A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stre...A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.展开更多
Nanodroplet impact on nanoscale material interfaces is widely involved in nanoscience and nanotechnology,affecting the technical reliability through complicated liquid‒solid interaction force,that is,the droplet impac...Nanodroplet impact on nanoscale material interfaces is widely involved in nanoscience and nanotechnology,affecting the technical reliability through complicated liquid‒solid interaction force,that is,the droplet impact force.However,our understanding of the nanodroplet impact force is still blank.Herein,we reveal that the nanoscale size(∼10 nm)and high impact velocity(>100 m/s)of nanodroplets lead to unique characteristics of impact force,significantly differing from those ofmacrodroplets(∼1 mm).The nanodroplet impact force profile holds a single-peak feature,which is independent of droplet parameters and material wettability.The significant water-hammer pressure induces the abnormal rising of impact force,yielding unexpectedly high peak values governed by the Mach number(more than 10 orders of magnitude higher than droplet gravity).Our findings of droplet impact force at the nanoscale reveal the potential challenge of the damage of material surfaces by nanodroplet impact,highlighting one crucial factor for advancing nanolithography and nanoprinting.展开更多
The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input mult...The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input multi-output,nonlinearity,and strong coupling presents significant challenges.The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality.Hence,a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force.Firstly,an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint.Then,the posture error is integrated into the online position axis control to ensure tracking the ideal posture,while the force control axis compensates for posture deviation by minimizing internal force,thereby achieving high precision and low internal force.Finally,the effectiveness was demonstrated through experiments.The root mean square errors of orientation and position are 104 rad and 0.1 mm,respectively.A reduction in internal force can range from 10.96%to 57.4%compared to the traditional method.Key points'max position error is decreased from 0.32 mm to 0.18 mm,satisfying the 0.5 mm tolerance.Therefore,the proposed method will help promote the development of high-performance manufacturing.展开更多
Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in...Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in-situ observed results of the collision process of different types of inclusions on the surface of the molten steel.The developed model can be used to calculate the attraction of inclusions on the surface of the molten steel including Al_(2)O_(3)MgO,SiO_(2),etc.展开更多
Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
Systematic understanding of the interaction between cells and their microenvironment is of wide interest.To investigate this interaction,a flexible micropillar array device integrating dual functions of cell behavior ...Systematic understanding of the interaction between cells and their microenvironment is of wide interest.To investigate this interaction,a flexible micropillar array device integrating dual functions of cell behavior regulation and adhesion measurement is developed.Micropillar arrays with high and low densities are designed to explore the role of substrate topography in the behavior of human bone marrow mesenchymal stem cells.In addition,a method is established for quantifying weak cell adhesion forces on the basis of micropillar deflections.The results show that cell cytoplasmic adhesion is greater on a low-density micropillar array than that on a high-density array and is localized mainly in the perinuclear region of the cytoplasm rather than in pseudopods.It is also found that the micropillar array topography facilitates the oriented spreading of cell morphology and pseudopod formation,and a reduction in focal adhesion aggregation and F-actin polarization compared with a flat substrate.Notably,cells cultured on a low-density micropillar array exhibited a higher number of pseudopods,stronger adhesion forces,and greater stiffness compared with those on a high-density array.In summary,this work employs an adhesion force sensor,immunofluorescence staining,and atomic force microscopy to investigate the mechanical properties of cells and elucidate the mechanisms by which micropillar topographical cues regulate the adhesion of mesenchymal stem cells to the substrate.The micropillar array force sensor developed in this study provides an effective tool for simultaneously modulating cell behavior and quantifying adhesion forces,offering valuable insights for biomechanical research.展开更多
In the context of the coordinated pursuit of"carbon peak and neutrality"objectives,alongside the strategy to establish a robust agricultural nation,the economic and social development of rural areas is under...In the context of the coordinated pursuit of"carbon peak and neutrality"objectives,alongside the strategy to establish a robust agricultural nation,the economic and social development of rural areas is undergoing a profound paradigm shift.The traditional rural division of labor pattern,which depends on tangible factors such as land,labor,and capital,has increasingly encountered developmental challenges characterized by diminishing marginal returns and a detrimental cycle of internal competition.The new quality productive force,centered on data,algorithms,green technologies,bioengineering,and clean energy,offers a potential pathway for the rural division of labor system to overcome the"low-level equilibrium".This force is characterized by attributes such as non-exclusivity,replicability,network collaboration,and ecological compatibility.This paper develops a three-dimensional collaborative analytical framework encompassing"technology,institution,and culture".It systematically elucidates the internal logic by which new quality productive forces drive the transformation of the rural division of labor from"quantitative factor matching"to"qualitative structural reorganization"through three principal mechanisms:technology embedding,institutional reconstruction,and cultural coupling.Furthermore,the study proposes corresponding policy recommendations,thereby offering theoretical insights to support the modernization of China s agriculture and rural areas,as well as the development of a strong agricultural country.展开更多
Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to smal...Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to small particles within the dipole regime or specific light fields,thereby lacking universality and sometimes leading to ambiguity.To overcome these limitations,we establish a fully analytical and comprehensive framework for optical force/torque based on the Cartesian multipole expansion theory,which is applicable to arbitrary-sized bi-isotropic(chiral)spherical particles immersed in arbitrary monochromatic optical fields.Rigorous expressions are thus derived,which explicitly bridge the optical force/torque with particle-propertydependent coefficients and“force/torque source”quantities characterizing the incident light structures.Such quantities identify the ultimate physical origins of optical force/torque and are systematically classified into four categories based on their parity(P)and duality(D)symmetries.Each category interacts selectively with particles exhibiting specific P and D(a)symmetries,thus inducing distinct optical forces or torques with characteristic physical behaviors.This classification establishes the mutual symmetry-breaking criteria necessary for both particles and light beams to generate optical force/torque,offering a physics-based roadmap for engineering optical manipulations such as chirality sorting,light-driven micromotors,and beyond.展开更多
We explore the potential of conducting an experiment in a low Earth orbit spacecraft and using the Earth as a spin and mass source to constrain beyond-the-standard-model(BSM)long-range spin-and velocity-dependent inte...We explore the potential of conducting an experiment in a low Earth orbit spacecraft and using the Earth as a spin and mass source to constrain beyond-the-standard-model(BSM)long-range spin-and velocity-dependent interactions,which are mediated by the exchange of an ultralight(m_(Z')<10^(-10)eV)or massless intermediate vector boson.The high speed of low-Earth-orbit spacecraft can enhance their sensitivity to velocity-dependent interactions.This periodicity enables efficient signal extraction from background noise,thereby improving the accuracy of the experiment.Combining these advantages,we theoretically demonstrate that the novel spacecraft-Earth model can improve the existing bounds on these exotic interactions by up to three orders of magnitude using the China Space Station(CSS)as a representative low-Earthorbit carrier.If successfully implemented,this model may provide an innovative strategy for detecting ultralight dark matter and yield tighter constraints on certain coupling constants of exotic interactions.展开更多
Manned aerial vehicle-unmanned aerial vehicle(MAV-UAV)combat organization is a MAV-UAV combat collective formed from the perspective of organization design theory and methodology,and the generation of force formation ...Manned aerial vehicle-unmanned aerial vehicle(MAV-UAV)combat organization is a MAV-UAV combat collective formed from the perspective of organization design theory and methodology,and the generation of force formation plan is a key step in the organizational planning.Based on the description of the problem and the definition of organizational elements,the matching model of platform-target attack wave is constructed to minimize the redundancy of command and decision-making capability,resource capability and the number of platforms used.Based on the non-dominated sorting genetic algorithmⅢ(NSGA-Ⅲ)framework,which includes encoding/decoding method and constraint handling method,the generation model of organizational force formation plan is solved,and the effectiveness and superiority of the algorithm are verified by simulation experiments.展开更多
The rapid development of new-quality productive forces(NQPF)has intensified the demand for high-level innovative talent.As a representative of NQPF,generative artificial intelligence(GenAI)offers powerful tools to res...The rapid development of new-quality productive forces(NQPF)has intensified the demand for high-level innovative talent.As a representative of NQPF,generative artificial intelligence(GenAI)offers powerful tools to reshape talent cultivation but also presents significant challenges,including skill hollowing,ethical risks,and a growing disconnect between education and industry needs.Currently,graduate-level software engineering education struggles with outdated curricula and insufficient alignment with practical demands.In this paper,we propose a dual-core collaborative framework driven by“GenAI technology”and“industry demand”.Under this framework,we design a four-dimensional capability development path to enhance graduate students’innovation in software engineering practice.This path focuses on①scientific research innovation,②engineering problem-solving,③cross-domain collaborative evolution,and④ethical risk governance.The proposed approach promotes a shift from traditional knowledge transfer to human-machine collaborative innovation,aligning talent cultivation with the demands of the NQPF.展开更多
