Stent-grafts were commercialized rapidly and gained a broad clinical acceptance over the past two decades. However,relatively more recent recognition of particular stent-graft design shortcomings have been identified ...Stent-grafts were commercialized rapidly and gained a broad clinical acceptance over the past two decades. However,relatively more recent recognition of particular stent-graft design shortcomings have been identified which need to be addressed. It appears that various stent-graft designs may be more or less resistant to metal fatigue and /or fabric abrasions which can lead to type III and type IV endoleaks over the long term. Therefore,it is necessary to investigate the fatigue performance of the most common stentgraft designs: Z-stents and ringed stents,in a long-term in vitro fatigue simulation environment. This paper aimed to analyze nondestructively( gross observations) and destructively( fabric characteristics,mechanical and chemical properties) in order to put forward suggestions to improve the fabric and stent characteristics that may prevent type III and IV endoleaks. The fabric supported with ringed stent-grafts remained nearly completely intact after 168h. However, the fabric supported with Z-stents demonstrated significant damage. Fabric characteristics and tensile strength of the fibers did not present a significant difference between the control and fatigue simulated specimens. The crystallinity declined for both specimens. The fatigue performance of fabrics supported with ringed stents appears to be superior to that supported with Z-stents. The potential for a dynamic and destructive interaction between the apices of Z-stents which can lead to fraying and /or tearing of the graft fabric must be addressed in future designs.展开更多
The surface morphology of free-surface PCL ringed spherulites was investigated by using atomic force microscopy. The spherulites were obtained by crystallization of PCL/PVC blends of different compositions. It was fou...The surface morphology of free-surface PCL ringed spherulites was investigated by using atomic force microscopy. The spherulites were obtained by crystallization of PCL/PVC blends of different compositions. It was found that the ringed spherulite exhibited regularly fluctuating rings on its surface. Compared with the bright-dark ring pattern of the spherulite under a polarizing microscope, it was proved that the optical characteristics of the ringed spherulite under polarizing microscope coincided with its surface characteristics. The bright rings in polarizing micrographs of the spherulite coincided with the convex rings on its surface, while the dark rings coincided with the concave rings.展开更多
The author first introduces the notion of affine structures on a ringed space and then obtains several related properties.Affine structures on a ringed space,arising from complex analytical spaces of algebraic schemes...The author first introduces the notion of affine structures on a ringed space and then obtains several related properties.Affine structures on a ringed space,arising from complex analytical spaces of algebraic schemes,behave like differential structures on a smooth manifold.As one does for differential manifolds,pseudogroups of affine transformations are used to define affine atlases on a ringed space.An atlas on a space is said to be an affine structure if it is maximal.An affine structure is said to be admissible if there is a sheaf on the underlying space such that they are coincide on all affine charts,which are in deed affine open sets of a scheme.In a rigour manner,a scheme is defined to be a ringed space with a specified affine structure if the affine structures make a contribution to the cases such as analytical spaces of algebraic schemes.Particularly,by the whole of affine structures on a space,two necessary and sufficient conditions,that two spaces are homeomorphic and that two schemes are isomorphic,coming from the main theorems of the paper,are obtained respectively.A conclusion is drawn that the whole of affine structures on a space and a scheme,as local data,encode and reflect the global properties of the space and the scheme,respectively.展开更多
The wood anatomy of corystosperms is fundamentally consistent with that of gymnosperms,yet their growth ring boundaries share anatomical features with extant angiosperms.This transitional morphology strongly supports ...The wood anatomy of corystosperms is fundamentally consistent with that of gymnosperms,yet their growth ring boundaries share anatomical features with extant angiosperms.This transitional morphology strongly supports the interpretation of corystosperms as an evolutionary intermediate between gymnosperms and angiosperms.The first application of X-Ray fluorescence(XRF)chemical analysis to fossil wood taxa of Fengweioxylon yielded the above conclusion.By using growth ring analysis and ecological reconstructions,we suggest that corystosperms were large evergreen trees with leaf retention periods of three to five years.They likely thrived in warm summer environments where prolonged foliage retention provided adaptive benefits.展开更多
