In order to reveal the effect of 2-hydroxy-3-naphthyl hydroxamic acid(H205)on the flotation behavior and action mechanism of bastnaesite,single-mineral flotation experiments of bastnaesite were conducted.The flotation...In order to reveal the effect of 2-hydroxy-3-naphthyl hydroxamic acid(H205)on the flotation behavior and action mechanism of bastnaesite,single-mineral flotation experiments of bastnaesite were conducted.The flotation recovery of bastnaesites can be achieved more than 90%when the aeration rate is 40 mL/min,the rotational speed is 200 r/min,the H205 dosage is 120 mg/L,and the pulp pH ranges from 7 to 9.The action mechanism of H205 on the surface of bastnaesite was studied by simultaneous thermogravimetry and differential scanning calorimetry(TG-DSC),Zeta potential measurements,Fourier transform-infrared spectra(FT-IR)and X-ray photoelectron spectroscopy(XPS).These analysis results show that under suitable flotation conditions,H205 has an obvious adsorption phenomenon on the surface of bastnaesite.The adsorption involves electrostatic interactions and chemical interactions,namely H205 has a strong collecting ability of bastnaesite due to the synergism of electrostatic adsorption and chemical adsorption.This study systematically reveals the flotation behavior and adsorption mechanism of H205 on the surface of bastnaesite,and provides useful theoretical guidance for efficient flotation separation of bastnaesite.展开更多
Neuromorphic devices have shown great potential in simulating the function of biological neurons due to their efficient parallel information processing and low energy consumption.MXene-Ti_(3)C_(2)T_(x),an emerging two...Neuromorphic devices have shown great potential in simulating the function of biological neurons due to their efficient parallel information processing and low energy consumption.MXene-Ti_(3)C_(2)T_(x),an emerging twodimensional material,stands out as an ideal candidate for fabricating neuromorphic devices.Its exceptional electrical performance and robust mechanical properties make it an ideal choice for this purpose.This review aims to uncover the advantages and properties of MXene-Ti_(3)C_(2)T_(x)in neuromorphic devices and to promote its further development.Firstly,we categorize several core physical mechanisms present in MXene-Ti_(3)C_(2)T_(x)neuromorphic devices and summarize in detail the reasons for their formation.Then,this work systematically summarizes and classifies advanced techniques for the three main optimization pathways of MXene-Ti_(3)C_(2)T_(x),such as doping engineering,interface engineering,and structural engineering.Significantly,this work highlights innovative applications of MXene-Ti_(3)C_(2)T_(x)neuromorphic devices in cutting-edge computing paradigms,particularly near-sensor computing and in-sensor computing.Finally,this review carefully compiles a table that integrates almost all research results involving MXene-Ti_(3)C_(2)T_(x)neuromorphic devices and discusses the challenges,development prospects,and feasibility of MXene-Ti_(3)C_(2)T_(x)-based neuromorphic devices in practical applications,aiming to lay a solid theoretical foundation and provide technical support for further exploration and application of MXene-Ti_(3)C_(2)T_(x)in the field of neuromorphic devices.展开更多
Nearly undamaged joints of electron beam welded(EBW)dual-phase Mg-8Li-3Al-2Zn-0.5Y alloy were achieved with joint coefficients exceeding 95%.All specimens were fractured at the base metal(BM),implying a significant de...Nearly undamaged joints of electron beam welded(EBW)dual-phase Mg-8Li-3Al-2Zn-0.5Y alloy were achieved with joint coefficients exceeding 95%.All specimens were fractured at the base metal(BM),implying a significant departure from conventional fracture modes of welded joints.The fusion zone(FZ)consists of ultrafine acicular α-Mg and equiaxed β-Li,with grain sizes reduced by approximately 90% and 80%,respectively,compared to the base metal.This results in a significant increase in microhardness of about 40%.A unique multiphase mixture was observed in the heat-affected zone(HAZ),which mainly consists of lamellar eutectoid structures,fine precipitates zone,and numerous fine Mg_(3)(Al,Zn)particles.This mixture was transformed from typical Li(Al,Zn)(a common softening phase)undergoing atomic diffusion and solid-state phase transformation during welding.It introduces a synergistic strengthening effect,making the heat-affected zone no longer the weakest part of the joint.This study provides valuable insights into the electron beam welding technology for Mg-Li alloys and offers theoretical support for manufacturing high-quality joints.展开更多
