A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques inclu...A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques include obtaining gravity data from the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE),creating seismic profiles,analyzing the receiver functions of seismic data,obtaining information from boreholes,and providing geological interpretations.GOCE satellite gravity data were processed to construct a preliminary model based on nonlinear inversions of the data.A regional crustal thickness model was developed using receiver functions,seismic refraction profiles,and geological insights.The inverted model was validated using borehole data and compared with seismic estimates.The model exhibited strong consistency and revealed a correlation between crustal thickness,geology,and tectonics of Egypt.It showed that the shallowest depths of the Moho are located in the north along the Mediterranean Sea and in the eastern part along the Red Sea,reflecting an oceanic plate with a thin,high-density crust.The deepest Moho depths are located in the southwestern part of Egypt,Red Sea coastal mountains,and Sinai Peninsula.The obtained 3D model of crustal thickness provided finely detailed Moho depth estimates that aligned closely with geology and tectonic characteristics of Egypt,contributing valuable insights into the subsurface structure and tectonic processes of region.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
The meteor radar can detect the zenith angle,azimuth,radial velocity,and altitude of meteor trails so that one can invert the wind profiles in the mesosphere and low thermosphere(MLT)region,based on the Interferometri...The meteor radar can detect the zenith angle,azimuth,radial velocity,and altitude of meteor trails so that one can invert the wind profiles in the mesosphere and low thermosphere(MLT)region,based on the Interferometric and Doppler techniques.In this paper,the horizontal wind field,gravity wave(GW)disturbance variance,and GW fluxes are analyzed through the meteor radar observation from 2012−2022,at Mohe(53.5°N,122.4°E)and Zuoling(30.5°N,114.6°E)stations of the(Chinese)Meridian Project.The Lomb−Scargle periodogram method has been utilized to analyze the periodic variations for time series with observational data gaps.The results show that the zonal winds at both stations are eastward dominated,while the meridional winds are southward dominated.The variance of GW disturbances in the zonal and meridional directions increases gradually with height,and there is a strong pattern of annual variation.The zonal momentum flux of GW changes little with height,showing weak annual variation.The meridional GW flux varies gradually from northward to southward with height,and the annual periodicity is stronger.For both stations,the maximum values of zonal and meridional wind occur close to the peak heights of GW flux,with opposite directions.This observational evidence is consistent with the filtering theory.The horizontal wind velocity,GW flux,and disturbance variance of the GW at Mohe are overall smaller than those at Zuoling,indicating weaker activities in the MLT at Mohe.The power spectral density(PSD)calculated by the Lomb−Scargle periodogram shows that there are 12-month period and 6-month period in horizontal wind field,GW disturbance variance and GW flux at both stations,and especially there is also a 4-month cycle in the disturbance variance.The PSD of the 12-month and 6-month cycles exhibits maximum values below 88 km and above 94 km.展开更多
To decipher both shallow and deeper structural features that may control the emplacement of Kimberlite/Lamproite bodies in basement-exposed and covered areas, a detailed gravity survey was conducted on the northern ba...To decipher both shallow and deeper structural features that may control the emplacement of Kimberlite/Lamproite bodies in basement-exposed and covered areas, a detailed gravity survey was conducted on the northern bank of the Krishna River in the Kollarpur region of the Proterozoic Cuddapah Basin, within the Eastern Dharwar Craton. The study revealed an overall basement disposition dipping from south to north, controlled by a set of parallel E-W and NW-SE trending faults. In the northeastern part of the study area, the high-gravity zone corresponds to high-density source rocks at both shallow and deeper levels within the granite-gneissic basement. The residual gravity map highlights the disposition of high-density shallow source bodies as elliptical highs, located at Narlapur, Kalwakole, and Yelur in the eastern part. These residual gravity highs correspond to enclaves of amphibolite schist and BIF bands within granite-gneissic rocks. In the covered region of the southern part, the overall gravity low zone indicates the distribution of sediments with a thickness of about 1 km. Several NW-SE, N-S, NE-SW, and E-W structural features were delineated from the gravity survey. A major E-W gravity gradient along the northern margin of the Cuddapah and Kurnool groups of sediments is interpreted as a deep-rooted boundary fault. Parallel to this boundary fault, two NW-SE gravity gradients were identified in the northern and central parts within the Archean granite-gneissic basement rocks. Depth extensions of these major structures exceed 1 km. The N-S and NE-SW structures, although shorter in strike length, intersect with the major NW-SE and E-W structures. Some of these intersection zones correspond to known Kimberlite/Lamproite occurrences in both covered and basement-exposed areas. Based on these findings, potential loci for Kimberlite/Lamproite exploration have been delineated along the northern bank of the Krishna River in the Kollarpur region.展开更多
