We perform the manifestly covariant quantization of f(R)gravity in the de Donder gauge condition(or harmonic gauge condition)for general coordinate invariance.We explicitly calculate various equal-time commutation rel...We perform the manifestly covariant quantization of f(R)gravity in the de Donder gauge condition(or harmonic gauge condition)for general coordinate invariance.We explicitly calculate various equal-time commutation relations(ETCRs),in particular the ETCR between the metric and its time derivative,and show that it has a nonvanishing and nontrivial expression,whose situation should be contrasted to the previous result in higher-derivative or quadratic gravity where the ETCR was found to be identically vanishing.We also clarify global symmetries,the physical content of f(R)gravity,and clearly show that this theory is manifestly unitary and has a massive scalar and massless graviton as physical modes.展开更多
Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dand...Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station.展开更多
This study explores asymptotically flat wormhole solutions within the framework of f(R,T)gravity.We analyze f(R,T)expressed as f(R,T)=R+λT+λ_(1)T^(2).A linear equation of state(EoS)is employed for both radial and la...This study explores asymptotically flat wormhole solutions within the framework of f(R,T)gravity.We analyze f(R,T)expressed as f(R,T)=R+λT+λ_(1)T^(2).A linear equation of state(EoS)is employed for both radial and lateral pressures,resulting in a power-law shape function.The investigation encompasses solutions characterized by both negative and positive energy densities.It has been determined that solutions with positive energy density comply with all energy conditions,specifically the null,weak,strong,and dominant energy conditions.Additionally,we identify constraints on the parametersλ,λ_(1),and the parameters associated with the EoS and shape function.展开更多
Dear Editor,As space exploration transitions from short orbital missions to extended stays on the International Space Station(ISS)and,ultimately,interplanetary travel,astronaut health has emerged as a critical focus.I...Dear Editor,As space exploration transitions from short orbital missions to extended stays on the International Space Station(ISS)and,ultimately,interplanetary travel,astronaut health has emerged as a critical focus.In particular,safeguarding cardiovascular function has become an operational imperative.Yet beyond safeguarding those in orbit,the physiological adaptations observed in microgravity offer a compelling lens through which to examine persistent challenges in terrestrial medicine,from orthostatic intolerance in the elderly to deconditioning in critical care survivors.By studying how the human cardiovascular system functions in the absence of gravity.展开更多
Basement structures may influence how ruptures propagate during an earthquake.However,most structural evidence is beneath the thick layer of younger volcanic sediments.In this study,gravity method was applied to disco...Basement structures may influence how ruptures propagate during an earthquake.However,most structural evidence is beneath the thick layer of younger volcanic sediments.In this study,gravity method was applied to discover more features of the basement structure.A land survey of gravity measurement was conducted at 383 stations south of Toba.The observed gravity was then used to generate Complete Bouguer Anomaly and residual-regional anomaly maps.In addition,several edge enhancements based on derivations were applied.All results presented lineations that could be linked to previously recognized active faults and structures.Additionally,the most prominent feature is a large northwest-southeast elongated high anomaly,almost sub-parallel to the Sumatra Fault Zone(SFZ).Since the feature is also located at the continuation of the Medial Sumatra Tectonic Zone(MSTZ),the body might be the hidden part of this major tectonic zone.The occurrence of MSTZ across the SFZ would affect the rupture propagation of earthquake events in the fault segment of the SFZ.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
Since the as-cast microstructure benefits dynamic recrystallization(DRX)nucleation,the present research is focused on the microstructure evolution associated with the dendrites and precipitates during the thermal defo...Since the as-cast microstructure benefits dynamic recrystallization(DRX)nucleation,the present research is focused on the microstructure evolution associated with the dendrites and precipitates during the thermal deformation of an ingot without homogenization treatment aiming at exploring a new efficient strategy of ingot cogging for superalloys.The as-cast samples were deformed at the sub-solvus temperature,and the DRX evolution from dendritic arms(DAs)to inter-dendritic regions(IDRs)was discussed based on the observation of the fishnet-like DRX microstructures and the gradient of DRX grain size at IDRs.The difference in the precipitates at DAs and IDRs played an essential role during the deformation and DRX process,which finally resulted in very different microstructures in the two areas.A selective straininduced grain boundary bulging(SIGBB)mechanism was found to function well and dominate the DRX nucleation at DAs.The grain boundary was able to migrate and bulge to nucleate on the condition that the boundary was located at DAs and had a great difference in dislocation density between its opposite sides at the same time.As for DRX nucleation at IDRs,the particle-stimulated nucleation(PSN)mechanism played a leading role,and the progressive subgrain rotation(PSR)and geometric DRX were two important supplementary mechanisms.The dislocation accumulation around the coarse precipitates at IDR resulted in progressive orientation rotation,which would generate DRX nuclei once the maximum misorientation there was sufficient to form a high-angle boundary with the matrix.The PSR or geometric DRX functioned at the severely elongated IDRs at the later stage of deformation,depending on the thickness of the elongated IDRs.The uniform microstructure was obtained by the deformation without homogenization and the subsequent annealing treatment.The smaller strain,the lower annealing temperature,and the much shorter soaking time requested in the above process lead to a smaller risk of cracking and a lower consumption of energy during the ingot-cogging process.展开更多
