Over the past half-century,significant efforts have been dedicated to the photocatalytic H_(2)production from H_(2)O under UV–visible light irradiation.These endeavors have yielded remarkable results,with efficiency ...Over the past half-century,significant efforts have been dedicated to the photocatalytic H_(2)production from H_(2)O under UV–visible light irradiation.These endeavors have yielded remarkable results,with efficiency levels now approaching near 100%apparent quantum yields,notably utilizing inorganic semiconducting materials such as modified Al-doped SrTiO_(3)photocatalysts.Meanwhile,advancements in organic polymer semiconducting materials,exemplified by g-C_(3)N_(4),have led to substantial improvements in the efficiency of photocatalytic overall water splitting for H_(2)evolution reaction.These improvements,achieved through chemical engineering methods and molecular-level modifications,have resulted in an apparent quantum yield of 69%at 405 nm,accompanied by significant red-shifting of optical absorption to 1400 nm.These developments are presented in chronological order over the past half-century,underscoring the ongoing quest for innovative breakthroughs to enable largescale practical applications of solar hydrogen production.Key considerations in this pursuit include efficiency,stability,cost-effectiveness,and the independent evolution of H_(2)and O_(2).展开更多
HPPD(4-hydroxyphenylpyruvate dioxygenase)inhibitor are widely used in agriculture due to their high efficacy and environmental friendliness.However,many important crops,such as rice,wheat,and soybean,are naturally sen...HPPD(4-hydroxyphenylpyruvate dioxygenase)inhibitor are widely used in agriculture due to their high efficacy and environmental friendliness.However,many important crops,such as rice,wheat,and soybean,are naturally sensitive to these herbicides.In this study,we employed a directed evolution strategy to enhance the metabolic capacity of OsHSL2,OsHSL4,OsHSL6,and SbHSL1 proteins toward HPPD inhibitors,providing a new technological approach as well as theoretical foundation for molecular breeding of herbicide-resistant crops.By combining AlphaFold 3 protein models with crystal structures,we systematically redesigned key residues to resemble the active residues found in HIS1.Catalytic activity assays demonstrated that specific mutations significantly improved the metabolic activity of HSLs proteins toward various HPPD inhibitors.Notably,the OsHSL2-M4 mutant exhibited enhanced metabolic activity for BBC-OH and methyl-benquitrione,while the OsHSL4-M5 mutant completely metabolized BBC-OH and topramezone.Additionally,the SbHSL1-M4 mutant showed significant improvement in the metabolism of BBC-OH and several other herbicides,providing strong evidence to support the use of structure-guided HSL mutations to enhance crop resistance to HPPD inhibitors.展开更多
Graphitic carbon nitride(g-CN)stands out as the most promising candidate for solar energy conversion owing to its easy preparation,metal-free nature,flexible molecular structure,moderate bandgap,and excellent thermal/...Graphitic carbon nitride(g-CN)stands out as the most promising candidate for solar energy conversion owing to its easy preparation,metal-free nature,flexible molecular structure,moderate bandgap,and excellent thermal/chemical stability.To enhance the performance of intrinsic g-CN,a supramolecular self-assembly strategy has been proposed to regulate the molecular structure of supramolecular precursors through non-covalent interactions across molecular building blocks,thereby optimizing the electronic structure of g-CN.This review provides a comprehensive overview of the recent progress in supramolecular self-assembly-derived graphitic carbon nitride(SM-CN)from both experimental and theoretical computational research in synthesis strategies,including synthesis methods and influencing factors,providing a theoretical foundation for the design of supramolecular assembly.It also discusses modification strategies,such as internal modification of the conjugated plane,interlayer optimization,and construction of heterointerfaces to improve the electronic structure of SM-CN owing to its unique layered structure.This review further summarizes the applications of SM-CN in environment and energy,including wastewater treatment,sterilization and disinfection/air purification,water splitting,H_(2)O_(2)production,organic synthesis/biomass conversion,CO_(2)reduction,photocatalytic coupling technology.Finally,perspectives and outlooks for the future development of SM-CN aim to inspire further innovation in the design and construction of high-performance SM-CN for broader applications.展开更多
Driven by the global energy transition and carbon neutrality targets,alkaline water electrolysis has emerged as a key technology for coupling variable renewable generation with clean hydrogen production,offering consi...Driven by the global energy transition and carbon neutrality targets,alkaline water electrolysis has emerged as a key technology for coupling variable renewable generation with clean hydrogen production,offering considerable potential for absorbing surplus power and enhancing grid flexibility.However,conventional control architectures typically treat the power converter and electrolyzer as independent units,neglecting their dynamic interactions and thereby limiting overall system performance under practical operating conditions.This review critically examines existing control approaches,ranging from classical proportional-integral schemes to model predictive control,fuzzy-logic algorithms,and data-driven methods,evaluating their effectiveness in managing dynamic response,multivariable coupling,and operational constraints as well as their inherent limitations.Attention is then focused on the performance requirements of the hydrogen-production converter,including current ripple suppression,rapid transient response,adaptive thermal regulation,and stable power delivery.An integrated co‑control framework is proposed,aligning converter output with electrolyzer demand across steady-state operation,variable renewable input,and emergency shutdown scenarios to achieve higher efficiency,extended equipment lifetime,and enhanced operational safety.Finally,prospects for advancing unified control methodologies are outlined,with emphasis on constraint-aware predictive control,machine-learning-enhanced modeling,and real‑time co‑optimization for future alkaline electrolyzer systems.展开更多
