Both solute-segregated long-period stacking ordered(LPSO)structure and stacking faults(SFs)are essential in strengthening rare-earth(RE)Mg alloys.Herein,LPSO-enriched Mg and SFs-enriched Mg are fabricated and comparab...Both solute-segregated long-period stacking ordered(LPSO)structure and stacking faults(SFs)are essential in strengthening rare-earth(RE)Mg alloys.Herein,LPSO-enriched Mg and SFs-enriched Mg are fabricated and comparably investigated for fatigue performances.During fatigue,the Mg nanolayers between LPSO lamellae or SFs act as the gliding channels of dislocations.However,SFs-enriched Mg exhibits outstanding fatigue strength due to solute strengthening within Mg nanolayers.Solute strengthening is assumed to contribute to the local accumulation of basal dislocations and the activation of non-basal dislocations.Dislocations are restricted locally and cannot glide long distances to specimen surfaces,which mitigates fatigue-induced extrusions and slip markings,ultimately leading to an increase in fatigue strength.These findings guide the development of RE-Mg alloys towards a synergy between high tensile and high fatigue performances.展开更多
Ultrasonic fatigue tests are performed on a magnesium alloy with and without ultrasonic peening treatment(UPT).Surface enhancement layer leads to the complete change of crack initiation sites.However,crack initiation ...Ultrasonic fatigue tests are performed on a magnesium alloy with and without ultrasonic peening treatment(UPT).Surface enhancement layer leads to the complete change of crack initiation sites.However,crack initiation mechanism keeps the same and results in a single-faceted morphology at crack initiation site.Microcracks initiate as Mode Ⅱ crack within the original grain,but deflect to Mode I crack outside of the original cracked grain.A threshold SIF value is proposed to evaluate the retarding effect of grain boundary on microcrack propagation.Outside of the original cracked grain,Mode I crack propagation below the threshold ΔK_(σ-th) is responsible for the formation of fine granular area(FGA,a nano-grain layer).Based on the Numerous Cyclic Pressing(NCP) model,it is proposed that crack type should be another necessary condition for the formation of FGA.展开更多
Welded structures in aero-engines commonly operate in high-temperature environments,making them susceptible to reduced fatigue life and premature failure due to welding defects within the structure.Thus,the gigacycle ...Welded structures in aero-engines commonly operate in high-temperature environments,making them susceptible to reduced fatigue life and premature failure due to welding defects within the structure.Thus,the gigacycle fatigue behaviors of titanium alloy welded joints at both room temperature(RT)and 400 ℃ were investigated,aiming to uncover the mechanism behind the formation of fine granular area(FGA)surrounding welded pores.The research findings demonstrate that the S-N curves of TC17 tita-nium alloy electron beam welded joint undergo a transition from a single linear decline at RT to a bilin-ear decline at 400 ℃.However,the fatigue failure mode remains unaffected by temperatures,and crack initiation is attributed to welded pores.By utilizing the Chapetti model curve to modify the Kitagawa-Takahashi(K-T)diagram,the lower threshold stress amplitude is introduced,enabling the determination of a safe size for welded pores at 400 ℃,which is calculated to be 11.3 μm.Additionally,the Gumbel probability distribution function is employed to assess the maximum size of welded pores.Finally,based on dislocation interactions,the formation mechanism of the FGA consisting of discontinuous nanograins with high-density dislocations is elucidated.展开更多
The composite photoanodes composed by cobalt phosphate catalyst(Co-Pi) modified semiconductor have been widely used for solar water splitting,but the improvement mechanism has not been experimentally confirmed.Here we...The composite photoanodes composed by cobalt phosphate catalyst(Co-Pi) modified semiconductor have been widely used for solar water splitting,but the improvement mechanism has not been experimentally confirmed.Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co-Pi catalyst on hematite nanowire photoanode.It is found that under illumination the Co-Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co-Pi layer by increasing the electrical conductivity of the composite structure under a low potential.The Co-Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential.These results provide important new understanding of the performance improvement mechanism for the Co-Pi-modified semiconductor nanowire composite photoanodes.展开更多
