It is difficult to recover chrysocolla from sulfidation flotation which is closely related to the mineral surface composition.In this study,the effects of fluoride roasting on the surface composition of chrysocolla we...It is difficult to recover chrysocolla from sulfidation flotation which is closely related to the mineral surface composition.In this study,the effects of fluoride roasting on the surface composition of chrysocolla were investigated,its impact on sulfidation flotation was explored,and the mechanisms involved in both fluoride roasting and sulfidation flotation were discussed.With CaF_(2)as the roasting reagent,Na_(2)S·9H_(2)O as the sulfidation reagent,and sodium butyl xanthate(NaBX)as the collector,the results of the flotation experiments showed that fluoride roasting improved the floatability of chrysocolla,and the recovery rate increased from 16.87%to 82.74%.X-ray diffraction analysis revealed that after fluoride roasting,approximately all the Cu on the chrysocolla surface was exposed in the form of CuO,which could provide a basis for subsequent sulfidation flotation.The microscopy and elemental analyses revealed that large quantities of"pagoda-like"grains were observed on the sulfidation surface of the fluoride-roasted chrysocolla,indicating high crystallinity particles of copper sulfide.This suggests that the effect of sulfide formation on the chrysocolla surface was more pronounced.X-ray photoelectron spectroscopy revealed that fluoride roasting increased the relative contents of sulfur and copper on the surface and that both the Cu~+and polysulfide fractions on the surface of the minerals increased.This enhances the effect of sulfidation,which is conducive to flotation recovery.Therefore,fluoride roasting improved the effect of copper species transformation and sulfidation on the surface of chysocolla,promoted the adsorption of collectors,and improved the recovery of chrysocolla from sulfidation flotation.展开更多
The moment a media delegation from the Republic of the Congo arrived at the Othello Kitchenware Museum on 18 November 2025,they were greeted with a vivid show of Guangdong’s industrial strength.Standing before them w...The moment a media delegation from the Republic of the Congo arrived at the Othello Kitchenware Museum on 18 November 2025,they were greeted with a vivid show of Guangdong’s industrial strength.Standing before them was not a typical exhibition hall,but a building shaped like a gleaming stainless-steel cooking pot.展开更多
In the context of the digital transformation of vocational education,a quality evaluation index system has been constructed.Based on a questionnaire survey conducted among higher vocational colleges and enterprises in...In the context of the digital transformation of vocational education,a quality evaluation index system has been constructed.Based on a questionnaire survey conducted among higher vocational colleges and enterprises in Hainan Province,it has been found that the quality of vocational education generally depends on the talent training program and professional construction at the macro level.At the meso level,the teacher level and teaching environment are critical,while at the micro level,the evaluation of talent training quality cannot be underestimated.Strategies for quality improvement in vocational education are proposed from the perspectives of talent training programs,major construction,teacher development,teaching environment,and talent training quality,all under the lens of digital transformation.展开更多
Theβsolidifiedγ-TiAl alloy holds important application value in the aerospace industry,while its com-plex phase compositions and geometric structures pose challenges to its microstructure control during the thermal-...Theβsolidifiedγ-TiAl alloy holds important application value in the aerospace industry,while its com-plex phase compositions and geometric structures pose challenges to its microstructure control during the thermal-mechanical process.The microstructure evolution of Ti-43Al-4Nb-1Mo-0.2B alloy at 1200℃/0.01 s−1 was investigated to clarify the coupling role of dynamic recrystallization(DRX)and phase transformation.The results revealed that the rate of DRX inα2+γlamellar colonies was comparatively slower than that inβo+γmixed structure,instead being accompanied by intense lamellar kinking and rotation.The initiation and development rates of DRX inα2,βo,andγphases decreased sequentially.The asynchronous DRX of the various geometric structures and phase compositions resulted in the un-even deformed microstructure,and the dynamic softening induced by lamellar kinking and rotation was replaced by strengthened DRX as strain increased.Additionally,the blockyα2 phase and the terminals ofα2 lamellae were the preferential DRX sites owing to the abundant activated slip systems.Theα2→βo transformation within lamellar colonies facilitated DRX and fragment ofα2 lamellae,while theα2→γtransformation promoted the decomposition ofα2 lamellae and DRX ofγlamellae.Moreover,the var-iedβo+γmixed structures underwent complicated evolution:(1)Theγ→βo transformation occurred at boundaries of lamellar colonies,followed by simultaneous DRX ofγlamellar terminals and neighboringβo phase;(2)DRX occurred earlier within the band-likeβo phase,with the delayed DRX in enclosedγphase;(3)DRX within theβo synapses and neighboringγphase was accelerated owing to generation of elastic stress field;(4)Dispersedβo particles triggered particle stimulated nucleation(PSN)ofγphase.Eventually,atomic diffusion along crystal defects inβo andγphases caused fracture of band-likeβo phase and formation of massiveβo particles,impeding grain boundary migration and hindering DRXed grain growth ofγphase.展开更多
