This paper investigates the impact of the model top and damping layer on the numerical simulation of tropical cyclones(TCs)and reveals the significant role of stratospheric gravity waves(SGWs).TCs can generate SGWs,wh...This paper investigates the impact of the model top and damping layer on the numerical simulation of tropical cyclones(TCs)and reveals the significant role of stratospheric gravity waves(SGWs).TCs can generate SGWs,which propagate upward and outward into the stratosphere.These SGWs can reach the damping layer,which is a consequence of the numerical scheme employed,where they can affect the tangential circulation through the dragging and forcing processes.In models with a higher top boundary,this tangential circulation develops far from the TC and has minimal direct impact on TC intensity.By comparison,in models with a lower top(e.g.,20 km),the damping layer is located just above the top of the TC.The SGW dragging in the damping layer and the consequent tangential force can thus induce ascent outside the eyewall,promote latent heat release,tilt the eyewall,and enlarge the inner-core radius.This process will reduce inner-core vorticity advection within the boundary layer,and eventually inhibits the intensification of the TC.This suggests that when the thickness of the damping layer is 5 km,the TC numerical model top height should be at least higher than 20 km to generate more accurate simulations.展开更多
In addition to being driven by tidal winds,the sporadic E(Es)layers are modulated by gravity waves(GWs),although the effects are not yet comprehensively understood.In this article,we discuss the effects of mesoscale G...In addition to being driven by tidal winds,the sporadic E(Es)layers are modulated by gravity waves(GWs),although the effects are not yet comprehensively understood.In this article,we discuss the effects of mesoscale GWs on the Es layers determined by using a newly developed model,MISE-1D(one-dimensional Model of Ionospheric Sporadic E),with low numerical dissipation and high resolution.Driven by the wind fields resolved by the high-resolution version of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension(WACCM-X),the MISE-1D simulation revealed that GWs significantly influence the evolution of the Es layer above 100 km but have a very limited effect at lower altitudes.The effects of GWs are diverse and complex,generally including the generation of fluctuating wavelike structures on the Es layer with frequencies similar to those of the GWs.The mesoscale GWs can also cause increases in the density of Es layers,or they can disperse or diffuse the Es layers and increase their thickness.In addition,the presence of GWs is a key factor in sustaining the Es layers in some cases.展开更多
Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological storage.Based on the Navier-Stokes equation,component mass conservation equation,and fluid proper...Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological storage.Based on the Navier-Stokes equation,component mass conservation equation,and fluid property-composition relationship,a mathematical model for pore-scale CO_(2) injection in oilsaturated porous media was developed in this study.The model can reflect the effects of gravity assistance,component diffusion,fluid density variation,and velocity change on EOR and CO_(2) storage.For nonhomogeneous porous media,the gravity influence and large density difference help to minimize the velocity difference between the main flow path and the surrounding area,thus improving the oil recovery and CO_(2) storage.Large CO_(2) injection angles and oil-CO_(2) density differences can increase the oil recovery by 22.6% and 4.2%,respectively,and increase CO_(2) storage by 37.9% and 4.7%,respectively.Component diffusion facilitates the transportation of the oil components from the low-velocity region to the main flow path,thereby reducing the oil/CO_(2) concentration difference within the porous media.Component diffusion can increase oil recovery and CO_(2) storage by 5.7% and 6.9%,respectively.In addition,combined with the component diffusion,a low CO_(2) injection rate creates a more uniform spatial distribution of the oil/CO_(2) component,resulting in increases of 9.5% oil recovery and 15.7% CO_(2) storage,respectively.This study provides theoretical support for improving the geological CO_(2) storage and EOR processes.展开更多
This paper aims at investigation of the dynamic properties of gravity cage exposed to waves by use of a numerical model. The numerical model is developed, based on lumped mass method to set up the equations of motion ...This paper aims at investigation of the dynamic properties of gravity cage exposed to waves by use of a numerical model. The numerical model is developed, based on lumped mass method to set up the equations of motion of the whole cage; meanwhile the solutions of equations are solved by the Runge-Kutta-Vemer fifth-order and sixth-order method. Physical model tests have been carried out to examine the validity of the numerical model. The results by the numerical simulation agree well with the experimental data.展开更多
