The viscosity of refining slags plays a critical role in metallurgical processes.However,obtaining accurate viscosity data remains challenging due to the complexities of high-temperature experiments,often relying on e...The viscosity of refining slags plays a critical role in metallurgical processes.However,obtaining accurate viscosity data remains challenging due to the complexities of high-temperature experiments,often relying on empirical models with limited predictive capabilities.This study focuses on the influence of optical basicity on viscosity in CaO-Al_(2)O_(3)-based refining slags,leveraging machine learning to address data scarcity and improve prediction accuracy.An automated framework for algorithm integration,parameter tuning,and evaluation ranking framework(Auto-APE)is employed to develop customized data-driven models for various slag systems,including CaO-Al_(2)O_(3)-SiO_(2),CaO-Al_(2)O_(3)-CaF_(2),CaO-Al_(2)O_(3)-SiO_(2)-MgO,and CaO-Al_(2)O_(3)-SiO_(2)-MgO-CaF_(2).By incorporating optical basicity as a key feature,the models achieve an average validation error of 8.0%to 15.1%,significantly outperforming traditional empirical models.Additionally,symbolic regression is introduced to rapidly construct domain-specific features,such as optical basicity-like descriptors,offering a potential breakthrough in performance prediction for small datasets.This work highlights the critical role of domain-specific knowledge in understanding and predicting viscosity,providing a robust machine learning-based approach for optimizing refining slag properties.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
A 3D mathematical model was established to investigate the gas-liquid two-phase flow in Ruhrstahl-Heraeus(RH)vacuum refining process.The flow characteristics of molten steel were calculated using the coupled standard...A 3D mathematical model was established to investigate the gas-liquid two-phase flow in Ruhrstahl-Heraeus(RH)vacuum refining process.The flow characteristics of molten steel were calculated using the coupled standard k-εmodel and volume of fluid model.The bubble distribution was tracked by discrete phase model.Electromagnetic field was applied in the up-leg snorkel to enhance the effect of vacuum refining.The effect of swirling flow nozzles combined with electromagnetic stirring(EMS)on the flow characteristics of molten steel and bubble distribution was analyzed.The erosion of the up-leg snorkel was compared.The results show that when the swirling flow nozzles are used,the bubbles exhibit a distinct adherent rising behavior,and the refining efficiency decreases.In addition,the electromagnetic field can significantly improve the refining efficiency,but it brings stronger erosion to the up-leg snorkel.Nevertheless,when using the swirling flow nozzles combined with EMS,the refining performance is further optimized,and the erosion of the up-leg snorkel is also reduced due to its characteristic of bubble distribution.Compared to conventional nozzles,the mixing time was shortened by 16.2%,the recirculation rate increased by 12.5%.and the swirling intensity was strengthened by 8.9%.展开更多
The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(...The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers.展开更多
Herein,the effect of direct current(DC)attached the mold on refining the microstructure and alleviating the central segregation of a tin–bismuth(Sn–10 wt.%Bi)alloy ingot during the solidification process has been in...Herein,the effect of direct current(DC)attached the mold on refining the microstructure and alleviating the central segregation of a tin–bismuth(Sn–10 wt.%Bi)alloy ingot during the solidification process has been investigated.The experiment used a self-made device,which can achieve the effect of refining the solidified structure and alleviate the segregation of the metal casting.Numerical simulations were performed to calculate the Lorentz force,Joule heating and induced melt vortex flow for the magneto-hydrodynamic case.Our results show that the maximum velocity of the global electro-vortex reached 0.017 m s^(–1).The DC-induced electro-vortex was found to be the primary reason of refining the equiaxed grain and alleviating the segregation of theβ-Sn crystal boundary.The grain refining effect observed in these experiments can be solely attributed to the forced melt flow driven by the Lorentz force.DC field attached the mold can lead to grain refinement and alleviate the segregation of the ingot via a global vortex.The technology can be applied not only to opened molds,but also toward improving the quality in closed molds.展开更多
High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.Hi...High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9.展开更多
1 The need to refine journal subject classification systems Journal subject classification systems are fundamental to journal evaluation,research assessments and information retrieval.Previous studies(e.g.,Wang&Wa...1 The need to refine journal subject classification systems Journal subject classification systems are fundamental to journal evaluation,research assessments and information retrieval.Previous studies(e.g.,Wang&Waltman,2016)have identified accuracy issues in major classification systems such as the Subject Categories in the Web of Science and ASJC in Scopus.展开更多
