There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinni...There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinning(MS).The effects of Ti particle content on the microstructure and mechanical properties of AZ91/Ti_(P) ribbon were studied by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),transmission electron microscopy(TEM),three-dimensional profiling(3D-P)and calculation of supercooling rate.The results show that the grain refinement of AZ91 ribbon prepared by rapid solidification is very significant and the grain refinement is further improved with the increase of Ti particle content;at the same time,the growth of β-Mg_(17)Al_(12) is inhibited,and the interface reaction between Ti and Mg leads to the formation of interfaces around Ti particles.These nano-scale Ti_(3)Al and Al_(3)Ti interface compounds uniformly wrap the Ti particles.It is believed that the addition of Ti particles not only helps to refine the surrounding grains,but also increases the dislocations in the MMC ribbon and forms a good interface,thereby improving the mechanical properties.Compared with AZ91 alloy ribbon,the yield strength and tensile strength of MMC material containing 5 wt.%Ti particles increased by 25.0%and 22.7% respectively.The elongation only decreased by 10.9%.AZ91/5 wt.%Ti_(P) ribbon has a better balance between high strength and high elongation.The analysis shows that the strengthening effect of this mechanical property is mainly attributed to fine grain strengthening,dislocation strengthening and non-basal slip.展开更多
The photocatalytic oxidation of methane to methanol using molecule oxygen directly is an attractive catalytic reaction,but designing catalysts to avoid over-oxidation remains a significant challenge.Herein,Cu single-a...The photocatalytic oxidation of methane to methanol using molecule oxygen directly is an attractive catalytic reaction,but designing catalysts to avoid over-oxidation remains a significant challenge.Herein,Cu single-atom anchored on the defective carbon nitride structure(Cu SA/Def-CN)is designed for selective photocatalytic oxidation of methane into methanol using O_(2) under mild conditions.The Cu SA/Def-CN catalyst exhibits a high methanol selectivity of 92.8%under optimized conditions.Mechanistic studies reveal a synergistic effect between Def-CN and Cu SA,where Def-CN is responsible for the in-situ generation of hydrogen peroxide,which is subsequently decomposed by the Cu SA sites to produce·OH radicals that play a key role in the rate-determining step of methane activation to form methanol.Additionally,the presence of Cu SA not only enhances the electron-hole separation efficiency and improves the transfer of the photo-generated charges,but also increases the number of active sites for methane adsorption and activation.These insights provide valuable guidance for designing efficient catalysts for the highly selective photocatalytic oxidation of methane to methanol.展开更多
In oil and gas well cementing processes,accurately predicting the bottom hole circulating temperature(BHCT)is critical to ensuring effective zonal isolation.Overestimating the temperature can lead to excessive retarda...In oil and gas well cementing processes,accurately predicting the bottom hole circulating temperature(BHCT)is critical to ensuring effective zonal isolation.Overestimating the temperature can lead to excessive retardation issues,while underestimation can cause cementing accidents.Current methods for calculating the BHCT of cement slurry typically simplify the cementing processes to a single-fluid circulation and ignore the impact of pre-cementing processes on temperature,leading to significant discrepancies between calculated and actual results.In this study,the wellbore and formation are simplified into a two-dimensional axisymmetric structure,and a mathematical model of the temperature field under multi-fluid and multi-step conditions is established based on the law of energy conservation.The finite volume method was used to discretize the model,and a transient temperature field solver for the entire cementing process was developed,which can numerically calculate the temperature of any fluid at any time,any location.For an actual well example,the temperature distribution of the wellbore and formation after casing running is taken as the initial condition.Numerical calculations were performed sequentially to calculate the temperature fields of circulation flushing,wellbore preparation,and cementing,as well as the BHCT of the cement slurry.The study reveals that during the circulation flushing stage,the maximum temperature point in the wellbore is located at a distance of about 366 m above the bottom of the well.In the wellbore preparation stage,due to static heat exchange,the maximum temperature point gradually shifts to the bottom of the well.The BHCT of cement slurry changes continuously under cementing processes with multi-fluid and multi-step,making it a transient value.The BHCT of the lead slurry and tail slurry are not equal,with the maximum BHCT of the tail slurry being 2.46°C higher than that of the lead slurry.If circulation flushing and wellbore preparation are not considered,the calculated BHCT of the cement slurry will have errors of+6.8%and-1.9%.The study highlighted that considering thermal effects of all cementing stages,such as circulation flushing and wellbore preparation,in BHCT calculations can help improve prediction accuracy.展开更多
