Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not bee...Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments.展开更多
Wire arc additive manufacturing(WAAM)technique is a promising approach to producing large-scale metal components due to high deposition efficiency and low production cost.However,fundamental research about WAAM-proces...Wire arc additive manufacturing(WAAM)technique is a promising approach to producing large-scale metal components due to high deposition efficiency and low production cost.However,fundamental research about WAAM-processed Al-Mg-Sc-Zr alloy was still fewer.In this study,Al-6.54Mg-0.36Sc-0.11Zr(wt%)components were successfully manufactured by WAAM with an interlayer temperature at 100℃(named IW)and continuous printing(named CP),and the corresponding porosity,microstructure,and mechanical properties of components were studied in detail.The porosity of components as-deposited was relatively low,about 0.385%and 0.116%,respectively.The microstructures of the two components exhibited the same distribution characteristics in XZ and YZ planes:fine equiaxed grains(FEG)at remelted zone+FEG and coarse equiaxed grain(CEG)alternative distribution at middle zone+FEG at the top zone of the molten pool.The average grain size of component IW was about 10.51±6.01μm,and that of component CP significantly increased,to about 11.85±5.86μm.The short-circuit transition mode of cold metal transfer technology and the heterogeneous nucleation effect of primary Al3(Sc,Zr)and Al3(Sc,Zr,Ti)phases together promoted the formation of equiaxed grains and refined the microstructures.After heat treatment at 325℃and 6 h,nano-Al3Sc precipitated with a size of about 15-50 nm.The yield strength(YS)of components IW and CP increased from 171±3 to 261±1 MPa and 168±7 to 240±17 MPa,respectively.Component IW had the highest ultimate tensile strength,about 400±1 MPa.For WAAMprocessed Al-Mg-Sc-Zr alloys,the contribution of the strengthening mechanism to YS was solid solution strengthening>precipitation strengthening>fine grain strengthening>dislocation strengthening.展开更多
High-precision magnetic field measurements are crucial for understanding Earth’s internal structure,space environment,and dynamic geomagnetic variations.Data from the Fluxgate Magnetometer (FGM) on the Macao Science ...High-precision magnetic field measurements are crucial for understanding Earth’s internal structure,space environment,and dynamic geomagnetic variations.Data from the Fluxgate Magnetometer (FGM) on the Macao Science Satellite-1A (MSS-1A),added to data from other space-based magnetometers,should increase significantly the ability of scientists to observe changes in Earth’s magnetic field over time and space.Additionally,the MSS-1A’s FGM is intended to help identify magnetic disturbances affecting the spacecraft itself.This report focuses on the in-flight calibration of the MSS-1 FGM.A scalar calibration,independent of geomagnetic field models,was performed to correct offsets,sensitivities,and misalignment angles of the FGM.Using seven months of data,we find that the in-flight calibration parameters show good stability.We determined Euler angles describing the rotational relationship between the FGM and the Advanced Stellar Compass (ASC) coordinate system using two approaches:calibration with the CHAOS-7 geomagnetic field model,and simultaneous estimation of Euler angles and Gaussian spherical harmonic coefficients through self-consistent modeling.The accuracy of Euler angles describing the rotation was better than 18 arcsec.The calibrated FGM data exhibit good agreement with the calibrated data of the Vector Field Magnetometer (VFM),which is the primary vector magnetometer of the satellite.These calibration efforts have significantly improved the accuracy of the FGM measurements,which are now providing reliable data for geomagnetic field studies that promise to advance our understanding of the Earth’s magnetic environment.展开更多
We consider the multiplicity of solutions to a p(x)-Laplacian problem involving supercritical Sobolev growth via Ricceri’s principle.By means of truncation combined with De Giorgi iteration,we can extend the results ...We consider the multiplicity of solutions to a p(x)-Laplacian problem involving supercritical Sobolev growth via Ricceri’s principle.By means of truncation combined with De Giorgi iteration,we can extend the results of subcritical and critical growth to supercritical growth and obtain at least three solutions to the p(x)-Laplacian problem.展开更多
Elucidating the relationship between spin excitations and fermiology is essential for clarifying the pairing mechanism in iron-based superconductors(FeSCs).Here,we report inelastic neutron scattering results on the ho...Elucidating the relationship between spin excitations and fermiology is essential for clarifying the pairing mechanism in iron-based superconductors(FeSCs).Here,we report inelastic neutron scattering results on the hole overdoped Ba_(0.4)K_(0.6)Fe_(2)As_(2) near a Lifshitz transition,where the electron pocket at M point is nearly replaced by four hole pockets.In the normal state,the spin excitations is observed at incommensurate wave vectors with a chimney-like dispersion.By cooling down to the superconducting state,a neutron spin resonance mode emerges with a peak energy of Er=14-15 meV,weakly modulated along the L-direction.The incommensurability notably increases at low energies,giving rise to downward dispersions of the resonance mode.This behavior contrasts sharply with the upward dispersions of resonance observed in optimally doped Ba_(0.67)K_(0.33)Fe_(2)As_(2) contributed by the hole to electron scattering,but resembles those in KFe_(2)As_(2) and KCa_(2)Fe_(4)As_(4)F_(2) where the fermiology is dominated by hole pockets.These results highlight the critical role of electronic structure modifications near the Fermi level,especially in governing interband scattering under imperfect nesting conditions,which fundamentally shape the spin dynamics of FeSCs.展开更多