Lunar in-situ resource utilization(ISRU)has been put on the agenda by many countries.Due to the special material nature and low gravity environment,the lunar regolith demonstrates significantly different behavior from...Lunar in-situ resource utilization(ISRU)has been put on the agenda by many countries.Due to the special material nature and low gravity environment,the lunar regolith demonstrates significantly different behavior from terrestrial geomaterials.However,the systematic understanding of its geotechnical behavior is now seriously restricted by the scarcity of lunar regolith and the difficulty in simulating lunar gravity.A new lunar regolith simulant,termed as China University of Mining and Technology Number One(CUMT-1),has been developed to recover properties of the lunar regolith and simulate the lunar gravity by adopting the recently advanced geotechnical magnetic-similitude-gravity model testing(GMMT)method.The CUMT-1 simulant was prepared by reproducing the in-situ formation and fragmentation of the lunar matrix,which plays a key role in the irregular particle morphology.The mineralogical compositions,particle morphology and gradation,specific gravity,bulk density,void ratio,shear strength,and compressibility were determined.After quantifying the magnetization and magnetic-similitude-gravity characteristics,an application of the cone penetration resistance under low gravity was further given.The obtained results are compared to the values known for lunar regolith samples and other simulants,which demonstrates promising characteristics for use in geotechnical engineering-based and scientificbased applications,especially considering the influence of lunar gravity.展开更多
Surface co-seismic gravity changes and displacements caused by the Wenchuan Ms8.0 earthquake are calculated on the basis of the half-space dislocation theory and two fault models inversed, respectively, by Institute o...Surface co-seismic gravity changes and displacements caused by the Wenchuan Ms8.0 earthquake are calculated on the basis of the half-space dislocation theory and two fault models inversed, respectively, by Institute of Geophysics, CEA and USGS. The results show that 1 ） the dislocation consists of dip slip and rightlateral strike slip ;2 ）the co-seismic gravity change shows a four-quadrant pattern ,which is greatly controlled by the distribution of the vertical displacements, especially in the near-filed ; 3 ） the gravity change is generally less than 10 × 10^-8 ms^-2 in the far-field,but as high as several 100 × 10^-8 ms^-2 in the near-filed. These results basically agree with observational results.展开更多
Detecting gravity-mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics.We report the result of a simulation of the phenomenon using a photonic platform.The simulation tests t...Detecting gravity-mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics.We report the result of a simulation of the phenomenon using a photonic platform.The simulation tests the idea of probing the quantum nature of a variable by using it to mediate entanglement and yields theoretical and experimental insights,clarifying the operational tools needed for future gravitational experiments.We employ three methods to test the presence of entanglement:the Bell test,entanglement witness,and quantum state tomography.We also simulate the alternative scenario predicted by gravitational collapse models or due to imperfections in the experimental setup and use quantum state tomography to certify the absence of entanglement.The simulation reinforces two main lessons:(1)which path information must be first encoded and subsequently coherently erased from the gravitational field and(2)performing a Bell test leads to stronger conclusions,certifying the existence of gravity-mediated nonlocality.展开更多
By the Volume of Fluid (VOF) multiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for hi...By the Volume of Fluid (VOF) multiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for high Reynolds numbers is demonstrated quantitatively by LES (the Large Eddy Simulation) turbulence model. The gravity currents are simulated for h not equal H as well as h = H, where h is the depth of the gravity current before the release and H is the depth of the intruded fluid. Uprising of swell occurs when a current flows horizontally into another lighter one for h not equal H. The problems under what condition the uprising of swell occurs and how long it takes are considered in this article. All the simulated results are in reasonable agreement with the experimental results available.展开更多
The crustal structure of Xiachayu-Gonghe geophysical profile in eastern Tibetan plateau is simulated with Bouguer anomaly corrected for sediments and lithosphere. The forward simulation shows that the thickness of upp...The crustal structure of Xiachayu-Gonghe geophysical profile in eastern Tibetan plateau is simulated with Bouguer anomaly corrected for sediments and lithosphere. The forward simulation shows that the thickness of upper crust in eastem Tibetan plateau is about 20 km, and the density is 2.78 × 10^3 kg/m^3. The bottom interface of middle crust changes from 30 km to 40 km, the density of middle crust is 2.89 × 10^3 kg/m^3. The materials with low density of 2.78 × 10^3 kg/m^3 exist in middle crust, and those with high density of 3.33 × 10^3 kg/m^3 exist at the bottom of middle crust between Wenquan and Tanggemu. The density is 3.10× 10^3 kg/m^3 in lower crust. The shallowest depth of Moho interface is about 56 km, and the deepest one is about 74 km, the undulation of interface is large, the deep Moho is located in Xiachayu, Chayu, Nujiang, and Wenquan. The crustal density of eastern Tibetan plateau is larger than that of central section; the low velocity layers are located in middle crust and bottom in eastern Tibetan plateau and at the bottom of the upper crust in the central plateau.展开更多
Using the results of aftershock relocation, inversion on seismic waves and InSAR results, and surface rupture displacements obtained by geological survey after the earthquake, this paper constructs a fault model of th...Using the results of aftershock relocation, inversion on seismic waves and InSAR results, and surface rupture displacements obtained by geological survey after the earthquake, this paper constructs a fault model of the Yushu Ms7. 1 earthquake. Based on rectangular dislocation theory in an elastic-viscoelastic layered medium, we have simulated the co- seismic deformation and gravity change with gravitational effect considered. The pictures show that the absolute gravity measuring point is beside the extremum of coseismic gravity change, and the numerical value reaches 25.02 x 10-Sm. s-2. After a discussion about the gravity changes before the earthquake and the coherence consistency between two FG-5 absolute gravimeters, we think that the measured value 27.2 × 10^-8 m· s^-2 at Yushu station is coseismic gravity change. It＇s coincident with the simulation results based on dislocation theory. Therefore it is a good tool to test the near-field changes found by dislocation theory.展开更多
