The effect of rolling schedules on the ridging resistance of ultra-thin ferritic stainless steel(FSS)430 foil was evaluated by studying the microstructure and texture.The results show that specimens processed with thr...The effect of rolling schedules on the ridging resistance of ultra-thin ferritic stainless steel(FSS)430 foil was evaluated by studying the microstructure and texture.The results show that specimens processed with three-pass cold rolling under the reductions of 40%,40%and 31%,respectively,exhibit improved ridging resistance owing to the microstructural refinement and the texture structure optimization.A nearly 40%reduction of ridging height can be achieved using the proposed rolling schedule compared to the other two rolling schedules.In addition,the effect of annealing temperature after cold rolling on the ridging resistance of FSS 430 foil is also found to be crucial,and an optimal annealing temperature of 900℃ is obtained for FSS 430 foil with high ridging resistance.Overall,the improvement in the ridging resistance of FSS 430 foil can be attributed to the reduction in the fraction of{001}<110>and{114}<110>components by optimization of the rolling and annealing processes.展开更多
The effect of hot band annealing processes—batch annealing and continuous annealing—on the texture evolution and ridging performance of ferritic stainless steel was investigated.The surface and central layers of the...The effect of hot band annealing processes—batch annealing and continuous annealing—on the texture evolution and ridging performance of ferritic stainless steel was investigated.The surface and central layers of the hot band exhibited strong shear and plane deformation textures,respectively.After batch annealing,the texture intensity of the hot-rolled sheet texture significantly decreased,and a weak recrystallization texture appeared,while fully recrystallized grains occurred after continuous annealing.A complete recrystallized{111}texture was obtained after recrystallization annealing.The sheet subjected to continuous annealing exhibited the highest intensity of{111}texture,which was accompanied by a dispersed grain orientation distribution,resulting in the lowest ridging height.展开更多
The microstructure, texture evolution and spatial orientation distribution during cold rolling and the subsequent annealing as well as formability and ridging of a Sn-bearing ferritic stainless steel under different h...The microstructure, texture evolution and spatial orientation distribution during cold rolling and the subsequent annealing as well as formability and ridging of a Sn-bearing ferritic stainless steel under different hot band annealing temperatures were investigated. The four hot bands with annealing temperatures of 900, 950, 1000 and 1050 °C were all cold-rolled to 80% reductions and then were annealed at the same temperature of 900 °C. The results show that optimizing hot band annealing process is benefi cial to reduce the amount of {001} <110> grains and weaken the texture intensity, and thus, to reduce ridging and improve formability. In the present study, the fi nal sheets with hot band annealing temperature of 900 °C possess small and inhomogeneous grains with a large amount of {001} <110> orientations, which deteriorates the formability and increases the ridging. In comparison, the fi nal sheets with hot band annealing temperature of 950 °C are comprised of uniform and equiaxed <111>//ND(ND: normal direction) recrystallized grains with a high texture intensity favorable for the improvement in r value and surface quality. However, when hot band annealing temperature further increases to 1000 and 1050 °C, it shows a sharp decrease in r value and a remarkable increase in ridging as a result of a reduction in γ-fi ber texture intensity and an increase in grain size in the fi nal sheets. Suitable controlling and optimizing hot band annealing process is essential to improve the formability and reduce the ridging.展开更多
With consideration of highly-efficient use of natural resources, reducing production cost and construction of high-standard agricultural fields, rice production of good seed＋fertilizer investment is reformed on basis...With consideration of highly-efficient use of natural resources, reducing production cost and construction of high-standard agricultural fields, rice production of good seed＋fertilizer investment is reformed on basis of research of smash-ridging technology, and rice smash-ridging ecological and highly-efficient cultivation was pro- posed, namely, smash-ridging based deeply poughing and rotary tillage technology was used to loosen soils deeply, with the depth from 13-15 cm to 26-28 cm. Fur- thermore, after soils softening, seedling slinging or direct seeding was adopted, which is dominated by natural rainfall and supplemented by artificial irrigation. The test proved that the technology help increasing yield and profits over 20%, with chemical fertilizer reduced by more than 10%, and labor cost reduced by 10%. What＇s more, if the technology applied once, no-tillage or slight tillage is recom- mended in the field, which would maintain original eco-conditions of soils and reach high yield, with energy, water, labor costs reduced in an environment-friendly way.展开更多
Using smashing ridging tillage machine and smashing ridging technology invented by the authors, transformation test of saline-alkali land by smashing ridging was conducted respectively in Xinjiang and Shaanxi during 2...Using smashing ridging tillage machine and smashing ridging technology invented by the authors, transformation test of saline-alkali land by smashing ridging was conducted respectively in Xinjiang and Shaanxi during 2015 -2016. The results showed, in severe saline-alkali soil of Xin-jiang ,after growing cotton by smashing ridging, total salt in soil decreased by 31.31 %, cotton production increased by 48.80%, and salinity level declined from severe to moderate; in mild saline-alkali soil of Shaanxi, after growing summer corn by smashing ridging, total salt in soil decreased by 42.37%, corn yield increased by 34.83%, salinity degree changed from mild desalination to normal farmland ; in Ningxia, Inner Mongolia 7 Gansu ,Jilin, Henan, Hebei, and so on, smashing ridging tillage practice in different types of saline-alkali land was conducted ; according to the salt reduction and yield increase effects of saline-alkali land after smashing ridging, the development prospect of smashing ridging technique in improvement and application of saline-alkali land was proposed.展开更多
