This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,th...This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,the intercritical,fine-grained,and coarsegrained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure,precipitation,and mechanical properties.At a heat input of 30 kJ·cm^(−1),Ni(Al,Mn)nanoparticles dissolve in the intercritical heat-affected zone,followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling,thereby retaining high strength but reducing impact toughness to(142±10)J(compared to(205±8)J of the base metal).The fine-grained heat-affected zone,under the same heat input,exhibits a refined ferritic-bainite matrix with a few fine Ni(Al,Mn)and slightly coarsened Cu particles,thus enhancing plastic deformation capacity and resulting in superior impact toughness of(196±7)J.Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone,re-precipitated nanoparticles provide effective strengthening effect,compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of(186±6)J.The toughening mechanism is primarily attributed to the synergistic actions of the matrix,precipitates,and deformation twins.These findings provide mechanistic and quantitative insights for developing processing-microstructure-property relationships in different welding heat-affected zones,and this framework can be further utilized to optimize welding parameters for tailored applications.展开更多
The Guanxian-Anxian fault zone in the Longmen Shan,Sichuan,China,exhibits long-term creep-slip but ruptured during the 2008 Wenchuan earthquake,challenging the view that creeping faults rarely generate strong earthqua...The Guanxian-Anxian fault zone in the Longmen Shan,Sichuan,China,exhibits long-term creep-slip but ruptured during the 2008 Wenchuan earthquake,challenging the view that creeping faults rarely generate strong earthquakes.To investigate the transition from creep-slip to stick-slip,we analyzed fault rocks from the WFSD-3,using microstructural observations,XRD,μXRF,Raman spectroscopy,and quartz grain size statistics.Fault rocks show intense foliation,pressure-solution structures,and abundant clay minerals,reflecting long-term aseismic creep.At the interface between black and gray fault gouges at~1249.98 m,microstructures indicate stick-slip behavior,including truncated grains,angular fragments,and finer grain sizes.Here,clay content drops sharply while strong minerals(quartz,feldspar,calcite,dolomite)increase.Elemental mapping shows Al and K enriched in black gouge,whereas Ca and Si in gray gouge;Raman spectroscopy indicates possible graphitization;the finest quartz grains occur in black gouge.These features mark co-seismic principal slip zone of the Wenchuan earthquake.We propose that fluid-driven transformation of strong minerals into clays facilitates creep-slip,whereas localized precipitation of strong minerals strengthens the fault,causing stress accumulation and controlling the creep-slip to stick-slip transition.This mechanism has implications for reassessing seismic hazards of creeping faults.展开更多
Nereididae is a prolific annelid family widely distributed in the world oceans,especially in the Indo-Pacific Convergence Zone(IPCZ).However,its biogeographic pattern remains unexplored in IPCZ.To contribute to the un...Nereididae is a prolific annelid family widely distributed in the world oceans,especially in the Indo-Pacific Convergence Zone(IPCZ).However,its biogeographic pattern remains unexplored in IPCZ.To contribute to the understanding of biodiversity and biogeography of Nereididae in the IPCZ,we integrated historical data of species distributions with those of model-predicted ones to determine the biogeographic patterns of nereid species,from which we projected to its future distribution patterns for 2090-2100 under different climate scenarios(SSP1-1.9 and SSP5-8.5).Functional diversity within IPCZ was assessed using functional richness,functional evenness,and functional disparity.Divergence times within Nereididae were estimated using three DNA marker genes(COI,16S,and 18S rRNA),and a time tree was constructed based on a strict molecular clock model.The IPCZ was established as a key Nereididae biodiversity hotspot through distribution modelling of 256 species(44 genera),and temperature emerging as the predominant climatic driver of species distribution patterns.The distribution of species and functional diversity is notable for its non-centralized pattern.We projected that by the end of the century,areas of medium-to-high species richness will expand significantly under the low-emission SSP1-1.9 climate scenario.However,under the high-emission SSP5-8.5 scenario,the suitability of these regions significantly declines,posing an increasingly severe threat to biodiversity.In addition,by molecular clock analysis,we revealed that the evolutionary divergence of extant nereidid species occurred mainly in the Cretaceous and Jurassic,suggesting that paleogeographical and environmental events,such as oceanic anoxic events,might have played a pivotal role in shaping the evolutionary trajectory and ecological adaptations of marine annelids.These findings highlight the importance of considering both current biodiversity patterns and historical contexts in conservation planning,and provided insights into the potential factors on the biogeographic distribution and evolutionary processes of Nereididae.展开更多
Automatic identificationof discontinuities is a key focus in rock slope research.Conventional methods typically target small areas,which limits efficiencyand applicability for complex discontinuities in large-scale ro...Automatic identificationof discontinuities is a key focus in rock slope research.Conventional methods typically target small areas,which limits efficiencyand applicability for complex discontinuities in large-scale rock slopes.This study uses multi-angle unmanned aerial vehicle(UAV)nap-of-the-object photogrammetry to construct a high-definitionthree-dimensional(3D)point cloud model of the slope.The edge-firstconnection algorithm identifiesall edge points of discontinuities in the point cloud and completes recognition through simple connection analysis.This method avoids the complex calculations required for sequentially identifying discontinuity edges in conventional methods and achieves significantacceleration through algorithm optimization and parallel computation support.Based on this algorithm,the RockDiscontinuity Identification(RD ID)software is developed and applied to identify numerous highly disordered discontinuities on the Xulong slope in the Jinsha River suture zone.Processing tens of millions of point clouds within approximately 2 h demonstrates exceptional computational efficiency.The automatic algorithm accurately identifiesnearly 80%of planar discontinuities,with orientations and trace lengths closely matching manual results,highlighting its potential for large-scale rock outcrop applications.Comparisons with region growing algorithms further emphasize its effectiveness and accuracy.However,the algorithm struggles to identify linear discontinuities,which are a major source of error.Additionally,high roughness and smooth edges of discontinuities affect recognition accuracy,indicating areas for further improvement.展开更多
