Integrating a heterogeneous structure can significantly enhance the strength-ductility synergy of composites.However,the relationship between hetero-deformation induced(HDI)strain hardening and dislocation activity ca...Integrating a heterogeneous structure can significantly enhance the strength-ductility synergy of composites.However,the relationship between hetero-deformation induced(HDI)strain hardening and dislocation activity caused by heterogeneous structures in the magnesium matrix composite remains unclear.In this study,a dual-heterogeneous TiC/AZ61 composite exhibits significantly improved plastic elongation(PEL)by nearly one time compared to uniform FG composite,meanwhile maintaining a high strength(UTS:417 MPa).This is because more severe deformation inhomogeneity in heterogeneous structure leads to more geometrically necessary dislocations(GNDs)accumulation and stronger HDI stress,resulting in higher HDI hardening compared to FG and CG composites.During the early stage of plastic deformation,the pile-up types of GND in the FG zone and CG zone are significantly different.GNDs tend to form substructures in the FG zone instead of the CG zone.They only accumulate at grain boundaries of the CG region,thereby leading to obviously increased back stress in the CG region.In the late deformation stage,the elevated HDI stress activates the new〈c+a〉dislocations in the CG region,resulting in dislocation entanglements and even the formation of substructures,further driving the high hardening in the heterogeneous composite.However,For CG composite,〈c+a〉dislocations are not activated even under large plastic strains,and only〈a〉dislocations pile up at grain boundaries and twin boundaries.Our work provides an in-depth understanding of dislocation variation and HDI hardening in heterogeneous magnesium-based composites.展开更多
This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composi...This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116 % and a remarkable 165 % improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45 % of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219 %) is observed to be more than double that in FG zones (95 %), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.展开更多
Wire arc additive manufacturing(WAAM)technology has been used to fabricate the multi-layer single-pass deposited wall of AZ80M magnesium(Mg)alloy by gas tungsten arc welding.The formability,thermal cycles,microstructu...Wire arc additive manufacturing(WAAM)technology has been used to fabricate the multi-layer single-pass deposited wall of AZ80M magnesium(Mg)alloy by gas tungsten arc welding.The formability,thermal cycles,microstructural evolution and mechanical properties of the WAAM AZ80M Mg alloy were investigated.The results show that there was significant difference in the temperature variation and the geometries between the original several layers and the subsequent deposited layers.Owing to the arc energy input,the interpass temperature rised rapidly and then stabilized at 150℃.As a result,the width of the deposited wall increased and then kept stable.There were obvious differences in the microstructure of the WAAM AZ80M Mg alloy among the top zone,intermediate zone and bottom zone of deposited wall.During the arc deposition process,theβphase of the WAAM AZ80M Mg alloy redissolved due to the cyclic heat accumulation,and then precipitated in the grain boundary.The cyclic heat accumulation also led to weakening of dendrite segregation.From the substrate to the top zone,the hardness of the deposited wall decreased gradually,and the intermediate zone which was the main body of deposited wall had relatively uniform hardness.The tensile properties of the WAAM AZ80M Mg alloy were different between the vertical direction and the horizontal direction.And the maximum ultimate tensile strength of the WAAM AZ80M Mg alloy was 308 MPa which was close to that of the as-extruded AZ80M Mg alloy.展开更多
To maximize the benefits of wire arc additive manufacturing(WAAM)processes,the effect of post-deposition heat treatment on the microstructure and mechanical properties of WAAM AZ80M magnesium(Mg)alloy was investigated...To maximize the benefits of wire arc additive manufacturing(WAAM)processes,the effect of post-deposition heat treatment on the microstructure and mechanical properties of WAAM AZ80M magnesium(Mg)alloy was investigated.Three different heat treatment procedures(T4,T5 and T6)were performed.According to the results,after T4 heat treatment,the microsegregation of alloying elements was improved with the eutectic structure dissolved.Samples after T5 heat treatment inherited the net-like distribution of secondary phases similar to the as-deposited sample,where the eutectic structure covering the interdendritic regions and theβ-phase precipitated around the eutectic structure.After T6 heat treatment,the tinyβ-phases re-precipitated from the matrix and distributed in inner and outer of the grains.The hardness distribution of the samples went through T4 and T6 heat treatment was more uniform in comparison to that of T5 heat treated samples.The tensile test showed that the T6 heat treatment improved the strength and ductility,and the anisotropy between horizontal and vertical can be eliminated.Moreover,T4 treated samples exhibited highest ductility.展开更多
