本研究探讨了Ruddlesden-Popper型双层锰酸盐LaSr_(2)Mn_(2)_(O6.96)作为全固态氟离子电池(FIBs)插层型正极材料的潜力。通过非原位X射线衍射分析了LaSr_(2)Mn_(2)_(O6.96)在氟离子嵌入/脱嵌过程中的结构变化,发现F-的嵌入会形成三种不...本研究探讨了Ruddlesden-Popper型双层锰酸盐LaSr_(2)Mn_(2)_(O6.96)作为全固态氟离子电池(FIBs)插层型正极材料的潜力。通过非原位X射线衍射分析了LaSr_(2)Mn_(2)_(O6.96)在氟离子嵌入/脱嵌过程中的结构变化,发现F-的嵌入会形成三种不同的四方相。为理解这些物相的复杂行为,采用X射线吸收光谱和磁学测量手段研究了Mn氧化态及配位环境的变化。在20 kN的堆叠压力和1 V至-1 V电位区间的电化学循环中,LaSr_(2)Mn_(2)_(O6.96)的比容量从初始的~30 mAh g^(-1)持续增加至200次循环后的~68 mAh g^(-1),库仑效率达~99%,且未出现容量衰减迹象。这表明双层锰酸盐LaSr_(2)Mn_(2)_(O6.96)有望成为循环稳定的全固态FIBs正极材料,尤其是在施加堆叠压力的条件下。展开更多
Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that c...Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that confer cold and UV resistance on the crop also facilitate human adaptation to high-altitude stresses.Specifically,β-glucans regulate blood glucose primarily via short-chain fatty acids(SCFAs)produced through gut microbiota fermentation,which directly mediate glucose homeostasis.Phenolamides accumulate via the phenylpropanoid pathway,with chalcone isomerase(CHI)serving as a key enzyme in flavonoid biosynthesis and enhancing UV-B resistance.Under low temperatures,β-glucans improve frost tolerance by modulating osmotic balance and inhibiting ice-nucleating proteins,while lipids maintain membrane fluidity to sustain cellular function during cold stress.Importantly,we explore the hypothesis that these same metabolites,upon consumption,may facilitate human adaptation to high-altitude stresses.This hypothesis is supported by preliminary epidemiological associations between Qingke consumption and favorable health outcomes in high-altitude populations,as well as established bioactivities of the implicated metabolites in vitro and in animal models.However,direct causal evidence in humans and a comprehensive understanding of the underlying molecular mechanisms remain key knowledge gaps that warrant future investigation.Qingke as a unique resource at the interface of agricultural resilience and human nutrition.Understanding its metabolic blueprint will inform the development of functional foods and climate-resilient crops.展开更多
光电振荡器是一种能够稳定产生自激振荡的微波光子共振系统,近年来得到了广泛的研究,工作频率达到数百GHz,相位噪声性能达到-163 dBc/Hz at 6 kHz,调谐范围达到数十千兆赫兹。文章回顾了光电振荡器问世以来的部分研究进展和重要应用,重...光电振荡器是一种能够稳定产生自激振荡的微波光子共振系统,近年来得到了广泛的研究,工作频率达到数百GHz,相位噪声性能达到-163 dBc/Hz at 6 kHz,调谐范围达到数十千兆赫兹。文章回顾了光电振荡器问世以来的部分研究进展和重要应用,重点介绍了近年来集成化光电振荡器的研究现状,并提出了一种可应用于集成化光电振荡器的新型电光晶体材料。展开更多
The textures and microstructures of hot-and cold-rolled sheets of an AA 5454 aluminium alloy were studied,with special attention paid to comparing the texture development for the symmetric and asymmetric cold rolling....The textures and microstructures of hot-and cold-rolled sheets of an AA 5454 aluminium alloy were studied,with special attention paid to comparing the texture development for the symmetric and asymmetric cold rolling.Scanning electron microscopy with electron-backscatter diffraction was used to monitor the development of the microstructure in the differently deformed and additionally annealed samples.Details of the formations and transformations of individual texture components occurring during the rolling processes were observed and discussed.The average grain sizes,textures and mechanical properties were correlated and explained for the symmetric and asymmetric cold-rolled samples.The asymmetric rolling is beneficial in terms of deep drawability because it reduces the planar anisotropy of the annealed material due to the decrease of the Cube,Goss,rotated-Cube and η-fibre texture components and at the same time strengthens X1-and X2-fibre texture components which are shear texture components and improve deep drawability.During the asymmetric cold rolling,the temperature increases due to friction,triggering recrystallisation processes and leading to larger grains.It is also confirmed that asymmetric cold rolling uses less rolling force and consequently less energy to produce a final material with better formability,particularly earing.展开更多
