain poorly understood due to limited geophysical data in this region.In this study,we computed cross-correlations for the TT components of station-pairs with high signal-to-noise ratios to extract Love wave waveforms and further performed Lovewave ambient noise tomography to image the upper crustal shear-wave velocity structure of the Kumkol basin down to 10 km depth.Our seismic velocity model reveals that the Kumkol Basin has a sedimentary thickness exceeding 8 km,with its center located near the Arka Mountain on the southern side.This suggests that the basin was likely formed as a foreland basin in response to the uplift of the Qiman Tagh Mountain to the north.Additionally,integrated with seismic reflection data,our seismic velocity model images a detachment fault at the basin basement depth.We inferred that the Kumkol Anticlinorium at the basin’s center have been produced by multiple thrust faults converging into this detachment fault at 8–10 km depth following the Early to Middle Miocene uplift of the Qiman Tagh Mountain.This structural configuration indicates pulsed basinward deformation since the late Miocene,likely reflecting a tectonic regime shift from extrusion to distributed shortening in the northern Qinghai-Xizang Plateau.Our findings provide a high-resolution velocity model of the Kumkol Basin,offering critical insights into its structural evolution and supporting future resource exploration in this underexplored region.展开更多
The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbi...The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.展开更多
In manganese electrolysis,electrochemical oscillations and manganese dendrite growth are typical nonlinear phenomena critical for energy consumption reduction.Nonetheless,existing research lacks a deep understanding o...In manganese electrolysis,electrochemical oscillations and manganese dendrite growth are typical nonlinear phenomena critical for energy consumption reduction.Nonetheless,existing research lacks a deep understanding of their underlying mechanisms.In this study,we systematically explored the evolution of anode electrochemical oscillations during manganese electrolysis and designed a square wave circuit to effectively suppress oscillations and dendrite growth while reducing energy consumption.A novel four-dimensional differential equation was introduced to explore the internal dynamic mechanisms of typical nonlinear behaviors.The experimental results showed that while the evolutionary patterns of current and potential oscillation signals were consistent,their waveform directions were opposite.The square wave current effectively suppressed both electrochemical oscillations and the growth of manganese dendrites.Furthermore,compared to direct current electrolysis,the square wave current improved the current efficiency by 3.6%and reduced the energy consumption by 0.32 kW·h·kg^(−1).展开更多
Auroral kilometric radiation(AKR),a fundamental plasma emission in Earth's magnetosphere,exhibits three characteristic modes:the right-handed extraordinary(R-X),left-handed ordinary(L-O)and left-handed extraordina...Auroral kilometric radiation(AKR),a fundamental plasma emission in Earth's magnetosphere,exhibits three characteristic modes:the right-handed extraordinary(R-X),left-handed ordinary(L-O)and left-handed extraordinary(L-X)modes.The role of AKR in magnetosphere−ionosphere−atmosphere coupling depends sensitively on its wave mode.While previous studies have primarily focused on the dominant R-X mode,we present the first systematic identification of all three modes using a practical polarization analysis method based on Arase satellite observations.This method employs a spin-axis-relative Ratio:when the satellite's spin axis aligns with the background magnetic field,a positive(negative)Ratio indicates the right-handed(left-handed)polarization,with reversal under anti-parallel conditions.Combined polarization-frequency analysis reveals that R-X,L-O,and L-X modes can exist in both dayside and nightside regions,with power spectral densities up to 10^(-6)mV^(2)m^(-2)Hz^(-1).This study resolves long-standing ambiguities in AKR mode classification and has implications for understanding AKR-induced electron dynamics.展开更多
文摘Many animals that use acoustic communication synchronize their mate attract!on signals: individuals precisely time their calls to overlap those of their neighbors. In contrast, synchrony in the mate attraction displays of species with visual/motion-based signals is rare. It has only been documented in five species of fiddler crabs. In all of them, small groups of males wave their single large claw in close synchrony. Here, I review what we know about synchrony in fiddler crabs, comparing the five species with each other to determine whether similar mechanisms and functions are comm on to all. I also propose future research questions that, if answered, would shed light on synchronous behavior in both visual and acoustic signallers.
