Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant products.However,few research on solvent transport dynamics...Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant products.However,few research on solvent transport dynamics within NC-based propellants was reported,and its effect on the evolution of mechanical properties was not interpreted yet.This study is conducted to gain a comprehensive understanding of hot-air drying for NC-based propellants and clarify the effect of temperature on solvent transport behavior and further the change of mechanical properties during drying.The drying kinetic curves show the drying time required is decreased but the steady solvent content is increased and the drying rate is obviously increased with the increase of hot-air temperatures,indicating hot-air temperatures have a significant effect on drying kinetics.A modified drying model was established,and results show it is more appropriate to describe solvent transport behavior within NC-based propellants.Moreover,two linear equations were established to exhibit the relationship between solvent content and its effect on the change of tensile properties,and the decrease of residual solvent content causes an obvious increase of tensile strength and tensile modulus of propellant products,indicating its mechanical properties can be partly improved by adjustment of residual solvent content.The outcomes can be used to clarify solvent transport mechanisms and optimize drying process parameters of double-based gun propellants.展开更多
In the lattice system,when the synthetic flux reaches aπphase along a closed loop under the synthetic gauge field,destructive interference occurs and gives rise to the localization phenomenon.This is known as the Aha...In the lattice system,when the synthetic flux reaches aπphase along a closed loop under the synthetic gauge field,destructive interference occurs and gives rise to the localization phenomenon.This is known as the Aharonov-Bohm(AB)caging effect.It provides a powerful tool for the study of quantum transport and dynamical effects.In the system where lattice sites possess internal structure and the underlying gauge field is non-Abelian,localization can also occur,forming the non-Abelian AB caging.Here,we propose an experimental scheme to synthesize non-Abelian gauge fields with a single trapped ion by coupling multiple internal levels and Fock states in its motion via laser fields.In contrast to the Abelian AB caging,we numerically observe that the non-Abelian AB caging occurs either when the interference matrix is nilpotent,or when the initial state is specifically set.Our experimental scheme broadens the study of localization phenomena and provides a novel tool for the study of non-Abelian physics.展开更多
The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and ...The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.展开更多
The heat conduction and thermal conductivity for methane hydrate are simulated from equilibrium molecular dynamics. The thermal conductivity and temperature dependence trend agree well with the experimental results. T...The heat conduction and thermal conductivity for methane hydrate are simulated from equilibrium molecular dynamics. The thermal conductivity and temperature dependence trend agree well with the experimental results. The nonmonotonic temperature dependence is attributed to the phonon inelastic scattering at higher temperature and to the confinement of the optic phonon modes and low frequency phonons at low temperature. The thermal conductivity scales proportionally with the van der Waals interaction strength, The conversion of a crystal-like nature into an amorphous one oecurs at higher strength. Both the temperature dependence and interaction strength dependence are explained by phonon inelastic scattering.展开更多
This study explores the transport dynamics of temporary plugging balls in multi-cluster horizontal wellbores through a three-dimensional Computational Fluid Dynamics(CFD)model based on field dimensions.An experimental...This study explores the transport dynamics of temporary plugging balls in multi-cluster horizontal wellbores through a three-dimensional Computational Fluid Dynamics(CFD)model based on field dimensions.An experimental setup mimicking the transport of these balls was utilized to validate the model,revealing a maximum discrepancy of less than 22.2% in ball allocation proportions under identical conditions.This validation substantiates the model's precision in predicting transport dynamics across various operational scenarios.Key parameters,including pump rate,fluid viscosity,perforation discharge capacity,ball diameter,ball density,and the number of balls,were examined using the validated model.Findings indicate that pump rate,ball density,and perforation discharge capacity markedly influence ball distribution,followed by fluid viscosity.The number of balls has a lesser effect.Elevated pump rates augment inertial forces,prompting balls to migrate towards the toe-side of the wellbore.Moderate fluid viscosities enhance distribution uniformity,whereas extreme viscosities do not.Perforation clusters with higher discharge capacities attract more balls,thereby improving plugging efficiency.Lower ball density and smaller diameter yield more uniform distribution,while higher values lead to ball accumulation at the toe-end.This study offers valuable insights for optimizing parameters in temporary plugging fracturing technology,thereby improving the efficiency and effectiveness of hydraulic fracturing treatments.展开更多
With the 3D chemical transport model OSLO CTM2, the valley of total column ozone over the Tibetan Plateau in summer is reproduced. The results show that when the ozone valley occurs and develops, the transport process...With the 3D chemical transport model OSLO CTM2, the valley of total column ozone over the Tibetan Plateau in summer is reproduced. The results show that when the ozone valley occurs and develops, the transport process plays the main part in the ozone reduction, but the chemical process partly compensates for the transport process. In the dynamic transport process of ozone, the horizontal transport process plays the main part in the ozone reduction in May, but brings about the ozone increase in June and July. The vertical advective process gradually takes the main role in the ozone reduction in June and July. The effect of convective activities rises gradually so that this effect cannot be overlooked in July, as its magnitude is comparable to that of the net changes. The effect of the gaseous chemical process brings about ozone increases which are more than the net changes sometimes, so the chemical effect is also important.展开更多
Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method （LBM） and random walk （RW）, respectively. The numerical implementation isdeveloped and validat...Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method （LBM） and random walk （RW）, respectively. The numerical implementation isdeveloped and validated on general purpose graphic processing units （GPGPUs）. Both the LBM and RWmethod are well suited to parallel implementation on GPGPUs because they require only next-neighbourcommunication and thus can reduce expenses. The LBM model is an order of magnitude faster onGPGPUs than published results for LBM simulations run on modern CPUs. The fluid model is verified forparallel plate flow, backward facing step and single fracture flow; and the RWmodel is verified for pointsourcediffusion, Taylor-Aris dispersion and breakthrough behaviour in a single fracture. Both algorithmsplace limitations on the discrete displacement of fluid or particle transport per time step to minimise thenumerical error that must be considered during implementation. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
Having criticized the current architecture of Advanced Traveler Information Systems （ATISs）, this work discusses a new base of requirements to develop a new paradigm for traffic information systems. It mainly integr...Having criticized the current architecture of Advanced Traveler Information Systems （ATISs）, this work discusses a new base of requirements to develop a new paradigm for traffic information systems. It mainly integrates three dimensions within a traffic system： drivers＇ pattern of behavior and preferences, urban traffic desires, and capabilities of traffic information service providers. Based on the above, functional segments from several related backgrounds are brought together to structure a new architecture, called Interactive Traveler Information System （ITIS）. The main interactive feature of this new architecture is a two-way communication track between drivers and the traffic information system provider-in fact, a decision on choosing a road at a particular time for an individual will be made based on the utility of both sides. This new configuration consists of driver-side smartphone application, centric traffic prediction, and decision-maker units, which will shape a new approach of decision-making processes. These all work together to satisfy the designated goal of ITIS, which is preserving the Wardrop equilibrium condition in the traffic network level. Finally, we concentrate on a comparison study, which shows a differentiation between performance of the proposed ITIS and the current ATIS model in a real situation. This has been done with simulations of analogical scenarios. The most noticeable advantage of the proposed architecture is not being limited to a saturation limit, and the positive effect of increasing system penetration in the performance of the newly introduced information system. In conclusion, new research subjects are suggested to be carried out.展开更多
In order to illustrate the ion transport mechanism of chloride channel（Cl C） protein,a type of Cl C protein,Cl C-ec1,from Escherichia coli is embedded into an explicit membranewater system by using software VMD. The...In order to illustrate the ion transport mechanism of chloride channel（Cl C） protein,a type of Cl C protein,Cl C-ec1,from Escherichia coli is embedded into an explicit membranewater system by using software VMD. Then a parallel molecular dynamics（MD） simulation is employed to equilibrate the Cl C-ec1 structure for 27.5 ns at temperature 298.15 K. Based on this equilibrated structure,we compute the channel geometric size variation and electrostatic potential distribution along the channel. Meanwhile,Cl^- transport process is simulated using oriented random walk method under variable external potential. The simulation result shows that Cl^- transport velocity depends on the width of the narrowest channel region. Mutation of negative glutamate E148 can produce positive potential,which is beneficial for Cl^- transport,around external Cl^- binding region in the channel. The simulated current-voltage curves about Cl^- transporting in Cl C-ec1 protein agree with Jayaram＇s experimental results.展开更多
A Monte Carlo simulation method with an instantaneous density dependent meanfree-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a l...A Monte Carlo simulation method with an instantaneous density dependent meanfree-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a low pressure inert gas.The ablated-particle density and velocity distributions are analyzed.The force distributions acting on the ablated particles are investigated.The influence of the substrate on the ablated-particle velocity distribution and the force distribution acting on the ablated particles are discussed.The Monte Carlo simulation results approximately agree with the experimental data at the pressure of 8 Pa to 17 Pa.This is helpful to investigate the gas phase nucleation and growth mechanism of nanoparticles.展开更多
The existing acoustic logging methods for evaluating the hydraulic fracturing effectiveness usually use the fracture density to evaluate the fracture volume, and the results often cannot accurately reflect the actual ...The existing acoustic logging methods for evaluating the hydraulic fracturing effectiveness usually use the fracture density to evaluate the fracture volume, and the results often cannot accurately reflect the actual productivity. This paper studies the dynamic fluid flow through hydraulic fractures and its effect on borehole acoustic waves. Firstly, based on the fractal characteristics of fractures observed in hydraulic fracturing experiments, a permeability model of complex fracture network is established. Combining the dynamic fluid flow response of the model with the Biot-Rosenbaum theory that describes the acoustic wave propagation in permeable formations, the influence of hydraulic fractures on the velocity dispersion of borehole Stoneley-wave is then calculated and analyzed, whereby a novel hydraulic fracture fluid transport property evaluation method is proposed. The results show that the Stoneley-wave velocity dispersion characteristics caused by complex fractures can be equivalent to those of the plane fracture model, provided that the average permeability of the complex fracture model is equal to the permeability of the plane fracture. In addition, for fractures under high-permeability(fracture width 10~100 μm, permeability ~100 μm^(2)) and reduced permeability(1~10 μm, ~10 μm^(2), as in fracture closure) conditions, the Stoneley-wave velocity dispersion characteristics are significantly different. The field application shows that this fluid transport property evaluation method is practical to assess the permeability and the connectivity of hydraulic fractures.展开更多