Objective This study aimed to investigate the neuroprotective effects of cholecalciferol cholesterol emulsion(CCE),a vitamin D(VD)precursor,in a murine model of acute cerebral infarction(ACI)and to elucidate the role ...Objective This study aimed to investigate the neuroprotective effects of cholecalciferol cholesterol emulsion(CCE),a vitamin D(VD)precursor,in a murine model of acute cerebral infarction(ACI)and to elucidate the role of the Nrf2 signaling pathway in mediating these effects.Methods Forty C57BL/6J mice(male and female)were divided into five groups(n=10 per group):control,control+CCE,ACI,ACI+CCE,and ACI+CCE+ML385(an Nrf2 inhibitor).ACI was induced by middle cerebral artery occlusion(MCAO).CCE was administered for three weeks prior to ACI induction,and ML385 was administered intravenously to inhibit Nrf2.Neurological function,brain edema,and infarct size,as well as inflammatory and apoptotic marker levels,were assessed post-ACI.Statistical analyses were conducted via one-way ANOVA and Student's t test,with P<0.05 considered significant.Results Compared to ACI group,CCE significantly reduced neurological deficits,brain edema,and infarct size(P<0.01).The ACI+CCE group presented improved short-term memory retention,as evidenced by shorter avoidance latency in shuttle avoidance tests(P<0.01).CCE administration attenuated the expression of inflammatory markers(IL-6,MIF,Lp-PLA2)while increasing IL-10 levels(P<0.001).Furthermore,CCE increased Nrf2 and HO-1 expression and reduced apoptosis by decreasing the Bax/Bcl-2 ratio in brain tissue(P<0.001).ML385 abolished these neuroprotective effects,confirming the role of the Nrf2 pathway in mediating the benefits of VD.Conclusion VD,via VD receptor-mediated activation of the Nrf2/HO-1 pathway,reduces inflammation,apoptosis,and neurological damage following ACI.These findings support the therapeutic potential of VD in the treatment of ischemic stroke and highlight the importance of Nrf2 in mediating these effects.展开更多
The source region of the Yellow River, accounting for over 38% of its total runoff, is a critical catchment area,primarily characterized by alpine grasslands. In 2005, the Maqu land surface processes observational sit...The source region of the Yellow River, accounting for over 38% of its total runoff, is a critical catchment area,primarily characterized by alpine grasslands. In 2005, the Maqu land surface processes observational site was established to monitor climate, land surface dynamics, and hydrological variability in this region. Over a 10-year period(2010–19), an extensive observational dataset was compiled, now available to the scientific community. This dataset includes comprehensive details on site characteristics, instrumentation, and data processing methods, covering meteorological and radiative fluxes, energy exchanges, soil moisture dynamics, and heat transfer properties. The dataset is particularly valuable for researchers studying land surface processes, land–atmosphere interactions, and climate modeling, and may also benefit ecological, hydrological, and water resource studies. The report ends with a discussion on perspectives and challenges of continued observational monitoring in this region, focusing on issues such as cryosphere influences, complex topography,and ecological changes like the encroachment of weeds and scrubland.展开更多
Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how woul...Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.展开更多
Tirzepatide,a dual GIP/GLP-1 receptor agonist,has shown unprecedented efficacy in weight loss and improving metabolic parameters in clinical trials.However,the durability of these benefits after treatment cessation re...Tirzepatide,a dual GIP/GLP-1 receptor agonist,has shown unprecedented efficacy in weight loss and improving metabolic parameters in clinical trials.However,the durability of these benefits after treatment cessation remains poorly understood.This study aimed to investigate the effect of tirzepatide cessation on body weight change in people with obesity or overweight.This real-world,observational 26-week follow-up study included participants who completed 52 weeks'study treatment during SURMOUNT-CN(NCT05024032).The analysis excluded participants who received anti-obesity medications or bariatric procedures during the 26-week follow-up.Key outcomes were the changes in body weight and waist circumference after 26 weeks,from treatment cessation(Week 52)and trial baseline(Week 0),by the SURMOUNT-CN treatment groups(tirzepatide 10 or 15 mg,or placebo).Overall,152 participants were included(tirzepatide 10 mg:n=57;tirzepatide 15 mg:n=51;placebo:n=44).Following treatment cessation(Week 52),the mean(SD)percentage changes in body weight at Week 78 were 9.1%(7.4),12.3%(9.9),and 1.8%(5.2),and the absolute changes in waist circumference were 2.9 cm(7.5),5.5 cm(6.5)and-0.5 cm(5.6),in tirzepatide 10 and 15 mg,and placebo groups,respectively.From trial baseline to Week 78,the mean(SD)net percentage weight changes were-8.7%(6.9),-10.6%(10.2),and-2.5%(7.0),and the changes in waist circumference were-10.5 cm(8.1),-10.6 cm(9.3)and-4.0 cm(7.2),in the tirzepatide 10 and 15 mg,and placebo groups,respectively.At Week 78,residual improvements in multiple cardiometabolic indicators were evident in the tirzepatide groups.Despite weight gain following tirzepatide cessation,participants achieved a large net weight loss and reduction in waist circumference from trial baseline to Week 78,with residual improvements in several cardiometabolic indicators.展开更多