In the present study,three types of bimetal composites,Al 6082 sleeve/Al 6082 core,Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core,were fabricated by drilling and assembling.The rule of mixtures(ROM)for th...In the present study,three types of bimetal composites,Al 6082 sleeve/Al 6082 core,Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core,were fabricated by drilling and assembling.The rule of mixtures(ROM)for the flow curves and yield strengths during compressive test were addressed.Our results show that the ROM can predict well the experimental flow curves and yield strengths of bimetal composites without bonding,irrespectively of the different strain hardening behavior between the two components.展开更多
A grain-size gradient Ni Ti ribbon with multiple-step shape transition was papered by means of meltspinning.The ribbons contain coarse and fine grains in the free surface side and copper roller surface side,respective...A grain-size gradient Ni Ti ribbon with multiple-step shape transition was papered by means of meltspinning.The ribbons contain coarse and fine grains in the free surface side and copper roller surface side,respectively.The grain-size gradient microstructure induces a two-stage phase transformation behavior in the ribbons during heating or cooling.After tensile deformation pre-treatment,the ribbons exhibit a back-and-forth shape change(shape A→B→A)upon a single heating or cooling process,resulting from the sequential phase transformation through the thickness of the ribbon as dictated by gradient grain size.The activating performance of the ribbons,i.e.shape transition amplitude and speed,can be customized by controlling the pre-deformation strain.This work offers a new opportunity for innovative designs to reach a novel shape memory behavior in Ni Ti alloys conveniently and efficiently.展开更多
Accumulative roll bonding(ARB)is a severe plastic deformation method to prepare the metallic composite material by physical method at room to elevate temperature,without the generation of additional waste solid or gas...Accumulative roll bonding(ARB)is a severe plastic deformation method to prepare the metallic composite material by physical method at room to elevate temperature,without the generation of additional waste solid or gas.With the physical characteristicsmulti-material and hybrid structure,the mechanical and function properties of the ARB composite material,like Al/steel,Al/Mg,Al/Cu,etc.,shall have the"1+1>2"effect on the mechanical and functional properties,including the remarkable properties that include lightweight,high strength,thermal/electrical conductivity,electromagnetic shielding,and other functions.To deeply investigate the preparation method and microstructural evolution of various metal laminates by ARB,as well as the mechanical and functional properties of the laminate,an overview of the history of ARB technique,the breakthrough of ARB sheet properties,as well as the relative products in industries is provided.Addi-tionally,the future development of ARB technology and the utilization of composite materials in different areas will be discussed.展开更多
Objective:To investigate the effect of BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composite on repairing rat critical-sized cranial defects.Methods:The chitosan nanometer hydroxyapatit...Objective:To investigate the effect of BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composite on repairing rat critical-sized cranial defects.Methods:The chitosan nanometer hydroxyapatite collagen composite was prepared and the microcosmic appearance of the composite was observed by scanning electron microscope.The BMP-7 derived-peptide was introduced into the composite by vacuum adsorption.The released peptide content from the scaffold was detected using high performance liquid chromatography at different set times.Critical-sized cranial defects were created on both sides of the parietal bone in 24 adult Sprague-Dawley rats.The BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composites were implanted on the right side as experimental group and the left side was implanted with chitosan nanometer hydroxyapatite biomimetic collagen composites alone as control group.The rats of both groups were killed in batch respectively after 6 and 12 weeks.Macroscopic observation,three-dimensional reconstruction of computed tomography(CT)and histological observation were performed on these samples.Results:The results of scanning electron microscope showed that the surface of the scaffold was porous.The releasing character of BMP-7 derived-peptide belonged to slow release.The result of animal experiment showed that the BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composite could more effectively promote the repair of cranial bone defects comparing with the chitosan nanometer hydroxyapatite biomimetic collagen composite alone.The difference was statistically significant(p<.05).Conclusions:The BMP-7 derived-peptide chitosan nanometer hydroxyapatite collagen biomimetic composite can effectively promote bone regeneration of bone defects.The composite is a kind of ideal scaffold material for bone tissue engineering.展开更多
Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interact...Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interaction between sulfur-loading cathode and liquid electrolyte.The introduction of functional interlayer within the separator and cathode is an effective strategy to stabilize the electrode/electrolyte interface reaction and improve the utilization rate of active sulfur.Herein,conductive composite nanofabrics(CCN)with multifunctional groups are employed as the interlayer of sulfur-loading cathode,in which the PMIA/PAN supporting fibers offer robust mechanical strength and high thermostable performance,and gelatin/polypyrrole functional fibers ensure high electrical conductivity and strong chemical interaction for LiPSs.As demonstrated by the experimental data and material characterizations,the presence of CCN interlayer not only blocks the shuttle behavior of LiPSs,but also strengthens the interface stability of both Li anode and sulfur-loading cathode.Interestingly,the assembled LSBs with CCN interlayer can maintain stable capacity of 686 mAh/g after 200 cycles at 0.5 A/g.This work will provide new ideas for the elaborate design of functional in terlayers/se para tors for LSBs and lithium metal batteries.展开更多
The effect of the initial(Al+Si)/MnO molar ratio and slag composition on MnO recovery from electroslag by remelting at 1773 K was investigated.High-purity aluminum metal and silicon were employed as the deoxidizers to...The effect of the initial(Al+Si)/MnO molar ratio and slag composition on MnO recovery from electroslag by remelting at 1773 K was investigated.High-purity aluminum metal and silicon were employed as the deoxidizers to effectively promote the recovery of manganese metal(MM).The reduction of MnO in slag,through the interaction between molten MM with a deoxidizer and the Na_(2)O-enriched electroslag melt,was assessed both thermodynamically and kinetically.The sulfur content of high-sulfur rejected electrolytic manganese metal(EMM)scrap decreased to 0.58%with high-temperature pretreatment.The mass ratio between slag and high-sulfur rejected EMM scrap is 2/3.When the Al_(2)O_(3)content in the initial slags decreased and the Na_(2)O content increased,the MnO reduction ratio increased.The residual MnO concentration of the slag reduced with increasing the Al–Si deoxidizer content.When the(Al+Si)/MnO molar ratio reached 0.83,the MnO concentration in the final slag was only 3%.A deoxidizer mainly containing aluminum and a small amount of Si could be added to recover MnO from the slag,resulting in the improvement in the cleanliness of final Mn metal.展开更多
The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3....The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3.5-4.0μm)forms,dominated by brittle columnar Al_(12)Mg_(17) intermetallic compounds(IMCs,0.27-0.35μm thick),which act as preferential crack initiation sites.In contrast,Ni foil implantation induces interfacial restructuring during hot rolling:Constrained deformation fragments the Ni foil into grid-like segments with"olive"-shaped crosssections,embedded into Mg/Al matrices.These fragments(56% areal coverage)coexist with dispersed multiphase IMCs(Mg_(2)Ni,Al_(3)Ni,Mg_(3)AlNi,Al_(12)Mg_(17);10-20 nm grains)at fragment edges,forming a hybrid interface of"willow-leaf"Al_(12)Mg_(17) islands and nanoscale Mg_(2)Ni/Al_(3)Ni layers(15-25 nm).Hall-Petch analysis reveals the multiphase IMC interface exhibits 3.6×higher"kd^(-1/2)"strengthening contribution than single-phase Al_(12)Mg_(17) systems,attributed to grain refinement(20 nm vs.260 nm average grain size).Synergistic effects of mechanical interlocking,adhesion hierarchy(Ni-Al>Ni-Mg>Al-Mg),and nanoscale reinforcement collectively enhance peel strength by 78%without compromising bulk tensile properties.展开更多
Background Birth weight is a critical economic trait in livestock production.However,its genetic architecture remains poorly understood due to historical limitations in sample size and reliance on low-density SNP arra...Background Birth weight is a critical economic trait in livestock production.However,its genetic architecture remains poorly understood due to historical limitations in sample size and reliance on low-density SNP arrays.In this study,we utilized low-coverage whole-genome sequencing(lcWGS)to genotype 3,007 Hu sheep,bypassing the cost and resolution constraints of conventional genotyping arrays while achieving scalable genome-wide variant detection.Results LcWGS with high imputation accuracy(97.8%allelic concordance)enabled genome-wide association studies(GWAS)identifying two novel quantitative trait loci(QTLs)on chromosomes 6 and 9.The chromosome 9 QTL encompassed a regulatory region functionally linked to PLAG1 expression through expression quantitative trait locus(eQTL)mapping.Compared with wild-type homozygotes,heterozygous carriers of the lead SNP(chr9:g.35920172A>G)presented a 9.85%increase in birth weight(3.35 kg vs.3.68 kg;Δ=0.33 kg).Notably,the derived allele of this SNP exhibited low frequencies of<0.1 across most global sheep breeds except Dorper,highlighting its potential for selective breeding applications.Leveraging lcWGS data,haplotype-based fine-mapping prioritized three candidate causal variants.A secondary QTL on chromosome 6 colocalized with the FecB mutation,a well-established locus associated with increased litter size.Intriguingly,individuals carrying one FecB allele showed a 6.18%reduction(0.22 kg)in birth weight,which tentatively indicates potential pleiotropic influences on both growth and reproductive traits.Conclusion This study demonstrates the utility of lcWGS as a cost-effective,high-resolution tool for dissecting complex traits in livestock.Our findings not only advance the understanding of birth weight genetics in sheep but also offer a blueprint for accelerating genetic improvement programs in global livestock production through costeffective,genome-wide approaches.展开更多