The next-generation gravity satellite mission equipped with the Cold Atom Interferometry(CAI)gradiometer has great potential for the Earth's gravity field estimation.Deploying a CAI gradiometer on the Chinese Tian...The next-generation gravity satellite mission equipped with the Cold Atom Interferometry(CAI)gradiometer has great potential for the Earth's gravity field estimation.Deploying a CAI gradiometer on the Chinese Tiangong Space Station launched for long-term Earth science research not only reduces the cost compared to a dual-satellite constellation but also enhances interdisciplinary collaboration in the Earth's gravity field detection.In this study,we conducted gravity gradient-based simulations to assess the contribution of deploying a CAI gradiometer on the Tiangong Space Station to collaboratively observe the Earth's gravity field with a polar-orbit gravity satellite.The simulation results demonstrate that whether utilizing V_(yy) component,three diagonal components or full components,the derived gravity field models show significant improvements within 100 degree and above 200 degree after incorporating Tiangong Space Station.In particular,the gravity field solution recovered from three diagonal components achieves the best accuracy.In the case of using diagonal components,the collaboration observation scheme effectively reduced the cumulative geoid height error by approximately 5.3 cm(300 d/o).In the spatial domain,the incorporation of the Tiangong Space Station primarily impacts the estimated gravity field within the orbital coverage area of the space station,and this effect is particularly pronounced when just employing V_(yy) component.However,due to the limitation of angular velocity observation inaccuracy associated with the CAI gradiometer in nadir mode,there is no substantial accuracy improvement observed above 200 degree when adding gradient components.展开更多
In this paper, regarding the actual conditions of a roller compacted concrete dam, three-dimensional finite element relocating mesh method is utilized to simulate and calculate the temperature field of the RCC dam dur...In this paper, regarding the actual conditions of a roller compacted concrete dam, three-dimensional finite element relocating mesh method is utilized to simulate and calculate the temperature field of the RCC dam during the construction stage and operating period. The calculation is well consistent with the actual construction process, the thin-layer pouring process the pouring temperature and all kinds of external loads involved being taken into account, By comparing and analyzing of the impact of the cold wave on the dam stress, important references are provided for the RCCD design and the temperature control during construction.展开更多
In this paper,we take the mid-temperature gravity heat pipe exchanger as the research object,simulate the fluid flow field,temperature field and the working state of heat pipe in the heat exchanger by Fluent software....In this paper,we take the mid-temperature gravity heat pipe exchanger as the research object,simulate the fluid flow field,temperature field and the working state of heat pipe in the heat exchanger by Fluent software.The effects of different operating parameters and fin parameters on the heat transfer performance of heat exchangers are studied.The results show that the heat transfer performance of the mid-temperature gravity heat pipe exchanger is the best when the fin spacing is between 5 mm and 6 mm,the height of the heat pipe is between 12 mm and 13 mm,and the inlet velocity of the fluid is between 2.5 m/s to 3 m/s.展开更多
The presence of random fissures has a great impact on rock slope stability.To investigate the failure modes and stability of rock slopes containing different types of pre-existing fissures,the fracture mark ξ was int...The presence of random fissures has a great impact on rock slope stability.To investigate the failure modes and stability of rock slopes containing different types of pre-existing fissures,the fracture mark ξ was introduced to improve the kernel function in the traditional smoothed particle dynamics(SPH) method,and a novel numerical method,the improved kernel of smoothed particle hydrodynamics(IKSPH),was proposed to realise the microscopic damage characteristics of particles.The ‘random fissure generating method' has been proposed for random fissure generation,and the gravity increase method has been embedded into the IKSPH program,thereby realising the stability analysis of rock slopes considering crack propagation processes.A typical steep rock slope is taken as a numerical simulation example considering the random distributions of preexisting fissures,and its failure modes as well as the stability under different conditions were simulated.The results show that the failure processes of the rock slope contain propagations of microcracks and then macrocrack penetrations.When the fissure length is short,shallow collapse failure modes can be observed;when the fissure length is long,the deep layer slide occurs,and the slope stability decreases with an increase in fissure length.The micro and macrocrack surfaces are basically consistent with pre-existing fissure angles,and the safety factor is the least at a fissure angle of 30°.The greater the fissure density,the greater the number of macrocracks,and the stability decreases with an increase in the number of pre-existing fissures.The research results can provide some references for disaster protection and understanding the failure laws of rock slopes.Meanwhile,combining the geological survey results with the numerical simulations and developing a high-performance IKSPH program will be a future research direction.展开更多
