The electrically assisted(EA)deformation process has received considerable attention in recent years,ac-companied by research on current-induced deformation mechanisms.However,there are still challenges in eliminating...The electrically assisted(EA)deformation process has received considerable attention in recent years,ac-companied by research on current-induced deformation mechanisms.However,there are still challenges in eliminating thermal effects,which have prevented a comprehensive understanding of the underlying current-induced mechanisms.Opting for a single crystal(SC)in research provides advantages in decou-pling the nonthermal effect of electric current at smaller scales and eliminating the complex interactions that exist in polycrystalline materials.Therefore,the innovation of this work lies in decoupling the non-thermal effect of electric current and conducting a comprehensive analysis of anisotropic deformation and mechanisms within a Ni-based SC with different crystallographic axes and various current directions dur-ing electrically assisted tensile simulation.A significant tension axis direction in the SC during EA tension was induced by the combination of a higher current direction factor(|cosθ|)and a dimensionless factor for the current density(|J^(α)/J_(0)^(α)|)along the[100]axis.The stress drop within the SC due to the nonthermal effect of electric current generally increased with increasing current direction.This was attributed to the increased dislocation density differences and decreased temperature.The increased stress anisotropy of the SC at a current direction of 45°was attributed to fewer activated(111)slip systems and the pinning effect of more dislocations within these systems.This study advances our understanding of the thermal and nonthermal effects of electric current and offers valuable insights for the informed application of EA deformations in industrial and aerospace settings with SC superalloys.展开更多
Recent research has indicated that sialic acid,such as free sialic acid(N-acetylneuraminic acid,Neu5Ac)and bound sialic acid(3ʹ-sialyllactose,3ʹ-SL),can ameliorate disorders associated with glycolipid metabolism,altho...Recent research has indicated that sialic acid,such as free sialic acid(N-acetylneuraminic acid,Neu5Ac)and bound sialic acid(3ʹ-sialyllactose,3ʹ-SL),can ameliorate disorders associated with glycolipid metabolism,although the underlying mechanisms have yet to be determined.We examined the effects of 3ʹ-SL on glycolipid metabolism in mice fed a high-fat diet.Male C57BL/6J mice were divided into 6 groups:2 model control groups(normal and high-fat diets)and 4 intervention groups(Neu5Ac,and low,moderate,and high-dose 3ʹ-SL).After 8 weeks of continuous gavage intervention,mice in the 3ʹ-SL intervention groups had lower body weight and total fat content;reduced fasting blood glucose,triglycerides,low-density lipoproteins and oxidized-low-density lipoproteins;and increased high-density lipoproteins,but no dosage-dependent of 3ʹ-SL intervention was found,moderate-dose 3ʹ-SL intervention as optimal for further exploration.3ʹ-SL intervention could increase respiratory exchange ratio,energy expenditure,and amount of exercise performed.3ʹ-SL increased the colonic abundances of Akkermansia,Lactobacillus,and Bacteroides,and reduced those of Erysipelatoclostridium,Faecalibaculum,and Aldercreutzia.Changes were also observed in colonic metabolites,and liver gene transcript and metabolites,which were mainly enriched in bile secretion,taurine and hypotaurine metabolism,and insulin resistance.Additionally,3ʹ-SL was observed to regulate genes associated with physiological rhythms,including Clock,Per2,Cry1,and Bhihe41.Collectively,our findings indicate that 3ʹ-SL can contribute to the prevention and control of disorders associated with glucose and lipid metabolism caused by high-fat diets.Compared with Neu5Ac,3ʹ-SL intervention can more effectively ameliorate intestinal flora disorders,enhance bile acid circulation,increase tissue energy expenditure,and reduce lipid synthesis,thereby promoting lipid-lowering effects mediated via the gut-liver axis,and can also enhance energy metabolism and alleviate disorders of glucolipid metabolism by altering physiological rhythms in high fat-diet mice.展开更多
Aiming at the problem of increasing the peak-to-valley difference of grid load and the rising cost of user charging caused by the disorderly charging of large-scale electric vehicles,this paper proposes a coordinated ...Aiming at the problem of increasing the peak-to-valley difference of grid load and the rising cost of user charging caused by the disorderly charging of large-scale electric vehicles,this paper proposes a coordinated charging scheduling strategy for multiple types of electric vehicles based on the degree of urgency of vehicle use.First,considering the range loss characteristics,dynamic time-sharing tariff mechanism,and user incentive policy in the lowtemperature environment of northern winter,a differentiated charging model is constructed for four types of vehicles:family cars,official cars,buses,and cabs.Then,we innovatively introduce the urgency parameter of charging demand for multiple types of vehicles and dynamically divide the emergency and non-emergency charging modes according to the difference between the regular charging capacity and the user’s minimum power demand.When the conventional charging capacity is less than the minimum power demand of the vehicle within the specified time,it is the emergency vehicle demand,and this type of vehicle is immediately charged in fast charging mode after connecting to the grid.On the contrary,it is a non-emergency demand,and the vehicle is connected to the grid to choose the appropriate time to charge in conventional charging mode.Finally,by optimizing the objective function to minimize the peakto-valley difference between the grid and the vehicle owner’s charging cost,and designing the charging continuity constraints to avoid battery damage,it ensures that the vehicle is efficiently dispatched under the premise of meeting the minimum power demand.Simulation results show that the proposed charging strategy can reduce the charging cost of vehicle owners by 26.33%,reduce the peak-to-valley difference rate of the grid by 29.8%,and significantly alleviate the congestion problem during peak load hours,compared with the disordered charging mode,while ensuring that the electric vehicles are not overcharged and meet the electricity demand of vehicle owners.This paper solves the problems of the existing research on the singularity of vehicle models and the lack of environmental adaptability and provides both economic and practical solutions for the cooperative optimization of electric vehicles and power grids in multiple scenarios.展开更多
