China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteri...China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up： （1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.展开更多
Given the high alpine grassland coverage and intensive animal grazing activity, the ecosystem and livelihood of the herders are extremely vulnerable in the headwater region of the Yellow River. A series of programs ha...Given the high alpine grassland coverage and intensive animal grazing activity, the ecosystem and livelihood of the herders are extremely vulnerable in the headwater region of the Yellow River. A series of programs have been implemented by the Chinese government to restore degraded grasslands in this region, and major function-oriented zones(MFOZs) applied in 2014, have divided the region into three zones, i.e., the development prioritized, restricted, and prohibited zones, based on environmental carrying capacity, as well as the utilization intensity of grassland. This study identified various restoration approaches adopted in different MFOZs, and assessed the effects of the approaches in order to determine the most effective approaches. We collected 195 questionnaires from herders to analyze the effects of the various restoration approaches, and additional remote sensing and statistical data were also used for the analysis. Four distinct differences in the ecological and socioeconomic characteristics were found in three MFOZs.(1) Five technologies were applied in the study areas.(2) The grassland recovery rate was higher in development prioritized zones than in restricted and prohibited zones during 2000 and 2016, and especially high and very high coverage grasslands increased in the areas where crop-forage cultivation and grass seeding dominated in the prioritized zones.(3) The net income of households in the development prioritized zone was the best of all three zones.(4) The degree of awareness and willingness of herders to restore grassland was more positive in development prioritized zones than in restricted zones, where more herders adopted approaches with a combination of enclosure + deratization + crop-forage cultivation + warm shed. Based on these findings, it is recommended that decision-makers need to increase their efforts to narrow the gap of willingness and behavior between herders and other stakeholders, such as researchers and grassland administrators, in order to ensure grassland sustainability in the MFOZs. It is also beneficial to understand the effects of restoration on the ecological carrying capacities in different zones depending on the different development goals.展开更多
The effect of temperature on molten zone length was investigated through simulation to optimize the control of molten zone length during the experimental process. The temperature gradient distribution within the molte...The effect of temperature on molten zone length was investigated through simulation to optimize the control of molten zone length during the experimental process. The temperature gradient distribution within the molten zone during zone refining was simulated using COMSOL Multiphysics software and experimentally validated. The simulated molten zone length showed good agreement with the actual measured length. The experimental study of tellurium purification by zone refining was conducted under the following conditions: three passes of zone refining, a hydrogen flow rate of 0.5 L/min, and molten zone movement speeds of 0.5 and 1.0 mm/min. The results demonstrated that the removal efficiencies of impurities such as Ca and Cu exceeded 95%, while the removal efficiency of phosphorus (P) reached over 70%. And the purity of tellurium reached 6N.展开更多
To ensure the efficient use of resources,particularly in water-scarce arid and semi-arid regions where abiotic stress threatens food security,assessing soil and climate suitability for specific crops is crucial.Simult...To ensure the efficient use of resources,particularly in water-scarce arid and semi-arid regions where abiotic stress threatens food security,assessing soil and climate suitability for specific crops is crucial.Simultaneously,food production must align with sustainable development goals by minimizing negative environmental impacts.Therefore,establishing agro-climatic suitability using a spatiotemporal approach is essential.This involves three key steps:first,determining the climatically appropriate months based on the species’requirements(temporal suitability),and second,establishing the soil suitability of specific plots(spatial suitability).Following this,quantifying crop evapotranspiration allows for optimized water use.This study used climatic and soil variables from diverse data sources to characterize the study area.Subsequently,suitability classes for Portulaca oleracea were determined based on existing literature.Our analysis