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
Comprehensive utilization of phosphogypsum(PG)has attracted much attention,especially for the recovery of rare earth elements(REEs)and gypsum due to the issues of stockpile,environmental pollution,and waste of associa...Comprehensive utilization of phosphogypsum(PG)has attracted much attention,especially for the recovery of rare earth elements(REEs)and gypsum due to the issues of stockpile,environmental pollution,and waste of associated resources.Traditional utilization methods suffered the issues of low REEs leaching efficiency,huge amount of CaSO_(4)saturated wastewater and high recovery cost.To solve these issues,this study investigated the occurrence of REEs in PG and the leaching of REEs.The results show that REEs in PG are in the forms of(1)REEs mineral inclusions,(2)REEs isomorphous substitution of Ca^(2+)in gypsum lattice,(3)dispersed soluble REEs salts.Acid leaching results demonstrate that(1)the dissolution of gypsum matrix is the control factor of REEs leaching;(2)H_(2)SO_(4)is a promising leachant considering the recycle of leachate;(3)the gypsum matrix suffers a recrystallization during the acid leaching and releases the soluble REEs from PG to aqueous solution.For the recovery of the undissolved REEs mineral inclusions,wet sieving concentrated 37.1 wt%of the REEs in a 10.7 wt%mass,increasing REEs content from 309 to 1071 ppm.Finally,a green process combining gravity separation and hydrometallurgy is proposed.This process owns the merits of wastewater free,considerable REEs recovery(about 10%increase compared with traditional processes),excellent gypsum purification(>95 wt%CaSO_(4)·2H_(2)O,with<0.06 wt%of soluble P_(2)O_(5) and<0.015 wt%of soluble F)and reagent saving(about 2/3less reagent consumption than non-cyclical leaching).展开更多
Copper and cobalt were recovered from SICOMINES mining waste rock in the Democratic Republic of Congo.The process mineralogy of the samples was analyzed using scanning electron microscopy and energy dispersive spectro...Copper and cobalt were recovered from SICOMINES mining waste rock in the Democratic Republic of Congo.The process mineralogy of the samples was analyzed using scanning electron microscopy and energy dispersive spectroscopy.The results showed that copper minerals exhibited various forms and uneven particle sizes,while cobalt existed in the form of highly dispersed asbolane,and large amounts of easily slimed gangue minerals were filled in the samples,making it difficult to separate copper and cobalt minerals.The particle size range plays a decisive role in selecting the separation method for the copper−cobalt ore.Gravity separation was suitable for particles ranging from 43 to 246μm,while flotation was more effective for particles below 43μm.After ore grinding and particle size classification,applying a combined gravity separation(shaking table)−flotation method yielded concentrated minerals with a copper recovery of 72.83%and a cobalt recovery of 31.13%.展开更多
Coal gasification fine slag(CGFS)is a solid waste produced in the process of coal gasification.The separation of residue carbon in CGFS is essential for its resource utilization.In this study,the basic physical proper...Coal gasification fine slag(CGFS)is a solid waste produced in the process of coal gasification.The separation of residue carbon in CGFS is essential for its resource utilization.In this study,the basic physical properties of CGFS were analyzed and the effect of physical separation experiments were carried out.The gravity separation results indicated that the coarser particle size fraction achieved a good separation effect.The High-carbon product has a yield of 12.53% with an ash content of 16.84%,and the High-ash product has a yield of 17.85%with an ash content of 98.15% were obtained.Theoretical calculations indicated that the apparent density difference between residue carbon and ash minerals in the water phase environment was the basis for achieving separation.The Rich-ash product was further separated by magnetic separation,and both magnetic field characteristics,water elutriation frequency and grinding time had impacts on the magnetic separation effect.Compared to gravity separation alone,the combined gravity-magnetic separation further enhanced the separation effect of residue carbon and ash minerals.The ash content of the Rich-ash product decreased from 80.56% to 69.52% due to the removal of high-ash Fe oxides,and the yield of combined separation tailings increased from 17.85% to 41.75%.The characterization results obtained through SEM-EDS,VSM,XRD and XRF analysis demonstrated significant differences in saturation magnetization,mineral composition and peak intensity among magnetic separation products,confirming that the feasibility of magnetic separation.The research findings contribute to a better understanding of the separation mechanism and provide a new separation process for efficiently enriching residue carbon from CGFS,also facilitate the step utilization of separation products.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