The corrosion resistance of base metal,laser-arc hybrid welded AZ31B magnesium alloys with and without addition of carbon nanotubes(CNTs)was compared.The corrosion behaviors and the underlying improvement mechanism of...The corrosion resistance of base metal,laser-arc hybrid welded AZ31B magnesium alloys with and without addition of carbon nanotubes(CNTs)was compared.The corrosion behaviors and the underlying improvement mechanism of CNTs were systematically investigated.The introduction of CNTs effectively refined the grains,weakened the texture and enhanced the microstructure homogeneity of the weld,which contributed to the enhancement of corrosion resistance.Specifically,the corrosion rates of hydrogen evolution and weight loss of weld decreased by>30%after the addition of CNTs,and the corrosion products were denser due to the formation of Al_(2)O_(3)passive film.The corrosion current density and polarization resistance of weld with addition of CNTs were 1.220μA/cm^(2)and 7155·cm^(2),respectively,in contrast to 2.480μA/cm^(2)and approximately 269.5·cm^(2)for the weld without CNTs.Besides,the content of precipitates in the weld increased from 0.60%to 1.76%after the addition of CNTs,which can release Al^(3+)ions,promoting the formation of a dense Al_(2)O_(3)film that serves to protect the metal matrix from further degradation.展开更多
Carbon dots(CDs)have been widely studied since their discovery because of simple preparation,low toxicity and excellent luminescence properties.With the deepening of research,the luminescence properties of CDs are not...Carbon dots(CDs)have been widely studied since their discovery because of simple preparation,low toxicity and excellent luminescence properties.With the deepening of research,the luminescence properties of CDs are not only limited to fluorescence,but also their afterglow properties have been widely studied.Many excellent results have been reported for afterglow CDs.Researchers have found that various organic matrixes(OMs)can fix the emission properties of CDs and provide a rigid environment,and the interaction between OMs and CDs can inhibit the non-radiative transition of triplet excitons,which can effectively activate the afterglow performance of CDs.In this review,we provide a detailed introduction to the research progress on afterglow CDs in OMs.The preparation of afterglow CDs and their related properties were analyzed and summarized based on organic polymer matrixes and organic small molecule matrixes.Organic polymer matrixes from synthetic polymers and natural polymers have been introduced.Then,the mechanism of solid and liquid afterglow of CDs by OMs is analyzed,and their applications in the fields of anti-counterfeiting,information encryption,phosphorescence detection,fingerprint recognition,lighting and so on are summarized.Finally,the challenges facing afterglow CDs in OMs are summarized,and future research is proposed.展开更多
As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naph...As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.展开更多
Soil contaminated with heavy metals is a global health hazard.Nanomaterials,with their unique physical and chemical properties,hold significant potential for the remediation of soil polluted with heavy metals.They eff...Soil contaminated with heavy metals is a global health hazard.Nanomaterials,with their unique physical and chemical properties,hold significant potential for the remediation of soil polluted with heavy metals.They effectively reduce the mobility and bioavailability of heavy metals through various mechanisms such as adsorption,precipitation,and oxidation-reduction.This paper provides an in-depth exploration of the cuttingedge applications of various nanomaterials,including nanometallic,nano non-metallic materials,nanoclay and mineral materials,and nano modified biochar materials,in the remediation of heavy metal-contaminated soils.It specifically focuses on the key factors influencing the remediation efficacy of these nanomaterials,as well as the underlying remediation mechanisms and methods for performance optimization.The aims of this paper are to provide guidance for the further application of nanomaterials in the field of soil heavy metal remediation,and to offer insights that could promote the effective control of soil heavy metal pollution.展开更多
Developing efficient catalysts is pivotal for advancing MgH_(2)-based hydrogen storage systems.In this study,a novel catalyst,graphene oxide-supported oxygen vacancy-rich Co_(3)O_(4)and Ni nanoparticles(Ni-OV-C@GO),wa...Developing efficient catalysts is pivotal for advancing MgH_(2)-based hydrogen storage systems.In this study,a novel catalyst,graphene oxide-supported oxygen vacancy-rich Co_(3)O_(4)and Ni nanoparticles(Ni-OV-C@GO),was synthesized to enhance the hydrogen storage performance of MgH_(2).The catalyst dramatically improved the kinetics of MgH_(2),lowering the initial hydrogen desorption temperature of Ni-OV-C@GO-MgH_(2)-7 to 438 K,which is 386 K lower than that of as-milled MgH_(2).The composite achieved 5.0 wt%hydrogen absorption at 423 K within 600 s and retained 97.3%capacity after 30 cycles.Notably,the activation energy for H_(2)desorption was reduced to 40.78 kJ/mol,an 80%decrease compared to pristine MgH_(2).The in-situ formation of CoMg_(2)/CoMg_(2)H_(5)and Mg_(2)Ni/Mg_(2)NiH_(4)acted as“hydrogen pumps”,facilitating multiple hydrogen transfer pathways.Additionally,oxygen vacancies elongated Mg-H bonds,enhancing dehydrogenation kinetics through catalytic effects.These findings provide valuable insights into improving hydrogen adsorption and desorption kinetics in MgH_(2)-based systems.展开更多
Computer analysis of electrocardiograms(ECGs)was introduced more than 50 years ago,with the aim to improve efficiency and clinical workflow.[1,2]However,inaccuracies have been documented in the literature.[3,4]Researc...Computer analysis of electrocardiograms(ECGs)was introduced more than 50 years ago,with the aim to improve efficiency and clinical workflow.[1,2]However,inaccuracies have been documented in the literature.[3,4]Research indicates that emergency department(ED)clinician interruptions occur every 4-10 min,which is significantly more common than in other specialties.[5]This increases the cognitive load and error rates and impacts patient care and clinical effi ciency.[1,2,5]De-prioritization protocols have been introduced in certain centers in the United Kingdom(UK),removing the need for clinician ECG interpretation where ECGs have been interpreted as normal by the machine.展开更多
Osteoarthritis(OA)is a prevalent degenerative joint disorder marked by chronic pain,inflammation,and cartilage loss,with current treatments limited to symptom relief.G protein-coupled receptors(GPCRs)play a pivotal ro...Osteoarthritis(OA)is a prevalent degenerative joint disorder marked by chronic pain,inflammation,and cartilage loss,with current treatments limited to symptom relief.G protein-coupled receptors(GPCRs)play a pivotal role in OA progression by regulating inflammation,chondrocyte survival,and matrix homeostasis.However,their multifaceted signaling,via G proteins orβ-arrestins,poses challenges for precise therapeutic targeting.Biased agonism,where ligands selectively activate specific GPCR pathways,emerges as a promising approach to optimize efficacy and reduce side effects.This review examines biased signaling in OAassociated GPCRs,including cannabinoid receptors(CB1,CB2),chemokine receptors(CCR2,CXCR4),protease-activated receptors(PAR-2),adenosine receptors(A1R,A2AR,A2BR,A3R),melanocortin receptors(MC1R,MC3R),bradykinin receptors(B2R),prostaglandin E2 receptors(EP-2,EP-4),and calcium-sensing receptors(CaSR).We analyze ligands in clinical trials and explore natural products from Traditional Chinese Medicine as potential biased agonists.These compounds,with diverse structures and bioactivities,offer novel therapeutic avenues.By harnessing biased agonism,this review underscores the potential for developing targeted,safer OA therapies that address its complex pathology,bridging molecular insights with clinical translation.展开更多
Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the ...Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the process of precipitation and distribution of precipitates. Deformation-induced defects exert significant impacts on the precipitation and already present precipitates, which however is often overlooked. In this study, the interactions between deformation and precipitation/precipitates, and their impacts on mechanical properties were systematically investigated in the solution-treated (ST) Al-0.61Mg-1.17Si-0.5Cu (wt.%), processed by multi-pass equal channel angular pressing (ECAP) and thermal treatments. Novel deformation-mediated cyclic evolution of precipitates is discovered: ST→ (1,2 passes: deformation induced precipitation) Guinier Preston (GP) zones→ (An250/30) Q’ and L phases→ (3-pass: deformation induced fragmentation/resolution) spherical precipitates→ (4-pass: deformation induced further fragmentation/resolution) GP zones. On this basis, we extend the quasi-binary phase diagram of Al-Mg_(2)Si along deformation as the third dimension and construct an innovative defect phase diagram for the Al-Mg-Si-based system. To testify to the effect of deformation-mediated cyclic evolution of precipitation/precipitates on the optimum mechanical properties, peak-aging treatments were performed in samples of ST and 3-pass states. Based on the microscopic characterizations, a distinctive mechanism of peak-aging strengthening is proposed. Notably in the 3-pass ECAPed and peak-aged sample the dominant strengthening phases become the L precipitates that thrived from the segmented and spherical L phases, rather than β’’ precipitates in the solely peak-aged ST sample. Our work provides a feasible example for exploring the combined processing technique of multi-step deformation and thermal treatments, to optimize the mechanical properties.展开更多
MgH_(2)is a promising solid-state hydrogen storage material.However,its high thermodynamics and sluggish kinetics hinder its practical application.Catalytic strategy is effective in improving its kinetic performance.N...MgH_(2)is a promising solid-state hydrogen storage material.However,its high thermodynamics and sluggish kinetics hinder its practical application.Catalytic strategy is effective in improving its kinetic performance.Nevertheless,the highly efficient catalysts or additives are normally of low-yield in fabrication with high cost.In this work,a novel structural LaVO_(4)fabricated by a low-cost method of spraying dry followed by a calcination is used as a catalytic additive for the hydrogen storage of MgH_(2).With an optimized addition of LaVO_(4),the overall hydrogen storage performances of MgH_(2)are significantly improved.An onset dehydrogenation temperature of only 183℃is obtained after an initial activation of dehydrogenation and hydrogenation.The system can desorb 5.7 wt%H_(2)at 250℃within 10 min and maintains a dehydrogenation capacity of 5.0 wt%H_(2)after 50 cycles.It is found that LaVO_(4)is transferred to lanthanum hydride and metallic vanadium in the initial dehydrogenation process,the former acts as a highly effective catalyst for the hydrogen storage of MgH_(2)and the latter undergoes reversible hydrogenation and dehydrogenation in the subsequent cycles.The structural design of the catalyst and its scalable fabrication are highly valuable in realizing the practical application of catalytic strategy for the hydrogen storage of MgH_(2).展开更多
1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain bounda...1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].展开更多
Rapeseed is the primary domestic source of edible vegetable oil in China.Its oil is naturally rich in phytosterols,polyphenols,tocopherols,carotenoids and other lipid-soluble companions,which are highly beneficial to ...Rapeseed is the primary domestic source of edible vegetable oil in China.Its oil is naturally rich in phytosterols,polyphenols,tocopherols,carotenoids and other lipid-soluble companions,which are highly beneficial to human health.Since the content and bioaccessibility of these health-promoting companions are mostly locked during the first post-harvest operation,the pretreatment technology has become the decisive lever for simultaneously maximizing oil yield and nutritional value.This review critically synthesizes recent findings on how rapeseed pretreatment modulates its signature lipid companions,contrasts conventional roasting with emerging pulsed-electric field,microwave and steam-explosion technologies,and evaluates their respective impacts on extraction efficiency,structural integrity and functional performance on phytosterols,polyphenols,tocopherols and carotenoids.It particularly compares and analyzes the extraction efficiency,cost-effectiveness,and environmental impact for these emerging technologies,and discusses the prospects for their integrated applications.Furthermore,the review concludes with the current research trends in pretreatment technology and offers insights into future research directions,aiming to provide scientific guidance for the high-quality processing of rapeseed and the production of rapeseed oil with high nutritional value.展开更多
The thiol-imidazole functionalized(p-triphenyl-pentafluorobenzaldehyde)polymer(IMPTP)was prepared and quaternized with different side chains to obtain imidazolium-modified Me-IMPTP,He-IMPTP and BIM-IMPTP membranes for...The thiol-imidazole functionalized(p-triphenyl-pentafluorobenzaldehyde)polymer(IMPTP)was prepared and quaternized with different side chains to obtain imidazolium-modified Me-IMPTP,He-IMPTP and BIM-IMPTP membranes for application in high-temperature proton exchange membrane fuel cells(HT-PEMFCs).The presence of the thioether group in the polymers enabled radical scavenging for antioxidant properties,while imidazolium cations interacted strongly with H_(2)PO_(4) to prevent phosphoric acid(PA)leaching.The prepared BIM-IMPTP membrane incorporating bisimidazolium cation string with a long alkyl spacer demonstrated the highest mass retention of 82.93%after being immersed in Fenton's reagent for 24 h.Additionally,the PA-doped BIM-IMPTP membranes exhibited excellent PA retention under high-humidity conditions(80℃/100%RH).The single cell equipped with the BIM-IMPTP/320%PA membrane achieved a maximum power density(PDmax)of 945 mW cm^(-2)at 160℃.Among the four membranes with a similar acid doping content(ADC),the BIM-IMPTP/163%PA membrane with bis-cation pairs in the side chains exhibited a well-developed microphase-separated structure and high proton conductivity(119.0 mS cm^(-1)at 180℃).The single cell assembled with BIM-IMPTP/163%PA membrane maintained a PDmax of 613 mW cm^(-2)at 160℃ and demonstrated long-term operational stability under both 150/400 mA cm^(-2)and 80℃/200 mA cm^(-2)conditions.These results indicate that the introduction of thioether and bis-cation pairs in the structural design of polymers contributes significantly to the long-term stability of HT-PEMs.展开更多
Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith ...Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith formation critically influences nutrient release,soil production,and long-term climate regulation.Regolith development is governed by two primary processes:production and denudation.An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions.This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region(Sanya,China).We conducted geochemical analyses,encompassing major,trace elements and mineralogical compositions as well as U-series isotopes,and applied the U-series disequilibrium method to investigate the formation history of this profile.Alternatively,dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results,and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith.Utilizing this multi-stage model,regolith production rates is derived from the“gain and loss”model,ranging from 1.27±0.03 to 42.42±24.24 m/Ma.The production rates first increase from surface until a maximum rate is reached at the depth of∼160 cm and then decrease at further deeper horizons along the depth profile,and the variation of production rates follows a so-called“humped function”.This pioneering investigation into regolith production rates in the Chinese tropical region indicates that(1)the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides(^(10)Be_in-situ);(2)subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates;and(3)the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.展开更多
In this study,AZ91D(Mg-9Al-Zn)alloys reinforced with 2 vol%TC4(Ti-6Al-4V)particles fabricated by semi-solid stir casting were extruded at different ratios,resulting in observed grain refinement effects.The research fi...In this study,AZ91D(Mg-9Al-Zn)alloys reinforced with 2 vol%TC4(Ti-6Al-4V)particles fabricated by semi-solid stir casting were extruded at different ratios,resulting in observed grain refinement effects.The research findings demonstrate that both TC4 andβ-Mg_(17)Al_(12) phases contribute to promoting dynamic recrystallization(DRX)nucleation.With increasing extrusion ratio,theβ-phase(Mg_(17)Al_(12))gradually fractures into smaller particles,leading to progressive grain refinement.Furthermore,the transition from〈01-10〉fiber texture to non-basal texture in theα-Mg matrix after hot extrusion is attributed to improved DRX behavior and activation of non-basal slip.As the extrusion ratio increases,the tensile strength and elongation(EL)of TC4_(p)/AZ91D composite improve significantly,reaching optimum comprehensive mechanical properties at an extrusion of 40:1 with a yield strength(YS)of 257 MPa,an ultimate tensile strength(UTS)of 357 MPa,and an EL of 9.7%.This remarkable strengthening effect is primarily attributed toβ-phase reinforcement,grain refinement strengthening,and strain hardening.展开更多
The generation of defects,such as cracks and pores,presents significant challenges for high-strength met-als and alloys fabricated by the quick-emerging additive manufacturing technology,and subsequent post-processing...The generation of defects,such as cracks and pores,presents significant challenges for high-strength met-als and alloys fabricated by the quick-emerging additive manufacturing technology,and subsequent post-processing treatments are often necessary before their practical applications.In this work,a novel heat treatment approach,involving a pre-softening treatment before hot isostatic pressing(HIP),is developed to facilitate the crack-healing in René142 superalloy produced through laser powder bed fusion.Results demonstrate that René142 alloy exhibits a propensity for severe cracking across a wide range of printing parameters,primarily in the form of solidification cracks and liquation cracks.These cracks are formed mainly due to a wide solidification range,the presence of a liquid film,and the concentration of resid-ual stress.The pre-softening solution heat treatment significantly reduces dislocation density and resid-ual stress levels,and the subsequent HIP together leads to a defect-free,dense structure for René142 superalloy.Consequently,the René142 alloy processed by the pre-softening HIP treatment achieves an excellent combination of yield strength(850 MPa),ultimate tensile strength(1227 MPa),and elongation(13.7%),with pseudo-equiaxed grains(120-150μm)and squareγ'precipitates(approximately 540 nm).These findings provide valuable insights for exploring crack elimination methods in other nickel-based superalloys fabricated through additive manufacturing.展开更多
In the present study,three layers of aluminum(Al)and a single layer of copper(Cu)were joined by resistance rolling welding(RRW)and the impact of welding velocity on microstructure,mechanical property and electrical pr...In the present study,three layers of aluminum(Al)and a single layer of copper(Cu)were joined by resistance rolling welding(RRW)and the impact of welding velocity on microstructure,mechanical property and electrical property was investigated.The results showed that the welding velocity was identified as the most significant parameter.With decreasing the welding velocity from 11 mm/s to 1 mm/s,the mechanical property of the joints initially showed an increase,reaching a maximum coach-peel peak load of 185.25 N,due to the larger well bonded region,then decreased owing to the high-temperature softening of the base metal.The elec-trical resistance of the joint demonstrated a consistent varying,characterized by an initial decrease owing to the larger completely bonded region and then increased with the decreasing welding velocity due to the excessive generation of Al2Cu with high electrical resistance.A cooling system was thus utilized to reduce the welding temperature to relieve the high-temperature softening,that suc-cessfully improved the welding quality of the joint by an 11.5%increase in the coach-peel peak load.展开更多
文摘Over the past half-century,significant efforts have been dedicated to the photocatalytic H_(2)production from H_(2)O under UV–visible light irradiation.These endeavors have yielded remarkable results,with efficiency levels now approaching near 100%apparent quantum yields,notably utilizing inorganic semiconducting materials such as modified Al-doped SrTiO_(3)photocatalysts.Meanwhile,advancements in organic polymer semiconducting materials,exemplified by g-C_(3)N_(4),have led to substantial improvements in the efficiency of photocatalytic overall water splitting for H_(2)evolution reaction.These improvements,achieved through chemical engineering methods and molecular-level modifications,have resulted in an apparent quantum yield of 69%at 405 nm,accompanied by significant red-shifting of optical absorption to 1400 nm.These developments are presented in chronological order over the past half-century,underscoring the ongoing quest for innovative breakthroughs to enable largescale practical applications of solar hydrogen production.Key considerations in this pursuit include efficiency,stability,cost-effectiveness,and the independent evolution of H_(2)and O_(2).