In a typical sintered multi-component Sm_(2)Co_(17)-type magnet with strong fiber texture,we show that the distributions of grain boundary precipitates(GBPs)are heavily dependent on the grain boundary(GB)geometry with...In a typical sintered multi-component Sm_(2)Co_(17)-type magnet with strong fiber texture,we show that the distributions of grain boundary precipitates(GBPs)are heavily dependent on the grain boundary(GB)geometry with respect to the texture direction,which has significant effects on domain wall pinning.Re-sults demonstrate that the continuous GBPs turn into discrete upon the angle between{0001}planes and GB increases from 0°to 90°,meanwhile the GBPs thickness and precipitation free zones(PFZs)width both increase linearly by a factor of 2.5-4.Transmission electron microscopy(TEM)reveals that the GBPs are alternatively stacked Cu-rich SmCo_(5)and Zr-rich Sm_(n+1)Co_(5n-1)(n=2,3,4)compounds,while the PFZs are composed of 2:17R and intermediate 2:17R’phases.Atomic-level elemental mappings and first-principles calculations indicate that Cu exists at the Co-2c site in the SmCo_(5)forming SmCo_(3)Cu_(2)and Zr locates at the dumbbell Sm-6c sites in the Sm_(n+1)Co_(5n-1).The symbiotic GBPs have orientation relationships of[0001]GBPs//[0001]2:17R and[1010]GBPs//[2110]2:17R.The formation of anisotropic GBPs is owing to the strong fiber texture,i.e.,the larger angle between{0001}planes and GBs,the more{0001}diffusion channels for atoms to GBs,resulting in discrete and thick GBPs.In-situ Lorentz TEM shows that the domain walls interrupted by GBPs migrate easily under applied magnetic fields.Possible approaches to enhance the magnetic hardness via tuning the GBs are proposed.展开更多
Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are ess...Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.展开更多
An active galactic nucleus(AGN)plays a crucial role in the evolution of its host galaxy,but the detailed mechanism remains ambiguous.The radiation from the AGN heats and ionizes the surrounding gas in the host galaxy,...An active galactic nucleus(AGN)plays a crucial role in the evolution of its host galaxy,but the detailed mechanism remains ambiguous.The radiation from the AGN heats and ionizes the surrounding gas in the host galaxy,creating a spatially extended narrow line region(NLR).Theoretically,the size of the NLR depends on the ionizing power of the AGN,making it a powerful tool to quantify the influence of the AGN on the host galaxy.To verify the relation between NLR and the central AGN,we collect a large sample of AGNs from the Mapping Nearby Galaxies at Apache Point Observatory,using the BPT diagnostic diagram of[OⅢ]λ5007/Hβand[NⅡ]λ6584/Hα.We have measured the sizes of NLRs with the surface brightness threshold of10^(-16)erg s^(-1)cm^(-2)arcsec^(-2),and find a log-linear relation between their sizes and[OⅢ]λ5007 luminosity with a slope of 0.470±0.025.This result is consistent with the predictions of the standard photoionization model.展开更多
Hydrodynamical cosmological simulations of galaxy formation such as IllustrisTNG or Auriga have shown considerable success in approximately matching many galaxy properties,but their treatment of the star-forming inter...Hydrodynamical cosmological simulations of galaxy formation such as IllustrisTNG or Auriga have shown considerable success in approximately matching many galaxy properties,but their treatment of the star-forming interstellar medium(ISM)has relied on heuristic sub-grid models.However,recent high-resolution simulations of the ISM that directly resolve the regulation of star formation suggest different mean relations for the dependences of pressure and star formation rate on the average gas density.In this study,we adopt such a modern,physically grounded parameterization inspired by the TIGRESS small-scale simulations.We dub this model TEQS and use it for a detailed comparative analysis of the formation and evolution of a Milky Way-sized galaxy when compared with the widely used TNG model.By employing high-resolution simulations in tall box setups,we first investigate the structural differences expected for these two models when applied to different self-gravitating gas surface densities.Our results indicate that TEQS produces considerably thinner gaseous layers and can be expected to form stellar distributions with smaller scale-height than TNG,especially at higher surface density.To test whether this induces systematic structural differences in cosmological galaxy formation simulations,we carry out zoom-in simulations of 12 galaxies taken from the set of Milky Way-sized galaxies that have been studied in the Auriga project.Comparing results for these galaxies shows that disk galaxies formed with the TEQS model have on average very similar stellar mass but are more concentrated in their central regions and exhibit smaller stellar radii compared to those formed with the TNG model.The differences in the scale-heights of the formed stellar disks are only marginal,however,suggesting that other factors for setting the thickness of the disk are more important than the applied ISM equation-of-state model.Overall,the predicted galaxy structure is quite similar for TNG and TEQS despite significant differences in the employed star formation law,demonstrating that feedback processes are more important in regulating the stellar mass than the precise star formation law itself.展开更多