Systematically analyzing the impact mechanisms of policy on Land Use Conflict(LUC)is crucial for constructing effective conflict mitigation strategies.However,previous research on how policy influences LUC remains rel...Systematically analyzing the impact mechanisms of policy on Land Use Conflict(LUC)is crucial for constructing effective conflict mitigation strategies.However,previous research on how policy influences LUC remains relatively limited.Focusing on the indirect driving role of policy on LUC,this study proposed County Development Level(CDL)under Major Function Oriented Zone Planning(MFOZP)guidance as an intermediary variable,bridging the implicit influence of MFOZP and the explicit changes in LUC.Using the Beijing-Tianjin-Hebei(BTH)region in China as a case study,we analyzed the spatio-temporal evolution characteristics of LUC and CDL for the periods 2000-2010 and 2010-2020,before and after MFOZP implementation.Panel models and Geographically Weighted Regression(GWR)were employed to explore the mechanism by which CDL influences LUC under MFOZP guidance.The results show that:1)MFOZP implementation effectively alleviates land use pressure from regional development,with LUC continuously declining at a rate of 2.41%,while CDL exhibits slight growth(3.84%),during 2010-2020.2)Under MFOZP guidance,CDL reduces pressure on Land Use Structure Conflict(LUSC)and Land Use Process Conflict(LUPC),enhances its inhibitory effect on Land Use Function Conflict(LUFC),and significantly contributes to LUC coordination,with notable spatial heterogeneity.3)The coupling relationship between CDL and LUC has improved post-implementation.Based on this,tailored LUC coordination strategies are proposed for different functional zones.This study confirms the effectiveness of MFOZP in coordinating LUC and provides a scientific reference for LUC research under policy frameworks and the governance of LUC in the BTH region.展开更多
In this paper,a coupled thermo-hydro-mechanical(THM)simulation in a faulted deformable porous medium is presented.This model involves solving the mass conservation,linear momentum balance,and energy balance equations ...In this paper,a coupled thermo-hydro-mechanical(THM)simulation in a faulted deformable porous medium is presented.This model involves solving the mass conservation,linear momentum balance,and energy balance equations which are derived from the Biot’s consolidation theory.Fluid pore pressure,solid displacement,and temperature are chosen as initial variables in these equations,and the finite element method in combination with the interface element is used for spatial discretization of continuous and discontinuities(fault)parts of the medium to solve the equations.The main purpose of this study is providing precise formulations,applicability,and ability of the triple-node zero-thickness interface element in THM modeling of faults.It should be noted that the system of equations is solved using a computer code written in Matlab program.In order to verify the developed method,simulations of index problems such as Mandel’s problem,and coupled modeling of a faulted porous medium and a faulted aquifer are presented.The modeling results obtained from the developed method show a very good agreement with those by other modeling methods,which indicates its accuracy.展开更多
Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investiga...Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.展开更多
Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide i...Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.展开更多
The Litang fault zone is an important seismogenic structure along the southeastern margin of the Tibetan Plateau.It caused the M71/4 earthquake in Litang in 1948 AD.The fault zone intersects the Sichuan-Xizang transpo...The Litang fault zone is an important seismogenic structure along the southeastern margin of the Tibetan Plateau.It caused the M71/4 earthquake in Litang in 1948 AD.The fault zone intersects the Sichuan-Xizang transportation corridor and poses a serious risk to its safe operation.This study,utilizing high-resolution remote sensing interpretation,field geological verification,UAV photogrammetry,UAV LiDAR,paleoearthquake trench excavation,and AMS^(14)C and OSL dating methods,reveals the geometric structure,slip rates,paleoearthquake sequence,and earthquake rupture segmentation of the Litang fault zone;analyzes the rupture distribution range of the 1729 AD Litang earthquake and estimates its magnitude.The study indicates that the Litang fault zone is a relatively immature strike-slip fault,which has developed as a new active fault zone within the Northwestern Sichuan sub-block during the southeastward material migration of the southeastern margin of the Tibetan Plateau.This reflects a transformation in the deformation model of the Northwestern Sichuan sub-block crust from the‘Rigid Block’model to the‘Continuous Deformation’model.展开更多
The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and...The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and the internal component of a landslide.Therefore,considering the strength changes of the sliding zone with seepage effects,they correspond with the actual hydrogeological circumstances.To investigate the shear behavior of sliding zone soil under various seepage pressures,24 samples were conducted by a self-developed apparatus to observe the shear strength and measure the permeability coefficients at different deformation stages.After seepage-shear tests,the composition of clay minerals and microscopic structure on the shear surface were analyzed through X-ray and scanning electron microscope(SEM)to understand the coupling effects of seepage on strength.The results revealed that the sliding zone soil exhibited strain-hardening without seepage pressure.However,the introduction of seepage caused a significant reduction in shear strength,resulting in strain-softening characterized by a three-stage process.Long-term seepage action softened clay particles and transported broken particles into effective seepage channels,causing continuous damage to the interior structure and reducing the permeability coefficient.Increased seepage pressure decreased the peak strength by disrupting occlusal and frictional forces between sliding zone soil particles,which carried away more clay particles,contributing to an overhead structure in the soil that raised the permeability coefficient and decreased residual strength.The internal friction angle was less sensitive to variations in seepage pressure than cohesion.展开更多