For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to exa...For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to examine the predictability of CFD model for the headbox in industrial scale,two pulp suspensions before mixing were treated as homogeneous flows separately.Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations.A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure–velocity coupling.Results show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube,and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.展开更多
The aim of this paper is to investigate the effect of vehicle dynamics control systems （VDCS） on both the collision of the vehicle body and the kinematic behaviour of the ve- hicle＇s occupant in case of offset fron...The aim of this paper is to investigate the effect of vehicle dynamics control systems （VDCS） on both the collision of the vehicle body and the kinematic behaviour of the ve- hicle＇s occupant in case of offset frontal vehicle-to-vehicle collision. A unique 6-degree-of- freedom （6-DOF） vehicle dynamics/crash mathematical model and a simplified lumped mass occupant model are developed. The first model is used to define the vehicle body crash parameters and it integrates a vehicle dynamics model with a vehicle front-end structure model. The second model aims to predict the effect of VDCS on the kinematics of the occupant. It is shown from the numerical simulations that the vehicle dynamics/crash response and occupant behaviour can be captured and analysed quickly and accurately. Yurthermore, it is shown that the VDCS can affect the crash characteristics positively and the occupant behaviour is improved.展开更多
Iontronics based on nanoconfined effects exhibit enhanced ion dynamics and have become more important in the fields such as energy harvesting and storage,sensors,and human-machine communications,which maybe an alterna...Iontronics based on nanoconfined effects exhibit enhanced ion dynamics and have become more important in the fields such as energy harvesting and storage,sensors,and human-machine communications,which maybe an alternative or supplementary solution to electronics due to their biocompatibility and safety.The enhanced ion dynamics can be attributable to the strong interactions between ions and the electrical double layer(EDL)in the nanoconfined spaces.Therefore,in this review,an overview of the EDL is firstly provided,with its distinctive nanoconfined effects in governing ion dynamics highlighted.The primary material frameworks associated with nanoconfined spaces,including nanopores,nanochannels,and multidimensional nanostructures,are systematically classified.Strategies for modulating ion dynamics through external physical and chemical fields are explored,forming the basis for iontronic applications driven by nanoconfined effects.These applications are presented,encompassing iontronic power sources,sensors,logic components such as memristors,diodes,and transistors,as well as iontronic filter capacitors,with their unparalleled advantages in biosafety,flexibility,cost-effectiveness,and environmental adaptability emphasized.Finally,existing challenges in nanoconfined iontronics are addressed,with the expectation that advancements in nanoconfined iontronics will catalyze more efficient energy and information flow.展开更多
Aerospace dielectric components on spacecrafts are frequently exposed to surface charging.Here the dynamic charging behaviours of advanced aerospace dielectrics under electron beam irradiation are investigated.Combine...Aerospace dielectric components on spacecrafts are frequently exposed to surface charging.Here the dynamic charging behaviours of advanced aerospace dielectrics under electron beam irradiation are investigated.Combined measurement of dielectric secondary emission yield(SEY)and trap distribution provides input parameters of a driftdiffusion transport model reproducing the beam-irradiated dielectric charging processes.The model reveals the spatial-temporal evolutions of the current,charge density,and electric field distribution.The model-predicted sample current,SEY and surface potential,in a surface layer of 1μm and with incident electron energy range of 10-30 keV,are compared with the experiments,showing qualitative agreement.The effects of beam energy and current,dielectric material,and sample thickness on the charging processes are explored.Relation between the beam energy and final surface potential is determined,and the beam current is found to only affect the charging speed.Dielectric parameters including the mass density,permittivity,surface resistivity,trap state distribution,electron affinity,together influence the charging speed and final charged state.展开更多
To improve the resilience of distribution networks(DNs),a multi-stage dynamic recovery strategy is proposed in this paper,which is designed for post-disaster DN considering an integrated energy system(IES)and transpor...To improve the resilience of distribution networks(DNs),a multi-stage dynamic recovery strategy is proposed in this paper,which is designed for post-disaster DN considering an integrated energy system(IES)and transportation network(TN).First,the emergency response quickly increases the output of gas turbines(GTs)in the natural gas network(NGN),and responsively reconfigures the DN in microgrids,to maximize the amount of loads to be restored.The single-commodity flow model is adopted to construct spanning tree constraints.Then,in the second stage of energy storage recovery,mobile energy storage systems(MESSs)are deployed to cover the shortages of power demands,i.e.,to further restore the loads after evaluating the load recovery situation.The Floyd algorithm based dynamic traffic assignment(DTA)is selected to obtain the optimal path of the MESSs.In the third stage,the outputs of various post-disaster recovery measures are adjusted to achieve an economically optimized operation.Case studies demonstrate the effectiveness of the proposed dynamic post-disaster recovery strategy.展开更多
