Cotton,a crucial commercial fibre crop,depends heavily on seed-associated characteristics like germination rate,vigour,and resistance to post-harvest deterioration for both production and lint quality.Serious cellular...Cotton,a crucial commercial fibre crop,depends heavily on seed-associated characteristics like germination rate,vigour,and resistance to post-harvest deterioration for both production and lint quality.Serious cellular damage dur-ing post-harvest processes such as delinting,prolonged seedling emergence periods,decreased viability,increased susceptibility to infections,and lipid peroxidation during storage pose serious problems to seed quality.The perfor-mance of seeds and total crop productivity are adversely affected by these problems.Traditional methods of seed improvement,like physical scarification and seed priming,have demonstrated promise in raising cotton seed vigour and germination rates.Furthermore,modern approaches including plasma therapies,magnetic water treatments,and nanotechnology-based treatments have shown promise in improving seed quality and reducing environmen-tal stresses.By offering sustainable substitutes for conventional approaches,these cutting-edge procedures lessen the need for fungicides and other agrochemicals that pollute the environment.This review explores various con-ventional and emerging strategies to address the detrimental factors impacting cotton seed quality.It emphasizes the importance of integrating classical and advanced approaches to enhance germination,ensure robust crop estab-lishment,and achieve higher yields.In addition to promoting sustainable cotton production,this kind of integration helps preserve the ecosystem and create resilient farming methods.展开更多
The pronounced anisotropy in mechanical properties presents a major obstacle to the extensive application of aluminum-lithium(Al-Li)alloys,primarily attributed to heterogeneous precipitate distribution,grain structure...The pronounced anisotropy in mechanical properties presents a major obstacle to the extensive application of aluminum-lithium(Al-Li)alloys,primarily attributed to heterogeneous precipitate distribution,grain structure variations,and crystallographic texture.This study investigates the impact of pre-thermal treatment prior to hot rolling and aging treatment on the anisotropy of mechanical properties of 2195 alloy sheet fabricated by gas atomization,hot pressing and hot rolling.The results demonstrate that pre-treatment at 450℃for 4 h promotes finer and more uniform distribution of precipitates,effectively mitigating mechanical anisotropy of the alloy sheet.Additionally,this treatment facilitates recrystallization during hot rolling,further reducing mechanical anisotropy.The in-plane anisotropy(IPA)factors for ultimate tensile strength(UTS)and yield strength(YS)are 1.15%and 0.77%,respectively.Subsequent aging treatment enhances grain refinement and the uniformity of the T_(1) phase,suppresses the formation of precipitation-free zones(PFZs),significantly improving the strength and toughness of the alloy sheet.After peak aging at 165℃for 48 h,the alloy sheet exhibits YS of 547 MPa,UTS of 590 MPa,and elongation(EL)of 7.7%.展开更多
Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discu...Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discussed.It is found that after the addition of Sn promoter,the specific surface area and the generation of active CoB phase are increased,while the oxidation treatment of CNTs results in more loading amounts of active components and enrichment of electron at active sites as well as large surface area.Consequently,the Sn-doped CoB catalysts supported on CNTs with oxidation treatment exhibits a significantly improved activity with a high H_(2)generation rate of 2640 mL/(min·g).Meanwhile,this catalyst shows a low activation energy of 43.7 kJ/mol and relatively high reusability.展开更多
Kang et al.published a research article on the treatment of ischemic stroke using engineered Treg cells(Kang et al.,Prog Biochem Biophys,2025,52(4):946-956.DOI:10.16476/j.pibb.2025.0019).Their study mainly explores th...Kang et al.published a research article on the treatment of ischemic stroke using engineered Treg cells(Kang et al.,Prog Biochem Biophys,2025,52(4):946-956.DOI:10.16476/j.pibb.2025.0019).Their study mainly explores the immunoregulatory role of regulatory T(Treg)cells in ischemic stroke,providing an innovative therapeutic strategy.Neuroinflammation is a major driver of secondary injury after stroke.Existing treatments focus on vascular recanalization while neglecting immune regulation.Their study proposes to modulate neuroinflammation through in vitro-induced Treg cells,offering a novel approach distinct from traditional thrombolysis and endovascular interventions.展开更多
The microstructures,mechanical properties,and fracture behaviors of an Al-5.9Zn-1.9Mg alloy subjected to thermomechanical treatment across different pre-rolling temperatures have been exhaustively investigated in pres...The microstructures,mechanical properties,and fracture behaviors of an Al-5.9Zn-1.9Mg alloy subjected to thermomechanical treatment across different pre-rolling temperatures have been exhaustively investigated in present work.The pre-deformation temperature exerts a modest influence on grain morphology,while it profoundly impacts the dislocation configurations and precipitation behaviors.Elevating the rolling temperature from ambient to 170℃results in a reduction in dislocation density within grains accompanied by a notable enhancement in their distributional uniformity.While advancing the temperature to 320℃prompts the premature formation of precipitates during deformation,which diminishes the precipitation during the subsequent ageing.Tensile results reveal that the thermomechanical treatment incorporating pre-rolling at 170℃confers a substantial strengthening effect on the alloy on the basis of both grain boundary strengthening and dislocation strengthening stemmed from pre-deformation along with the precipitation strengthening generated by ageing.Furthermore,the microstructure exhibits a relatively scarce presence of inhomogeneous features such as dislocation pile-ups and micro shear bands,contributing favorably to enhance the ductility of the alloy that presents the mixture of cleavage fracture and dimple-induced failure.展开更多