In this study,the nano-TiC/AZ61 composites with different heterogeneous bimodal grain(HBG)structures and uniform structure are obtained by regulating the extrusion speed.The effect of HBG structure on the mechanical p...In this study,the nano-TiC/AZ61 composites with different heterogeneous bimodal grain(HBG)structures and uniform structure are obtained by regulating the extrusion speed.The effect of HBG structure on the mechanical properties of the composites is investigated.The increasing ductility and toughening mechanism of HBG magnesium matrix composites are carefully discussed.When the extrusion speed increases from 0.75 mm/s to 2.5 mm/s or 3.5 mm/s,the microstructure transforms from uniform to HBG structure.Compared with Uniform-0.75 mm/s composite,Heterogeneous-3.5 mm/s composite achieves a 116.7%increase in ductility in the plastic deformation stage and almost no reduction in ultimate tensile strength.This is mainly because the lower plastic deformation inhomogeneity and higher strain hardening due to hetero-deformation induced(HDI)hardening.Moreover,Heterogeneous-3.5 mm/s composite achieves a 108.3%increase in toughness compared with the Uniform-0.75 mm/s composite.It is mainly because coarse grain(CG)bands can capture and blunt cracks,thereby increasing the energy dissipation for crack propagation and improving toughness.In addition,the CG band of the Heterogeneous-3.5 mm/s composite with larger grain size and lower dislocation density is more conducive to obtaining higher strain hardening and superior blunting crack capability.Thus,the increased ductility and toughness of the Heterogeneous-3.5 mm/s composite is more significant than that Heterogeneous-2.5 mm/s composite.展开更多
With the continual deployment of power-electronics-interfaced renewable energy resources,increasing privacy concerns due to deregulation of electricity markets,and the diversification of demand-side activities,traditi...With the continual deployment of power-electronics-interfaced renewable energy resources,increasing privacy concerns due to deregulation of electricity markets,and the diversification of demand-side activities,traditional knowledge-based power system dynamic modeling methods are faced with unprecedented challenges.Data-driven modeling has been increasingly studied in recent years because of its lesser need for prior knowledge,higher capability of handling large-scale systems,and better adaptability to variations of system operating conditions.This paper discusses about the motivations and the generalized process of datadriven modeling,and provides a comprehensive overview of various state-of-the-art techniques and applications.It also comparatively presents the advantages and disadvantages of these methods and provides insight into outstanding challenges and possible research directions for the future.展开更多
The Mesoproterozoic rifts are developed in the Ordos Basin located in the western margin of the North China Plate.Based on the latest 3D seismic data and previous research results,this study intends to discuss the zon...The Mesoproterozoic rifts are developed in the Ordos Basin located in the western margin of the North China Plate.Based on the latest 3D seismic data and previous research results,this study intends to discuss the zonal differential deformation characteristics and genetic mechanism of the Mesoproterozoic rifts in the Ordos Basin.NE-trending rifts are developed in the Mesoproterozoic in the south-central Ordos Basin,the main part of which are located near the western margin of the North China Plate.NNW-trending rifts are developed in the north of the basin,while NW-NNW rifts in the Mesoproterozoic in Hangjinqi area.The genetic mechanism of the Mesoproterozoic rifts is related to regional extensional stress field,plate boundary conditions and internal preexisting structures.The main extensional stress direction strikes NWW-SSE(120°)in the western margin of the North China Plate,based on the forward rift trend of the northern Mesoproterozoic.In Hangjinqi area,the reactivation of the existing NWtrending Wulansu fault and NW-NW-trending Daolao fault,results in dextral shear stress field.The boundary between the western margin of the North China Plate and its adjacent plates forms a nearly NS-trending preexisting basement tectonic belt,which intersects with the NWW-SSE(120°)extensional stress at an acute angle of 60°.Therefore,the western margin of the North China Plate is formed by oblique normal faults under oblique extension.Due to the long time span of Columbia Supercontinent breakup(1.8e1.6 Ga),the oblique rift in the south-central Ordos Basin is formed under the continuous oblique extension at the western margin of the North China Plate.展开更多
Schedule management is the crucial capability for large-scale coal mining investors to successful finish the construction project, which could get by the accumulation of the long-time institutional executive force and...Schedule management is the crucial capability for large-scale coal mining investors to successful finish the construction project, which could get by the accumulation of the long-time institutional executive force and ability training. By using factor analysis and validation analysis, extracted control factors of schedule management from data have been made in large coal mine construction companies. Some control factors have a greater influence on the schedule management which are the system factor, measures factor, economic controlling factor, behavioral factor, process factor, organization factor, thus the enterprise schedule management system should include the terms of the above factors.展开更多