Lead-halide perovskite nanoparticles(LHP NPs) are highly promising materials for next-generation displays and solid-state lighting due to their exceptional optical properties. However, their inherent instability prese...Lead-halide perovskite nanoparticles(LHP NPs) are highly promising materials for next-generation displays and solid-state lighting due to their exceptional optical properties. However, their inherent instability presents a significant challenge. Recent advances have demonstrated that optoelectronic devices based on monolayer nanoparticle films exhibit both high luminescence efficiency and long-term stability.Our research demonstrates that mobility limitations and anisotropic alignments in CsPbBr3nanocube monolayer films are key to their stabilization, hindering spontaneous growth through face-to-face fusion and resulting in the formation of connecting necks in a diagonal direction. Introducing laser irradiation confirmed this by significantly accelerating nanocubes growth, increasing mobility, and enhancing local structural ordering, leading to larger and more regularly shaped nanosheets. Fourier transform infrared spectroscopy and energy dispersive spectroscopy line-scan analyses indicated that laser irradiation did not disrupt the ligand structure. Transmission electron microscopy and correlative cathodoluminescence electron microscopy revealed the effects of post-growth and heterogeneous structures, including enhanced luminescence and inhomogeneous intensity in the nanosheets. These findings deepen the understanding of the post-growth mechanism of monolayer nanoparticles and the structure-emission correlation and highlight the unique role of laser irradiation in directing the formation of well-defined and regular nanostructures.展开更多
Nucleotide binding domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3)is an NLR-protein family member that can be activated by diverse exogenous and endogenous stimuli but without direct binding of any of ...Nucleotide binding domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3)is an NLR-protein family member that can be activated by diverse exogenous and endogenous stimuli but without direct binding of any of these pathogen ligands.Biological studies show that inactive NLRP3 is usually in an as-sembly state and its activation requires a kinase protein,NEK7.However,our re-cent computational studies as well as other biological investigations have demonstrated that NEK7 does not play a significant role in the activation of NLRP3 assembly and activation.In-stead,biological studies suggest that NEK7 is essential in the dissociation of inactive NLRP3 assemblies.Despite extensive research,the dissociation mechanism of the inactive NLRP3 as-sembly remains largely elusive.In this work,an improved MM-PBSA method is applied to the protein-protein binding free energies in the inactive NLRP3 decamer.Combined with the po-tential mean force(PMF)computation for the 0°→5°conformational change,the standard free-energy change,ΔG^(0)is calculated for NEK7-driven association of the inactive NLRP3 de-camer.Our calculations show that in the absence of NEK7,the dissociation of the inactive NLRP3 decamer is an energetically unfavorable process(ΔG^(0)=99.69 kcal/mol),whereas upon NEK7 binding,the overall standard free energy differenceΔG^(0)=-24.21 kcal/mol is obtained for the inactive NLRP3 decamer dissociation.The free-energy difference calcula-tions in this work also disclose an energetically optimized dissociation pathway,along which the inactive NLRP3 decamer is disunited by a one-by-one dissociation mechanism.展开更多
The excavation of deep tunnels crossing faults is highly prone to triggering rockburst disasters,which has become a significant engineering issue.In this study,taking the fault-slip rockbursts from a deep tunnel in so...The excavation of deep tunnels crossing faults is highly prone to triggering rockburst disasters,which has become a significant engineering issue.In this study,taking the fault-slip rockbursts from a deep tunnel in southwestern China as the engineering prototype,large-scale three-dimensional(3D)physical model tests were conducted on a 3D-printed complex geological model containing two faults.Based on the selfdeveloped 3D loading system and excavation device,the macroscopic failure of fault-slip rockbursts was simulated indoors.The stress,strain,and fracturing characteristics of the