Maize seedling blight caused by Fusarium verticillioides is a widely occurring maize disease,but the genetics and mechanisms of resistance are not well understood.In this study,GWAS performed by MLM and 3VmrMLM identi...Maize seedling blight caused by Fusarium verticillioides is a widely occurring maize disease,but the genetics and mechanisms of resistance are not well understood.In this study,GWAS performed by MLM and 3VmrMLM identified 40 and 20 QTNs,associated with seedling blight resistance.These methods identified 49 and 36 genes,respectively.Functional verification of candidate gene ZmSBR1 identified by both methods showed that the resistance of a mutant line to seedling blight decreased by 0.37 grade points after inoculation with F.verticillioides,compared with the WT.The length of the stem rot lesion caused by F.verticillioides increased by 86%in mutant seedlings,and the relative length of the adult plant stalk rot increased by 35%in mutant plants compared to the wild type after inoculation with Fusarium graminearum.Transcriptome analysis showed that expression of defense-related genes after inoculation was down-regulated in the mutant compared to the wild type,synthesis of secondary metabolites associated with resistance was reduced,and the immune response triggered by PAMP decreased,resulting in decreased resistance of mutant maize seedlings.Candidate gene association analysis showed that most maize inbred lines carried the susceptible haplotype.A functional PCR marker was developed.The results demonstrated that ZmSBR1 conferred resistance to multiple Fusarium diseases at the seedling and adult growth stages and had important application value in breeding.展开更多
Benzoxazinoids(BXDs)are a class of plant secondary metabolites that play pivotal roles in plant defense against pathogens and pests,as well as in allelopathy.This review synthesizes recent advances in our understandin...Benzoxazinoids(BXDs)are a class of plant secondary metabolites that play pivotal roles in plant defense against pathogens and pests,as well as in allelopathy.This review synthesizes recent advances in our understanding of the structural and functional diversity of BXDs,the independent evolutionary trajectories of their biosynthetic pathways across different plant species,their metabolic transformations in target organisms,and the opportunities and challenges of optimizing BXD biosynthesis in crops through metabolic engineering.Compared with monocotyledons,dicotyledons employ a more diverse set of enzymes to catalyze the core reactions of BXD biosynthesis.This functional divergence—yet biochemical convergence—between monocotyledons and dicotyledons exemplifies the convergent evolution of BXD biosynthetic pathways in plants.BXDs act not only as potent antifeedants,insecticides,and antimicrobials but also function as signaling molecules that induce callose deposition and activate systemic immunity,thereby enhancing plant resistance to biotic stress.Furthermore,BXDs shape the rhizosphere by modulating microbial communities through species-specific antimicrobial activities and microbial detoxification mechanisms,ultimately exerting allelopathic effects that alter soil chemistry and nutrient dynamics.The translational potential of BXDs is increasingly recognized by synthetic biology approaches,including artificial intelligence-driven enzyme optimization,heterologous pathway engineering,and gene-editing to enhance crop resistance.Despite these promising prospects,challenges remain in balancing metabolic trade-offs and mitigating ecological risks associated with persistent accumulation of BXDs.Future research integrating multi-omics,evolutionary genomics,and microbiome studies will be essential to fully harness BXDs for sustainable crop improvement and reduced reliance on synthetic agrochemicals.展开更多
Maize(Zea mays L.)is an indispensable crop worldwide for food,feed,and bioenergy production.Fusarium verticillioides(F.verticillioides)is a widely distributed phytopathogen and incites multiple destructive diseases in...Maize(Zea mays L.)is an indispensable crop worldwide for food,feed,and bioenergy production.Fusarium verticillioides(F.verticillioides)is a widely distributed phytopathogen and incites multiple destructive diseases in maize:seedling blight,stalk rot,ear rot,and seed rot.As a soil-,seed-,and airborne pathogen,F.verticillioides can survive in soil or plant residue and systemically infect maize via roots,contaminated seed,silks,or external wounds,posing a severe threat to maize production and quality.Infection triggers complex immune responses:induction of defense-response genes,changes in reactive oxygen species,plant hormone levels and oxylipins,and alterations in secondary metabolites such as flavonoids,phenylpropanoids,phenolic compounds,and benzoxazinoid defense compounds.Breeding resistant maize cultivars is the preferred approach to reducing F.verticillioides infection and mycotoxin contamination.Reliable phenotyping systems are prerequisites for elucidating the genetic structure and molecular mechanism of maize resistance to F.verticillioides.Although many F.verticillioides resistance genes have been identified by genome-wide association study,linkage analysis,bulkedsegregant analysis,and various omics technologies,few have been functionally validated and applied in molecular breeding.This review summarizes research progress on the infection cycle of F.verticillioides in maize,phenotyping evaluation systems for F.verticillioides resistance,quantitative trait loci and genes associated with F.verticillioides resistance,and molecular mechanisms underlying maize defense against F.verticillioides,and discusses potential avenues for molecular design breeding to improve maize resistance to F.verticillioides.展开更多