Triple-negative breast cancer(TNBC),the most aggressive subtype of breast cancer,notably lacks effective treatment strategies.Although androgen receptor(AR)has emerged as a potential therapeutic target for TNBC,monoth...Triple-negative breast cancer(TNBC),the most aggressive subtype of breast cancer,notably lacks effective treatment strategies.Although androgen receptor(AR)has emerged as a potential therapeutic target for TNBC,monotherapy with AR inhibitors has proven to be of restricted efficacy.Aiming to develop superior therapeutic approaches,a comprehensive drug library screening was conducted.The ERK inhibitor GDC-0994 exhibited significant synergistic effects with the AR inhibitor bicalutamide.Transcriptome sequencing showed that this combination therapy activates ferroptosis,as evidenced by elevated ROS,increased Fe^(2+) levels,a reduced GSH/GSSG ratio,and lipid peroxide accumulation(MDA and 4-HNE).FOXC2 was identified as a key mediator of this synergy.Specifically,the combination therapy inhibits FOXC2-driven EMT and induces ferroptosis via the FOXC2-Hippo signaling axis,suppressing tumor proliferation,migration,and invasion.In summary,this study uncovers the value of AR/ERK co-targeting in TNBC,which might potentiate the development of novel targeted therapeutic strategies in TNBC.展开更多
Plastic strain in polycrystalline metals is highly localized in grain boundaries(GBs),slip bands(SBs)and twins.While extensive research has focused on intra-granular deformation mechanisms such as slip and twinning,st...Plastic strain in polycrystalline metals is highly localized in grain boundaries(GBs),slip bands(SBs)and twins.While extensive research has focused on intra-granular deformation mechanisms such as slip and twinning,strain localization at GBs has been largely overlooked.In this study,high-resolution digital image correlation(HRDIC)was employed to capture the strain distribution and its evolution during tension in an extruded pure Mg sheet.Particular attention was paid to strain localization at GBs and its governing factors.Results reveal that,at 3%applied strain,approximately 10%of GBs were categorized as extremely-high-strain GBs(defined as the GB where at least 20 data points have an effective shear strain(ε_(eff))value exceeding the 99th percentile of the overallεeff distribution),and the majority(84%)of them were observed to deform at even 0.5%applied strain.This suggests that early-stage deformation plays a critical role in subsequent GB strain localization.The mean strain value and grain boundary sliding(GBS)displacement of GBs increased significantly with applied strain,with progressively accelerating increasing rates observed in most instances.Most(~62%)GBs exhibiting slip transfer showed low strain,while a small fraction(~8%)of them exhibited extremely high strain.This indicates that slip transfer can mitigate GB strain localization in most cases.However,complex local conditions are also critical,and case-by-case analysis is essential.Moreover,GBs with misorientation angles ranging from 50°to 80°were found to be more likely to exhibit extremely high strain.This work provides valuable insights into GB strain localization,which is critical for further understanding the plastic deformation of polycrystalline Mg.展开更多
Background:Triple-negative breast cancer(TNBC)is an aggressive type of breast cancer associated with poor prognosis and limited treatment options.The androgen receptor(AR)has emerged as a potential therapeutic target ...Background:Triple-negative breast cancer(TNBC)is an aggressive type of breast cancer associated with poor prognosis and limited treatment options.The androgen receptor(AR)has emerged as a potential therapeutic target for luminal androgen receptor(LAR)TNBC.However,multiple studies have claimed that anti-androgen therapy for AR-positive TNBC only has limited clinical benefits.This study aimed to investigate the role of AR in TNBC and its detailed mechanism.Methods:Immunohistochemistry and TNBC tissue sections were applied to investigate AR and nectin cell adhesion molecule 4(NECTIN4)expression in TNBC tissues.Then,in vitro and in vivo assays were used to explore the function of AR and estrogen receptor beta(ERβ)in TNBC.Chromatin immunoprecipitation sequencing(ChIP-seq),co-immunoprecipitation(co-IP),molecular docking method,and luciferase reporter assay were performed to identify key molecules that affect the function of AR.Results:Based on the TNBC tissue array analysis,we revealed that ERβand AR were positive in 21.92%(32/146)and 24.66%(36/146)of 146 TNBC samples,respectively,and about 13.70%(20/146)of TNBC patients were ERβpositive and AR positive.We further demonstrated the pro-tumoral effects of AR on TNBC cells,however,the oncogenic biology was significantly suppressed when ERβtransfection in LAR TNBC cell lines but not in AR-negative TNBC.Mechanistically,we identified that NECTIN4 promoter–42 bp to–28 bp was an AR response element,and that ERβinteracted with AR thus impeding the AR-mediated NECTIN4 transcription which promoted epithelial–mesenchymal transition in tumor progression.Conclusions:This study suggests that ERβfunctions as a suppressor mediating the effect of AR in TNBC prognosis and cell proliferation.Therefore,our current research facilitates a better understanding of the role and mechanisms of AR in TNBC carcinogenesis.展开更多
Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize wi...Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize with enzalutamide,a second-generation AR inhibitor,in TNBC.By using a strategy for screening drug combinations based on the Sensitivity Index(SI),we found that MK-8776,a selective checkpoint kinase1(CHK1)inhibitor,showed favorable synergism with enzalutamide in AR-positive TNBC.The combination of enzalutamide and MK-8776 was found to exert more significant anti-tumor effects in TNBC than the single application of enzalutamide or MK-8776,respectively.Furthermore,a nanoparticle-based on hyaluronic acid(HA)-modified hollow-manganese dioxide(HMnO_(2)),named HMnE&M@H,was established to encapsulate and deliver enzalutamide and MK-8776.This HA-modified nanosystem managed targeted activation via pH/glutathione responsiveness.HMnE&M@H repressed tumor growth more obviously than the simple addition of enzalutamide and MK-8776 without a carrier.Collectively,our study elucidated the synergy of enzalutamide and MK-8776 in TNBC and developed a novel tumor-targeted nano drug delivery system HMnE&M@H,providing a potential therapeutic approach for the treatment of TNBC.展开更多
Activity hijacking is one of the most powerful attacks in Android. Though promising, all the prior activity hijacking attacks suffer from some limitations and have limited attack capabilities. They no longer pose secu...Activity hijacking is one of the most powerful attacks in Android. Though promising, all the prior activity hijacking attacks suffer from some limitations and have limited attack capabilities. They no longer pose security threats in recent Android due to the presence of effective defense mechanisms. In this work, we propose the first automated and adaptive activity hijacking attack, named VenomAttack, enabling a spectrum of customized attacks (e.g., phishing, spoofing, and DoS) on a large scale in recent Android, even the state-of-the-art defense mechanisms are deployed. Specifically, we propose to use hotpatch techniques to identify vulnerable devices and update attack payload without re-installation and re-distribution, hence bypassing offline detection. We present a newly-discovered flaw in Android and a bug in derivatives of Android, each of which allows us to check if a target app is running in the background or not, by which we can determine the right attack timing via a designed transparent activity. We also propose an automated fake activity generation approach, allowing large-scale attacks. Requiring only the common permission INTERNET, we can hijack activities at the right timing without destroying the GUI integrity of the foreground app. We conduct proof-of-concept attacks, showing that VenomAttack poses severe security risks on recent Android versions. The user study demonstrates the effectiveness of VenomAttack in real-world scenarios, achieving a high success rate (95%) without users’ awareness. That would call more attention to the stakeholders like Google.展开更多
Objective:To ensure the quality of Perilla frutescens(L.)Britt.and improve the associated benefits for stakeholders,this study analyzed the influences of different circulation channels and stakeholders on the quality,...Objective:To ensure the quality of Perilla frutescens(L.)Britt.and improve the associated benefits for stakeholders,this study analyzed the influences of different circulation channels and stakeholders on the quality,price,and other factors of P.frutescens with consideration to P.frutescens distribution.Method:We interviewed the local stakeholders and e-commerce platforms in Oroqen Autonomous Banner and Morin Dawa Daur Autonomous Banner regarding the origin,circulation,distribution,and prices of different medicinal parts of P.frutescens.In addition,the maximumentropymodel was used to predict the potential distribution of P.frutescens in the study area.According to the Chinese Pharmacopeia(2020 edition),we measured the content of index components in the collected Perillae Folium,Perillae Caulis,and Perillae Fructus samples and evaluated the quality of the samples by quantitative and cluster analyses.Remote sensing was employed to distinguish and calculate the P.frutescens area in highly suitable regions.The autoregressive integrated moving average model was adopted to analyze the Perillae Fructus price in the study area.Result:The results showed 8 value chains for P.frutescens.The cooperation chain between farmers and enterprises in the study area could maximize the benefits for all stakeholders and guarantee the quality of the medicinal materials.The results of the regionalization analysis showed that themost suitable area for planting P.frutescens was the junction between Oroqen Autonomous Banner and Morin Dawa Daur Autonomous Banner.Chemical results showed that Perillae Fructus and Perillae Caulis samples were unqualified andmostly purchased from e-commerce platforms.We identified 5 land types,among which the cultivated land area was 3247.7501 km2.The price of Perillae Fructus in the study area showed a rising trend,although this trend slowed down.Conclusion:This study involved various links in the production and circulation of medicinal materials from planting to consumption by consumers,which can help to facilitate the future research on any link.The findings help to guarantee the quality of medicinal materials and benefits of all stakeholders and promote the development of the P.frutescens industry in the study area.展开更多
基金support from the National Natural Science Foundation of China(No:52061040)China Postdoctoral Science Foundation(No:2021M692512)+1 种基金Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan Province(No:2023CL01)Open Projects of Key Laboratory of Advanced Technologies of Materials,Ministry of Education China,Southwest Jiaotong University(No:KLATM202003).