surrounding rock near the two faults were systematically evaluated during excavation and multistage loading.The test results effectively revealed the evolution and triggering mechanism of fault-slip rockbursts.After the excavation of a highstress tunnel,stress readjustment occurred.Owing to the presence of these two faults,stress continued to accumulate in the rock mass between them,leading to the accumulation of fractures.When the shear stress on a fault surface exceeded its shear strength,sudden fault slip and dislocation occurred,thus triggering rockbursts.Rockbursts occurred twice in the vault between the two faults,showing obvious intermittent characteristics.The rockburst pit was controlled by two faults.When the faults remained stable,tensile failure predominated in the surrounding rock.However,when the fault slip was triggered,shear failure in the surrounding rock increased.These findings provide valuable insights for enhancing the comprehension of fault-slip rockbursts.展开更多
To explore the denitration mechanism of iron-vanadium/activated carbon(Fe-V/AC)catalysts in ammonia-selective catalytic reduction(NH_(3)-SCR),the physicochemical properties of Fe-V/AC catalysts were characterized.The ...To explore the denitration mechanism of iron-vanadium/activated carbon(Fe-V/AC)catalysts in ammonia-selective catalytic reduction(NH_(3)-SCR),the physicochemical properties of Fe-V/AC catalysts were characterized.The denitration activities of the Fe-V/AC catalysts in the range of 150-300℃ were evaluated.The increase in denitration temperature leads to the highest and fastest recovery rate of NO conversion in the 10Fe-15V/AC catalyst.However,more metal oxides were attached to the catalyst surface as the V loading increased,and the accumulation occurred.The surface-active components are FeO,Fe_(2)O_(3),Fe_(3)O_(4),VO_(2),and V_(2)O_(5).In addition,the increase in the V loading induced a series of modification effects.A large amount of Fe^(3+)was reduced to Fe^(2+),and a large amount of V^(4+)was oxidized to V^(5+).The surface oxygen species(O_(α))were transformed into lattice oxygen(O_(β)).The presence of a large amount of V species deteriorated the pore-structure parameters and destroyed the oxygen-containing functional groups.Increasing the V loading can effectively increase the Lewis acid sites,thereby promoting NH_(3) adsorption and NO reduction and increasing the stretching vibration of weakly adsorbed ammonia species on the catalyst.The NH_(3) adsorption process produces a notable increase in the concentration of monodentate nitrite(NH_(4)^(+)).The NH_(3)-SCR denitration mechanism of the Fe-V/AC catalyst includes reaction gas adsorption,catalytic denitration of metal active components,and gas desorption.展开更多
To clarify the mechanism of differential enrichment of intrasource shale oil,taking the third of seventh member of the Triassic Yanchang Formation(Chang 7_(3)submember for short)in the Ordos Basin,NW China as an examp...To clarify the mechanism of differential enrichment of intrasource shale oil,taking the third of seventh member of the Triassic Yanchang Formation(Chang 7_(3)submember for short)in the Ordos Basin,NW China as an example,we integrated high-resolution scanning electron microscopy(SEM),optical microscopy,laser Raman spectroscopy,rock pyrolysis,and organic solvent extraction experiments to identify solid bitumen of varying origins,obtain direct evidence of intrasource micro-migration of shale oil,and establish the coupling between the shale nano/micro-fabric and the oil generation,migration and accumulation.The Chang 7_(3)shale with rich alginite in laminae has the highest hydrocarbon generation potential but a low thermal transformation ratio.Frequent alternations of micron-scale argillaceous-felsic laminae enhance the hydrocarbon expulsion efficiency,yielding consistent aromaticity between in-situ and migrated solid bitumen.Mudstone laminae rich in terrestrial organic matter(OM)and clay minerals exhibit lower hydrocarbon generation threshold but stronger hydrocarbon retention capacity,with a certain amount of light oil/bitumen preserved to differentiate the chemical structure of in-situ versus migrated bitumen.Tuffaceous and sandy laminae contain abundant felsic minerals and migrated bitumen.Tuffaceous laminae develop high-angle microfractures under shale overpressure,facilitating oil charging into rigid mineral intergranular pores of sandy laminae.Fractionation during micro-migration progressively decreases the aromatization of solid bitumen from shale,through tuffaceous and mudstone,to sandy laminae,while increasing light hydrocarbon components and enhancing OM-hosted pore development.The intrasource micro-migration and enrichment of the Chang 7_(3)shale oil result from synergistic organic-inorganic diagenesis,with crude oil component fractionation being a key mechanism for forming sweet spots in laminated shale oil reservoirs.展开更多