The prediction of bathymetry has advanced significantly with the development of satellite altimetry.However,the majority of its data originate from marine gravity anomaly.In this study,based on the expression of verti...The prediction of bathymetry has advanced significantly with the development of satellite altimetry.However,the majority of its data originate from marine gravity anomaly.In this study,based on the expression of vertical gravity gradient(VGG)of a rectangular prism,the governing equations for determining sea depths to invert bathymetry.The governing equation is solved by linearization through an iterative process,and numerical simulations verify its algorithm and its stability.We also study the processing methods of different interference errors.The regularization method improves the stability of the inversion process for errors.A piecewise bilinear interpolation function roughly replaces the low-frequency error,and numerical simulations show that the accuracy can be improved by 41.2%after this treatment.For variable ocean crust density,simulation simulations verify that the root-mean-square(RMS)error of prediction is approximately 5 m for the sea depth of 6 km if density is chosen as the average one.Finally,two test regions in the South China Sea are predicted and compared with ship soundings data,RMS errors of predictions are 71.1 m and 91.4 m,respectively.展开更多
Thanks to the quantum simulation,more and more problems in quantum mechanics which were previously inaccessible are now open to us.Capitalizing on the state-of-the-art techniques on quantum coherent control developed ...Thanks to the quantum simulation,more and more problems in quantum mechanics which were previously inaccessible are now open to us.Capitalizing on the state-of-the-art techniques on quantum coherent control developed in past few decades,e.g.,the high-precision quantum gate manipulating,the time-reversal harnessing,the high-fidelity state preparation and tomography,the nuclear magnetic resonance(NMR) system offers a unique platform for quantum simulation of many-body physics and high-energy physics.Here,we review the recent experimental progress and discuss the prospects for quantum simulation realized on NMR systems.展开更多
This paper reports on the potential use of video games as well as gaming engines in the domain of physics and artificial intelligence. Unreal Engine 4 (UE4) <a href="#ref1">[1]</a> is used to ren...This paper reports on the potential use of video games as well as gaming engines in the domain of physics and artificial intelligence. Unreal Engine 4 (UE4) <a href="#ref1">[1]</a> is used to render the history of the universe back in time to the quantum gravity era and then standard cosmology is assumed for its evolution until the appearance of life that was a simplified model of human-like evolution is rendered. The results of the simulations have a potential implication on the origin of life and matter and favorite the simulation hypothesis of the universe.展开更多
The objective of this paper is to present a new method for designing absorbing or non-reflective boundary conditions (ABC) or (NRBC), illustrated by the case study of the modelling of a solid body in water, specifical...The objective of this paper is to present a new method for designing absorbing or non-reflective boundary conditions (ABC) or (NRBC), illustrated by the case study of the modelling of a solid body in water, specifically the capillary gravity waves generated by its motion at the surface. The study analyses the flow of an inviscid, barotropic, and compressible fluid around the stationary solid body. The dynamic behaviour of the fluid is analysed using a two-dimensional coupled Neumann-Kelvin model extended with capillarity and inertia terms. For computational purposes, it is necessary to truncate the unbounded spatial domain with artificial boundaries and then introduce appropriate absorbing boundary conditions. The propagation of short wavelength waves in a convective fluid medium with significant differences in properties between the interior and the surface of the fluid presents a number of difficulties in the design of these conditions. The results are illustrated numerically and commented upon.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42475016,42192555 and 42305085)the China Postdoctoral Science Foundation(Grant No.2023M741615)the 2023 Graduate Research Innovation Project of Hunan Province(Grant No.CX20230011)。
文摘This paper investigates the impact of the model top and damping layer on the numerical simulation of tropical cyclones(TCs)and reveals the significant role of stratospheric gravity waves(SGWs).TCs can generate SGWs,which propagate upward and outward into the stratosphere.These SGWs can reach the damping layer,which is a consequence of the numerical scheme employed,where they can affect the tangential circulation through the dragging and forcing processes.In models with a higher top boundary,this tangential circulation develops far from the TC and has minimal direct impact on TC intensity.By comparison,in models with a lower top(e.g.,20 km),the damping layer is located just above the top of the TC.The SGW dragging in the damping layer and the consequent tangential force can thus induce ascent outside the eyewall,promote latent heat release,tilt the eyewall,and enlarge the inner-core radius.This process will reduce inner-core vorticity advection within the boundary layer,and eventually inhibits the intensification of the TC.This suggests that when the thickness of the damping layer is 5 km,the TC numerical model top height should be at least higher than 20 km to generate more accurate simulations.