文摘Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and there are methods that change curly or wavy hair into straight hair. Hair damage as a result of winding, combing, and using high-temperature hairdressing irons is also often seen. By using scanning electron micrographs (SEM) we showed broken hairs and hair damage caused by permanent wave solutions. The hair damage is obvious when comparisons are made with the condition of the hair surface, condition of the cuticle, etc. Hair swelling by permanent wave solutions, manipulations such as winding, etc., inadequate rinsing with water, procedures on injured hair at the outset, etc., are considered possible reasons for any of these types of injury.
文摘Tujia Waving Dance, as an important part of culture, has drawn the attention of many scholars in sociology and ethnology and researched by them in recent years, with the results one after another. But from the perspective of sports and culture to observe and understand the Waving Dance, there are still not many learners and their analysis is limited to the discussions of the value of fitness and the recreational sports, but being ambiguous on the classification of the Waving Dance and its genes discussions, with some problems having big controversy. We can start from the basic shape of the Waving Dance to identify its dance category, to determine its basic factor, and to analyze the diversity value of the Waving Dance.
基金Project supported by the Innovation Project of the Chinese Academy of Sciences (Grant No. KJCX-SW-L04)the National Natural Science Foundation of China (Grant No.10332040)the Program of Hundred-Talent of the Chinese Academy of Sciences.
文摘Hydrodynamic characteristics for two-dimensional flow around a waving plate are investigated. Under large Reynolds number approximation, the flow is assumed to be a combination of the outer potential flow and a thin vortex layer, which consists of a boundary layer and a shed free shear layer. A nonlinear mathematical formulation for describing the outer unsteady potential flow coupled with an unsteady boundary layer equation for the inner viscous flow adjacent to the waving plate is developed. A semi-analytical method with a nonlinear Kutta condition imposed at the trailing edge is used to solve the velocity field of the outer flow and the evolution of wake vortex induced by a large-amplitude waving plate. The unsteady boundary layer equation is solved by extending Pohlhausen＇s method to its unsteady counterpart. The thrust and viscous drag coefficients, propulsive efficiency, and the pattern of wake vortex sheet are discussed.
基金Project supported by the National Nature Science Foundation of China (Grant No: 10272044), Research Fund for the Doctoral Program of Higher Education of China (Grant No: 20040079004) and the China Postdoctoral Science Foundation.
文摘The effect of the waving bed on the surface wave was investigated. The wave equation was reduced from the potential flow theory with the perturbation technique, and then was solved by using the pseudo-spectral method. The waterfall of the surface wave was simulated with the Matlab. It is shown that for the waving bed, an additional harmonic wave appears on the surface together with the solitary wave existing for the non-waving bed, and two kinds of waves do not interfere with each other. With the development of time, the waveform for the waving bed is kept invariable, and just the amplitude is reduced gradually. Wave-breaking phenomenon for the non-waving bed does not appear, so the waving bed seems useful to prevent the breaking of the wave.
基金supported by the National Natural Science Foundations of China (Grant Nos.12235007,12001424,12271324,and 12501333)the Natural Science Basic research program of Shaanxi Province (Grant Nos.2021JZ-21 and 2024JC-YBQN-0069)+3 种基金the China Postdoctoral Science Foundation (Grant Nos.2020M673332 and 2024M751921)the Fundamental Research Funds for the Central Universities (Grant No.GK202304028)the 2023 Shaanxi Province Postdoctoral Research Project (Grant No.2023BSHEDZZ186)Xi’an University,Xi’an Science and Technology Plan Wutongshu Technology Transfer Action Innovation Team(Grant No.25WTZD07)。
文摘This letter introduces the novel concept of Painlevé solitons—waves arising from the interaction between Painlevé waves and solitons in integrable systems.Painlevé solitons can also be viewed as solitons propagating against a Painlevé wave background,in analogy to the established notion of elliptic solitons,which refers to solitons on an elliptic wave background.By employing a novel symmetry decomposition method aided by nonlocal residual symmetries,we explicitly construct (extended) Painlevé Ⅱ solitons for the Korteweg-de Vries equation and (extended) Painlevé Ⅳ solitons for the Boussinesq equation.