The scintillating photonic glass has the great potential for medicine imaging,nuclear physics,highenergy physics,and national defense.However,the development of the candidate with the high density remains a significan...The scintillating photonic glass has the great potential for medicine imaging,nuclear physics,highenergy physics,and national defense.However,the development of the candidate with the high density remains a significant challenge.Herein,the superdense scintillating glasses derived from the Ce^(3+)-activated Lu_(2)O_(3)-SiO_(2)binary system were successfully fabricated by the strategy of contactless aerodynamic levitation heating under the N_(2)atmosphere.These glasses are colorless,optical homogeneous,and exhibit superdense density from 6.59 to 7.15 g/cm^(3),representing the highest density among the fast decay glass systems.The materials present excellent radiation-blocking ability,suitable emission wavelength,and fast response,indicating the promise for fast-eve nt X-ray detection.The micro radiation probe was fabricated by connecting the scintillating glass and the optical fiber.The practical application in remote radiation detection is demonstrated and it exhibits excellent linear response and high signalto-noise ratio.The results confirm that the fabricated superdense scintillating glass is promising for application in the field of high-energy radiation detection.展开更多
Collision-induced re-laxation process of CH(X^(2)Π,v=0)radical in various bath gases He,Ar,and N_(2)has been investigated ex-perimentally under low-temperature(26-52 K)supersonic flow conditions.The CH radicals were ...Collision-induced re-laxation process of CH(X^(2)Π,v=0)radical in various bath gases He,Ar,and N_(2)has been investigated ex-perimentally under low-temperature(26-52 K)supersonic flow conditions.The CH radicals were generat-ed with internal excitation by multiphoton photolysis of CHBr_(3)at 248 nm,and its rotational temperature was found to relax to the flow temperature in a few microseconds by colliding with bath gas.The relaxation rate coefficients for CH(X^(2)Π,v=0)radical in He,Ar,and N_(2)flow were obtained by time-resolved laser-induced fluorescence measurements,ranging from 10^(-12)cm^(3)·molecule^(-1)·s^(-1)to 10^(-11)cm^(3)·molecule^(-1)·s^(-1).The N_(2)flow exhibits the highest relax-ation rate for CH(X^(2)Π)radical due to its additional rovibrational levels,which allow for more efficient energy dissipation during collisions compared to monoatomic gases.The Ar flow shows a larger relaxation rate than He flow due to its greater polarizability and stronger long-range interaction with the CH(X^(2)Π)radical.展开更多
The mechanism by which electromagnetic forming(EMF)enhances the formability of metals is unclear owing to the coupling effect of multi-physics fields.In the present work,the associated formability improvement mechanis...The mechanism by which electromagnetic forming(EMF)enhances the formability of metals is unclear owing to the coupling effect of multi-physics fields.In the present work,the associated formability improvement mechanisms were qualitatively categorized and illustrated.This was realized by comparing the formability of fully annealed 2219 aluminum alloy(AA 2219-O)sheet under quasi-static(QS),electromagnetic dynamic(EM),and mechanical dynamic(MD)tensile loadings.It was found that the forming limit of AA 2219-O sheet under EM tensile loading was significantly(45.4%)higher than that under QS tensile loading,and was marginally(3.7%–4.3%)higher than that under MD tensile loading.In addition,the forming limit of AA 2219-O sheet demonstrated a negative dependency on the strain rate within the range of the dynamic tensile tests conducted.The deformation conditions common to EM and MD tensile loadings were responsible for the significant formability improvement compared with QS tensile loading.In particular,the inertial effect was dominant.The different deformation conditions that distinguish EM tensile loading from MD tensile loading resulted in the marginal improvement in formability.This was caused by the absence of a sustaining contact force at the later deformation stage and the lower strain rate.The body force exerted little influence on the formability improvement,and the thermal effect under the two dynamic tensile loadings was negligible.展开更多
High light induced photooxidation （HLIP） usually leads to leaf premature senescence and causes great yield loss in winter wheat. In order to explore the genetic control of wheat tolerance to HLIP stress, a quantitat...High light induced photooxidation （HLIP） usually leads to leaf premature senescence and causes great yield loss in winter wheat. In order to explore the genetic control of wheat tolerance to HLIP stress, a quantitative trait loci （QTL） analysis was conducted on a set of doubled haploid population, derived from two winter wheat cultivars. Actual values of chlorophyll content （Chl）, minimum fluorescence level （Fo）, maximum fluorescence level （Fm）, and the maximum quan^m efficiency of photosystem II （Fv/Fm） under both HLIP and non-stress conditions as well as the ratios of HLIP to non-stress were evaluated. HLIP considerably reduced Chl, Fm, and Fv/Fm, but in- creased Fo, compared with that under non-stress condition. A total of 27, 16, and 28 QTLs were associated with the investigated traits under HLIP and non-stress and the ratios of HLIP to non-stress, respectively. Most of the QTLs for the ratios of HLIP to non-stress collocated or nearly linked with those detected under HLIP condition. HLIP-induced QTLs were mapped on 15 chromosomes, involving in 1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4D, 5B, 6A, 6B, 7A, and 7D while those expressed under non-stress condition involved in nine chromosomes, includ- ing 1B, 1D, 2A, 2B, 3B, 4A, 5A, 5B, and 7A. The expression patterns of QTLs under HLIP condition were different from that under non-stress condition except for six loci on five chromosomes. The phenotypic variance explained by individual QTL ranged from 5.0% to 19.7% under HLIP, 8.3% to 20.8% under non-stress, and 4.9% to 20.2% for the ratios of HLIP to non-stress, respectively. Some markers, for example, Xgwm192 and WMC331 on 4D regulating Chl, Fo, Fm, and Fv/Fm under HLIP condition, might be used in marker assistant selection.展开更多
The microstructural evolution of a Ni-based superalloy under interrupted hot compressive deformation with different cooling rates in the inter-pass stage is investigated. It is found that metadynamic recrystallization...The microstructural evolution of a Ni-based superalloy under interrupted hot compressive deformation with different cooling rates in the inter-pass stage is investigated. It is found that metadynamic recrystallization(MDRX) in the inter-pass stage is more sensitive to the accumulated strain than the deformation temperature which is above the recrystallization temperature. The variations of both the grain distribution and the texture intensity caused by MDRX during the interpass stage result in variations of the yield stress(YS) and the work hardening(WH) rate in each stage. Results also show that the MDRX process in the inter-pass stage has a considerable influence on the final microstructure of three-pass compression. The final grain distribution is more uniform,and the compression texture gradually transforms into recrystallization texture with an increasing degree of MDRX. In order to predict the MDRX fraction in the inter-pass cooling stage, a modified kinetic equation is established, which can reasonably predict the MDRX behavior under multi-pass compression with different conditions in the inter-pass stage. Meanwhile, the influence of the interpass cooling stage on the mechanism of dynamic recrystallization(DRX) is studied. It is universally acknowledged that the discontinuous dynamic recrystallization(DDRX) process is the major deformation mechanism for the Ni-based superalloy. However, the continuous dynamic recrystallization(CDRX) process is promoted in the compression stage with a decrease of the cooling rate in each inter-pass stage.展开更多