基金supported by the Project of Stable Support for Youth Teams in Basic Research Field,Chinese Academy of Sciences(CASGrant No.YSBR-018)+2 种基金the B-type Strategic Priority Program of CAS(Grant No.XDB41000000)the National Natural Science Foundation of China(Grant No.42204165)the National Key Research and Development Program(Grant No.2022YFF0504400).
文摘In addition to being driven by tidal winds,the sporadic E(Es)layers are modulated by gravity waves(GWs),although the effects are not yet comprehensively understood.In this article,we discuss the effects of mesoscale GWs on the Es layers determined by using a newly developed model,MISE-1D(one-dimensional Model of Ionospheric Sporadic E),with low numerical dissipation and high resolution.Driven by the wind fields resolved by the high-resolution version of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension(WACCM-X),the MISE-1D simulation revealed that GWs significantly influence the evolution of the Es layer above 100 km but have a very limited effect at lower altitudes.The effects of GWs are diverse and complex,generally including the generation of fluctuating wavelike structures on the Es layer with frequencies similar to those of the GWs.The mesoscale GWs can also cause increases in the density of Es layers,or they can disperse or diffuse the Es layers and increase their thickness.In addition,the presence of GWs is a key factor in sustaining the Es layers in some cases.
基金The project supported by National Natural Science Foundation of China(No.51991364,51974347)the Major Scientific and Technological Projects of CNPC under Grant ZD2019-184-002。
文摘Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological storage.Based on the Navier-Stokes equation,component mass conservation equation,and fluid property-composition relationship,a mathematical model for pore-scale CO_(2) injection in oilsaturated porous media was developed in this study.The model can reflect the effects of gravity assistance,component diffusion,fluid density variation,and velocity change on EOR and CO_(2) storage.For nonhomogeneous porous media,the gravity influence and large density difference help to minimize the velocity difference between the main flow path and the surrounding area,thus improving the oil recovery and CO_(2) storage.Large CO_(2) injection angles and oil-CO_(2) density differences can increase the oil recovery by 22.6% and 4.2%,respectively,and increase CO_(2) storage by 37.9% and 4.7%,respectively.Component diffusion facilitates the transportation of the oil components from the low-velocity region to the main flow path,thereby reducing the oil/CO_(2) concentration difference within the porous media.Component diffusion can increase oil recovery and CO_(2) storage by 5.7% and 6.9%,respectively.In addition,combined with the component diffusion,a low CO_(2) injection rate creates a more uniform spatial distribution of the oil/CO_(2) component,resulting in increases of 9.5% oil recovery and 15.7% CO_(2) storage,respectively.This study provides theoretical support for improving the geological CO_(2) storage and EOR processes.
基金This paper is supported by the National 863 High Technology Development Plan Project (Grant No2006AA100301)the Programfor Changjiang Scholars and Innovative Research Teamin University (IRT-0420)
文摘This paper aims at investigation of the dynamic properties of gravity cage exposed to waves by use of a numerical model. The numerical model is developed, based on lumped mass method to set up the equations of motion of the whole cage; meanwhile the solutions of equations are solved by the Runge-Kutta-Vemer fifth-order and sixth-order method. Physical model tests have been carried out to examine the validity of the numerical model. The results by the numerical simulation agree well with the experimental data.