文摘Integrating a heterogeneous structure can significantly enhance the strength-ductility synergy of composites.However,the relationship between hetero-deformation induced(HDI)strain hardening and dislocation activity caused by heterogeneous structures in the magnesium matrix composite remains unclear.In this study,a dual-heterogeneous TiC/AZ61 composite exhibits significantly improved plastic elongation(PEL)by nearly one time compared to uniform FG composite,meanwhile maintaining a high strength(UTS:417 MPa).This is because more severe deformation inhomogeneity in heterogeneous structure leads to more geometrically necessary dislocations(GNDs)accumulation and stronger HDI stress,resulting in higher HDI hardening compared to FG and CG composites.During the early stage of plastic deformation,the pile-up types of GND in the FG zone and CG zone are significantly different.GNDs tend to form substructures in the FG zone instead of the CG zone.They only accumulate at grain boundaries of the CG region,thereby leading to obviously increased back stress in the CG region.In the late deformation stage,the elevated HDI stress activates the new〈c+a〉dislocations in the CG region,resulting in dislocation entanglements and even the formation of substructures,further driving the high hardening in the heterogeneous composite.However,For CG composite,〈c+a〉dislocations are not activated even under large plastic strains,and only〈a〉dislocations pile up at grain boundaries and twin boundaries.Our work provides an in-depth understanding of dislocation variation and HDI hardening in heterogeneous magnesium-based composites.
基金support from the China Scholarship Council(No.202107000038)support from the National Natural Science Foundation of China(Nos.52004227,52061040,and 12222209)the China Postdoctoral Science Foundation(No:2021M692512).
文摘This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116 % and a remarkable 165 % improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45 % of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219 %) is observed to be more than double that in FG zones (95 %), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.
基金This work was supported by the China Scholarship Coun-cil(No.201907000039)the national key research and devel-opment plan of China(grant number 2017YFB0305905)the Doctoral Innovation Fund Program of Southwest Jiaotong University(No.D-CX201830).
文摘Wire arc additive manufacturing(WAAM)technology has been used to fabricate the multi-layer single-pass deposited wall of AZ80M magnesium(Mg)alloy by gas tungsten arc welding.The formability,thermal cycles,microstructural evolution and mechanical properties of the WAAM AZ80M Mg alloy were investigated.The results show that there was significant difference in the temperature variation and the geometries between the original several layers and the subsequent deposited layers.Owing to the arc energy input,the interpass temperature rised rapidly and then stabilized at 150℃.As a result,the width of the deposited wall increased and then kept stable.There were obvious differences in the microstructure of the WAAM AZ80M Mg alloy among the top zone,intermediate zone and bottom zone of deposited wall.During the arc deposition process,theβphase of the WAAM AZ80M Mg alloy redissolved due to the cyclic heat accumulation,and then precipitated in the grain boundary.The cyclic heat accumulation also led to weakening of dendrite segregation.From the substrate to the top zone,the hardness of the deposited wall decreased gradually,and the intermediate zone which was the main body of deposited wall had relatively uniform hardness.The tensile properties of the WAAM AZ80M Mg alloy were different between the vertical direction and the horizontal direction.And the maximum ultimate tensile strength of the WAAM AZ80M Mg alloy was 308 MPa which was close to that of the as-extruded AZ80M Mg alloy.
基金the China Scholarship Council[grant numbers:201907000039],the National Key Research and Development Plan of China[grant number 2017YFB0305905]The authors acknowledge the financial support from the 2020 open projects[grant numbers:KLATM202003]of Key laboratory of Advanced Technologies of Materials,Ministry of Education China,Southwest Jiaotong University。
文摘To maximize the benefits of wire arc additive manufacturing(WAAM)processes,the effect of post-deposition heat treatment on the microstructure and mechanical properties of WAAM AZ80M magnesium(Mg)alloy was investigated.Three different heat treatment procedures(T4,T5 and T6)were performed.According to the results,after T4 heat treatment,the microsegregation of alloying elements was improved with the eutectic structure dissolved.Samples after T5 heat treatment inherited the net-like distribution of secondary phases similar to the as-deposited sample,where the eutectic structure covering the interdendritic regions and theβ-phase precipitated around the eutectic structure.After T6 heat treatment,the tinyβ-phases re-precipitated from the matrix and distributed in inner and outer of the grains.The hardness distribution of the samples went through T4 and T6 heat treatment was more uniform in comparison to that of T5 heat treated samples.The tensile test showed that the T6 heat treatment improved the strength and ductility,and the anisotropy between horizontal and vertical can be eliminated.Moreover,T4 treated samples exhibited highest ductility.