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
In this paper,we computed the fractal dimension of three survey areas within the central and southern sections of the Tan-Lu fault zone using fractal analysis.Subsequently,simulations were conducted to analyze the gra...In this paper,we computed the fractal dimension of three survey areas within the central and southern sections of the Tan-Lu fault zone using fractal analysis.Subsequently,simulations were conducted to analyze the gravity response under a forward model of equivalent density changes.Additionally,we thoroughly investigated the seismic monitoring capabilities of the gravity network in the central and southern regions of the Tan-Lu fault.Expanding on these analyses.Recent gravity field variations were examined in the mid-southern segment of the Tan-Lu fault zone and its surrounding areas from 2013 to2023.The results indicate that the observation capabilities of the northern network in the study area outperform those of the southern gravity network,with the northern network demonstrating a more evenly distributed coverage.The optimal gravity anomaly recovery effect for the entire study area is achieved at a resolution of 0.5°×0.5°.With an equivalent observable signal in the range of 30×10^(-8)m/s^(2) to 40×10^(-8)m/s^(2),the spatial resolution of the gravity network's field source is estimated to be approximately 55 km.From 2013 to 2023,a significant positive change has been observed in the gravity field within the study area.The Tan-Lu fault zone plays a crucial role in governing the crustal movement in this region,with the dextral strike-slip movement trend of the fault persisting.Small earthquakes occur more frequently in the southern section of the fault zone,while strong earthquakes are less common.The alignment of gravity field changes with the fault strike indicates ongoing activity in the fault zone without any signs of locking.In the central segment of the Tan-Lu fault zone in the Shandong region,there appears to be a weaker correlation between gravity field changes and fault trends.This discrepancy may suggest that the area is locked,resulting in the accumulation of stress and strain.It is imperative to monitor the continuous evolution of the gravity field in this region to gain insights into potential seismic risks.展开更多
On September 5, 2022, an earthquake of magnitude M_(S)6.8 occurred in Luding County, Sichuan Province.This earthquake occurred at the key part of the southeast-clockwise extrusion of material on the eastern margin of ...On September 5, 2022, an earthquake of magnitude M_(S)6.8 occurred in Luding County, Sichuan Province.This earthquake occurred at the key part of the southeast-clockwise extrusion of material on the eastern margin of the Qinghai Plateau, the Y-shaped confluence of the Xianshuihe, Longmenshan and Anninghe fault zones. In this study, the three-dimensional dynamic crustal density changes in the earthquake area are obtained by the typical gravity change data from 2019 to 2022 before the earthquake and gravity inversion by growing bodies. The results indicate that gravity changes presented an obvious fourquadrant and gradient belt distribution in the Luding area before the earthquake. The threedimensional density horizontal slices show that small density changes occurred at the epicenter in the mid-to-upper crust between 2019.9-2020.9 and 2019.9-2021.9. At the same time, the surrounding areas exhibited a positive and negative quadrant distribution. These observations indicate that the source region was likely in a stable locked state, with locking-in shear forces oriented in the NW and NE directions. From 2021.9 to 2022.8, the epicentral region showed negative density changes, indicating that the source region was in the expansion stage, approaching a near-seismic state. The three-dimensional density vertical slices reveal a southeastward migration of positive and negative densities near the epicenter and on the western of the Xianshuihe Fault Zone, indicating that the material is flowing out to the southeast. The observed local negative density changes at the epicenter along the Longmenshan Fault Zone are likely associated with the NE-oriented extensional stress shown by the seismic source mechanism. The above results can provide a basis for interpreting pre-earthquake gravity and density changes,thereby contributing to the advancement of earthquake precursor theory.展开更多
文摘We perform the manifestly covariant quantization of f(R)gravity in the de Donder gauge condition(or harmonic gauge condition)for general coordinate invariance.We explicitly calculate various equal-time commutation relations(ETCRs),in particular the ETCR between the metric and its time derivative,and show that it has a nonvanishing and nontrivial expression,whose situation should be contrasted to the previous result in higher-derivative or quadratic gravity where the ETCR was found to be identically vanishing.We also clarify global symmetries,the physical content of f(R)gravity,and clearly show that this theory is manifestly unitary and has a massive scalar and massless graviton as physical modes.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0711402)the Specialized Research Fund for State Key Laboratories。
文摘Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station.