基金supported by the National Natural Science Foundation of China(Nos.41902273,41772338)the China Postdoctoral Science Foundation(No.2019M661986)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20190637)and the Jiangsu Planned Projects for Postdoctoral Research Funds(No.2019K194)support by the State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology(Nos.Z19007,Z19009).
文摘Lunar in-situ resource utilization(ISRU)has been put on the agenda by many countries.Due to the special material nature and low gravity environment,the lunar regolith demonstrates significantly different behavior from terrestrial geomaterials.However,the systematic understanding of its geotechnical behavior is now seriously restricted by the scarcity of lunar regolith and the difficulty in simulating lunar gravity.A new lunar regolith simulant,termed as China University of Mining and Technology Number One(CUMT-1),has been developed to recover properties of the lunar regolith and simulate the lunar gravity by adopting the recently advanced geotechnical magnetic-similitude-gravity model testing(GMMT)method.The CUMT-1 simulant was prepared by reproducing the in-situ formation and fragmentation of the lunar matrix,which plays a key role in the irregular particle morphology.The mineralogical compositions,particle morphology and gradation,specific gravity,bulk density,void ratio,shear strength,and compressibility were determined.After quantifying the magnetization and magnetic-similitude-gravity characteristics,an application of the cone penetration resistance under low gravity was further given.The obtained results are compared to the values known for lunar regolith samples and other simulants,which demonstrates promising characteristics for use in geotechnical engineering-based and scientificbased applications,especially considering the influence of lunar gravity.
基金supported by the National Natural Science Fundation of China(40574012)
文摘Surface co-seismic gravity changes and displacements caused by the Wenchuan Ms8.0 earthquake are calculated on the basis of the half-space dislocation theory and two fault models inversed, respectively, by Institute of Geophysics, CEA and USGS. The results show that 1 ） the dislocation consists of dip slip and rightlateral strike slip ;2 ）the co-seismic gravity change shows a four-quadrant pattern ,which is greatly controlled by the distribution of the vertical displacements, especially in the near-filed ; 3 ） the gravity change is generally less than 10 × 10^-8 ms^-2 in the far-field,but as high as several 100 × 10^-8 ms^-2 in the near-filed. These results basically agree with observational results.
基金support from the John Templeton Foundation,The Quantum Information Structure of Spacetime(QISS)Project(qiss.fr)(the opinions expressed in this paper are those of the authors and do not necessarily reflect the views of the John Templeton Foundation)(Grant No.61466)and QISS2(Grant No.62312).
文摘Detecting gravity-mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics.We report the result of a simulation of the phenomenon using a photonic platform.The simulation tests the idea of probing the quantum nature of a variable by using it to mediate entanglement and yields theoretical and experimental insights,clarifying the operational tools needed for future gravitational experiments.We employ three methods to test the presence of entanglement:the Bell test,entanglement witness,and quantum state tomography.We also simulate the alternative scenario predicted by gravitational collapse models or due to imperfections in the experimental setup and use quantum state tomography to certify the absence of entanglement.The simulation reinforces two main lessons:(1)which path information must be first encoded and subsequently coherently erased from the gravitational field and(2)performing a Bell test leads to stronger conclusions,certifying the existence of gravity-mediated nonlocality.
基金This paper was supported by the National Natural Science Foundation of China (Grant No.19972061)
文摘By the Volume of Fluid (VOF) multiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for high Reynolds numbers is demonstrated quantitatively by LES (the Large Eddy Simulation) turbulence model. The gravity currents are simulated for h not equal H as well as h = H, where h is the depth of the gravity current before the release and H is the depth of the intruded fluid. Uprising of swell occurs when a current flows horizontally into another lighter one for h not equal H. The problems under what condition the uprising of swell occurs and how long it takes are considered in this article. All the simulated results are in reasonable agreement with the experimental results available.
基金Supported by the National Natural Science Foundation of China (No. 40874036,No. 90814009,No. 40774011)the National Science & Technology Major Project of China (No. 2008ZX05008-006-062)
文摘The crustal structure of Xiachayu-Gonghe geophysical profile in eastern Tibetan plateau is simulated with Bouguer anomaly corrected for sediments and lithosphere. The forward simulation shows that the thickness of upper crust in eastem Tibetan plateau is about 20 km, and the density is 2.78 × 10^3 kg/m^3. The bottom interface of middle crust changes from 30 km to 40 km, the density of middle crust is 2.89 × 10^3 kg/m^3. The materials with low density of 2.78 × 10^3 kg/m^3 exist in middle crust, and those with high density of 3.33 × 10^3 kg/m^3 exist at the bottom of middle crust between Wenquan and Tanggemu. The density is 3.10× 10^3 kg/m^3 in lower crust. The shallowest depth of Moho interface is about 56 km, and the deepest one is about 74 km, the undulation of interface is large, the deep Moho is located in Xiachayu, Chayu, Nujiang, and Wenquan. The crustal density of eastern Tibetan plateau is larger than that of central section; the low velocity layers are located in middle crust and bottom in eastern Tibetan plateau and at the bottom of the upper crust in the central plateau.