In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The...In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.展开更多
Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field.However,in a microwave plasma chemical vapor deposition(MPCVD)system,due to the pres...Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field.However,in a microwave plasma chemical vapor deposition(MPCVD)system,due to the presence of unintentional silicon doping sources such as quartz windows,the behavior of silicon vacancy formation in silicon-doped diamond is complex.In this work,the underlying mechanism of formation of silicon vacancies by unintentional silicon doping in diamond is investigated from the perspective of growing surface kinetics in a two-gas-flow MPCVD system.This system is equipped with a novel susceptor geometry designed to deliver an additional gas flow directly onto the substrate surface.Increasing the concentration of growth doping substances on the substrate surface thereby enhances the efficiency of silicon vacancy formation in diamond.At the same time,by changing the substrate deposition angle the distribution of gas and plasma on the substrate surface is changed,thereby regulating the concentration and distribution of silicon vacancies formed by unintentional silicon doping.Experimental and computational results demonstrate that the difference in silicon vacancies formed by unintentional silicon doping in diamond depends on the substances present on the substrate surface and the distribution of plasma.展开更多
To maintain the safety of an open-type hot-metal car and to reduce wheel-rail wear during transportation, simulation models of the main components of such car were built using Pro/E software and then tested. In partic...To maintain the safety of an open-type hot-metal car and to reduce wheel-rail wear during transportation, simulation models of the main components of such car were built using Pro/E software and then tested. In particular, the Pro/E models were imported into ADAMS/Rail for assembly and then used to construct a complete hot-metal car dynamic model. Locomotive wheel-rail attack angle, wheel-rail lateral force, and wear index were used as evaluation parameters during the simulation to analyze the effects of bogie parameter, rail parameter, and speed of the hot-metal car on wheel-rail wear. An improvement scheme for reducing wheel-rail wear was proposed based on the result of the dynamic simulation, wherein wheel-rail wear and curving performance were analyzed and compared. The simulation provided an important reference for evaluating and improving the dynamic performance of the hot-metal car. The applied effect showed that the improvement scheme is effective.展开更多
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+1 种基金the Guangdong Academy of Science Fund(2020GDASYL-20200101001)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘There are few studies on the preparation of magnesium matrix composites(MMCs)by rapid solidification.This study aims to add minor amounts of Ti particles to AZ91 alloy and prepare AZ91/Ti_(P) MMC ribbon by Melt-Spinning(MS).The effects of Ti particle content on the microstructure and mechanical properties of AZ91/Ti_(P) ribbon were studied by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),X-ray diffraction(XRD),transmission electron microscopy(TEM),three-dimensional profiling(3D-P)and calculation of supercooling rate.The results show that the grain refinement of AZ91 ribbon prepared by rapid solidification is very significant and the grain refinement is further improved with the increase of Ti particle content;at the same time,the growth of β-Mg_(17)Al_(12) is inhibited,and the interface reaction between Ti and Mg leads to the formation of interfaces around Ti particles.These nano-scale Ti_(3)Al and Al_(3)Ti interface compounds uniformly wrap the Ti particles.It is believed that the addition of Ti particles not only helps to refine the surrounding grains,but also increases the dislocations in the MMC ribbon and forms a good interface,thereby improving the mechanical properties.Compared with AZ91 alloy ribbon,the yield strength and tensile strength of MMC material containing 5 wt.%Ti particles increased by 25.0%and 22.7% respectively.The elongation only decreased by 10.9%.AZ91/5 wt.%Ti_(P) ribbon has a better balance between high strength and high elongation.The analysis shows that the strengthening effect of this mechanical property is mainly attributed to fine grain strengthening,dislocation strengthening and non-basal slip.