Nitrate(NO_(3)^(-))accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO_(3)^(-)content in intensive agricultural regions.Agricultural land-use change(ALUC),typically...Nitrate(NO_(3)^(-))accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO_(3)^(-)content in intensive agricultural regions.Agricultural land-use change(ALUC),typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing factor.This study evaluated the changes in NO_(3)^(-)accumulation and transport in the deep vadose zone(DVZ,below the root zone),and the groundwater NO_(3)^(-)content associated with ALUC from grain to vegetable fields in the North China Plain(NCP).The ALUC from grain to vegetable resulted in nitrate–nitrogen(NO_(3)^(-)-N)accumulation in DVZ increased by 235.5 kg ha^(-1)m^(-1)(163.2%)in the piedmont plain and 224.9 kg ha^(-1)m^(-1)(102.7%)in the central plain,respectively.This change accelerated downward transport velocity in the DVZ(from 0.81±0.47 to 0.89±0.55 m yr^(-1)in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr^(-1)in the central plain)and increased NO_(3)^(-)leaching fluxes.High transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont plain.The impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.展开更多
The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthqu...The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthquake risk zones. In this study, we leveraged a dense seismic array to investigate the high-resolution shallow crust shear wave velocity(Vs) structure beneath the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone, one of the most complex parts of the eastern boundary of the South Chuan–Dian Block. We analyzed the distribution of microseismic events detected between November 2022 and February 2023 based on the fine-scale Vs model obtained. The microseismicity in the study region was clustered into three groups, all spatially related to major faults in this region. These microseismic events indicate near-vertical fault planes, consistent with the fault geometry revealed by other researchers.Moreover, these microseismic events are influenced by the impoundment of the downstream Baihetan Reservoir and the complex tectonic stress near the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone. The depths of these microseismic events are shallower in the junction zone, whereas moving south along the Xiaojiang Fault Zone, the microseismic events become deeper.Additionally, we compared our fine-scale local Vs model with velocity models obtained by other researchers and found that our model offers greater detail in characterizing subsurface heterogeneity while demonstrating improved reliability in delineating fault systems.展开更多
This work focuses on the influence of Al content on the precipitation of nanoprecipitates,growth of prior austenite grains(PAGs),and impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two exp...This work focuses on the influence of Al content on the precipitation of nanoprecipitates,growth of prior austenite grains(PAGs),and impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two experimental shipbuilding steels after being subjected to high-heat input welding at 400 kJ·cm^(-1).The base metals (BMs) of both steels contained three types of precipitates Type Ⅰ:cubic (Ti,Nb)(C,N),Type Ⅱ:precipitate with cubic (Ti,Nb)(C,N) core and Nb-rich cap,and Type Ⅲ:ellipsoidal Nb-rich precipitate.In the BM of 60Al and 160Al steels,the number densities of the precipitates were 11.37×10^(5) and 13.88×10^(5) mm^(-2),respectively The 60Al and 160Al steel contained 38.12% and 6.39% Type Ⅲ precipitates,respectively.The difference in the content of Type Ⅲ precipitates in the 60Al steel reduced the pinning effect at the elevated temperature of the CGHAZ,which facilitated the growth of PAGs The average PAG sizes in the CGHAZ of the 60Al and 160Al steels were 189.73 and 174.7μm,respectively.In the 60Al steel,the low lattice mismatch among Cu_(2)S,TiN,and γ-Al_(2)O_(3)facilitated the precipitation of Cu_(2)S and TiN onto γ-Al_(2)O_(3)during welding,which decreased the number density of independently precipitated (Ti,Nb)(C,N) particles but increased that of γ-Al_(2)O_(3)–Ti N–Cu_(2)S particles.Thus abnormally large PAGs formed in the CGHAZ of the 60Al steel,and they reached a maximum size of 1 mm.These PAGs greatly reduced the microstructural homogeneity and consequently decreased the impact toughness from 134 (0.016wt%Al) to 54 J (0.006wt%Al)at-40℃.展开更多
The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structur...The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structure in the upper crust and seismogenic tectonics in the Hefei segment of this fault, we collected phase velocity dispersion data of fundamental mode Rayleigh waves from ambient noise cross-correlation functions of ~400 temporal seismographs in an area of approximately 80 × 70 km along the fault zone. The period band of the dispersion data was ~0.5–10 s. We inverted for the upper crustal three-dimensional(3-D) shear velocity model with azimuthal anisotropy from the surface to 10 km depth by using a 3-D direct azimuthal anisotropy inversion method. The inversion result shows the spatial distribution characteristics of the tectonic units in the upper crust. Additionally, the deformation of the Tan-Lu Fault Zone and its conjugated fault systems could be inferred from the anisotropy model. In particular, the faults that have remained active from the early and middle Pleistocene control the anisotropic characteristics of the upper crustal structure in this area. The direction of fast axes near the fault zone area in the upper crust is consistent with the strike of the faults, whereas for the region far away from the fault zone, the direction of fast axes is consistent with the direction of the regional principal stress caused by plate movement. Combined with the azimuthal anisotropy models in the deep crust and uppermost mantle from the surface wave and Pn wave, the different anisotropic patterns caused by the Tan-Lu Fault Zone and its conjugated fault system nearby are shown in the upper and lower crust. Furthermore,by using the double-difference method, we relocated the Lujiang earthquake series, which contained 32 earthquakes with a depth shallower than 10 km. Both the Vs model and earthquake relocation results indicate that earthquakes mostly occurred in the vicinity of structural boundaries with fractured media, with high-level development of cracks and small-scale faults jammed between more rigid areas.展开更多
High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.Hi...High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9.展开更多