We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. B...We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.展开更多
Quantum gravity is an attempt to resolve incompatibilities between general relativity and quantum theory. Primordial field theory incorporates gravity and electrodynamics and has derived fermion mass gap, half integra...Quantum gravity is an attempt to resolve incompatibilities between general relativity and quantum theory. Primordial field theory incorporates gravity and electrodynamics and has derived fermion mass gap, half integral spin, and fractional charges. This paper extends PFT to hadron physics with a “solenoidal flux”-based explanation of quark confinement differing significantly from Lattice QCD “color flux”-based construction. The theory is presented qualitatively and used to predict hadronic and nuclear properties. Electrodynamic-based analogies help yield numerical results far more intuitively than corresponding QCD results. The origins of QCD and PFT are discussed. A more quantitative description of hadron dynamics is in progress.展开更多
We apply the WKB approximation method,matrix method,and finite difference method to study the gravitational quasi-normal modes of charged spherically symmetric black holes surrounded by quintessence fluid in Rastall g...We apply the WKB approximation method,matrix method,and finite difference method to study the gravitational quasi-normal modes of charged spherically symmetric black holes surrounded by quintessence fluid in Rastall gravity.By comparing the spherically symmetric spacetime metric of charged black holes surrounded by quintessence fluid in Rastall gravity with that of general relativity,we can find that the modifications to general relativity in this modified gravity theory can be described by parameters such asλ,Q,and C_(a),etc.In four-dimensional spacetime,we investigate the impact of charge Q and parameter C_(a) on the gravitational quasi-normal modes of charged black holes surrounded by quintessence field in Rastall gravity.The aim is to search for observational evidence of such black holes in astrophysical observations and,consequently,test the validity of Rastall theory.In five-dimensional(5D)spacetime,we study the impact of the parameter C_(a) on the gravitational quasi-normal modes of Rastall black holes surrounded by quintessence field and summarize the corresponding variation patterns.展开更多
A new suspension gravity compensation system has been developed to alleviate the gravity effects on a two-dimensional(2D)deployable mechanism for ground verification.Considering the rigid-flexible coupling of both the...A new suspension gravity compensation system has been developed to alleviate the gravity effects on a two-dimensional(2D)deployable mechanism for ground verification.Considering the rigid-flexible coupling of both the rotating servo and the suspension system,a multi-body dynamic model simulating their integration is established using Lagrange’s equation.To mitigate instantaneous impact forces due to significant non-plumb effects from passive following in the horizontal direction,an elastic element is added in series with the rope in the vertical suspension system.The dynamic response of this elastic element relative to the rotating servo system is analyzed by the ADAMS software.Simulation results show that the compensating error decreases significantly from 45%to 0.31%when incorporating elastic elements compared to scenarios without such elements.Additionally,low-stiffness elastic elements demonstrate a higher compensating error than high-stiffness ones.A spring with a stiffness coefficient of 6 N/mm is selected in the experiment,ensuring that compensating error meets the design specification of 5%.展开更多
The gravity p-median model is an important improvement to the widely-used p-median model. However, there is still a debate on its validity in empirical applications. Previous studies even doubt the significance of the...The gravity p-median model is an important improvement to the widely-used p-median model. However, there is still a debate on its validity in empirical applications. Previous studies even doubt the significance of the gravity p-median model. Using a case study of tertiary hospitals in Shenzhen, China, this study re-examines the difference between the gravity p-median model with the p-median model, by decomposing the difference between the two models into gravity rule and variant attraction. This study also proposes a modified gravity p-median model by incorporating a distance threshold. The empirical results support the validity of the gravity p-median model, and also reveal that only when the attractions of candidate facility locations are variable will the gravity p-median model lead to different results with the p-median model. The difference between the modified gravity p-median model and the gravity p-median model is also examined. Moreover, the impacts of the distance-decay parameter and distance threshold on solutions are investigated. Results indicate that a larger distance-decay parameter tends to result in a more dispersed distribution of optimal facilities and a smaller average travel time, and a smaller distance threshold can better promote the spatial equity of facilities. The proposed method can also be applied in studies of other types of facilities or in other areas.展开更多
Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The ...Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important issue.Using temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW events.During the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°W.During these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward extension.The E_(p)usually increased,while partially filtered by the eastward zonal winds.When zonal winds weakened or turned westward,E_(p)began to strengthen.After SSWs,the E_(p)usually decreased.These observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work.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
To clarify the formation and distribution of feldspar dissolution pores and predict the distribution of high-quality reservoir in gravity flow sandstone of the 7^(th) member of Triassic Yanchang Formation(Chang 7 Memb...To clarify the formation and distribution of feldspar dissolution pores and predict the distribution of high-quality reservoir in gravity flow sandstone of the 7^(th) member of Triassic Yanchang Formation(Chang 7 Member)in the Ordos Basin,thin sections,scanning electron microscopy,energy spectrum analysis,X-ray diffraction whole rock analysis,and dissolution experiments are employed in this study to investigate the characteristics and control factors of feldspar dissolution pores.The results show that:(1)Three types of diagenetic processes are observed in the feldspar of Chang 7 sandstone in the study area:secondary overgrowth of feldspar,replacement by clay and calcite,and dissolution of detrital feldspar.(2)The feldspar dissolution of Chang 7 tight sandstone is caused by organic acid,and is further affected by the type of feldspar,the degree of early feldspar alteration,and the buffering effect of mica debris on organic acid.(3)Feldspars have varying degrees of dissolution.Potassium feldspar is more susceptible to dissolution than plagioclase.Among potassium feldspar,orthoclase is more soluble than microcline,and unaltered feldspar is more soluble than early kaolinized or sericitized feldspar.(4)The dissolution experiment demonstrated that the presence of mica can hinder the dissolution of feldspar.Mica of the same mass has a significantly stronger capacity to consume organic acids than feldspar.(5)Dissolution pores in feldspar of Chang 7 Member are more abundant in areas with low mica content,and they improve the reservoir physical properties,while in areas with high mica content,the number of feldspar dissolution pores decreases significantly.展开更多
We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation O...We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)satellite.Owing to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan Mountains.The land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper stratosphere.At 40°N/S,the peaks were mainly above the topographic regions during the winter.At 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain waves.Near the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from convection.Our results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic distributions.We found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.展开更多
The gravity gradient anomaly zone is produced due to density diff erences on both sides of a fault.Tracking of extreme points enables the characterization and description of fault locations.However,for some deep-seate...The gravity gradient anomaly zone is produced due to density diff erences on both sides of a fault.Tracking of extreme points enables the characterization and description of fault locations.However,for some deep-seated faults with large burial depths and secondary faults with moderate burial depths,the gravity horizontal total gradient anomaly must be enhanced using the concept of dip angle to strengthen the weak anomaly extraction for the identification of more fault information.This method was used to predict five regional deep-seated faults and six secondary faults in the Miquan region.The fracture plane extends in a near north-northeast direction;that is,it mostly expands out of the study area,spreads out in a trumpet shape to the southwest,and converges to the northeast.Fracture activity is an important factor in controlling structural units or local structures.The Miquan block is located in a complex structural zone in front of the Bogeda Mountains,which have very complex surface and subsurface geological conditions,and seismic data are unideal.Therefore,fracture prediction results using gravity data are important in-depth understanding of the structure in this area.展开更多
It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals ex...It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.展开更多
This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this g...This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this goal,the Krori and Barua arrangement for spherically symmetric components of the line element is incorporated.We explore the field equations by selecting appropriate off-diagonal tetrad fields.Born-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are used.The Born-Infeld gravity was the first modified teleparallel gravity to discuss inflation.We use the linear equation of state pr=ξρto separate the quintessence density.After obtaining the field equations,we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models.We use observational data,such as the mass and radius of the compact star candidates PSRJ 1416-2230,Cen X-3,&4U 1820-30,to ensure the physical plausibility of our findings.展开更多