In sulfide-based all-solid-state lithium batteries(ASLBs),the development of high-capacity anode materials with stable interfaces to sulfide solid-state electrolytes(SSEs)is critical.Here,In_(2)O_(3)is explored as an ...In sulfide-based all-solid-state lithium batteries(ASLBs),the development of high-capacity anode materials with stable interfaces to sulfide solid-state electrolytes(SSEs)is critical.Here,In_(2)O_(3)is explored as an anode material for ASLBs for the first time,demonstrating exceptional interfacial stability and electrochemical performance.The In_(2)O_(3)anode,with a substantial mass loading of 7.64 mg cm^(-2),sustains a charge-specific capacity of528.0 mAh g^(-1)(4.03 mAh cm^(-2))at a current density of0.76 mA cm^(-2)over 500 cycles,with a capacity retention of 81.2%.Additionally,it exhibits remarkable long-term cycling stability(2900 cycles)under a high current density of 3.82 mA cm^(-2),with an exceptionally low decay rate of0.016%per cycle.The charge-discharge mechanism of the In_(2)O_(3)anode is elucidated in detail,revealing that the electrochemical evolution of In_(2)O_(3)in ASLBs involves notonly the alloying/dealloying process of indium(In)but also a conversion reaction between In and Li_(2)O.Notably,as cycling progresses,the conversion reaction of In and Li_(2)O diminishes,with the reversible alloy ing/dealloy ing process becoming predominant.This work offers valuable insights for advancing oxide anode materials in sulfide-based ASLBs.展开更多
Accurate and efficient brain tumor segmentation is essential for early diagnosis,treatment planning,and clinical decision-making.However,the complex structure of brain anatomy and the heterogeneous nature of tumors pr...Accurate and efficient brain tumor segmentation is essential for early diagnosis,treatment planning,and clinical decision-making.However,the complex structure of brain anatomy and the heterogeneous nature of tumors present significant challenges for precise anomaly detection.While U-Net-based architectures have demonstrated strong performance in medical image segmentation,there remains room for improvement in feature extraction and localization accuracy.In this study,we propose a novel hybrid model designed to enhance 3D brain tumor segmentation.The architecture incorporates a 3D ResNet encoder known for mitigating the vanishing gradient problem and a 3D U-Net decoder.Additionally,to enhance the model’s generalization ability,Squeeze and Excitation attention mechanism is integrated.We introduce Gabor filter banks into the encoder to further strengthen the model’s ability to extract robust and transformation-invariant features from the complex and irregular shapes typical in medical imaging.This approach,which is not well explored in current U-Net-based segmentation frameworks,provides a unique advantage by enhancing texture-aware feature representation.Specifically,Gabor filters help extract distinctive low-level texture features,reducing the effects of texture interference and facilitating faster convergence during the early stages of training.Our model achieved Dice scores of 0.881,0.846,and 0.819 for Whole Tumor(WT),Tumor Core(TC),and Enhancing Tumor(ET),respectively,on the BraTS 2020 dataset.Cross-validation on the BraTS 2021 dataset further confirmed the model’s robustness,yielding Dice score values of 0.887 for WT,0.856 for TC,and 0.824 for ET.The proposed model outperforms several state-of-the-art existing models,particularly in accurately identifying small and complex tumor regions.Extensive evaluations suggest integrating advanced preprocessing with an attention-augmented hybrid architecture offers significant potential for reliable and clinically valuable brain tumor segmentation.展开更多
The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonizatio...The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.展开更多
基金Project supported by the Natural Science Foundation Innovation Group Project of Hubei Province(2023AFA044)the National Natural Science Foundation of China(52222405)+1 种基金the Science and Technology Research Project of Education Department of Hubei Province(Q20221505)the China Postdoctoral Science(2023M731041)。