As the mine depth around the world increases,the temperature of the surrounding rock of the mining workface increases significantly.To control the heat hazards,the hot water in the mining floor is developed during min...As the mine depth around the world increases,the temperature of the surrounding rock of the mining workface increases significantly.To control the heat hazards,the hot water in the mining floor is developed during mining to decrease the min-ing workface temperature while also developing geothermal energy.This method is called the co-exploitation of mine and geothermal energy(CMGE).The geothermal development may precipitate the large-scale failure of the nearby fault zone during the mining process.However,the evolution of shear slide and shear failure of fault under geothermal production/rein-jection during mining is missing.Therefore,a fully-coupled hydraulic mechanism(HM)double-medium model for CMGE was developed based on the measured data of the Chensilou mine.A comparative analysis of the mechanical response of fault between CMGE and single mining was conducted.The disturbance of geothermal production pressure and reinjection pressure under mining on fault stability were respectively expounded.The results indicate that:(1)The disturbance of geo-thermal reinjection amplifies the disturbance of mining on fault stability.The amplified effect resulted in a normal stress drop of the fault,further leading to a substantial increase in shear slide distance,failure area,and cumulative seismic moment of fault compared with the single mining process.(2)As the distance of reinjection well to the fault decreases,the fault failure intensity increases.Setting the production well within the fault is advantageous for controlling fault stability under CMGE.(3)The essence of the combined disturbance of CMGE on the nearby fault is the overlay of tensile stress disturbance on the fault rock mass of the mining and geothermal reinjection.Though the geothermal reinjection causes a minor normal stress drop of fault,it can result in a more serious fault failure under CMGE.This paper supplies a significant gap in understanding thenearby faults failure under CMGE.展开更多
The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velo...The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.展开更多
Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. Thi...Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. This is done by examining the acetabular placement in instances of hip dislocation after total hip arthroplasty (THA). Methodology: The authors searched 2653 patient records from 2015 to 2022 looking for patients who had total hip arthroplasty at our facility. For the analysis, 23 patients were culled from 64 individuals who exhibited post-THA dislocations, employing a stringent exclusion criterion, and the resultant acetabular angulation and anteversion were quantified utilizing PEEKMED software (Peek Health S.A., Portugal) upon radiographic evidence. Results: Within the operational timeframe, from the cohort of 2653 subjects, 64 presented with at least a singular incident of displacement. Post-exclusion criterion enforcement, 23 patients were eligible for inclusion. Of these, 10 patients conformed to the safe zone demarcated by Lewinnek for both inclination and anteversion angles, while 13 exhibited deviations from the prescribed anteversion and/or inclination benchmarks. Conclusion: Analysis of the 23 patients reveals that 13 did not confirm to be in the safe zone parameters for anteversion and/or inclination, whereas 10 were within the safe zone as per Lewinnek’s guidelines. This investigative review, corroborated by extant literature, suggests that the isolated consideration of the Lewinnek safe zone does not suffice as a solitary protective factor. It further posits that additional variables are equally critical as acetabular positioning and mandate individual assessment.展开更多
As one of the typical deposits in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province,the Daliangzi Pb-Zn deposit has a close genetic relationship with the structural system of the black/fracture zone formed under ...As one of the typical deposits in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province,the Daliangzi Pb-Zn deposit has a close genetic relationship with the structural system of the black/fracture zone formed under the action of the NWW-approximately EW strike-slip structures in the metallogenic province.The R1 black/fracture zone has a close relationship with ore forming;however,the mechanism of the rock-and ore-controlling action of the structural system remains unclear.Based on a detailed analysis of the tectonite-mineralized alteration lithofacies of the R1 black/fracture zone,the tectonite-mineralized alteration lithofacies zones can be divided into four types in succession outward from the Pb-Zn mineralization center(F_(5),F_(100),and other faults),i.e.,(1)the brecciated and stockwork-like Pb-Zn mineralization-complex breccia facies zone;(2)the stockwork-like Pb-Zn mineralization-simple breccia and cataclasite facies zone;(3)the veined pyrite-sulfide-dolomitic cataclasite facies zone;(4)the fine-veined calcite-black carbonized dolomite facies zone.With the evolution of the ore-forming fluid,the homogenization temperature decreases from Zone 1 to Zone 4;the salinity increases from Zone 1 to Zone 2 and then it decreases from Zones 3 and 4.The fluid density shows little change overall.The contents of Zn,Pb,Cu,Ga,Ge,Cd,Ag,and other metallogenic elements,Zn/Pb ratio,and CaO/MgO mole ratio decrease gradually from Zone 1 to Zone 4,and the REE fractionation,calcilization,silicification,and pyritization enhance gradually from Zone 1 to Zone 4.This series of changes is the product of diapirism(cryptoexplosion)of strike-slip structures and the black/fracture zone,among which the second-order structures derived from NWW-approximately EW-striking dextral shear-tension faults F_(1)and F_(15)control the brecciated and stockwork-like Pb-Zn mineralized complex breccia facies zones and the stockwork-like Pb-Zn mineralized simple breccia and cataclasite facies zones.Therefore,this paper establishes the zoning mode of tectonite-mineralized alteration lithofacies of the black/fracture zone and proposes that Zones 1 and 2 provide important prospecting criteria.展开更多
基金supported by the National Natural Science Foundation of China(No.U2330110)Youth Science Foundation Project(Category A)of Liaoning Province,China(No.2025JH6/101100006).
文摘This study investigates the microstructure and co-precipitation behavior of multicomponent(Ni(Al,Mn)and Cu)nanoparticles in the weld heat-affected zones of high-strength low-carbon steel.Through thermal simulations,the intercritical,fine-grained,and coarsegrained heat-affected zones were systematically characterized to elucidate the interplay between the microstructure,precipitation,and mechanical properties.At a heat input of 30 kJ·cm^(−1),Ni(Al,Mn)nanoparticles dissolve in the intercritical heat-affected zone,followed by dense reprecipitation coupled with significant coarsening of Cu particles during cooling,thereby retaining high strength but reducing impact toughness to(142±10)J(compared to(205±8)J of the base metal).The fine-grained heat-affected zone,under the same heat input,exhibits a refined ferritic-bainite matrix with a few fine Ni(Al,Mn)and slightly coarsened Cu particles,thus enhancing plastic deformation capacity and resulting in superior impact toughness of(196±7)J.Despite complete dissolution of original precipitates at peak temperatures in the coarse-grained heat-affected zone,re-precipitated nanoparticles provide effective strengthening effect,compensating for grain coarsening and dislocation recovery and resulting in an impressive impact toughness of(186±6)J.The toughening mechanism is primarily attributed to the synergistic actions of the matrix,precipitates,and deformation twins.These findings provide mechanistic and quantitative insights for developing processing-microstructure-property relationships in different welding heat-affected zones,and this framework can be further utilized to optimize welding parameters for tailored applications.