Xiaoyan 60(XY60) is a new wheat variety bred in the laboratory of Zhensheng Li.After salt treatment, seedlings of XY60 maintain green leaves and produce longer roots than the high yielding cultivar Zhongmai 175(ZM175)...Xiaoyan 60(XY60) is a new wheat variety bred in the laboratory of Zhensheng Li.After salt treatment, seedlings of XY60 maintain green leaves and produce longer roots than the high yielding cultivar Zhongmai 175(ZM175).To explain these different phenotypes we carried out an RNA-Seq analysis using 12 samples from three tissues of both varieties subjected to salt and control treatments.By comparing data from the salt treated plants with the control, 703, 979, and 1197 differentially expressed genes(DEGs) were detected in new leaves, old leaves, and roots of XY60, respectively.The corresponding numbers for ZM175 were 613, 1401, and 1301.The most significantly enriched Gene Ontology(GO) terms and KEGG pathways were associated with polyunsaturated fatty acid(PUFA) metabolism in both new and old leaves from XY60.They were associated with photosynthesis and energy metabolism in ZM175.The most significantly enriched KEGG pathway in roots of both varieties was “glucosinolate biosynthesis”.In addition, jasmonic acid(JA) concentration in XY60 was higher than in ZM175, although it increased significantly in both varieties following salt treatment.Trends in relative expression levels of AOS, MYC2, and JAZ revealed by qRT-PCR were concordant with those from RNA-Seq.Our results suggest that PUFAs may contribute to salt tolerance in common wheat by enhancing the photosynthetic system and JA-related pathways.展开更多
Differentially expressed genes are thought to regulate the development and progression of oral squamous cell carcinomas （OSCC）. The purpose of this study was to screen differentially expressed mRNAs in OSCC and matc...Differentially expressed genes are thought to regulate the development and progression of oral squamous cell carcinomas （OSCC）. The purpose of this study was to screen differentially expressed mRNAs in OSCC and matched paraneoplastic normal tissues, and to explore the intrinsic mechanism of OSCC development and progres- sion. We obtained the differentially expressed mRNA expression profiles in 10 pairs of fresh-frozen OSCC tissue specimens and matched paraneoplastic normal tissue specimens by high-throughput RNA sequencing. By using Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analyses, the functional significance of the differentially expressed genes were analyzed. We identified 1,120 sig- nificantly up-regulated mRNAs and 178 significantly down-regulated mRNAs in OSCC, compared to normal tissue. The differentially expressed mRNAs were involved in 20 biological processes and 68 signal pathways. Compared to adjacent normal tissue, the expression of MAGEAll was up-regulated; TCHH was down-regulated. These find- ings were verified by real-time PCR. These differentially expressed mRNAs may function as oncogenes or tumor suppressors in the development and progression of OSCC. This study provides novel insights into OSCC. However, further work is needed to determine if these differentially expressed mRNAs have potential roles as diagnostic bio- markers and candidate therapeutic targets for OSCC.展开更多
High-performance batteries with high density and low cost are needed for the development of largescale energy storage fields such as electric vehicles and renewable energy systems.The anode with threedimensional(3D)na...High-performance batteries with high density and low cost are needed for the development of largescale energy storage fields such as electric vehicles and renewable energy systems.The anode with threedimensional(3D)nanoarchitecture is one of the most attractive candidates for high-performance lithiumion batteries(LIBs)and sodium-ion batteries(SIBs)due to its efficient electron/ion transport and high active material mass loading.Although some important breakthroughs have been made in 3D nanoarchitecture anode materials,more improvements are still needed for high cycling stability and high energy density.Herein,the latest research progress of 3D nanoarchitecture anode materials for LIBs and SIBs is reviewed,including nanoporous metal,nanoporous graphene,and their derived foams.Specifically,the storage properties of Li/Na ions,the kinetics of ion/electron transport,and specific chemical interactions are discussed based on the structure design.In addition,the research strategies and structural characteristics of 3D nanoarchitecture anode materials are summarized,providing a reference for the further development of LIBs and SIBs.Meanwhile,the future research directions of LIBs and SIBs have also prospected.展开更多
Background: Sialic acids are a family of ninecarbon sugar compounds with carboxylic acyl derivatives. It exists in bacteria, fish, mammals and other living organisms, participates in and regulates many important life ...Background: Sialic acids are a family of ninecarbon sugar compounds with carboxylic acyl derivatives. It exists in bacteria, fish, mammals and other living organisms, participates in and regulates many important life events, such as cell recognition, membrane flow, endocytosis and so on. Sialic acid is usually located in the outermost layer of the sugar part of the cell membrane and the key positions of secreted glycoconjugates (glycolipids, glycoprotein and lipopolysaccharide). Sialic acid (Sia) is an important material foundation for variety of the structure and founction of glycoconjugates. Sia has been known as nearly 50 members, including N-acetylneuraminic acid (Neu5Ac), N-glycoulylneuraminic acid (Neu5Gc) and deaminoneuraminic acid (KDN) as its core monomer. The rest of the sialic acids are derived from these three monomers. The contents of Sia in Chinese food products are unknown. Objective: To determine the contents of Sia in raw and cooked red meat, seafood, poultry and so on. Design: The following food products were purchased from a Chinese supermarket: pork, beef, lamb, salmon, cod, tuna, cow milk, cheese, butter, duck, chicken and chicken eggs. Human milk was collected from Xiamen Maternity and Child Health Care Hospital (Xiamen, China). All tissues were homogenized and hydrolyzed with 0.05 M, 0.1 M and 0.2 M TFA for 150 min at 80°C in dark, respectively. The concentrations of Neu5Ac, Neu5Gc and KDN were determined by using HPLC with fluorescence detector. Results: The contents of total Sia (μg/g tissue or μg/mL liquid sample) in Chinese raw meat were highest in lamb (269.60), followed by pork (254.88), duck (200.63), chicken (162.86) and beef (88.03). The percentages of Neu5Gc were 36.08%, 26.48%, 0%, 0% and 28.40%, respectively. Cod contained higher levels of Sia (171.63) than salmon (104.43) and tuna (77.98). Only Neu5Ac was 50 found in detected aquatic product. Egg yolk contained the highest level of Sia (682.04), and a higher level of Sia (390.67) was found in the egg white. Also our result showed that human milk contained extremely high level of Sia (602.55). Neu5Ac was the predominant form of Sia in all the deteced samples. KDN was found in cow milk only among the samples, the content was 1.14 μg/g. Conclusion: The highest content of Sia in examined Chinese foods was found in 56 eggs, followed by lamb, pork, duck, cod, chicken, salmon, beef and tuna. Knowledge of the Sia content in conventional foods may help us to better understand possible medical disorders involving the uptake of the “non-human” Neu5Gc from our diet.展开更多