基金funded by the National Natural Science Foundation of China(41104049)the Earthquake Situation Tracking,CEA(2012020207)Scientific Investigation of Yushu M S 7.1 Earthquake,CEA(2060302)
文摘Using the results of aftershock relocation, inversion on seismic waves and InSAR results, and surface rupture displacements obtained by geological survey after the earthquake, this paper constructs a fault model of the Yushu Ms7. 1 earthquake. Based on rectangular dislocation theory in an elastic-viscoelastic layered medium, we have simulated the co- seismic deformation and gravity change with gravitational effect considered. The pictures show that the absolute gravity measuring point is beside the extremum of coseismic gravity change, and the numerical value reaches 25.02 x 10-Sm. s-2. After a discussion about the gravity changes before the earthquake and the coherence consistency between two FG-5 absolute gravimeters, we think that the measured value 27.2 × 10^-8 m· s^-2 at Yushu station is coseismic gravity change. It＇s coincident with the simulation results based on dislocation theory. Therefore it is a good tool to test the near-field changes found by dislocation theory.
基金National Key R&D Program of China(2021YFB3900101)the National Natural Science Foundation of China(42174099 and 42192532)It is also partly supported by the Fundamental Research Funds for the Central Universities.
文摘The next-generation gravity satellite mission equipped with the Cold Atom Interferometry(CAI)gradiometer has great potential for the Earth's gravity field estimation.Deploying a CAI gradiometer on the Chinese Tiangong Space Station launched for long-term Earth science research not only reduces the cost compared to a dual-satellite constellation but also enhances interdisciplinary collaboration in the Earth's gravity field detection.In this study,we conducted gravity gradient-based simulations to assess the contribution of deploying a CAI gradiometer on the Tiangong Space Station to collaboratively observe the Earth's gravity field with a polar-orbit gravity satellite.The simulation results demonstrate that whether utilizing V_(yy) component,three diagonal components or full components,the derived gravity field models show significant improvements within 100 degree and above 200 degree after incorporating Tiangong Space Station.In particular,the gravity field solution recovered from three diagonal components achieves the best accuracy.In the case of using diagonal components,the collaboration observation scheme effectively reduced the cumulative geoid height error by approximately 5.3 cm(300 d/o).In the spatial domain,the incorporation of the Tiangong Space Station primarily impacts the estimated gravity field within the orbital coverage area of the space station,and this effect is particularly pronounced when just employing V_(yy) component.However,due to the limitation of angular velocity observation inaccuracy associated with the CAI gradiometer in nadir mode,there is no substantial accuracy improvement observed above 200 degree when adding gradient components.
文摘In this paper, regarding the actual conditions of a roller compacted concrete dam, three-dimensional finite element relocating mesh method is utilized to simulate and calculate the temperature field of the RCC dam during the construction stage and operating period. The calculation is well consistent with the actual construction process, the thin-layer pouring process the pouring temperature and all kinds of external loads involved being taken into account, By comparing and analyzing of the impact of the cold wave on the dam stress, important references are provided for the RCCD design and the temperature control during construction.
文摘In this paper,we take the mid-temperature gravity heat pipe exchanger as the research object,simulate the fluid flow field,temperature field and the working state of heat pipe in the heat exchanger by Fluent software.The effects of different operating parameters and fin parameters on the heat transfer performance of heat exchangers are studied.The results show that the heat transfer performance of the mid-temperature gravity heat pipe exchanger is the best when the fin spacing is between 5 mm and 6 mm,the height of the heat pipe is between 12 mm and 13 mm,and the inlet velocity of the fluid is between 2.5 m/s to 3 m/s.