基金support from China Scholarship Council(No.202107000038)the Na-tional Natural Science Foundation of China(52004227).
文摘In this study,the nano-TiC/AZ61 composites with different heterogeneous bimodal grain(HBG)structures and uniform structure are obtained by regulating the extrusion speed.The effect of HBG structure on the mechanical properties of the composites is investigated.The increasing ductility and toughening mechanism of HBG magnesium matrix composites are carefully discussed.When the extrusion speed increases from 0.75 mm/s to 2.5 mm/s or 3.5 mm/s,the microstructure transforms from uniform to HBG structure.Compared with Uniform-0.75 mm/s composite,Heterogeneous-3.5 mm/s composite achieves a 116.7%increase in ductility in the plastic deformation stage and almost no reduction in ultimate tensile strength.This is mainly because the lower plastic deformation inhomogeneity and higher strain hardening due to hetero-deformation induced(HDI)hardening.Moreover,Heterogeneous-3.5 mm/s composite achieves a 108.3%increase in toughness compared with the Uniform-0.75 mm/s composite.It is mainly because coarse grain(CG)bands can capture and blunt cracks,thereby increasing the energy dissipation for crack propagation and improving toughness.In addition,the CG band of the Heterogeneous-3.5 mm/s composite with larger grain size and lower dislocation density is more conducive to obtaining higher strain hardening and superior blunting crack capability.Thus,the increased ductility and toughness of the Heterogeneous-3.5 mm/s composite is more significant than that Heterogeneous-2.5 mm/s composite.
基金supported by the U.S.Department of Energy’s Office of Energy Efficiency and Renewable Energy(EERE)under the Solar Energy Technologies Office Award Number 38456.
文摘With the continual deployment of power-electronics-interfaced renewable energy resources,increasing privacy concerns due to deregulation of electricity markets,and the diversification of demand-side activities,traditional knowledge-based power system dynamic modeling methods are faced with unprecedented challenges.Data-driven modeling has been increasingly studied in recent years because of its lesser need for prior knowledge,higher capability of handling large-scale systems,and better adaptability to variations of system operating conditions.This paper discusses about the motivations and the generalized process of datadriven modeling,and provides a comprehensive overview of various state-of-the-art techniques and applications.It also comparatively presents the advantages and disadvantages of these methods and provides insight into outstanding challenges and possible research directions for the future.
文摘The Mesoproterozoic rifts are developed in the Ordos Basin located in the western margin of the North China Plate.Based on the latest 3D seismic data and previous research results,this study intends to discuss the zonal differential deformation characteristics and genetic mechanism of the Mesoproterozoic rifts in the Ordos Basin.NE-trending rifts are developed in the Mesoproterozoic in the south-central Ordos Basin,the main part of which are located near the western margin of the North China Plate.NNW-trending rifts are developed in the north of the basin,while NW-NNW rifts in the Mesoproterozoic in Hangjinqi area.The genetic mechanism of the Mesoproterozoic rifts is related to regional extensional stress field,plate boundary conditions and internal preexisting structures.The main extensional stress direction strikes NWW-SSE(120°)in the western margin of the North China Plate,based on the forward rift trend of the northern Mesoproterozoic.In Hangjinqi area,the reactivation of the existing NWtrending Wulansu fault and NW-NW-trending Daolao fault,results in dextral shear stress field.The boundary between the western margin of the North China Plate and its adjacent plates forms a nearly NS-trending preexisting basement tectonic belt,which intersects with the NWW-SSE(120°)extensional stress at an acute angle of 60°.Therefore,the western margin of the North China Plate is formed by oblique normal faults under oblique extension.Due to the long time span of Columbia Supercontinent breakup(1.8e1.6 Ga),the oblique rift in the south-central Ordos Basin is formed under the continuous oblique extension at the western margin of the North China Plate.
文摘Schedule management is the crucial capability for large-scale coal mining investors to successful finish the construction project, which could get by the accumulation of the long-time institutional executive force and ability training. By using factor analysis and validation analysis, extracted control factors of schedule management from data have been made in large coal mine construction companies. Some control factors have a greater influence on the schedule management which are the system factor, measures factor, economic controlling factor, behavioral factor, process factor, organization factor, thus the enterprise schedule management system should include the terms of the above factors.