Ground penetrating radar (GPR) surveys have being applied to investigate very near-surface stratification of sedimentary units in coastal plains and to define their depositional conditions. This paper presents, howeve...Ground penetrating radar (GPR) surveys have being applied to investigate very near-surface stratification of sedimentary units in coastal plains and to define their depositional conditions. This paper presents, however, low-frequency GPR survey to investigate fault-related depositional systems at greater depths. The Quinta-Cassino area in the Rio Grande do Sul Coastal Plain (RGSCP, Brazil) shows a wide strandplain that is made off by very long, continuous, and linear geomorphic features (beach ridges). This strandplain extends for ~70 km southward. The beach ridges show low-angle truncations against the Quinta escarpment, and also truncations in the strandplain. The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;previous model assumes that no deformational episode occurred in RGSCP. The geophysical and geological surveys carried out in this area showed the existence of listric fault controlling the beach ridges in the escarpments and hanging-wall blocks. The radargrams could distinguish Pleistocene basement unit anticlockwise rotation, thickening of beach ridges radarfacies close to listric normal faults, and horst structures. These deformational features indicate that the extensional zone of a large-scale gravity-driven structure controlled the mechanical subsidence, the Holocene sedimentation and its stratigraphic and geomorphic features in the Quinta-Cassino area to build up an asymmetric delta. The results point to a new approach in dealing with RGSCP Holocene evolution.展开更多
Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the...Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the seafloor has been precisely modeled to date,and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data.In this study,we introduce a pretrained visual geometry group network(VGGNet)method based on deep learning.To apply this method,we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter,which has a larger spatial coverage,based on the former,which is considered the true value and is more accurate.After obtaining the corrected high-precision gravity model,it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation.We choose four data pairs collected from different environments,i.e.,the Southern Ocean,Pacific Ocean,Atlantic Ocean and Caribbean Sea,to evaluate the topographic correction results of the model.The experiments show that the coefficient of determination(R~2)reaches 0.834 among the results of the four experimental groups,signifying a high correlation.The standard deviation and normalized root mean square error are also evaluated,and the accuracy of their performance improved by up to 24.2%compared with similar research done in recent years.The evaluation of the R^(2) values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research.Finally,the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21%within 1%of the total water depths,which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results.展开更多
This article describes an extension of the theory of vortices to electromagnetic types with a start point from known fluid systems. From this, properties of gravity-generating objects (particles and black holes) can b...This article describes an extension of the theory of vortices to electromagnetic types with a start point from known fluid systems. From this, properties of gravity-generating objects (particles and black holes) can be derived, which can also describe their possible interior. This also leads to questions about stability, which are then addressed and ultimately lead to considerations of black holes and their possible internal structure. The results fit into the observable areas and can also be directly verified because they were analytically calculated in SI units.展开更多
文摘A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques include obtaining gravity data from the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE),creating seismic profiles,analyzing the receiver functions of seismic data,obtaining information from boreholes,and providing geological interpretations.GOCE satellite gravity data were processed to construct a preliminary model based on nonlinear inversions of the data.A regional crustal thickness model was developed using receiver functions,seismic refraction profiles,and geological insights.The inverted model was validated using borehole data and compared with seismic estimates.The model exhibited strong consistency and revealed a correlation between crustal thickness,geology,and tectonics of Egypt.It showed that the shallowest depths of the Moho are located in the north along the Mediterranean Sea and in the eastern part along the Red Sea,reflecting an oceanic plate with a thin,high-density crust.The deepest Moho depths are located in the southwestern part of Egypt,Red Sea coastal mountains,and Sinai Peninsula.The obtained 3D model of crustal thickness provided finely detailed Moho depth estimates that aligned closely with geology and tectonic characteristics of Egypt,contributing valuable insights into the subsurface structure and tectonic processes of region.