An approach to optimize the processing parameters to get superior ridging resistance and mechanical properties in commercial production of 430 ferritic stainless steel has been studied. Attention was also paid to impr...An approach to optimize the processing parameters to get superior ridging resistance and mechanical properties in commercial production of 430 ferritic stainless steel has been studied. Attention was also paid to improve productivity and energy saving without hampering the surface and mechanical property aspects of the material. Hot rolled coils annealed by slow cooling under insulated cover exhibit better ridging resistance than bell annealing treatment with a minor decrease in ductility. Soaking temperature prior to hot rolling has a significant effect on ridging resistance.展开更多
The effects of the finisher entry temperatures（FETs） on the surface ridging behavior for an ultra-purified21%Cr ferritic stainless steel have been investigated. The results indicate that decreasing the FET facilitat...The effects of the finisher entry temperatures（FETs） on the surface ridging behavior for an ultra-purified21%Cr ferritic stainless steel have been investigated. The results indicate that decreasing the FET facilitates the formation of in-grain shear bands in the hot rolled slab. The in-grain shear bands supplied recrystallization nucleation sites in grains during subsequent annealing through coalescence of subgrains, which is beneficial to refine the microstructures and intensify the {111}//ND textures. This effect will evolve to the final cold rolled and annealed sheet. The micro-texture analysis indicates that the formation of grain colony in the final sheet is weakened by decreasing the FET. Then, the surface ridging resistance of FSS is enhanced due to the optimizing of micro-texture distribution.展开更多
In ferritic stainless steels, a significant non-uniform recrystallization orientation and a substantial texture gradient usually occur, which can degrade the ridging resistance of the final sheets. To improve the homo...In ferritic stainless steels, a significant non-uniform recrystallization orientation and a substantial texture gradient usually occur, which can degrade the ridging resistance of the final sheets. To improve the homogeneity of the recrystallization orientation and reduce the texture gradient in ultra-purified 17%Cr ferritic stainless steel, in this work, we performed conventional and asymmetric rolling processes and conducted macro and micro-texture analyses to investigate texture evolution under different cold-rolling conditions. In the conventional rolling specimens, we observed that the deformation was not uniform in the thickness direction, whereas there was homogeneous shear deformation in the asymmetric rolling specimens as well as the formation of uniform recrystallized grains and random orientation grains in the final annealing sheets. As such, the ridging resistance of the final sheets was significantly improved by employing the asymmetric rolling process. This result indicates with certainty that the texture gradient and orientation inhomogeneity can be attributed to non-uniform deformation, whereas the uniform orientation gradient in the thickness direction is explained by the increased number of shear bands obtained in the asymmetric rolling process.展开更多
In order to understand the effect of the solidification structure on the formability of ultra low carbon ferritic stainless steel （FSS） ,this work studies the ridging phenomenon and the deep-drawing property in deta...In order to understand the effect of the solidification structure on the formability of ultra low carbon ferritic stainless steel （FSS） ,this work studies the ridging phenomenon and the deep-drawing property in detail and the research method was X-ray diffraction （XRD） and scanning electron microscope （SEM） technique. The result shows that the columnar grain specimen had a higher ridging height than the equiaxed grain specimen, which was mainly attributed to the formation of grain colonies in the columnar grain specimen. After final recrystallization annealing, the equiaxed grain specimen obtained a high-intensity T-fiber texture and an excellent deep-drawing property.展开更多
Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influenci...Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient.This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation(ETC),Mann-Kendall test,Theil-Sen estimator,ridge regression analysis,and other relevant methods.The following findings were obtained:(1)at the pixel scale,the long-term monthly SM data from the European Space Agency Climate Change Initiative(ESA CCI)exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error(RMSE)of 0.014 m^(3)/m^(3);(2)from 2000 to 2022,the study area experienced significant increase in annual average SM,with a rate of 0.408×10^(-3)m^(3)/(m^(3)•a).Moreover,higher altitudes showed a notable upward trend,with SM increasing rates at 0.210×10^(-3)m^(3)/(m^(3)•a)between 1000 and 2000 m,0.530×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m,and 0.760×10^(-3)m^(3)/(m^(3)•a)at altitudes above 4000 m;(3)land surface temperature(LST),root zone soil moisture(RSM)(10-40 cm depth),and normalized difference vegetation index(NDVI)were identified as the primary factors influencing annual average SM,which accounted for 34.37%,24.16%,and 22.64%relative contributions,respectively;and(4)absolute contribution of LST was more significant in subareas at higher altitudes,with average absolute contributions of 0.800×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m and 0.500×10^(-2) m^(3)/(m^(3)•a)above 4000 m.This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas,highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas,providing valuable insights for ecological research and water resource management in these areas.展开更多