文摘The photocatalytic oxidation of methane to methanol using molecule oxygen directly is an attractive catalytic reaction,but designing catalysts to avoid over-oxidation remains a significant challenge.Herein,Cu single-atom anchored on the defective carbon nitride structure(Cu SA/Def-CN)is designed for selective photocatalytic oxidation of methane into methanol using O_(2) under mild conditions.The Cu SA/Def-CN catalyst exhibits a high methanol selectivity of 92.8%under optimized conditions.Mechanistic studies reveal a synergistic effect between Def-CN and Cu SA,where Def-CN is responsible for the in-situ generation of hydrogen peroxide,which is subsequently decomposed by the Cu SA sites to produce·OH radicals that play a key role in the rate-determining step of methane activation to form methanol.Additionally,the presence of Cu SA not only enhances the electron-hole separation efficiency and improves the transfer of the photo-generated charges,but also increases the number of active sites for methane adsorption and activation.These insights provide valuable guidance for designing efficient catalysts for the highly selective photocatalytic oxidation of methane to methanol.
基金supported by the National Natural Science Foundation of China(No.U22B6003 and No.52274010)the China Scholarship Council(No.202008080235)。
文摘In oil and gas well cementing processes,accurately predicting the bottom hole circulating temperature(BHCT)is critical to ensuring effective zonal isolation.Overestimating the temperature can lead to excessive retardation issues,while underestimation can cause cementing accidents.Current methods for calculating the BHCT of cement slurry typically simplify the cementing processes to a single-fluid circulation and ignore the impact of pre-cementing processes on temperature,leading to significant discrepancies between calculated and actual results.In this study,the wellbore and formation are simplified into a two-dimensional axisymmetric structure,and a mathematical model of the temperature field under multi-fluid and multi-step conditions is established based on the law of energy conservation.The finite volume method was used to discretize the model,and a transient temperature field solver for the entire cementing process was developed,which can numerically calculate the temperature of any fluid at any time,any location.For an actual well example,the temperature distribution of the wellbore and formation after casing running is taken as the initial condition.Numerical calculations were performed sequentially to calculate the temperature fields of circulation flushing,wellbore preparation,and cementing,as well as the BHCT of the cement slurry.The study reveals that during the circulation flushing stage,the maximum temperature point in the wellbore is located at a distance of about 366 m above the bottom of the well.In the wellbore preparation stage,due to static heat exchange,the maximum temperature point gradually shifts to the bottom of the well.The BHCT of cement slurry changes continuously under cementing processes with multi-fluid and multi-step,making it a transient value.The BHCT of the lead slurry and tail slurry are not equal,with the maximum BHCT of the tail slurry being 2.46°C higher than that of the lead slurry.If circulation flushing and wellbore preparation are not considered,the calculated BHCT of the cement slurry will have errors of+6.8%and-1.9%.The study highlighted that considering thermal effects of all cementing stages,such as circulation flushing and wellbore preparation,in BHCT calculations can help improve prediction accuracy.
基金Guangdong Academy of Science Fund(2020GDASYL-20200101001,2018GDASCX-0967,2019GDASYL-0302017 and 2019GDASYL-0502009)National Natural Science Foundation of China(51905111)+1 种基金Guangdong Science and Technology Project(2018dr005)Guangzhou Science and Technology Project(201704030094).
文摘In the present study,three types of bimetal composites,Al 6082 sleeve/Al 6082 core,Mg AZ31 sleeve/Mg AZ31 core and Al 6082 sleeve/Mg AZ31 core,were fabricated by drilling and assembling.The rule of mixtures(ROM)for the flow curves and yield strengths during compressive test were addressed.Our results show that the ROM can predict well the experimental flow curves and yield strengths of bimetal composites without bonding,irrespectively of the different strain hardening behavior between the two components.
基金supported by National Key R&D Program of China(2018YFB1105100)the NSFC(51971244,51731010,1637207)+2 种基金Science Foundation of China University of Petroleum,Beijing(2462018BJC005)the Pre-research Program of Frontier ScienceMinistry of Education(6141A020222)。
文摘A grain-size gradient Ni Ti ribbon with multiple-step shape transition was papered by means of meltspinning.The ribbons contain coarse and fine grains in the free surface side and copper roller surface side,respectively.The grain-size gradient microstructure induces a two-stage phase transformation behavior in the ribbons during heating or cooling.After tensile deformation pre-treatment,the ribbons exhibit a back-and-forth shape change(shape A→B→A)upon a single heating or cooling process,resulting from the sequential phase transformation through the thickness of the ribbon as dictated by gradient grain size.The activating performance of the ribbons,i.e.shape transition amplitude and speed,can be customized by controlling the pre-deformation strain.This work offers a new opportunity for innovative designs to reach a novel shape memory behavior in Ni Ti alloys conveniently and efficiently.