基金supported by the National Key Research and Development Program of China(No.2024YFE0214300)Hubei Provincial Science and Technology Plan Project(2022BEC051)selfdetermined research funds of CCNU from the colleges'basic research and operation of MOE(No.CCNU24JCPT023).
文摘HPPD(4-hydroxyphenylpyruvate dioxygenase)inhibitor are widely used in agriculture due to their high efficacy and environmental friendliness.However,many important crops,such as rice,wheat,and soybean,are naturally sensitive to these herbicides.In this study,we employed a directed evolution strategy to enhance the metabolic capacity of OsHSL2,OsHSL4,OsHSL6,and SbHSL1 proteins toward HPPD inhibitors,providing a new technological approach as well as theoretical foundation for molecular breeding of herbicide-resistant crops.By combining AlphaFold 3 protein models with crystal structures,we systematically redesigned key residues to resemble the active residues found in HIS1.Catalytic activity assays demonstrated that specific mutations significantly improved the metabolic activity of HSLs proteins toward various HPPD inhibitors.Notably,the OsHSL2-M4 mutant exhibited enhanced metabolic activity for BBC-OH and methyl-benquitrione,while the OsHSL4-M5 mutant completely metabolized BBC-OH and topramezone.Additionally,the SbHSL1-M4 mutant showed significant improvement in the metabolism of BBC-OH and several other herbicides,providing strong evidence to support the use of structure-guided HSL mutations to enhance crop resistance to HPPD inhibitors.
基金supported by the National Natural Science Foundation of China(NSFC No.52271228)the Natural Science Foundation of Shaanxi Province(No.2023-JC-ZD-21)the Doctoral Dissertation Innovation Fund of Xi'an University of Technology(No.101-252072301)。
文摘Graphitic carbon nitride(g-CN)stands out as the most promising candidate for solar energy conversion owing to its easy preparation,metal-free nature,flexible molecular structure,moderate bandgap,and excellent thermal/chemical stability.To enhance the performance of intrinsic g-CN,a supramolecular self-assembly strategy has been proposed to regulate the molecular structure of supramolecular precursors through non-covalent interactions across molecular building blocks,thereby optimizing the electronic structure of g-CN.This review provides a comprehensive overview of the recent progress in supramolecular self-assembly-derived graphitic carbon nitride(SM-CN)from both experimental and theoretical computational research in synthesis strategies,including synthesis methods and influencing factors,providing a theoretical foundation for the design of supramolecular assembly.It also discusses modification strategies,such as internal modification of the conjugated plane,interlayer optimization,and construction of heterointerfaces to improve the electronic structure of SM-CN owing to its unique layered structure.This review further summarizes the applications of SM-CN in environment and energy,including wastewater treatment,sterilization and disinfection/air purification,water splitting,H_(2)O_(2)production,organic synthesis/biomass conversion,CO_(2)reduction,photocatalytic coupling technology.Finally,perspectives and outlooks for the future development of SM-CN aim to inspire further innovation in the design and construction of high-performance SM-CN for broader applications.
基金supported by Natural Science Foundation of Shanghai,under the Shanghai Action Plan for Science,Technology and Innovation(22ZR1464800).
文摘Driven by the global energy transition and carbon neutrality targets,alkaline water electrolysis has emerged as a key technology for coupling variable renewable generation with clean hydrogen production,offering considerable potential for absorbing surplus power and enhancing grid flexibility.However,conventional control architectures typically treat the power converter and electrolyzer as independent units,neglecting their dynamic interactions and thereby limiting overall system performance under practical operating conditions.This review critically examines existing control approaches,ranging from classical proportional-integral schemes to model predictive control,fuzzy-logic algorithms,and data-driven methods,evaluating their effectiveness in managing dynamic response,multivariable coupling,and operational constraints as well as their inherent limitations.Attention is then focused on the performance requirements of the hydrogen-production converter,including current ripple suppression,rapid transient response,adaptive thermal regulation,and stable power delivery.An integrated co‑control framework is proposed,aligning converter output with electrolyzer demand across steady-state operation,variable renewable input,and emergency shutdown scenarios to achieve higher efficiency,extended equipment lifetime,and enhanced operational safety.Finally,prospects for advancing unified control methodologies are outlined,with emphasis on constraint-aware predictive control,machine-learning-enhanced modeling,and real‑time co‑optimization for future alkaline electrolyzer systems.
基金supported by the National Natural Science Foundation of China(grant nos.52275364 and 52025052)。
文摘The corrosion resistance of base metal,laser-arc hybrid welded AZ31B magnesium alloys with and without addition of carbon nanotubes(CNTs)was compared.The corrosion behaviors and the underlying improvement mechanism of CNTs were systematically investigated.The introduction of CNTs effectively refined the grains,weakened the texture and enhanced the microstructure homogeneity of the weld,which contributed to the enhancement of corrosion resistance.Specifically,the corrosion rates of hydrogen evolution and weight loss of weld decreased by>30%after the addition of CNTs,and the corrosion products were denser due to the formation of Al_(2)O_(3)passive film.The corrosion current density and polarization resistance of weld with addition of CNTs were 1.220μA/cm^(2)and 7155·cm^(2),respectively,in contrast to 2.480μA/cm^(2)and approximately 269.5·cm^(2)for the weld without CNTs.Besides,the content of precipitates in the weld increased from 0.60%to 1.76%after the addition of CNTs,which can release Al^(3+)ions,promoting the formation of a dense Al_(2)O_(3)film that serves to protect the metal matrix from further degradation.