Primary open-angle glaucoma(POAG),a leading cause of irreversible blindness,involves complex neurodegeneration in which the contribution of systemic immunity remains enigmatic.Here,we dissect the circulating immune la...Primary open-angle glaucoma(POAG),a leading cause of irreversible blindness,involves complex neurodegeneration in which the contribution of systemic immunity remains enigmatic.Here,we dissect the circulating immune landscape in POAG patients via high-resolution single-cell RNA sequencing of~1.4 million peripheral blood mononuclear cells(PBMCs)from 110 patients and 110 controls of Chinese ancestry.We revealed significant immune remodeling in POAG,characterized by increased CD4+T lymphocytes and myeloid cells and impaired cytolytic potential,as evidenced by reduced cell proportions of terminally differentiated CD8+GZMK+T cells and NK cells.Transcriptomic analysis revealed a sophisticated dual transcriptional landscape in which both proinflammatory and neuroprotective signaling pathways coexist across multiple immune cell lineages.While TNF and IFNG pathway genes were broadly downregulated,specific inflammatory activation components and neuroprotective genes were upregulated in distinct cell populations,suggesting that POAG represents a complex immunometabolic syndrome characterized by a dysregulated balance between inflammatory and neuroprotective signaling.Cell type-specific eQTL mapping and SMR analysis revealed that POAG genetic risk loci exert their effects through immune gene regulation in specific PBMC subsets.Functional validation using Ifng-/-and Tnf+/-mice in an LPS/NMDA-induced retinal injury model,which mirrored the immune alterations observed in human POAG,demonstrated that genetic deficiency in these pathways markedly exacerbated retinal ganglion cell loss and visual pathway deficits.Our study establishes a crucial link between systemic immune dysregulation-specifically the disrupted balance between inflammatory and neuroprotective signaling-and retinal health,highlighting the importance of restoring this balance for future POAG therapeutic strategies.展开更多
基金supported by National Natural Science Foundation of China(Nos.12102280,12172238,12332012)Postdoctoral Fellowship Program of CPSF(No.GZB20230473)+1 种基金Support of Ultramicroscopy Research Center(URC,Kyushu University)are highly acknowledged.Yao Chen acknowledges the support of JSPS Fellowship(No.JP22F22720)JSPS KAKENHI(No JP22K03828).
文摘Both solute-segregated long-period stacking ordered(LPSO)structure and stacking faults(SFs)are essential in strengthening rare-earth(RE)Mg alloys.Herein,LPSO-enriched Mg and SFs-enriched Mg are fabricated and comparably investigated for fatigue performances.During fatigue,the Mg nanolayers between LPSO lamellae or SFs act as the gliding channels of dislocations.However,SFs-enriched Mg exhibits outstanding fatigue strength due to solute strengthening within Mg nanolayers.Solute strengthening is assumed to contribute to the local accumulation of basal dislocations and the activation of non-basal dislocations.Dislocations are restricted locally and cannot glide long distances to specimen surfaces,which mitigates fatigue-induced extrusions and slip markings,ultimately leading to an increase in fatigue strength.These findings guide the development of RE-Mg alloys towards a synergy between high tensile and high fatigue performances.
基金supported by the National Natural Science Foundation of China (Nos. 12102280, 12172238, 11832007, 12022208, 12072212, and 52003181)the Science & Technology Support Program of Sichuan Province (Nos. 2020YJ0230, and 2021YJ0555)the Fundamental Research Funds for the Central Universities of China (No.2021SCU12129)
文摘Ultrasonic fatigue tests are performed on a magnesium alloy with and without ultrasonic peening treatment(UPT).Surface enhancement layer leads to the complete change of crack initiation sites.However,crack initiation mechanism keeps the same and results in a single-faceted morphology at crack initiation site.Microcracks initiate as Mode Ⅱ crack within the original grain,but deflect to Mode I crack outside of the original cracked grain.A threshold SIF value is proposed to evaluate the retarding effect of grain boundary on microcrack propagation.Outside of the original cracked grain,Mode I crack propagation below the threshold ΔK_(σ-th) is responsible for the formation of fine granular area(FGA,a nano-grain layer).Based on the Numerous Cyclic Pressing(NCP) model,it is proposed that crack type should be another necessary condition for the formation of FGA.