Slagging and calcium treatment are commonly used methods to control cleanliness and inclusions in steel.However,the inappropriate slagging and calcium treatment operations resulted in the generation of large-sized inc...Slagging and calcium treatment are commonly used methods to control cleanliness and inclusions in steel.However,the inappropriate slagging and calcium treatment operations resulted in the generation of large-sized inclusions and deterioration of steel cleanliness;meanwhile,changed inclusions from Al_(2)O_(3)–SiO_(2)–MnO type to Al_(2)O_(3)–SiO_(2)–CaO type after the calcium treatment during the production of an H-beam steel.Combining the thermodynamic analysis and industrial trials,measurements including reducing the basicity of refining slag to be less than 2.0 and the Al_(2)O_(3)content in slag to be less than 10 wt.%and the cancelation of calcium treatment under the total content less than 15×10^(−6)have been taken.After optimization,the content of total oxygen in tundish decreased by 24%;meanwhile,inclusions were changed from the Al_(2)O_(3)–SiO_(2)–CaO system to the Al_(2)O_(3)–SiO_(2)–MnO system with a low-melting point and a obvious decrease in the number density,area fraction,and maximum size of inclusions.It has achieved the improvement of steel cleanliness while reducing production costs.展开更多
Low-density short-duration pulsed current-assisted aging treatment was applied to the Ti-6Al-4V-0.5Mo-0.5Zr alloy subjected to different solution treatments.The results show that numerous α_(p) phases redissolve into...Low-density short-duration pulsed current-assisted aging treatment was applied to the Ti-6Al-4V-0.5Mo-0.5Zr alloy subjected to different solution treatments.The results show that numerous α_(p) phases redissolve into the new β phase during the pulsed current-assisted aging process,and then the newly formed β phase is mainly transformed into the β_(t) phase,with occasional transition to new α_(p) phase,leading to a remarkable grain refinement,especially for the lamellarαs phases.In comparison to conventional aging treatment,the pulsed current-assisted aging approach achieves a significant enhancement in strength without degrading ductility,yielding an excellent mechanical property combination:a yield strength of 932 MPa,a tensile strength of 1042 MPa,and an elongation of 12.2%.It is primarily ascribed to the increased fraction of β_(t) phases,the obvious grain refinement effect,and the slip block effect induced by the multiple-variantαs colonies distributed within β_(t) phases.展开更多
The effect of trace addition of 0.1wt%Y on the grain refinement and mechanical properties of Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc alloys at as-cast and heat-treated states was investigated.Results show that the additi...The effect of trace addition of 0.1wt%Y on the grain refinement and mechanical properties of Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc alloys at as-cast and heat-treated states was investigated.Results show that the addition of 0.1wt%Y into the Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc alloys can elevate the nucleation temperature of the Al_(3)(Sc,Zr)phase,leading to the preferential precipitation of the Al_(3)(Sc,Zr)phase and increasing the amount of Al_(3)(Sc,Zr)phase in the matrix.Al_(3)(Sc,Zr)phase can also act as a heterogeneous nucleation site in theα-Al matrix to promote nucleation and refine grains.The addition of element Y changes the precipitation phase characteristics at the grain boundaries in the as-cast alloy,which changes the distribution characteristics of secondary phases from initially continuous and coarse strip-like distribution at grain boundaries into the discontinuous dot-like and rod-like distribution.Besides,the size of secondary phases becomes smaller and their amount increases.Under the combined effects of grain refinement strengthening and precipitation strengthening,the Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc-0.1Y alloy after 175℃/10 h aging treatment achieves an ultimate tensile strength of 412 MPa and an elongation of 6.3%.Compared with those of the alloy without Y addition,the ultimate tensile strength and elongation of the added alloy increase by 16.1%and 53.7%,respectively.展开更多
At the start of the new year,Cao Xiucheng,Chairman of Henan No.2 Textile Machinery Co.,Ltd.,was on his way to visit clients when he kept receiving urgent calls from the Xinyang production base regarding order scheduli...At the start of the new year,Cao Xiucheng,Chairman of Henan No.2 Textile Machinery Co.,Ltd.,was on his way to visit clients when he kept receiving urgent calls from the Xinyang production base regarding order scheduling.It turned out that since the end of 2025,the company had successively secured bulk spindle orders from overseas clients in Bangladesh and other countries,coupled with continuous urgent requests for orders from domestic manufacturers.Faced with such a production peak right at the beginning of the year,Mr.Cao Xiucheng admitted,“It was truly unexpected.”展开更多