The complex and diverse nature of coal mining sites,including different landforms and working conditions,presents challenges for rehabilitation efforts.To address this,we conducted a comprehensive experimental study f...The complex and diverse nature of coal mining sites,including different landforms and working conditions,presents challenges for rehabilitation efforts.To address this,we conducted a comprehensive experimental study focusing on microbially induced calcium carbonate precipitation(MICP)remediation,considering the fracture characteristics of coal mining sites.The MICP-restored samples were subjected to confined/unconfined compressive strength,uniaxial/triaxial permeability,and souring tests to assess their restoration efficacy.The results showed that under similar mining conditions,the average depth of parallel fractures was 0.185 m for loess ridges,0.16 m for the valley,and 0.146 m for the blown-sand region,while the average depth for boundary fractures was 0.411 m for loess ridges,0.178 m for the valley,and 0.268 m for the blown-sand region.Notably,parallel fractures showed negligible filling in all landforms,whereas boundary fractures in the blown-sand region were completely filled with wind-deposited sand.The valley landform was filled with alluvium and wind-deposited sand,whereas the loess landform was filled with wind-deposited sand and loess.MICP-restored soil samples in all landforms achieved a strength comparable to remolded fracture-free soil samples.Across all landforms,the maximum permeability coefficient of MICP-restored soil samples closely matched that of remolded fracture-free soil samples.Under similar topographic and rainfall conditions MICP restorations scoured 31.3 g on blown-sand region,19.3 g on loess ridges,and 17.6 g on valleys.These research findings provide an experimental foundation for MICP repair of coal mining ground fractures.展开更多
The Chilean Pampean flat slab subduction segment is characterized by the nearly horizontal subduction of the Nazca Plate within the depth range of 100-120 km.Numerous seismic tomography studies have been conducted to ...The Chilean Pampean flat slab subduction segment is characterized by the nearly horizontal subduction of the Nazca Plate within the depth range of 100-120 km.Numerous seismic tomography studies have been conducted to investigate its velocity structure;however,they have used only seismic body wave data or surface wave data.As a result,the existing velocity models in the region may have relatively large uncertainties.In this study,we use body wave arrival times from earthquakes occurring in central Chile between 2014 and 2019,as well as Rayleigh wave phase velocity maps at periods of 5-80 s from ambient noise empirical Green’s functions in Chile.By jointly using body wave arrival times and surface wave dispersion data,we refine the VS model and improve earthquake locations in the central Chile subduction zone.Compared with previous velocity models,our velocity model better reveals an eastward-dipping high-velocity plate representing the subducting Nazca Plate,which is 40-50 km thick and is more consistent with the slab thickness estimated by receiver function imaging and thermal modeling.Overall,the intraslab seismicity distribution spatially correlates well with the slab high-velocity anomalies except along the subduction paths of the CopiapóRidge and Juan Fernández Ridge.Additionally,parallel low-velocity stripes are imaged beneath the subducting plate,which are likely associated with the accumulated melts.The joint inversion velocity model also resolves widespread low-velocity anomalies in the crust beneath the Central Volcanic Zone of the central Andes,likely representing crustal magma chambers for various volcanoes.展开更多
β-ray-induced X-ray spectroscopy(BIXS)is a promising method for tritium detection in solid materials because of its unique advantages,such as large detection depth,nondestructive testing capabilities,and low requirem...β-ray-induced X-ray spectroscopy(BIXS)is a promising method for tritium detection in solid materials because of its unique advantages,such as large detection depth,nondestructive testing capabilities,and low requirements for sample preparation.However,high-accuracy reconstruction of the tritium depth profile remains a significant challenge for this technique.In this study,a novel reconstruction method based on a backpropagation(BP)neural network algorithm that demonstrates high accuracy,broad applicability,and robust noise resistance is proposed.The average reconstruction error calculated using the BP network(8.0%)was much lower than that obtained using traditional numerical methods(26.5%).In addition,the BP method can accurately reconstruct BIX spectra of samples with an unknown range of tritium and exhibits wide applicability to spectra with various tritium distributions.Furthermore,the BP network demonstrates superior accuracy and stability compared to numerical methods when reconstructing the spectra,with a relative uncertainty ranging from 0 to 10%.This study highlights the advantages of BP networks in accurately reconstructing the tritium depth profile from BIXS and promotes their further application in tritium detection.展开更多
Palaeowind regime is an important component for reconstructing palaeoclimate and understanding ancient global circulation.We applied the beach-ridge thickness technique(BTT)and the longshore-bar thickness technique(LT...Palaeowind regime is an important component for reconstructing palaeoclimate and understanding ancient global circulation.We applied the beach-ridge thickness technique(BTT)and the longshore-bar thickness technique(LTT)to reconstruct the Early Cretaceous palaeowind velocities based on depositional records of Tanan Depression in Northeast Asia.The thickness of beach ridges and nearshore bars is the most important parameter for applying the BTT and the LTT methods.We identified 22 beach ridges and 23 nearshore bars based on drilling cores and wireline-log data in the Tanan Depression.Palaeowind velocities calculated by using the LTT method ranged from 10.84 to 13.66 m/s,showing a narrower range than those calculated by using the BTT method(7.58–15.93 m/s).We further analyzed the underlying factors causing the difference between the results derived from these two methods based on the sedimentary process of the beach ridge and the nearshore bar.The reconstructed wind regime was assumed to be the summer monsoon originating from the Mongol-Okhotsk Ocean before it had been completely enclosed,which provides valuable insight into the understanding of the atmospheric circulation in Northeast Asia during the Early Cretaceous.展开更多