As a novel economic paradigm that drives high-quality economic development,the digital economy(DE)can potentially significantly enhance the utilization efficiency of ecological resources and improve human well-being.B...As a novel economic paradigm that drives high-quality economic development,the digital economy(DE)can potentially significantly enhance the utilization efficiency of ecological resources and improve human well-being.Based on panel data from 285 prefecture-level cities in China spanning 2011-2021,this study empirically investigates the direct effects,transmission mechanisms,and spatial spillover effects of the DE on ecological welfare performance(EWP)using benchmark regression,intermediary effects,and spatial Durbin models.The results show that the DE significantly improved EWP in Chinese cities.This conclusion remains valid even after controlling for relevant influencing factors.Two transmission paths—upgrading of the industrial structure(UIS)and green innovation(GI)—significantly impacted EWP,as verified by the mediation effect model.Additionally,the mediating effect of the UIS was stronger than that of GI.Spatial heterogeneity tests show that the DE had significant effects on the EWP of eastern cities,with little impact on the central and western cities.Accordingly,grounded in regional developmental disparities,the empowering effects of the DE must be fully harnessed to foster an ecological civilization and enhance the well-being of the populace.展开更多
Flash floods are characterized by their destructive power,rapid onset,and unpredictability,often causing severe damage to both natural environments and socioeconomic systems.Understanding the detailed disaster-causing...Flash floods are characterized by their destructive power,rapid onset,and unpredictability,often causing severe damage to both natural environments and socioeconomic systems.Understanding the detailed disaster-causing mechanisms of flash floods is critical for eff ective disaster risk reduction.However,current studies have not captured the comprehensive circumstance of flash floods that integrates environment,hazard,and exposure from the perspective of disaster systems theory.To address the gap,this study established a systematic framework for comprehensively evaluating flash floods disaster-causing mechanisms in ungauged mountainous micro-watersheds by integrating multi-source data,including remote sensing observations,meteorological station data,unmanned aerial vehicle measurements,and participatory geographic information system data,with hydrological-hydrodynamic and statistical models.The proposed framework consists of four interconnected steps:design storm estimation,flash flood process simulation,critical rainfall calculation,and disaster loss evaluation.Through a case study conducted in Qialegeer Village,Xinjiang,China,we demonstrated the framework's applicability by reconstructing flash flood scenarios,including the 2017 event as well as those of 10 and 20 years return periods.The results demonstrate that our framework robustly and systematically elucidates flash flood disaster process in the region with high reliability.Furthermore,it is adaptable to other ungauged mountainous micro-watersheds.This framework ultimately serves to enhance disaster risk mitigation and build resilience in vulnerable mountainous communities.展开更多
Wire arc additive manufacturing(WAAM)is one of the most promising approaches to manufacturing large and complex metal components owing to its low cost and high efficiency.However,pores and coarse columnar grains cause...Wire arc additive manufacturing(WAAM)is one of the most promising approaches to manufacturing large and complex metal components owing to its low cost and high efficiency.However,pores and coarse columnar grains caused by thermal accumulation in WAAM significantly decrease the strength and increase the anisotropy,preventing the achievement of both high strength and isotropy.In this study,the strength and anisotropy of AlMg-Sc-Zr alloys were improved by regulating heat input.The results indicated that as the heat input increased from 60 to 99 J/mm,all the components had lower porosity(lower than 0.04%),the size of the Al_(3)(Sc_(1-x),Zr_(x))phases decreased,and the number density increased.The average grain size gradually decreased,and the grain morphologies transformed from coarse equiaxed grain(CEG)+fine equiaxed grain(FEG)to FEG owing to the increase in Al_(3)(Sc_(1-x),Zr_(x))phases with increasing heat input.After heat treatment at 325℃for 6 h,high-density dispersed Al_(3)Sc phases(<10 nm)precipitated.The alloy possessed the highest strength at 79 J/mm,ultimate tensile strength(UTS)of approximately 423±3 MPa,and in-plane anisotropy of approximately 4.3%.At a heat input of 99 J/mm,the in-plane anisotropy decreased to 1.2%and UTS reached 414±5 MPa.The reduction in the CEG prolonged the crack propagation path,which improved the UTS in the vertical direction and reduced the anisotropy.Theoretical calculations indicated that the main strengthening mechanisms were solid solution and precipitation strengthening.This study lays the theoretical foundations for WAAM-processed high-strength and isotropic Al alloy components.展开更多