concerning temporal suitability revealed that June and July are the optimal months for sowing this species in all of the municipalities.Spatially,approximately 30%of the agricultural land use of the study area exhibits a highly suitable class in most municipalities.Both dimensions,the temporal and the spatially,were validated through Chi square(χ^(2))Goodness-of-Fit test and theχ^(2)test of independence,respectively.Consequently,for a one-month production cycle during periods of high suitability,estimated evapotranspiration values are between 210 and 245 mm.In brief,the study area demonstrates favorable agro-climatic conditions for P.oleracea cultivation in specific months of the year according to parameters used,with potential in a large proportion of agricultural land and achievable water requirements.展开更多
Root-zone temperature(RZT)strongly affects plant growth,nutrient uptake and tolerance to environmental stress,making its regulation a key challenge in greenhouse cultivation in cold climates.This study aimed to assess...Root-zone temperature(RZT)strongly affects plant growth,nutrient uptake and tolerance to environmental stress,making its regulation a key challenge in greenhouse cultivation in cold climates.This study aimed to assess the potential of passive techniques,namely black polyethylene mulch and row covers,for modifying RZT dynamics in lettuce(Lactuca sativa L.)production and to evaluate the predictive performance of the eXtreme Gradient Boosting(XGBoost)algorithm.Experiments were conducted in Iğdır,Türkiye,over a 61-day period,with soil temperature continuously monitored at depths of 1-30 cm under mulched and non-mulched conditions,alongside measurements of greenhouse air temperature both with and without row covers.The application of row covers increased internal air temperature by 5.8℃,while mulching raised RZT by 0.6-1.3℃,with effects diminishing at deeper layers.XGBoost modeling achieved high predictive accuracy,with RMSE values of 0.150-0.189◦C and R^(2)values above 0.99,and feature-importance analysis indicated that neighboring soil depths were the strongest predictors of RZT.These findings show that integrating row covers and mulching can stabilize the root-zone microclimate without active heating.The XGBoost model provides a robust tool for forecasting soil temperature and supports sustainable greenhouse production in cold regions.展开更多
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
As a water layer with significantly reduced dissolved oxygen(DO)in the ocean,the oxygen minimum zone(OMZ)plays a crucial role in regulating marine organism distribution,global material cycles,and climate change.Based ...As a water layer with significantly reduced dissolved oxygen(DO)in the ocean,the oxygen minimum zone(OMZ)plays a crucial role in regulating marine organism distribution,global material cycles,and climate change.Based on a systematic review of recent studies on OMZ,this paper summarizes the DO thresholds,structural characteristics,distribution patterns,formation and maintenance mechanisms,and driving factors of OMZ in the ocean in the context of global change.The DO thresholds of OMZ typically range from 20 to 100μmol L^(-1).Specifically,the threshold is mostly 20μmol L^(-1) in regions with intense OMZ,such as the Eastern Pacific and Northern Indian Oceans,while it is mostly 100μmol L^(-1) in regions with mild OMZ,including the Western Pacific and Atlantic.In terms of structure,the OMZ is mainly composed of three parts:the upper oxycline,the lower oxycline,and the OMZ core.Significant differences exist in the horizontal and vertical distributions of OMZ across different regions.OMZ is mainly concentrated in tropical and subtropical regions,with the widest distribution in the eastern tropical North Pacific.The upper boundary of OMZ is shallower(50-150 m)in significantly affected regions,whereas it is below 200 m in less affected regions.The formation of OMZ is governed by the continuous consumption of DO in the ocean interior,and the water exchange restriction caused by seawater stratification,whereas the maintenance of the hypoxic state of OMZ relies on two positive feedbacks:increased microbial oxygen consumption due to reduced animal feeding,and increased oxygen consumption by anaerobic metabolic products.In the context of global change,rising temperature is the main driver of OMZ expansion,reducing O_(2) solubility,increasing respiration and decomposition rates,and enhancing seawater stratification.Additionally,the structure and evolution of OMZ is also profoundly affected by ocean circulation such as thermohaline circulation,wind-driven circulation,and upwelling,as well as changes in wind stress,mesoscale eddies and freshwater flux.Future research should focus on establishing OMZ gradient thresholds and classification criteria based on the law of deoxygenation,improving the systematic understanding of the temporal and spatial variations of OMZ,and continuously strengthening studies on OMZ in the Western Pacific.展开更多