基金supported by the National Natural Science Foundation of China(81920108029,82303622)the Key Foundation for Social Development Project of the Jiangsu Province,China(BE2021741)。
文摘Triple-negative breast cancer(TNBC),the most aggressive subtype of breast cancer,notably lacks effective treatment strategies.Although androgen receptor(AR)has emerged as a potential therapeutic target for TNBC,monotherapy with AR inhibitors has proven to be of restricted efficacy.Aiming to develop superior therapeutic approaches,a comprehensive drug library screening was conducted.The ERK inhibitor GDC-0994 exhibited significant synergistic effects with the AR inhibitor bicalutamide.Transcriptome sequencing showed that this combination therapy activates ferroptosis,as evidenced by elevated ROS,increased Fe^(2+) levels,a reduced GSH/GSSG ratio,and lipid peroxide accumulation(MDA and 4-HNE).FOXC2 was identified as a key mediator of this synergy.Specifically,the combination therapy inhibits FOXC2-driven EMT and induces ferroptosis via the FOXC2-Hippo signaling axis,suppressing tumor proliferation,migration,and invasion.In summary,this study uncovers the value of AR/ERK co-targeting in TNBC,which might potentiate the development of novel targeted therapeutic strategies in TNBC.
基金supported by the National Natural Science Foundation of China(Nos.52571157,52171125 and 52301152)Sichuan Science and Technology Program(No.2024NSFSC0193).
文摘Plastic strain in polycrystalline metals is highly localized in grain boundaries(GBs),slip bands(SBs)and twins.While extensive research has focused on intra-granular deformation mechanisms such as slip and twinning,strain localization at GBs has been largely overlooked.In this study,high-resolution digital image correlation(HRDIC)was employed to capture the strain distribution and its evolution during tension in an extruded pure Mg sheet.Particular attention was paid to strain localization at GBs and its governing factors.Results reveal that,at 3%applied strain,approximately 10%of GBs were categorized as extremely-high-strain GBs(defined as the GB where at least 20 data points have an effective shear strain(ε_(eff))value exceeding the 99th percentile of the overallεeff distribution),and the majority(84%)of them were observed to deform at even 0.5%applied strain.This suggests that early-stage deformation plays a critical role in subsequent GB strain localization.The mean strain value and grain boundary sliding(GBS)displacement of GBs increased significantly with applied strain,with progressively accelerating increasing rates observed in most instances.Most(~62%)GBs exhibiting slip transfer showed low strain,while a small fraction(~8%)of them exhibited extremely high strain.This indicates that slip transfer can mitigate GB strain localization in most cases.However,complex local conditions are also critical,and case-by-case analysis is essential.Moreover,GBs with misorientation angles ranging from 50°to 80°were found to be more likely to exhibit extremely high strain.This work provides valuable insights into GB strain localization,which is critical for further understanding the plastic deformation of polycrystalline Mg.
基金supported by grants from the Key International Cooperation of the National Natural Science Foundation of China(No.81920108029)the Key Foundation for Social Development Project of the Jiangsu Province,China(No.BE2021741)Youth Fund of the National Natural Science Foundation of China(No.82002783)
文摘Background:Triple-negative breast cancer(TNBC)is an aggressive type of breast cancer associated with poor prognosis and limited treatment options.The androgen receptor(AR)has emerged as a potential therapeutic target for luminal androgen receptor(LAR)TNBC.However,multiple studies have claimed that anti-androgen therapy for AR-positive TNBC only has limited clinical benefits.This study aimed to investigate the role of AR in TNBC and its detailed mechanism.Methods:Immunohistochemistry and TNBC tissue sections were applied to investigate AR and nectin cell adhesion molecule 4(NECTIN4)expression in TNBC tissues.Then,in vitro and in vivo assays were used to explore the function of AR and estrogen receptor beta(ERβ)in TNBC.Chromatin immunoprecipitation sequencing(ChIP-seq),co-immunoprecipitation(co-IP),molecular docking method,and luciferase reporter assay were performed to identify key molecules that affect the function of AR.Results:Based on the TNBC tissue array analysis,we revealed that ERβand AR were positive in 21.92%(32/146)and 24.66%(36/146)of 146 TNBC samples,respectively,and about 13.70%(20/146)of TNBC patients were ERβpositive and AR positive.We further demonstrated the pro-tumoral effects of AR on TNBC cells,however,the oncogenic biology was significantly suppressed when ERβtransfection in LAR TNBC cell lines but not in AR-negative TNBC.Mechanistically,we identified that NECTIN4 promoter–42 bp to–28 bp was an AR response element,and that ERβinteracted with AR thus impeding the AR-mediated NECTIN4 transcription which promoted epithelial–mesenchymal transition in tumor progression.Conclusions:This study suggests that ERβfunctions as a suppressor mediating the effect of AR in TNBC prognosis and cell proliferation.Therefore,our current research facilitates a better understanding of the role and mechanisms of AR in TNBC carcinogenesis.