基金supported by the National Natural Science Foundation of China(Grant No.12172063).
文摘The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples.
基金Project(2022YFB2302700)supported by the National Key Research and Development Program of China。
文摘Offshore structures are constantly subjected to the complex forces of the marine environment,including wind,sea waves,currents,and seismic loadings.Among these,wind and sea wave forces persist throughout the structure’s lifetime.This study proposes a dynamic analysis approach that incorporates both time and frequency domain methods to investigate the structural responses of offshore structures under the combined effects of wind and wave forces.A wind wave-pier coupling dynamic model is first developed using a small-scale single pier,with corresponding dynamic equilibrium equations established.Fluctuating wind and sea waves are simulated using the weighted amplitude wave superposition(WAWS)method and linear superposition,respectively.Wind and wave load histories are then derived via Fourier transforms.The structural dynamic responses under different loading scenarios(wind only,wave only,and combined wind and wave)are analyzed using the Newmarkβmethod.Additionally,the effects of varying wind and wave parameters on structural responses are evaluated.The simulation results demonstrate that the structural responses to wind-wave coupling are smaller than the superimposed effects of wind and wave forces acting independently.When wind speeds are relatively low,wave forces dominate structural displacement and serve as the primary source of vibration.
文摘Most existing path planning approaches rely on discrete expansions or localized heuristics that can lead to extended re-planning,inefficient detours,and limited adaptability to complex obstacle distributions.These issues are particularly pronounced when navigating cluttered or large-scale environments that demand both global coverage and smooth trajectory generation.To address these challenges,this paper proposes a Wave Water Simulator(WWS)algorithm,leveraging a physically motivated wave equation to achieve inherently smooth,globally consistent path planning.In WWS,wavefront expansions naturally identify safe corridors while seamlessly avoiding local minima,and selective corridor focusing reduces computational overhead in large or dense maps.Comprehensive simulations and real-world validations-encompassing both indoor and outdoor scenarios-demonstrate that WWS reduces path length by 2%-13%compared to conventional methods,while preserving gentle curvature and robust obstacle clearance.Furthermore,WWS requires minimal parameter tuning across diverse domains,underscoring its broad applicability to warehouse robotics,field operations,and autonomous service vehicles.These findings confirm that the proposed wave-based framework not only bridges the gap between local heuristics and global coverage but also sets a promising direction for future extensions toward dynamic obstacle scenarios and multi-agent coordination.
基金support provided by the Center for Fabrication and Application of Electronic Materials at Dokuz Eylül University,Türkiye。
文摘Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz.
基金Supported by the Development and Application Project of Ship CAE Software.
文摘Studies of wave-current interactions are vital for the safe design of structures.Regular waves in the presence of uniform,linear shear,and quadratic shear currents are explored by the High-Level Green-Naghdi model in this paper.The five-point central difference method is used for spatial discretization,and the fourth-order Adams predictor-corrector scheme is employed for marching in time.The domain-decomposition method is applied for the wave-current generation and absorption.The effects of currents on the wave profile and velocity field are examined under two conditions:the same velocity of currents at the still-water level and the constant flow volume of currents.Wave profiles and velocity fields demonstrate substantial differences in three types of currents owing to the diverse vertical distribution of current velocity and vorticity.Then,loads on small-scale vertical cylinders subjected to regular waves and three types of background currents with the same flow volume are investigated.The maximum load intensity and load fluctuation amplitude in uniform,linear shear,and quadratic shear currents increase sequentially.The stretched superposition method overestimates the maximum load intensity and load fluctuation amplitude in opposing currents and underestimates these values in following currents.The stretched superposition method obtains a poor approximation for strong nonlinear waves,particularly in the case of the opposing quadratic shear current.