The Almus Fault Zone(AFZ)is one of the major splay faults of the North Anatolian Fault Zone(NAFZ)and is important for understanding its tectonic features and assessing regional seismic hazards.This research presents t...The Almus Fault Zone(AFZ)is one of the major splay faults of the North Anatolian Fault Zone(NAFZ)and is important for understanding its tectonic features and assessing regional seismic hazards.This research presents the integration of morphometric indices to quantitatively assess the spatial variation of tectonic activity along the AFZ.The AFZ is an active fault with both strike-slip and normal fault components and consists of two main branches,Mercimekdağı-Çamdere Fault(MÇF)and Tokat Fault(TF)segments.This study aims to assess the relative tectonic activity of the AFZ using various morphometric indices,based on a 10 m resolution DEM,with the aid of ArcGIS and MATLAB software.For this purpose,morphometric indices such as hypsometric integral(HI:0.35-0.65),mountain front sinuosity(Smf:1.3-1.44),valley floor width-height ratio(Vf:0.15-2.28),asymmetry factor(AF:23-77),drainage basin shape(Bs:1.13-6.10)and normalized steepness index(ksn:1-498)were applied to 53 drainage basins.When the Smf and mean Vf indices results were evaluated,it was calculated that the uplift ratio of the region was more than 0.5 mm/yr.The spatial distribution of the relative tectonic activity(Iat)of the area was revealed by combining the obtained morphometric indices analysis results.According to the Iat result,it was concluded that the MercimekdağıÇamdere Fault and Tokat Fault segments have high tectonic activity,but the Mercimekdağı-Çamdere Fault segment has higher tectonic activity.The results obtained were also confirmed by field observations.This research provides valuable information for the evaluation of tectonic activity in drainage systems controlled by splay faults.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
An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of a...An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of adverse geological conditions in deep-buried tunnel construction.The installation techniques for microseismic sensors were optimized by mounting sensors at bolt ends which significantly improves signal-to-noise ratio(SNR)and anti-interference capability compared to conventional borehole placement.Subsequently,a 3D wave velocity evolution model that incorporates construction-induced disturbances was established,enabling the first visualization of spatiotemporal variations in surrounding rock wave velocity.It finds significant wave velocity reduction near the tunnel face,with roof and floor damage zones extending 40–50 m;wave velocities approaching undisturbed levels at 15 m ahead of the working face and on the laterally undisturbed side;pronounced spatial asymmetry in wave velocity distribution—values on the left side exceed those on the right,with a clear stress concentration or transition zone located 10–15 m;and systematically lower velocities behind the face than in front,indicating asymmetric rock damage development.These results provide essential theoretical support and practical guidance for optimizing dynamic construction strategies,enabling real-time adjustment of support parameters,and establishing safety early warning systems in deep-buried tunnel engineering.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
The number and diversity of inhibitory neurons(INs)increased substantially during mammalian brain evolution.However,the generative mechanisms of the vast repertoire of human INs remain elusive.We performed spatial and...The number and diversity of inhibitory neurons(INs)increased substantially during mammalian brain evolution.However,the generative mechanisms of the vast repertoire of human INs remain elusive.We performed spatial and single-cell transcriptomics of human medial ganglionic eminence(hMGE),a pivotal source of cortical and subpallial INs,and built the trajectories of hMGE-derived cells during brain development.We identified spatiotemporally and molecularly segregated progenitor cell populations fated to produce distinct IN types.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
It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of ...It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.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
基金Key Project of National Natural Science Foundation of China, No.41371409 National Key Technology R＆D Program, No.2013BAC03B00
文摘China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up： （1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.
基金The National Key Research and Development Program of China(2016YFC0501906,2016YFC0503700).