Angle-resolved photoemission spectroscopy(ARPES)has become a cornerstone technique for elucidating the electronic structures of emergent quantum materials.Among these,kagome materials—distinguished by their two-dimen...Angle-resolved photoemission spectroscopy(ARPES)has become a cornerstone technique for elucidating the electronic structures of emergent quantum materials.Among these,kagome materials—distinguished by their two-dimensional lattice of corner-sharing triangles—provide a fertile ground for investigating exotic quantum phenomena,driven by geometric frustration,electronic correlation,and topology.In this review,we present an overview of recent ARPES studies on transition-metal kagome materials.We first outline the fundamental features of their electronic structures,including van Hove singularities,Dirac points,and flat bands,and discuss the novel quantum states that arise from many-body interactions within the kagome lattice.We then highlight key ARPES investigations into these unique electronic structures,detailing their manifestation and associated quantum states in representative kagome materials.Finally,we offer a forward-looking perspective on the potential of ARPES to uncover new quantum phenomena and its broader implications for the study of underlying physics in kagome materials.展开更多
Previous studies have indicated that sediment gravity flow deposits developed in lacustrine active extensional rift basins are primarily influenced by tectonics and to a lesser extent by climate.Our present work revea...Previous studies have indicated that sediment gravity flow deposits developed in lacustrine active extensional rift basins are primarily influenced by tectonics and to a lesser extent by climate.Our present work reveals that climate can obscure the effect of tectonic subsidence by regulating sediment supply;conversely,tectonics can impede the sedimentary manifestation of climatic impacts.Here a case study has been presented to assess the impact of climate-modulated rapid lake-level rise and tectonic subsidence on the development of coarse-grained gravity flow deposits in the Dongying rift margin of the Bohai Bay Basin,eastern China.The lithofacies analysis reveals frequent bed amalgamation,abundant thick massive coarse-grained deposits,widespread cross bedding and plant fragments,and incomplete composite bed formed by high-energy erosion,indicating that the hyperpycnal flow is an important mechanism driving the deposition of these coarse-grained sediments.Detailed sequence stratigraphic analysis and sediment dispersal pattern suggest that the long-striped nearshore subaqueous fan systems induced by outburst-flood hyperpycnal flow distributed along the border fault,are primarily controlled by long-term tectonics,while the rapid rise of lake level driven by short-term climate change possibly intensifies seasonal flood-generated hyperpycnal flow occurrences and consequently promotes the basinal fan progradation.The maximum scale of these coarse-grained gravity flow deposits of the basinal fan systems are typically attained during the transgressive systems tract,which deviates from the classical sequence stratigraphic model.Furthermore,it presented a continuous transition from the proximal to the distal part,encompassing traction flows and turbidity currents during the periods of relatively stable tectonics.Nevertheless,gravel-rich debris flows appear to predominate the dispersion of coarse-grained sediments during periods characterized by intense tectonic activity.The coarse-grained gravity flow deposits in the lacustrine rift margin reported here,challenge the traditional beliefs:this study suggests that subaqueous deposits abundantly preserved in the transgressive setting.展开更多
Anthocyanin is widely acknowledged as a crucial component contributing to apple fruit quality.However,research on the influence of NAC transcription factors on anthocyanin accumulation in red flesh apple is limited.In...Anthocyanin is widely acknowledged as a crucial component contributing to apple fruit quality.However,research on the influence of NAC transcription factors on anthocyanin accumulation in red flesh apple is limited.In this study,a NAC transcription factor MdNAC77L was identified as highly related to the change of anthocyanin content,based on a combined anthocyanin metabolome and transcriptome analysis.Overexpression of MdNAC77L significantly increased the accumulation of anthocyanin in both apple and strawberry fruits,along with the expression of several anthocyanin-related enzymes.Molecular-level analyses demonstrated that MdNAC77L was directly combined with the promoters of three pivotal enzymes(dihydroflavonol 4-reductase,anthocyanin synthase,and UDP-flavonoid glucosyltransferase)of anthocyanin biosynthetic pathway.We found that ABA strongly induced the expression of MdNAC77L,which activated the expression of three downstream target genes.In addition,MdNAC77L showed higher transcript accumulation in flesh with lower anthocyanin content than that in red peel.We revealed the new core factor,MdNAC77L,involved in anthocyanin accumulation in apple red flesh.This research provides a fresh perspective on the intricate regulatory mechanisms governing anthocyanin biosynthesis in red-fleshed apples.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.52150410427)the Key Support Program for Foreign Experts of the Ministry of Science and Technology of the People's Republic of China(No.wgxz2022057)funding for post-doctoral work by the Department of Human Resources and Social Security of Hubei Province。
文摘Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments.
基金supported by the Basic Key Research Program of Basic Strengthening Plan(No.2021-JCJQ-ZD-075-11)the CISRI Independent Research and Development Programs(Nos.21H62580Z and No.23H60450Z)the National Natural Science Foundation of China(Grant No.52374365).