基金the Youth Talent Program Startup Foundation of Qufu Normal University(No.602601)the Natural Science Foundation of Rizhao(No.RZ2021ZR37)the Natural Science Foundation of Shandong(No.ZR2022MB047)。
文摘Carbon dots(CDs)have been widely studied since their discovery because of simple preparation,low toxicity and excellent luminescence properties.With the deepening of research,the luminescence properties of CDs are not only limited to fluorescence,but also their afterglow properties have been widely studied.Many excellent results have been reported for afterglow CDs.Researchers have found that various organic matrixes(OMs)can fix the emission properties of CDs and provide a rigid environment,and the interaction between OMs and CDs can inhibit the non-radiative transition of triplet excitons,which can effectively activate the afterglow performance of CDs.In this review,we provide a detailed introduction to the research progress on afterglow CDs in OMs.The preparation of afterglow CDs and their related properties were analyzed and summarized based on organic polymer matrixes and organic small molecule matrixes.Organic polymer matrixes from synthetic polymers and natural polymers have been introduced.Then,the mechanism of solid and liquid afterglow of CDs by OMs is analyzed,and their applications in the fields of anti-counterfeiting,information encryption,phosphorescence detection,fingerprint recognition,lighting and so on are summarized.Finally,the challenges facing afterglow CDs in OMs are summarized,and future research is proposed.
基金support of the National Natural Science Foundation of China(Nos.22378369 and 22205207)Major Project of Natural Science Foundation of Zhejiang Province(LD24B060001).
文摘As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.
基金the Natural Science Research Initiation Fund Project of China West Normal University(No.23KE001)the National Natural Science Foundation of China(Nos.42407186,42277033,and 42171045)+1 种基金the Basic Research Foundation of Yunnan Province(No.202401AT070304)the Central Public-interest Scientific Institution Basal Research Fund(No.Y2024QC28)for their financial support。
文摘Soil contaminated with heavy metals is a global health hazard.Nanomaterials,with their unique physical and chemical properties,hold significant potential for the remediation of soil polluted with heavy metals.They effectively reduce the mobility and bioavailability of heavy metals through various mechanisms such as adsorption,precipitation,and oxidation-reduction.This paper provides an in-depth exploration of the cuttingedge applications of various nanomaterials,including nanometallic,nano non-metallic materials,nanoclay and mineral materials,and nano modified biochar materials,in the remediation of heavy metal-contaminated soils.It specifically focuses on the key factors influencing the remediation efficacy of these nanomaterials,as well as the underlying remediation mechanisms and methods for performance optimization.The aims of this paper are to provide guidance for the further application of nanomaterials in the field of soil heavy metal remediation,and to offer insights that could promote the effective control of soil heavy metal pollution.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4003200)Nature Science Foundation of Guangxi(Grant No.2024GXNSFDA010044)the National Natural Science Foundation of China(Grant Nos.52101245,U20A20237,U24A2044).
文摘Developing efficient catalysts is pivotal for advancing MgH_(2)-based hydrogen storage systems.In this study,a novel catalyst,graphene oxide-supported oxygen vacancy-rich Co_(3)O_(4)and Ni nanoparticles(Ni-OV-C@GO),was synthesized to enhance the hydrogen storage performance of MgH_(2).The catalyst dramatically improved the kinetics of MgH_(2),lowering the initial hydrogen desorption temperature of Ni-OV-C@GO-MgH_(2)-7 to 438 K,which is 386 K lower than that of as-milled MgH_(2).The composite achieved 5.0 wt%hydrogen absorption at 423 K within 600 s and retained 97.3%capacity after 30 cycles.Notably,the activation energy for H_(2)desorption was reduced to 40.78 kJ/mol,an 80%decrease compared to pristine MgH_(2).The in-situ formation of CoMg_(2)/CoMg_(2)H_(5)and Mg_(2)Ni/Mg_(2)NiH_(4)acted as“hydrogen pumps”,facilitating multiple hydrogen transfer pathways.Additionally,oxygen vacancies elongated Mg-H bonds,enhancing dehydrogenation kinetics through catalytic effects.These findings provide valuable insights into improving hydrogen adsorption and desorption kinetics in MgH_(2)-based systems.
文摘Computer analysis of electrocardiograms(ECGs)was introduced more than 50 years ago,with the aim to improve efficiency and clinical workflow.[1,2]However,inaccuracies have been documented in the literature.[3,4]Research indicates that emergency department(ED)clinician interruptions occur every 4-10 min,which is significantly more common than in other specialties.[5]This increases the cognitive load and error rates and impacts patient care and clinical effi ciency.[1,2,5]De-prioritization protocols have been introduced in certain centers in the United Kingdom(UK),removing the need for clinician ECG interpretation where ECGs have been interpreted as normal by the machine.
基金supported by the National Key R&D Program of the Ministry of Science and Technology(2023YFC2509900)National Natural Science Foundation of China(82374106)+3 种基金National Natural Science Foundation of China(U22A20371)the Basic and Applied Basic Research Fund of Guangdong Province(2021B1515120061)the Shenzhen Science and Technology Innovation Committee(JCYJ20210324102006017)SZ-HK Joint Laboratory for Innovative Biomaterials under CAS-HK Joint Laboratories(2024-2028).