In this study,samples obtained from 1.3343 high-speed steel punches with TiN coatings were tested.The samples were subjected to heat treatment at different cryogenic temperatures(<196℃)and durations(12,24 and 36 h...In this study,samples obtained from 1.3343 high-speed steel punches with TiN coatings were tested.The samples were subjected to heat treatment at different cryogenic temperatures(<196℃)and durations(12,24 and 36 h),followed by tempering at two different temperatures(200,500℃).For performance testing,a ball-on-disk wear test setup was utilized and a total of 6 groups of samples were examined.The effects of cryo-treatment and tempering on microstructure were revealed through microstructural analysis with scanning electron microscopy(SEM),X-ray(XRD diffraction),and Rietveld analysis.Additionally,the hardness of the punches was measured with microhardness measurements.The optimal wear resistance was observed in the 36 h deep cryo-treated and 200℃tempered samples.The characterization study indicates that by cryogenic treatment a significant portion of the retained austenite transformed into martensite and secondary carbides formed,resulting in improved wear resistance and a slight increase in hardness.展开更多
Electroshocking treatment(EST),an efficient and rapid material treatment method,promotes microstructure evolution and improves mechanical properties.This study incorporates EST into the conventional cold rolling-quenc...Electroshocking treatment(EST),an efficient and rapid material treatment method,promotes microstructure evolution and improves mechanical properties.This study incorporates EST into the conventional cold rolling-quenching tempering process of M50 steel and investigates the influence and mechanism of applying EST at different stages of the process on the microstructure and mechanical properties.Scanning electron microscope(SEM),transmission electron microscope(TEM),and X-ray diffraction(XRD)were used to characterize the effect of EST on microstructure.The results show that EST can refine the grains of M50(average reduction of 10.1%in grain size),homogenize the grain size distribution,reduce the dislocation density(20.9%in average),promote the dissolution of carbides in the matrix and distribute them more uniformly along the grain boundaries,resulting in the improvement of mechanical properties.The mechanical properties of the specimen with the process flow of rolling-quenching-tempering-electroshocking showed excellent performance,with an increase in hardness of 1.4%,tensile strength of 17.7%,and elongation at break of 24.3%as compared to the specimen without EST.The tensile properties of the specimen with the process flow of rolling electroshocking-quenching-tempering showed the best performance,with an increase in tensile strength of 30.0%and elongation at break of 30.7%as compared to the specimen without EST.展开更多
It is of great significance to study the corrosion process of aluminum(Al)alloys fasteners in order to mitigate corrosion for their widespread applications.In this paper,a method for enhancing the corrosion resistance...It is of great significance to study the corrosion process of aluminum(Al)alloys fasteners in order to mitigate corrosion for their widespread applications.In this paper,a method for enhancing the corrosion resistance of Al alloy fasteners is proposed.7075 Al alloy parts with a fine-grained microstructure were prepared by pre-heat treatment(PHT),combined subsequent equal channel angular pressing(ECAP)and cold upsetting(CU).The corrosion behavior of the specimens was investigated by intergranular corrosion and electrochemical test.Microstructure investigations were carried out by field emission scanning electron microscopy,energy dispersive spectrometer and transmission electron microscopy.The relationship between microstructural evolution and corrosion resistance changes was also explored.The results show that both PHT and ECAP-CU significantly improved the corrosion resistance of the samples and modified the corrosion process.The open circuit potential,corrosion current density and corrosion rate of the alloy on electrochemical test were(-0.812±8.854)×10^(-5) V(vs.SCE),(6.379±0.025)×10^(-6) A/cm^(2) and 0.066 mm/year,respectively,and the intergranular corrosion depth was(557±8)μm.The main factor controlling the corrosion behavior was the microstructure evolution.After PHT,the disappearance of the dendritic structure and the dissolution of the nonequilibrium second phase eliminated the potential difference between the phases,reducing the free energy in the as cast state.When ECAP-CU was used after PHT,the grain refinement was accompanied by a high density of grain boundaries and dislocations,which led to the formation of a denser passivation film on the alloy surface,improving the corrosion resistance in an aggressive environment.展开更多
In the present study,the mechanical and ballistic properties of friction stir welded(FSW)aluminum alloy(AA5754)samples were investigated,both untreated and cryogenically treated,when impacted by a 7.62 mm armour-pierc...In the present study,the mechanical and ballistic properties of friction stir welded(FSW)aluminum alloy(AA5754)samples were investigated,both untreated and cryogenically treated,when impacted by a 7.62 mm armour-piercing(AP)bullet at an impact velocity of 682±20 m/s.The FSW technique was used to prepare the welded samples for AA5754,with an axial force of 7 kN,a feed rate of 20 mm/min,and a speed of 1200 rpm.The cryogenic treatments performed after welding,including deep cryogenic treatment(DCT)at196℃ and shallow cryogenic treatment(SCT)at80℃,for 6 and 72 h,respectively.The microstructure and mechanical characteristics of cryogenically treated and untreated joints were examined.The cryogenic treatment refined the grain size(1.05 μm)and enhanced the microhardness(93 Hv).Moreover,DCT-FSW significantly improved the tensile strength(13.93%)and impact strength(8.45%)compared to untreated FSW sample.Additionally,in untreated FSW samples,the fracture behaviour varied:the impact fracture mode primarily exhibited ductile failure,while the tensile fracture exhibited a mixed fracture mode.In contrast,the tensile and impact fracture modes of the DCT-FSWwere dominated by a ductile failure mode.The DCT-FSW target demonstrated a lower depth of penetration(DOP)of 31 mm compared to the SCT-FSWand untreated FSW targets.Post-ballistic SEM analysis in the crater region of all three zones revealed the formation of frictional grooves,small cracks,and adiabatic shear bands(ASBs).展开更多
Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the...Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the impact of nitric acid oxidation on the surface of carbonized melamine foam and its microwave absorption properties.The treated foam exhibits optimal reflection loss of−21.51 dB at 13.20 GHz,with an effective absorption bandwidth of 7.04 GHz.The enhanced absorption properties are primarily attributed to the strengthened dielectric loss,improved impedance matching,and increased polarization losses resulting from the oxidized surfaces.This research demonstrates a promising new approach for research into surface treatments to improve the performances of microwave absorbers.展开更多