文摘This study explores asymptotically flat wormhole solutions within the framework of f(R,T)gravity.We analyze f(R,T)expressed as f(R,T)=R+λT+λ_(1)T^(2).A linear equation of state(EoS)is employed for both radial and lateral pressures,resulting in a power-law shape function.The investigation encompasses solutions characterized by both negative and positive energy densities.It has been determined that solutions with positive energy density comply with all energy conditions,specifically the null,weak,strong,and dominant energy conditions.Additionally,we identify constraints on the parametersλ,λ_(1),and the parameters associated with the EoS and shape function.
文摘Dear Editor,As space exploration transitions from short orbital missions to extended stays on the International Space Station(ISS)and,ultimately,interplanetary travel,astronaut health has emerged as a critical focus.In particular,safeguarding cardiovascular function has become an operational imperative.Yet beyond safeguarding those in orbit,the physiological adaptations observed in microgravity offer a compelling lens through which to examine persistent challenges in terrestrial medicine,from orthostatic intolerance in the elderly to deconditioning in critical care survivors.By studying how the human cardiovascular system functions in the absence of gravity.
基金National Research and Innovation Agency(BRIN),Indonesia,with Grant No.373/II/FR/3/2022(Expedition and Exploration Fund)and 676/III/PR.01.December 03,2021(Geological Hazard In-House Program)。
文摘Basement structures may influence how ruptures propagate during an earthquake.However,most structural evidence is beneath the thick layer of younger volcanic sediments.In this study,gravity method was applied to discover more features of the basement structure.A land survey of gravity measurement was conducted at 383 stations south of Toba.The observed gravity was then used to generate Complete Bouguer Anomaly and residual-regional anomaly maps.In addition,several edge enhancements based on derivations were applied.All results presented lineations that could be linked to previously recognized active faults and structures.Additionally,the most prominent feature is a large northwest-southeast elongated high anomaly,almost sub-parallel to the Sumatra Fault Zone(SFZ).Since the feature is also located at the continuation of the Medial Sumatra Tectonic Zone(MSTZ),the body might be the hidden part of this major tectonic zone.The occurrence of MSTZ across the SFZ would affect the rupture propagation of earthquake events in the fault segment of the SFZ.
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 Natural Science Foundation of Shaanxi Province of China(No.2023-JC-QN-0466)the National Natural Science Foundation of China(Nos.52305421 and 52175363)+1 种基金the General Research Fund of Hong Kong(No.15223520)the project No.1-ZE1W from the Hong Kong Polytechnic University.
文摘Since the as-cast microstructure benefits dynamic recrystallization(DRX)nucleation,the present research is focused on the microstructure evolution associated with the dendrites and precipitates during the thermal deformation of an ingot without homogenization treatment aiming at exploring a new efficient strategy of ingot cogging for superalloys.The as-cast samples were deformed at the sub-solvus temperature,and the DRX evolution from dendritic arms(DAs)to inter-dendritic regions(IDRs)was discussed based on the observation of the fishnet-like DRX microstructures and the gradient of DRX grain size at IDRs.The difference in the precipitates at DAs and IDRs played an essential role during the deformation and DRX process,which finally resulted in very different microstructures in the two areas.A selective straininduced grain boundary bulging(SIGBB)mechanism was found to function well and dominate the DRX nucleation at DAs.The grain boundary was able to migrate and bulge to nucleate on the condition that the boundary was located at DAs and had a great difference in dislocation density between its opposite sides at the same time.As for DRX nucleation at IDRs,the particle-stimulated nucleation(PSN)mechanism played a leading role,and the progressive subgrain rotation(PSR)and geometric DRX were two important supplementary mechanisms.The dislocation accumulation around the coarse precipitates at IDR resulted in progressive orientation rotation,which would generate DRX nuclei once the maximum misorientation there was sufficient to form a high-angle boundary with the matrix.The PSR or geometric DRX functioned at the severely elongated IDRs at the later stage of deformation,depending on the thickness of the elongated IDRs.The uniform microstructure was obtained by the deformation without homogenization and the subsequent annealing treatment.The smaller strain,the lower annealing temperature,and the much shorter soaking time requested in the above process lead to a smaller risk of cracking and a lower consumption of energy during the ingot-cogging process.