Against the backdrop of profound restructuring in the global industrial and supply chains,data elements have emerged as a critical force driving the transformation of enterprises'new quality productive forces.To a...Against the backdrop of profound restructuring in the global industrial and supply chains,data elements have emerged as a critical force driving the transformation of enterprises'new quality productive forces.To address the ambiguity surrounding its micro-level empowerment mechanism,this paper empirically examines the impact of data elements on enterprises'new quality productive forces and its transmission channels using panel data of Chinese A-share listed firms from 2014 to 2023.The results show that data elements significantly improve the level of enterprises'new quality productive forces.Heterogeneity analysis indicates that this promotional effect is more pronounced in non-state-owned enterprises,large-scale enterprises,and low-leverage enterprises.Mechanism tests confirm that data elements empower new quality productive forces through three paths:enhancing enterprise innovation capability,improving internal operational efficiency,and promoting inter-firm collaboration efficiency.This study provides empirical evidence for understanding the micro-level empowerment logic of data elements and offers theoretical references and practical implications for advancing the deep integration of the digital economy and the real economy.展开更多
Correction to:Nuclear Science and Techniques(2025)36:111 https://doi.org/10.1007/s41365-025-01681-9.In the sentence beginning‘The weights of the parameters used for the…’in this article,the text‘RCSs’should have ...Correction to:Nuclear Science and Techniques(2025)36:111 https://doi.org/10.1007/s41365-025-01681-9.In the sentence beginning‘The weights of the parameters used for the…’in this article,the text‘RCSs’should have read‘SCRs’.In Table 7 of this article,the column header ρ_fuel was incorrect and should have read CPv_fuel.For completeness and transparency,the old incorrect version and the corrected version of Table 7 are displayed below.展开更多
Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properti...Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation.展开更多
Driven by technological innovation and the innovative allocation of production factors,new quality productive forces(NQPFs)are a key breakthrough and core element propelling China’s transition from a major agricultur...Driven by technological innovation and the innovative allocation of production factors,new quality productive forces(NQPFs)are a key breakthrough and core element propelling China’s transition from a major agricultural country to an advanced agricultural nation.At its core,agricultural modernization represents a frontier shift in agricultural development-a dynamic evolution of productive forces across technological forms,farmer demographics,industrial structures,and urban-rural relations.NQPFs drive the high-quality,integrated development of agricultural modernization through agricultural technological innovation,green and low-carbon practices,and the enhancement of all production factors.As NQPFs evolve and agricultural modernization advances,we must address constraints stemming from gaps in technology,models,resources,and talent.Furthermore,we must foster deep integration among industry,research,and education to develop new pathways for industrial upgrading,promote green and efficient agricultural development,and bridge existing technological gaps.These collective efforts are crucial for accelerating the high-quality development of agricultural modernization.展开更多
Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive ...Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.展开更多
Astronomical extreme events or phenomena include black holes as well as nebulae systems that resemble the Milky Way. Meteorological extreme events or phenomena include tornadoes and tropical cyclones. The new high ene...Astronomical extreme events or phenomena include black holes as well as nebulae systems that resemble the Milky Way. Meteorological extreme events or phenomena include tornadoes and tropical cyclones. The new high energy state of matter expanding outwards by spin jets from the two poles of an astronomical black hole, the new high energy state of matter in a funnel-shaped vortex showed a meteorological tornado expanding downwards from a rotated disk of cumulonimbus clouds, the new high energy state of matter in a tropical cyclone and the new high energy state of a nebulae system converging celestial materials are phenomena across disciplines and multiple time-space scales that have not yet been physically explained. In this paper, the theory of orthogonal collision in the rotational contraction continuum is used to unify the understanding of diverse extreme events or phenomena through a single dynamical mechanism, offering insights into natural processes across disciplines. In the field of astronomy, the orthogonal collision of two-beam rotating and contracting particles or stars associated with centripetal forces forms a new high-energy state of matter at the collision point and the new high-energy particles have expanding forces outward to both sides of the collision plane. In the field of meteorology, the orthogonal collision of multiple horizontally rotating and contracting airflows associated with centripetal forces forms a new high energy state of matter at the collision point as well as an updraft force and a downdraft force vertically. The updraft force and downdraft force formed by the collision of anomalous wet airflows in the lower atmosphere can well indicate tornado, thunderstorm and extreme precipitation. The orthogonal collision theory can be applied to explain new states of matter in disciplines from the astronomical scale to the meteorological scale and the Planck scale.展开更多