Ug99, also designated as TFKSK, is a race of Puccinia graminis Pers.：Pers f. sp. tn＇tici Eriks. and E. Henn （Pgt） with broad virulence to wheat. It is the first known Pgt race possessing virulence to Sr31, a stem ...Ug99, also designated as TFKSK, is a race of Puccinia graminis Pers.：Pers f. sp. tn＇tici Eriks. and E. Henn （Pgt） with broad virulence to wheat. It is the first known Pgt race possessing virulence to Sr31, a stem rust resistance （Sr） gene deployed in wheat varieties world- wide （Singh et al., 2011 ）. Since the first detection of TFKSK in 1998, a total of 13 Ug99 variants have been identified in several African countries.展开更多
A novel soft robotic arm(SRA)composed of two soft extensible arms(SEAs)and a soft bendable joint(SBJ)for space capture systems is presented in this paper.A diamond origami pattern was applied in the design of the SEAs...A novel soft robotic arm(SRA)composed of two soft extensible arms(SEAs)and a soft bendable joint(SBJ)for space capture systems is presented in this paper.A diamond origami pattern was applied in the design of the SEAs,and large deformations of the SEAs in positive pressure were simulated using the nonlinear finite element method.A kinematic model of the SRA using the Denavit–Hartenberg method based on the assumption of constant curvatures was proposed.A closed-loop model-free control system based on a PID controller was developed using real-time data from a vision sensor system.The kinematic model and closed-loop model-free control system are experimentally evaluated on an SRA prototype by four experiments.The experimental results demonstrate that the derived kinematic model can finely describe the movement of the SRA and that the closed-loop control system can control the SRA to reach the desired destination or trajectory within an acceptable error and performs well in long-term repeated operations.展开更多
The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles （soluble only in liquid） could pin at grain and subgrain boundary to mak...The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles （soluble only in liquid） could pin at grain and subgrain boundary to make the alloy difficultly recrystallise. In this work, a novel multistep reheating regime is developed for recrystallisation and partial melting （RAP） route to prepare fine spheroidal microstructure of semi-solid AI-Zn- Mg-Cu alloy. After reheating to 665 ℃, holding for 4 min and subsequent isothermally holding at 620 ℃ with total heating time of 15 min, fine spheroidal microstructures with grain size of-40 μm were prepared without remained unrecrystallised grains and directionality, which are much finer than the conventionally obtained microstructures （-100 μm）.展开更多
Stem rust, caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn. (Pgt), is a destructive wheat disease and has the potential to cause significant yield losses (Olivera et al., 2015;Soko et al., ...Stem rust, caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn. (Pgt), is a destructive wheat disease and has the potential to cause significant yield losses (Olivera et al., 2015;Soko et al., 2018). The emergence of Pgt race TTKSK, virulent to the widely deployed stem rust resistance gene Sr31 and originally named as isolate Pgt-Ug99 (Pretorius et al., 2000).展开更多
Mechanical properties of TC17 titanium alloy undergo a significant reduction after linear friction welding(LFW),of which the strength and ductility are hard to be improved simultaneously by traditional aging heat trea...Mechanical properties of TC17 titanium alloy undergo a significant reduction after linear friction welding(LFW),of which the strength and ductility are hard to be improved simultaneously by traditional aging heat treatment(AHT),seriously limiting the application of LFW in the manufacturing of TC17 titanium alloy blisks.To this end,the present work proposes to use electric pulse treatment(EPT)to enhance the strength and ductility of TC17 LFW joints simultaneously by improving its microstructure.The results show that,in comparison to the uneven distribution ofαphases in the welding zone(WZ),heat-affected zone(HAZ),and base metal(BM)zone after AHT,EPT can selectively homogenize theαphase distribution of WZ and HAZ without impacting the BM.The selective effect of EPT is reflected as the synergistic influence of the local Joule heating effect and the electron wind effect,which promotes the diffusion ofβphase stabilizing element Mo and leads to a competitive precipitation ofβphase andαphase in theαphase transition temperature range.The ratio ofαphase toβphase in the WZ and HAZ finally approaches an equilibrium point which is similar to that of BM,leading to a uniform distribution ofαphase and realizing the synergy of strength-ductility of LFW joint:the maximum strength increase observed is 12.9%,accompanied by a corresponding elongation increase of 122%(by AHT&EPT),and the maximum plasticity improvement is 185%,accompanied by a corresponding strength increase of 4.3%(by EPT for 1 h).This study provides essential insights for improving the strength and ductility of LFW TC17 titanium alloy blisks and enhancing the applications of LFW in aeroengine components.展开更多
This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of...This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.展开更多
基金National Science Fund for Distinguished Young Scholars(No.52225505)the National Sci-ence and Technology Major Project(No.J2019-VII-0014-0154)+1 种基金the National Natural Science Foundation of China(No.52005412)the Tianjin Natural Science Foundation of China-Multi-input key projects(No.22JCZDJC00650)for financial supports given to this research.
文摘The electrically assisted(EA)deformation process has received considerable attention in recent years,ac-companied by research on current-induced deformation mechanisms.However,there are still challenges in eliminating thermal effects,which have prevented a comprehensive understanding of the underlying current-induced mechanisms.Opting for a single crystal(SC)in research provides advantages in decou-pling the nonthermal effect of electric current at smaller scales and eliminating the complex interactions that exist in polycrystalline materials.Therefore,the innovation of this work lies in decoupling the non-thermal effect of electric current and conducting a comprehensive analysis of anisotropic deformation and mechanisms within a Ni-based SC with different crystallographic axes and various current directions dur-ing electrically assisted tensile simulation.A significant tension axis direction in the SC during EA tension was induced by the combination of a higher current direction factor(|cosθ|)and a dimensionless factor for the current density(|J^(α)/J_(0)^(α)|)along the[100]axis.The stress drop within the SC due to the nonthermal effect of electric current generally increased with increasing current direction.This was attributed to the increased dislocation density differences and decreased temperature.The increased stress anisotropy of the SC at a current direction of 45°was attributed to fewer activated(111)slip systems and the pinning effect of more dislocations within these systems.This study advances our understanding of the thermal and nonthermal effects of electric current and offers valuable insights for the informed application of EA deformations in industrial and aerospace settings with SC superalloys.
