We investigate the relationships between infrared excess(IRX = LIR/LUV) and Balmer decrement(Hα/Hβ) as indicators of dust attenuation for 609 H II regions at scales of ~50–200 pc in NGC 628, utilizing data from Ast...We investigate the relationships between infrared excess(IRX = LIR/LUV) and Balmer decrement(Hα/Hβ) as indicators of dust attenuation for 609 H II regions at scales of ~50–200 pc in NGC 628, utilizing data from AstroSat, the James Webb Space Telescope(JWST) and Multi Unit Spectroscopic Explorer. Our findings indicate that about three-fifths of the sample H II regions reside within the regime occupied by local star-forming galaxies(SFGs) along the dust attenuation correlation described by their corresponding color excess parameters E(B-V)IRX= 0.51 E(B-V)Hα/Hβ. Nearly 27% of the sample exhibits E(B-V)IRX> E(B-V)Hα/Hβ, while a small fraction(~13%) displays significantly lower E(B-V)IRXcompared to E(B-V)Hα/Hβ. These results suggest that the correlation between the two dust attenuation indicators no longer holds for spatially resolved H II regions. Furthermore, the ratio of E(B-V)IRXto E(B-V)Hα/Hβremains unaffected by various physical parameters of the H II regions, including star formation rate(SFR), SFR surface density, infrared luminosity(LIR),LIRsurface density, stellar mass, gas-phase metallicity, circularized radius, and the distance to the galactic center.We argue that the ratio is primarily influenced by the evolution of the surrounding interstellar medium of the starforming regions, transitioning from an early dense and thick phase to the late blown-away stage.展开更多
We study the local atomic structure evolution of UZr and UZr_(2) alloy melts upon solidification through ab initio molecular dynamics simulations.This is achieved by analyzing in detail the temperature dependence of s...We study the local atomic structure evolution of UZr and UZr_(2) alloy melts upon solidification through ab initio molecular dynamics simulations.This is achieved by analyzing in detail the temperature dependence of structure factors,pair correlation functions,the bond angle distributions,Honeycutt-Anderson index and Voronoi tessellation analysis as well as local bond orientation order parameters.We observe that as the temperature decreases the pair correlation functions and structure factors become more structured with clear distinctions at the liquid–solid phase transition temperature.The Honeycutt-Anderson indices and Voronoi tessellation analysis indicate that the liquid phase is predominantly comprised of the icosahedra-like local structures,whose fraction increases with decreasing temperature up to the transition temperature and then abruptly drops at the transition temperature,whereas the bcc-like local atomic structures dominate during the solidification process.Furthermore,the bond orientation order analyses with\({\overline{w}}_{6}\)–\({\overline{q}}_{6}\)correlation map and bond angle distribution imply that the local structures mainly consist of the bcc-type during the solidification below the transition temperature.All the analyses are consistent with each other,showing a first-order liquid to solid phase transition for both UZr and UZr_(2) solid solutions,which only differ in different predicted transition temperatures.This work provides a comprehensive insight into the detailed local structure evolution during the solidification of the U–Zr alloy melts at the atomic level.Similar strategies used here can be extended to studying the liquid–solid phase transition in other alloy systems.展开更多
The isothermal oxidation behavior of Fe-10 Al,Fe-15 Al,Fe-20 Al alloys with and without the addition of0.1 at% Y was studied at 800℃ under 1×105 Pa of flowing pure O2 for 24 h.The oxidation of three Fe-Al alloys...The isothermal oxidation behavior of Fe-10 Al,Fe-15 Al,Fe-20 Al alloys with and without the addition of0.1 at% Y was studied at 800℃ under 1×105 Pa of flowing pure O2 for 24 h.The oxidation of three Fe-Al alloys can be divided into transient state and steady state oxidation stages.The oxidation of each stage is approximately in accordance with the parabolic law.The addition of 0.1 at% Y changes the oxidation behavior obviously and leads to a significant increase of the weight gain of Fe-10 Al and Fe-15 Al.The scale grown on Fe-10 Al is much thicker and more complicated than that grown on Fe-20 Al,which is composed of an exclusive thin layer of Al2 O3 protective film.Due to the formation of a large number of nodules,the scales grown on Fe-15 AI cannot provide full protection for the alloy.Scale micro structure of the three Fe-Al-0.1 Y alloys is similar to their corresponding Fe-Al alloys.However,nodules with very small size still appear on the surface of Fe-20 Al-0.1 Y alloy.The critical Al concentration to form an exclusive Al2 O3 protective layer for Fe-Al binary alloy is on the borderline between 15 at%-20 at%.For Fe-Al-0.1 Y alloy,the presence of 20 at% Al is not enough to inhibit the growth of nodules.展开更多