Soft robots,as a modern gateway to unlocking the mysteries of underwater realms,present new complexities.Modeling their behavior when in contact with external forces,whether point-based or distributed,is a primary cha...Soft robots,as a modern gateway to unlocking the mysteries of underwater realms,present new complexities.Modeling their behavior when in contact with external forces,whether point-based or distributed,is a primary challenge due to the nature of soft bodies.To obtain a holistic view of the system’s behavior determining the governing dynamics is deemed necessary.This paper proposes a new technique to simulate the dynamic lateral undulation of a soft robotic fish with a cable-driven soft tail.By integrating the rigid finite element method with rigid-body robotics,the model represents the undulation of a finite number of rigid elements connected through a set of torsional spring and damper.Instead of directly modeling external forces,we substitute equivalent joint torques into the system dynamics,allowing us to consider external effects without complicating the model.The resulting model yields valuable insights into the system’s behavior,including propulsive and lateral forces.A comparison with experimental results shows strong agreement,with a tip amplitude error of 10% at 0.8 Hz,5.25% at 1.6 Hz and 2.54%at 2.2 Hz flapping frequency.These findings illuminate the influence of lateral undulation on the overall dynamics,paving the way for fully autonomous robotic fish.展开更多
With the intensification of lunar exploration,the failure risk caused by the adsorption of lunar dust on the spacecraft surface cannot be ignored.Therefore,three types of typical spatial solid lubrication films,namely...With the intensification of lunar exploration,the failure risk caused by the adsorption of lunar dust on the spacecraft surface cannot be ignored.Therefore,three types of typical spatial solid lubrication films,namely polytetrafluoroethylene(PTFE),amorphous carbon(a-C)and molybdenum disulfide(MoS2),were prepared as test samples.Firstly,the surface free energy parameters of the material were measured using a contact Angle measuring instrument.At the same time,atomic force microscopy(AFM)was used to quantify the adhesion of the film samples based on the lunar dust micro-adsorption model.In order to investigate the influence of the test environment,the environmental pressure was adjusted to normal pressure environment and high vacuum environment with a vacuum degree of 10−6 Pa for testing.The results indicate a positive correlation between surface energy and adhesion.As surface energy increases,molecules tend to move closer,forming a stronger attraction and thus enhancing surface adhesion.In addition,AFM was used to measure the adhesion force under atmospheric pressure and vacuum conditions,revealing that parameters measured in atmospheric environment were generally higher than those measured in vacuum,which effectively verified the existence of capillary force in the microscopic adsorption model and its influence on the adhesion effect.Through the test comparison of three groups of typical solid lubricating films,it is found that MoS2 has a lower adhesion effect than the other two groups of films,which can effectively reduce the adhesion phenomenon of lunar dust on the surface of the material,and provide suitable materials for future lunar exploration and manned lunar missions.展开更多
Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile ...Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile sensors,accurately decoupling signals—specifically separating forces from directional orientation and temperature—remains a challenge thus resulting in failure to meet the advanced application requirements of robots.This study proposes,F3T,a multilayer soft sensor unit designed to achieve isolated measurements and mathematical decoupling of normal pressure,omnidirectional tangential forces,and temperature.We developed a circular coaxial magnetic film featuring a floating mount multilayer capacitor that facilitated the physical decoupling of normal and tangential forces in all directions.Additionally,we incorporated an ion gel-based temperature-sensing film into the tactile sensor.The proposed sensor was resilient to external pressures and deformations,and could measure temperature and significantly eliminate capacitor errors induced by environmental temperature changes.In conclusion,our novel design allowed for the decoupled measurement of multiple signals,laying the foundation for advancements in high-level robotic motion control,autonomous decision-making,and task planning.展开更多
基金Project(52078129)supported by the National Natural Science Foundation of ChinaProject(MTF2023009)supported by the Open Project of Key Laboratory of Transport Industry of Comprehensive Transportation Theory(Nanjing Modern Multimodal Transportation Laboratory),ChinaProject(2242024K40037)supported by the Fundamental Research Funds for the Central Universities,China。
文摘A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.
基金the Beijing Nova Program(no.20240484595)the National Natural Science Foundation of China(no.52406104).
文摘Nanodroplet impact on nanoscale material interfaces is widely involved in nanoscience and nanotechnology,affecting the technical reliability through complicated liquid‒solid interaction force,that is,the droplet impact force.However,our understanding of the nanodroplet impact force is still blank.Herein,we reveal that the nanoscale size(∼10 nm)and high impact velocity(>100 m/s)of nanodroplets lead to unique characteristics of impact force,significantly differing from those ofmacrodroplets(∼1 mm).The nanodroplet impact force profile holds a single-peak feature,which is independent of droplet parameters and material wettability.The significant water-hammer pressure induces the abnormal rising of impact force,yielding unexpectedly high peak values governed by the Mach number(more than 10 orders of magnitude higher than droplet gravity).Our findings of droplet impact force at the nanoscale reveal the potential challenge of the damage of material surfaces by nanodroplet impact,highlighting one crucial factor for advancing nanolithography and nanoprinting.