The container sea-rail multimodal transport system faces complex challenges with de- mand uncertainties for joint slot allocation and dynamic pricing. The challenge is formulated as a two-stage optimal model based on ...The container sea-rail multimodal transport system faces complex challenges with de- mand uncertainties for joint slot allocation and dynamic pricing. The challenge is formulated as a two-stage optimal model based on revenue management （RM） as actual slots sale of multi-node container sea-rail multimodal transport usually includes contract sale to large shippers and free sale to scattered shippers. First stage in the model utilizes an origin-destination control approach, formulated as a stochastic integer programming equation, to settle long-term slot allocation in the contract market and empty container allocation. Second stage in the model is formulated as a stochastic nonlinear programming equation to solve a multiproduct joint dynamic pricing and inventory control problem for price settling and slot allocation in each period of free market. Considering the random nature of demand, the methods of chance constrained programming and robust optimi- zation are utilized to transform stochastic models into deterministic models. A numerical experiment is presented to verify the availability of models and solving methods. Results of considering uncertain/certain demand are compared, which show that the two-stage optimal strategy integrating slot allocation with dynamic pricing considering random de- mand is revealed to increase the revenue for multimodal transport operators （MTO） while concurrently satisfying shippers＇ demand. Research resulting from this paper will contribute to the theory and practice of container sea-rail multimodal transport revenue management and provide a scientific decision-making tool for MTO.展开更多
We consider the stabilisation of discrete-time nonlinear systems that are actuated through a pair of transport partial difference equation(PdE)systems that convect in the opposite directions from one another.An explic...We consider the stabilisation of discrete-time nonlinear systems that are actuated through a pair of transport partial difference equation(PdE)systems that convect in the opposite directions from one another.An explicit feedback law that compensates the discrete PdE dynamics is designed.Global asymptotic stability of the closedloop system is proved with the aid of a Lyapunov function.The feedback design is illustrated through an example.The proposed design in this paper allows the delay to be arbitrarily long and time-varying.Furthermore,our predictor feedback law in discrete time is explicit as the predictor state is computed by an algebraic equation.展开更多
Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries globally.Lingdingyang Estuary(L...Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries globally.Lingdingyang Estuary(LE),located in the central and southern part of the Pearl River Delta,southern China with a long history of high-intensity anthropogenic disturbances,was studied to explore the contribution rate and mechanism underlying the alteration in hydrodynamics and sediment transport under each phase of human activity.A state-of-the-art modeling tool(TELEMAC-2D),was used to study the variations in the hydrodynamics and sediment transport,accounting for reclamation-induced shoreline and dredging-induced topography changes.The results indicated that:i)under the influence of successive land reclamation,the general distribution of the Confluence Hydrodynamic Zone(CHZ)in LE varied from scattered to concentrated,and these zones moved 3–5 km seaward.ii)Large-scale channel dredging weakened the residual flow in LE,decreasing the residual flow in the Inner-Lingding Estuary(ILE)by 62.45%.This was initiated by the enhancement of tidal dynamics through changes in the bottom friction caused by dredging in the ILE.In contrast,massive reclamation decreased the residual flow in the ILE by 17.55%and increased that in the Outer-Lingding Estuary(OLE).iii)Despite disturbances related to land reclamation and dredging,the estuarine jet flow in LE remained a turbulent jet system,and the estuarine jet flow became more asymmetrical.In addition,the position of the estuarine jet source moved 6–13 km seaward.iv)Both reclamation and dredging decreased the SSC in the ILE and increased the SSC in the OLE.Reclamation weakened the SSC in the ILE by 62.19%,whereas dredging enhanced the SSC in the OLE by 49%.Spatially,reclamation resulted in an increase in the SSC near the outlets and a decrease in the SSC in the northern portion of the Western Channel.Dredging mainly increased the SSC in the northern part of the OLE.v)The increase in the barotropic pressure gradient was the main factor driving the enhancement of the residual flow and SSC near the outlets.Moreover,the southward location of the“artificial outlets”favored the transport of suspended sediments to the OLE,which was one of the primary reasons for the increase in the SSC in the OLE.Finally,the tidal dynamics of the ILE intensified due to massive reclamation and dredging.The findings of this study indicate that hydrodynamics and sediment transport in LE have greatly changed over the last decades,with reclamation and dredging being the crucial drivers.The insights obtained from this study can serve as a reference for the comprehensive management of the Pearl River Estuary and other large estuaries experiencing similar anthropogenic forcing.展开更多
Synaptic vesicle transport by motor proteins along microtubules is a crucially active process underlying neuronal communication.It is known that microtubules are destabilized by tau-hyperphosphorylation,which causes t...Synaptic vesicle transport by motor proteins along microtubules is a crucially active process underlying neuronal communication.It is known that microtubules are destabilized by tau-hyperphosphorylation,which causes tau proteins to detach from microtubules and form neurofibril tangles.However,how tauphosphorylation affects the transport dynamics of motor proteins on the microtubule remains unknown.Here,we discover that the long-distance unidirectional motion of vesicle-motor protein multiplexes(VMPMs)in living cells is suppressed under tauhyperphosphorylation,with the consequent loss of fast vesicletransport along the microtubule.The VMPMs in hyperphosphorylated cells exhibit seemingly bidirectional random motion,with dynamic properties far different from those of VMPM motion in normal cells.We establish a parsimonious physicochemical model of VMPM’s active motion that provides a unified,quantitative explanation and predictions for our experimental results.Our analysis reveals that,under hyperphosphorylation conditions,motor protein multiplexes have both static and dynamic motility fluctuations.The loss of fast vesicle-transport along the microtubule can be a mechanism of neurodegenerative disorders associated with tau-hyperphosphorylation.展开更多
基金the National Natural Science Foundation of China(Grant No.22075146).