Semantic segmentation for mixed scenes of aerial remote sensing and road traffic is one of the key technologies for visual perception of flying cars.The State-of-the-Art(SOTA)semantic segmentation methods have made re...Semantic segmentation for mixed scenes of aerial remote sensing and road traffic is one of the key technologies for visual perception of flying cars.The State-of-the-Art(SOTA)semantic segmentation methods have made remarkable achievements in both fine-grained segmentation and real-time performance.However,when faced with the huge differences in scale and semantic categories brought about by the mixed scenes of aerial remote sensing and road traffic,they still face great challenges and there is little related research.Addressing the above issue,this paper proposes a semantic segmentation model specifically for mixed datasets of aerial remote sensing and road traffic scenes.First,a novel decoding-recoding multi-scale feature iterative refinement structure is proposed,which utilizes the re-integration and continuous enhancement of multi-scale information to effectively deal with the huge scale differences between cross-domain scenes,while using a fully convolutional structure to ensure the lightweight and real-time requirements.Second,a welldesigned cross-window attention mechanism combined with a global information integration decoding block forms an enhanced global context perception,which can effectively capture the long-range dependencies and multi-scale global context information of different scenes,thereby achieving fine-grained semantic segmentation.The proposed method is tested on a large-scale mixed dataset of aerial remote sensing and road traffic scenes.The results confirm that it can effectively deal with the problem of large-scale differences in cross-domain scenes.Its segmentation accuracy surpasses that of the SOTA methods,which meets the real-time requirements.展开更多
Salient object detection(SOD)models struggle to simultaneously preserve global structure,maintain sharp object boundaries,and sustain computational efficiency in complex scenes.In this study,we propose SPSALNet,a task...Salient object detection(SOD)models struggle to simultaneously preserve global structure,maintain sharp object boundaries,and sustain computational efficiency in complex scenes.In this study,we propose SPSALNet,a task-driven two-stage(macro–micro)architecture that restructures the SOD process around superpixel representations.In the proposed approach,a“split-and-enhance”principle,introduced to our knowledge for the first time in the SOD literature,hierarchically classifies superpixels and then applies targeted refinement only to ambiguous or error-prone regions.At the macro stage,the image is partitioned into content-adaptive superpixel regions,and each superpixel is represented by a high-dimensional region-level feature vector.These representations define a regional decomposition problem in which superpixels are assigned to three classes:background,object interior,and transition regions.Superpixel tokens interact with a global feature vector from a deep network backbone through a cross-attention module and are projected into an enriched embedding space that jointly encodes local topology and global context.At the micro stage,the model employs a U-Net-based refinement process that allocates computational resources only to ambiguous transition regions.The image and distance–similarity maps derived from superpixels are processed through a dual-encoder pathway.Subsequently,channel-aware fusion blocks adaptively combine information from these two sources,producing sharper and more stable object boundaries.Experimental results show that SPSALNet achieves high accuracy with lower computational cost compared to recent competing methods.On the PASCAL-S and DUT-OMRON datasets,SPSALNet exhibits a clear performance advantage across all key metrics,and it ranks first on accuracy-oriented measures on HKU-IS.On the challenging DUT-OMRON benchmark,SPSALNet reaches a MAE of 0.034.Across all datasets,it preserves object boundaries and regional structure in a stable and competitive manner.展开更多
The ultrasonic energy field(UEF)-induced grain refinement mechanisms in laser powder direct energy deposition-manufactured Ti5321G alloys were systematically investigated in this study.This study focused on the interp...The ultrasonic energy field(UEF)-induced grain refinement mechanisms in laser powder direct energy deposition-manufactured Ti5321G alloys were systematically investigated in this study.This study focused on the interplay between recrystallization in the high-temperature solid deposition layers and the ultrasonic cavitation-acoustic streaming effects during molten pool solidification.A novel experimental design was developed to decouple these mechanisms by creating four distinct UEF action zones(without UEF-N,withUEF-S,with UEF-L,and with UEF-S+L)within a single-pass multilayer sample.This approach enabled the dual effects of UEF(recrystallization in solidified layers and ultrasonic cavitation-acoustic streaming effects in liquid pools)to be directly compared.The UEF significantly refined the microstructures,reducing the average grain size by 64.2%(from(399.6±28.6)to(143.1±16.1)μm)in the with UEF-S+L zone,while promoting columnar-to-equiaxed transition,with the equiaxed grain probability increasing from 11.1%(without UEF) to 53.8%.The texture intensity was reduced by approximately 52.4%and the mechanical properties were enhanced,achieving a 6.2% increase in yield strength((702.0±10.6)MPa)and 31.7%improvement in elongation.Crucially,this study revealed the synergistic effect of the dual-action mechanisms of UEF,where recrystallization and cavitation-acoustic streaming collectively enabled non-linear grain refinement.This study provides a strategy for microstructural control in additive manufacturing,eliminating the need for complex post-processing and thereby advancing the industrial application of high-performance titanium components.展开更多