基金supported by the Incubation Fund of Zhongshan Hospital,Fudan University(Xiamen Branch)(2020ZSXMYS24).
文摘Recent research has indicated that sialic acid,such as free sialic acid(N-acetylneuraminic acid,Neu5Ac)and bound sialic acid(3ʹ-sialyllactose,3ʹ-SL),can ameliorate disorders associated with glycolipid metabolism,although the underlying mechanisms have yet to be determined.We examined the effects of 3ʹ-SL on glycolipid metabolism in mice fed a high-fat diet.Male C57BL/6J mice were divided into 6 groups:2 model control groups(normal and high-fat diets)and 4 intervention groups(Neu5Ac,and low,moderate,and high-dose 3ʹ-SL).After 8 weeks of continuous gavage intervention,mice in the 3ʹ-SL intervention groups had lower body weight and total fat content;reduced fasting blood glucose,triglycerides,low-density lipoproteins and oxidized-low-density lipoproteins;and increased high-density lipoproteins,but no dosage-dependent of 3ʹ-SL intervention was found,moderate-dose 3ʹ-SL intervention as optimal for further exploration.3ʹ-SL intervention could increase respiratory exchange ratio,energy expenditure,and amount of exercise performed.3ʹ-SL increased the colonic abundances of Akkermansia,Lactobacillus,and Bacteroides,and reduced those of Erysipelatoclostridium,Faecalibaculum,and Aldercreutzia.Changes were also observed in colonic metabolites,and liver gene transcript and metabolites,which were mainly enriched in bile secretion,taurine and hypotaurine metabolism,and insulin resistance.Additionally,3ʹ-SL was observed to regulate genes associated with physiological rhythms,including Clock,Per2,Cry1,and Bhihe41.Collectively,our findings indicate that 3ʹ-SL can contribute to the prevention and control of disorders associated with glucose and lipid metabolism caused by high-fat diets.Compared with Neu5Ac,3ʹ-SL intervention can more effectively ameliorate intestinal flora disorders,enhance bile acid circulation,increase tissue energy expenditure,and reduce lipid synthesis,thereby promoting lipid-lowering effects mediated via the gut-liver axis,and can also enhance energy metabolism and alleviate disorders of glucolipid metabolism by altering physiological rhythms in high fat-diet mice.
基金funded by Science and Technology Project of SGCC(SGJLCC00KJJS2203595).
文摘Aiming at the problem of increasing the peak-to-valley difference of grid load and the rising cost of user charging caused by the disorderly charging of large-scale electric vehicles,this paper proposes a coordinated charging scheduling strategy for multiple types of electric vehicles based on the degree of urgency of vehicle use.First,considering the range loss characteristics,dynamic time-sharing tariff mechanism,and user incentive policy in the lowtemperature environment of northern winter,a differentiated charging model is constructed for four types of vehicles:family cars,official cars,buses,and cabs.Then,we innovatively introduce the urgency parameter of charging demand for multiple types of vehicles and dynamically divide the emergency and non-emergency charging modes according to the difference between the regular charging capacity and the user’s minimum power demand.When the conventional charging capacity is less than the minimum power demand of the vehicle within the specified time,it is the emergency vehicle demand,and this type of vehicle is immediately charged in fast charging mode after connecting to the grid.On the contrary,it is a non-emergency demand,and the vehicle is connected to the grid to choose the appropriate time to charge in conventional charging mode.Finally,by optimizing the objective function to minimize the peakto-valley difference between the grid and the vehicle owner’s charging cost,and designing the charging continuity constraints to avoid battery damage,it ensures that the vehicle is efficiently dispatched under the premise of meeting the minimum power demand.Simulation results show that the proposed charging strategy can reduce the charging cost of vehicle owners by 26.33%,reduce the peak-to-valley difference rate of the grid by 29.8%,and significantly alleviate the congestion problem during peak load hours,compared with the disordered charging mode,while ensuring that the electric vehicles are not overcharged and meet the electricity demand of vehicle owners.This paper solves the problems of the existing research on the singularity of vehicle models and the lack of environmental adaptability and provides both economic and practical solutions for the cooperative optimization of electric vehicles and power grids in multiple scenarios.
基金supported by the National Science Fund for Distinguished Young Scholars(62125502)the National Natural Science Foundation of China(52302002,62305115)Guangdong Basic and Applied Basic Research Foundation(2024A1515011827)。
文摘The scintillating photonic glass has the great potential for medicine imaging,nuclear physics,highenergy physics,and national defense.However,the development of the candidate with the high density remains a significant challenge.Herein,the superdense scintillating glasses derived from the Ce^(3+)-activated Lu_(2)O_(3)-SiO_(2)binary system were successfully fabricated by the strategy of contactless aerodynamic levitation heating under the N_(2)atmosphere.These glasses are colorless,optical homogeneous,and exhibit superdense density from 6.59 to 7.15 g/cm^(3),representing the highest density among the fast decay glass systems.The materials present excellent radiation-blocking ability,suitable emission wavelength,and fast response,indicating the promise for fast-eve nt X-ray detection.The micro radiation probe was fabricated by connecting the scintillating glass and the optical fiber.The practical application in remote radiation detection is demonstrated and it exhibits excellent linear response and high signalto-noise ratio.The results confirm that the fabricated superdense scintillating glass is promising for application in the field of high-energy radiation detection.