We report new SHRIMP zircon U-Pb ages,zircon Lu-Hf isotopic and whole rock geochemical data from Permian granitoids located in the Alxa area of Inner Mongolia,China.In combination with published geochronological and g...We report new SHRIMP zircon U-Pb ages,zircon Lu-Hf isotopic and whole rock geochemical data from Permian granitoids located in the Alxa area of Inner Mongolia,China.In combination with published geochronological and geochemical data,the granitoids in the region can be divided into two age groups:ca.285 Ma and ca.269 Ma.The granitoids of the first group are mainly composed of calc-alkaline to high-K calc-alkaline,weakly peraluminous Ⅰ-type granodiorites with ε_(Hf)(t)values of-19.6 to-4.3,which demonstrates evidence of crustal reworking;the granitoids of the second group,however,mainly consist of A-type granites that are high-K calc-alkaline to shoshonite,metaluminous to weakly peraluminous,and have high 10,000×Ga/Al ratios(2.59-3.12)and ε_(Hf)(t)values ranging from-11.3 to-2.7,all of which demonstrates a mixed crust-mantle source.We interpret the granitoids of the first group to have formed during the subduction of Central Asian oceanic crust and the second group to have formed by the asthenospheric upwelling caused by the formation of slab windows during late ocean ridge subduction.展开更多
Seismic fault rupture can extend to the surface,and the resulting surface deformation can cause severe damage to civil engineering structures crossing the fault zones.Coseismic Surface Rupture Prediction Models(CSRPMs...Seismic fault rupture can extend to the surface,and the resulting surface deformation can cause severe damage to civil engineering structures crossing the fault zones.Coseismic Surface Rupture Prediction Models(CSRPMs)play a crucial role in the structural design of fault-crossing engineering and in the hazard analysis of fault-intensive areas.In this study,a new global coseismic surface rupture database was constructed by compiling 171 earthquake events(Mw:5.5-7.9)that caused surface rupture.In contrast to the fault classification in traditional empirical relationships,this study categorizes earthquake events as strike-slip,dip-slip,and oblique-slip.CSRPMs utilizing Bayesian ridge regression(BRR)were developed to estimate parameters such as surface rupture length,average displacement,and maximum displacement.Based on Bayesian theory,BRR combines the benefits of both ridge regression and Bayesian linear regression.This approach effectively addresses the issue of overfitting while ensuring the strong model robustness.The reliability of the CSRPMs was validated by residual analysis and comparison with post-earthquake observations from the 2023 Türkiye earthquake doublet.The BRR-CSRPMs with new fault classification criteria are more suitable for the probabilistic hazard analysis of complex fault systems and dislocation design of fault-crossing engineering.展开更多
The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate ch...The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.展开更多
Organisms have evolved a strain limiting mechanism,reflected as a non-linear elastic constitutive,to prevent large deformations from threatening soft tissue integrity.Compared with linear elastic substrates,the wrinkl...Organisms have evolved a strain limiting mechanism,reflected as a non-linear elastic constitutive,to prevent large deformations from threatening soft tissue integrity.Compared with linear elastic substrates,the wrinkle of films on non-linear elastic substrates has received less attention.In this article,a unique wrinkle evolution of the film-substrate system with a J-shaped non-linear stress-strain relation is reported.The result shows that a concave hexagonal array pattern is formed with the shrinkage strain of the film-substrate systems developing.As the interconnection of hexagonal arrays,a unit cell ridge network appears with properties such as chirality and helix.The subparagraph maze pattern formed with high compression is mainly composed of special single-cell ridge networks such as spiral single cores,chiral double cores,and combined multi-cores.This evolutionary model is highly consistent with the results of experiments,and it also predicts wrinkle morphology that has not yet been reported.These findings can serve as a novel explanation for the surface wrinkle of biological soft tissue,as well as provide references for the preparation of artificial biomaterials and programmable soft matter.展开更多
The Equatorial Atlantic Ocean,a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics,remains the focus of extensive research aimed at unraveling its evolution.However...The Equatorial Atlantic Ocean,a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics,remains the focus of extensive research aimed at unraveling its evolution.However,its complex structural setting and contentious formation timeline have posed significant challenges.Through a comprehensive review of contemporary scientific litera-ture,we have identified three distinct phases for its evolution:pre-breakup,syn-breakup,and post-breakup,providing more detailed in-sights into the tectonic evolution of the Equatorial Atlantic.Prior to 110 Myr,the African and South American Plates underwent stretching predominantly from North to South,with the emergence of the Parana plume.This condition has led to the formation of nu-merous fracture zones and a triple junction.During the syn-breakup phase,spanning from 110 Myr to 90 Myr,the central region of the Equatorial Atlantic fully opened up,establishing a connection between the northern and southern waterways.However,the develop-ment of multiple ridge segments separated by numerous fracture zones in the central Equatorial Atlantic exhibited considerable com-plexity.The underlying causes for these complex structural formations remain elusive.Following the Chicxulub meteorite impact around 66 Myr and the emergence of the Sierra Leone hotspot,a pair of oceanic plateau‘twins’and a series of seamount chains were formed as a result of mantle plume tails.Consequently,the timeline of the Equatorial Atlantic’s tectonic evolution has gradually be-come clearer.However,due to the extensive timescale and the multitude of events involved in its formation,disputes about the precise-timing of various events still remain.The evolution of the Equatorial Atlantic has witnessed numerous ridge propagations,hotspot formations,and meteorite impacts,highlighting the need for further investigation into their interactions.The absence of identified magnetic isochrons in the Equatorial region emphasizes the urgency of additional exploration and analysis of its geological and geo-physical data.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52105392 and 52275359)the Central Government Guided Local Science and Technology Development Fund Project(Grant No.YDZJSX2021A006)+1 种基金the Natural Foundation of Shanxi Province(Grant No.20210302123166)the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(Grant No.20210035).