基金National Natural Science Foundation of China(Nos.12172238,11832007,12022208,and 12102280)Fundamental Research Funds for the Central Universities of Sichuan University(No.CJ202207)Sichuan Province Science and Technology Project(No.2022JDJQ0011).
文摘Welded structures in aero-engines commonly operate in high-temperature environments,making them susceptible to reduced fatigue life and premature failure due to welding defects within the structure.Thus,the gigacycle fatigue behaviors of titanium alloy welded joints at both room temperature(RT)and 400 ℃ were investigated,aiming to uncover the mechanism behind the formation of fine granular area(FGA)surrounding welded pores.The research findings demonstrate that the S-N curves of TC17 tita-nium alloy electron beam welded joint undergo a transition from a single linear decline at RT to a bilin-ear decline at 400 ℃.However,the fatigue failure mode remains unaffected by temperatures,and crack initiation is attributed to welded pores.By utilizing the Chapetti model curve to modify the Kitagawa-Takahashi(K-T)diagram,the lower threshold stress amplitude is introduced,enabling the determination of a safe size for welded pores at 400 ℃,which is calculated to be 11.3 μm.Additionally,the Gumbel probability distribution function is employed to assess the maximum size of welded pores.Finally,based on dislocation interactions,the formation mechanism of the FGA consisting of discontinuous nanograins with high-density dislocations is elucidated.
基金financially supported by the National Natural Science Foundation of China (No.21503109)the Research-Starting Funds for Introduced Talents of Nanjing Tech University。
文摘The composite photoanodes composed by cobalt phosphate catalyst(Co-Pi) modified semiconductor have been widely used for solar water splitting,but the improvement mechanism has not been experimentally confirmed.Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co-Pi catalyst on hematite nanowire photoanode.It is found that under illumination the Co-Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co-Pi layer by increasing the electrical conductivity of the composite structure under a low potential.The Co-Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential.These results provide important new understanding of the performance improvement mechanism for the Co-Pi-modified semiconductor nanowire composite photoanodes.
基金supported by the National Natural Science Foundation of China(82271105,82571240,81970839)the Sichuan Science and Technology Program(2023ZYD0059 and 2021YFS0033).
文摘Primary open-angle glaucoma(POAG),a leading cause of irreversible blindness,involves complex neurodegeneration in which the contribution of systemic immunity remains enigmatic.Here,we dissect the circulating immune landscape in POAG patients via high-resolution single-cell RNA sequencing of~1.4 million peripheral blood mononuclear cells(PBMCs)from 110 patients and 110 controls of Chinese ancestry.We revealed significant immune remodeling in POAG,characterized by increased CD4+T lymphocytes and myeloid cells and impaired cytolytic potential,as evidenced by reduced cell proportions of terminally differentiated CD8+GZMK+T cells and NK cells.Transcriptomic analysis revealed a sophisticated dual transcriptional landscape in which both proinflammatory and neuroprotective signaling pathways coexist across multiple immune cell lineages.While TNF and IFNG pathway genes were broadly downregulated,specific inflammatory activation components and neuroprotective genes were upregulated in distinct cell populations,suggesting that POAG represents a complex immunometabolic syndrome characterized by a dysregulated balance between inflammatory and neuroprotective signaling.Cell type-specific eQTL mapping and SMR analysis revealed that POAG genetic risk loci exert their effects through immune gene regulation in specific PBMC subsets.Functional validation using Ifng-/-and Tnf+/-mice in an LPS/NMDA-induced retinal injury model,which mirrored the immune alterations observed in human POAG,demonstrated that genetic deficiency in these pathways markedly exacerbated retinal ganglion cell loss and visual pathway deficits.Our study establishes a crucial link between systemic immune dysregulation-specifically the disrupted balance between inflammatory and neuroprotective signaling-and retinal health,highlighting the importance of restoring this balance for future POAG therapeutic strategies.