Nickel-based single crystal superalloys have been widely used in aero-engines and gas turbine engines.To improve the creep resistance,rhenium is often added to the alloys.However,it is not yet fully under-stood how th...Nickel-based single crystal superalloys have been widely used in aero-engines and gas turbine engines.To improve the creep resistance,rhenium is often added to the alloys.However,it is not yet fully under-stood how the added Re elements distribute in the alloys and how the microstructure evolves with the addition of Re.Here,we performed extensive first-principles calculations based Monte-Carlo simulated annealing of Ni-Al-Re ternary alloys with different Re concentrations ranging from 0.5 at.%to 6.0 at.%.The results demonstrate that with the decreasing temperature,most of Re atoms stay in theγphase,while a few of Re atoms stay in theγ'phase and tend to occupy the Al positions.At low temperatures,the Re atoms segregate at theγ/γ'boundary,in good agreement with experiment.We find that the disorder-order transition temperature of the Ni-Al-Re ternary alloys increases with the Re concentration due to the Re-enhanced Al-Al ordering tendency.In addition,we observe that at low temperatures the Re segregation at theγ/γ'boundary promotes the formation of Ni 4 Re-or Ni 8 Re-like local structures as the Re concentration is over 2 at.%.The formation of a large amount of these local structures consumes the Re atoms in solid solutions,and thus from the solid-solution strengthening point of view,this would have a negative influence on the creep resistance of the superalloys.This work provides important atomistic insights on the Re distribution and its effects on the stability of superalloys.展开更多
Autism spectrum disorder(ASD)affects 1-2%of all children and poses a great social and economic challenge for the globe.As a highly heterogeneous neurodevelopmental disorder,the development of its treatment is extremel...Autism spectrum disorder(ASD)affects 1-2%of all children and poses a great social and economic challenge for the globe.As a highly heterogeneous neurodevelopmental disorder,the development of its treatment is extremely challenging.Multiple pathways have been linked to the pathogenesis of ASD,including signaling involved in synaptic function,oxytocinergic activities,immune homeostasis,chromatin modifications,and mitochondrial functions.Here,we identify secretagogin(SCGN),a regulator of synaptic transmission,as a new risk gene for ASD.Two heterozygous loss-of-function mutations in SCGN are presented in ASD probands.Deletion of Scgn in zebrafish or mice leads to autism-like behaviors and impairs brain development.Mechanistically,Scgn deficiency disrupts the oxytocin signaling and abnormally activates inflammation in both animal models.Both ASD probands carrying Scgn mutations also show reduced oxytocin levels.Importantly,we demonstrate that the administration of oxytocin and anti-inflammatory drugs can attenuate ASD-associated defects caused by SCGN deficiency.Altogether,we identify a convergence between a potential autism genetic risk factor SCGN,and the pathological deregulation in oxytocinergic signaling and immune responses,providing potential treatment for ASD patients suffering from SCGN deficiency.Our study also indicates that it is critical to identify and stratify ASD patient populations based on their disease mechanisms,which could greatly enhance therapeutic success.展开更多
基金supported by the National Key Research and Development Program of China (2023YFA1608100)the National Science Foundation of China (NSFC, Grant Nos.12233005, 12073078, 12173088, and 12303015)+3 种基金the China Manned Space Program with grants nos. CMS-CSST-2025-A20 and CMS-CSST-2025-A08the support from the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology(2024yjrc104)the National Science Foundation of Jiangsu Province (BK20231106)the science research grants from the China Manned Space Project