文摘Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant products.However,few research on solvent transport dynamics within NC-based propellants was reported,and its effect on the evolution of mechanical properties was not interpreted yet.This study is conducted to gain a comprehensive understanding of hot-air drying for NC-based propellants and clarify the effect of temperature on solvent transport behavior and further the change of mechanical properties during drying.The drying kinetic curves show the drying time required is decreased but the steady solvent content is increased and the drying rate is obviously increased with the increase of hot-air temperatures,indicating hot-air temperatures have a significant effect on drying kinetics.A modified drying model was established,and results show it is more appropriate to describe solvent transport behavior within NC-based propellants.Moreover,two linear equations were established to exhibit the relationship between solvent content and its effect on the change of tensile properties,and the decrease of residual solvent content causes an obvious increase of tensile strength and tensile modulus of propellant products,indicating its mechanical properties can be partly improved by adjustment of residual solvent content.The outcomes can be used to clarify solvent transport mechanisms and optimize drying process parameters of double-based gun propellants.
基金supported by the National Natural Science Foundation of China(Grant Nos.92165206,12275090,and 12304554)the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0301603 and 2021ZD0302303)。
文摘In the lattice system,when the synthetic flux reaches aπphase along a closed loop under the synthetic gauge field,destructive interference occurs and gives rise to the localization phenomenon.This is known as the Aharonov-Bohm(AB)caging effect.It provides a powerful tool for the study of quantum transport and dynamical effects.In the system where lattice sites possess internal structure and the underlying gauge field is non-Abelian,localization can also occur,forming the non-Abelian AB caging.Here,we propose an experimental scheme to synthesize non-Abelian gauge fields with a single trapped ion by coupling multiple internal levels and Fock states in its motion via laser fields.In contrast to the Abelian AB caging,we numerically observe that the non-Abelian AB caging occurs either when the interference matrix is nilpotent,or when the initial state is specifically set.Our experimental scheme broadens the study of localization phenomena and provides a novel tool for the study of non-Abelian physics.
基金MGMR Eighth Five- Year Plan Basic Geology Research Foundation Grant 8502216China National Natural Science Foundation Grant 49173169
文摘The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.
基金Supported by the National Natural Science Foundation of China under Grant Nos U1262112 and 51176205
文摘The heat conduction and thermal conductivity for methane hydrate are simulated from equilibrium molecular dynamics. The thermal conductivity and temperature dependence trend agree well with the experimental results. The nonmonotonic temperature dependence is attributed to the phonon inelastic scattering at higher temperature and to the confinement of the optic phonon modes and low frequency phonons at low temperature. The thermal conductivity scales proportionally with the van der Waals interaction strength, The conversion of a crystal-like nature into an amorphous one oecurs at higher strength. Both the temperature dependence and interaction strength dependence are explained by phonon inelastic scattering.
基金supported by the National Natural Science Foundation of China(Nos.52404052,51804268)the Open Project Program of the State Energy Center for Shale Oil Research and Development(No.33550000-22-ZC0613-0376).
文摘This study explores the transport dynamics of temporary plugging balls in multi-cluster horizontal wellbores through a three-dimensional Computational Fluid Dynamics(CFD)model based on field dimensions.An experimental setup mimicking the transport of these balls was utilized to validate the model,revealing a maximum discrepancy of less than 22.2% in ball allocation proportions under identical conditions.This validation substantiates the model's precision in predicting transport dynamics across various operational scenarios.Key parameters,including pump rate,fluid viscosity,perforation discharge capacity,ball diameter,ball density,and the number of balls,were examined using the validated model.Findings indicate that pump rate,ball density,and perforation discharge capacity markedly influence ball distribution,followed by fluid viscosity.The number of balls has a lesser effect.Elevated pump rates augment inertial forces,prompting balls to migrate towards the toe-side of the wellbore.Moderate fluid viscosities enhance distribution uniformity,whereas extreme viscosities do not.Perforation clusters with higher discharge capacities attract more balls,thereby improving plugging efficiency.Lower ball density and smaller diameter yield more uniform distribution,while higher values lead to ball accumulation at the toe-end.This study offers valuable insights for optimizing parameters in temporary plugging fracturing technology,thereby improving the efficiency and effectiveness of hydraulic fracturing treatments.
文摘With the 3D chemical transport model OSLO CTM2, the valley of total column ozone over the Tibetan Plateau in summer is reproduced. The results show that when the ozone valley occurs and develops, the transport process plays the main part in the ozone reduction, but the chemical process partly compensates for the transport process. In the dynamic transport process of ozone, the horizontal transport process plays the main part in the ozone reduction in May, but brings about the ozone increase in June and July. The vertical advective process gradually takes the main role in the ozone reduction in June and July. The effect of convective activities rises gradually so that this effect cannot be overlooked in July, as its magnitude is comparable to that of the net changes. The effect of the gaseous chemical process brings about ozone increases which are more than the net changes sometimes, so the chemical effect is also important.