基金supported by the National Natural Science Foundation of China(42230312,42272270,42172262,42372266)the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(2024ZD1000500)the China Geological Survey Project(DD20240041).
文摘The Guanxian-Anxian fault zone in the Longmen Shan,Sichuan,China,exhibits long-term creep-slip but ruptured during the 2008 Wenchuan earthquake,challenging the view that creeping faults rarely generate strong earthquakes.To investigate the transition from creep-slip to stick-slip,we analyzed fault rocks from the WFSD-3,using microstructural observations,XRD,μXRF,Raman spectroscopy,and quartz grain size statistics.Fault rocks show intense foliation,pressure-solution structures,and abundant clay minerals,reflecting long-term aseismic creep.At the interface between black and gray fault gouges at~1249.98 m,microstructures indicate stick-slip behavior,including truncated grains,angular fragments,and finer grain sizes.Here,clay content drops sharply while strong minerals(quartz,feldspar,calcite,dolomite)increase.Elemental mapping shows Al and K enriched in black gouge,whereas Ca and Si in gray gouge;Raman spectroscopy indicates possible graphitization;the finest quartz grains occur in black gouge.These features mark co-seismic principal slip zone of the Wenchuan earthquake.We propose that fluid-driven transformation of strong minerals into clays facilitates creep-slip,whereas localized precipitation of strong minerals strengthens the fault,causing stress accumulation and controlling the creep-slip to stick-slip transition.This mechanism has implications for reassessing seismic hazards of creeping faults.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the National Natural Science Foundation of China(No.42376092)the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(No.2022QNLM030004)。
文摘Nereididae is a prolific annelid family widely distributed in the world oceans,especially in the Indo-Pacific Convergence Zone(IPCZ).However,its biogeographic pattern remains unexplored in IPCZ.To contribute to the understanding of biodiversity and biogeography of Nereididae in the IPCZ,we integrated historical data of species distributions with those of model-predicted ones to determine the biogeographic patterns of nereid species,from which we projected to its future distribution patterns for 2090-2100 under different climate scenarios(SSP1-1.9 and SSP5-8.5).Functional diversity within IPCZ was assessed using functional richness,functional evenness,and functional disparity.Divergence times within Nereididae were estimated using three DNA marker genes(COI,16S,and 18S rRNA),and a time tree was constructed based on a strict molecular clock model.The IPCZ was established as a key Nereididae biodiversity hotspot through distribution modelling of 256 species(44 genera),and temperature emerging as the predominant climatic driver of species distribution patterns.The distribution of species and functional diversity is notable for its non-centralized pattern.We projected that by the end of the century,areas of medium-to-high species richness will expand significantly under the low-emission SSP1-1.9 climate scenario.However,under the high-emission SSP5-8.5 scenario,the suitability of these regions significantly declines,posing an increasingly severe threat to biodiversity.In addition,by molecular clock analysis,we revealed that the evolutionary divergence of extant nereidid species occurred mainly in the Cretaceous and Jurassic,suggesting that paleogeographical and environmental events,such as oceanic anoxic events,might have played a pivotal role in shaping the evolutionary trajectory and ecological adaptations of marine annelids.These findings highlight the importance of considering both current biodiversity patterns and historical contexts in conservation planning,and provided insights into the potential factors on the biogeographic distribution and evolutionary processes of Nereididae.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3080200)the China Postdoctoral Science Foundation(Grant No.2023M731264)the Science and Technology Development Plan Project of Jilin Province,China(Grant No.20250602007RC).
文摘Automatic identificationof discontinuities is a key focus in rock slope research.Conventional methods typically target small areas,which limits efficiencyand applicability for complex discontinuities in large-scale rock slopes.This study uses multi-angle unmanned aerial vehicle(UAV)nap-of-the-object photogrammetry to construct a high-definitionthree-dimensional(3D)point cloud model of the slope.The edge-firstconnection algorithm identifiesall edge points of discontinuities in the point cloud and completes recognition through simple connection analysis.This method avoids the complex calculations required for sequentially identifying discontinuity edges in conventional methods and achieves significantacceleration through algorithm optimization and parallel computation support.Based on this algorithm,the RockDiscontinuity Identification(RD ID)software is developed and applied to identify numerous highly disordered discontinuities on the Xulong slope in the Jinsha River suture zone.Processing tens of millions of point clouds within approximately 2 h demonstrates exceptional computational efficiency.The automatic algorithm accurately identifiesnearly 80%of planar discontinuities,with orientations and trace lengths closely matching manual results,highlighting its potential for large-scale rock outcrop applications.Comparisons with region growing algorithms further emphasize its effectiveness and accuracy.However,the algorithm struggles to identify linear discontinuities,which are a major source of error.Additionally,high roughness and smooth edges of discontinuities affect recognition accuracy,indicating areas for further improvement.