文摘Osteoarthritis(OA)is a prevalent degenerative joint disorder marked by chronic pain,inflammation,and cartilage loss,with current treatments limited to symptom relief.G protein-coupled receptors(GPCRs)play a pivotal role in OA progression by regulating inflammation,chondrocyte survival,and matrix homeostasis.However,their multifaceted signaling,via G proteins orβ-arrestins,poses challenges for precise therapeutic targeting.Biased agonism,where ligands selectively activate specific GPCR pathways,emerges as a promising approach to optimize efficacy and reduce side effects.This review examines biased signaling in OAassociated GPCRs,including cannabinoid receptors(CB1,CB2),chemokine receptors(CCR2,CXCR4),protease-activated receptors(PAR-2),adenosine receptors(A1R,A2AR,A2BR,A3R),melanocortin receptors(MC1R,MC3R),bradykinin receptors(B2R),prostaglandin E2 receptors(EP-2,EP-4),and calcium-sensing receptors(CaSR).We analyze ligands in clinical trials and explore natural products from Traditional Chinese Medicine as potential biased agonists.These compounds,with diverse structures and bioactivities,offer novel therapeutic avenues.By harnessing biased agonism,this review underscores the potential for developing targeted,safer OA therapies that address its complex pathology,bridging molecular insights with clinical translation.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20187,52171007,52371111,and 52371177).
文摘Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the process of precipitation and distribution of precipitates. Deformation-induced defects exert significant impacts on the precipitation and already present precipitates, which however is often overlooked. In this study, the interactions between deformation and precipitation/precipitates, and their impacts on mechanical properties were systematically investigated in the solution-treated (ST) Al-0.61Mg-1.17Si-0.5Cu (wt.%), processed by multi-pass equal channel angular pressing (ECAP) and thermal treatments. Novel deformation-mediated cyclic evolution of precipitates is discovered: ST→ (1,2 passes: deformation induced precipitation) Guinier Preston (GP) zones→ (An250/30) Q’ and L phases→ (3-pass: deformation induced fragmentation/resolution) spherical precipitates→ (4-pass: deformation induced further fragmentation/resolution) GP zones. On this basis, we extend the quasi-binary phase diagram of Al-Mg_(2)Si along deformation as the third dimension and construct an innovative defect phase diagram for the Al-Mg-Si-based system. To testify to the effect of deformation-mediated cyclic evolution of precipitation/precipitates on the optimum mechanical properties, peak-aging treatments were performed in samples of ST and 3-pass states. Based on the microscopic characterizations, a distinctive mechanism of peak-aging strengthening is proposed. Notably in the 3-pass ECAPed and peak-aged sample the dominant strengthening phases become the L precipitates that thrived from the segmented and spherical L phases, rather than β’’ precipitates in the solely peak-aged ST sample. Our work provides a feasible example for exploring the combined processing technique of multi-step deformation and thermal treatments, to optimize the mechanical properties.
基金supported by the National Natural Science Foundation of PR China(Nos.52071287,52125104 and 52072342)Natural Science Foundation of Zhejiang Province,PR China(No.LZ23E010002).
文摘MgH_(2)is a promising solid-state hydrogen storage material.However,its high thermodynamics and sluggish kinetics hinder its practical application.Catalytic strategy is effective in improving its kinetic performance.Nevertheless,the highly efficient catalysts or additives are normally of low-yield in fabrication with high cost.In this work,a novel structural LaVO_(4)fabricated by a low-cost method of spraying dry followed by a calcination is used as a catalytic additive for the hydrogen storage of MgH_(2).With an optimized addition of LaVO_(4),the overall hydrogen storage performances of MgH_(2)are significantly improved.An onset dehydrogenation temperature of only 183℃is obtained after an initial activation of dehydrogenation and hydrogenation.The system can desorb 5.7 wt%H_(2)at 250℃within 10 min and maintains a dehydrogenation capacity of 5.0 wt%H_(2)after 50 cycles.It is found that LaVO_(4)is transferred to lanthanum hydride and metallic vanadium in the initial dehydrogenation process,the former acts as a highly effective catalyst for the hydrogen storage of MgH_(2)and the latter undergoes reversible hydrogenation and dehydrogenation in the subsequent cycles.The structural design of the catalyst and its scalable fabrication are highly valuable in realizing the practical application of catalytic strategy for the hydrogen storage of MgH_(2).
基金support by the National Natural Science Foundation of China(Grant Nos.U23A20546 and 52271010)the Chinese National Natural Science Fund for Distinguished Young Scholars(Grant No.52025015)the Natural Science Foundation of Tianjin City(No.21JCZDJC00510).
文摘1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].
基金funded by National Key R&D Program Key Special Project(Grant No.2024YFF1106100)National Natural Science Foundation of China(Grant No.32472446 and 22301313)+4 种基金Hubei Provincial Technology Innovation Project(Grant No.2024BBB084)Hubei Provincial Science and Technology Project(Grant No.2025BBB065)Innovation group project of Hubei Province(Grant No.2023AFA042)Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(Grant No.CAAS-ASTIP-2021-OCRI)Hubei Young sci-tech Talen Funding Project(E Kexieban 2025[67])。
文摘Rapeseed is the primary domestic source of edible vegetable oil in China.Its oil is naturally rich in phytosterols,polyphenols,tocopherols,carotenoids and other lipid-soluble companions,which are highly beneficial to human health.Since the content and bioaccessibility of these health-promoting companions are mostly locked during the first post-harvest operation,the pretreatment technology has become the decisive lever for simultaneously maximizing oil yield and nutritional value.This review critically synthesizes recent findings on how rapeseed pretreatment modulates its signature lipid companions,contrasts conventional roasting with emerging pulsed-electric field,microwave and steam-explosion technologies,and evaluates their respective impacts on extraction efficiency,structural integrity and functional performance on phytosterols,polyphenols,tocopherols and carotenoids.It particularly compares and analyzes the extraction efficiency,cost-effectiveness,and environmental impact for these emerging technologies,and discusses the prospects for their integrated applications.Furthermore,the review concludes with the current research trends in pretreatment technology and offers insights into future research directions,aiming to provide scientific guidance for the high-quality processing of rapeseed and the production of rapeseed oil with high nutritional value.
基金supported by the National Natural Science Foundation of China(No.22179047)the Development of Scientific and Technological Project of Jilin Province(20230201139GX).