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Project supported by the National Natural Science Foundation of China(52104354)the National Natural Science Foundation of China(51674036)+1 种基金Joint Fund for Nuclear Technology Innovation Sponsored by the National Natural Science Foundation of Chinathe China National Nuclear Corporation(U2067201)。
文摘Comprehensive utilization of phosphogypsum(PG)has attracted much attention,especially for the recovery of rare earth elements(REEs)and gypsum due to the issues of stockpile,environmental pollution,and waste of associated resources.Traditional utilization methods suffered the issues of low REEs leaching efficiency,huge amount of CaSO_(4)saturated wastewater and high recovery cost.To solve these issues,this study investigated the occurrence of REEs in PG and the leaching of REEs.The results show that REEs in PG are in the forms of(1)REEs mineral inclusions,(2)REEs isomorphous substitution of Ca^(2+)in gypsum lattice,(3)dispersed soluble REEs salts.Acid leaching results demonstrate that(1)the dissolution of gypsum matrix is the control factor of REEs leaching;(2)H_(2)SO_(4)is a promising leachant considering the recycle of leachate;(3)the gypsum matrix suffers a recrystallization during the acid leaching and releases the soluble REEs from PG to aqueous solution.For the recovery of the undissolved REEs mineral inclusions,wet sieving concentrated 37.1 wt%of the REEs in a 10.7 wt%mass,increasing REEs content from 309 to 1071 ppm.Finally,a green process combining gravity separation and hydrometallurgy is proposed.This process owns the merits of wastewater free,considerable REEs recovery(about 10%increase compared with traditional processes),excellent gypsum purification(>95 wt%CaSO_(4)·2H_(2)O,with<0.06 wt%of soluble P_(2)O_(5) and<0.015 wt%of soluble F)and reagent saving(about 2/3less reagent consumption than non-cyclical leaching).
基金National Key Research and Development Program of China(No.2020YFC1909202)Major Science and Technology Program of Yunnan Province,China(No.202202AB080012)for financial support。
文摘Copper and cobalt were recovered from SICOMINES mining waste rock in the Democratic Republic of Congo.The process mineralogy of the samples was analyzed using scanning electron microscopy and energy dispersive spectroscopy.The results showed that copper minerals exhibited various forms and uneven particle sizes,while cobalt existed in the form of highly dispersed asbolane,and large amounts of easily slimed gangue minerals were filled in the samples,making it difficult to separate copper and cobalt minerals.The particle size range plays a decisive role in selecting the separation method for the copper−cobalt ore.Gravity separation was suitable for particles ranging from 43 to 246μm,while flotation was more effective for particles below 43μm.After ore grinding and particle size classification,applying a combined gravity separation(shaking table)−flotation method yielded concentrated minerals with a copper recovery of 72.83%and a cobalt recovery of 31.13%.
基金supported by the National Natural Science Foundation of China(52104262)the Joint Funds of the National Natural Science Foundation of China(U23A20131)the National Key Research and Development Plan(2023YFB4103501,2022YFB4101604).
文摘Coal gasification fine slag(CGFS)is a solid waste produced in the process of coal gasification.The separation of residue carbon in CGFS is essential for its resource utilization.In this study,the basic physical properties of CGFS were analyzed and the effect of physical separation experiments were carried out.The gravity separation results indicated that the coarser particle size fraction achieved a good separation effect.The High-carbon product has a yield of 12.53% with an ash content of 16.84%,and the High-ash product has a yield of 17.85%with an ash content of 98.15% were obtained.Theoretical calculations indicated that the apparent density difference between residue carbon and ash minerals in the water phase environment was the basis for achieving separation.The Rich-ash product was further separated by magnetic separation,and both magnetic field characteristics,water elutriation frequency and grinding time had impacts on the magnetic separation effect.Compared to gravity separation alone,the combined gravity-magnetic separation further enhanced the separation effect of residue carbon and ash minerals.The ash content of the Rich-ash product decreased from 80.56% to 69.52% due to the removal of high-ash Fe oxides,and the yield of combined separation tailings increased from 17.85% to 41.75%.The characterization results obtained through SEM-EDS,VSM,XRD and XRF analysis demonstrated significant differences in saturation magnetization,mineral composition and peak intensity among magnetic separation products,confirming that the feasibility of magnetic separation.The research findings contribute to a better understanding of the separation mechanism and provide a new separation process for efficiently enriching residue carbon from CGFS,also facilitate the step utilization of separation products.