基金supported by Special Topic of the Industrialization of Scientific and Technological Achievements from Hong Kong and Macao to Guangdong Province(Grant No.2023A0505030002)Shenzhen-Hong Kong-Macao Sciencaend Technology Program(Category C)(Grant No.SGDX20220530111402013)+2 种基金Department of Science and Technology of Guangdong Province(Grant No.2022A0505050081)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030006)the Guangdong Academy of Science Fund(Grant No.2020GDASYL-20200101001).
文摘Accumulative roll bonding(ARB)is a severe plastic deformation method to prepare the metallic composite material by physical method at room to elevate temperature,without the generation of additional waste solid or gas.With the physical characteristicsmulti-material and hybrid structure,the mechanical and function properties of the ARB composite material,like Al/steel,Al/Mg,Al/Cu,etc.,shall have the"1+1>2"effect on the mechanical and functional properties,including the remarkable properties that include lightweight,high strength,thermal/electrical conductivity,electromagnetic shielding,and other functions.To deeply investigate the preparation method and microstructural evolution of various metal laminates by ARB,as well as the mechanical and functional properties of the laminate,an overview of the history of ARB technique,the breakthrough of ARB sheet properties,as well as the relative products in industries is provided.Addi-tionally,the future development of ARB technology and the utilization of composite materials in different areas will be discussed.
文摘Objective:To investigate the effect of BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composite on repairing rat critical-sized cranial defects.Methods:The chitosan nanometer hydroxyapatite collagen composite was prepared and the microcosmic appearance of the composite was observed by scanning electron microscope.The BMP-7 derived-peptide was introduced into the composite by vacuum adsorption.The released peptide content from the scaffold was detected using high performance liquid chromatography at different set times.Critical-sized cranial defects were created on both sides of the parietal bone in 24 adult Sprague-Dawley rats.The BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composites were implanted on the right side as experimental group and the left side was implanted with chitosan nanometer hydroxyapatite biomimetic collagen composites alone as control group.The rats of both groups were killed in batch respectively after 6 and 12 weeks.Macroscopic observation,three-dimensional reconstruction of computed tomography(CT)and histological observation were performed on these samples.Results:The results of scanning electron microscope showed that the surface of the scaffold was porous.The releasing character of BMP-7 derived-peptide belonged to slow release.The result of animal experiment showed that the BMP-7 derived-peptide chitosan nanometer hydroxyapatite biomimetic collagen composite could more effectively promote the repair of cranial bone defects comparing with the chitosan nanometer hydroxyapatite biomimetic collagen composite alone.The difference was statistically significant(p<.05).Conclusions:The BMP-7 derived-peptide chitosan nanometer hydroxyapatite collagen biomimetic composite can effectively promote bone regeneration of bone defects.The composite is a kind of ideal scaffold material for bone tissue engineering.
基金the National Key Research and Development Program of China(No.2018YFC1903400)the Key Program for International S&T Cooperation Projects of China(No.2021YFE0106800)+1 种基金the National Natural Science Foundation of China(Nos.52164020,52174248)the Science and Technology Research Project of Education Department of Jiangxi Province,China(No.GJJ190442).
基金supported by National Natural Science Foundation of China(No.22309029)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110089)+2 种基金Dongguan Social Development Technology Foundation(No.20231800907933)Collaborative Innovation Center of Marine Science and Technology of Hainan University(No.XTCX2022HYC14)Start-up Research Foundation of Hainan University(No.KYQD(ZR)-23069)。
文摘Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interaction between sulfur-loading cathode and liquid electrolyte.The introduction of functional interlayer within the separator and cathode is an effective strategy to stabilize the electrode/electrolyte interface reaction and improve the utilization rate of active sulfur.Herein,conductive composite nanofabrics(CCN)with multifunctional groups are employed as the interlayer of sulfur-loading cathode,in which the PMIA/PAN supporting fibers offer robust mechanical strength and high thermostable performance,and gelatin/polypyrrole functional fibers ensure high electrical conductivity and strong chemical interaction for LiPSs.As demonstrated by the experimental data and material characterizations,the presence of CCN interlayer not only blocks the shuttle behavior of LiPSs,but also strengthens the interface stability of both Li anode and sulfur-loading cathode.Interestingly,the assembled LSBs with CCN interlayer can maintain stable capacity of 686 mAh/g after 200 cycles at 0.5 A/g.This work will provide new ideas for the elaborate design of functional in terlayers/se para tors for LSBs and lithium metal batteries.