基金supported by the National Natural Science Foundation of China(No.22273103)the National Natural Science Foundation of China(NSFC Center for Chemical Dynamics)(No.22288201)+1 种基金Dalian Institute of Chemical Physics(DICP I202230)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(grant GJJSTD20220001)。
文摘Collision-induced re-laxation process of CH(X^(2)Π,v=0)radical in various bath gases He,Ar,and N_(2)has been investigated ex-perimentally under low-temperature(26-52 K)supersonic flow conditions.The CH radicals were generat-ed with internal excitation by multiphoton photolysis of CHBr_(3)at 248 nm,and its rotational temperature was found to relax to the flow temperature in a few microseconds by colliding with bath gas.The relaxation rate coefficients for CH(X^(2)Π,v=0)radical in He,Ar,and N_(2)flow were obtained by time-resolved laser-induced fluorescence measurements,ranging from 10^(-12)cm^(3)·molecule^(-1)·s^(-1)to 10^(-11)cm^(3)·molecule^(-1)·s^(-1).The N_(2)flow exhibits the highest relax-ation rate for CH(X^(2)Π)radical due to its additional rovibrational levels,which allow for more efficient energy dissipation during collisions compared to monoatomic gases.The Ar flow shows a larger relaxation rate than He flow due to its greater polarizability and stronger long-range interaction with the CH(X^(2)Π)radical.
基金financially supported by the National Natural Science Foundation of China(Nos.51575206 and 51705169)the Innovation Funds for Aerospace Science and Technology from China Aerospace Science and Technology Corporation(No.CASC150704)+1 种基金the Science Fund of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body(No.31615006)the Fundamental Research Funds for the Central University(No.2016YXZD055)。
文摘The mechanism by which electromagnetic forming(EMF)enhances the formability of metals is unclear owing to the coupling effect of multi-physics fields.In the present work,the associated formability improvement mechanisms were qualitatively categorized and illustrated.This was realized by comparing the formability of fully annealed 2219 aluminum alloy(AA 2219-O)sheet under quasi-static(QS),electromagnetic dynamic(EM),and mechanical dynamic(MD)tensile loadings.It was found that the forming limit of AA 2219-O sheet under EM tensile loading was significantly(45.4%)higher than that under QS tensile loading,and was marginally(3.7%–4.3%)higher than that under MD tensile loading.In addition,the forming limit of AA 2219-O sheet demonstrated a negative dependency on the strain rate within the range of the dynamic tensile tests conducted.The deformation conditions common to EM and MD tensile loadings were responsible for the significant formability improvement compared with QS tensile loading.In particular,the inertial effect was dominant.The different deformation conditions that distinguish EM tensile loading from MD tensile loading resulted in the marginal improvement in formability.This was caused by the absence of a sustaining contact force at the later deformation stage and the lower strain rate.The body force exerted little influence on the formability improvement,and the thermal effect under the two dynamic tensile loadings was negligible.
基金supported by the National Key Basic Research Program (Nos. 2009CB118506, 2004CB117205, and 2002CB111304)the Natural Science Foundation of China (No. 30330390)+1 种基金the Knowledge Innovation Program (KIP) key project from the Chinese Academy of Sciences (No. KSCX1-YW-03)the National Science and Tech-nology Supporting Program (No. 2006GB24910466)
文摘High light induced photooxidation （HLIP） usually leads to leaf premature senescence and causes great yield loss in winter wheat. In order to explore the genetic control of wheat tolerance to HLIP stress, a quantitative trait loci （QTL） analysis was conducted on a set of doubled haploid population, derived from two winter wheat cultivars. Actual values of chlorophyll content （Chl）, minimum fluorescence level （Fo）, maximum fluorescence level （Fm）, and the maximum quan^m efficiency of photosystem II （Fv/Fm） under both HLIP and non-stress conditions as well as the ratios of HLIP to non-stress were evaluated. HLIP considerably reduced Chl, Fm, and Fv/Fm, but in- creased Fo, compared with that under non-stress condition. A total of 27, 16, and 28 QTLs were associated with the investigated traits under HLIP and non-stress and the ratios of HLIP to non-stress, respectively. Most of the QTLs for the ratios of HLIP to non-stress collocated or nearly linked with those detected under HLIP condition. HLIP-induced QTLs were mapped on 15 chromosomes, involving in 1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4D, 5B, 6A, 6B, 7A, and 7D while those expressed under non-stress condition involved in nine chromosomes, includ- ing 1B, 1D, 2A, 2B, 3B, 4A, 5A, 5B, and 7A. The expression patterns of QTLs under HLIP condition were different from that under non-stress condition except for six loci on five chromosomes. The phenotypic variance explained by individual QTL ranged from 5.0% to 19.7% under HLIP, 8.3% to 20.8% under non-stress, and 4.9% to 20.2% for the ratios of HLIP to non-stress, respectively. Some markers, for example, Xgwm192 and WMC331 on 4D regulating Chl, Fo, Fm, and Fv/Fm under HLIP condition, might be used in marker assistant selection.
基金supports from the National Natural Science Foundation of China(U1737212and U1637102)the Research Fund of the State Key Laboratory of Solidification Processing(NWPU,China)(Grant No.149-QZ-2016)+1 种基金the Fundamental Research Funds for the Central Universities(3102017jc03009)The Analytical&Testing Center at Northwestern Polytechnical University is also acknowledged for the experimental support on this work
文摘The microstructural evolution of a Ni-based superalloy under interrupted hot compressive deformation with different cooling rates in the inter-pass stage is investigated. It is found that metadynamic recrystallization(MDRX) in the inter-pass stage is more sensitive to the accumulated strain than the deformation temperature which is above the recrystallization temperature. The variations of both the grain distribution and the texture intensity caused by MDRX during the interpass stage result in variations of the yield stress(YS) and the work hardening(WH) rate in each stage. Results also show that the MDRX process in the inter-pass stage has a considerable influence on the final microstructure of three-pass compression. The final grain distribution is more uniform,and the compression texture gradually transforms into recrystallization texture with an increasing degree of MDRX. In order to predict the MDRX fraction in the inter-pass cooling stage, a modified kinetic equation is established, which can reasonably predict the MDRX behavior under multi-pass compression with different conditions in the inter-pass stage. Meanwhile, the influence of the interpass cooling stage on the mechanism of dynamic recrystallization(DRX) is studied. It is universally acknowledged that the discontinuous dynamic recrystallization(DDRX) process is the major deformation mechanism for the Ni-based superalloy. However, the continuous dynamic recrystallization(CDRX) process is promoted in the compression stage with a decrease of the cooling rate in each inter-pass stage.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA08030105)Key Programs of the Chinese Academy of Sciences (KFZD-SW112)STS Project of Chinese Academy of Sciences (KFJ-STS-ZDTP-024)
文摘Xiaoyan 60(XY60) is a new wheat variety bred in the laboratory of Zhensheng Li.After salt treatment, seedlings of XY60 maintain green leaves and produce longer roots than the high yielding cultivar Zhongmai 175(ZM175).To explain these different phenotypes we carried out an RNA-Seq analysis using 12 samples from three tissues of both varieties subjected to salt and control treatments.By comparing data from the salt treated plants with the control, 703, 979, and 1197 differentially expressed genes(DEGs) were detected in new leaves, old leaves, and roots of XY60, respectively.The corresponding numbers for ZM175 were 613, 1401, and 1301.The most significantly enriched Gene Ontology(GO) terms and KEGG pathways were associated with polyunsaturated fatty acid(PUFA) metabolism in both new and old leaves from XY60.They were associated with photosynthesis and energy metabolism in ZM175.The most significantly enriched KEGG pathway in roots of both varieties was “glucosinolate biosynthesis”.In addition, jasmonic acid(JA) concentration in XY60 was higher than in ZM175, although it increased significantly in both varieties following salt treatment.Trends in relative expression levels of AOS, MYC2, and JAZ revealed by qRT-PCR were concordant with those from RNA-Seq.Our results suggest that PUFAs may contribute to salt tolerance in common wheat by enhancing the photosynthetic system and JA-related pathways.