文摘Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method （LBM） and random walk （RW）, respectively. The numerical implementation isdeveloped and validated on general purpose graphic processing units （GPGPUs）. Both the LBM and RWmethod are well suited to parallel implementation on GPGPUs because they require only next-neighbourcommunication and thus can reduce expenses. The LBM model is an order of magnitude faster onGPGPUs than published results for LBM simulations run on modern CPUs. The fluid model is verified forparallel plate flow, backward facing step and single fracture flow; and the RWmodel is verified for pointsourcediffusion, Taylor-Aris dispersion and breakthrough behaviour in a single fracture. Both algorithmsplace limitations on the discrete displacement of fluid or particle transport per time step to minimise thenumerical error that must be considered during implementation. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
文摘Having criticized the current architecture of Advanced Traveler Information Systems （ATISs）, this work discusses a new base of requirements to develop a new paradigm for traffic information systems. It mainly integrates three dimensions within a traffic system： drivers＇ pattern of behavior and preferences, urban traffic desires, and capabilities of traffic information service providers. Based on the above, functional segments from several related backgrounds are brought together to structure a new architecture, called Interactive Traveler Information System （ITIS）. The main interactive feature of this new architecture is a two-way communication track between drivers and the traffic information system provider-in fact, a decision on choosing a road at a particular time for an individual will be made based on the utility of both sides. This new configuration consists of driver-side smartphone application, centric traffic prediction, and decision-maker units, which will shape a new approach of decision-making processes. These all work together to satisfy the designated goal of ITIS, which is preserving the Wardrop equilibrium condition in the traffic network level. Finally, we concentrate on a comparison study, which shows a differentiation between performance of the proposed ITIS and the current ATIS model in a real situation. This has been done with simulations of analogical scenarios. The most noticeable advantage of the proposed architecture is not being limited to a saturation limit, and the positive effect of increasing system penetration in the performance of the newly introduced information system. In conclusion, new research subjects are suggested to be carried out.
基金Supported by the National Natural Science Foundation of China(11304123)the Scientific Research Foundation of Jianghan University(2013016)
文摘In order to illustrate the ion transport mechanism of chloride channel（Cl C） protein,a type of Cl C protein,Cl C-ec1,from Escherichia coli is embedded into an explicit membranewater system by using software VMD. Then a parallel molecular dynamics（MD） simulation is employed to equilibrate the Cl C-ec1 structure for 27.5 ns at temperature 298.15 K. Based on this equilibrated structure,we compute the channel geometric size variation and electrostatic potential distribution along the channel. Meanwhile,Cl^- transport process is simulated using oriented random walk method under variable external potential. The simulation result shows that Cl^- transport velocity depends on the width of the narrowest channel region. Mutation of negative glutamate E148 can produce positive potential,which is beneficial for Cl^- transport,around external Cl^- binding region in the channel. The simulated current-voltage curves about Cl^- transporting in Cl C-ec1 protein agree with Jayaram＇s experimental results.
基金supported by the Natural Science Foundation of Hebei Province,China(No.A2015201166)the Natural Science Foundation of Hebei University,China(No.2013-252)
文摘A Monte Carlo simulation method with an instantaneous density dependent meanfree-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a low pressure inert gas.The ablated-particle density and velocity distributions are analyzed.The force distributions acting on the ablated particles are investigated.The influence of the substrate on the ablated-particle velocity distribution and the force distribution acting on the ablated particles are discussed.The Monte Carlo simulation results approximately agree with the experimental data at the pressure of 8 Pa to 17 Pa.This is helpful to investigate the gas phase nucleation and growth mechanism of nanoparticles.
基金Supported by the National Natural Science Foundation of China (41821002,42174145)PetroChina Science and Technology Major Project (ZD2019-183-004)China University of Petroleum (East China) Graduate Student Innovation Project (YCX2019001)。
文摘The existing acoustic logging methods for evaluating the hydraulic fracturing effectiveness usually use the fracture density to evaluate the fracture volume, and the results often cannot accurately reflect the actual productivity. This paper studies the dynamic fluid flow through hydraulic fractures and its effect on borehole acoustic waves. Firstly, based on the fractal characteristics of fractures observed in hydraulic fracturing experiments, a permeability model of complex fracture network is established. Combining the dynamic fluid flow response of the model with the Biot-Rosenbaum theory that describes the acoustic wave propagation in permeable formations, the influence of hydraulic fractures on the velocity dispersion of borehole Stoneley-wave is then calculated and analyzed, whereby a novel hydraulic fracture fluid transport property evaluation method is proposed. The results show that the Stoneley-wave velocity dispersion characteristics caused by complex fractures can be equivalent to those of the plane fracture model, provided that the average permeability of the complex fracture model is equal to the permeability of the plane fracture. In addition, for fractures under high-permeability(fracture width 10~100 μm, permeability ~100 μm^(2)) and reduced permeability(1~10 μm, ~10 μm^(2), as in fracture closure) conditions, the Stoneley-wave velocity dispersion characteristics are significantly different. The field application shows that this fluid transport property evaluation method is practical to assess the permeability and the connectivity of hydraulic fractures.
基金Supported by the Science&Technology Plan Projects of Guangzhou City(15020079,Study on Quality Intelligent Control of Modern Paper Machine and Energy-saving Technology with Equipment)Guangdong Provincial Science&Technology Plan Projects(2015B020241001,Research and Application of Biomass Pretreatment and Ethanol Production Technology)
文摘For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to examine the predictability of CFD model for the headbox in industrial scale,two pulp suspensions before mixing were treated as homogeneous flows separately.Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations.A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure–velocity coupling.Results show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube,and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.