Agrobacterium tumefaciens-mediated transformation has been widely adopted for plant genetic engineering and the study of gene function(Krenek et al.,2015).This method is prevalent in the genetic transformation of herb...Agrobacterium tumefaciens-mediated transformation has been widely adopted for plant genetic engineering and the study of gene function(Krenek et al.,2015).This method is prevalent in the genetic transformation of herbaceous plants,with notable applications in species such as Arabidopsis(Yin et al.,2024),soybean(Zhang et al.,2024),rice(Zhang et al.,2020),and Chinese cabbage(Li et al.,2021).However,its application in fruit trees is limited.This is primarily due to their long growth cycles and lack of rapid,efficient,and stable transgenic systems,which severely hinders foundational research involving plant genetic transformation(Mei et al.,2024).Furthermore,for subtropical fruit trees,the presence of recalcitrant seeds adds an extra layer of difficulty to genetic transformation(Umarani et al.,2015),as most methods rely on seed germination as a basis for transformation.展开更多
The transformation from multibody models to lumped-parameter models is a crucial aspect of vehicle dynamics research.The velocity transformation method is adopted in this research,and the suspension multibody model is...The transformation from multibody models to lumped-parameter models is a crucial aspect of vehicle dynamics research.The velocity transformation method is adopted in this research,and the suspension multibody model is described using only one degree of freedom.It is found that the equivalent mass of the system is time-dependent during the simulation process,as observed in numerical simulations.Further symbolic calculations are conducted to derive the analytical form of the equivalent mass,and the results show that once the static parameters are determined,the equivalent mass of the suspension system is determined solely by the vertical position of the suspension upright,which reveals the kinematics characteristic of the equivalent mass of the suspension system.It is found that the equivalent mass experiences smaller changes when the suspension is compressed from the middle position,but larger changes when the suspension is extended.Furthermore,by comparing the multibody model,the lumped-parameter model with static mass,and the proposed lumped-parameter model considering the kinematics characteristic of the equivalent unsprung mass,the proposed model produces simulation results that more closely match the original multibody model than the model with static mass.The improvements in accuracy can be up to 20%under certain evaluation metrics.展开更多
This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that ...This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without Co.Moreover,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to 0.6.The improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant pair.Furthermore,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant pair.These findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52374259)the Open Fund of the State Key Laboratory of Mineral Processing Science and Technology,China(No.BGRIMM-KJSKL-2023-11)the Major Science and Technology Projects in Yunnan Province,China(No.202302 AF080004)。
文摘It is difficult to recover chrysocolla from sulfidation flotation which is closely related to the mineral surface composition.In this study,the effects of fluoride roasting on the surface composition of chrysocolla were investigated,its impact on sulfidation flotation was explored,and the mechanisms involved in both fluoride roasting and sulfidation flotation were discussed.With CaF_(2)as the roasting reagent,Na_(2)S·9H_(2)O as the sulfidation reagent,and sodium butyl xanthate(NaBX)as the collector,the results of the flotation experiments showed that fluoride roasting improved the floatability of chrysocolla,and the recovery rate increased from 16.87%to 82.74%.X-ray diffraction analysis revealed that after fluoride roasting,approximately all the Cu on the chrysocolla surface was exposed in the form of CuO,which could provide a basis for subsequent sulfidation flotation.The microscopy and elemental analyses revealed that large quantities of"pagoda-like"grains were observed on the sulfidation surface of the fluoride-roasted chrysocolla,indicating high crystallinity particles of copper sulfide.This suggests that the effect of sulfide formation on the chrysocolla surface was more pronounced.X-ray photoelectron spectroscopy revealed that fluoride roasting increased the relative contents of sulfur and copper on the surface and that both the Cu~+and polysulfide fractions on the surface of the minerals increased.This enhances the effect of sulfidation,which is conducive to flotation recovery.Therefore,fluoride roasting improved the effect of copper species transformation and sulfidation on the surface of chysocolla,promoted the adsorption of collectors,and improved the recovery of chrysocolla from sulfidation flotation.
文摘The moment a media delegation from the Republic of the Congo arrived at the Othello Kitchenware Museum on 18 November 2025,they were greeted with a vivid show of Guangdong’s industrial strength.Standing before them was not a typical exhibition hall,but a building shaped like a gleaming stainless-steel cooking pot.
文摘In the context of the digital transformation of vocational education,a quality evaluation index system has been constructed.Based on a questionnaire survey conducted among higher vocational colleges and enterprises in Hainan Province,it has been found that the quality of vocational education generally depends on the talent training program and professional construction at the macro level.At the meso level,the teacher level and teaching environment are critical,while at the micro level,the evaluation of talent training quality cannot be underestimated.Strategies for quality improvement in vocational education are proposed from the perspectives of talent training programs,major construction,teacher development,teaching environment,and talent training quality,all under the lens of digital transformation.