In genomic selection, prediction accuracy is highly driven by the size of animals in the reference population(RP).Combining related populations from different countries and regions or using a related population with l...In genomic selection, prediction accuracy is highly driven by the size of animals in the reference population(RP).Combining related populations from different countries and regions or using a related population with large size of RP has been considered to be viable strategies in cattle breeding. The genetic relationship between related populations is important for improving the genomic predictive ability. In this study, we used 122 French bulls as test individuals. The genomic estimated breeding values(GEBVs) evaluated using French RP, America RP and Chinese RP were compared.The results showed that the GEBVs were in higher concordance using French RP and American RP compared with using Chinese population. The persistence analysis, kinship analysis and the principal component analysis(PCA) were performed for 270 French bulls, 270 American bulls and 270 Chinese bulls to interpret the results. All the analyses illustrated that the genetic relationship between French bulls and American bulls was closer compared with Chinese bulls. Another reason could be the size of RP in China was smaller than the other two RPs. In conclusion, using RP of a related population to predict GEBVs of the animals in a target population is feasible when these two populations have a close genetic relationship and the related population is large.展开更多
The frequent occurrence of hitherto unknown phase Pre-θ′-2 and unusual 1.5 cθ′thick θ′precipitate was observed by atomic-resolution scanning transmission electron microscopy in the well-studied Al-Cu alloys. Thi...The frequent occurrence of hitherto unknown phase Pre-θ′-2 and unusual 1.5 cθ′thick θ′precipitate was observed by atomic-resolution scanning transmission electron microscopy in the well-studied Al-Cu alloys. This phenomenon is associated with heterogeneous precipitate nucleation and growth on preexisting dislocations introduced by slight deformation prior to aging. In this study, the precise structure details of Pre-θ′-2 was determined by atomic scale imaging, image simulation based on image forming theories and first principle calculations. Pre-θ′-2 has a well-defined ordered structure sandwiched between two 2 aAl(~1.5 cθ′) spaced Cu layers on {200}Alplanes. The strong structural similarities between Pre-θ′-2 and 1.5 cθ′ thick θ′ in terms of interfacial structure and thickness, coupled with energetic calculations and preliminary in-situ observations, lead us to propose a new precipitation path toward key strengthening phase θ′展开更多
It is generally believed that a major cause of motor dysfunction is the impairment in neural network that controls movement. But little is known about the underlying mechanisms of the impairment in cortical control or...It is generally believed that a major cause of motor dysfunction is the impairment in neural network that controls movement. But little is known about the underlying mechanisms of the impairment in cortical control or in the neural connections between cortex and muscle that lead to the loss of motor ability. So understanding the functional connection between motor cortex and effector muscle is of utmost importance. Previous study mostly relied on cross-correlation, coherence functions or model based approaches such as Granger causality or dynamic causal modeling. In this work the information transfer index (ITI) was introduced to describe the information flows between motor cortex and muscle. Based on the information entropy the ITI can detect both linear and nonlinear interaction between two signals and thus represent a very comprehensive way to define the causality strength. The applicability of ITI is investigated based on simulations and electroencephalogram (EEG), surface electromyography (sEMG) recordings in a simple motor task.展开更多
In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-...In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-Ga_(2)O_(3) film with full width at half maximum(FWHM)of 0.66°was achieved.A metal−semiconductor−metal(MSM)solar-blind photodetector(PD)was fabricated based on theβ-Ga_(2)O_(3) film.Ultrahigh responsivity of 1422 A/W@254 nm and photo-to-dark current ratio(PDCR)of 10^(6) at 10 V bias were obtained.The detectivity of 2.5×10^(15) Jones proved that the photodetector has outstanding performance in detecting weak signals.Moreover,the photodetector exhibited superior wavelength selectivity with rejection ratio(R_(250 nm)/R_(400 nm))of 105.These results indicate that the two-step method is a promising approach for preparation of high-qualityβ-Ga_(2)O_(3)films for high-performance solar-blind photodetectors.展开更多
Artificial ageing above 165℃directly after quenching induces the formation of^50 nm wide precipitatefree zone(PFZ)and^100 nm wide precipitate-sparse zone(PSZ)consisting of coarse precipitates with a gradient in size ...Artificial ageing above 165℃directly after quenching induces the formation of^50 nm wide precipitatefree zone(PFZ)and^100 nm wide precipitate-sparse zone(PSZ)consisting of coarse precipitates with a gradient in size and density toward the grain center in a commercial Al-Zn-Mg-Cu alloy.With the grain size decreasing,the fraction of PFZ and PSZ in a grain becomes larger and could even occupy the entire volume of the grain.This undesirable microstructure near the grain boundary is mitigated substantially by natural pre-ageing,leading to an exceptional enhancement of the age hardening potential at elevated temperatures.Natural ageing could fundamentally alter the precipitation near grain boundary,and is a promising method to optimize the precipitation hardening in high strength aluminum alloys with unconventionally small grains.展开更多