文摘In order to reveal the effect of 2-hydroxy-3-naphthyl hydroxamic acid(H205)on the flotation behavior and action mechanism of bastnaesite,single-mineral flotation experiments of bastnaesite were conducted.The flotation recovery of bastnaesites can be achieved more than 90%when the aeration rate is 40 mL/min,the rotational speed is 200 r/min,the H205 dosage is 120 mg/L,and the pulp pH ranges from 7 to 9.The action mechanism of H205 on the surface of bastnaesite was studied by simultaneous thermogravimetry and differential scanning calorimetry(TG-DSC),Zeta potential measurements,Fourier transform-infrared spectra(FT-IR)and X-ray photoelectron spectroscopy(XPS).These analysis results show that under suitable flotation conditions,H205 has an obvious adsorption phenomenon on the surface of bastnaesite.The adsorption involves electrostatic interactions and chemical interactions,namely H205 has a strong collecting ability of bastnaesite due to the synergism of electrostatic adsorption and chemical adsorption.This study systematically reveals the flotation behavior and adsorption mechanism of H205 on the surface of bastnaesite,and provides useful theoretical guidance for efficient flotation separation of bastnaesite.
基金supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.12425209)the National Natural Science Foundation of China(Grant No.U20A20390,11827803,12172034,11822201,62004056,62104058,62271269).
文摘Neuromorphic devices have shown great potential in simulating the function of biological neurons due to their efficient parallel information processing and low energy consumption.MXene-Ti_(3)C_(2)T_(x),an emerging twodimensional material,stands out as an ideal candidate for fabricating neuromorphic devices.Its exceptional electrical performance and robust mechanical properties make it an ideal choice for this purpose.This review aims to uncover the advantages and properties of MXene-Ti_(3)C_(2)T_(x)in neuromorphic devices and to promote its further development.Firstly,we categorize several core physical mechanisms present in MXene-Ti_(3)C_(2)T_(x)neuromorphic devices and summarize in detail the reasons for their formation.Then,this work systematically summarizes and classifies advanced techniques for the three main optimization pathways of MXene-Ti_(3)C_(2)T_(x),such as doping engineering,interface engineering,and structural engineering.Significantly,this work highlights innovative applications of MXene-Ti_(3)C_(2)T_(x)neuromorphic devices in cutting-edge computing paradigms,particularly near-sensor computing and in-sensor computing.Finally,this review carefully compiles a table that integrates almost all research results involving MXene-Ti_(3)C_(2)T_(x)neuromorphic devices and discusses the challenges,development prospects,and feasibility of MXene-Ti_(3)C_(2)T_(x)-based neuromorphic devices in practical applications,aiming to lay a solid theoretical foundation and provide technical support for further exploration and application of MXene-Ti_(3)C_(2)T_(x)in the field of neuromorphic devices.
基金financially supported by the National Defense Basic Research Program(No.JCKY2023204A005)Project of High Modulus Magnesium Alloy Forgings(JXXT-2023-014hbza)+1 种基金Research Program of Joint Research Center of Advanced Spaceflight Technologies(No.USCAST2023-3)Major Scientific and Technological Innovation Project of Luoyang(No.2201029A).
文摘Nearly undamaged joints of electron beam welded(EBW)dual-phase Mg-8Li-3Al-2Zn-0.5Y alloy were achieved with joint coefficients exceeding 95%.All specimens were fractured at the base metal(BM),implying a significant departure from conventional fracture modes of welded joints.The fusion zone(FZ)consists of ultrafine acicular α-Mg and equiaxed β-Li,with grain sizes reduced by approximately 90% and 80%,respectively,compared to the base metal.This results in a significant increase in microhardness of about 40%.A unique multiphase mixture was observed in the heat-affected zone(HAZ),which mainly consists of lamellar eutectoid structures,fine precipitates zone,and numerous fine Mg_(3)(Al,Zn)particles.This mixture was transformed from typical Li(Al,Zn)(a common softening phase)undergoing atomic diffusion and solid-state phase transformation during welding.It introduces a synergistic strengthening effect,making the heat-affected zone no longer the weakest part of the joint.This study provides valuable insights into the electron beam welding technology for Mg-Li alloys and offers theoretical support for manufacturing high-quality joints.