文摘Given the high alpine grassland coverage and intensive animal grazing activity, the ecosystem and livelihood of the herders are extremely vulnerable in the headwater region of the Yellow River. A series of programs have been implemented by the Chinese government to restore degraded grasslands in this region, and major function-oriented zones(MFOZs) applied in 2014, have divided the region into three zones, i.e., the development prioritized, restricted, and prohibited zones, based on environmental carrying capacity, as well as the utilization intensity of grassland. This study identified various restoration approaches adopted in different MFOZs, and assessed the effects of the approaches in order to determine the most effective approaches. We collected 195 questionnaires from herders to analyze the effects of the various restoration approaches, and additional remote sensing and statistical data were also used for the analysis. Four distinct differences in the ecological and socioeconomic characteristics were found in three MFOZs.(1) Five technologies were applied in the study areas.(2) The grassland recovery rate was higher in development prioritized zones than in restricted and prohibited zones during 2000 and 2016, and especially high and very high coverage grasslands increased in the areas where crop-forage cultivation and grass seeding dominated in the prioritized zones.(3) The net income of households in the development prioritized zone was the best of all three zones.(4) The degree of awareness and willingness of herders to restore grassland was more positive in development prioritized zones than in restricted zones, where more herders adopted approaches with a combination of enclosure + deratization + crop-forage cultivation + warm shed. Based on these findings, it is recommended that decision-makers need to increase their efforts to narrow the gap of willingness and behavior between herders and other stakeholders, such as researchers and grassland administrators, in order to ensure grassland sustainability in the MFOZs. It is also beneficial to understand the effects of restoration on the ecological carrying capacities in different zones depending on the different development goals.
基金financial support from the National Key Research and Development Program of China(No.2023YFC2907904)the National Natural Science Foundation of China(Nos.52374364,52104355,52074363)+1 种基金National Sustainable Development Agenda Innovation Demonstration Zones:Provincial Special“Open Competition”Project in Chenzhou,China(No.2022sfq57)Postdoctoral Innovation Talent Support Program,China(No.BX20230438)。
文摘The effect of temperature on molten zone length was investigated through simulation to optimize the control of molten zone length during the experimental process. The temperature gradient distribution within the molten zone during zone refining was simulated using COMSOL Multiphysics software and experimentally validated. The simulated molten zone length showed good agreement with the actual measured length. The experimental study of tellurium purification by zone refining was conducted under the following conditions: three passes of zone refining, a hydrogen flow rate of 0.5 L/min, and molten zone movement speeds of 0.5 and 1.0 mm/min. The results demonstrated that the removal efficiencies of impurities such as Ca and Cu exceeded 95%, while the removal efficiency of phosphorus (P) reached over 70%. And the purity of tellurium reached 6N.
文摘To ensure the efficient use of resources,particularly in water-scarce arid and semi-arid regions where abiotic stress threatens food security,assessing soil and climate suitability for specific crops is crucial.Simultaneously,food production must align with sustainable development goals by minimizing negative environmental impacts.Therefore,establishing agro-climatic suitability using a spatiotemporal approach is essential.This involves three key steps:first,determining the climatically appropriate months based on the species’requirements(temporal suitability),and second,establishing the soil suitability of specific plots(spatial suitability).Following this,quantifying crop evapotranspiration allows for optimized water use.This study used climatic and soil variables from diverse data sources to characterize the study area.Subsequently,suitability classes for Portulaca oleracea were determined based on existing literature.Our analysis concerning temporal suitability revealed that June and July are the optimal months for sowing this species in all of the municipalities.Spatially,approximately 30%of the agricultural land use of the study area exhibits a highly suitable class in most municipalities.Both dimensions,the temporal and the spatially,were validated through Chi square(χ^(2))Goodness-of-Fit test and theχ^(2)test of independence,respectively.Consequently,for a one-month production cycle during periods of high suitability,estimated evapotranspiration values are between 210 and 245 mm.In brief,the study area demonstrates favorable agro-climatic conditions for P.oleracea cultivation in specific months of the year according to parameters used,with potential in a large proportion of agricultural land and achievable water requirements.