The high-strength Al-Zn-Mg-Cu alloy provides much better dent resistance and weight-reduction potential compared to the conventional Al alloys used for the automobile body panels.However,natural ageing(NA)significantl...The high-strength Al-Zn-Mg-Cu alloy provides much better dent resistance and weight-reduction potential compared to the conventional Al alloys used for the automobile body panels.However,natural ageing(NA)significantly reduces the formability of Al-Zn-Mg-Cu alloy.The reversion of natural ageing has been systematically investigated by hardness test,tensile test,differential scanning calorimetry(DSC)and transmission electron microscopy(TEM).Substantial reversion of natural ageing and thus hardness decrease occurs immediately upon thermal treatment at 120–210℃in an Al-Zn-Mg-Cu alloy.Although the hardness of the most reverted state decreases with increasing temperature,the lowest hardness is still higher than the as-quenched state by 30 HV.As revealed by the complementary DSC and TEM observations,this is ascribed to the synchronization of the dissolution and the re-precipitation of the solutes in the NA clusters during reversion ageing.Reversion at 180–210℃for less than 30 s leads to a hardness decline of 40 HV.The hardening kinetics during NA after reversion is slower than that during first-time NA due to the reduced vacancy concentration.Artificial ageing at 180℃for 30 min after secondary NA of less than 24 h induces intensive precipitation of plate-like pre-ηphases and a giant strength increase of 188–204 MPa.Potential use of high strength Al-Zn-Mg-Cu alloy in automobile body panels could be realized by appropriate reversion treatment improving the formability and the quick bake hardening response.展开更多
Background:Genotyping by sequencing(GBS)is a robust method to genotype markers.Many factors can influence the genotyping quality.One is that heterozygous genotypes could be wrongly genotyped as homozygotes,dependent o...Background:Genotyping by sequencing(GBS)is a robust method to genotype markers.Many factors can influence the genotyping quality.One is that heterozygous genotypes could be wrongly genotyped as homozygotes,dependent on the genotyping depths.In this study,a method correcting this type of genotyping error was demonstrated.The efficiency of this correction method and its effect on genomic prediction were assessed using simulated data of livestock populations.Results:Chip array(Chip)and four depths of GBS data was simulated.After quality control(call rate≥0.8 and MAF≥0.01),the remaining number of Chip and GBS SNPs were both approximately 7,000,averaged over 10 replicates.GBS genotypes were corrected with the proposed method.The reliability of genomic prediction was calculated using GBS,corrected GBS(GBSc),true genotypes for the GBS loci(GBSr)and Chip data.The results showed that GBSc had higher rates of correct genotype calls and higher correlations with true genotypes than GBS.For genomic prediction,using Chip data resulted in the highest reliability.As the depth increased to 10,the prediction reliabilities using GBS and GBSc data approached those using true GBS data.The reliabilities of genomic prediction using GBSc data were 0.604,0.672,0.684 and 0.704 after genomic correction,with the improved values of 0.013,0.009,0.006 and 0.001 at depth=2,4,5 and 10,respectively.Conclusions:The current study showed that a correction method for GBS data increased the genotype accuracies and,consequently,improved genomic predictions.These results suggest that a correction of GBS genotype is necessary,especially for the GBS data with low depths.展开更多
Beta-gallium oxide(β-Ga_(2)O_(3))thin films were deposited on c-plane(0001)sapphire substrates with different mis-cut angles along<>by metal-organic chemical vapor deposition(MOCVD).The structural properties an...Beta-gallium oxide(β-Ga_(2)O_(3))thin films were deposited on c-plane(0001)sapphire substrates with different mis-cut angles along<>by metal-organic chemical vapor deposition(MOCVD).The structural properties and surface morphology of as-grownβ-Ga_(2)O_(3)thin films were investigated in detail.It was found that by using thin buffer layer and mis-cut substrate technology,the full width at half maximum(FWHM)of the()diffraction peak of theβ-Ga_(2)O_(3)film is decreased from 2°on c-plane(0001)Al_(2)O_(3)substrate to 0.64°on an 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.The surface root-mean-square(RMS)roughness can also be improved greatly and the value is 1.27 nm for 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.Room temper-ature photoluminescence(PL)was observed,which was attributed to the self-trapped excitons formed by oxygen and gallium vacancies in the film.The ultraviolet-blue PL intensity related with oxygen and gallium vacancies is decreased with the increas-ing mis-cut angle,which is in agreement with the improved crystal quality measured by high resolution X-ray diffraction(HR-XRD).The present results provide a route for growing high qualityβ-Ga_(2)O_(3)film on Al_(2)O_(3)substrate.展开更多