文摘Wire arc additive manufacturing(WAAM)technique is a promising approach to producing large-scale metal components due to high deposition efficiency and low production cost.However,fundamental research about WAAM-processed Al-Mg-Sc-Zr alloy was still fewer.In this study,Al-6.54Mg-0.36Sc-0.11Zr(wt%)components were successfully manufactured by WAAM with an interlayer temperature at 100℃(named IW)and continuous printing(named CP),and the corresponding porosity,microstructure,and mechanical properties of components were studied in detail.The porosity of components as-deposited was relatively low,about 0.385%and 0.116%,respectively.The microstructures of the two components exhibited the same distribution characteristics in XZ and YZ planes:fine equiaxed grains(FEG)at remelted zone+FEG and coarse equiaxed grain(CEG)alternative distribution at middle zone+FEG at the top zone of the molten pool.The average grain size of component IW was about 10.51±6.01μm,and that of component CP significantly increased,to about 11.85±5.86μm.The short-circuit transition mode of cold metal transfer technology and the heterogeneous nucleation effect of primary Al3(Sc,Zr)and Al3(Sc,Zr,Ti)phases together promoted the formation of equiaxed grains and refined the microstructures.After heat treatment at 325℃and 6 h,nano-Al3Sc precipitated with a size of about 15-50 nm.The yield strength(YS)of components IW and CP increased from 171±3 to 261±1 MPa and 168±7 to 240±17 MPa,respectively.Component IW had the highest ultimate tensile strength,about 400±1 MPa.For WAAMprocessed Al-Mg-Sc-Zr alloys,the contribution of the strengthening mechanism to YS was solid solution strengthening>precipitation strengthening>fine grain strengthening>dislocation strengthening.
文摘High-precision magnetic field measurements are crucial for understanding Earth’s internal structure,space environment,and dynamic geomagnetic variations.Data from the Fluxgate Magnetometer (FGM) on the Macao Science Satellite-1A (MSS-1A),added to data from other space-based magnetometers,should increase significantly the ability of scientists to observe changes in Earth’s magnetic field over time and space.Additionally,the MSS-1A’s FGM is intended to help identify magnetic disturbances affecting the spacecraft itself.This report focuses on the in-flight calibration of the MSS-1 FGM.A scalar calibration,independent of geomagnetic field models,was performed to correct offsets,sensitivities,and misalignment angles of the FGM.Using seven months of data,we find that the in-flight calibration parameters show good stability.We determined Euler angles describing the rotational relationship between the FGM and the Advanced Stellar Compass (ASC) coordinate system using two approaches:calibration with the CHAOS-7 geomagnetic field model,and simultaneous estimation of Euler angles and Gaussian spherical harmonic coefficients through self-consistent modeling.The accuracy of Euler angles describing the rotation was better than 18 arcsec.The calibrated FGM data exhibit good agreement with the calibrated data of the Vector Field Magnetometer (VFM),which is the primary vector magnetometer of the satellite.These calibration efforts have significantly improved the accuracy of the FGM measurements,which are now providing reliable data for geomagnetic field studies that promise to advance our understanding of the Earth’s magnetic environment.
基金supported by the Fundamental Research Funds for the Central Universities(2024KYJD2006).
文摘We consider the multiplicity of solutions to a p(x)-Laplacian problem involving supercritical Sobolev growth via Ricceri’s principle.By means of truncation combined with De Giorgi iteration,we can extend the results of subcritical and critical growth to supercritical growth and obtain at least three solutions to the p(x)-Laplacian problem.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406100,2018YFA0704200,2022YFA1403400 and 2021YFA1400400)the National Natural Science Foundation of China(Grant Nos.11822411 and 12274444)+2 种基金the Strategic Priority Research Program(B)of the CAS(Grant Nos.XDB25000000 and XDB33000000)K.C.Wong Education Foundation(GJTD-2020-01)AP by HBNI-RRCAT and MPCST under the FTYS program。
文摘Elucidating the relationship between spin excitations and fermiology is essential for clarifying the pairing mechanism in iron-based superconductors(FeSCs).Here,we report inelastic neutron scattering results on the hole overdoped Ba_(0.4)K_(0.6)Fe_(2)As_(2) near a Lifshitz transition,where the electron pocket at M point is nearly replaced by four hole pockets.In the normal state,the spin excitations is observed at incommensurate wave vectors with a chimney-like dispersion.By cooling down to the superconducting state,a neutron spin resonance mode emerges with a peak energy of Er=14-15 meV,weakly modulated along the L-direction.The incommensurability notably increases at low energies,giving rise to downward dispersions of the resonance mode.This behavior contrasts sharply with the upward dispersions of resonance observed in optimally doped Ba_(0.67)K_(0.33)Fe_(2)As_(2) contributed by the hole to electron scattering,but resembles those in KFe_(2)As_(2) and KCa_(2)Fe_(4)As_(4)F_(2) where the fermiology is dominated by hole pockets.These results highlight the critical role of electronic structure modifications near the Fermi level,especially in governing interband scattering under imperfect nesting conditions,which fundamentally shape the spin dynamics of FeSCs.