基金supported by a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,2014-37)
文摘Differentially expressed genes are thought to regulate the development and progression of oral squamous cell carcinomas （OSCC）. The purpose of this study was to screen differentially expressed mRNAs in OSCC and matched paraneoplastic normal tissues, and to explore the intrinsic mechanism of OSCC development and progres- sion. We obtained the differentially expressed mRNA expression profiles in 10 pairs of fresh-frozen OSCC tissue specimens and matched paraneoplastic normal tissue specimens by high-throughput RNA sequencing. By using Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analyses, the functional significance of the differentially expressed genes were analyzed. We identified 1,120 sig- nificantly up-regulated mRNAs and 178 significantly down-regulated mRNAs in OSCC, compared to normal tissue. The differentially expressed mRNAs were involved in 20 biological processes and 68 signal pathways. Compared to adjacent normal tissue, the expression of MAGEAll was up-regulated; TCHH was down-regulated. These find- ings were verified by real-time PCR. These differentially expressed mRNAs may function as oncogenes or tumor suppressors in the development and progression of OSCC. This study provides novel insights into OSCC. However, further work is needed to determine if these differentially expressed mRNAs have potential roles as diagnostic bio- markers and candidate therapeutic targets for OSCC.
基金financially supported by the National Key R&D Program of China(2021YFB3802200)the National Natural Science Foundation of China(No.51801136)+2 种基金the Tianjin Natural Science Foundation of China(No.18JCYBJC41800)the Tianjin science and technology project(Nos.18ZXJMTG00300,20ZYJDJC00100)the Discovery Early Career Researcher Award(DECRA,No.DE180101478)of the Australian Research Council。
文摘High-performance batteries with high density and low cost are needed for the development of largescale energy storage fields such as electric vehicles and renewable energy systems.The anode with threedimensional(3D)nanoarchitecture is one of the most attractive candidates for high-performance lithiumion batteries(LIBs)and sodium-ion batteries(SIBs)due to its efficient electron/ion transport and high active material mass loading.Although some important breakthroughs have been made in 3D nanoarchitecture anode materials,more improvements are still needed for high cycling stability and high energy density.Herein,the latest research progress of 3D nanoarchitecture anode materials for LIBs and SIBs is reviewed,including nanoporous metal,nanoporous graphene,and their derived foams.Specifically,the storage properties of Li/Na ions,the kinetics of ion/electron transport,and specific chemical interactions are discussed based on the structure design.In addition,the research strategies and structural characteristics of 3D nanoarchitecture anode materials are summarized,providing a reference for the further development of LIBs and SIBs.Meanwhile,the future research directions of LIBs and SIBs have also prospected.
文摘Background: Sialic acids are a family of ninecarbon sugar compounds with carboxylic acyl derivatives. It exists in bacteria, fish, mammals and other living organisms, participates in and regulates many important life events, such as cell recognition, membrane flow, endocytosis and so on. Sialic acid is usually located in the outermost layer of the sugar part of the cell membrane and the key positions of secreted glycoconjugates (glycolipids, glycoprotein and lipopolysaccharide). Sialic acid (Sia) is an important material foundation for variety of the structure and founction of glycoconjugates. Sia has been known as nearly 50 members, including N-acetylneuraminic acid (Neu5Ac), N-glycoulylneuraminic acid (Neu5Gc) and deaminoneuraminic acid (KDN) as its core monomer. The rest of the sialic acids are derived from these three monomers. The contents of Sia in Chinese food products are unknown. Objective: To determine the contents of Sia in raw and cooked red meat, seafood, poultry and so on. Design: The following food products were purchased from a Chinese supermarket: pork, beef, lamb, salmon, cod, tuna, cow milk, cheese, butter, duck, chicken and chicken eggs. Human milk was collected from Xiamen Maternity and Child Health Care Hospital (Xiamen, China). All tissues were homogenized and hydrolyzed with 0.05 M, 0.1 M and 0.2 M TFA for 150 min at 80°C in dark, respectively. The concentrations of Neu5Ac, Neu5Gc and KDN were determined by using HPLC with fluorescence detector. Results: The contents of total Sia (μg/g tissue or μg/mL liquid sample) in Chinese raw meat were highest in lamb (269.60), followed by pork (254.88), duck (200.63), chicken (162.86) and beef (88.03). The percentages of Neu5Gc were 36.08%, 26.48%, 0%, 0% and 28.40%, respectively. Cod contained higher levels of Sia (171.63) than salmon (104.43) and tuna (77.98). Only Neu5Ac was 50 found in detected aquatic product. Egg yolk contained the highest level of Sia (682.04), and a higher level of Sia (390.67) was found in the egg white. Also our result showed that human milk contained extremely high level of Sia (602.55). Neu5Ac was the predominant form of Sia in all the deteced samples. KDN was found in cow milk only among the samples, the content was 1.14 μg/g. Conclusion: The highest content of Sia in examined Chinese foods was found in 56 eggs, followed by lamb, pork, duck, cod, chicken, salmon, beef and tuna. Knowledge of the Sia content in conventional foods may help us to better understand possible medical disorders involving the uptake of the “non-human” Neu5Gc from our diet.