基金Under the auspices of the National Key Research and Development Program of China(No.2018YFD1100803)the Fundamental Research Fund for the Central Universities(Ph.D.Top Innovative Talents Fund of CUMTB)(No.BBJ2024029)。
文摘Systematically analyzing the impact mechanisms of policy on Land Use Conflict(LUC)is crucial for constructing effective conflict mitigation strategies.However,previous research on how policy influences LUC remains relatively limited.Focusing on the indirect driving role of policy on LUC,this study proposed County Development Level(CDL)under Major Function Oriented Zone Planning(MFOZP)guidance as an intermediary variable,bridging the implicit influence of MFOZP and the explicit changes in LUC.Using the Beijing-Tianjin-Hebei(BTH)region in China as a case study,we analyzed the spatio-temporal evolution characteristics of LUC and CDL for the periods 2000-2010 and 2010-2020,before and after MFOZP implementation.Panel models and Geographically Weighted Regression(GWR)were employed to explore the mechanism by which CDL influences LUC under MFOZP guidance.The results show that:1)MFOZP implementation effectively alleviates land use pressure from regional development,with LUC continuously declining at a rate of 2.41%,while CDL exhibits slight growth(3.84%),during 2010-2020.2)Under MFOZP guidance,CDL reduces pressure on Land Use Structure Conflict(LUSC)and Land Use Process Conflict(LUPC),enhances its inhibitory effect on Land Use Function Conflict(LUFC),and significantly contributes to LUC coordination,with notable spatial heterogeneity.3)The coupling relationship between CDL and LUC has improved post-implementation.Based on this,tailored LUC coordination strategies are proposed for different functional zones.This study confirms the effectiveness of MFOZP in coordinating LUC and provides a scientific reference for LUC research under policy frameworks and the governance of LUC in the BTH region.
文摘In this paper,a coupled thermo-hydro-mechanical(THM)simulation in a faulted deformable porous medium is presented.This model involves solving the mass conservation,linear momentum balance,and energy balance equations which are derived from the Biot’s consolidation theory.Fluid pore pressure,solid displacement,and temperature are chosen as initial variables in these equations,and the finite element method in combination with the interface element is used for spatial discretization of continuous and discontinuities(fault)parts of the medium to solve the equations.The main purpose of this study is providing precise formulations,applicability,and ability of the triple-node zero-thickness interface element in THM modeling of faults.It should be noted that the system of equations is solved using a computer code written in Matlab program.In order to verify the developed method,simulations of index problems such as Mandel’s problem,and coupled modeling of a faulted porous medium and a faulted aquifer are presented.The modeling results obtained from the developed method show a very good agreement with those by other modeling methods,which indicates its accuracy.
基金supported by the Fundamental Research Funds of the Institute of Geomechanics(DZLXJK202401)the National Natural Science Foundation of China(42177172,U2244226,42172255)+1 种基金the China Geological Survey Project(DD20230538)Deep Earth Probe and Mineral Resources ExplorationNational Science and Technology Major Project(2024ZD1000500)。
文摘Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.
基金supported by the National Key R&D Program of China(No.2021YFA1501002)Thousand Talents Program for Distinguished Young Scholars.X.Li thanks the National Natural Science Foundation of China(No.22309021).
文摘Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.
基金supported by the National Natural Science Foundation of China(No.42177184)。
文摘The Litang fault zone is an important seismogenic structure along the southeastern margin of the Tibetan Plateau.It caused the M71/4 earthquake in Litang in 1948 AD.The fault zone intersects the Sichuan-Xizang transportation corridor and poses a serious risk to its safe operation.This study,utilizing high-resolution remote sensing interpretation,field geological verification,UAV photogrammetry,UAV LiDAR,paleoearthquake trench excavation,and AMS^(14)C and OSL dating methods,reveals the geometric structure,slip rates,paleoearthquake sequence,and earthquake rupture segmentation of the Litang fault zone;analyzes the rupture distribution range of the 1729 AD Litang earthquake and estimates its magnitude.The study indicates that the Litang fault zone is a relatively immature strike-slip fault,which has developed as a new active fault zone within the Northwestern Sichuan sub-block during the southeastward material migration of the southeastern margin of the Tibetan Plateau.This reflects a transformation in the deformation model of the Northwestern Sichuan sub-block crust from the‘Rigid Block’model to the‘Continuous Deformation’model.
基金supported by the Major Program of the National Natural Science Foundation of China (Grant No.42090055)the National Major Scientific Instruments and Equipment Development Projects of China (Grant No.41827808)the National Nature Science Foundation of China (Grant No.42207216).
文摘The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and the internal component of a landslide.Therefore,considering the strength changes of the sliding zone with seepage effects,they correspond with the actual hydrogeological circumstances.To investigate the shear behavior of sliding zone soil under various seepage pressures,24 samples were conducted by a self-developed apparatus to observe the shear strength and measure the permeability coefficients at different deformation stages.After seepage-shear tests,the composition of clay minerals and microscopic structure on the shear surface were analyzed through X-ray and scanning electron microscope(SEM)to understand the coupling effects of seepage on strength.The results revealed that the sliding zone soil exhibited strain-hardening without seepage pressure.However,the introduction of seepage caused a significant reduction in shear strength,resulting in strain-softening characterized by a three-stage process.Long-term seepage action softened clay particles and transported broken particles into effective seepage channels,causing continuous damage to the interior structure and reducing the permeability coefficient.Increased seepage pressure decreased the peak strength by disrupting occlusal and frictional forces between sliding zone soil particles,which carried away more clay particles,contributing to an overhead structure in the soil that raised the permeability coefficient and decreased residual strength.The internal friction angle was less sensitive to variations in seepage pressure than cohesion.