文摘The effect of rolling schedules on the ridging resistance of ultra-thin ferritic stainless steel(FSS)430 foil was evaluated by studying the microstructure and texture.The results show that specimens processed with three-pass cold rolling under the reductions of 40%,40%and 31%,respectively,exhibit improved ridging resistance owing to the microstructural refinement and the texture structure optimization.A nearly 40%reduction of ridging height can be achieved using the proposed rolling schedule compared to the other two rolling schedules.In addition,the effect of annealing temperature after cold rolling on the ridging resistance of FSS 430 foil is also found to be crucial,and an optimal annealing temperature of 900℃ is obtained for FSS 430 foil with high ridging resistance.Overall,the improvement in the ridging resistance of FSS 430 foil can be attributed to the reduction in the fraction of{001}<110>and{114}<110>components by optimization of the rolling and annealing processes.
文摘The effect of hot band annealing processes—batch annealing and continuous annealing—on the texture evolution and ridging performance of ferritic stainless steel was investigated.The surface and central layers of the hot band exhibited strong shear and plane deformation textures,respectively.After batch annealing,the texture intensity of the hot-rolled sheet texture significantly decreased,and a weak recrystallization texture appeared,while fully recrystallized grains occurred after continuous annealing.A complete recrystallized{111}texture was obtained after recrystallization annealing.The sheet subjected to continuous annealing exhibited the highest intensity of{111}texture,which was accompanied by a dispersed grain orientation distribution,resulting in the lowest ridging height.
基金financially supported by the National Natural Science Foundation of China (No. U1860201)the Fundamental Research Funds for the Central Universities (No. 162704001)
文摘The microstructure, texture evolution and spatial orientation distribution during cold rolling and the subsequent annealing as well as formability and ridging of a Sn-bearing ferritic stainless steel under different hot band annealing temperatures were investigated. The four hot bands with annealing temperatures of 900, 950, 1000 and 1050 °C were all cold-rolled to 80% reductions and then were annealed at the same temperature of 900 °C. The results show that optimizing hot band annealing process is benefi cial to reduce the amount of {001} <110> grains and weaken the texture intensity, and thus, to reduce ridging and improve formability. In the present study, the fi nal sheets with hot band annealing temperature of 900 °C possess small and inhomogeneous grains with a large amount of {001} <110> orientations, which deteriorates the formability and increases the ridging. In comparison, the fi nal sheets with hot band annealing temperature of 950 °C are comprised of uniform and equiaxed <111>//ND(ND: normal direction) recrystallized grains with a high texture intensity favorable for the improvement in r value and surface quality. However, when hot band annealing temperature further increases to 1000 and 1050 °C, it shows a sharp decrease in r value and a remarkable increase in ridging as a result of a reduction in γ-fi ber texture intensity and an increase in grain size in the fi nal sheets. Suitable controlling and optimizing hot band annealing process is essential to improve the formability and reduce the ridging.
基金Supported by Fundamental Research Funds for Guangxi Academy of Agricultural Sciences(2014YZ07)Transformation Project of Scientific and Technological Achievements,Guangxi Academy of Agricultural Sciences(201405)~~
文摘With consideration of highly-efficient use of natural resources, reducing production cost and construction of high-standard agricultural fields, rice production of good seed＋fertilizer investment is reformed on basis of research of smash-ridging technology, and rice smash-ridging ecological and highly-efficient cultivation was pro- posed, namely, smash-ridging based deeply poughing and rotary tillage technology was used to loosen soils deeply, with the depth from 13-15 cm to 26-28 cm. Fur- thermore, after soils softening, seedling slinging or direct seeding was adopted, which is dominated by natural rainfall and supplemented by artificial irrigation. The test proved that the technology help increasing yield and profits over 20%, with chemical fertilizer reduced by more than 10%, and labor cost reduced by 10%. What＇s more, if the technology applied once, no-tillage or slight tillage is recom- mended in the field, which would maintain original eco-conditions of soils and reach high yield, with energy, water, labor costs reduced in an environment-friendly way.
基金Supported by National Science and Technology Support Program(2014BAD06B05)
文摘Using smashing ridging tillage machine and smashing ridging technology invented by the authors, transformation test of saline-alkali land by smashing ridging was conducted respectively in Xinjiang and Shaanxi during 2015 -2016. The results showed, in severe saline-alkali soil of Xin-jiang ,after growing cotton by smashing ridging, total salt in soil decreased by 31.31 %, cotton production increased by 48.80%, and salinity level declined from severe to moderate; in mild saline-alkali soil of Shaanxi, after growing summer corn by smashing ridging, total salt in soil decreased by 42.37%, corn yield increased by 34.83%, salinity degree changed from mild desalination to normal farmland ; in Ningxia, Inner Mongolia 7 Gansu ,Jilin, Henan, Hebei, and so on, smashing ridging tillage practice in different types of saline-alkali land was conducted ; according to the salt reduction and yield increase effects of saline-alkali land after smashing ridging, the development prospect of smashing ridging technique in improvement and application of saline-alkali land was proposed.
文摘An approach to optimize the processing parameters to get superior ridging resistance and mechanical properties in commercial production of 430 ferritic stainless steel has been studied. Attention was also paid to improve productivity and energy saving without hampering the surface and mechanical property aspects of the material. Hot rolled coils annealed by slow cooling under insulated cover exhibit better ridging resistance than bell annealing treatment with a minor decrease in ductility. Soaking temperature prior to hot rolling has a significant effect on ridging resistance.