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supported by the Fundamental Research Funds for the Central Universities,CHD(NO.300102263205 and NO.300102264916)the West Light Cross-Disciplinary Innovation team of Chinese Academy of Sciences(NO.E1294301).supported by the Fundamental Research Funds for the Central Universities,CHD(NO.300102263205 and NO.300102264916)the West Light Cross-Disciplinary Innovation team of Chinese Academy of Sciences(NO.E1294301).
文摘The meteor radar can detect the zenith angle,azimuth,radial velocity,and altitude of meteor trails so that one can invert the wind profiles in the mesosphere and low thermosphere(MLT)region,based on the Interferometric and Doppler techniques.In this paper,the horizontal wind field,gravity wave(GW)disturbance variance,and GW fluxes are analyzed through the meteor radar observation from 2012−2022,at Mohe(53.5°N,122.4°E)and Zuoling(30.5°N,114.6°E)stations of the(Chinese)Meridian Project.The Lomb−Scargle periodogram method has been utilized to analyze the periodic variations for time series with observational data gaps.The results show that the zonal winds at both stations are eastward dominated,while the meridional winds are southward dominated.The variance of GW disturbances in the zonal and meridional directions increases gradually with height,and there is a strong pattern of annual variation.The zonal momentum flux of GW changes little with height,showing weak annual variation.The meridional GW flux varies gradually from northward to southward with height,and the annual periodicity is stronger.For both stations,the maximum values of zonal and meridional wind occur close to the peak heights of GW flux,with opposite directions.This observational evidence is consistent with the filtering theory.The horizontal wind velocity,GW flux,and disturbance variance of the GW at Mohe are overall smaller than those at Zuoling,indicating weaker activities in the MLT at Mohe.The power spectral density(PSD)calculated by the Lomb−Scargle periodogram shows that there are 12-month period and 6-month period in horizontal wind field,GW disturbance variance and GW flux at both stations,and especially there is also a 4-month cycle in the disturbance variance.The PSD of the 12-month and 6-month cycles exhibits maximum values below 88 km and above 94 km.
文摘To decipher both shallow and deeper structural features that may control the emplacement of Kimberlite/Lamproite bodies in basement-exposed and covered areas, a detailed gravity survey was conducted on the northern bank of the Krishna River in the Kollarpur region of the Proterozoic Cuddapah Basin, within the Eastern Dharwar Craton. The study revealed an overall basement disposition dipping from south to north, controlled by a set of parallel E-W and NW-SE trending faults. In the northeastern part of the study area, the high-gravity zone corresponds to high-density source rocks at both shallow and deeper levels within the granite-gneissic basement. The residual gravity map highlights the disposition of high-density shallow source bodies as elliptical highs, located at Narlapur, Kalwakole, and Yelur in the eastern part. These residual gravity highs correspond to enclaves of amphibolite schist and BIF bands within granite-gneissic rocks. In the covered region of the southern part, the overall gravity low zone indicates the distribution of sediments with a thickness of about 1 km. Several NW-SE, N-S, NE-SW, and E-W structural features were delineated from the gravity survey. A major E-W gravity gradient along the northern margin of the Cuddapah and Kurnool groups of sediments is interpreted as a deep-rooted boundary fault. Parallel to this boundary fault, two NW-SE gravity gradients were identified in the northern and central parts within the Archean granite-gneissic basement rocks. Depth extensions of these major structures exceed 1 km. The N-S and NE-SW structures, although shorter in strike length, intersect with the major NW-SE and E-W structures. Some of these intersection zones correspond to known Kimberlite/Lamproite occurrences in both covered and basement-exposed areas. Based on these findings, potential loci for Kimberlite/Lamproite exploration have been delineated along the northern bank of the Krishna River in the Kollarpur region.