基金National Natural Science Foundation of China,No.41930865Project for Innovative Capacity Improvement in Hebei Province,No.225A4201D。
文摘Nitrate(NO_(3)^(-))accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO_(3)^(-)content in intensive agricultural regions.Agricultural land-use change(ALUC),typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing factor.This study evaluated the changes in NO_(3)^(-)accumulation and transport in the deep vadose zone(DVZ,below the root zone),and the groundwater NO_(3)^(-)content associated with ALUC from grain to vegetable fields in the North China Plain(NCP).The ALUC from grain to vegetable resulted in nitrate–nitrogen(NO_(3)^(-)-N)accumulation in DVZ increased by 235.5 kg ha^(-1)m^(-1)(163.2%)in the piedmont plain and 224.9 kg ha^(-1)m^(-1)(102.7%)in the central plain,respectively.This change accelerated downward transport velocity in the DVZ(from 0.81±0.47 to 0.89±0.55 m yr^(-1)in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr^(-1)in the central plain)and increased NO_(3)^(-)leaching fluxes.High transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont plain.The impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.
基金funded by the National Key R&D Program of China (Grant No. 2021YFC3000704)the National Natural Science Foundation of China (Grant No. 42125401)the Central Public-interest Scientific Institution Basal Research Fund (Grant No. CEAIEF20240401)。
文摘The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthquake risk zones. In this study, we leveraged a dense seismic array to investigate the high-resolution shallow crust shear wave velocity(Vs) structure beneath the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone, one of the most complex parts of the eastern boundary of the South Chuan–Dian Block. We analyzed the distribution of microseismic events detected between November 2022 and February 2023 based on the fine-scale Vs model obtained. The microseismicity in the study region was clustered into three groups, all spatially related to major faults in this region. These microseismic events indicate near-vertical fault planes, consistent with the fault geometry revealed by other researchers.Moreover, these microseismic events are influenced by the impoundment of the downstream Baihetan Reservoir and the complex tectonic stress near the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone. The depths of these microseismic events are shallower in the junction zone, whereas moving south along the Xiaojiang Fault Zone, the microseismic events become deeper.Additionally, we compared our fine-scale local Vs model with velocity models obtained by other researchers and found that our model offers greater detail in characterizing subsurface heterogeneity while demonstrating improved reliability in delineating fault systems.
基金support from the National Natural Science Foundation of China (No. U1960202)the Opening Foundation from Shanghai Engineering Research Center of Hot Manufacturing, China (No. 18DZ2253400)。
文摘This work focuses on the influence of Al content on the precipitation of nanoprecipitates,growth of prior austenite grains(PAGs),and impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two experimental shipbuilding steels after being subjected to high-heat input welding at 400 kJ·cm^(-1).The base metals (BMs) of both steels contained three types of precipitates Type Ⅰ:cubic (Ti,Nb)(C,N),Type Ⅱ:precipitate with cubic (Ti,Nb)(C,N) core and Nb-rich cap,and Type Ⅲ:ellipsoidal Nb-rich precipitate.In the BM of 60Al and 160Al steels,the number densities of the precipitates were 11.37×10^(5) and 13.88×10^(5) mm^(-2),respectively The 60Al and 160Al steel contained 38.12% and 6.39% Type Ⅲ precipitates,respectively.The difference in the content of Type Ⅲ precipitates in the 60Al steel reduced the pinning effect at the elevated temperature of the CGHAZ,which facilitated the growth of PAGs The average PAG sizes in the CGHAZ of the 60Al and 160Al steels were 189.73 and 174.7μm,respectively.In the 60Al steel,the low lattice mismatch among Cu_(2)S,TiN,and γ-Al_(2)O_(3)facilitated the precipitation of Cu_(2)S and TiN onto γ-Al_(2)O_(3)during welding,which decreased the number density of independently precipitated (Ti,Nb)(C,N) particles but increased that of γ-Al_(2)O_(3)–Ti N–Cu_(2)S particles.Thus abnormally large PAGs formed in the CGHAZ of the 60Al steel,and they reached a maximum size of 1 mm.These PAGs greatly reduced the microstructural homogeneity and consequently decreased the impact toughness from 134 (0.016wt%Al) to 54 J (0.006wt%Al)at-40℃.
基金financially supported by the National Key Research and Development Program of China (2022YFC3005600)the Foundation of the Anhui Educational Commission (2023AH051198)+1 种基金the National Natural Science Foundation of China (42125401 and 42104063)the Joint Open Fund of Mengcheng National Geophysical Observatory (MENGO-202201)。
文摘The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structure in the upper crust and seismogenic tectonics in the Hefei segment of this fault, we collected phase velocity dispersion data of fundamental mode Rayleigh waves from ambient noise cross-correlation functions of ~400 temporal seismographs in an area of approximately 80 × 70 km along the fault zone. The period band of the dispersion data was ~0.5–10 s. We inverted for the upper crustal three-dimensional(3-D) shear velocity model with azimuthal anisotropy from the surface to 10 km depth by using a 3-D direct azimuthal anisotropy inversion method. The inversion result shows the spatial distribution characteristics of the tectonic units in the upper crust. Additionally, the deformation of the Tan-Lu Fault Zone and its conjugated fault systems could be inferred from the anisotropy model. In particular, the faults that have remained active from the early and middle Pleistocene control the anisotropic characteristics of the upper crustal structure in this area. The direction of fast axes near the fault zone area in the upper crust is consistent with the strike of the faults, whereas for the region far away from the fault zone, the direction of fast axes is consistent with the direction of the regional principal stress caused by plate movement. Combined with the azimuthal anisotropy models in the deep crust and uppermost mantle from the surface wave and Pn wave, the different anisotropic patterns caused by the Tan-Lu Fault Zone and its conjugated fault system nearby are shown in the upper and lower crust. Furthermore,by using the double-difference method, we relocated the Lujiang earthquake series, which contained 32 earthquakes with a depth shallower than 10 km. Both the Vs model and earthquake relocation results indicate that earthquakes mostly occurred in the vicinity of structural boundaries with fractured media, with high-level development of cracks and small-scale faults jammed between more rigid areas.