This study examines the effects of friction stir welding(FSW)and post-weld heat treatment(PWHT)on the grain boundary character distribution and corrosion resistance of cross sectional(top and bottom)regions of nickel-...This study examines the effects of friction stir welding(FSW)and post-weld heat treatment(PWHT)on the grain boundary character distribution and corrosion resistance of cross sectional(top and bottom)regions of nickel-and molybdenum-free high-nitrogen austenitic stainless steel(HNASS).FSW at 400 rpm and 30 mm/min resulted in finer grains(4.18μm)and higher coincident site lattice(CSL)boundaries(32.3%)at the top of the stir zone(SZ)due to dynamic recrystallization(DRX).PWHT at 900℃for 1 h led to grain coarsening(12.91μm the bottom SZ)but enhanced CSL boundaries from 24.6%to 30.2%,improving grain boundary stability.PWHT reduced the kernel average misorientation(KAM)by 14.9%in the SZ-top layer and 20.4%in the SZ-bottom layer,accompanied by a 25%decrease in hardness in the SZ-top layer and 26.7%in the SZ-bottom layer,indicating strain recovery and reduced dislocation density.Potentiodynamic polarization tests(PDP)showed a 18%increase in pitting potential and a 76%reduction in corrosion rate after PWHT.The improvement in corrosion resistance is attributed to the increase inΣ3 twin boundaries,which enhance grain boundary stability and reduce susceptibility to localized corrosion.These findings highlight the role of PWHT in refining the microstructure and strengthening corrosion resistance,making HNASS a promising material for demanding applications.展开更多
A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m3/d is conducted combined with a demonstration project. The systematical researches on the effi...A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m3/d is conducted combined with a demonstration project. The systematical researches on the efficiency of combined operation conditions of anaerobic-aerobic and anaerobic-aerobic-flocculation as well as chemical phosphorus removal of hypersaline mustard wastewater are conducted. The optimal operation condition and parameters in pretreatment of mustard wastewater in winter （the water temperature ranges 8-15 ~C） are determined： the anaerobic load is 3.0 kg （COD）/（m3.d）, the average COD and phosphate concentration of the inflow are respectively 3 883 mg/L and 35.53 mg/L and the dosage of flocculent （PAC） is 400 mg/L. The anaerobic-aerobic-flocculation combined operation condition and postpositive phosphorous removal with ferrous sulfate are employed. After treatment, the COD of the effluent is 470 mg/L and the average phosphate concentration is 5.09 mg/L. The effluent could achieve the third-level of Integrated Wastewater Discharge Standard （GB 8978--1996）.展开更多
To improve the microstructure and properties of the electron beam welded joints, the vacuum or furnace whole post weld heat treatment (FWPWHT) usually should be done on it. The electron beam local post weld heat treat...To improve the microstructure and properties of the electron beam welded joints, the vacuum or furnace whole post weld heat treatment (FWPWHT) usually should be done on it. The electron beam local post weld heat treatment (EBLPWHT) is a rather new heat treatment procedure that provides the advantages of high precision, flexibility and efficiency, energy saving and higher productivity. In this paper, the microstructure, mechanical properties, fracture toughness and fatigue properties of electron beam welded joints of 30CrMnSiNi2A steel in as-welded (AW) and EBLPWHT conditions have been investigated respectively. The results show that the microstructures of different zones of joints in as-welded condition are changed by EBLPWHT procedure, in which the welds from coarse needle martensite into lath-shaped martensite; the main structures of heat affected zones (HAZ) from lath-shaped martensite into lower bainite. The properties of welded joints can be improved by the EBLPWHT in some extent, especially the fracture toughness of the welds and the fatigue crack resistance of welded joints can be sufficiently improved. However, more appropriate heat treatment parameters of the EBLPWHT have to be studied in order to increase the mechanical properties of base metal near by the HAZ.展开更多
The new forming process of AA6061 alloy tube, including solution treatment, granule medium internal high-pressure forming and aging treatment, was developed. The AA6061 alloy tube via heat treatment satisfied the form...The new forming process of AA6061 alloy tube, including solution treatment, granule medium internal high-pressure forming and aging treatment, was developed. The AA6061 alloy tube via heat treatment satisfied the forming requirement, and the granule medium internal high pressure forming method for AA6061 alloy tube was also realized by using convenient implementation with low requirement of equipment and flexible design of product. At a solution temperature of 560℃ and time of 120 min, the elongation of the AA6061 extruded tube increases by 300% and the strength and the hardness dramatically decrease too. Therefore, the AA6061 alloy tube meets the requirement of internal high-pressure forming because of the improvement of formability. The experiments shows that the strength and hardness of AA6061 alloy workpiece recover to that of the as-received alloy at an aging temperature of 180℃ and time of 360 min, and the strength of AA6061 alloy workpiece is equal to the base alloy. The typical parts of convex ring tube, stepped shaft tube and hexagonal tube were successfully produced in lab by using the present forming method. The forming tests show that the maximum expansion ratio(MER) of the AA6061 extruded tube increases by 25.5% and the material properties of formed AA6061 alloy tube reached the performance of as-received alloy.展开更多