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supported by the Three-pronged Project on Earthquake Monitoring,Forecasting and Scientific Research of the China Earthquake Administration(No.3JH-202402026)The Open Fund of Wuhan,Gravitation and Solid Earth Tides,National Observation and Research Station(WHYWZ202209)+1 种基金The Joint Open Fund of Mengcheng National Geophysical Observatory(No.MENGO-202210 and MENGO-202211)The Science for Earthquake Resilience,China Earthquake Administration(No.XH22002YA)。
文摘In this paper,we computed the fractal dimension of three survey areas within the central and southern sections of the Tan-Lu fault zone using fractal analysis.Subsequently,simulations were conducted to analyze the gravity response under a forward model of equivalent density changes.Additionally,we thoroughly investigated the seismic monitoring capabilities of the gravity network in the central and southern regions of the Tan-Lu fault.Expanding on these analyses.Recent gravity field variations were examined in the mid-southern segment of the Tan-Lu fault zone and its surrounding areas from 2013 to2023.The results indicate that the observation capabilities of the northern network in the study area outperform those of the southern gravity network,with the northern network demonstrating a more evenly distributed coverage.The optimal gravity anomaly recovery effect for the entire study area is achieved at a resolution of 0.5°×0.5°.With an equivalent observable signal in the range of 30×10^(-8)m/s^(2) to 40×10^(-8)m/s^(2),the spatial resolution of the gravity network's field source is estimated to be approximately 55 km.From 2013 to 2023,a significant positive change has been observed in the gravity field within the study area.The Tan-Lu fault zone plays a crucial role in governing the crustal movement in this region,with the dextral strike-slip movement trend of the fault persisting.Small earthquakes occur more frequently in the southern section of the fault zone,while strong earthquakes are less common.The alignment of gravity field changes with the fault strike indicates ongoing activity in the fault zone without any signs of locking.In the central segment of the Tan-Lu fault zone in the Shandong region,there appears to be a weaker correlation between gravity field changes and fault trends.This discrepancy may suggest that the area is locked,resulting in the accumulation of stress and strain.It is imperative to monitor the continuous evolution of the gravity field in this region to gain insights into potential seismic risks.
基金the National Natural Science Foundation of China(Grant No.42374105,42204089,42174104)Scientific Research Fund of Institute of Seismology,China Earthquake Administration(Grant No.IS202326341,IS202336350).
文摘On September 5, 2022, an earthquake of magnitude M_(S)6.8 occurred in Luding County, Sichuan Province.This earthquake occurred at the key part of the southeast-clockwise extrusion of material on the eastern margin of the Qinghai Plateau, the Y-shaped confluence of the Xianshuihe, Longmenshan and Anninghe fault zones. In this study, the three-dimensional dynamic crustal density changes in the earthquake area are obtained by the typical gravity change data from 2019 to 2022 before the earthquake and gravity inversion by growing bodies. The results indicate that gravity changes presented an obvious fourquadrant and gradient belt distribution in the Luding area before the earthquake. The threedimensional density horizontal slices show that small density changes occurred at the epicenter in the mid-to-upper crust between 2019.9-2020.9 and 2019.9-2021.9. At the same time, the surrounding areas exhibited a positive and negative quadrant distribution. These observations indicate that the source region was likely in a stable locked state, with locking-in shear forces oriented in the NW and NE directions. From 2021.9 to 2022.8, the epicentral region showed negative density changes, indicating that the source region was in the expansion stage, approaching a near-seismic state. The three-dimensional density vertical slices reveal a southeastward migration of positive and negative densities near the epicenter and on the western of the Xianshuihe Fault Zone, indicating that the material is flowing out to the southeast. The observed local negative density changes at the epicenter along the Longmenshan Fault Zone are likely associated with the NE-oriented extensional stress shown by the seismic source mechanism. The above results can provide a basis for interpreting pre-earthquake gravity and density changes,thereby contributing to the advancement of earthquake precursor theory.