Continuous variable cross-section recycled extrusion(CVCE)is an advanced technique of severe plastic deformation.Ti–6Al–4V alloy was deformed with different processing parameters by CVCE,and then the microstructure ...Continuous variable cross-section recycled extrusion(CVCE)is an advanced technique of severe plastic deformation.Ti–6Al–4V alloy was deformed with different processing parameters by CVCE,and then the microstructure characterization,refinement mechanism and deformation mechanism were investigated simultaneously.The results demonstrate that the average size of grain is refined from 14 to 2.78μm as Ti–6Al–4V alloy is deformed at 800℃ with a speed of 2 mm/s over 6 passes,and the microstructure is equiaxed and distributed homogeneously along the radial direction.Furthermore,in the process of CVCE,basal slip(0001)<110>is transformed to prismatic slip(100)<110>system and pyramidal slip(112)<113>system,with a reduction in low angle grain boundaries from 69.6%to 61.2%.Moreover,the grain refinement mechanism of CVCE is dislocation multiplication and cross-slip migration within the grain at the initial stage of deformation,which results in the formation of substructures and micro-shear bands as well as grain refinement.In addition,the nucleation and growth of dynamic recrystallization grains are beneficial to eliminating the dislocations,subgrain boundaries and other defects in the matrix,which finally results in the grains refinement.展开更多
A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of ...A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of main components of crude lead,separation coefficients and vapor-liquid equilibrium composition of Pb-i（i stands for an impurity） system at different temperatures.The behaviors of impurities in the vacuum distillation refining process were investigated.The results show that the vacuum distillation should be taken to obtain lead from crude lead,in which Zn,As and partial Sb are volatilized at lower temperature of 923-1023 K.Lead is distilled from the residue containing Cu,Sn,Ag and Bi at higher temperature of 1323-1423 K,but the impurity Bi is also volatilized along with lead and cannot be separated from lead.展开更多
Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of...Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of CaO-SiO2 slag for boron removal was characterized by establishing the thermodynamic relationship between the distribution coefficient of boron （LB） and the activities of SiO2 and CaO. The experimental results show that the distribution coefficient and the removal efficiency of boron are greatly improved with the increase of CaO proportion in the slag. The maximal value of LB reaches 1.57 with a slag composition of 60%CaO-40%SiO2 （mass fraction）. The boron content in the refined silicon is reduced from 18×10^-6 to 1.8×10^-6 using slag refining at 1600 ℃ for 3 h with a CaO-SiO2/MG-Si ratio of 2.5, and the removal efficiency of boron reaches 90%.展开更多
The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimenta...The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimental results indicate that the iron content decreases with increasing Na2B4O7 addition and remelting time,and the iron content decreases from 0.400% to 0.184% under 9% Na2B4O7 addition for 30 min remelting.The elastic modulus,yield strength and ultimate tensile strength commercial aluminum are improved,and the tensile elongation is increased by 43% after electroslag refining.The chemical reaction between melt and slag to form Fe2B is the main reason for iron reduction and the thermodynamic calculation of the chemical reaction theoretically accounts for the formation of Fe2B.展开更多
In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a wat...In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a water model for pursuing better bubble disintegration and dispersion.Effects of various factors on bubble disintegration and dispersion were investigated.These factors were stirring mode,eccentricity and rotation speed,nozzle structure,nozzle immersion depth,and gas flow rate.Gas injection from a nozzle at the end of the impeller shaft and from an immersed lance was studied.Under eccentric stirring,a vortex was formed away from the shaft.Small bubbles were produced in the strong turbulence or high shear stress field near the rotating impeller and moved in the direction to the vortex keeping up with the macroscopic flow induced by the mechanical stirring.Thus small bubbles could disperse widely in the bath under eccentric stirring with unidirectional rotation.展开更多
Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of...Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of Al-7Si. It is found that the number and the settlement of AlB2 particles in the melt all have effect on the grain refining efficiency. On the basis of experiments and theoretical analysis, a new grain refinement mechanism was proposed to explain the grain refinement action of Al-3B on hypoeutectic Al-Si alloys. The formation of ＇Al-AlB2＇ shell structure is the direct reason for grain refinement and the undissolved AlB2 particles is the indirect nucleating base for subsequent α（Al） phase.展开更多
基金supported by the National Key Research and Development Program of China(No.2023YFB3712401),the National Natural Science Foundation of China(No.52274301)the Aeronautical Science Foundation of China(No.2023Z0530S6005)the Ningbo Yongjiang Talent-Introduction Programme(No.2022A-023-C).