A coupled system consisting of an upflow membrane-less microbial fuel cell (upflow ML-MFC) and a photobioreactor was developed, and its effectiveness for continuous wastewater treatment and electricity production was ...A coupled system consisting of an upflow membrane-less microbial fuel cell (upflow ML-MFC) and a photobioreactor was developed, and its effectiveness for continuous wastewater treatment and electricity production was evaluated. Wastewater was fed to the upflow ML-MFC to remove chemical oxygen demand (COD), phosphorus and nitrogen with simultaneous electricity generation. The effluent from the cathode compartment of the upflow ML-MFC was then continuously fed to an external photobioreactor for removing the remaining phosphorus and nitrogen using microalgae. Alone, the upflow ML-MFC produces a maximum power density of 481 mW/m 3 , and obtains 77.9% COD, 23.5% total phosphorus (TP) and 97.6% NH4+-N removals. When combined with the photobioreactor, the system achieves 99.3% TP and 99.0% NH4+-N total removal. These results show both the effectiveness and the potential application of the coupled system to continuously treat domestic wastewater and simultaneously generate electricity and biomass.展开更多
The effects of postweld heat treatment on the microstructure and metallurgical properties of a bronze–carbon steel(st37)explosively bonded interface were studied.Explosive welding was done under 1.5-and 2-mm standoff...The effects of postweld heat treatment on the microstructure and metallurgical properties of a bronze–carbon steel(st37)explosively bonded interface were studied.Explosive welding was done under 1.5-and 2-mm standoff distances and different conditions of explosive charge.Samples were postweld heat treated for 4 and 16 h in the furnace at 250°C and 500°C and then air cooled.Laboratory studies using optical microscopy,scanning electron microscopy,and microhardness testing were used to evaluate the welded samples.Microstructural examinations showed that by increasing the standoff distance and the explosive charge,the interface of bronze to steel became wavier.The microhardness test result showed that the hardness of the samples was higher near the joint interface compared with other areas because of the intensive plastic deformation,which was caused by the explosion force.The results show that increasing the heat treatment temperature and time caused the intermetallic compounds’layer thickness to increase,and,because of the higher diffusion of copper and tin,the iron amount in the intermetallic compounds decreased.Also,because of the increase in heat treatment temperature and time,internal stresses were released,and the interface hardness decreased.展开更多
A new process of AlN removal from secondary aluminum dross(SAD)by pyrometallurgical treatment with added cryolite was applied for solving the problem of recycling the secondary aluminum dross.The response surface meth...A new process of AlN removal from secondary aluminum dross(SAD)by pyrometallurgical treatment with added cryolite was applied for solving the problem of recycling the secondary aluminum dross.The response surface methodology(RSM)was used to design experiments and optimize parameters.The results show that adding the appropriate amount of cryolite can effectively promote the oxidation of AlN in the SAD,and too much cryolite will reduce the promotion effect.The effects of roasting temperature and cryolite on the denitrification rate are the most significant(p<0.0001)followed by holding time.Predicted values of the denitrification rate are found to be in good agreement with experimental values(R^(2)=0.9894 and R_(adj)^(2)=0.9775),which confirms the validity of the model employed.The optimum conditions of roasting temperature of 750°C,holding time of 194 min,mass fraction of cryolite of 17.7%are obtained according to the quadratic model.Under these conditions,the maximum actual denitrification rate reaches 94.71%and the AlN content in the SAD is only 0.55 wt%.The unfired brick with compressive strength of 18.62 MPa(GB/T 2542−2012)was prepared based on the roasted SAD.展开更多
The microstructure and Gd-rich phase evolution of as-cast AZ31-xGd(x=0,1.5 wt.%,2.0 wt.%and 2.5 wt.%)magnesium alloys during semi-solid isothermal heat treatment were investigated deeply in the present work.Results sh...The microstructure and Gd-rich phase evolution of as-cast AZ31-xGd(x=0,1.5 wt.%,2.0 wt.%and 2.5 wt.%)magnesium alloys during semi-solid isothermal heat treatment were investigated deeply in the present work.Results showed that the lamellar(Mg,Al)3Gd phases transformed into the particle-like Al2Gd phases in AZ31 magnesium alloys with Gd addition during semi-solid isothermal heat treatment,leading to yielding more sphericalα-Mg grains.When Gd content is 2.0 wt.%,the size of semi-solid spherical grains reaches the minimum.The main mechanism of grain refinement lies in the remelting of dendritic branches as well as the auxiliary effect of a small number of Al2Gd particles as grain refining inoculants.Meanwhile,Al2Gd particles enriched at the solid-liquid interfaces can remarkably retard the growth rate ofα-Mg grains.A reduction of deformation resistance has been successfully achieved in AZ31-2.0Gd magnesium alloy after semi-solid isothermal heat treatment,which shows a moderate compressive deformation resistance(230 MPa),comparing to the as-cast AZ31 magnesium alloy(280 MPa)and semi-solid AZ31 magnesium alloy(209 MPa).展开更多
Al-Zn-Mg-Sc-Zr alloy samples were annealed to four different states （under-aging, peak-aging, over-aging and double-aging） and then thoroughly investigated by means of electron backscatter diffraction （EBSD）, tran...Al-Zn-Mg-Sc-Zr alloy samples were annealed to four different states （under-aging, peak-aging, over-aging and double-aging） and then thoroughly investigated by means of electron backscatter diffraction （EBSD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, tensile and fatigue crack growth rate tests to explore the influence of annealing treatment on microstmcture and fatigue crack growth behavior. The results indicate that Al3（Sc,Zr） particles can effectively refine grains and enhance tensile properties and fatigue properties. After annealing treatment, the under-aged sample and double-aged sample obtained average grain sizes of 4.9473 and 4.1257 μm, and the maximum value of yield/tensile strength （561 MPa/581 MPa） was obtained in peak-aged state. In the Paris region, fatigue crack growth rate, crack deflection and bifurcation, crack blunting and inter/trans-granular propagation were discussed based on data fitting and Laird model and Griffith theory. And the results show that the under-aged sample possesses the best resistance to fatigue crack propagation and the most tortuous and bifurcated crack path. For all samples, the fatigue crack growth rate in the rupture region was inversely proportional to yield strength.展开更多
基金the Indian Council of Agriculture Research-National Agriculture Higher Education Program(No.A4/003026/2023)to carry out this work during the international faculty training program at Nanyang Technological University,Singapore,under the Institution Development Plan.