基金co-supported by the National Natural Science Foundation of China(No.52125504)the Liaoning Revitalization Talents Program(No.XLYC2202017)Dalian Support Policy Project for Innovation of Technological Talents(No.2023RG001)。
文摘The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input multi-output,nonlinearity,and strong coupling presents significant challenges.The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality.Hence,a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force.Firstly,an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint.Then,the posture error is integrated into the online position axis control to ensure tracking the ideal posture,while the force control axis compensates for posture deviation by minimizing internal force,thereby achieving high precision and low internal force.Finally,the effectiveness was demonstrated through experiments.The root mean square errors of orientation and position are 104 rad and 0.1 mm,respectively.A reduction in internal force can range from 10.96%to 57.4%compared to the traditional method.Key points'max position error is decreased from 0.32 mm to 0.18 mm,satisfying the 0.5 mm tolerance.Therefore,the proposed method will help promote the development of high-performance manufacturing.
基金support from the National Natural Science Foundation of China(Grant No.U22A20171)the National Key Research and Development Program Project(2023YFB3709901)+3 种基金the China Baowu Low Carbon Metallurgical Innovation Fund(BWLCF202315)the Pangang-USTB Vanadium and Titanium Research Institute Research Projectthe High Steel Center(HSC)at North China University of TechnologyYanshan University and University of Science and Technology Beijing,China.
文摘Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in-situ observed results of the collision process of different types of inclusions on the surface of the molten steel.The developed model can be used to calculate the attraction of inclusions on the surface of the molten steel including Al_(2)O_(3)MgO,SiO_(2),etc.
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
基金supported by the National Natural Science Foundation of China(Grant No.32371471).
文摘Systematic understanding of the interaction between cells and their microenvironment is of wide interest.To investigate this interaction,a flexible micropillar array device integrating dual functions of cell behavior regulation and adhesion measurement is developed.Micropillar arrays with high and low densities are designed to explore the role of substrate topography in the behavior of human bone marrow mesenchymal stem cells.In addition,a method is established for quantifying weak cell adhesion forces on the basis of micropillar deflections.The results show that cell cytoplasmic adhesion is greater on a low-density micropillar array than that on a high-density array and is localized mainly in the perinuclear region of the cytoplasm rather than in pseudopods.It is also found that the micropillar array topography facilitates the oriented spreading of cell morphology and pseudopod formation,and a reduction in focal adhesion aggregation and F-actin polarization compared with a flat substrate.Notably,cells cultured on a low-density micropillar array exhibited a higher number of pseudopods,stronger adhesion forces,and greater stiffness compared with those on a high-density array.In summary,this work employs an adhesion force sensor,immunofluorescence staining,and atomic force microscopy to investigate the mechanical properties of cells and elucidate the mechanisms by which micropillar topographical cues regulate the adhesion of mesenchymal stem cells to the substrate.The micropillar array force sensor developed in this study provides an effective tool for simultaneously modulating cell behavior and quantifying adhesion forces,offering valuable insights for biomechanical research.
基金Supported by Key Project of Jiangsu Education Science Planning"Research on the Structural Adjustment of Higher Education in Jiangsu in the Context of High-Quality Economic Development"(B/2021/01/67).