基金the Egyptian government and the Faculty of Engineering,Ain Shams University for supporting this research
文摘The aim of this paper is to investigate the effect of vehicle dynamics control systems （VDCS） on both the collision of the vehicle body and the kinematic behaviour of the ve- hicle＇s occupant in case of offset frontal vehicle-to-vehicle collision. A unique 6-degree-of- freedom （6-DOF） vehicle dynamics/crash mathematical model and a simplified lumped mass occupant model are developed. The first model is used to define the vehicle body crash parameters and it integrates a vehicle dynamics model with a vehicle front-end structure model. The second model aims to predict the effect of VDCS on the kinematics of the occupant. It is shown from the numerical simulations that the vehicle dynamics/crash response and occupant behaviour can be captured and analysed quickly and accurately. Yurthermore, it is shown that the VDCS can affect the crash characteristics positively and the occupant behaviour is improved.
基金supported by the National Natural Science Foundation of China(No.22479016).
文摘Iontronics based on nanoconfined effects exhibit enhanced ion dynamics and have become more important in the fields such as energy harvesting and storage,sensors,and human-machine communications,which maybe an alternative or supplementary solution to electronics due to their biocompatibility and safety.The enhanced ion dynamics can be attributable to the strong interactions between ions and the electrical double layer(EDL)in the nanoconfined spaces.Therefore,in this review,an overview of the EDL is firstly provided,with its distinctive nanoconfined effects in governing ion dynamics highlighted.The primary material frameworks associated with nanoconfined spaces,including nanopores,nanochannels,and multidimensional nanostructures,are systematically classified.Strategies for modulating ion dynamics through external physical and chemical fields are explored,forming the basis for iontronic applications driven by nanoconfined effects.These applications are presented,encompassing iontronic power sources,sensors,logic components such as memristors,diodes,and transistors,as well as iontronic filter capacitors,with their unparalleled advantages in biosafety,flexibility,cost-effectiveness,and environmental adaptability emphasized.Finally,existing challenges in nanoconfined iontronics are addressed,with the expectation that advancements in nanoconfined iontronics will catalyze more efficient energy and information flow.
基金National Natural Science Foundation of China,Grant/Award Number:12375205Fundamental Research Funds for the Central Universities,Grant/Award Number:xzy012023153Swiss National Science Foundation。
文摘Aerospace dielectric components on spacecrafts are frequently exposed to surface charging.Here the dynamic charging behaviours of advanced aerospace dielectrics under electron beam irradiation are investigated.Combined measurement of dielectric secondary emission yield(SEY)and trap distribution provides input parameters of a driftdiffusion transport model reproducing the beam-irradiated dielectric charging processes.The model reveals the spatial-temporal evolutions of the current,charge density,and electric field distribution.The model-predicted sample current,SEY and surface potential,in a surface layer of 1μm and with incident electron energy range of 10-30 keV,are compared with the experiments,showing qualitative agreement.The effects of beam energy and current,dielectric material,and sample thickness on the charging processes are explored.Relation between the beam energy and final surface potential is determined,and the beam current is found to only affect the charging speed.Dielectric parameters including the mass density,permittivity,surface resistivity,trap state distribution,electron affinity,together influence the charging speed and final charged state.
基金supported by the Science and Technology Project of the State Grid Corporation of China“Research on resilience technology and application foundation of intelligent distribution network based on integrated energy system”(No.52060019001H).
文摘To improve the resilience of distribution networks(DNs),a multi-stage dynamic recovery strategy is proposed in this paper,which is designed for post-disaster DN considering an integrated energy system(IES)and transportation network(TN).First,the emergency response quickly increases the output of gas turbines(GTs)in the natural gas network(NGN),and responsively reconfigures the DN in microgrids,to maximize the amount of loads to be restored.The single-commodity flow model is adopted to construct spanning tree constraints.Then,in the second stage of energy storage recovery,mobile energy storage systems(MESSs)are deployed to cover the shortages of power demands,i.e.,to further restore the loads after evaluating the load recovery situation.The Floyd algorithm based dynamic traffic assignment(DTA)is selected to obtain the optimal path of the MESSs.In the third stage,the outputs of various post-disaster recovery measures are adjusted to achieve an economically optimized operation.Case studies demonstrate the effectiveness of the proposed dynamic post-disaster recovery strategy.
基金supported by the National Natural Science Foundation of China(No.71372088)the scientific research fund of Education Department of Liaoning Province (No.L2014179,L2013207)
文摘The container sea-rail multimodal transport system faces complex challenges with de- mand uncertainties for joint slot allocation and dynamic pricing. The challenge is formulated as a two-stage optimal model based on revenue management （RM） as actual slots sale of multi-node container sea-rail multimodal transport usually includes contract sale to large shippers and free sale to scattered shippers. First stage in the model utilizes an origin-destination control approach, formulated as a stochastic integer programming equation, to settle long-term slot allocation in the contract market and empty container allocation. Second stage in the model is formulated as a stochastic nonlinear programming equation to solve a multiproduct joint dynamic pricing and inventory control problem for price settling and slot allocation in each period of free market. Considering the random nature of demand, the methods of chance constrained programming and robust optimi- zation are utilized to transform stochastic models into deterministic models. A numerical experiment is presented to verify the availability of models and solving methods. Results of considering uncertain/certain demand are compared, which show that the two-stage optimal strategy integrating slot allocation with dynamic pricing considering random de- mand is revealed to increase the revenue for multimodal transport operators （MTO） while concurrently satisfying shippers＇ demand. Research resulting from this paper will contribute to the theory and practice of container sea-rail multimodal transport revenue management and provide a scientific decision-making tool for MTO.