文摘We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.
文摘Quantum gravity is an attempt to resolve incompatibilities between general relativity and quantum theory. Primordial field theory incorporates gravity and electrodynamics and has derived fermion mass gap, half integral spin, and fractional charges. This paper extends PFT to hadron physics with a “solenoidal flux”-based explanation of quark confinement differing significantly from Lattice QCD “color flux”-based construction. The theory is presented qualitatively and used to predict hadronic and nuclear properties. Electrodynamic-based analogies help yield numerical results far more intuitively than corresponding QCD results. The origins of QCD and PFT are discussed. A more quantitative description of hadron dynamics is in progress.
基金Project supported by the National Natural Science Foundation of China(Grant No.42230207)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Grant No.G1323523064)。
文摘We apply the WKB approximation method,matrix method,and finite difference method to study the gravitational quasi-normal modes of charged spherically symmetric black holes surrounded by quintessence fluid in Rastall gravity.By comparing the spherically symmetric spacetime metric of charged black holes surrounded by quintessence fluid in Rastall gravity with that of general relativity,we can find that the modifications to general relativity in this modified gravity theory can be described by parameters such asλ,Q,and C_(a),etc.In four-dimensional spacetime,we investigate the impact of charge Q and parameter C_(a) on the gravitational quasi-normal modes of charged black holes surrounded by quintessence field in Rastall gravity.The aim is to search for observational evidence of such black holes in astrophysical observations and,consequently,test the validity of Rastall theory.In five-dimensional(5D)spacetime,we study the impact of the parameter C_(a) on the gravitational quasi-normal modes of Rastall black holes surrounded by quintessence field and summarize the corresponding variation patterns.
文摘A new suspension gravity compensation system has been developed to alleviate the gravity effects on a two-dimensional(2D)deployable mechanism for ground verification.Considering the rigid-flexible coupling of both the rotating servo and the suspension system,a multi-body dynamic model simulating their integration is established using Lagrange’s equation.To mitigate instantaneous impact forces due to significant non-plumb effects from passive following in the horizontal direction,an elastic element is added in series with the rope in the vertical suspension system.The dynamic response of this elastic element relative to the rotating servo system is analyzed by the ADAMS software.Simulation results show that the compensating error decreases significantly from 45%to 0.31%when incorporating elastic elements compared to scenarios without such elements.Additionally,low-stiffness elastic elements demonstrate a higher compensating error than high-stiffness ones.A spring with a stiffness coefficient of 6 N/mm is selected in the experiment,ensuring that compensating error meets the design specification of 5%.
基金Supported by the Urban China Initiative (UCI) through the UCI grant 2017
文摘The gravity p-median model is an important improvement to the widely-used p-median model. However, there is still a debate on its validity in empirical applications. Previous studies even doubt the significance of the gravity p-median model. Using a case study of tertiary hospitals in Shenzhen, China, this study re-examines the difference between the gravity p-median model with the p-median model, by decomposing the difference between the two models into gravity rule and variant attraction. This study also proposes a modified gravity p-median model by incorporating a distance threshold. The empirical results support the validity of the gravity p-median model, and also reveal that only when the attractions of candidate facility locations are variable will the gravity p-median model lead to different results with the p-median model. The difference between the modified gravity p-median model and the gravity p-median model is also examined. Moreover, the impacts of the distance-decay parameter and distance threshold on solutions are investigated. Results indicate that a larger distance-decay parameter tends to result in a more dispersed distribution of optimal facilities and a smaller average travel time, and a smaller distance threshold can better promote the spatial equity of facilities. The proposed method can also be applied in studies of other types of facilities or in other areas.