文摘Cotton,a crucial commercial fibre crop,depends heavily on seed-associated characteristics like germination rate,vigour,and resistance to post-harvest deterioration for both production and lint quality.Serious cellular damage dur-ing post-harvest processes such as delinting,prolonged seedling emergence periods,decreased viability,increased susceptibility to infections,and lipid peroxidation during storage pose serious problems to seed quality.The perfor-mance of seeds and total crop productivity are adversely affected by these problems.Traditional methods of seed improvement,like physical scarification and seed priming,have demonstrated promise in raising cotton seed vigour and germination rates.Furthermore,modern approaches including plasma therapies,magnetic water treatments,and nanotechnology-based treatments have shown promise in improving seed quality and reducing environmen-tal stresses.By offering sustainable substitutes for conventional approaches,these cutting-edge procedures lessen the need for fungicides and other agrochemicals that pollute the environment.This review explores various con-ventional and emerging strategies to address the detrimental factors impacting cotton seed quality.It emphasizes the importance of integrating classical and advanced approaches to enhance germination,ensure robust crop estab-lishment,and achieve higher yields.In addition to promoting sustainable cotton production,this kind of integration helps preserve the ecosystem and create resilient farming methods.
基金Project(52274369)supported by the National Natural Science Foundation of ChinaProject(623020034)supported by the National Key Laboratory of Science and Technology on High-strength Structural Materials,China。
文摘The pronounced anisotropy in mechanical properties presents a major obstacle to the extensive application of aluminum-lithium(Al-Li)alloys,primarily attributed to heterogeneous precipitate distribution,grain structure variations,and crystallographic texture.This study investigates the impact of pre-thermal treatment prior to hot rolling and aging treatment on the anisotropy of mechanical properties of 2195 alloy sheet fabricated by gas atomization,hot pressing and hot rolling.The results demonstrate that pre-treatment at 450℃for 4 h promotes finer and more uniform distribution of precipitates,effectively mitigating mechanical anisotropy of the alloy sheet.Additionally,this treatment facilitates recrystallization during hot rolling,further reducing mechanical anisotropy.The in-plane anisotropy(IPA)factors for ultimate tensile strength(UTS)and yield strength(YS)are 1.15%and 0.77%,respectively.Subsequent aging treatment enhances grain refinement and the uniformity of the T_(1) phase,suppresses the formation of precipitation-free zones(PFZs),significantly improving the strength and toughness of the alloy sheet.After peak aging at 165℃for 48 h,the alloy sheet exhibits YS of 547 MPa,UTS of 590 MPa,and elongation(EL)of 7.7%.
基金supported by National Natural Science Foundation of China(22276144).
文摘Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discussed.It is found that after the addition of Sn promoter,the specific surface area and the generation of active CoB phase are increased,while the oxidation treatment of CNTs results in more loading amounts of active components and enrichment of electron at active sites as well as large surface area.Consequently,the Sn-doped CoB catalysts supported on CNTs with oxidation treatment exhibits a significantly improved activity with a high H_(2)generation rate of 2640 mL/(min·g).Meanwhile,this catalyst shows a low activation energy of 43.7 kJ/mol and relatively high reusability.
文摘Kang et al.published a research article on the treatment of ischemic stroke using engineered Treg cells(Kang et al.,Prog Biochem Biophys,2025,52(4):946-956.DOI:10.16476/j.pibb.2025.0019).Their study mainly explores the immunoregulatory role of regulatory T(Treg)cells in ischemic stroke,providing an innovative therapeutic strategy.Neuroinflammation is a major driver of secondary injury after stroke.Existing treatments focus on vascular recanalization while neglecting immune regulation.Their study proposes to modulate neuroinflammation through in vitro-induced Treg cells,offering a novel approach distinct from traditional thrombolysis and endovascular interventions.
基金Project(ZZYJKT2025-03) supported by the Project of State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Central South University,ChinaProject(2024YFB3411200) supported by the National Key Research and Development Program of China。
文摘The microstructures,mechanical properties,and fracture behaviors of an Al-5.9Zn-1.9Mg alloy subjected to thermomechanical treatment across different pre-rolling temperatures have been exhaustively investigated in present work.The pre-deformation temperature exerts a modest influence on grain morphology,while it profoundly impacts the dislocation configurations and precipitation behaviors.Elevating the rolling temperature from ambient to 170℃results in a reduction in dislocation density within grains accompanied by a notable enhancement in their distributional uniformity.While advancing the temperature to 320℃prompts the premature formation of precipitates during deformation,which diminishes the precipitation during the subsequent ageing.Tensile results reveal that the thermomechanical treatment incorporating pre-rolling at 170℃confers a substantial strengthening effect on the alloy on the basis of both grain boundary strengthening and dislocation strengthening stemmed from pre-deformation along with the precipitation strengthening generated by ageing.Furthermore,the microstructure exhibits a relatively scarce presence of inhomogeneous features such as dislocation pile-ups and micro shear bands,contributing favorably to enhance the ductility of the alloy that presents the mixture of cleavage fracture and dimple-induced failure.