文摘The viscosity of refining slags plays a critical role in metallurgical processes.However,obtaining accurate viscosity data remains challenging due to the complexities of high-temperature experiments,often relying on empirical models with limited predictive capabilities.This study focuses on the influence of optical basicity on viscosity in CaO-Al_(2)O_(3)-based refining slags,leveraging machine learning to address data scarcity and improve prediction accuracy.An automated framework for algorithm integration,parameter tuning,and evaluation ranking framework(Auto-APE)is employed to develop customized data-driven models for various slag systems,including CaO-Al_(2)O_(3)-SiO_(2),CaO-Al_(2)O_(3)-CaF_(2),CaO-Al_(2)O_(3)-SiO_(2)-MgO,and CaO-Al_(2)O_(3)-SiO_(2)-MgO-CaF_(2).By incorporating optical basicity as a key feature,the models achieve an average validation error of 8.0%to 15.1%,significantly outperforming traditional empirical models.Additionally,symbolic regression is introduced to rapidly construct domain-specific features,such as optical basicity-like descriptors,offering a potential breakthrough in performance prediction for small datasets.This work highlights the critical role of domain-specific knowledge in understanding and predicting viscosity,providing a robust machine learning-based approach for optimizing refining slag properties.
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.
基金support from the National Natural Science Foundation of China(No.52174305).
文摘A 3D mathematical model was established to investigate the gas-liquid two-phase flow in Ruhrstahl-Heraeus(RH)vacuum refining process.The flow characteristics of molten steel were calculated using the coupled standard k-εmodel and volume of fluid model.The bubble distribution was tracked by discrete phase model.Electromagnetic field was applied in the up-leg snorkel to enhance the effect of vacuum refining.The effect of swirling flow nozzles combined with electromagnetic stirring(EMS)on the flow characteristics of molten steel and bubble distribution was analyzed.The erosion of the up-leg snorkel was compared.The results show that when the swirling flow nozzles are used,the bubbles exhibit a distinct adherent rising behavior,and the refining efficiency decreases.In addition,the electromagnetic field can significantly improve the refining efficiency,but it brings stronger erosion to the up-leg snorkel.Nevertheless,when using the swirling flow nozzles combined with EMS,the refining performance is further optimized,and the erosion of the up-leg snorkel is also reduced due to its characteristic of bubble distribution.Compared to conventional nozzles,the mixing time was shortened by 16.2%,the recirculation rate increased by 12.5%.and the swirling intensity was strengthened by 8.9%.
基金support from the National Key R&D Program(No.2023YFB3709900)the National Natural Science Foundation of China(Grant No.U22A20171)+1 种基金the High Steel Center at the North China University of Technologythe University of Science and Technology Beijing,China.
文摘The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers.
基金the National Natural Science Foundation of China(51974155)the Outstanding Young Scientific and Technological Talents Project of University of Science and Technology Liaoning(2023YQ07)+4 种基金the University of Science and Technology Liaoning Young Foundation(2018QN06)National Natural Science Foundation of China(51774178)the National Key Research and Development Program(2021YFB3702005)the Central Government Guides Local Science and Technology Development Fund Projects(2023JH6/100100046)the Liaoning Provincial Department of Education Basic Research Projects for Universities(JYTQN2023242).
文摘Herein,the effect of direct current(DC)attached the mold on refining the microstructure and alleviating the central segregation of a tin–bismuth(Sn–10 wt.%Bi)alloy ingot during the solidification process has been investigated.The experiment used a self-made device,which can achieve the effect of refining the solidified structure and alleviate the segregation of the metal casting.Numerical simulations were performed to calculate the Lorentz force,Joule heating and induced melt vortex flow for the magneto-hydrodynamic case.Our results show that the maximum velocity of the global electro-vortex reached 0.017 m s^(–1).The DC-induced electro-vortex was found to be the primary reason of refining the equiaxed grain and alleviating the segregation of theβ-Sn crystal boundary.The grain refining effect observed in these experiments can be solely attributed to the forced melt flow driven by the Lorentz force.DC field attached the mold can lead to grain refinement and alleviate the segregation of the ingot via a global vortex.The technology can be applied not only to opened molds,but also toward improving the quality in closed molds.
基金National Key Research and Development Program of China(2023YFC2907904)National Natural Science Foundation of China(52374364)。
文摘High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9.
文摘1 The need to refine journal subject classification systems Journal subject classification systems are fundamental to journal evaluation,research assessments and information retrieval.Previous studies(e.g.,Wang&Waltman,2016)have identified accuracy issues in major classification systems such as the Subject Categories in the Web of Science and ASJC in Scopus.
基金support from the National Key R&D Program(Nos.2023YFB3506802 and 2023YFB3709900)the National Natural Science Foundation of China(Grant Nos.52174293 and U22A20171)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.FRF-BD-20-04A)the High Steel Center(HSC)at North China University of Technology.