基金the National Science Foundation of Hunan Province,China(Grant No.2022JJ40471)the Research Foundation of the Education Bureau of Hunan Province,China(Grant No.22B0345)the Key Laboratory of Geospace Envi-ronment,Chinese Academy of Sciences,University of Science&Technology of China(Grant No.GE2023-01).
文摘Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important issue.Using temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW events.During the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°W.During these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward extension.The E_(p)usually increased,while partially filtered by the eastward zonal winds.When zonal winds weakened or turned westward,E_(p)began to strengthen.After SSWs,the E_(p)usually decreased.These observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work.
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Supported by the National Natural Science Foundation of China(42202176)CNPC-Southwest University of Petroleum Innovation Consortium Cooperation Project(2020CX050103).
文摘To clarify the formation and distribution of feldspar dissolution pores and predict the distribution of high-quality reservoir in gravity flow sandstone of the 7^(th) member of Triassic Yanchang Formation(Chang 7 Member)in the Ordos Basin,thin sections,scanning electron microscopy,energy spectrum analysis,X-ray diffraction whole rock analysis,and dissolution experiments are employed in this study to investigate the characteristics and control factors of feldspar dissolution pores.The results show that:(1)Three types of diagenetic processes are observed in the feldspar of Chang 7 sandstone in the study area:secondary overgrowth of feldspar,replacement by clay and calcite,and dissolution of detrital feldspar.(2)The feldspar dissolution of Chang 7 tight sandstone is caused by organic acid,and is further affected by the type of feldspar,the degree of early feldspar alteration,and the buffering effect of mica debris on organic acid.(3)Feldspars have varying degrees of dissolution.Potassium feldspar is more susceptible to dissolution than plagioclase.Among potassium feldspar,orthoclase is more soluble than microcline,and unaltered feldspar is more soluble than early kaolinized or sericitized feldspar.(4)The dissolution experiment demonstrated that the presence of mica can hinder the dissolution of feldspar.Mica of the same mass has a significantly stronger capacity to consume organic acids than feldspar.(5)Dissolution pores in feldspar of Chang 7 Member are more abundant in areas with low mica content,and they improve the reservoir physical properties,while in areas with high mica content,the number of feldspar dissolution pores decreases significantly.
基金the National Natural Science Foundation of China(Grant Nos.41831073,42174196,and 42374205)the Project of Stable Support for Youth Team in Basic Research Field,Chinese Academy of Sciences(CAS+4 种基金Grant No.YSBR-018)the Informatization Plan of CAS(Grant No.CAS-WX2021PY-0101)the Youth Cross Team Scientific Research project of the Chinese Academy of Sciences(Grant No.JCTD-2021-10)the Open Research Project of Large Research Infrastructures of CAS titled“Study on the Interaction Between Low-/Mid-Latitude Atmosphere and Ionosphere Based on the Chinese Meridian Project.”This work was also supported in part by the Specialized Research Fund and the Open Research Program of the State Key Laboratory of Space Weather.
文摘We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)satellite.Owing to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan Mountains.The land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper stratosphere.At 40°N/S,the peaks were mainly above the topographic regions during the winter.At 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain waves.Near the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from convection.Our results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic distributions.We found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.
基金supported by the Sinopec Science and Technology Research Project(No.P22161 and No.24029).
文摘The gravity gradient anomaly zone is produced due to density diff erences on both sides of a fault.Tracking of extreme points enables the characterization and description of fault locations.However,for some deep-seated faults with large burial depths and secondary faults with moderate burial depths,the gravity horizontal total gradient anomaly must be enhanced using the concept of dip angle to strengthen the weak anomaly extraction for the identification of more fault information.This method was used to predict five regional deep-seated faults and six secondary faults in the Miquan region.The fracture plane extends in a near north-northeast direction;that is,it mostly expands out of the study area,spreads out in a trumpet shape to the southwest,and converges to the northeast.Fracture activity is an important factor in controlling structural units or local structures.The Miquan block is located in a complex structural zone in front of the Bogeda Mountains,which have very complex surface and subsurface geological conditions,and seismic data are unideal.Therefore,fracture prediction results using gravity data are important in-depth understanding of the structure in this area.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the National Natural Science Foundation of China(Grant No.42174101,41974023)+1 种基金the Open Fund of Hubei Luojia Laboratory(Grant No.S22H640201)(Germany)The Offshore International Science and Technology Cooperation Center of Frontier Technology of Geodesy。
文摘It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.