文摘本研究探讨了Ruddlesden-Popper型双层锰酸盐LaSr_(2)Mn_(2)_(O6.96)作为全固态氟离子电池(FIBs)插层型正极材料的潜力。通过非原位X射线衍射分析了LaSr_(2)Mn_(2)_(O6.96)在氟离子嵌入/脱嵌过程中的结构变化,发现F-的嵌入会形成三种不同的四方相。为理解这些物相的复杂行为,采用X射线吸收光谱和磁学测量手段研究了Mn氧化态及配位环境的变化。在20 kN的堆叠压力和1 V至-1 V电位区间的电化学循环中,LaSr_(2)Mn_(2)_(O6.96)的比容量从初始的~30 mAh g^(-1)持续增加至200次循环后的~68 mAh g^(-1),库仑效率达~99%,且未出现容量衰减迹象。这表明双层锰酸盐LaSr_(2)Mn_(2)_(O6.96)有望成为循环稳定的全固态FIBs正极材料,尤其是在施加堆叠压力的条件下。
基金supported by the Financial Special Fund,grant number XZ202401JD0027National Barley Industry Technology System(CARS-05-01A-08)+3 种基金the Xizang Agri-Tech Innovation Project(XZNKY-2025-CXGC-T01)the Joint Funds of the National Natural Science Foundation of China(No.U20A2026)the Financial Special Fund,grant number(32401784,2017CZZX001/2,XZNKY-2018-C-021 and NYSTC202401)the China Agriculture Research System of Barley(CARS-05).
文摘Qingke,a staple crop grown on the high-altitude Tibetan Plateau,has evolved a metabolomic profile providing both environmental stress resilience and human nutrition.We review the hypothesis that the metabolites that confer cold and UV resistance on the crop also facilitate human adaptation to high-altitude stresses.Specifically,β-glucans regulate blood glucose primarily via short-chain fatty acids(SCFAs)produced through gut microbiota fermentation,which directly mediate glucose homeostasis.Phenolamides accumulate via the phenylpropanoid pathway,with chalcone isomerase(CHI)serving as a key enzyme in flavonoid biosynthesis and enhancing UV-B resistance.Under low temperatures,β-glucans improve frost tolerance by modulating osmotic balance and inhibiting ice-nucleating proteins,while lipids maintain membrane fluidity to sustain cellular function during cold stress.Importantly,we explore the hypothesis that these same metabolites,upon consumption,may facilitate human adaptation to high-altitude stresses.This hypothesis is supported by preliminary epidemiological associations between Qingke consumption and favorable health outcomes in high-altitude populations,as well as established bioactivities of the implicated metabolites in vitro and in animal models.However,direct causal evidence in humans and a comprehensive understanding of the underlying molecular mechanisms remain key knowledge gaps that warrant future investigation.Qingke as a unique resource at the interface of agricultural resilience and human nutrition.Understanding its metabolic blueprint will inform the development of functional foods and climate-resilient crops.
文摘光电振荡器是一种能够稳定产生自激振荡的微波光子共振系统,近年来得到了广泛的研究,工作频率达到数百GHz,相位噪声性能达到-163 dBc/Hz at 6 kHz,调谐范围达到数十千兆赫兹。文章回顾了光电振荡器问世以来的部分研究进展和重要应用,重点介绍了近年来集成化光电振荡器的研究现状,并提出了一种可应用于集成化光电振荡器的新型电光晶体材料。
文摘The textures and microstructures of hot-and cold-rolled sheets of an AA 5454 aluminium alloy were studied,with special attention paid to comparing the texture development for the symmetric and asymmetric cold rolling.Scanning electron microscopy with electron-backscatter diffraction was used to monitor the development of the microstructure in the differently deformed and additionally annealed samples.Details of the formations and transformations of individual texture components occurring during the rolling processes were observed and discussed.The average grain sizes,textures and mechanical properties were correlated and explained for the symmetric and asymmetric cold-rolled samples.The asymmetric rolling is beneficial in terms of deep drawability because it reduces the planar anisotropy of the annealed material due to the decrease of the Cube,Goss,rotated-Cube and η-fibre texture components and at the same time strengthens X1-and X2-fibre texture components which are shear texture components and improve deep drawability.During the asymmetric cold rolling,the temperature increases due to friction,triggering recrystallisation processes and leading to larger grains.It is also confirmed that asymmetric cold rolling uses less rolling force and consequently less energy to produce a final material with better formability,particularly earing.
基金the financial support by the National Nat-ural Science Foundation of China(No.52201032)the Science and Technology Innovation Program of Hunan Province(No.2023RC1013)+2 种基金supported by the Advanced Research Center(for FIB and Talos F200X usages)the State Key Laboratory of Powder Metallurgy(for Spectra 300 usage)the High Performance Computing Center(for supercomputing usage)of Central South University.