文摘In the context of the coordinated pursuit of"carbon peak and neutrality"objectives,alongside the strategy to establish a robust agricultural nation,the economic and social development of rural areas is undergoing a profound paradigm shift.The traditional rural division of labor pattern,which depends on tangible factors such as land,labor,and capital,has increasingly encountered developmental challenges characterized by diminishing marginal returns and a detrimental cycle of internal competition.The new quality productive force,centered on data,algorithms,green technologies,bioengineering,and clean energy,offers a potential pathway for the rural division of labor system to overcome the"low-level equilibrium".This force is characterized by attributes such as non-exclusivity,replicability,network collaboration,and ecological compatibility.This paper develops a three-dimensional collaborative analytical framework encompassing"technology,institution,and culture".It systematically elucidates the internal logic by which new quality productive forces drive the transformation of the rural division of labor from"quantitative factor matching"to"qualitative structural reorganization"through three principal mechanisms:technology embedding,institutional reconstruction,and cultural coupling.Furthermore,the study proposes corresponding policy recommendations,thereby offering theoretical insights to support the modernization of China s agriculture and rural areas,as well as the development of a strong agricultural country.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204117,12564043,12174076,12074084,and 12074169)the Guangxi Science and Technology Project(Grant Nos.2023GXNSFFA026002,2024GXNSFBA010261,2021GXNSFDA196001,and AD23026117)+3 种基金the Open Project of State Key Laboratory of Surface Physics in Fudan University(Grant No.KF2022_15)the Guangdong Province Talent Recruitment Program(Grant No.2021QN02C103)supported by the Research Grants Council of Hong Kong(Grant Nos.16310422 and AoE/P-502/20)the Innovation Project of Guangxi Graduate Education(Grant No.11241018)。
文摘Understanding the complex interplay between structured light and particles is crucial for unlocking advanced optical manipulation techniques.However,existing theories for optical force/torque are often limited to small particles within the dipole regime or specific light fields,thereby lacking universality and sometimes leading to ambiguity.To overcome these limitations,we establish a fully analytical and comprehensive framework for optical force/torque based on the Cartesian multipole expansion theory,which is applicable to arbitrary-sized bi-isotropic(chiral)spherical particles immersed in arbitrary monochromatic optical fields.Rigorous expressions are thus derived,which explicitly bridge the optical force/torque with particle-propertydependent coefficients and“force/torque source”quantities characterizing the incident light structures.Such quantities identify the ultimate physical origins of optical force/torque and are systematically classified into four categories based on their parity(P)and duality(D)symmetries.Each category interacts selectively with particles exhibiting specific P and D(a)symmetries,thus inducing distinct optical forces or torques with characteristic physical behaviors.This classification establishes the mutual symmetry-breaking criteria necessary for both particles and light beams to generate optical force/torque,offering a physics-based roadmap for engineering optical manipulations such as chirality sorting,light-driven micromotors,and beyond.
基金partially supported by the National Key R&D Program of China (Grant No.2023YFA16067003)the National Science Foundation of China (Grant Nos.12435007 and 12522505)。
文摘We explore the potential of conducting an experiment in a low Earth orbit spacecraft and using the Earth as a spin and mass source to constrain beyond-the-standard-model(BSM)long-range spin-and velocity-dependent interactions,which are mediated by the exchange of an ultralight(m_(Z')<10^(-10)eV)or massless intermediate vector boson.The high speed of low-Earth-orbit spacecraft can enhance their sensitivity to velocity-dependent interactions.This periodicity enables efficient signal extraction from background noise,thereby improving the accuracy of the experiment.Combining these advantages,we theoretically demonstrate that the novel spacecraft-Earth model can improve the existing bounds on these exotic interactions by up to three orders of magnitude using the China Space Station(CSS)as a representative low-Earthorbit carrier.If successfully implemented,this model may provide an innovative strategy for detecting ultralight dark matter and yield tighter constraints on certain coupling constants of exotic interactions.
基金supported by the Natural Science Foundation of Shaanxi Province(2023-JC-QN-0728)the China Postdoctoral Science Foundation(2021M693942)。
文摘Manned aerial vehicle-unmanned aerial vehicle(MAV-UAV)combat organization is a MAV-UAV combat collective formed from the perspective of organization design theory and methodology,and the generation of force formation plan is a key step in the organizational planning.Based on the description of the problem and the definition of organizational elements,the matching model of platform-target attack wave is constructed to minimize the redundancy of command and decision-making capability,resource capability and the number of platforms used.Based on the non-dominated sorting genetic algorithmⅢ(NSGA-Ⅲ)framework,which includes encoding/decoding method and constraint handling method,the generation model of organizational force formation plan is solved,and the effectiveness and superiority of the algorithm are verified by simulation experiments.
基金supported in part by the Graduate Education Reform Research Project of Hubei University of Technology under Grant 2024YB003the Hubei University of Arts and Science,Teaching Research Project,under Grant JY2025018.
文摘The rapid development of new-quality productive forces(NQPF)has intensified the demand for high-level innovative talent.As a representative of NQPF,generative artificial intelligence(GenAI)offers powerful tools to reshape talent cultivation but also presents significant challenges,including skill hollowing,ethical risks,and a growing disconnect between education and industry needs.Currently,graduate-level software engineering education struggles with outdated curricula and insufficient alignment with practical demands.In this paper,we propose a dual-core collaborative framework driven by“GenAI technology”and“industry demand”.Under this framework,we design a four-dimensional capability development path to enhance graduate students’innovation in software engineering practice.This path focuses on①scientific research innovation,②engineering problem-solving,③cross-domain collaborative evolution,and④ethical risk governance.The proposed approach promotes a shift from traditional knowledge transfer to human-machine collaborative innovation,aligning talent cultivation with the demands of the NQPF.