文摘We investigate the relationships between infrared excess(IRX = LIR/LUV) and Balmer decrement(Hα/Hβ) as indicators of dust attenuation for 609 H II regions at scales of ~50–200 pc in NGC 628, utilizing data from AstroSat, the James Webb Space Telescope(JWST) and Multi Unit Spectroscopic Explorer. Our findings indicate that about three-fifths of the sample H II regions reside within the regime occupied by local star-forming galaxies(SFGs) along the dust attenuation correlation described by their corresponding color excess parameters E(B-V)IRX= 0.51 E(B-V)Hα/Hβ. Nearly 27% of the sample exhibits E(B-V)IRX> E(B-V)Hα/Hβ, while a small fraction(~13%) displays significantly lower E(B-V)IRXcompared to E(B-V)Hα/Hβ. These results suggest that the correlation between the two dust attenuation indicators no longer holds for spatially resolved H II regions. Furthermore, the ratio of E(B-V)IRXto E(B-V)Hα/Hβremains unaffected by various physical parameters of the H II regions, including star formation rate(SFR), SFR surface density, infrared luminosity(LIR),LIRsurface density, stellar mass, gas-phase metallicity, circularized radius, and the distance to the galactic center.We argue that the ratio is primarily influenced by the evolution of the surrounding interstellar medium of the starforming regions, transitioning from an early dense and thick phase to the late blown-away stage.
基金This work was supported by the National Science Fund for Distinguished Young Scholars(No.51725103)the Rare and Precious Metals Material Genetic Engineering Project of Yunnan Province(No.202002AB080001-1)the National Natural Science Foundation of China(Grant No.52188101).All calculations have been performed on the high-performance computational cluster in the Shenyang National University Science and Technology Park.
文摘We study the local atomic structure evolution of UZr and UZr_(2) alloy melts upon solidification through ab initio molecular dynamics simulations.This is achieved by analyzing in detail the temperature dependence of structure factors,pair correlation functions,the bond angle distributions,Honeycutt-Anderson index and Voronoi tessellation analysis as well as local bond orientation order parameters.We observe that as the temperature decreases the pair correlation functions and structure factors become more structured with clear distinctions at the liquid–solid phase transition temperature.The Honeycutt-Anderson indices and Voronoi tessellation analysis indicate that the liquid phase is predominantly comprised of the icosahedra-like local structures,whose fraction increases with decreasing temperature up to the transition temperature and then abruptly drops at the transition temperature,whereas the bcc-like local atomic structures dominate during the solidification process.Furthermore,the bond orientation order analyses with\({\overline{w}}_{6}\)–\({\overline{q}}_{6}\)correlation map and bond angle distribution imply that the local structures mainly consist of the bcc-type during the solidification below the transition temperature.All the analyses are consistent with each other,showing a first-order liquid to solid phase transition for both UZr and UZr_(2) solid solutions,which only differ in different predicted transition temperatures.This work provides a comprehensive insight into the detailed local structure evolution during the solidification of the U–Zr alloy melts at the atomic level.Similar strategies used here can be extended to studying the liquid–solid phase transition in other alloy systems.
基金Project supported by the National Natural Science Foundation of China (51701054)the Science and Technology Research Program of Jiangxi Provincial Education Department of China (GJJ160770)。
文摘The isothermal oxidation behavior of Fe-10 Al,Fe-15 Al,Fe-20 Al alloys with and without the addition of0.1 at% Y was studied at 800℃ under 1×105 Pa of flowing pure O2 for 24 h.The oxidation of three Fe-Al alloys can be divided into transient state and steady state oxidation stages.The oxidation of each stage is approximately in accordance with the parabolic law.The addition of 0.1 at% Y changes the oxidation behavior obviously and leads to a significant increase of the weight gain of Fe-10 Al and Fe-15 Al.The scale grown on Fe-10 Al is much thicker and more complicated than that grown on Fe-20 Al,which is composed of an exclusive thin layer of Al2 O3 protective film.Due to the formation of a large number of nodules,the scales grown on Fe-15 AI cannot provide full protection for the alloy.Scale micro structure of the three Fe-Al-0.1 Y alloys is similar to their corresponding Fe-Al alloys.However,nodules with very small size still appear on the surface of Fe-20 Al-0.1 Y alloy.The critical Al concentration to form an exclusive Al2 O3 protective layer for Fe-Al binary alloy is on the borderline between 15 at%-20 at%.For Fe-Al-0.1 Y alloy,the presence of 20 at% Al is not enough to inhibit the growth of nodules.