基金Project supported by the Haier GroupProject supported by the Eskisehir Osmangazi University,Türkiye。
文摘In this study,samples obtained from 1.3343 high-speed steel punches with TiN coatings were tested.The samples were subjected to heat treatment at different cryogenic temperatures(<196℃)and durations(12,24 and 36 h),followed by tempering at two different temperatures(200,500℃).For performance testing,a ball-on-disk wear test setup was utilized and a total of 6 groups of samples were examined.The effects of cryo-treatment and tempering on microstructure were revealed through microstructural analysis with scanning electron microscopy(SEM),X-ray(XRD diffraction),and Rietveld analysis.Additionally,the hardness of the punches was measured with microhardness measurements.The optimal wear resistance was observed in the 36 h deep cryo-treated and 200℃tempered samples.The characterization study indicates that by cryogenic treatment a significant portion of the retained austenite transformed into martensite and secondary carbides formed,resulting in improved wear resistance and a slight increase in hardness.
基金Project(G202403)supported by the Open Foundation of The State Key Laboratory of Refractories and Metallurgy,ChinaProject(2022CFB378)supported by the Natural Science Foundation of Hubei Province,China+2 种基金Project(B 17034)supported by 111 Project,ChinaProject(IRT_17R83)supported by the Innovative Research Team Development Program of Ministry of Education of ChinaProject(P2024-026)supported by the Open Foundation of The State Key Laboratory of Materials Processing and Die&Mould Technology,China。
文摘Electroshocking treatment(EST),an efficient and rapid material treatment method,promotes microstructure evolution and improves mechanical properties.This study incorporates EST into the conventional cold rolling-quenching tempering process of M50 steel and investigates the influence and mechanism of applying EST at different stages of the process on the microstructure and mechanical properties.Scanning electron microscope(SEM),transmission electron microscope(TEM),and X-ray diffraction(XRD)were used to characterize the effect of EST on microstructure.The results show that EST can refine the grains of M50(average reduction of 10.1%in grain size),homogenize the grain size distribution,reduce the dislocation density(20.9%in average),promote the dissolution of carbides in the matrix and distribute them more uniformly along the grain boundaries,resulting in the improvement of mechanical properties.The mechanical properties of the specimen with the process flow of rolling-quenching-tempering-electroshocking showed excellent performance,with an increase in hardness of 1.4%,tensile strength of 17.7%,and elongation at break of 24.3%as compared to the specimen without EST.The tensile properties of the specimen with the process flow of rolling electroshocking-quenching-tempering showed the best performance,with an increase in tensile strength of 30.0%and elongation at break of 30.7%as compared to the specimen without EST.
基金Project(52275350)supported by the National Natural Science Foundation of ChinaProject(0301006)supported by International Cooperative Scientific Research Platform of SUES,China。
文摘It is of great significance to study the corrosion process of aluminum(Al)alloys fasteners in order to mitigate corrosion for their widespread applications.In this paper,a method for enhancing the corrosion resistance of Al alloy fasteners is proposed.7075 Al alloy parts with a fine-grained microstructure were prepared by pre-heat treatment(PHT),combined subsequent equal channel angular pressing(ECAP)and cold upsetting(CU).The corrosion behavior of the specimens was investigated by intergranular corrosion and electrochemical test.Microstructure investigations were carried out by field emission scanning electron microscopy,energy dispersive spectrometer and transmission electron microscopy.The relationship between microstructural evolution and corrosion resistance changes was also explored.The results show that both PHT and ECAP-CU significantly improved the corrosion resistance of the samples and modified the corrosion process.The open circuit potential,corrosion current density and corrosion rate of the alloy on electrochemical test were(-0.812±8.854)×10^(-5) V(vs.SCE),(6.379±0.025)×10^(-6) A/cm^(2) and 0.066 mm/year,respectively,and the intergranular corrosion depth was(557±8)μm.The main factor controlling the corrosion behavior was the microstructure evolution.After PHT,the disappearance of the dendritic structure and the dissolution of the nonequilibrium second phase eliminated the potential difference between the phases,reducing the free energy in the as cast state.When ECAP-CU was used after PHT,the grain refinement was accompanied by a high density of grain boundaries and dislocations,which led to the formation of a denser passivation film on the alloy surface,improving the corrosion resistance in an aggressive environment.
文摘In the present study,the mechanical and ballistic properties of friction stir welded(FSW)aluminum alloy(AA5754)samples were investigated,both untreated and cryogenically treated,when impacted by a 7.62 mm armour-piercing(AP)bullet at an impact velocity of 682±20 m/s.The FSW technique was used to prepare the welded samples for AA5754,with an axial force of 7 kN,a feed rate of 20 mm/min,and a speed of 1200 rpm.The cryogenic treatments performed after welding,including deep cryogenic treatment(DCT)at196℃ and shallow cryogenic treatment(SCT)at80℃,for 6 and 72 h,respectively.The microstructure and mechanical characteristics of cryogenically treated and untreated joints were examined.The cryogenic treatment refined the grain size(1.05 μm)and enhanced the microhardness(93 Hv).Moreover,DCT-FSW significantly improved the tensile strength(13.93%)and impact strength(8.45%)compared to untreated FSW sample.Additionally,in untreated FSW samples,the fracture behaviour varied:the impact fracture mode primarily exhibited ductile failure,while the tensile fracture exhibited a mixed fracture mode.In contrast,the tensile and impact fracture modes of the DCT-FSWwere dominated by a ductile failure mode.The DCT-FSW target demonstrated a lower depth of penetration(DOP)of 31 mm compared to the SCT-FSWand untreated FSW targets.Post-ballistic SEM analysis in the crater region of all three zones revealed the formation of frictional grooves,small cracks,and adiabatic shear bands(ASBs).