The improvement of post-form properties without compromising creep formability has been a critical issue in creep age forming of aluminum alloy component. A pretreatment process incorporating artificial pre-aging at 1...The improvement of post-form properties without compromising creep formability has been a critical issue in creep age forming of aluminum alloy component. A pretreatment process incorporating artificial pre-aging at 165 °C for 6 h/12 h/24 h followed by pre-strain(3%–9%)has been developed. This method not only evidently improves the strength but also accelerates the creep deformation during creep aging of an Al-Cu alloy. A strength increase of 50 MPa with a slight decrease of ductility relative to the 9% pre-strained alloy is acquired in the alloy artificially pre-aged for 24 h regardless of the pre-strain level(3%–9%). Artificial aging for 24 h prior to 3%pre-strain enables an increase of creep strain by 30%. The creep strain in the alloy artificially preaged for 24 h and pre-strained by 6% is comparable to that in the alloy pre-strained by 9%. The strength and ductility in the alloy artificially pre-aged for 6 h/12 h and pre-strained by 3% are even slightly higher than those in the alloy purely pre-strained by 9%. The characterizations by transmission electron microscopy reveal that pre-aging at 165 °C could promote the accumulation of dislocations during pre-straining due to the pinning effect of pre-existing Guinier-Preston zones(GP zones)/θ’’phases and thus expedite the creep deformation in respect to the pure pre-straining treatment. The enhanced precipitation of θ’phases at these pinned dislocations contributes to the improved strength after creep aging. The results demonstrate applying artificial pre-aging before pre-straining is an efficient strategy to elevate the creep aging response in Al alloys.展开更多
Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming.The stress-relaxation ageing(SRA)behavior and mechanical properties of a commercial 2219 aluminum a...Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming.The stress-relaxation ageing(SRA)behavior and mechanical properties of a commercial 2219 aluminum alloy largely pre-deformed(LPD)by 80%have been systematically investigated.The stress relaxation ratio of the LPD alloy reaches approximately 94%regardless of the initial stress(50–350 MPa)after ageing for 12 h at 140°C.This relaxation ratio is about 2.9 and 1.8 times that in the T4 tempered alloy(27.6%under 50 MPa and 31.5%under 150 MPa)and T3 tempered alloy(37.6%under 50 MPa and 51.2%under 150 MPa),respectively.The microstructures,comprised of GP zones/θ'precipitates plus dislocation tangles,and tensile properties in the stress-relaxation-aged LPD alloys remain basically invariant with different initial stresses,as is vital importance for property consistency at different locations of the formed part.Under the same SRA condition,the LPD alloy has an increase of 150–230 MPa in yield strength relative to T3/T4 tempered alloy and obtains a uniform elongation of about 8%.A simple dislocation-based constitutive model accurately describing stress relaxation enhanced by the high dislocation density is established and embedded in the finite element package through a user subroutine.Simulations and experimental verifications show the LPD alloy sheet parts exhibit a nearly zero springback(<5%)after unloading in contrast to the springback larger than 65%in the T3/T4 alloy sheet parts under the same condition.Our findings demonstrate the high-dislocation-density-enhanced SRA response enables a high-performance springback-free age forming of Al alloy sheet.展开更多
Heavy doped n-typeβ-G_(2)O_(3)(HD-G_(2)O_(3))was obtained by employing Si ion implantation technology on unintentionally dopedβ-G_(2)O_(3)single crystal substrates.To repair the G_(2)O_(3)lattice damage and activate...Heavy doped n-typeβ-G_(2)O_(3)(HD-G_(2)O_(3))was obtained by employing Si ion implantation technology on unintentionally dopedβ-G_(2)O_(3)single crystal substrates.To repair the G_(2)O_(3)lattice damage and activate the Si after implantation,the implanted substrates were annealed at 950℃,1000℃,and 1100℃,respectively.High-resolution X-ray diffraction and high-resolution transmission electron microscopy show that the ion-implanted layer has high lattice quality after high-temperature annealing at 1000℃.The minimum specific contact resistance is 9.2×10^(-5)Ω·cm^(2),which is attributed to the titanium oxide that is formed at the Ti/G_(2)O_(3)interface via rapid thermal annealing at 480℃.Based on these results,the lateralˇ-G_(2)O_(3)diodes were prepared,and the diodes exhibit high forward current density and low specific on-resistance.展开更多
基金supported by grants from the National Key Research and Development Program Project of China(2022YFD1201803)Research on Resistance Genetics of Maize Root Rot Disease,State Key Laboratory of Agronomy College,Henan Agricultural University,China(39990073/111)。
文摘Maize seedling blight caused by Fusarium verticillioides is a widely occurring maize disease,but the genetics and mechanisms of resistance are not well understood.In this study,GWAS performed by MLM and 3VmrMLM identified 40 and 20 QTNs,associated with seedling blight resistance.These methods identified 49 and 36 genes,respectively.Functional verification of candidate gene ZmSBR1 identified by both methods showed that the resistance of a mutant line to seedling blight decreased by 0.37 grade points after inoculation with F.verticillioides,compared with the WT.The length of the stem rot lesion caused by F.verticillioides increased by 86%in mutant seedlings,and the relative length of the adult plant stalk rot increased by 35%in mutant plants compared to the wild type after inoculation with Fusarium graminearum.Transcriptome analysis showed that expression of defense-related genes after inoculation was down-regulated in the mutant compared to the wild type,synthesis of secondary metabolites associated with resistance was reduced,and the immune response triggered by PAMP decreased,resulting in decreased resistance of mutant maize seedlings.Candidate gene association analysis showed that most maize inbred lines carried the susceptible haplotype.A functional PCR marker was developed.The results demonstrated that ZmSBR1 conferred resistance to multiple Fusarium diseases at the seedling and adult growth stages and had important application value in breeding.