基金supported by the Medical Science Research Project Program of Hebei Province(20211722).
文摘Objective This study aimed to investigate the neuroprotective effects of cholecalciferol cholesterol emulsion(CCE),a vitamin D(VD)precursor,in a murine model of acute cerebral infarction(ACI)and to elucidate the role of the Nrf2 signaling pathway in mediating these effects.Methods Forty C57BL/6J mice(male and female)were divided into five groups(n=10 per group):control,control+CCE,ACI,ACI+CCE,and ACI+CCE+ML385(an Nrf2 inhibitor).ACI was induced by middle cerebral artery occlusion(MCAO).CCE was administered for three weeks prior to ACI induction,and ML385 was administered intravenously to inhibit Nrf2.Neurological function,brain edema,and infarct size,as well as inflammatory and apoptotic marker levels,were assessed post-ACI.Statistical analyses were conducted via one-way ANOVA and Student's t test,with P<0.05 considered significant.Results Compared to ACI group,CCE significantly reduced neurological deficits,brain edema,and infarct size(P<0.01).The ACI+CCE group presented improved short-term memory retention,as evidenced by shorter avoidance latency in shuttle avoidance tests(P<0.01).CCE administration attenuated the expression of inflammatory markers(IL-6,MIF,Lp-PLA2)while increasing IL-10 levels(P<0.001).Furthermore,CCE increased Nrf2 and HO-1 expression and reduced apoptosis by decreasing the Bax/Bcl-2 ratio in brain tissue(P<0.001).ML385 abolished these neuroprotective effects,confirming the role of the Nrf2 pathway in mediating the benefits of VD.Conclusion VD,via VD receptor-mediated activation of the Nrf2/HO-1 pathway,reduces inflammation,apoptosis,and neurological damage following ACI.These findings support the therapeutic potential of VD in the treatment of ischemic stroke and highlight the importance of Nrf2 in mediating these effects.
基金supported by the National Natural Science Foundation of China for Distinguished Young Scholars (Grant No.42325502)the 2nd Scientific Expedition to the Qinghai–Tibet Plateau (Grant No.2019QZKK0102)+3 种基金the West Light Foundation of the Chinese Academy of Sciences (Grant No.xbzg-zdsys-202215)the Science and Technology Research Plan of Gansu Province (Grant Nos.23JRRA654 and 20JR10RA070)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No.QCH2019004)iLEAPS (integrated Land Ecosystem–Atmosphere Processes Study)。
文摘The source region of the Yellow River, accounting for over 38% of its total runoff, is a critical catchment area,primarily characterized by alpine grasslands. In 2005, the Maqu land surface processes observational site was established to monitor climate, land surface dynamics, and hydrological variability in this region. Over a 10-year period(2010–19), an extensive observational dataset was compiled, now available to the scientific community. This dataset includes comprehensive details on site characteristics, instrumentation, and data processing methods, covering meteorological and radiative fluxes, energy exchanges, soil moisture dynamics, and heat transfer properties. The dataset is particularly valuable for researchers studying land surface processes, land–atmosphere interactions, and climate modeling, and may also benefit ecological, hydrological, and water resource studies. The report ends with a discussion on perspectives and challenges of continued observational monitoring in this region, focusing on issues such as cryosphere influences, complex topography,and ecological changes like the encroachment of weeds and scrubland.
基金supported by grants from the National Natural Science Foundation of China for Excellent Young Scientists Fund Program(No.42222105)the National Natural Science Foundation of China General Program(No.42171144)+1 种基金the Assessment of Ecosystem Carbon Stock and Turnover Patterns in Qinghai Province(No.2021-SFA7-1-1)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2021QZKK0100)。
文摘Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.
文摘Tirzepatide,a dual GIP/GLP-1 receptor agonist,has shown unprecedented efficacy in weight loss and improving metabolic parameters in clinical trials.However,the durability of these benefits after treatment cessation remains poorly understood.This study aimed to investigate the effect of tirzepatide cessation on body weight change in people with obesity or overweight.This real-world,observational 26-week follow-up study included participants who completed 52 weeks'study treatment during SURMOUNT-CN(NCT05024032).The analysis excluded participants who received anti-obesity medications or bariatric procedures during the 26-week follow-up.Key outcomes were the changes in body weight and waist circumference after 26 weeks,from treatment cessation(Week 52)and trial baseline(Week 0),by the SURMOUNT-CN treatment groups(tirzepatide 10 or 15 mg,or placebo).Overall,152 participants were included(tirzepatide 10 mg:n=57;tirzepatide 15 mg:n=51;placebo:n=44).Following treatment cessation(Week 52),the mean(SD)percentage changes in body weight at Week 78 were 9.1%(7.4),12.3%(9.9),and 1.8%(5.2),and the absolute changes in waist circumference were 2.9 cm(7.5),5.5 cm(6.5)and-0.5 cm(5.6),in tirzepatide 10 and 15 mg,and placebo groups,respectively.From trial baseline to Week 78,the mean(SD)net percentage weight changes were-8.7%(6.9),-10.6%(10.2),and-2.5%(7.0),and the changes in waist circumference were-10.5 cm(8.1),-10.6 cm(9.3)and-4.0 cm(7.2),in the tirzepatide 10 and 15 mg,and placebo groups,respectively.At Week 78,residual improvements in multiple cardiometabolic indicators were evident in the tirzepatide groups.Despite weight gain following tirzepatide cessation,participants achieved a large net weight loss and reduction in waist circumference from trial baseline to Week 78,with residual improvements in several cardiometabolic indicators.