基金financially supported by the National Key Re-search and Development Program of China(No.2021YFB3702604)the National Natural Science Foundation of China(No.52174377)+1 种基金the Chongqing Natural Science Foundation Project(No.CSTB2023NSCQ-MSX0824)This work was also supported by the Shaanxi Materials Analysis&Research Center and the Analytical&Testing Center of NPU.
文摘Theβsolidifiedγ-TiAl alloy holds important application value in the aerospace industry,while its com-plex phase compositions and geometric structures pose challenges to its microstructure control during the thermal-mechanical process.The microstructure evolution of Ti-43Al-4Nb-1Mo-0.2B alloy at 1200℃/0.01 s−1 was investigated to clarify the coupling role of dynamic recrystallization(DRX)and phase transformation.The results revealed that the rate of DRX inα2+γlamellar colonies was comparatively slower than that inβo+γmixed structure,instead being accompanied by intense lamellar kinking and rotation.The initiation and development rates of DRX inα2,βo,andγphases decreased sequentially.The asynchronous DRX of the various geometric structures and phase compositions resulted in the un-even deformed microstructure,and the dynamic softening induced by lamellar kinking and rotation was replaced by strengthened DRX as strain increased.Additionally,the blockyα2 phase and the terminals ofα2 lamellae were the preferential DRX sites owing to the abundant activated slip systems.Theα2→βo transformation within lamellar colonies facilitated DRX and fragment ofα2 lamellae,while theα2→γtransformation promoted the decomposition ofα2 lamellae and DRX ofγlamellae.Moreover,the var-iedβo+γmixed structures underwent complicated evolution:(1)Theγ→βo transformation occurred at boundaries of lamellar colonies,followed by simultaneous DRX ofγlamellar terminals and neighboringβo phase;(2)DRX occurred earlier within the band-likeβo phase,with the delayed DRX in enclosedγphase;(3)DRX within theβo synapses and neighboringγphase was accelerated owing to generation of elastic stress field;(4)Dispersedβo particles triggered particle stimulated nucleation(PSN)ofγphase.Eventually,atomic diffusion along crystal defects inβo andγphases caused fracture of band-likeβo phase and formation of massiveβo particles,impeding grain boundary migration and hindering DRXed grain growth ofγphase.
基金funded by the Key-Area Research and Development Program of Guangdong Province(Grant No.2022B0202070002)the Guangxi Science and Technology Major Program(Grant No.GuikeAA23023007-2)+1 种基金the Guangdong Province Modern Agricultural Industry Technology System Innovation Team Construction Project(2024CXTD19)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515010303)。
文摘Agrobacterium tumefaciens-mediated transformation has been widely adopted for plant genetic engineering and the study of gene function(Krenek et al.,2015).This method is prevalent in the genetic transformation of herbaceous plants,with notable applications in species such as Arabidopsis(Yin et al.,2024),soybean(Zhang et al.,2024),rice(Zhang et al.,2020),and Chinese cabbage(Li et al.,2021).However,its application in fruit trees is limited.This is primarily due to their long growth cycles and lack of rapid,efficient,and stable transgenic systems,which severely hinders foundational research involving plant genetic transformation(Mei et al.,2024).Furthermore,for subtropical fruit trees,the presence of recalcitrant seeds adds an extra layer of difficulty to genetic transformation(Umarani et al.,2015),as most methods rely on seed germination as a basis for transformation.
基金This work was supported by the National Natural Science Foundation of China(Grant No.12272141)The financial support is gratefully acknowledged.
文摘The transformation from multibody models to lumped-parameter models is a crucial aspect of vehicle dynamics research.The velocity transformation method is adopted in this research,and the suspension multibody model is described using only one degree of freedom.It is found that the equivalent mass of the system is time-dependent during the simulation process,as observed in numerical simulations.Further symbolic calculations are conducted to derive the analytical form of the equivalent mass,and the results show that once the static parameters are determined,the equivalent mass of the suspension system is determined solely by the vertical position of the suspension upright,which reveals the kinematics characteristic of the equivalent mass of the suspension system.It is found that the equivalent mass experiences smaller changes when the suspension is compressed from the middle position,but larger changes when the suspension is extended.Furthermore,by comparing the multibody model,the lumped-parameter model with static mass,and the proposed lumped-parameter model considering the kinematics characteristic of the equivalent unsprung mass,the proposed model produces simulation results that more closely match the original multibody model than the model with static mass.The improvements in accuracy can be up to 20%under certain evaluation metrics.
基金supported by the National Natural Science Foundation of China(No.52271089)the financial support from the C hina Postdoctoral Science Foundation(No.2023M732192)。
文摘This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without Co.Moreover,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to 0.6.The improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant pair.Furthermore,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant pair.These findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.