基金supported by the Excellent Youth Science Project of Henan Natural Science Foundation(242300421110)the National Natural Science Foundation of China(32372129,32272038)Henan Provincial Nature Foundation Project(242300420151).
文摘Benzoxazinoids(BXDs)are a class of plant secondary metabolites that play pivotal roles in plant defense against pathogens and pests,as well as in allelopathy.This review synthesizes recent advances in our understanding of the structural and functional diversity of BXDs,the independent evolutionary trajectories of their biosynthetic pathways across different plant species,their metabolic transformations in target organisms,and the opportunities and challenges of optimizing BXD biosynthesis in crops through metabolic engineering.Compared with monocotyledons,dicotyledons employ a more diverse set of enzymes to catalyze the core reactions of BXD biosynthesis.This functional divergence—yet biochemical convergence—between monocotyledons and dicotyledons exemplifies the convergent evolution of BXD biosynthetic pathways in plants.BXDs act not only as potent antifeedants,insecticides,and antimicrobials but also function as signaling molecules that induce callose deposition and activate systemic immunity,thereby enhancing plant resistance to biotic stress.Furthermore,BXDs shape the rhizosphere by modulating microbial communities through species-specific antimicrobial activities and microbial detoxification mechanisms,ultimately exerting allelopathic effects that alter soil chemistry and nutrient dynamics.The translational potential of BXDs is increasingly recognized by synthetic biology approaches,including artificial intelligence-driven enzyme optimization,heterologous pathway engineering,and gene-editing to enhance crop resistance.Despite these promising prospects,challenges remain in balancing metabolic trade-offs and mitigating ecological risks associated with persistent accumulation of BXDs.Future research integrating multi-omics,evolutionary genomics,and microbiome studies will be essential to fully harness BXDs for sustainable crop improvement and reduced reliance on synthetic agrochemicals.
基金the National Natural Science Foundation of China(32201787,32201793)the Innovation Special Program of Henan Agricultural University for Science and Technology(30501044)the Special Support Fund for High-Level Talents of Henan Agricultural University(30501302).
文摘Maize(Zea mays L.)is an indispensable crop worldwide for food,feed,and bioenergy production.Fusarium verticillioides(F.verticillioides)is a widely distributed phytopathogen and incites multiple destructive diseases in maize:seedling blight,stalk rot,ear rot,and seed rot.As a soil-,seed-,and airborne pathogen,F.verticillioides can survive in soil or plant residue and systemically infect maize via roots,contaminated seed,silks,or external wounds,posing a severe threat to maize production and quality.Infection triggers complex immune responses:induction of defense-response genes,changes in reactive oxygen species,plant hormone levels and oxylipins,and alterations in secondary metabolites such as flavonoids,phenylpropanoids,phenolic compounds,and benzoxazinoid defense compounds.Breeding resistant maize cultivars is the preferred approach to reducing F.verticillioides infection and mycotoxin contamination.Reliable phenotyping systems are prerequisites for elucidating the genetic structure and molecular mechanism of maize resistance to F.verticillioides.Although many F.verticillioides resistance genes have been identified by genome-wide association study,linkage analysis,bulkedsegregant analysis,and various omics technologies,few have been functionally validated and applied in molecular breeding.This review summarizes research progress on the infection cycle of F.verticillioides in maize,phenotyping evaluation systems for F.verticillioides resistance,quantitative trait loci and genes associated with F.verticillioides resistance,and molecular mechanisms underlying maize defense against F.verticillioides,and discusses potential avenues for molecular design breeding to improve maize resistance to F.verticillioides.
基金supported by the earmarked fund for China Agriculture Research System(CARS-36)the National Natural Science Foundation of China(31671327,31701077,31371258)+2 种基金the Program for Changjiang Scholar and Innovation Research Team in University(Grant No.IRT1191)Anhui Science and Technology Key Project(17030701008)Anhui Academy of Agricultural Sciences Key Laboratory Project(18S0404)
文摘In genomic selection, prediction accuracy is highly driven by the size of animals in the reference population(RP).Combining related populations from different countries and regions or using a related population with large size of RP has been considered to be viable strategies in cattle breeding. The genetic relationship between related populations is important for improving the genomic predictive ability. In this study, we used 122 French bulls as test individuals. The genomic estimated breeding values(GEBVs) evaluated using French RP, America RP and Chinese RP were compared.The results showed that the GEBVs were in higher concordance using French RP and American RP compared with using Chinese population. The persistence analysis, kinship analysis and the principal component analysis(PCA) were performed for 270 French bulls, 270 American bulls and 270 Chinese bulls to interpret the results. All the analyses illustrated that the genetic relationship between French bulls and American bulls was closer compared with Chinese bulls. Another reason could be the size of RP in China was smaller than the other two RPs. In conclusion, using RP of a related population to predict GEBVs of the animals in a target population is feasible when these two populations have a close genetic relationship and the related population is large.