基金supported by the Key INTERNATIONAL COOPERATION of the National Natural Science Foundation of China(No.81920108029,China)the Key Foundation for Social Development Project of the Jiangsu Province,China(No.BE2021741,China).
文摘Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize with enzalutamide,a second-generation AR inhibitor,in TNBC.By using a strategy for screening drug combinations based on the Sensitivity Index(SI),we found that MK-8776,a selective checkpoint kinase1(CHK1)inhibitor,showed favorable synergism with enzalutamide in AR-positive TNBC.The combination of enzalutamide and MK-8776 was found to exert more significant anti-tumor effects in TNBC than the single application of enzalutamide or MK-8776,respectively.Furthermore,a nanoparticle-based on hyaluronic acid(HA)-modified hollow-manganese dioxide(HMnO_(2)),named HMnE&M@H,was established to encapsulate and deliver enzalutamide and MK-8776.This HA-modified nanosystem managed targeted activation via pH/glutathione responsiveness.HMnE&M@H repressed tumor growth more obviously than the simple addition of enzalutamide and MK-8776 without a carrier.Collectively,our study elucidated the synergy of enzalutamide and MK-8776 in TNBC and developed a novel tumor-targeted nano drug delivery system HMnE&M@H,providing a potential therapeutic approach for the treatment of TNBC.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62072309 and 6171101225).
文摘Activity hijacking is one of the most powerful attacks in Android. Though promising, all the prior activity hijacking attacks suffer from some limitations and have limited attack capabilities. They no longer pose security threats in recent Android due to the presence of effective defense mechanisms. In this work, we propose the first automated and adaptive activity hijacking attack, named VenomAttack, enabling a spectrum of customized attacks (e.g., phishing, spoofing, and DoS) on a large scale in recent Android, even the state-of-the-art defense mechanisms are deployed. Specifically, we propose to use hotpatch techniques to identify vulnerable devices and update attack payload without re-installation and re-distribution, hence bypassing offline detection. We present a newly-discovered flaw in Android and a bug in derivatives of Android, each of which allows us to check if a target app is running in the background or not, by which we can determine the right attack timing via a designed transparent activity. We also propose an automated fake activity generation approach, allowing large-scale attacks. Requiring only the common permission INTERNET, we can hijack activities at the right timing without destroying the GUI integrity of the foreground app. We conduct proof-of-concept attacks, showing that VenomAttack poses severe security risks on recent Android versions. The user study demonstrates the effectiveness of VenomAttack in real-world scenarios, achieving a high success rate (95%) without users’ awareness. That would call more attention to the stakeholders like Google.
基金supported by the China Agriculture Research SystemofMOF andMARA(NO.CARS-21)the College Students Innovation and Entrepreneurship Training Project of Inner MongoliaMedical University(202310132039).
文摘Objective:To ensure the quality of Perilla frutescens(L.)Britt.and improve the associated benefits for stakeholders,this study analyzed the influences of different circulation channels and stakeholders on the quality,price,and other factors of P.frutescens with consideration to P.frutescens distribution.Method:We interviewed the local stakeholders and e-commerce platforms in Oroqen Autonomous Banner and Morin Dawa Daur Autonomous Banner regarding the origin,circulation,distribution,and prices of different medicinal parts of P.frutescens.In addition,the maximumentropymodel was used to predict the potential distribution of P.frutescens in the study area.According to the Chinese Pharmacopeia(2020 edition),we measured the content of index components in the collected Perillae Folium,Perillae Caulis,and Perillae Fructus samples and evaluated the quality of the samples by quantitative and cluster analyses.Remote sensing was employed to distinguish and calculate the P.frutescens area in highly suitable regions.The autoregressive integrated moving average model was adopted to analyze the Perillae Fructus price in the study area.Result:The results showed 8 value chains for P.frutescens.The cooperation chain between farmers and enterprises in the study area could maximize the benefits for all stakeholders and guarantee the quality of the medicinal materials.The results of the regionalization analysis showed that themost suitable area for planting P.frutescens was the junction between Oroqen Autonomous Banner and Morin Dawa Daur Autonomous Banner.Chemical results showed that Perillae Fructus and Perillae Caulis samples were unqualified andmostly purchased from e-commerce platforms.We identified 5 land types,among which the cultivated land area was 3247.7501 km2.The price of Perillae Fructus in the study area showed a rising trend,although this trend slowed down.Conclusion:This study involved various links in the production and circulation of medicinal materials from planting to consumption by consumers,which can help to facilitate the future research on any link.The findings help to guarantee the quality of medicinal materials and benefits of all stakeholders and promote the development of the P.frutescens industry in the study area.