文摘In a typical sintered multi-component Sm_(2)Co_(17)-type magnet with strong fiber texture,we show that the distributions of grain boundary precipitates(GBPs)are heavily dependent on the grain boundary(GB)geometry with respect to the texture direction,which has significant effects on domain wall pinning.Re-sults demonstrate that the continuous GBPs turn into discrete upon the angle between{0001}planes and GB increases from 0°to 90°,meanwhile the GBPs thickness and precipitation free zones(PFZs)width both increase linearly by a factor of 2.5-4.Transmission electron microscopy(TEM)reveals that the GBPs are alternatively stacked Cu-rich SmCo_(5)and Zr-rich Sm_(n+1)Co_(5n-1)(n=2,3,4)compounds,while the PFZs are composed of 2:17R and intermediate 2:17R’phases.Atomic-level elemental mappings and first-principles calculations indicate that Cu exists at the Co-2c site in the SmCo_(5)forming SmCo_(3)Cu_(2)and Zr locates at the dumbbell Sm-6c sites in the Sm_(n+1)Co_(5n-1).The symbiotic GBPs have orientation relationships of[0001]GBPs//[0001]2:17R and[1010]GBPs//[2110]2:17R.The formation of anisotropic GBPs is owing to the strong fiber texture,i.e.,the larger angle between{0001}planes and GBs,the more{0001}diffusion channels for atoms to GBs,resulting in discrete and thick GBPs.In-situ Lorentz TEM shows that the domain walls interrupted by GBPs migrate easily under applied magnetic fields.Possible approaches to enhance the magnetic hardness via tuning the GBs are proposed.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406000 and 2022YFA1403800)the National Natural Science Foundation of China(Grant Nos.12474002,22171283,22203031,12434005,12204515,and 12074175)support of the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)。
文摘Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.12192222,12192220 and 12121003)。
文摘An active galactic nucleus(AGN)plays a crucial role in the evolution of its host galaxy,but the detailed mechanism remains ambiguous.The radiation from the AGN heats and ionizes the surrounding gas in the host galaxy,creating a spatially extended narrow line region(NLR).Theoretically,the size of the NLR depends on the ionizing power of the AGN,making it a powerful tool to quantify the influence of the AGN on the host galaxy.To verify the relation between NLR and the central AGN,we collect a large sample of AGNs from the Mapping Nearby Galaxies at Apache Point Observatory,using the BPT diagnostic diagram of[OⅢ]λ5007/Hβand[NⅡ]λ6584/Hα.We have measured the sizes of NLRs with the surface brightness threshold of10^(-16)erg s^(-1)cm^(-2)arcsec^(-2),and find a log-linear relation between their sizes and[OⅢ]λ5007 luminosity with a slope of 0.470±0.025.This result is consistent with the predictions of the standard photoionization model.
基金supported by the National SKA Program of China(grant No.2020SKA0110100)the CAS Project for Young Scientists in Basic Research (No.YSBR-092)the science research grants from the China Manned Space Project with Nos.CMS-CSST-2021-A02 and GHfund C(202407031909)
文摘Hydrodynamical cosmological simulations of galaxy formation such as IllustrisTNG or Auriga have shown considerable success in approximately matching many galaxy properties,but their treatment of the star-forming interstellar medium(ISM)has relied on heuristic sub-grid models.However,recent high-resolution simulations of the ISM that directly resolve the regulation of star formation suggest different mean relations for the dependences of pressure and star formation rate on the average gas density.In this study,we adopt such a modern,physically grounded parameterization inspired by the TIGRESS small-scale simulations.We dub this model TEQS and use it for a detailed comparative analysis of the formation and evolution of a Milky Way-sized galaxy when compared with the widely used TNG model.By employing high-resolution simulations in tall box setups,we first investigate the structural differences expected for these two models when applied to different self-gravitating gas surface densities.Our results indicate that TEQS produces considerably thinner gaseous layers and can be expected to form stellar distributions with smaller scale-height than TNG,especially at higher surface density.To test whether this induces systematic structural differences in cosmological galaxy formation simulations,we carry out zoom-in simulations of 12 galaxies taken from the set of Milky Way-sized galaxies that have been studied in the Auriga project.Comparing results for these galaxies shows that disk galaxies formed with the TEQS model have on average very similar stellar mass but are more concentrated in their central regions and exhibit smaller stellar radii compared to those formed with the TNG model.The differences in the scale-heights of the formed stellar disks are only marginal,however,suggesting that other factors for setting the thickness of the disk are more important than the applied ISM equation-of-state model.Overall,the predicted galaxy structure is quite similar for TNG and TEQS despite significant differences in the employed star formation law,demonstrating that feedback processes are more important in regulating the stellar mass than the precise star formation law itself.