基金financial support from the National Natural Science Foundation of China (Nos. 51601060, 51235010, 51671086)Natural Science Foundation of Hunan Province (No. 2018JJ3655)+5 种基金the Major Project for Defense Basic Preresearch Programthe National Key R&D Program of China (No. 2017YFB0306300)the National Key Basic Research Development Plan Funded Project of China (No. 2014CB046602)the Innovationdriven Plan in Central South University (No. 2015CX002)the Science and Technology Plan in Hunan Province (No. 2016RS2015)the Fundamental Research Funds for the Central Universities of Central South University (No. 1053320180612)
文摘The frequent occurrence of hitherto unknown phase Pre-θ′-2 and unusual 1.5 cθ′thick θ′precipitate was observed by atomic-resolution scanning transmission electron microscopy in the well-studied Al-Cu alloys. This phenomenon is associated with heterogeneous precipitate nucleation and growth on preexisting dislocations introduced by slight deformation prior to aging. In this study, the precise structure details of Pre-θ′-2 was determined by atomic scale imaging, image simulation based on image forming theories and first principle calculations. Pre-θ′-2 has a well-defined ordered structure sandwiched between two 2 aAl(~1.5 cθ′) spaced Cu layers on {200}Alplanes. The strong structural similarities between Pre-θ′-2 and 1.5 cθ′ thick θ′ in terms of interfacial structure and thickness, coupled with energetic calculations and preliminary in-situ observations, lead us to propose a new precipitation path toward key strengthening phase θ′
文摘It is generally believed that a major cause of motor dysfunction is the impairment in neural network that controls movement. But little is known about the underlying mechanisms of the impairment in cortical control or in the neural connections between cortex and muscle that lead to the loss of motor ability. So understanding the functional connection between motor cortex and effector muscle is of utmost importance. Previous study mostly relied on cross-correlation, coherence functions or model based approaches such as Granger causality or dynamic causal modeling. In this work the information transfer index (ITI) was introduced to describe the information flows between motor cortex and muscle. Based on the information entropy the ITI can detect both linear and nonlinear interaction between two signals and thus represent a very comprehensive way to define the causality strength. The applicability of ITI is investigated based on simulations and electroencephalogram (EEG), surface electromyography (sEMG) recordings in a simple motor task.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2020YFB2206103)。
文摘In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-Ga_(2)O_(3) film with full width at half maximum(FWHM)of 0.66°was achieved.A metal−semiconductor−metal(MSM)solar-blind photodetector(PD)was fabricated based on theβ-Ga_(2)O_(3) film.Ultrahigh responsivity of 1422 A/W@254 nm and photo-to-dark current ratio(PDCR)of 10^(6) at 10 V bias were obtained.The detectivity of 2.5×10^(15) Jones proved that the photodetector has outstanding performance in detecting weak signals.Moreover,the photodetector exhibited superior wavelength selectivity with rejection ratio(R_(250 nm)/R_(400 nm))of 105.These results indicate that the two-step method is a promising approach for preparation of high-qualityβ-Ga_(2)O_(3)films for high-performance solar-blind photodetectors.
基金the National Natural Science Foundation of China(Nos.51601060,51675538 and 11872380)the Natural Science Foundation of Hunan Province(No.2018JJ3655)+3 种基金the National Key R&D Program of China(No.2017YFB0306300)the Innovation-driven Plan in Central South University(No.2015CX002)the Science and Technology Plan in Hunan Province(No.2016RS2015)the Fundamental Research Funds for the Central Universities of Central South University(No.2018zzts154)。
文摘Artificial ageing above 165℃directly after quenching induces the formation of^50 nm wide precipitatefree zone(PFZ)and^100 nm wide precipitate-sparse zone(PSZ)consisting of coarse precipitates with a gradient in size and density toward the grain center in a commercial Al-Zn-Mg-Cu alloy.With the grain size decreasing,the fraction of PFZ and PSZ in a grain becomes larger and could even occupy the entire volume of the grain.This undesirable microstructure near the grain boundary is mitigated substantially by natural pre-ageing,leading to an exceptional enhancement of the age hardening potential at elevated temperatures.Natural ageing could fundamentally alter the precipitation near grain boundary,and is a promising method to optimize the precipitation hardening in high strength aluminum alloys with unconventionally small grains.