基金funded by the Natural Science Foundation of Shandong Province[Grant No.ZR2022MD104]Rizhao Natural Science Foundation Youth Fund Project[Grant No.RZ2021ZR36]Taishan Scholars Youth Expert Support Plan of Shandong Province[Grant No.tsqn202306183].
文摘As a novel economic paradigm that drives high-quality economic development,the digital economy(DE)can potentially significantly enhance the utilization efficiency of ecological resources and improve human well-being.Based on panel data from 285 prefecture-level cities in China spanning 2011-2021,this study empirically investigates the direct effects,transmission mechanisms,and spatial spillover effects of the DE on ecological welfare performance(EWP)using benchmark regression,intermediary effects,and spatial Durbin models.The results show that the DE significantly improved EWP in Chinese cities.This conclusion remains valid even after controlling for relevant influencing factors.Two transmission paths—upgrading of the industrial structure(UIS)and green innovation(GI)—significantly impacted EWP,as verified by the mediation effect model.Additionally,the mediating effect of the UIS was stronger than that of GI.Spatial heterogeneity tests show that the DE had significant effects on the EWP of eastern cities,with little impact on the central and western cities.Accordingly,grounded in regional developmental disparities,the empowering effects of the DE must be fully harnessed to foster an ecological civilization and enhance the well-being of the populace.
基金funded by the Third Xinjiang Scientific Expedition Program(Grant No.2022xjkk0601)National Natural Science Foundation of China(Grant Nos.42471085,U22B2011)Natural Science Foundation of Hubei Province(2023AFB823)。
文摘Flash floods are characterized by their destructive power,rapid onset,and unpredictability,often causing severe damage to both natural environments and socioeconomic systems.Understanding the detailed disaster-causing mechanisms of flash floods is critical for eff ective disaster risk reduction.However,current studies have not captured the comprehensive circumstance of flash floods that integrates environment,hazard,and exposure from the perspective of disaster systems theory.To address the gap,this study established a systematic framework for comprehensively evaluating flash floods disaster-causing mechanisms in ungauged mountainous micro-watersheds by integrating multi-source data,including remote sensing observations,meteorological station data,unmanned aerial vehicle measurements,and participatory geographic information system data,with hydrological-hydrodynamic and statistical models.The proposed framework consists of four interconnected steps:design storm estimation,flash flood process simulation,critical rainfall calculation,and disaster loss evaluation.Through a case study conducted in Qialegeer Village,Xinjiang,China,we demonstrated the framework's applicability by reconstructing flash flood scenarios,including the 2017 event as well as those of 10 and 20 years return periods.The results demonstrate that our framework robustly and systematically elucidates flash flood disaster process in the region with high reliability.Furthermore,it is adaptable to other ungauged mountainous micro-watersheds.This framework ultimately serves to enhance disaster risk mitigation and build resilience in vulnerable mountainous communities.
基金supported by National Key Research and Development Program(Grant No.2024YFB4609700)the National Natural Science Foundation of China(Grant No.52374365)。
文摘Wire arc additive manufacturing(WAAM)is one of the most promising approaches to manufacturing large and complex metal components owing to its low cost and high efficiency.However,pores and coarse columnar grains caused by thermal accumulation in WAAM significantly decrease the strength and increase the anisotropy,preventing the achievement of both high strength and isotropy.In this study,the strength and anisotropy of AlMg-Sc-Zr alloys were improved by regulating heat input.The results indicated that as the heat input increased from 60 to 99 J/mm,all the components had lower porosity(lower than 0.04%),the size of the Al_(3)(Sc_(1-x),Zr_(x))phases decreased,and the number density increased.The average grain size gradually decreased,and the grain morphologies transformed from coarse equiaxed grain(CEG)+fine equiaxed grain(FEG)to FEG owing to the increase in Al_(3)(Sc_(1-x),Zr_(x))phases with increasing heat input.After heat treatment at 325℃for 6 h,high-density dispersed Al_(3)Sc phases(<10 nm)precipitated.The alloy possessed the highest strength at 79 J/mm,ultimate tensile strength(UTS)of approximately 423±3 MPa,and in-plane anisotropy of approximately 4.3%.At a heat input of 99 J/mm,the in-plane anisotropy decreased to 1.2%and UTS reached 414±5 MPa.The reduction in the CEG prolonged the crack propagation path,which improved the UTS in the vertical direction and reduced the anisotropy.Theoretical calculations indicated that the main strengthening mechanisms were solid solution and precipitation strengthening.This study lays the theoretical foundations for WAAM-processed high-strength and isotropic Al alloy components.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12488201,12074411,12374066,12374154,and 12494593)the National Key Research and Development Program of China(Grant No.2022YFA1403900,2021YFA1401800,2022YFA1604200,2023YFA1406002,2024YFA1408301,and 2024YFA1400026)+3 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant Nos.XDB25000000 and XDB33000000)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301800)the Youth Innovation Promotion Association of CAS(Grant No.Y2021006)Synergetic Extreme Condition User Facility(SECUF).