基金the financial support from the Anhui Key Laboratory of Low Carbon Metallurgy and Solid Waste Resource Utilization(Anhui University of Technology)(No.SKF23-01)Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology(No.FMRUlab23-1010)+1 种基金Open Project of State Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2022-07)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200).
文摘The effect of the initial(Al+Si)/MnO molar ratio and slag composition on MnO recovery from electroslag by remelting at 1773 K was investigated.High-purity aluminum metal and silicon were employed as the deoxidizers to effectively promote the recovery of manganese metal(MM).The reduction of MnO in slag,through the interaction between molten MM with a deoxidizer and the Na_(2)O-enriched electroslag melt,was assessed both thermodynamically and kinetically.The sulfur content of high-sulfur rejected electrolytic manganese metal(EMM)scrap decreased to 0.58%with high-temperature pretreatment.The mass ratio between slag and high-sulfur rejected EMM scrap is 2/3.When the Al_(2)O_(3)content in the initial slags decreased and the Na_(2)O content increased,the MnO reduction ratio increased.The residual MnO concentration of the slag reduced with increasing the Al–Si deoxidizer content.When the(Al+Si)/MnO molar ratio reached 0.83,the MnO concentration in the final slag was only 3%.A deoxidizer mainly containing aluminum and a small amount of Si could be added to recover MnO from the slag,resulting in the improvement in the cleanliness of final Mn metal.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)Key Project of Chongqing Technology Innovation and Application Development Special Project(CSTB2023TIADKPX0016,CSTB2022TIAD-KPX0027)+1 种基金National Natural Science Foundation of China(51971183)the Science and Technology Program of Xinjiang Production and Construction Corps(2024AB056).
文摘The paper study the interfacial mechanical properties and structural evolution mechanisms in 6061/AZ31B/6061 composite plates with and without Ni foil interlayers.For Ni-free interfaces,a continuous diffusion layer(3.5-4.0μm)forms,dominated by brittle columnar Al_(12)Mg_(17) intermetallic compounds(IMCs,0.27-0.35μm thick),which act as preferential crack initiation sites.In contrast,Ni foil implantation induces interfacial restructuring during hot rolling:Constrained deformation fragments the Ni foil into grid-like segments with"olive"-shaped crosssections,embedded into Mg/Al matrices.These fragments(56% areal coverage)coexist with dispersed multiphase IMCs(Mg_(2)Ni,Al_(3)Ni,Mg_(3)AlNi,Al_(12)Mg_(17);10-20 nm grains)at fragment edges,forming a hybrid interface of"willow-leaf"Al_(12)Mg_(17) islands and nanoscale Mg_(2)Ni/Al_(3)Ni layers(15-25 nm).Hall-Petch analysis reveals the multiphase IMC interface exhibits 3.6×higher"kd^(-1/2)"strengthening contribution than single-phase Al_(12)Mg_(17) systems,attributed to grain refinement(20 nm vs.260 nm average grain size).Synergistic effects of mechanical interlocking,adhesion hierarchy(Ni-Al>Ni-Mg>Al-Mg),and nanoscale reinforcement collectively enhance peel strength by 78%without compromising bulk tensile properties.
基金supported by the Biological Breeding-National Science and Technology Major Project(2022ZD0401403)Shaanxi Provincial Key Research and Development Program(2024NC2-GJHX-15)Shaanxi Livestock and Poultry Breeding Double-chain Fusion Key Project(2022GD-TSLD-46-0401).