基金Project(2023RC3066)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2023JJ50079)supported by the Hunan Provincial Natural Science Foundation,China。
文摘Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the impact of nitric acid oxidation on the surface of carbonized melamine foam and its microwave absorption properties.The treated foam exhibits optimal reflection loss of−21.51 dB at 13.20 GHz,with an effective absorption bandwidth of 7.04 GHz.The enhanced absorption properties are primarily attributed to the strengthened dielectric loss,improved impedance matching,and increased polarization losses resulting from the oxidized surfaces.This research demonstrates a promising new approach for research into surface treatments to improve the performances of microwave absorbers.
文摘This study examines the effects of friction stir welding(FSW)and post-weld heat treatment(PWHT)on the grain boundary character distribution and corrosion resistance of cross sectional(top and bottom)regions of nickel-and molybdenum-free high-nitrogen austenitic stainless steel(HNASS).FSW at 400 rpm and 30 mm/min resulted in finer grains(4.18μm)and higher coincident site lattice(CSL)boundaries(32.3%)at the top of the stir zone(SZ)due to dynamic recrystallization(DRX).PWHT at 900℃for 1 h led to grain coarsening(12.91μm the bottom SZ)but enhanced CSL boundaries from 24.6%to 30.2%,improving grain boundary stability.PWHT reduced the kernel average misorientation(KAM)by 14.9%in the SZ-top layer and 20.4%in the SZ-bottom layer,accompanied by a 25%decrease in hardness in the SZ-top layer and 26.7%in the SZ-bottom layer,indicating strain recovery and reduced dislocation density.Potentiodynamic polarization tests(PDP)showed a 18%increase in pitting potential and a 76%reduction in corrosion rate after PWHT.The improvement in corrosion resistance is attributed to the increase inΣ3 twin boundaries,which enhance grain boundary stability and reduce susceptibility to localized corrosion.These findings highlight the role of PWHT in refining the microstructure and strengthening corrosion resistance,making HNASS a promising material for demanding applications.
基金Project(20090191120036) supported by the Fund of Doctoral Program of Ministry of Education,China
文摘A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m3/d is conducted combined with a demonstration project. The systematical researches on the efficiency of combined operation conditions of anaerobic-aerobic and anaerobic-aerobic-flocculation as well as chemical phosphorus removal of hypersaline mustard wastewater are conducted. The optimal operation condition and parameters in pretreatment of mustard wastewater in winter （the water temperature ranges 8-15 ~C） are determined： the anaerobic load is 3.0 kg （COD）/（m3.d）, the average COD and phosphate concentration of the inflow are respectively 3 883 mg/L and 35.53 mg/L and the dosage of flocculent （PAC） is 400 mg/L. The anaerobic-aerobic-flocculation combined operation condition and postpositive phosphorous removal with ferrous sulfate are employed. After treatment, the COD of the effluent is 470 mg/L and the average phosphate concentration is 5.09 mg/L. The effluent could achieve the third-level of Integrated Wastewater Discharge Standard （GB 8978--1996）.
文摘To improve the microstructure and properties of the electron beam welded joints, the vacuum or furnace whole post weld heat treatment (FWPWHT) usually should be done on it. The electron beam local post weld heat treatment (EBLPWHT) is a rather new heat treatment procedure that provides the advantages of high precision, flexibility and efficiency, energy saving and higher productivity. In this paper, the microstructure, mechanical properties, fracture toughness and fatigue properties of electron beam welded joints of 30CrMnSiNi2A steel in as-welded (AW) and EBLPWHT conditions have been investigated respectively. The results show that the microstructures of different zones of joints in as-welded condition are changed by EBLPWHT procedure, in which the welds from coarse needle martensite into lath-shaped martensite; the main structures of heat affected zones (HAZ) from lath-shaped martensite into lower bainite. The properties of welded joints can be improved by the EBLPWHT in some extent, especially the fracture toughness of the welds and the fatigue crack resistance of welded joints can be sufficiently improved. However, more appropriate heat treatment parameters of the EBLPWHT have to be studied in order to increase the mechanical properties of base metal near by the HAZ.
基金Project(51305386)supported by the National Natural Science Foundation of ChinaProject(E2013203093)supported by the Natural Science Foundation of Hebei Province,China
文摘The new forming process of AA6061 alloy tube, including solution treatment, granule medium internal high-pressure forming and aging treatment, was developed. The AA6061 alloy tube via heat treatment satisfied the forming requirement, and the granule medium internal high pressure forming method for AA6061 alloy tube was also realized by using convenient implementation with low requirement of equipment and flexible design of product. At a solution temperature of 560℃ and time of 120 min, the elongation of the AA6061 extruded tube increases by 300% and the strength and the hardness dramatically decrease too. Therefore, the AA6061 alloy tube meets the requirement of internal high-pressure forming because of the improvement of formability. The experiments shows that the strength and hardness of AA6061 alloy workpiece recover to that of the as-received alloy at an aging temperature of 180℃ and time of 360 min, and the strength of AA6061 alloy workpiece is equal to the base alloy. The typical parts of convex ring tube, stepped shaft tube and hexagonal tube were successfully produced in lab by using the present forming method. The forming tests show that the maximum expansion ratio(MER) of the AA6061 extruded tube increases by 25.5% and the material properties of formed AA6061 alloy tube reached the performance of as-received alloy.