基金National Key Research and Development Program of China(2023YFC2907904)National Natural Science Foundation of China(52374364)。
文摘High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9.
基金supported by the Key Project of the National Natural Science Foundation of China(U23B2091)the National Key R&D Program of China(2022YFC2905600)+1 种基金the Youth Project of the National Natural Science Foundation of China(52304104 and 52404157)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZB20240825).
文摘As the mine depth around the world increases,the temperature of the surrounding rock of the mining workface increases significantly.To control the heat hazards,the hot water in the mining floor is developed during mining to decrease the min-ing workface temperature while also developing geothermal energy.This method is called the co-exploitation of mine and geothermal energy(CMGE).The geothermal development may precipitate the large-scale failure of the nearby fault zone during the mining process.However,the evolution of shear slide and shear failure of fault under geothermal production/rein-jection during mining is missing.Therefore,a fully-coupled hydraulic mechanism(HM)double-medium model for CMGE was developed based on the measured data of the Chensilou mine.A comparative analysis of the mechanical response of fault between CMGE and single mining was conducted.The disturbance of geothermal production pressure and reinjection pressure under mining on fault stability were respectively expounded.The results indicate that:(1)The disturbance of geo-thermal reinjection amplifies the disturbance of mining on fault stability.The amplified effect resulted in a normal stress drop of the fault,further leading to a substantial increase in shear slide distance,failure area,and cumulative seismic moment of fault compared with the single mining process.(2)As the distance of reinjection well to the fault decreases,the fault failure intensity increases.Setting the production well within the fault is advantageous for controlling fault stability under CMGE.(3)The essence of the combined disturbance of CMGE on the nearby fault is the overlay of tensile stress disturbance on the fault rock mass of the mining and geothermal reinjection.Though the geothermal reinjection causes a minor normal stress drop of fault,it can result in a more serious fault failure under CMGE.This paper supplies a significant gap in understanding thenearby faults failure under CMGE.
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology under Grant 2024yjrc64the National Key R&D Program of China under Grant 2018YFC1504102。
文摘The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.
文摘Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. This is done by examining the acetabular placement in instances of hip dislocation after total hip arthroplasty (THA). Methodology: The authors searched 2653 patient records from 2015 to 2022 looking for patients who had total hip arthroplasty at our facility. For the analysis, 23 patients were culled from 64 individuals who exhibited post-THA dislocations, employing a stringent exclusion criterion, and the resultant acetabular angulation and anteversion were quantified utilizing PEEKMED software (Peek Health S.A., Portugal) upon radiographic evidence. Results: Within the operational timeframe, from the cohort of 2653 subjects, 64 presented with at least a singular incident of displacement. Post-exclusion criterion enforcement, 23 patients were eligible for inclusion. Of these, 10 patients conformed to the safe zone demarcated by Lewinnek for both inclination and anteversion angles, while 13 exhibited deviations from the prescribed anteversion and/or inclination benchmarks. Conclusion: Analysis of the 23 patients reveals that 13 did not confirm to be in the safe zone parameters for anteversion and/or inclination, whereas 10 were within the safe zone as per Lewinnek’s guidelines. This investigative review, corroborated by extant literature, suggests that the isolated consideration of the Lewinnek safe zone does not suffice as a solitary protective factor. It further posits that additional variables are equally critical as acetabular positioning and mandate individual assessment.
基金funded by the programs of the National Natural Science Foundation(Nos.42172086,41572060,U1133602)the Program of‘Yunling Scholar’of Yunnan province(2014)+1 种基金the Projects of the Yunnan Engineering Laboratory of Mineral Resources Prediction and Evaluation(YM Lab)(2010)the Innovation Team of Yunnan Province and KMUST(2008,2012).
文摘As one of the typical deposits in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province,the Daliangzi Pb-Zn deposit has a close genetic relationship with the structural system of the black/fracture zone formed under the action of the NWW-approximately EW strike-slip structures in the metallogenic province.The R1 black/fracture zone has a close relationship with ore forming;however,the mechanism of the rock-and ore-controlling action of the structural system remains unclear.Based on a detailed analysis of the tectonite-mineralized alteration lithofacies of the R1 black/fracture zone,the tectonite-mineralized alteration lithofacies zones can be divided into four types in succession outward from the Pb-Zn mineralization center(F_(5),F_(100),and other faults),i.e.,(1)the brecciated and stockwork-like Pb-Zn mineralization-complex breccia facies zone;(2)the stockwork-like Pb-Zn mineralization-simple breccia and cataclasite facies zone;(3)the veined pyrite-sulfide-dolomitic cataclasite facies zone;(4)the fine-veined calcite-black carbonized dolomite facies zone.With the evolution of the ore-forming fluid,the homogenization temperature decreases from Zone 1 to Zone 4;the salinity increases from Zone 1 to Zone 2 and then it decreases from Zones 3 and 4.The fluid density shows little change overall.The contents of Zn,Pb,Cu,Ga,Ge,Cd,Ag,and other metallogenic elements,Zn/Pb ratio,and CaO/MgO mole ratio decrease gradually from Zone 1 to Zone 4,and the REE fractionation,calcilization,silicification,and pyritization enhance gradually from Zone 1 to Zone 4.This series of changes is the product of diapirism(cryptoexplosion)of strike-slip structures and the black/fracture zone,among which the second-order structures derived from NWW-approximately EW-striking dextral shear-tension faults F_(1)and F_(15)control the brecciated and stockwork-like Pb-Zn mineralized complex breccia facies zones and the stockwork-like Pb-Zn mineralized simple breccia and cataclasite facies zones.Therefore,this paper establishes the zoning mode of tectonite-mineralized alteration lithofacies of the black/fracture zone and proposes that Zones 1 and 2 provide important prospecting criteria.