基金supported by the Ministry of Science and Technology of China (No. 2014DFA31540)Chinese Academy of Sciences (No. SAJC201305)the Bill & Melinda Gates Foundation to Cornell University for the Borlaug Global Rust Initiative (BGRI) Durable Rust Resistance in Wheat (DRRW) Project
文摘Ug99, also designated as TFKSK, is a race of Puccinia graminis Pers.：Pers f. sp. tn＇tici Eriks. and E. Henn （Pgt） with broad virulence to wheat. It is the first known Pgt race possessing virulence to Sr31, a stem rust resistance （Sr） gene deployed in wheat varieties world- wide （Singh et al., 2011 ）. Since the first detection of TFKSK in 1998, a total of 13 Ug99 variants have been identified in several African countries.
基金co-supported by the National Natural Science Foundation of China(No.91748209,11402229)Natural Science Foundation of Zhejiang Province(No.LY17A020003)the Fundamental Research Funds for the Central Universities(No.2018QNA4054,2019QNA4057)。
文摘A novel soft robotic arm(SRA)composed of two soft extensible arms(SEAs)and a soft bendable joint(SBJ)for space capture systems is presented in this paper.A diamond origami pattern was applied in the design of the SEAs,and large deformations of the SEAs in positive pressure were simulated using the nonlinear finite element method.A kinematic model of the SRA using the Denavit–Hartenberg method based on the assumption of constant curvatures was proposed.A closed-loop model-free control system based on a PID controller was developed using real-time data from a vision sensor system.The kinematic model and closed-loop model-free control system are experimentally evaluated on an SRA prototype by four experiments.The experimental results demonstrate that the derived kinematic model can finely describe the movement of the SRA and that the closed-loop control system can control the SRA to reach the desired destination or trajectory within an acceptable error and performs well in long-term repeated operations.
基金the National Natural Science Foundation of China under Grant Nos.50774026,50875059 and 51174064
文摘The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles （soluble only in liquid） could pin at grain and subgrain boundary to make the alloy difficultly recrystallise. In this work, a novel multistep reheating regime is developed for recrystallisation and partial melting （RAP） route to prepare fine spheroidal microstructure of semi-solid AI-Zn- Mg-Cu alloy. After reheating to 665 ℃, holding for 4 min and subsequent isothermally holding at 620 ℃ with total heating time of 15 min, fine spheroidal microstructures with grain size of-40 μm were prepared without remained unrecrystallised grains and directionality, which are much finer than the conventionally obtained microstructures （-100 μm）.
基金supported by the Natural Science Foundation of China (No. 31571644)the National Key Basic Research Program (No. 2015CB150106)the Ministry of Science and Technology of China (2014DFA31540)
文摘Stem rust, caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn. (Pgt), is a destructive wheat disease and has the potential to cause significant yield losses (Olivera et al., 2015;Soko et al., 2018). The emergence of Pgt race TTKSK, virulent to the widely deployed stem rust resistance gene Sr31 and originally named as isolate Pgt-Ug99 (Pretorius et al., 2000).
基金the National Science Fund for Distinguished Young Scholars(No.52225505)the National Sci-ence and Technology Major Project(No.J2019-VII-0014-0154)+1 种基金the National Natural Science Foundation of China(No.52005412)the Open Research Fund of State Key Laboratory of Precision Man-ufacturing for Extreme Service Performance(No.Kfkt2023-12)for financial supports given to this research.
文摘Mechanical properties of TC17 titanium alloy undergo a significant reduction after linear friction welding(LFW),of which the strength and ductility are hard to be improved simultaneously by traditional aging heat treatment(AHT),seriously limiting the application of LFW in the manufacturing of TC17 titanium alloy blisks.To this end,the present work proposes to use electric pulse treatment(EPT)to enhance the strength and ductility of TC17 LFW joints simultaneously by improving its microstructure.The results show that,in comparison to the uneven distribution ofαphases in the welding zone(WZ),heat-affected zone(HAZ),and base metal(BM)zone after AHT,EPT can selectively homogenize theαphase distribution of WZ and HAZ without impacting the BM.The selective effect of EPT is reflected as the synergistic influence of the local Joule heating effect and the electron wind effect,which promotes the diffusion ofβphase stabilizing element Mo and leads to a competitive precipitation ofβphase andαphase in theαphase transition temperature range.The ratio ofαphase toβphase in the WZ and HAZ finally approaches an equilibrium point which is similar to that of BM,leading to a uniform distribution ofαphase and realizing the synergy of strength-ductility of LFW joint:the maximum strength increase observed is 12.9%,accompanied by a corresponding elongation increase of 122%(by AHT&EPT),and the maximum plasticity improvement is 185%,accompanied by a corresponding strength increase of 4.3%(by EPT for 1 h).This study provides essential insights for improving the strength and ductility of LFW TC17 titanium alloy blisks and enhancing the applications of LFW in aeroengine components.
基金Project supported by the National Natural Science Foundation of China(51401028)
文摘This paper reports crystal structures, magnetic properties and thermal stability of TbCu7-type Sm（8.5）Fe（（85.8-x）Co（4.5）Zr（1.2）Nbx（x = 0-1.8） melt-spun compounds and their nitrides, investigated by means of X-ray diffraction, vibrating sample magnetometer, flux meter and transmission electron microscope. It is found that the lattice parameter ratio c/a of TbCu7-type crystal structure increases with Nb substitution, which indicates that the Nb can increase the stability of the metastable phase in the Sm-Fe ribbons. Nb substitution impedes the formation of magnetic soft phase a-Fe in which reversed domains initially form during the magnetization reversal process. Meanwhile, Nb substitution refines grains and leads to homogeneous micro structure with augmented grain boundaries. Thus the exchange coupling pining field is enhanced and irreversible domain wall propagation gets suppressed. As a result, the magnetic properties are improved and the irreversible flux loss of magnets is notably decreased. A maximum value 771.7 kA/m of the intrinsic coercivity H（cj） is achieved in the 1.2 at% substituted samples.The irreversible flux loss for 2 h exposure at 120 ℃ declines from 8.26% for Nb-free magnets to 6.32% for magnets with 1.2 at% Nb substitution.