基金financially supported by the National Science Fund for Distinguished Young Scholars (No.51725103)the National Key R&D Program of China (No.2021YFB3501503)+1 种基金the Funding of National Science and Technology Major Project (Nos.J2019-VI-0004-0118,J2019-VI-0019-0134)the Project funded by China Postdoctoral Science Foundation (No.2021M700153).
文摘Nickel-based single crystal superalloys have been widely used in aero-engines and gas turbine engines.To improve the creep resistance,rhenium is often added to the alloys.However,it is not yet fully under-stood how the added Re elements distribute in the alloys and how the microstructure evolves with the addition of Re.Here,we performed extensive first-principles calculations based Monte-Carlo simulated annealing of Ni-Al-Re ternary alloys with different Re concentrations ranging from 0.5 at.%to 6.0 at.%.The results demonstrate that with the decreasing temperature,most of Re atoms stay in theγphase,while a few of Re atoms stay in theγ'phase and tend to occupy the Al positions.At low temperatures,the Re atoms segregate at theγ/γ'boundary,in good agreement with experiment.We find that the disorder-order transition temperature of the Ni-Al-Re ternary alloys increases with the Re concentration due to the Re-enhanced Al-Al ordering tendency.In addition,we observe that at low temperatures the Re segregation at theγ/γ'boundary promotes the formation of Ni 4 Re-or Ni 8 Re-like local structures as the Re concentration is over 2 at.%.The formation of a large amount of these local structures consumes the Re atoms in solid solutions,and thus from the solid-solution strengthening point of view,this would have a negative influence on the creep resistance of the superalloys.This work provides important atomistic insights on the Re distribution and its effects on the stability of superalloys.
基金We thank Drs.Wentong Meng and Qiaorong Huang(Laboratory of Stem Cell Biology,West China Hospital,Sichuan University)for assistance with experimental technology.Research in the authors’laboratory is supported by National Key Research and Development Program of China(2022YFA1100056,2018YFC1005004)Natural Science Foundation of China(NSFC)grants(#92254302,#31871429)+2 种基金National Science Fund for Distinguished Young Scholars(#32125012)1.3.5 project for disciplines of excellence,West China Hospital,Sichuan University(ZYGD20007 and ZYJC18011 to X.M.)Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJQN20210436).
文摘Autism spectrum disorder(ASD)affects 1-2%of all children and poses a great social and economic challenge for the globe.As a highly heterogeneous neurodevelopmental disorder,the development of its treatment is extremely challenging.Multiple pathways have been linked to the pathogenesis of ASD,including signaling involved in synaptic function,oxytocinergic activities,immune homeostasis,chromatin modifications,and mitochondrial functions.Here,we identify secretagogin(SCGN),a regulator of synaptic transmission,as a new risk gene for ASD.Two heterozygous loss-of-function mutations in SCGN are presented in ASD probands.Deletion of Scgn in zebrafish or mice leads to autism-like behaviors and impairs brain development.Mechanistically,Scgn deficiency disrupts the oxytocin signaling and abnormally activates inflammation in both animal models.Both ASD probands carrying Scgn mutations also show reduced oxytocin levels.Importantly,we demonstrate that the administration of oxytocin and anti-inflammatory drugs can attenuate ASD-associated defects caused by SCGN deficiency.Altogether,we identify a convergence between a potential autism genetic risk factor SCGN,and the pathological deregulation in oxytocinergic signaling and immune responses,providing potential treatment for ASD patients suffering from SCGN deficiency.Our study also indicates that it is critical to identify and stratify ASD patient populations based on their disease mechanisms,which could greatly enhance therapeutic success.