基金funded by the the National Natural Science Fund (Grant No.U1765204,51409170)the Fundamental Research Funds for the Central Universities of China (B210203078)。
文摘The presence of random fissures has a great impact on rock slope stability.To investigate the failure modes and stability of rock slopes containing different types of pre-existing fissures,the fracture mark ξ was introduced to improve the kernel function in the traditional smoothed particle dynamics(SPH) method,and a novel numerical method,the improved kernel of smoothed particle hydrodynamics(IKSPH),was proposed to realise the microscopic damage characteristics of particles.The ‘random fissure generating method' has been proposed for random fissure generation,and the gravity increase method has been embedded into the IKSPH program,thereby realising the stability analysis of rock slopes considering crack propagation processes.A typical steep rock slope is taken as a numerical simulation example considering the random distributions of preexisting fissures,and its failure modes as well as the stability under different conditions were simulated.The results show that the failure processes of the rock slope contain propagations of microcracks and then macrocrack penetrations.When the fissure length is short,shallow collapse failure modes can be observed;when the fissure length is long,the deep layer slide occurs,and the slope stability decreases with an increase in fissure length.The micro and macrocrack surfaces are basically consistent with pre-existing fissure angles,and the safety factor is the least at a fissure angle of 30°.The greater the fissure density,the greater the number of macrocracks,and the stability decreases with an increase in the number of pre-existing fissures.The research results can provide some references for disaster protection and understanding the failure laws of rock slopes.Meanwhile,combining the geological survey results with the numerical simulations and developing a high-performance IKSPH program will be a future research direction.
基金funded jointly by the National Nature Science Funds of China(No.42274010)the Fundamental Research Funds for the Central Universities(Nos.2023000540,2023000407).
文摘The prediction of bathymetry has advanced significantly with the development of satellite altimetry.However,the majority of its data originate from marine gravity anomaly.In this study,based on the expression of vertical gravity gradient(VGG)of a rectangular prism,the governing equations for determining sea depths to invert bathymetry.The governing equation is solved by linearization through an iterative process,and numerical simulations verify its algorithm and its stability.We also study the processing methods of different interference errors.The regularization method improves the stability of the inversion process for errors.A piecewise bilinear interpolation function roughly replaces the low-frequency error,and numerical simulations show that the accuracy can be improved by 41.2%after this treatment.For variable ocean crust density,simulation simulations verify that the root-mean-square(RMS)error of prediction is approximately 5 m for the sea depth of 6 km if density is chosen as the average one.Finally,two test regions in the South China Sea are predicted and compared with ship soundings data,RMS errors of predictions are 71.1 m and 91.4 m,respectively.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0308100)the National Natural Science Foundation of China(Grant Nos.12075110,11905099,11605005,11875159,and U1801661)+2 种基金Guangdong Basic and Applied Basic Research Foundation,China(Grant No.2019A1515011383)Science,Technology and Innovation Commission of Shenzhen Municipality(Grant Nos.ZDSYS20170303165926217,JCYJ20170412152620376,and JCYJ20180302174036418)Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2016ZT06D348)。
文摘Thanks to the quantum simulation,more and more problems in quantum mechanics which were previously inaccessible are now open to us.Capitalizing on the state-of-the-art techniques on quantum coherent control developed in past few decades,e.g.,the high-precision quantum gate manipulating,the time-reversal harnessing,the high-fidelity state preparation and tomography,the nuclear magnetic resonance(NMR) system offers a unique platform for quantum simulation of many-body physics and high-energy physics.Here,we review the recent experimental progress and discuss the prospects for quantum simulation realized on NMR systems.
文摘This paper reports on the potential use of video games as well as gaming engines in the domain of physics and artificial intelligence. Unreal Engine 4 (UE4) <a href="#ref1">[1]</a> is used to render the history of the universe back in time to the quantum gravity era and then standard cosmology is assumed for its evolution until the appearance of life that was a simplified model of human-like evolution is rendered. The results of the simulations have a potential implication on the origin of life and matter and favorite the simulation hypothesis of the universe.
文摘The objective of this paper is to present a new method for designing absorbing or non-reflective boundary conditions (ABC) or (NRBC), illustrated by the case study of the modelling of a solid body in water, specifically the capillary gravity waves generated by its motion at the surface. The study analyses the flow of an inviscid, barotropic, and compressible fluid around the stationary solid body. The dynamic behaviour of the fluid is analysed using a two-dimensional coupled Neumann-Kelvin model extended with capillarity and inertia terms. For computational purposes, it is necessary to truncate the unbounded spatial domain with artificial boundaries and then introduce appropriate absorbing boundary conditions. The propagation of short wavelength waves in a convective fluid medium with significant differences in properties between the interior and the surface of the fluid presents a number of difficulties in the design of these conditions. The results are illustrated numerically and commented upon.