基金National Key Research and Development Program of China(2023YFA1507602)National Natural Science Foundation of China (22171010, 62174011)。
文摘Lead-halide perovskite nanoparticles(LHP NPs) are highly promising materials for next-generation displays and solid-state lighting due to their exceptional optical properties. However, their inherent instability presents a significant challenge. Recent advances have demonstrated that optoelectronic devices based on monolayer nanoparticle films exhibit both high luminescence efficiency and long-term stability.Our research demonstrates that mobility limitations and anisotropic alignments in CsPbBr3nanocube monolayer films are key to their stabilization, hindering spontaneous growth through face-to-face fusion and resulting in the formation of connecting necks in a diagonal direction. Introducing laser irradiation confirmed this by significantly accelerating nanocubes growth, increasing mobility, and enhancing local structural ordering, leading to larger and more regularly shaped nanosheets. Fourier transform infrared spectroscopy and energy dispersive spectroscopy line-scan analyses indicated that laser irradiation did not disrupt the ligand structure. Transmission electron microscopy and correlative cathodoluminescence electron microscopy revealed the effects of post-growth and heterogeneous structures, including enhanced luminescence and inhomogeneous intensity in the nanosheets. These findings deepen the understanding of the post-growth mechanism of monolayer nanoparticles and the structure-emission correlation and highlight the unique role of laser irradiation in directing the formation of well-defined and regular nanostructures.
基金supported by Ministry of Science and Technology of China(2022YFA1303100)the National Natural Science Foundation of China(No.32090040)。
文摘Nucleotide binding domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3)is an NLR-protein family member that can be activated by diverse exogenous and endogenous stimuli but without direct binding of any of these pathogen ligands.Biological studies show that inactive NLRP3 is usually in an as-sembly state and its activation requires a kinase protein,NEK7.However,our re-cent computational studies as well as other biological investigations have demonstrated that NEK7 does not play a significant role in the activation of NLRP3 assembly and activation.In-stead,biological studies suggest that NEK7 is essential in the dissociation of inactive NLRP3 assemblies.Despite extensive research,the dissociation mechanism of the inactive NLRP3 as-sembly remains largely elusive.In this work,an improved MM-PBSA method is applied to the protein-protein binding free energies in the inactive NLRP3 decamer.Combined with the po-tential mean force(PMF)computation for the 0°→5°conformational change,the standard free-energy change,ΔG^(0)is calculated for NEK7-driven association of the inactive NLRP3 de-camer.Our calculations show that in the absence of NEK7,the dissociation of the inactive NLRP3 decamer is an energetically unfavorable process(ΔG^(0)=99.69 kcal/mol),whereas upon NEK7 binding,the overall standard free energy differenceΔG^(0)=-24.21 kcal/mol is obtained for the inactive NLRP3 decamer dissociation.The free-energy difference calcula-tions in this work also disclose an energetically optimized dissociation pathway,along which the inactive NLRP3 decamer is disunited by a one-by-one dissociation mechanism.
基金funding support from the National Natural Science Foundation of China(Grant Nos.42177136 and 52309126).