基金Projects(2009GG10005004, 2010GHY10504) supported by the Scientific and Technological Foundation of Shandong Province,ChinaProject(2011GHY11531) supported by the Science and Technology Development Program of Shandong Province,ChinaProject(ZR2009BM015) supported by the Natural Science Foundation of Shandong Province,China
文摘A coupled system consisting of an upflow membrane-less microbial fuel cell (upflow ML-MFC) and a photobioreactor was developed, and its effectiveness for continuous wastewater treatment and electricity production was evaluated. Wastewater was fed to the upflow ML-MFC to remove chemical oxygen demand (COD), phosphorus and nitrogen with simultaneous electricity generation. The effluent from the cathode compartment of the upflow ML-MFC was then continuously fed to an external photobioreactor for removing the remaining phosphorus and nitrogen using microalgae. Alone, the upflow ML-MFC produces a maximum power density of 481 mW/m 3 , and obtains 77.9% COD, 23.5% total phosphorus (TP) and 97.6% NH4+-N removals. When combined with the photobioreactor, the system achieves 99.3% TP and 99.0% NH4+-N total removal. These results show both the effectiveness and the potential application of the coupled system to continuously treat domestic wastewater and simultaneously generate electricity and biomass.
文摘The effects of postweld heat treatment on the microstructure and metallurgical properties of a bronze–carbon steel(st37)explosively bonded interface were studied.Explosive welding was done under 1.5-and 2-mm standoff distances and different conditions of explosive charge.Samples were postweld heat treated for 4 and 16 h in the furnace at 250°C and 500°C and then air cooled.Laboratory studies using optical microscopy,scanning electron microscopy,and microhardness testing were used to evaluate the welded samples.Microstructural examinations showed that by increasing the standoff distance and the explosive charge,the interface of bronze to steel became wavier.The microhardness test result showed that the hardness of the samples was higher near the joint interface compared with other areas because of the intensive plastic deformation,which was caused by the explosion force.The results show that increasing the heat treatment temperature and time caused the intermetallic compounds’layer thickness to increase,and,because of the higher diffusion of copper and tin,the iron amount in the intermetallic compounds decreased.Also,because of the increase in heat treatment temperature and time,internal stresses were released,and the interface hardness decreased.
基金Project(2017YFB0306001)supported by National Key R&D Program of China。
文摘A new process of AlN removal from secondary aluminum dross(SAD)by pyrometallurgical treatment with added cryolite was applied for solving the problem of recycling the secondary aluminum dross.The response surface methodology(RSM)was used to design experiments and optimize parameters.The results show that adding the appropriate amount of cryolite can effectively promote the oxidation of AlN in the SAD,and too much cryolite will reduce the promotion effect.The effects of roasting temperature and cryolite on the denitrification rate are the most significant(p<0.0001)followed by holding time.Predicted values of the denitrification rate are found to be in good agreement with experimental values(R^(2)=0.9894 and R_(adj)^(2)=0.9775),which confirms the validity of the model employed.The optimum conditions of roasting temperature of 750°C,holding time of 194 min,mass fraction of cryolite of 17.7%are obtained according to the quadratic model.Under these conditions,the maximum actual denitrification rate reaches 94.71%and the AlN content in the SAD is only 0.55 wt%.The unfired brick with compressive strength of 18.62 MPa(GB/T 2542−2012)was prepared based on the roasted SAD.
基金Project(20171BAB206005)supported by the Natural Science Foundation of Jiangxi Province,ChinaProject(20153BCB23023)supported by the Training Program Foundation for Young Scientists of Jiangxi Province,ChinaProject(51961026)supported by the National Natural Science Foundation of China。
文摘The microstructure and Gd-rich phase evolution of as-cast AZ31-xGd(x=0,1.5 wt.%,2.0 wt.%and 2.5 wt.%)magnesium alloys during semi-solid isothermal heat treatment were investigated deeply in the present work.Results showed that the lamellar(Mg,Al)3Gd phases transformed into the particle-like Al2Gd phases in AZ31 magnesium alloys with Gd addition during semi-solid isothermal heat treatment,leading to yielding more sphericalα-Mg grains.When Gd content is 2.0 wt.%,the size of semi-solid spherical grains reaches the minimum.The main mechanism of grain refinement lies in the remelting of dendritic branches as well as the auxiliary effect of a small number of Al2Gd particles as grain refining inoculants.Meanwhile,Al2Gd particles enriched at the solid-liquid interfaces can remarkably retard the growth rate ofα-Mg grains.A reduction of deformation resistance has been successfully achieved in AZ31-2.0Gd magnesium alloy after semi-solid isothermal heat treatment,which shows a moderate compressive deformation resistance(230 MPa),comparing to the as-cast AZ31 magnesium alloy(280 MPa)and semi-solid AZ31 magnesium alloy(209 MPa).
基金Project(2012CB691503)supported by the National Key Basic Research and Development Program of ChinaProject(2016B090931001)supported by Science and Technology Program of Guangdong Province,China
文摘Al-Zn-Mg-Sc-Zr alloy samples were annealed to four different states （under-aging, peak-aging, over-aging and double-aging） and then thoroughly investigated by means of electron backscatter diffraction （EBSD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, tensile and fatigue crack growth rate tests to explore the influence of annealing treatment on microstmcture and fatigue crack growth behavior. The results indicate that Al3（Sc,Zr） particles can effectively refine grains and enhance tensile properties and fatigue properties. After annealing treatment, the under-aged sample and double-aged sample obtained average grain sizes of 4.9473 and 4.1257 μm, and the maximum value of yield/tensile strength （561 MPa/581 MPa） was obtained in peak-aged state. In the Paris region, fatigue crack growth rate, crack deflection and bifurcation, crack blunting and inter/trans-granular propagation were discussed based on data fitting and Laird model and Griffith theory. And the results show that the under-aged sample possesses the best resistance to fatigue crack propagation and the most tortuous and bifurcated crack path. For all samples, the fatigue crack growth rate in the rupture region was inversely proportional to yield strength.