文摘Slagging and calcium treatment are commonly used methods to control cleanliness and inclusions in steel.However,the inappropriate slagging and calcium treatment operations resulted in the generation of large-sized inclusions and deterioration of steel cleanliness;meanwhile,changed inclusions from Al_(2)O_(3)–SiO_(2)–MnO type to Al_(2)O_(3)–SiO_(2)–CaO type after the calcium treatment during the production of an H-beam steel.Combining the thermodynamic analysis and industrial trials,measurements including reducing the basicity of refining slag to be less than 2.0 and the Al_(2)O_(3)content in slag to be less than 10 wt.%and the cancelation of calcium treatment under the total content less than 15×10^(−6)have been taken.After optimization,the content of total oxygen in tundish decreased by 24%;meanwhile,inclusions were changed from the Al_(2)O_(3)–SiO_(2)–CaO system to the Al_(2)O_(3)–SiO_(2)–MnO system with a low-melting point and a obvious decrease in the number density,area fraction,and maximum size of inclusions.It has achieved the improvement of steel cleanliness while reducing production costs.
基金National Key Research and Development Program of China(2021YFB3700801)。
文摘Low-density short-duration pulsed current-assisted aging treatment was applied to the Ti-6Al-4V-0.5Mo-0.5Zr alloy subjected to different solution treatments.The results show that numerous α_(p) phases redissolve into the new β phase during the pulsed current-assisted aging process,and then the newly formed β phase is mainly transformed into the β_(t) phase,with occasional transition to new α_(p) phase,leading to a remarkable grain refinement,especially for the lamellarαs phases.In comparison to conventional aging treatment,the pulsed current-assisted aging approach achieves a significant enhancement in strength without degrading ductility,yielding an excellent mechanical property combination:a yield strength of 932 MPa,a tensile strength of 1042 MPa,and an elongation of 12.2%.It is primarily ascribed to the increased fraction of β_(t) phases,the obvious grain refinement effect,and the slip block effect induced by the multiple-variantαs colonies distributed within β_(t) phases.
基金National Natural Science Foundation of China(52071065)Fundamental Research Funds for the Central Universities(N2007007)+2 种基金Joint Fund of Henan Province Science and Technology R&D Program(N225200810040)High-Level Talent Research Start-Up Project Funding of Henan Academy of Sciences(N242017003)Liaoning Provincial Department of Education Basic Research Projects for Colleges and Universities(LJ212410142093)。
文摘The effect of trace addition of 0.1wt%Y on the grain refinement and mechanical properties of Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc alloys at as-cast and heat-treated states was investigated.Results show that the addition of 0.1wt%Y into the Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc alloys can elevate the nucleation temperature of the Al_(3)(Sc,Zr)phase,leading to the preferential precipitation of the Al_(3)(Sc,Zr)phase and increasing the amount of Al_(3)(Sc,Zr)phase in the matrix.Al_(3)(Sc,Zr)phase can also act as a heterogeneous nucleation site in theα-Al matrix to promote nucleation and refine grains.The addition of element Y changes the precipitation phase characteristics at the grain boundaries in the as-cast alloy,which changes the distribution characteristics of secondary phases from initially continuous and coarse strip-like distribution at grain boundaries into the discontinuous dot-like and rod-like distribution.Besides,the size of secondary phases becomes smaller and their amount increases.Under the combined effects of grain refinement strengthening and precipitation strengthening,the Al-2.2Li-1.5Cu-0.5Mg-1Zn-0.2Zr-0.2Sc-0.1Y alloy after 175℃/10 h aging treatment achieves an ultimate tensile strength of 412 MPa and an elongation of 6.3%.Compared with those of the alloy without Y addition,the ultimate tensile strength and elongation of the added alloy increase by 16.1%and 53.7%,respectively.
文摘At the start of the new year,Cao Xiucheng,Chairman of Henan No.2 Textile Machinery Co.,Ltd.,was on his way to visit clients when he kept receiving urgent calls from the Xinyang production base regarding order scheduling.It turned out that since the end of 2025,the company had successively secured bulk spindle orders from overseas clients in Bangladesh and other countries,coupled with continuous urgent requests for orders from domestic manufacturers.Faced with such a production peak right at the beginning of the year,Mr.Cao Xiucheng admitted,“It was truly unexpected.”
基金supported by the National Key Research and Development of China(No.2022YFB2503400).