基金supported by the Fundamental Research Funds for the Central Universities of China, the Scientific Research Fund of Liaoning Provincial Education Department under Grant No. L2015120the Open Research Fund from the State Key Laboratory of Rolling and Automation, Northeastern University, China (Grant No. 2015003)Part of this work was presented at the International Deep Drawing Research Group Conference (2015)
文摘The effects of the finisher entry temperatures（FETs） on the surface ridging behavior for an ultra-purified21%Cr ferritic stainless steel have been investigated. The results indicate that decreasing the FET facilitates the formation of in-grain shear bands in the hot rolled slab. The in-grain shear bands supplied recrystallization nucleation sites in grains during subsequent annealing through coalescence of subgrains, which is beneficial to refine the microstructures and intensify the {111}//ND textures. This effect will evolve to the final cold rolled and annealed sheet. The micro-texture analysis indicates that the formation of grain colony in the final sheet is weakened by decreasing the FET. Then, the surface ridging resistance of FSS is enhanced due to the optimizing of micro-texture distribution.
基金financially supported by the National Key R&D Program of China (2016YFB0300200)National Natural Science Foundation of China (Nos. U1660114 and 51174026)
文摘In ferritic stainless steels, a significant non-uniform recrystallization orientation and a substantial texture gradient usually occur, which can degrade the ridging resistance of the final sheets. To improve the homogeneity of the recrystallization orientation and reduce the texture gradient in ultra-purified 17%Cr ferritic stainless steel, in this work, we performed conventional and asymmetric rolling processes and conducted macro and micro-texture analyses to investigate texture evolution under different cold-rolling conditions. In the conventional rolling specimens, we observed that the deformation was not uniform in the thickness direction, whereas there was homogeneous shear deformation in the asymmetric rolling specimens as well as the formation of uniform recrystallized grains and random orientation grains in the final annealing sheets. As such, the ridging resistance of the final sheets was significantly improved by employing the asymmetric rolling process. This result indicates with certainty that the texture gradient and orientation inhomogeneity can be attributed to non-uniform deformation, whereas the uniform orientation gradient in the thickness direction is explained by the increased number of shear bands obtained in the asymmetric rolling process.
基金funded by both the National Natural Science Foundation of China(50734002)CITIC-CBMM R&D Subject Foundation (2010-D046).
文摘In order to understand the effect of the solidification structure on the formability of ultra low carbon ferritic stainless steel （FSS） ,this work studies the ridging phenomenon and the deep-drawing property in detail and the research method was X-ray diffraction （XRD） and scanning electron microscope （SEM） technique. The result shows that the columnar grain specimen had a higher ridging height than the equiaxed grain specimen, which was mainly attributed to the formation of grain colonies in the columnar grain specimen. After final recrystallization annealing, the equiaxed grain specimen obtained a high-intensity T-fiber texture and an excellent deep-drawing property.
基金supported by the Natural Science Foundation of Henan Province(252300421290)the National Natural Science Foundation of China(41771438)+1 种基金the Program for Innovative Research Team(in Science and Technology)of Henan University(22IRTSTHN010)the Postgraduate Education Reform and Quality Improvement Project of Henan Province(HNYJS2020JD14).
文摘Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient.This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation(ETC),Mann-Kendall test,Theil-Sen estimator,ridge regression analysis,and other relevant methods.The following findings were obtained:(1)at the pixel scale,the long-term monthly SM data from the European Space Agency Climate Change Initiative(ESA CCI)exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error(RMSE)of 0.014 m^(3)/m^(3);(2)from 2000 to 2022,the study area experienced significant increase in annual average SM,with a rate of 0.408×10^(-3)m^(3)/(m^(3)•a).Moreover,higher altitudes showed a notable upward trend,with SM increasing rates at 0.210×10^(-3)m^(3)/(m^(3)•a)between 1000 and 2000 m,0.530×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m,and 0.760×10^(-3)m^(3)/(m^(3)•a)at altitudes above 4000 m;(3)land surface temperature(LST),root zone soil moisture(RSM)(10-40 cm depth),and normalized difference vegetation index(NDVI)were identified as the primary factors influencing annual average SM,which accounted for 34.37%,24.16%,and 22.64%relative contributions,respectively;and(4)absolute contribution of LST was more significant in subareas at higher altitudes,with average absolute contributions of 0.800×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m and 0.500×10^(-2) m^(3)/(m^(3)•a)above 4000 m.This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas,highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas,providing valuable insights for ecological research and water resource management in these areas.
基金funded by Guizhou Provincial Science and Technology Project,Qiankehejichu-ZK[2022]-YB529Guizhou Education Department(Youth Science and Technology Topnotch Talent Project)QJJ[2024]345+1 种基金Guizhou Provincial Science and Technology Project,QKHJC-ZK[2023]-YBGuizhou Education Department Youth Science and Technology Talents Growth Project,QJHKY[2020]122.
文摘The complex and diverse nature of coal mining sites,including different landforms and working conditions,presents challenges for rehabilitation efforts.To address this,we conducted a comprehensive experimental study focusing on microbially induced calcium carbonate precipitation(MICP)remediation,considering the fracture characteristics of coal mining sites.The MICP-restored samples were subjected to confined/unconfined compressive strength,uniaxial/triaxial permeability,and souring tests to assess their restoration efficacy.The results showed that under similar mining conditions,the average depth of parallel fractures was 0.185 m for loess ridges,0.16 m for the valley,and 0.146 m for the blown-sand region,while the average depth for boundary fractures was 0.411 m for loess ridges,0.178 m for the valley,and 0.268 m for the blown-sand region.Notably,parallel fractures showed negligible filling in all landforms,whereas boundary fractures in the blown-sand region were completely filled with wind-deposited sand.The valley landform was filled with alluvium and wind-deposited sand,whereas the loess landform was filled with wind-deposited sand and loess.MICP-restored soil samples in all landforms achieved a strength comparable to remolded fracture-free soil samples.Across all landforms,the maximum permeability coefficient of MICP-restored soil samples closely matched that of remolded fracture-free soil samples.Under similar topographic and rainfall conditions MICP restorations scoured 31.3 g on blown-sand region,19.3 g on loess ridges,and 17.6 g on valleys.These research findings provide an experimental foundation for MICP repair of coal mining ground fractures.