文摘Angle-resolved photoemission spectroscopy(ARPES)has become a cornerstone technique for elucidating the electronic structures of emergent quantum materials.Among these,kagome materials—distinguished by their two-dimensional lattice of corner-sharing triangles—provide a fertile ground for investigating exotic quantum phenomena,driven by geometric frustration,electronic correlation,and topology.In this review,we present an overview of recent ARPES studies on transition-metal kagome materials.We first outline the fundamental features of their electronic structures,including van Hove singularities,Dirac points,and flat bands,and discuss the novel quantum states that arise from many-body interactions within the kagome lattice.We then highlight key ARPES investigations into these unique electronic structures,detailing their manifestation and associated quantum states in representative kagome materials.Finally,we offer a forward-looking perspective on the potential of ARPES to uncover new quantum phenomena and its broader implications for the study of underlying physics in kagome materials.
基金supported by the National Natural Science Foundation of China(Nos.42172109,41872113,42172108)China National Petroleum Corporation-China University of Petroleum(Beijing)strategic cooperation science and technology project(ZLZX2020-02)+2 种基金Science Foundation of China University of Petroleum(Beijing)(Nos.2462020BJRC002,2462020YXZZ020)Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX1166)Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202201511).
文摘Previous studies have indicated that sediment gravity flow deposits developed in lacustrine active extensional rift basins are primarily influenced by tectonics and to a lesser extent by climate.Our present work reveals that climate can obscure the effect of tectonic subsidence by regulating sediment supply;conversely,tectonics can impede the sedimentary manifestation of climatic impacts.Here a case study has been presented to assess the impact of climate-modulated rapid lake-level rise and tectonic subsidence on the development of coarse-grained gravity flow deposits in the Dongying rift margin of the Bohai Bay Basin,eastern China.The lithofacies analysis reveals frequent bed amalgamation,abundant thick massive coarse-grained deposits,widespread cross bedding and plant fragments,and incomplete composite bed formed by high-energy erosion,indicating that the hyperpycnal flow is an important mechanism driving the deposition of these coarse-grained sediments.Detailed sequence stratigraphic analysis and sediment dispersal pattern suggest that the long-striped nearshore subaqueous fan systems induced by outburst-flood hyperpycnal flow distributed along the border fault,are primarily controlled by long-term tectonics,while the rapid rise of lake level driven by short-term climate change possibly intensifies seasonal flood-generated hyperpycnal flow occurrences and consequently promotes the basinal fan progradation.The maximum scale of these coarse-grained gravity flow deposits of the basinal fan systems are typically attained during the transgressive systems tract,which deviates from the classical sequence stratigraphic model.Furthermore,it presented a continuous transition from the proximal to the distal part,encompassing traction flows and turbidity currents during the periods of relatively stable tectonics.Nevertheless,gravel-rich debris flows appear to predominate the dispersion of coarse-grained sediments during periods characterized by intense tectonic activity.The coarse-grained gravity flow deposits in the lacustrine rift margin reported here,challenge the traditional beliefs:this study suggests that subaqueous deposits abundantly preserved in the transgressive setting.
基金supported by the Scientific Research Foundation of Xuzhou Academy of Agricultural Sciences(Grant No.RC2021002).
文摘Anthocyanin is widely acknowledged as a crucial component contributing to apple fruit quality.However,research on the influence of NAC transcription factors on anthocyanin accumulation in red flesh apple is limited.In this study,a NAC transcription factor MdNAC77L was identified as highly related to the change of anthocyanin content,based on a combined anthocyanin metabolome and transcriptome analysis.Overexpression of MdNAC77L significantly increased the accumulation of anthocyanin in both apple and strawberry fruits,along with the expression of several anthocyanin-related enzymes.Molecular-level analyses demonstrated that MdNAC77L was directly combined with the promoters of three pivotal enzymes(dihydroflavonol 4-reductase,anthocyanin synthase,and UDP-flavonoid glucosyltransferase)of anthocyanin biosynthetic pathway.We found that ABA strongly induced the expression of MdNAC77L,which activated the expression of three downstream target genes.In addition,MdNAC77L showed higher transcript accumulation in flesh with lower anthocyanin content than that in red peel.We revealed the new core factor,MdNAC77L,involved in anthocyanin accumulation in apple red flesh.This research provides a fresh perspective on the intricate regulatory mechanisms governing anthocyanin biosynthesis in red-fleshed apples.