文摘Semantic segmentation for mixed scenes of aerial remote sensing and road traffic is one of the key technologies for visual perception of flying cars.The State-of-the-Art(SOTA)semantic segmentation methods have made remarkable achievements in both fine-grained segmentation and real-time performance.However,when faced with the huge differences in scale and semantic categories brought about by the mixed scenes of aerial remote sensing and road traffic,they still face great challenges and there is little related research.Addressing the above issue,this paper proposes a semantic segmentation model specifically for mixed datasets of aerial remote sensing and road traffic scenes.First,a novel decoding-recoding multi-scale feature iterative refinement structure is proposed,which utilizes the re-integration and continuous enhancement of multi-scale information to effectively deal with the huge scale differences between cross-domain scenes,while using a fully convolutional structure to ensure the lightweight and real-time requirements.Second,a welldesigned cross-window attention mechanism combined with a global information integration decoding block forms an enhanced global context perception,which can effectively capture the long-range dependencies and multi-scale global context information of different scenes,thereby achieving fine-grained semantic segmentation.The proposed method is tested on a large-scale mixed dataset of aerial remote sensing and road traffic scenes.The results confirm that it can effectively deal with the problem of large-scale differences in cross-domain scenes.Its segmentation accuracy surpasses that of the SOTA methods,which meets the real-time requirements.
文摘Salient object detection(SOD)models struggle to simultaneously preserve global structure,maintain sharp object boundaries,and sustain computational efficiency in complex scenes.In this study,we propose SPSALNet,a task-driven two-stage(macro–micro)architecture that restructures the SOD process around superpixel representations.In the proposed approach,a“split-and-enhance”principle,introduced to our knowledge for the first time in the SOD literature,hierarchically classifies superpixels and then applies targeted refinement only to ambiguous or error-prone regions.At the macro stage,the image is partitioned into content-adaptive superpixel regions,and each superpixel is represented by a high-dimensional region-level feature vector.These representations define a regional decomposition problem in which superpixels are assigned to three classes:background,object interior,and transition regions.Superpixel tokens interact with a global feature vector from a deep network backbone through a cross-attention module and are projected into an enriched embedding space that jointly encodes local topology and global context.At the micro stage,the model employs a U-Net-based refinement process that allocates computational resources only to ambiguous transition regions.The image and distance–similarity maps derived from superpixels are processed through a dual-encoder pathway.Subsequently,channel-aware fusion blocks adaptively combine information from these two sources,producing sharper and more stable object boundaries.Experimental results show that SPSALNet achieves high accuracy with lower computational cost compared to recent competing methods.On the PASCAL-S and DUT-OMRON datasets,SPSALNet exhibits a clear performance advantage across all key metrics,and it ranks first on accuracy-oriented measures on HKU-IS.On the challenging DUT-OMRON benchmark,SPSALNet reaches a MAE of 0.034.Across all datasets,it preserves object boundaries and regional structure in a stable and competitive manner.
基金supported by the National Key Researchand Development Program of China(No.2021YFC2801904)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai,China(No.AMGM2024F11).
文摘The ultrasonic energy field(UEF)-induced grain refinement mechanisms in laser powder direct energy deposition-manufactured Ti5321G alloys were systematically investigated in this study.This study focused on the interplay between recrystallization in the high-temperature solid deposition layers and the ultrasonic cavitation-acoustic streaming effects during molten pool solidification.A novel experimental design was developed to decouple these mechanisms by creating four distinct UEF action zones(without UEF-N,withUEF-S,with UEF-L,and with UEF-S+L)within a single-pass multilayer sample.This approach enabled the dual effects of UEF(recrystallization in solidified layers and ultrasonic cavitation-acoustic streaming effects in liquid pools)to be directly compared.The UEF significantly refined the microstructures,reducing the average grain size by 64.2%(from(399.6±28.6)to(143.1±16.1)μm)in the with UEF-S+L zone,while promoting columnar-to-equiaxed transition,with the equiaxed grain probability increasing from 11.1%(without UEF) to 53.8%.The texture intensity was reduced by approximately 52.4%and the mechanical properties were enhanced,achieving a 6.2% increase in yield strength((702.0±10.6)MPa)and 31.7%improvement in elongation.Crucially,this study revealed the synergistic effect of the dual-action mechanisms of UEF,where recrystallization and cavitation-acoustic streaming collectively enabled non-linear grain refinement.This study provides a strategy for microstructural control in additive manufacturing,eliminating the need for complex post-processing and thereby advancing the industrial application of high-performance titanium components.
基金supported by the fund of National Natural Science Foundation of China(No.U25A20205)Xi'an Science and Technology Plan Program(No.24LLRHZDZX0008)+1 种基金Key R&D Project in Shaanxi Province(No.2024GX-YBXM-211)Xianyang Science and Technology Plan Program(No.L2025-ZDYF-GDZB-014).