基金funded by the National Natural Science Foundation of China under Grant 42230101the National Agency for Research and Development of Chile(ANID)by Projects AFB180004 and AFB220002the ANID Programa de Cooperación Internacional(PCI)Grant PII-180003.
文摘The Chilean Pampean flat slab subduction segment is characterized by the nearly horizontal subduction of the Nazca Plate within the depth range of 100-120 km.Numerous seismic tomography studies have been conducted to investigate its velocity structure;however,they have used only seismic body wave data or surface wave data.As a result,the existing velocity models in the region may have relatively large uncertainties.In this study,we use body wave arrival times from earthquakes occurring in central Chile between 2014 and 2019,as well as Rayleigh wave phase velocity maps at periods of 5-80 s from ambient noise empirical Green’s functions in Chile.By jointly using body wave arrival times and surface wave dispersion data,we refine the VS model and improve earthquake locations in the central Chile subduction zone.Compared with previous velocity models,our velocity model better reveals an eastward-dipping high-velocity plate representing the subducting Nazca Plate,which is 40-50 km thick and is more consistent with the slab thickness estimated by receiver function imaging and thermal modeling.Overall,the intraslab seismicity distribution spatially correlates well with the slab high-velocity anomalies except along the subduction paths of the CopiapóRidge and Juan Fernández Ridge.Additionally,parallel low-velocity stripes are imaged beneath the subducting plate,which are likely associated with the accumulated melts.The joint inversion velocity model also resolves widespread low-velocity anomalies in the crust beneath the Central Volcanic Zone of the central Andes,likely representing crustal magma chambers for various volcanoes.
基金supported by the National Key Research and Development Program of China(No.2022YFE03170003)the National Natural Science Foundation of China(Nos.12305403 and 12275243).
文摘β-ray-induced X-ray spectroscopy(BIXS)is a promising method for tritium detection in solid materials because of its unique advantages,such as large detection depth,nondestructive testing capabilities,and low requirements for sample preparation.However,high-accuracy reconstruction of the tritium depth profile remains a significant challenge for this technique.In this study,a novel reconstruction method based on a backpropagation(BP)neural network algorithm that demonstrates high accuracy,broad applicability,and robust noise resistance is proposed.The average reconstruction error calculated using the BP network(8.0%)was much lower than that obtained using traditional numerical methods(26.5%).In addition,the BP method can accurately reconstruct BIX spectra of samples with an unknown range of tritium and exhibits wide applicability to spectra with various tritium distributions.Furthermore,the BP network demonstrates superior accuracy and stability compared to numerical methods when reconstructing the spectra,with a relative uncertainty ranging from 0 to 10%.This study highlights the advantages of BP networks in accurately reconstructing the tritium depth profile from BIXS and promotes their further application in tritium detection.
基金Supported by the National Science and Technology Special Project of China(No.2017ZX05009-002)the China Scholarship Council(No.202106400055)。
文摘Palaeowind regime is an important component for reconstructing palaeoclimate and understanding ancient global circulation.We applied the beach-ridge thickness technique(BTT)and the longshore-bar thickness technique(LTT)to reconstruct the Early Cretaceous palaeowind velocities based on depositional records of Tanan Depression in Northeast Asia.The thickness of beach ridges and nearshore bars is the most important parameter for applying the BTT and the LTT methods.We identified 22 beach ridges and 23 nearshore bars based on drilling cores and wireline-log data in the Tanan Depression.Palaeowind velocities calculated by using the LTT method ranged from 10.84 to 13.66 m/s,showing a narrower range than those calculated by using the BTT method(7.58–15.93 m/s).We further analyzed the underlying factors causing the difference between the results derived from these two methods based on the sedimentary process of the beach ridge and the nearshore bar.The reconstructed wind regime was assumed to be the summer monsoon originating from the Mongol-Okhotsk Ocean before it had been completely enclosed,which provides valuable insight into the understanding of the atmospheric circulation in Northeast Asia during the Early Cretaceous.
基金financially supported by the Geological Survey of China(Grant Nos.DD20240075,and DD20243516)the National Natural Science Foundation of China(Grant No.41872209)Basic Scientific Research Fund of the Institute of Geology,Chinese Academy of Geological Sciences(Grant No.J2314)。
文摘We report new SHRIMP zircon U-Pb ages,zircon Lu-Hf isotopic and whole rock geochemical data from Permian granitoids located in the Alxa area of Inner Mongolia,China.In combination with published geochronological and geochemical data,the granitoids in the region can be divided into two age groups:ca.285 Ma and ca.269 Ma.The granitoids of the first group are mainly composed of calc-alkaline to high-K calc-alkaline,weakly peraluminous Ⅰ-type granodiorites with ε_(Hf)(t)values of-19.6 to-4.3,which demonstrates evidence of crustal reworking;the granitoids of the second group,however,mainly consist of A-type granites that are high-K calc-alkaline to shoshonite,metaluminous to weakly peraluminous,and have high 10,000×Ga/Al ratios(2.59-3.12)and ε_(Hf)(t)values ranging from-11.3 to-2.7,all of which demonstrates a mixed crust-mantle source.We interpret the granitoids of the first group to have formed during the subduction of Central Asian oceanic crust and the second group to have formed by the asthenospheric upwelling caused by the formation of slab windows during late ocean ridge subduction.