文摘The excavation of deep tunnels crossing faults is highly prone to triggering rockburst disasters,which has become a significant engineering issue.In this study,taking the fault-slip rockbursts from a deep tunnel in southwestern China as the engineering prototype,large-scale three-dimensional(3D)physical model tests were conducted on a 3D-printed complex geological model containing two faults.Based on the selfdeveloped 3D loading system and excavation device,the macroscopic failure of fault-slip rockbursts was simulated indoors.The stress,strain,and fracturing characteristics of the surrounding rock near the two faults were systematically evaluated during excavation and multistage loading.The test results effectively revealed the evolution and triggering mechanism of fault-slip rockbursts.After the excavation of a highstress tunnel,stress readjustment occurred.Owing to the presence of these two faults,stress continued to accumulate in the rock mass between them,leading to the accumulation of fractures.When the shear stress on a fault surface exceeded its shear strength,sudden fault slip and dislocation occurred,thus triggering rockbursts.Rockbursts occurred twice in the vault between the two faults,showing obvious intermittent characteristics.The rockburst pit was controlled by two faults.When the faults remained stable,tensile failure predominated in the surrounding rock.However,when the fault slip was triggered,shear failure in the surrounding rock increased.These findings provide valuable insights for enhancing the comprehension of fault-slip rockbursts.
基金financially supported by National Natural Science Foundation of China(No.52264043).
文摘To explore the denitration mechanism of iron-vanadium/activated carbon(Fe-V/AC)catalysts in ammonia-selective catalytic reduction(NH_(3)-SCR),the physicochemical properties of Fe-V/AC catalysts were characterized.The denitration activities of the Fe-V/AC catalysts in the range of 150-300℃ were evaluated.The increase in denitration temperature leads to the highest and fastest recovery rate of NO conversion in the 10Fe-15V/AC catalyst.However,more metal oxides were attached to the catalyst surface as the V loading increased,and the accumulation occurred.The surface-active components are FeO,Fe_(2)O_(3),Fe_(3)O_(4),VO_(2),and V_(2)O_(5).In addition,the increase in the V loading induced a series of modification effects.A large amount of Fe^(3+)was reduced to Fe^(2+),and a large amount of V^(4+)was oxidized to V^(5+).The surface oxygen species(O_(α))were transformed into lattice oxygen(O_(β)).The presence of a large amount of V species deteriorated the pore-structure parameters and destroyed the oxygen-containing functional groups.Increasing the V loading can effectively increase the Lewis acid sites,thereby promoting NH_(3) adsorption and NO reduction and increasing the stretching vibration of weakly adsorbed ammonia species on the catalyst.The NH_(3) adsorption process produces a notable increase in the concentration of monodentate nitrite(NH_(4)^(+)).The NH_(3)-SCR denitration mechanism of the Fe-V/AC catalyst includes reaction gas adsorption,catalytic denitration of metal active components,and gas desorption.
基金Supported by the National Science and Technology Major Project(2024ZD1404901,2017ZX05035)Strategic Priority Research Program(Category B)of the Chinese Academy of Sciences(XDB10050100).
文摘To clarify the mechanism of differential enrichment of intrasource shale oil,taking the third of seventh member of the Triassic Yanchang Formation(Chang 7_(3)submember for short)in the Ordos Basin,NW China as an example,we integrated high-resolution scanning electron microscopy(SEM),optical microscopy,laser Raman spectroscopy,rock pyrolysis,and organic solvent extraction experiments to identify solid bitumen of varying origins,obtain direct evidence of intrasource micro-migration of shale oil,and establish the coupling between the shale nano/micro-fabric and the oil generation,migration and accumulation.The Chang 7_(3)shale with rich alginite in laminae has the highest hydrocarbon generation potential but a low thermal transformation ratio.Frequent alternations of micron-scale argillaceous-felsic laminae enhance the hydrocarbon expulsion efficiency,yielding consistent aromaticity between in-situ and migrated solid bitumen.Mudstone laminae rich in terrestrial organic matter(OM)and clay minerals exhibit lower hydrocarbon generation threshold but stronger hydrocarbon retention capacity,with a certain amount of light oil/bitumen preserved to differentiate the chemical structure of in-situ versus migrated bitumen.Tuffaceous and sandy laminae contain abundant felsic minerals and migrated bitumen.Tuffaceous laminae develop high-angle microfractures under shale overpressure,facilitating oil charging into rigid mineral intergranular pores of sandy laminae.Fractionation during micro-migration progressively decreases the aromatization of solid bitumen from shale,through tuffaceous and mudstone,to sandy laminae,while increasing light hydrocarbon components and enhancing OM-hosted pore development.The intrasource micro-migration and enrichment of the Chang 7_(3)shale oil result from synergistic organic-inorganic diagenesis,with crude oil component fractionation being a key mechanism for forming sweet spots in laminated shale oil reservoirs.