文摘Against the backdrop of profound restructuring in the global industrial and supply chains,data elements have emerged as a critical force driving the transformation of enterprises'new quality productive forces.To address the ambiguity surrounding its micro-level empowerment mechanism,this paper empirically examines the impact of data elements on enterprises'new quality productive forces and its transmission channels using panel data of Chinese A-share listed firms from 2014 to 2023.The results show that data elements significantly improve the level of enterprises'new quality productive forces.Heterogeneity analysis indicates that this promotional effect is more pronounced in non-state-owned enterprises,large-scale enterprises,and low-leverage enterprises.Mechanism tests confirm that data elements empower new quality productive forces through three paths:enhancing enterprise innovation capability,improving internal operational efficiency,and promoting inter-firm collaboration efficiency.This study provides empirical evidence for understanding the micro-level empowerment logic of data elements and offers theoretical references and practical implications for advancing the deep integration of the digital economy and the real economy.
文摘Correction to:Nuclear Science and Techniques(2025)36:111 https://doi.org/10.1007/s41365-025-01681-9.In the sentence beginning‘The weights of the parameters used for the…’in this article,the text‘RCSs’should have read‘SCRs’.In Table 7 of this article,the column header ρ_fuel was incorrect and should have read CPv_fuel.For completeness and transparency,the old incorrect version and the corrected version of Table 7 are displayed below.
文摘Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation.
基金funded by grants from the General Project of the National Social Science Fund:“Research on the Interactive Mechanism of Migrant Workers Returning to Their Hometowns for Entrepreneurship and Rural Revitalization in the Major Labor Export Provinces”(20BJY136)General Project of Sichuan Provincial Philosophy and Social Science Fund:“The Era Significance,Growth Constraints,and Path Optimization of the New Agricultural Laborers from the Perspective of the New Quality Productive Forces”(SCJJ24ND065)Key Project of the Sichuan Academy of Social Sciences:“The Era Significance,Current Concerns,and Action Prospects of the New Agricultural Laborers from the Perspective of the New Quality Productive Forces”(24XD02).
文摘Driven by technological innovation and the innovative allocation of production factors,new quality productive forces(NQPFs)are a key breakthrough and core element propelling China’s transition from a major agricultural country to an advanced agricultural nation.At its core,agricultural modernization represents a frontier shift in agricultural development-a dynamic evolution of productive forces across technological forms,farmer demographics,industrial structures,and urban-rural relations.NQPFs drive the high-quality,integrated development of agricultural modernization through agricultural technological innovation,green and low-carbon practices,and the enhancement of all production factors.As NQPFs evolve and agricultural modernization advances,we must address constraints stemming from gaps in technology,models,resources,and talent.Furthermore,we must foster deep integration among industry,research,and education to develop new pathways for industrial upgrading,promote green and efficient agricultural development,and bridge existing technological gaps.These collective efforts are crucial for accelerating the high-quality development of agricultural modernization.
基金financially supported by the National Natural Science Foundation of China(Nos.52272160,U2330112,and 52002254)Sichuan Science and Technology Foundation(Nos.2020YJ0262,2021YFH0127,2022YFH0083,2022YFSY0045,and 2023YFSY0002)+1 种基金the Chunhui Plan of Ministry of Education,Fundamental Research Funds for the Central Universities,China(No.YJ201893)the Foundation of Key Laboratory of Lidar and Device,Sichuan Province,China(No.LLD2023-006)。
文摘Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.
文摘Astronomical extreme events or phenomena include black holes as well as nebulae systems that resemble the Milky Way. Meteorological extreme events or phenomena include tornadoes and tropical cyclones. The new high energy state of matter expanding outwards by spin jets from the two poles of an astronomical black hole, the new high energy state of matter in a funnel-shaped vortex showed a meteorological tornado expanding downwards from a rotated disk of cumulonimbus clouds, the new high energy state of matter in a tropical cyclone and the new high energy state of a nebulae system converging celestial materials are phenomena across disciplines and multiple time-space scales that have not yet been physically explained. In this paper, the theory of orthogonal collision in the rotational contraction continuum is used to unify the understanding of diverse extreme events or phenomena through a single dynamical mechanism, offering insights into natural processes across disciplines. In the field of astronomy, the orthogonal collision of two-beam rotating and contracting particles or stars associated with centripetal forces forms a new high-energy state of matter at the collision point and the new high-energy particles have expanding forces outward to both sides of the collision plane. In the field of meteorology, the orthogonal collision of multiple horizontally rotating and contracting airflows associated with centripetal forces forms a new high energy state of matter at the collision point as well as an updraft force and a downdraft force vertically. The updraft force and downdraft force formed by the collision of anomalous wet airflows in the lower atmosphere can well indicate tornado, thunderstorm and extreme precipitation. The orthogonal collision theory can be applied to explain new states of matter in disciplines from the astronomical scale to the meteorological scale and the Planck scale.