基金financial support from National Natural Science Foundation of China(Nos.U2032117,51675538,11872380)the National Key R&D Program of China(No.2017YFB0306300)+3 种基金Natural Science Foundation of Hunan Province(No.2018JJ3655)National Science and Technology Major Project(No.2017ZX04005001)the Fundamental Research Funds for the Central Universities of Central South University(2021zzts0638)the Innovation fund of National commercial aircraft manufacturing engineering technology centre(No.COMAC-SFGS-2019-4284)。
文摘The high-strength Al-Zn-Mg-Cu alloy provides much better dent resistance and weight-reduction potential compared to the conventional Al alloys used for the automobile body panels.However,natural ageing(NA)significantly reduces the formability of Al-Zn-Mg-Cu alloy.The reversion of natural ageing has been systematically investigated by hardness test,tensile test,differential scanning calorimetry(DSC)and transmission electron microscopy(TEM).Substantial reversion of natural ageing and thus hardness decrease occurs immediately upon thermal treatment at 120–210℃in an Al-Zn-Mg-Cu alloy.Although the hardness of the most reverted state decreases with increasing temperature,the lowest hardness is still higher than the as-quenched state by 30 HV.As revealed by the complementary DSC and TEM observations,this is ascribed to the synchronization of the dissolution and the re-precipitation of the solutes in the NA clusters during reversion ageing.Reversion at 180–210℃for less than 30 s leads to a hardness decline of 40 HV.The hardening kinetics during NA after reversion is slower than that during first-time NA due to the reduced vacancy concentration.Artificial ageing at 180℃for 30 min after secondary NA of less than 24 h induces intensive precipitation of plate-like pre-ηphases and a giant strength increase of 188–204 MPa.Potential use of high strength Al-Zn-Mg-Cu alloy in automobile body panels could be realized by appropriate reversion treatment improving the formability and the quick bake hardening response.
基金supported by the Genomic Selection in PlantsAnimals(GenSAP)research project financed by the Danish Council of Strategic Research(Aarhus,Denmark)the scholarship provided by the China Scholarship Council(CSC)
文摘Background:Genotyping by sequencing(GBS)is a robust method to genotype markers.Many factors can influence the genotyping quality.One is that heterozygous genotypes could be wrongly genotyped as homozygotes,dependent on the genotyping depths.In this study,a method correcting this type of genotyping error was demonstrated.The efficiency of this correction method and its effect on genomic prediction were assessed using simulated data of livestock populations.Results:Chip array(Chip)and four depths of GBS data was simulated.After quality control(call rate≥0.8 and MAF≥0.01),the remaining number of Chip and GBS SNPs were both approximately 7,000,averaged over 10 replicates.GBS genotypes were corrected with the proposed method.The reliability of genomic prediction was calculated using GBS,corrected GBS(GBSc),true genotypes for the GBS loci(GBSr)and Chip data.The results showed that GBSc had higher rates of correct genotype calls and higher correlations with true genotypes than GBS.For genomic prediction,using Chip data resulted in the highest reliability.As the depth increased to 10,the prediction reliabilities using GBS and GBSc data approached those using true GBS data.The reliabilities of genomic prediction using GBSc data were 0.604,0.672,0.684 and 0.704 after genomic correction,with the improved values of 0.013,0.009,0.006 and 0.001 at depth=2,4,5 and 10,respectively.Conclusions:The current study showed that a correction method for GBS data increased the genotype accuracies and,consequently,improved genomic predictions.These results suggest that a correction of GBS genotype is necessary,especially for the GBS data with low depths.
基金the National Key Research and Development Program of China(Grant No.2018YFB2200500)the National Natural Science Foundation(Grant Nos.62050073,62090054,61975196).
文摘Beta-gallium oxide(β-Ga_(2)O_(3))thin films were deposited on c-plane(0001)sapphire substrates with different mis-cut angles along<>by metal-organic chemical vapor deposition(MOCVD).The structural properties and surface morphology of as-grownβ-Ga_(2)O_(3)thin films were investigated in detail.It was found that by using thin buffer layer and mis-cut substrate technology,the full width at half maximum(FWHM)of the()diffraction peak of theβ-Ga_(2)O_(3)film is decreased from 2°on c-plane(0001)Al_(2)O_(3)substrate to 0.64°on an 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.The surface root-mean-square(RMS)roughness can also be improved greatly and the value is 1.27 nm for 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.Room temper-ature photoluminescence(PL)was observed,which was attributed to the self-trapped excitons formed by oxygen and gallium vacancies in the film.The ultraviolet-blue PL intensity related with oxygen and gallium vacancies is decreased with the increas-ing mis-cut angle,which is in agreement with the improved crystal quality measured by high resolution X-ray diffraction(HR-XRD).The present results provide a route for growing high qualityβ-Ga_(2)O_(3)film on Al_(2)O_(3)substrate.