文摘The thiol-imidazole functionalized(p-triphenyl-pentafluorobenzaldehyde)polymer(IMPTP)was prepared and quaternized with different side chains to obtain imidazolium-modified Me-IMPTP,He-IMPTP and BIM-IMPTP membranes for application in high-temperature proton exchange membrane fuel cells(HT-PEMFCs).The presence of the thioether group in the polymers enabled radical scavenging for antioxidant properties,while imidazolium cations interacted strongly with H_(2)PO_(4) to prevent phosphoric acid(PA)leaching.The prepared BIM-IMPTP membrane incorporating bisimidazolium cation string with a long alkyl spacer demonstrated the highest mass retention of 82.93%after being immersed in Fenton's reagent for 24 h.Additionally,the PA-doped BIM-IMPTP membranes exhibited excellent PA retention under high-humidity conditions(80℃/100%RH).The single cell equipped with the BIM-IMPTP/320%PA membrane achieved a maximum power density(PDmax)of 945 mW cm^(-2)at 160℃.Among the four membranes with a similar acid doping content(ADC),the BIM-IMPTP/163%PA membrane with bis-cation pairs in the side chains exhibited a well-developed microphase-separated structure and high proton conductivity(119.0 mS cm^(-1)at 180℃).The single cell assembled with BIM-IMPTP/163%PA membrane maintained a PDmax of 613 mW cm^(-2)at 160℃ and demonstrated long-term operational stability under both 150/400 mA cm^(-2)and 80℃/200 mA cm^(-2)conditions.These results indicate that the introduction of thioether and bis-cation pairs in the structural design of polymers contributes significantly to the long-term stability of HT-PEMs.
基金supported by The National Natural Science Foundation of China(42303060)The China Scholarship Council(CSC,201906250131).
文摘Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith formation critically influences nutrient release,soil production,and long-term climate regulation.Regolith development is governed by two primary processes:production and denudation.An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions.This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region(Sanya,China).We conducted geochemical analyses,encompassing major,trace elements and mineralogical compositions as well as U-series isotopes,and applied the U-series disequilibrium method to investigate the formation history of this profile.Alternatively,dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results,and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith.Utilizing this multi-stage model,regolith production rates is derived from the“gain and loss”model,ranging from 1.27±0.03 to 42.42±24.24 m/Ma.The production rates first increase from surface until a maximum rate is reached at the depth of∼160 cm and then decrease at further deeper horizons along the depth profile,and the variation of production rates follows a so-called“humped function”.This pioneering investigation into regolith production rates in the Chinese tropical region indicates that(1)the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides(^(10)Be_in-situ);(2)subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates;and(3)the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.
基金the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)the Guangdong Provincial Academy of Sciences Fund(2020GDASYL-20200101001)the Natural Science Foundation of Hubei Province,China(2023AFB1033).
文摘In this study,AZ91D(Mg-9Al-Zn)alloys reinforced with 2 vol%TC4(Ti-6Al-4V)particles fabricated by semi-solid stir casting were extruded at different ratios,resulting in observed grain refinement effects.The research findings demonstrate that both TC4 andβ-Mg_(17)Al_(12) phases contribute to promoting dynamic recrystallization(DRX)nucleation.With increasing extrusion ratio,theβ-phase(Mg_(17)Al_(12))gradually fractures into smaller particles,leading to progressive grain refinement.Furthermore,the transition from〈01-10〉fiber texture to non-basal texture in theα-Mg matrix after hot extrusion is attributed to improved DRX behavior and activation of non-basal slip.As the extrusion ratio increases,the tensile strength and elongation(EL)of TC4_(p)/AZ91D composite improve significantly,reaching optimum comprehensive mechanical properties at an extrusion of 40:1 with a yield strength(YS)of 257 MPa,an ultimate tensile strength(UTS)of 357 MPa,and an EL of 9.7%.This remarkable strengthening effect is primarily attributed toβ-phase reinforcement,grain refinement strengthening,and strain hardening.
基金support of the National Natural Science Foundation of China(Project Nos.52371012 and 52301060).
文摘The generation of defects,such as cracks and pores,presents significant challenges for high-strength met-als and alloys fabricated by the quick-emerging additive manufacturing technology,and subsequent post-processing treatments are often necessary before their practical applications.In this work,a novel heat treatment approach,involving a pre-softening treatment before hot isostatic pressing(HIP),is developed to facilitate the crack-healing in René142 superalloy produced through laser powder bed fusion.Results demonstrate that René142 alloy exhibits a propensity for severe cracking across a wide range of printing parameters,primarily in the form of solidification cracks and liquation cracks.These cracks are formed mainly due to a wide solidification range,the presence of a liquid film,and the concentration of resid-ual stress.The pre-softening solution heat treatment significantly reduces dislocation density and resid-ual stress levels,and the subsequent HIP together leads to a defect-free,dense structure for René142 superalloy.Consequently,the René142 alloy processed by the pre-softening HIP treatment achieves an excellent combination of yield strength(850 MPa),ultimate tensile strength(1227 MPa),and elongation(13.7%),with pseudo-equiaxed grains(120-150μm)and squareγ'precipitates(approximately 540 nm).These findings provide valuable insights for exploring crack elimination methods in other nickel-based superalloys fabricated through additive manufacturing.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB3407400)the National Natural Science Foundation of China(Grant No.52475386,Grant No.52025058).
文摘In the present study,three layers of aluminum(Al)and a single layer of copper(Cu)were joined by resistance rolling welding(RRW)and the impact of welding velocity on microstructure,mechanical property and electrical property was investigated.The results showed that the welding velocity was identified as the most significant parameter.With decreasing the welding velocity from 11 mm/s to 1 mm/s,the mechanical property of the joints initially showed an increase,reaching a maximum coach-peel peak load of 185.25 N,due to the larger well bonded region,then decreased owing to the high-temperature softening of the base metal.The elec-trical resistance of the joint demonstrated a consistent varying,characterized by an initial decrease owing to the larger completely bonded region and then increased with the decreasing welding velocity due to the excessive generation of Al2Cu with high electrical resistance.A cooling system was thus utilized to reduce the welding temperature to relieve the high-temperature softening,that suc-cessfully improved the welding quality of the joint by an 11.5%increase in the coach-peel peak load.