文摘Background Birth weight is a critical economic trait in livestock production.However,its genetic architecture remains poorly understood due to historical limitations in sample size and reliance on low-density SNP arrays.In this study,we utilized low-coverage whole-genome sequencing(lcWGS)to genotype 3,007 Hu sheep,bypassing the cost and resolution constraints of conventional genotyping arrays while achieving scalable genome-wide variant detection.Results LcWGS with high imputation accuracy(97.8%allelic concordance)enabled genome-wide association studies(GWAS)identifying two novel quantitative trait loci(QTLs)on chromosomes 6 and 9.The chromosome 9 QTL encompassed a regulatory region functionally linked to PLAG1 expression through expression quantitative trait locus(eQTL)mapping.Compared with wild-type homozygotes,heterozygous carriers of the lead SNP(chr9:g.35920172A>G)presented a 9.85%increase in birth weight(3.35 kg vs.3.68 kg;Δ=0.33 kg).Notably,the derived allele of this SNP exhibited low frequencies of<0.1 across most global sheep breeds except Dorper,highlighting its potential for selective breeding applications.Leveraging lcWGS data,haplotype-based fine-mapping prioritized three candidate causal variants.A secondary QTL on chromosome 6 colocalized with the FecB mutation,a well-established locus associated with increased litter size.Intriguingly,individuals carrying one FecB allele showed a 6.18%reduction(0.22 kg)in birth weight,which tentatively indicates potential pleiotropic influences on both growth and reproductive traits.Conclusion This study demonstrates the utility of lcWGS as a cost-effective,high-resolution tool for dissecting complex traits in livestock.Our findings not only advance the understanding of birth weight genetics in sheep but also offer a blueprint for accelerating genetic improvement programs in global livestock production through costeffective,genome-wide approaches.
基金supported by the National Key Research and Development Program of China(2022YFB3708400)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)+4 种基金the Youth Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202301)the Guangdong Academy of Science Fund(2020GDASYL-20200101001,2023GDASQNRC-0210,2023GDASQNRC-0321)the Guangdong Science and Technology plan project(2023A0505030002)the GINM’Special Project of Science and Technology Development(2023GINMZX-202301020108)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043).
文摘In this study,microstructure and mechanical behavior of Mg/Al composite plates with Ti foil interlayer were systematically studied,with a great emphasis on the effect of different thicknesses of Ti foil interlayer.The results show that compared to 100μm thick Ti foil,10μm thick Ti foil is more prone to fracture and is evenly distributed in fragments at the interface.The introduction of Ti foil can effectively refine the grain size of Mg layers of as-rolled Mg/Al composite plates,10μm thick Ti foil has a better refining effect than 100μm thick Ti foil.Ti foil can effectively increase the yield strength(YS)and ultimate strength(UTS)of as-rolled Mg/Al composite plates,10μm thick Ti foil significantly improves the elongation(El)of Mg/Al composite plate,while 100μm thick Ti foil slightly weakens the El.After annealing at 420℃ for 0.5 h and 4 h,Ti foil can inhibit the formation of intermetallic compounds(IMCs)at the interface of Mg/Al composite plates,which effectively improves the YS,UTS and El of Mg/Al composite plates.In addition,Ti foil can also significantly enhance the interfacial shear strength(SS)of Mg/Al composite plates before and after annealing.
基金supported by the National Natural Science Foundation of China(Grant No.62274084)the Fundamental Research Funds for the Central Universities(Grant No.0210-14380193).
文摘Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field.However,in a microwave plasma chemical vapor deposition(MPCVD)system,due to the presence of unintentional silicon doping sources such as quartz windows,the behavior of silicon vacancy formation in silicon-doped diamond is complex.In this work,the underlying mechanism of formation of silicon vacancies by unintentional silicon doping in diamond is investigated from the perspective of growing surface kinetics in a two-gas-flow MPCVD system.This system is equipped with a novel susceptor geometry designed to deliver an additional gas flow directly onto the substrate surface.Increasing the concentration of growth doping substances on the substrate surface thereby enhances the efficiency of silicon vacancy formation in diamond.At the same time,by changing the substrate deposition angle the distribution of gas and plasma on the substrate surface is changed,thereby regulating the concentration and distribution of silicon vacancies formed by unintentional silicon doping.Experimental and computational results demonstrate that the difference in silicon vacancies formed by unintentional silicon doping in diamond depends on the substances present on the substrate surface and the distribution of plasma.
文摘To maintain the safety of an open-type hot-metal car and to reduce wheel-rail wear during transportation, simulation models of the main components of such car were built using Pro/E software and then tested. In particular, the Pro/E models were imported into ADAMS/Rail for assembly and then used to construct a complete hot-metal car dynamic model. Locomotive wheel-rail attack angle, wheel-rail lateral force, and wear index were used as evaluation parameters during the simulation to analyze the effects of bogie parameter, rail parameter, and speed of the hot-metal car on wheel-rail wear. An improvement scheme for reducing wheel-rail wear was proposed based on the result of the dynamic simulation, wherein wheel-rail wear and curving performance were analyzed and compared. The simulation provided an important reference for evaluating and improving the dynamic performance of the hot-metal car. The applied effect showed that the improvement scheme is effective.