基金supported by the National Natural Science Foundation of China(Grant No.42261134532,42405059,and U2342212)。
文摘This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.
基金supported by the National Key Research&Development Program of China(2022YFC3602700,2022YFC3602702)the Science and Technology Innovation 2030-Brain Science and Brain-Inspired Intelligence Project(2021ZD0201301)+2 种基金the National Natural Science Foundation of China(12034015,62088101,32170688,323B1004)Program of Shanghai Academic Research Leader(21XD1403600)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100,2018SHZDZX01).
文摘Ultrasound neuromodulation shows promise for treating neurological disorders,but the underlying mechanisms remain unclear.Here,we developed an integrated surface acoustic wave(SAW)ultrasound chip enabling simultaneous electrophysiological recording and Ca^(2+) imaging of cultured hippocampal neurons to investigate neuronal excitability and synaptic transmission during ultrasound stimulation.This study revealed,for the first time,three distinct neuronal response patterns induced by SAW ultrasound:an immediate response showing rapid activation,a delayed response exhibiting facilitation after several minutes,and a non-response maintaining baseline activity.Ultrasound stimulation increased action potential firing,enhanced excitatory postsynaptic currents,and elevated intracellular Ca^(2+) levels.These effects were dependent on extracellular Ca^(2+) influx and primarily dominated by L-type Ca^(2+) channels.Our findings suggest that individual neurons exhibit heterogeneous responses to SAW ultrasound stimulation based on their intracellular Ca^(2+) levels and L-type Ca^(2+) channel activity.This integrated approach provides new insights into the cellular mechanisms of ultrasound neuromodulation while highlighting the potential of SAW technology for precise,cell-type-specific neural control.
基金supported by the National Natural Science Foundation of China(Grant No.12402432)Natural Science Foundation of Jiangsu Province of China(Grant No.BK20230936)Graduate Education and Teaching Reform Project of Nanjing University of Science and Technology(Grant No.KT2024_C14)。
文摘To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated into a liquid fuel primarily composed of diethyl ether(DEE)and isopropyl nitrate(IPN).The explosion characteristics of different solid-liquid fuel-air-explosive(FAE)under unconfined conditions are investigated using a high-speed camera,infrared thermal imaging,and a pressure measurement system.Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation,with aluminum exhibiting the most pronounced effect.Fuel 5#(45.4 wt%DEE,9.2 wt%IPN,29.5 wt%Al,9.1 wt%B,6.8 wt%MgH_(2))exhibits superior explosion performance,achieving higher values of overpressure,impulse,and thermal radiation damage during the detonation stage compared to other fuels.However,Fuel 5#also displays faster decay rates,attributed to accelerated heat release rates induced by B and MgH_(2)powders.This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance,providing critical insights for optimizing composite fuel design.
基金funded by the National Natural Science Foundation of China(No.42274066),the Second Qinghai-Xizang Plateau Scientific Expedition and Research Program(STEP)(No.2019Q ZKK0701).