文摘Continuous variable cross-section recycled extrusion(CVCE)is an advanced technique of severe plastic deformation.Ti–6Al–4V alloy was deformed with different processing parameters by CVCE,and then the microstructure characterization,refinement mechanism and deformation mechanism were investigated simultaneously.The results demonstrate that the average size of grain is refined from 14 to 2.78μm as Ti–6Al–4V alloy is deformed at 800℃ with a speed of 2 mm/s over 6 passes,and the microstructure is equiaxed and distributed homogeneously along the radial direction.Furthermore,in the process of CVCE,basal slip(0001)<110>is transformed to prismatic slip(100)<110>system and pyramidal slip(112)<113>system,with a reduction in low angle grain boundaries from 69.6%to 61.2%.Moreover,the grain refinement mechanism of CVCE is dislocation multiplication and cross-slip migration within the grain at the initial stage of deformation,which results in the formation of substructures and micro-shear bands as well as grain refinement.In addition,the nucleation and growth of dynamic recrystallization grains are beneficial to eliminating the dislocations,subgrain boundaries and other defects in the matrix,which finally results in the grains refinement.
基金Project (2012CB722803) supported by the National Basic Research Program of ChinaProject (U1202271) supported by the National Natural Science Foundation of China
文摘A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of main components of crude lead,separation coefficients and vapor-liquid equilibrium composition of Pb-i（i stands for an impurity） system at different temperatures.The behaviors of impurities in the vacuum distillation refining process were investigated.The results show that the vacuum distillation should be taken to obtain lead from crude lead,in which Zn,As and partial Sb are volatilized at lower temperature of 923-1023 K.Lead is distilled from the residue containing Cu,Sn,Ag and Bi at higher temperature of 1323-1423 K,but the impurity Bi is also volatilized along with lead and cannot be separated from lead.
基金Projects (51104080,u1137601) supported by the National Natural Science Foundation of ChinaProject (14118557) supported by the Personnel Training Foundation of Kunming University of Science and Technology in China
文摘Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of CaO-SiO2 slag for boron removal was characterized by establishing the thermodynamic relationship between the distribution coefficient of boron （LB） and the activities of SiO2 and CaO. The experimental results show that the distribution coefficient and the removal efficiency of boron are greatly improved with the increase of CaO proportion in the slag. The maximal value of LB reaches 1.57 with a slag composition of 60%CaO-40%SiO2 （mass fraction）. The boron content in the refined silicon is reduced from 18×10^-6 to 1.8×10^-6 using slag refining at 1600 ℃ for 3 h with a CaO-SiO2/MG-Si ratio of 2.5, and the removal efficiency of boron reaches 90%.
基金Project (50825401) supported by the National Natural Science Foundation of ChinaProject (2012CB61905) supported by the National Basic Research Program of China
文摘The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimental results indicate that the iron content decreases with increasing Na2B4O7 addition and remelting time,and the iron content decreases from 0.400% to 0.184% under 9% Na2B4O7 addition for 30 min remelting.The elastic modulus,yield strength and ultimate tensile strength commercial aluminum are improved,and the tensile elongation is increased by 43% after electroslag refining.The chemical reaction between melt and slag to form Fe2B is the main reason for iron reduction and the thermodynamic calculation of the chemical reaction theoretically accounts for the formation of Fe2B.
基金Projects (50974035,51074047) supported by the National Natural Science Foundation of ChinaProject (20090407) supported by the Doctoral Fund of Ministry of Education,ChinaProject (200921007) supported by Liaoning Key Science and Technology,China
文摘In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a water model for pursuing better bubble disintegration and dispersion.Effects of various factors on bubble disintegration and dispersion were investigated.These factors were stirring mode,eccentricity and rotation speed,nozzle structure,nozzle immersion depth,and gas flow rate.Gas injection from a nozzle at the end of the impeller shaft and from an immersed lance was studied.Under eccentric stirring,a vortex was formed away from the shaft.Small bubbles were produced in the strong turbulence or high shear stress field near the rotating impeller and moved in the direction to the vortex keeping up with the macroscopic flow induced by the mechanical stirring.Thus small bubbles could disperse widely in the bath under eccentric stirring with unidirectional rotation.
基金Project supported by Tsinghua-Wuxi Science Foundation, China
文摘Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of Al-7Si. It is found that the number and the settlement of AlB2 particles in the melt all have effect on the grain refining efficiency. On the basis of experiments and theoretical analysis, a new grain refinement mechanism was proposed to explain the grain refinement action of Al-3B on hypoeutectic Al-Si alloys. The formation of ＇Al-AlB2＇ shell structure is the direct reason for grain refinement and the undissolved AlB2 particles is the indirect nucleating base for subsequent α（Al） phase.