基金financially supported by the National Natural Science Foundation of China(No.22301151)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2022QN05024)+1 种基金the Science and Technology Projects of Inner Mongolia Autonomous Region(No.2024SKYPT0011)the Science and Technology Planning Project of Hohhot,China(No.2024-JieBangGuaShuai-Gao-4)
文摘In sulfide-based all-solid-state lithium batteries(ASLBs),the development of high-capacity anode materials with stable interfaces to sulfide solid-state electrolytes(SSEs)is critical.Here,In_(2)O_(3)is explored as an anode material for ASLBs for the first time,demonstrating exceptional interfacial stability and electrochemical performance.The In_(2)O_(3)anode,with a substantial mass loading of 7.64 mg cm^(-2),sustains a charge-specific capacity of528.0 mAh g^(-1)(4.03 mAh cm^(-2))at a current density of0.76 mA cm^(-2)over 500 cycles,with a capacity retention of 81.2%.Additionally,it exhibits remarkable long-term cycling stability(2900 cycles)under a high current density of 3.82 mA cm^(-2),with an exceptionally low decay rate of0.016%per cycle.The charge-discharge mechanism of the In_(2)O_(3)anode is elucidated in detail,revealing that the electrochemical evolution of In_(2)O_(3)in ASLBs involves notonly the alloying/dealloying process of indium(In)but also a conversion reaction between In and Li_(2)O.Notably,as cycling progresses,the conversion reaction of In and Li_(2)O diminishes,with the reversible alloy ing/dealloy ing process becoming predominant.This work offers valuable insights for advancing oxide anode materials in sulfide-based ASLBs.
基金the National Science and Technology Council(NSTC)of the Republic of China,Taiwan,for financially supporting this research under Contract No.NSTC 112-2637-M-131-001.
文摘Accurate and efficient brain tumor segmentation is essential for early diagnosis,treatment planning,and clinical decision-making.However,the complex structure of brain anatomy and the heterogeneous nature of tumors present significant challenges for precise anomaly detection.While U-Net-based architectures have demonstrated strong performance in medical image segmentation,there remains room for improvement in feature extraction and localization accuracy.In this study,we propose a novel hybrid model designed to enhance 3D brain tumor segmentation.The architecture incorporates a 3D ResNet encoder known for mitigating the vanishing gradient problem and a 3D U-Net decoder.Additionally,to enhance the model’s generalization ability,Squeeze and Excitation attention mechanism is integrated.We introduce Gabor filter banks into the encoder to further strengthen the model’s ability to extract robust and transformation-invariant features from the complex and irregular shapes typical in medical imaging.This approach,which is not well explored in current U-Net-based segmentation frameworks,provides a unique advantage by enhancing texture-aware feature representation.Specifically,Gabor filters help extract distinctive low-level texture features,reducing the effects of texture interference and facilitating faster convergence during the early stages of training.Our model achieved Dice scores of 0.881,0.846,and 0.819 for Whole Tumor(WT),Tumor Core(TC),and Enhancing Tumor(ET),respectively,on the BraTS 2020 dataset.Cross-validation on the BraTS 2021 dataset further confirmed the model’s robustness,yielding Dice score values of 0.887 for WT,0.856 for TC,and 0.824 for ET.The proposed model outperforms several state-of-the-art existing models,particularly in accurately identifying small and complex tumor regions.Extensive evaluations suggest integrating advanced preprocessing with an attention-augmented hybrid architecture offers significant potential for reliable and clinically valuable brain tumor segmentation.
基金supported by the National Natural Science Foundation of China(Nos.22276060 and 21976059)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012636)China Scholarship Council Scholarship(No.201906155006)。
文摘The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.