文摘Root-zone temperature(RZT)strongly affects plant growth,nutrient uptake and tolerance to environmental stress,making its regulation a key challenge in greenhouse cultivation in cold climates.This study aimed to assess the potential of passive techniques,namely black polyethylene mulch and row covers,for modifying RZT dynamics in lettuce(Lactuca sativa L.)production and to evaluate the predictive performance of the eXtreme Gradient Boosting(XGBoost)algorithm.Experiments were conducted in Iğdır,Türkiye,over a 61-day period,with soil temperature continuously monitored at depths of 1-30 cm under mulched and non-mulched conditions,alongside measurements of greenhouse air temperature both with and without row covers.The application of row covers increased internal air temperature by 5.8℃,while mulching raised RZT by 0.6-1.3℃,with effects diminishing at deeper layers.XGBoost modeling achieved high predictive accuracy,with RMSE values of 0.150-0.189◦C and R^(2)values above 0.99,and feature-importance analysis indicated that neighboring soil depths were the strongest predictors of RZT.These findings show that integrating row covers and mulching can stabilize the root-zone microclimate without active heating.The XGBoost model provides a robust tool for forecasting soil temperature and supports sustainable greenhouse production in cold regions.
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(Grant Nos.42206135,42476204)the Shandong Provincial Natural Science Foundation(Grant Nos.ZR2025MS664,ZR2025MS611,ZR2022QD019).
文摘As a water layer with significantly reduced dissolved oxygen(DO)in the ocean,the oxygen minimum zone(OMZ)plays a crucial role in regulating marine organism distribution,global material cycles,and climate change.Based on a systematic review of recent studies on OMZ,this paper summarizes the DO thresholds,structural characteristics,distribution patterns,formation and maintenance mechanisms,and driving factors of OMZ in the ocean in the context of global change.The DO thresholds of OMZ typically range from 20 to 100μmol L^(-1).Specifically,the threshold is mostly 20μmol L^(-1) in regions with intense OMZ,such as the Eastern Pacific and Northern Indian Oceans,while it is mostly 100μmol L^(-1) in regions with mild OMZ,including the Western Pacific and Atlantic.In terms of structure,the OMZ is mainly composed of three parts:the upper oxycline,the lower oxycline,and the OMZ core.Significant differences exist in the horizontal and vertical distributions of OMZ across different regions.OMZ is mainly concentrated in tropical and subtropical regions,with the widest distribution in the eastern tropical North Pacific.The upper boundary of OMZ is shallower(50-150 m)in significantly affected regions,whereas it is below 200 m in less affected regions.The formation of OMZ is governed by the continuous consumption of DO in the ocean interior,and the water exchange restriction caused by seawater stratification,whereas the maintenance of the hypoxic state of OMZ relies on two positive feedbacks:increased microbial oxygen consumption due to reduced animal feeding,and increased oxygen consumption by anaerobic metabolic products.In the context of global change,rising temperature is the main driver of OMZ expansion,reducing O_(2) solubility,increasing respiration and decomposition rates,and enhancing seawater stratification.Additionally,the structure and evolution of OMZ is also profoundly affected by ocean circulation such as thermohaline circulation,wind-driven circulation,and upwelling,as well as changes in wind stress,mesoscale eddies and freshwater flux.Future research should focus on establishing OMZ gradient thresholds and classification criteria based on the law of deoxygenation,improving the systematic understanding of the temporal and spatial variations of OMZ,and continuously strengthening studies on OMZ in the Western Pacific.
文摘The Almus Fault Zone(AFZ)is one of the major splay faults of the North Anatolian Fault Zone(NAFZ)and is important for understanding its tectonic features and assessing regional seismic hazards.This research presents the integration of morphometric indices to quantitatively assess the spatial variation of tectonic activity along the AFZ.The AFZ is an active fault with both strike-slip and normal fault components and consists of two main branches,Mercimekdağı-Çamdere Fault(MÇF)and Tokat Fault(TF)segments.This study aims to assess the relative tectonic activity of the AFZ using various morphometric indices,based on a 10 m resolution DEM,with the aid of ArcGIS and MATLAB software.For this purpose,morphometric indices such as hypsometric integral(HI:0.35-0.65),mountain front sinuosity(Smf:1.3-1.44),valley floor width-height ratio(Vf:0.15-2.28),asymmetry factor(AF:23-77),drainage basin shape(Bs:1.13-6.10)and normalized steepness index(ksn:1-498)were applied to 53 drainage basins.When the Smf and mean Vf indices results were evaluated,it was calculated that the uplift ratio of the region was more than 0.5 mm/yr.The spatial distribution of the relative tectonic activity(Iat)of the area was revealed by combining the obtained morphometric indices analysis results.According to the Iat result,it was concluded that the MercimekdağıÇamdere Fault and Tokat Fault segments have high tectonic activity,but the Mercimekdağı-Çamdere Fault segment has higher tectonic activity.The results obtained were also confirmed by field observations.This research provides valuable information for the evaluation of tectonic activity in drainage systems controlled by splay faults.