基金support from the National Natural Science Foundation of China(Nos.52274404,U2032117,U22A20190)Natural Science Foundation of Hunan Province,China(No.2022JJ20065)+1 种基金the Science and Technology Innovation Program of Hunan Province,China(No.2022RC1001)the National Key Research and Development Program of China(No.2021YFB3400903).
文摘The improvement of post-form properties without compromising creep formability has been a critical issue in creep age forming of aluminum alloy component. A pretreatment process incorporating artificial pre-aging at 165 °C for 6 h/12 h/24 h followed by pre-strain(3%–9%)has been developed. This method not only evidently improves the strength but also accelerates the creep deformation during creep aging of an Al-Cu alloy. A strength increase of 50 MPa with a slight decrease of ductility relative to the 9% pre-strained alloy is acquired in the alloy artificially pre-aged for 24 h regardless of the pre-strain level(3%–9%). Artificial aging for 24 h prior to 3%pre-strain enables an increase of creep strain by 30%. The creep strain in the alloy artificially preaged for 24 h and pre-strained by 6% is comparable to that in the alloy pre-strained by 9%. The strength and ductility in the alloy artificially pre-aged for 6 h/12 h and pre-strained by 3% are even slightly higher than those in the alloy purely pre-strained by 9%. The characterizations by transmission electron microscopy reveal that pre-aging at 165 °C could promote the accumulation of dislocations during pre-straining due to the pinning effect of pre-existing Guinier-Preston zones(GP zones)/θ’’phases and thus expedite the creep deformation in respect to the pure pre-straining treatment. The enhanced precipitation of θ’phases at these pinned dislocations contributes to the improved strength after creep aging. The results demonstrate applying artificial pre-aging before pre-straining is an efficient strategy to elevate the creep aging response in Al alloys.
基金supported by the National Natural Science Foundation of China(Grant No.30800776)the State High-Tech Development Plan of China(Grant No.2008AA101002)the Recommend International Advanced Agricultural Science and Technology Plan of China(Grant No2011-G2A)
基金financially supported by the National Natural Science Foundation of China(Nos.52274404,52305441,and U22A20190)the Natural Science Foundation of Hunan province(Nos.2022JJ20065 and 2023JJ40739)+1 种基金the Science and Technology Innovation Program of Hunan Province(No.2022RC1001)the National Key R&D Program of China(No.2021YFB3400903).
文摘Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming.The stress-relaxation ageing(SRA)behavior and mechanical properties of a commercial 2219 aluminum alloy largely pre-deformed(LPD)by 80%have been systematically investigated.The stress relaxation ratio of the LPD alloy reaches approximately 94%regardless of the initial stress(50–350 MPa)after ageing for 12 h at 140°C.This relaxation ratio is about 2.9 and 1.8 times that in the T4 tempered alloy(27.6%under 50 MPa and 31.5%under 150 MPa)and T3 tempered alloy(37.6%under 50 MPa and 51.2%under 150 MPa),respectively.The microstructures,comprised of GP zones/θ'precipitates plus dislocation tangles,and tensile properties in the stress-relaxation-aged LPD alloys remain basically invariant with different initial stresses,as is vital importance for property consistency at different locations of the formed part.Under the same SRA condition,the LPD alloy has an increase of 150–230 MPa in yield strength relative to T3/T4 tempered alloy and obtains a uniform elongation of about 8%.A simple dislocation-based constitutive model accurately describing stress relaxation enhanced by the high dislocation density is established and embedded in the finite element package through a user subroutine.Simulations and experimental verifications show the LPD alloy sheet parts exhibit a nearly zero springback(<5%)after unloading in contrast to the springback larger than 65%in the T3/T4 alloy sheet parts under the same condition.Our findings demonstrate the high-dislocation-density-enhanced SRA response enables a high-performance springback-free age forming of Al alloy sheet.
基金supported in part by the National Key Research and Development Program of China(No.2018YFB2200500)the National Natural Science Foundation of China(No.62050073,62090054,and 61975196)the Key Research Program of Frontier Sciences,CAS(No.QYZDY-SSW-JSC022)。
文摘Heavy doped n-typeβ-G_(2)O_(3)(HD-G_(2)O_(3))was obtained by employing Si ion implantation technology on unintentionally dopedβ-G_(2)O_(3)single crystal substrates.To repair the G_(2)O_(3)lattice damage and activate the Si after implantation,the implanted substrates were annealed at 950℃,1000℃,and 1100℃,respectively.High-resolution X-ray diffraction and high-resolution transmission electron microscopy show that the ion-implanted layer has high lattice quality after high-temperature annealing at 1000℃.The minimum specific contact resistance is 9.2×10^(-5)Ω·cm^(2),which is attributed to the titanium oxide that is formed at the Ti/G_(2)O_(3)interface via rapid thermal annealing at 480℃.Based on these results,the lateralˇ-G_(2)O_(3)diodes were prepared,and the diodes exhibit high forward current density and low specific on-resistance.