基金Foundation of China under Grant Nos. U2139207 and 52378517the Natural Science Foundation of Hubei Province under Grant No. 2023AFB934
文摘Seismic fault rupture can extend to the surface,and the resulting surface deformation can cause severe damage to civil engineering structures crossing the fault zones.Coseismic Surface Rupture Prediction Models(CSRPMs)play a crucial role in the structural design of fault-crossing engineering and in the hazard analysis of fault-intensive areas.In this study,a new global coseismic surface rupture database was constructed by compiling 171 earthquake events(Mw:5.5-7.9)that caused surface rupture.In contrast to the fault classification in traditional empirical relationships,this study categorizes earthquake events as strike-slip,dip-slip,and oblique-slip.CSRPMs utilizing Bayesian ridge regression(BRR)were developed to estimate parameters such as surface rupture length,average displacement,and maximum displacement.Based on Bayesian theory,BRR combines the benefits of both ridge regression and Bayesian linear regression.This approach effectively addresses the issue of overfitting while ensuring the strong model robustness.The reliability of the CSRPMs was validated by residual analysis and comparison with post-earthquake observations from the 2023 Türkiye earthquake doublet.The BRR-CSRPMs with new fault classification criteria are more suitable for the probabilistic hazard analysis of complex fault systems and dislocation design of fault-crossing engineering.
基金Supported by the Science and Technology Development Foundation of South China Sea Bureau,Ministry of Natural Resources,China(No.230204)the National Program on Global Change and Air-Sea Interaction(No.GASI-02-IND-CJ04)+1 种基金the Natural Science Foundation of Guangdong Province,China(No.2021A1515012589)the Key Technologies Research and Development Program of Guangzhou,Guangdong Province,China(No.2023B03J1379)。
文摘The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.
基金This work was supported by the Youth Project of Hunan Provincial Department of Education(Grant No.22B0334)the Bridge and Tunnel Engineering Innovation Project of Changsha University of Science&Technology(Grant No.11ZDXK11)and the Practical Innovation and Entrepreneurship Capacity Improvement Plan of Changsha University of Science and Technology(Grant No.CLSJCX23029).
文摘Organisms have evolved a strain limiting mechanism,reflected as a non-linear elastic constitutive,to prevent large deformations from threatening soft tissue integrity.Compared with linear elastic substrates,the wrinkle of films on non-linear elastic substrates has received less attention.In this article,a unique wrinkle evolution of the film-substrate system with a J-shaped non-linear stress-strain relation is reported.The result shows that a concave hexagonal array pattern is formed with the shrinkage strain of the film-substrate systems developing.As the interconnection of hexagonal arrays,a unit cell ridge network appears with properties such as chirality and helix.The subparagraph maze pattern formed with high compression is mainly composed of special single-cell ridge networks such as spiral single cores,chiral double cores,and combined multi-cores.This evolutionary model is highly consistent with the results of experiments,and it also predicts wrinkle morphology that has not yet been reported.These findings can serve as a novel explanation for the surface wrinkle of biological soft tissue,as well as provide references for the preparation of artificial biomaterials and programmable soft matter.
基金supported by the National Natural Science Foundation of China(Nos.42376071,42006056)the Special Fund of South China Sea Institute of Oceanol-ogy of the Chinese Academy of Sciences(No.SCSIO 2024QY02)the Chinese Academy of Sciences Pro-ject(No.Y4SL021).
文摘The Equatorial Atlantic Ocean,a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics,remains the focus of extensive research aimed at unraveling its evolution.However,its complex structural setting and contentious formation timeline have posed significant challenges.Through a comprehensive review of contemporary scientific litera-ture,we have identified three distinct phases for its evolution:pre-breakup,syn-breakup,and post-breakup,providing more detailed in-sights into the tectonic evolution of the Equatorial Atlantic.Prior to 110 Myr,the African and South American Plates underwent stretching predominantly from North to South,with the emergence of the Parana plume.This condition has led to the formation of nu-merous fracture zones and a triple junction.During the syn-breakup phase,spanning from 110 Myr to 90 Myr,the central region of the Equatorial Atlantic fully opened up,establishing a connection between the northern and southern waterways.However,the develop-ment of multiple ridge segments separated by numerous fracture zones in the central Equatorial Atlantic exhibited considerable com-plexity.The underlying causes for these complex structural formations remain elusive.Following the Chicxulub meteorite impact around 66 Myr and the emergence of the Sierra Leone hotspot,a pair of oceanic plateau‘twins’and a series of seamount chains were formed as a result of mantle plume tails.Consequently,the timeline of the Equatorial Atlantic’s tectonic evolution has gradually be-come clearer.However,due to the extensive timescale and the multitude of events involved in its formation,disputes about the precise-timing of various events still remain.The evolution of the Equatorial Atlantic has witnessed numerous ridge propagations,hotspot formations,and meteorite impacts,highlighting the need for further investigation into their interactions.The absence of identified magnetic isochrons in the Equatorial region emphasizes the urgency of additional exploration and analysis of its geological and geo-physical data.