文摘Soft robots,as a modern gateway to unlocking the mysteries of underwater realms,present new complexities.Modeling their behavior when in contact with external forces,whether point-based or distributed,is a primary challenge due to the nature of soft bodies.To obtain a holistic view of the system’s behavior determining the governing dynamics is deemed necessary.This paper proposes a new technique to simulate the dynamic lateral undulation of a soft robotic fish with a cable-driven soft tail.By integrating the rigid finite element method with rigid-body robotics,the model represents the undulation of a finite number of rigid elements connected through a set of torsional spring and damper.Instead of directly modeling external forces,we substitute equivalent joint torques into the system dynamics,allowing us to consider external effects without complicating the model.The resulting model yields valuable insights into the system’s behavior,including propulsive and lateral forces.A comparison with experimental results shows strong agreement,with a tip amplitude error of 10% at 0.8 Hz,5.25% at 1.6 Hz and 2.54%at 2.2 Hz flapping frequency.These findings illuminate the influence of lateral undulation on the overall dynamics,paving the way for fully autonomous robotic fish.
基金Supported by National Nature Science Foundation of China(Grant Nos.52205225,U2330202)The Foundation Project of China(Grant No.2023-JCJQ-JJ-0958).
文摘With the intensification of lunar exploration,the failure risk caused by the adsorption of lunar dust on the spacecraft surface cannot be ignored.Therefore,three types of typical spatial solid lubrication films,namely polytetrafluoroethylene(PTFE),amorphous carbon(a-C)and molybdenum disulfide(MoS2),were prepared as test samples.Firstly,the surface free energy parameters of the material were measured using a contact Angle measuring instrument.At the same time,atomic force microscopy(AFM)was used to quantify the adhesion of the film samples based on the lunar dust micro-adsorption model.In order to investigate the influence of the test environment,the environmental pressure was adjusted to normal pressure environment and high vacuum environment with a vacuum degree of 10−6 Pa for testing.The results indicate a positive correlation between surface energy and adhesion.As surface energy increases,molecules tend to move closer,forming a stronger attraction and thus enhancing surface adhesion.In addition,AFM was used to measure the adhesion force under atmospheric pressure and vacuum conditions,revealing that parameters measured in atmospheric environment were generally higher than those measured in vacuum,which effectively verified the existence of capillary force in the microscopic adsorption model and its influence on the adhesion effect.Through the test comparison of three groups of typical solid lubricating films,it is found that MoS2 has a lower adhesion effect than the other two groups of films,which can effectively reduce the adhesion phenomenon of lunar dust on the surface of the material,and provide suitable materials for future lunar exploration and manned lunar missions.
基金support by Hong Kong RGC General Research Fund(16217824,16213825,16203923,and 16217824)National Natural Science Foundation of China(N_HKUST638/23)+1 种基金Research Grants Council Joint Research Scheme(62361166630)Guangdong Basic and Applied Basic Research Foundation(2023B1515130007).
文摘Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile sensors,accurately decoupling signals—specifically separating forces from directional orientation and temperature—remains a challenge thus resulting in failure to meet the advanced application requirements of robots.This study proposes,F3T,a multilayer soft sensor unit designed to achieve isolated measurements and mathematical decoupling of normal pressure,omnidirectional tangential forces,and temperature.We developed a circular coaxial magnetic film featuring a floating mount multilayer capacitor that facilitated the physical decoupling of normal and tangential forces in all directions.Additionally,we incorporated an ion gel-based temperature-sensing film into the tactile sensor.The proposed sensor was resilient to external pressures and deformations,and could measure temperature and significantly eliminate capacitor errors induced by environmental temperature changes.In conclusion,our novel design allowed for the decoupled measurement of multiple signals,laying the foundation for advancements in high-level robotic motion control,autonomous decision-making,and task planning.