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support of the National Natural Science Foundation of China(No.52274176)the Guangdong Province Key Areas R&D Program(No.2022B0101070001)+5 种基金Chongqing Elite Innovation and Entrepreneurship Leading talent Project(No.CQYC20220302517)the Chongqing Natural Science Foundation Innovation and Development Joint Fund(No.CSTB2022NSCQ-LZX0079)the National Key Research and Development Program Young Scientists Project(No.2022YFC2905700)the Chongqing Municipal Education Commission“Shuangcheng Economic Circle Construction in Chengdu-Chongqing Area”Science and Technology Innovation Project(No.KJCX2020031)the Fundamental Research Funds for the Central Universities(No.2024CDJGF-009)the Key Project for Technological Innovation and Application Development in Chongqing(No.CSTB2025TIAD-KPX0029).
文摘An innovative real-time monitoring method for surrounding rock damage based on microseismic time-lapse double-difference tomography is proposed for delayed dynamic damage identification and insufficient detection of adverse geological conditions in deep-buried tunnel construction.The installation techniques for microseismic sensors were optimized by mounting sensors at bolt ends which significantly improves signal-to-noise ratio(SNR)and anti-interference capability compared to conventional borehole placement.Subsequently,a 3D wave velocity evolution model that incorporates construction-induced disturbances was established,enabling the first visualization of spatiotemporal variations in surrounding rock wave velocity.It finds significant wave velocity reduction near the tunnel face,with roof and floor damage zones extending 40–50 m;wave velocities approaching undisturbed levels at 15 m ahead of the working face and on the laterally undisturbed side;pronounced spatial asymmetry in wave velocity distribution—values on the left side exceed those on the right,with a clear stress concentration or transition zone located 10–15 m;and systematically lower velocities behind the face than in front,indicating asymmetric rock damage development.These results provide essential theoretical support and practical guidance for optimizing dynamic construction strategies,enabling real-time adjustment of support parameters,and establishing safety early warning systems in deep-buried tunnel engineering.
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.
文摘The number and diversity of inhibitory neurons(INs)increased substantially during mammalian brain evolution.However,the generative mechanisms of the vast repertoire of human INs remain elusive.We performed spatial and single-cell transcriptomics of human medial ganglionic eminence(hMGE),a pivotal source of cortical and subpallial INs,and built the trajectories of hMGE-derived cells during brain development.We identified spatiotemporally and molecularly segregated progenitor cell populations fated to produce distinct IN types.
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.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U22A20162,31900583,32071351,81772400,82102604,and 81960395)the Natural Science Foundation of Guangzhou City(No.201807010031)+5 种基金the Foundation of Shenzhen Committee for Science and Technology Innovation(Nos.JCYJ20190809142211354,and GJHZ20180929160004704)the Sanming Project of Medicine in Shenzhen(No.SZSM201911002)the Beijing Municipal Health Commission(Nos.BMHC-2021-6,BMHC-2019-9,BMHC-2018-4,and PXM2020_026275_000002)the AOCMF Translational approaches for bone constructs(No.AOCMF-21-04S)the Sun Yatsen University Clinical Research 5010 Program(No.2019009)the Academic Affairs Office of Sun Yat-sen University(Nos.202211583,and 202211589).
文摘It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.
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.