基金This work is supported by the National Natural Science Foundation of China[grant numbers 61074011 and 61374077].
文摘We consider the stabilisation of discrete-time nonlinear systems that are actuated through a pair of transport partial difference equation(PdE)systems that convect in the opposite directions from one another.An explicit feedback law that compensates the discrete PdE dynamics is designed.Global asymptotic stability of the closedloop system is proved with the aid of a Lyapunov function.The feedback design is illustrated through an example.The proposed design in this paper allows the delay to be arbitrarily long and time-varying.Furthermore,our predictor feedback law in discrete time is explicit as the predictor state is computed by an algebraic equation.
基金funded by the National Natural Science Foundation of China(Grant Nos.42201104,41376101,and 42071123)China Postdoctoral Research Foundation(Grant No.2023M730758)Guangdong Provincial Special Key Project of Six Marine Industries in 2022“Research on Three-dimensional Efficient Utilization of Marine Spatial Resources in Guangdong-Hong Kong-Macao Greater Bay Area”([2022]49).
文摘Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries globally.Lingdingyang Estuary(LE),located in the central and southern part of the Pearl River Delta,southern China with a long history of high-intensity anthropogenic disturbances,was studied to explore the contribution rate and mechanism underlying the alteration in hydrodynamics and sediment transport under each phase of human activity.A state-of-the-art modeling tool(TELEMAC-2D),was used to study the variations in the hydrodynamics and sediment transport,accounting for reclamation-induced shoreline and dredging-induced topography changes.The results indicated that:i)under the influence of successive land reclamation,the general distribution of the Confluence Hydrodynamic Zone(CHZ)in LE varied from scattered to concentrated,and these zones moved 3–5 km seaward.ii)Large-scale channel dredging weakened the residual flow in LE,decreasing the residual flow in the Inner-Lingding Estuary(ILE)by 62.45%.This was initiated by the enhancement of tidal dynamics through changes in the bottom friction caused by dredging in the ILE.In contrast,massive reclamation decreased the residual flow in the ILE by 17.55%and increased that in the Outer-Lingding Estuary(OLE).iii)Despite disturbances related to land reclamation and dredging,the estuarine jet flow in LE remained a turbulent jet system,and the estuarine jet flow became more asymmetrical.In addition,the position of the estuarine jet source moved 6–13 km seaward.iv)Both reclamation and dredging decreased the SSC in the ILE and increased the SSC in the OLE.Reclamation weakened the SSC in the ILE by 62.19%,whereas dredging enhanced the SSC in the OLE by 49%.Spatially,reclamation resulted in an increase in the SSC near the outlets and a decrease in the SSC in the northern portion of the Western Channel.Dredging mainly increased the SSC in the northern part of the OLE.v)The increase in the barotropic pressure gradient was the main factor driving the enhancement of the residual flow and SSC near the outlets.Moreover,the southward location of the“artificial outlets”favored the transport of suspended sediments to the OLE,which was one of the primary reasons for the increase in the SSC in the OLE.Finally,the tidal dynamics of the ILE intensified due to massive reclamation and dredging.The findings of this study indicate that hydrodynamics and sediment transport in LE have greatly changed over the last decades,with reclamation and dredging being the crucial drivers.The insights obtained from this study can serve as a reference for the comprehensive management of the Pearl River Estuary and other large estuaries experiencing similar anthropogenic forcing.
基金supported by the grant awarded from GIST in 2020 through the Research Institute(GRI)program and by the National Research Foundation(NRF)of S.Korea(Grant no.2020R1F1A1073442,2021R1A2C2010557)J.S.was supported by the Creative Research Initiative Project Program(NRF-2015R1A3A2066497)+3 种基金the Engineering Research Center Program funded by the Korea government(MSIT)(NRF-2020R1A5A1018052)Y.H.S.,J.-H.K.,and M.H.L.were supported by the NRF[NRF-2019R1I1A1A01056975(Y.H.S.)NRF-2020R1A2C1102788(J.-H.K.)NRF-2022R1A3B1077319(M.H.L.)]。
文摘Synaptic vesicle transport by motor proteins along microtubules is a crucially active process underlying neuronal communication.It is known that microtubules are destabilized by tau-hyperphosphorylation,which causes tau proteins to detach from microtubules and form neurofibril tangles.However,how tauphosphorylation affects the transport dynamics of motor proteins on the microtubule remains unknown.Here,we discover that the long-distance unidirectional motion of vesicle-motor protein multiplexes(VMPMs)in living cells is suppressed under tauhyperphosphorylation,with the consequent loss of fast vesicletransport along the microtubule.The VMPMs in hyperphosphorylated cells exhibit seemingly bidirectional random motion,with dynamic properties far different from those of VMPM motion in normal cells.We establish a parsimonious physicochemical model of VMPM’s active motion that provides a unified,quantitative explanation and predictions for our experimental results.Our analysis reveals that,under hyperphosphorylation conditions,motor protein multiplexes have both static and dynamic motility fluctuations.The loss of fast vesicle-transport along the microtubule can be a mechanism of neurodegenerative disorders associated with tau-hyperphosphorylation.