文摘The Kumkol Basin,situated in the northern margin of the Qinghai-Xizang Plateau,provides a unique window into understanding the dynamic mechanisms driving the plateau’s northern expansion.However,its formation and tectonic evolution remain poorly understood due to limited geophysical data in this region.In this study,we computed cross-correlations for the TT components of station-pairs with high signal-to-noise ratios to extract Love wave waveforms and further performed Lovewave ambient noise tomography to image the upper crustal shear-wave velocity structure of the Kumkol basin down to 10 km depth.Our seismic velocity model reveals that the Kumkol Basin has a sedimentary thickness exceeding 8 km,with its center located near the Arka Mountain on the southern side.This suggests that the basin was likely formed as a foreland basin in response to the uplift of the Qiman Tagh Mountain to the north.Additionally,integrated with seismic reflection data,our seismic velocity model images a detachment fault at the basin basement depth.We inferred that the Kumkol Anticlinorium at the basin’s center have been produced by multiple thrust faults converging into this detachment fault at 8–10 km depth following the Early to Middle Miocene uplift of the Qiman Tagh Mountain.This structural configuration indicates pulsed basinward deformation since the late Miocene,likely reflecting a tectonic regime shift from extrusion to distributed shortening in the northern Qinghai-Xizang Plateau.Our findings provide a high-resolution velocity model of the Kumkol Basin,offering critical insights into its structural evolution and supporting future resource exploration in this underexplored region.
基金supported by the National Natural Science Foundation of China(No.52436008)the Inner Mongolia Science and Technology Projects,China(Nos.JMRHZX20210003 and 2023YFCY0009)+3 种基金the Huaneng Group Co Ltd.,China(No.HNKJ23-H50)the National Natural Science Foundation of China(No.22408044)the China Postdoctoral Science Foundation(No.2024M761877)the National Key R&D Program of China(No.SQ2024YFD2200039)。
文摘The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.
基金support from the Fundamental Research Funds for the Central Universities(2022CDJQY-005,2024CDJXY010)the Guangxi Science and Technology Program(AB24010229)is greatly acknowledged.
文摘In manganese electrolysis,electrochemical oscillations and manganese dendrite growth are typical nonlinear phenomena critical for energy consumption reduction.Nonetheless,existing research lacks a deep understanding of their underlying mechanisms.In this study,we systematically explored the evolution of anode electrochemical oscillations during manganese electrolysis and designed a square wave circuit to effectively suppress oscillations and dendrite growth while reducing energy consumption.A novel four-dimensional differential equation was introduced to explore the internal dynamic mechanisms of typical nonlinear behaviors.The experimental results showed that while the evolutionary patterns of current and potential oscillation signals were consistent,their waveform directions were opposite.The square wave current effectively suppressed both electrochemical oscillations and the growth of manganese dendrites.Furthermore,compared to direct current electrolysis,the square wave current improved the current efficiency by 3.6%and reduced the energy consumption by 0.32 kW·h·kg^(−1).
基金supported by the National Natural Science Foundation of China(Grants 42374215,42230209,42374199,42304183,42422406,42174185,72061147004 and 72342001)the Science and Technology Development Fund,Macao SAR(File no.0042/2024/RIA1 and 0008/2024/AKP)+1 种基金the Natural Science Foundation of Hunan Province(Grant 2023JJ20038)the Research Project of Science and Technology of Hunan Province(2025JJ10009,2022RC4025,2025QK1004,2023JJ50312,2023JJ50010 and 2024RC9012).
文摘Auroral kilometric radiation(AKR),a fundamental plasma emission in Earth's magnetosphere,exhibits three characteristic modes:the right-handed extraordinary(R-X),left-handed ordinary(L-O)and left-handed extraordinary(L-X)modes.The role of AKR in magnetosphere−ionosphere−atmosphere coupling depends sensitively on its wave mode.While previous studies have primarily focused on the dominant R-X mode,we present the first systematic identification of all three modes using a practical polarization analysis method based on Arase satellite observations.This method employs a spin-axis-relative Ratio:when the satellite's spin axis aligns with the background magnetic field,a positive(negative)Ratio indicates the right-handed(left-handed)polarization,with reversal under anti-parallel conditions.Combined polarization-frequency analysis reveals that R-X,L-O,and L-X modes can exist in both dayside and nightside regions,with power spectral densities up to 10^(-6)mV^(2)m^(-2)Hz^(-1).This study resolves long-standing ambiguities in AKR mode classification and has implications for understanding AKR-induced electron dynamics.