基金funded by the National Natural Science Foundation of China (Grant No. 11975145)
文摘This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this goal,the Krori and Barua arrangement for spherically symmetric components of the line element is incorporated.We explore the field equations by selecting appropriate off-diagonal tetrad fields.Born-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are used.The Born-Infeld gravity was the first modified teleparallel gravity to discuss inflation.We use the linear equation of state pr=ξρto separate the quintessence density.After obtaining the field equations,we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models.We use observational data,such as the mass and radius of the compact star candidates PSRJ 1416-2230,Cen X-3,&4U 1820-30,to ensure the physical plausibility of our findings.
文摘Ground penetrating radar (GPR) surveys have being applied to investigate very near-surface stratification of sedimentary units in coastal plains and to define their depositional conditions. This paper presents, however, low-frequency GPR survey to investigate fault-related depositional systems at greater depths. The Quinta-Cassino area in the Rio Grande do Sul Coastal Plain (RGSCP, Brazil) shows a wide strandplain that is made off by very long, continuous, and linear geomorphic features (beach ridges). This strandplain extends for ~70 km southward. The beach ridges show low-angle truncations against the Quinta escarpment, and also truncations in the strandplain. The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;previous model assumes that no deformational episode occurred in RGSCP. The geophysical and geological surveys carried out in this area showed the existence of listric fault controlling the beach ridges in the escarpments and hanging-wall blocks. The radargrams could distinguish Pleistocene basement unit anticlockwise rotation, thickening of beach ridges radarfacies close to listric normal faults, and horst structures. These deformational features indicate that the extensional zone of a large-scale gravity-driven structure controlled the mechanical subsidence, the Holocene sedimentation and its stratigraphic and geomorphic features in the Quinta-Cassino area to build up an asymmetric delta. The results point to a new approach in dealing with RGSCP Holocene evolution.
基金The National Key R&D Program of China under contract Nos 2022YFC3003800,2020YFC1521700 and 2020YFC1521705the National Natural Science Foundation of China under contract No.41830540+3 种基金the Open Fund of the East China Coastal Field Scientific Observation and Research Station of the Ministry of Natural Resources under contract No.OR-SECCZ2022104the Deep Blue Project of Shanghai Jiao Tong University under contract No.SL2020ZD204the Special Funding Project for the Basic Scientific Research Operation Expenses of the Central Government-Level Research Institutes of Public Interest of China under contract No.SZ2102the Zhejiang Provincial Project under contract No.330000210130313013006。
文摘Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the seafloor has been precisely modeled to date,and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data.In this study,we introduce a pretrained visual geometry group network(VGGNet)method based on deep learning.To apply this method,we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter,which has a larger spatial coverage,based on the former,which is considered the true value and is more accurate.After obtaining the corrected high-precision gravity model,it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation.We choose four data pairs collected from different environments,i.e.,the Southern Ocean,Pacific Ocean,Atlantic Ocean and Caribbean Sea,to evaluate the topographic correction results of the model.The experiments show that the coefficient of determination(R~2)reaches 0.834 among the results of the four experimental groups,signifying a high correlation.The standard deviation and normalized root mean square error are also evaluated,and the accuracy of their performance improved by up to 24.2%compared with similar research done in recent years.The evaluation of the R^(2) values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research.Finally,the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21%within 1%of the total water depths,which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results.
文摘This article describes an extension of the theory of vortices to electromagnetic types with a start point from known fluid systems. From this, properties of gravity-generating objects (particles and black holes) can be derived, which can also describe their possible interior. This also leads to questions about stability, which are then addressed and ultimately lead to considerations of black holes and their possible internal structure. The results fit into the observable areas and can also be directly verified because they were analytically calculated in SI units.