The testing of large structures is limited by high costs and long cycles, making scaling methods an attractive solution. However, the scaling process of elastic rings introduces complexities in multi-parameter geometr...The testing of large structures is limited by high costs and long cycles, making scaling methods an attractive solution. However, the scaling process of elastic rings introduces complexities in multi-parameter geometric distortions, leading to a diminution in the predictive accuracy of the distorted similitude. To address this challenge, this study formulates a novel set of scaling laws, tailored to account for the intricate geometric distortions associated with elastic rings. The proposed scaling laws are formulated based on the intrinsic deformation characteristics of elastic rings, rather than the traditional systemic governing equations. Numerical and experimental cases are conducted to assess the efficacy and precision of the proposed scaling laws, and the obtained results are compared with those achieved by traditional methods. The outcomes demonstrate that the scaling laws put forth by this study significantly enhance the predictive capabilities for deformations of elastic rings.展开更多
Floating ring bearings are widely used in high-speed turbomachinery such as turbochargers and turbogenerators.Research-ers have recently explored various surface texturing strategies on the inner surface of floating r...Floating ring bearings are widely used in high-speed turbomachinery such as turbochargers and turbogenerators.Research-ers have recently explored various surface texturing strategies on the inner surface of floating rings to enhance bearing performance.In this study,the herring patterns are textured on the inner surface of the floating ring.This pattern is inspired by the secondary flight feathers of the Indian pigeon,which aid the bird in reducing viscous drag during flight.The result-ing Herringbone Textured Floating Ring Bearing(HTFRB)is investigated for its potential application in locomotive turbo-chargers.The HTFRB is numerically modeled using the Reynolds equation to evaluate the bearing's pressure distribution and static characteristics,including load-carrying capacity,power loss,and side leakage.Dynamic characteristics are determined by solving the zeroth-and first-order perturbed Reynolds equation.A Sobol sensitivity analysis is conducted to quantify the influence of groove parameters-helix angle,groove depth,groove width ratio,and number of grooves-on bearing performance metrics.An artificial intelligence-based optimization framework,integrating artificial neural networks and adaptive neuro-fuzzy inference systems,is developed to maximize load carrying capacity while minimiz-ing power loss,side leakage,and friction coefficient.The optimized texture parameters obtained from this framework are employed to validate the ANN model and evaluate the static and dynamic characteristics of the HTFRB.The dynamic coefficients of the HTFRB are further employed to evaluate the stability and robustness of the turbocharger rotor-HTFRB system.This study underscores the potential of combining bio-inspired texture design with numerical modeling and AI-based optimization to develop high-performance HTFRB.展开更多
This study examines the dynamics of axis-offset collisions between two vortex rings using particle image velocimetry(PIV)measurements.At a fixed Reynolds number,the influence of axial separation on the flow evolution ...This study examines the dynamics of axis-offset collisions between two vortex rings using particle image velocimetry(PIV)measurements.At a fixed Reynolds number,the influence of axial separation on the flow evolution is systematically investigated.Finite-time Lyapunov exponent(FTLE)fields and combined vorticity-velocity analyses reveal three distinct interaction regimes.(1)In the collision and radial outflow regime(H/R_(ring)0.893,where H is the axial separation distance and R_(ring)is the ring radius),vortex rings undergo axial compression and generate strong radial outflows,with negligible material exchange between oppositely signed vortices.(2)In the collision and rebound regime(H/R_(ring)=1.786),the rings—bearing the same sign—experience a near-elastic rebound,leading to disintegration without reconnection.(3)In the merging-splitting and recovery regime(H/R_(ring)=2.679),the rings exhibit transient merging followed by splitting and coherence recovery,accompanied by significant material exchange.For even larger offsets(H/R_(ring)=3.572),interactions are negligible.These findings categorize axis-offset vortex ring interactions into three regimes based on flow behavior and yield insights relevant to enhanced mixing and heat dissipation in engineering applications.展开更多
The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impac...The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impact of fluorination positions at side chains on NFREAs device performance remains scant.In this study,we introduce two isomeric NFREAs,designated as GA-2F-E and GA-2F,distinguished by their fluorination positions at the side chains.Both NFREAs share a thiophene[3,2-b]thiophene core,but their side chains differ:GA-2F-E features two(4-butylphenyl)-N-(4-fluorophenyl) amino groups,whereas GA-2F's side chains consist of bis(4-fluorophenyl)amino and bis(4-butylphenyl)amino groups attached to opposite sides of the core.To delve into the influence of fluorination positions on the optoelectronic properties,aggregation behavior,and overall efficiency of the acceptor molecules,a comprehensive investigation was conducted.The findings reveal that,despite similar photophysical properties and comparable absorption bandwidths,GA-2F-E,with fluorine atoms positioned on both sides of the molecular framework,demonstrates more compact π-π stacking,reduced bimolecular recombination,superior exciton transport,and a more balanced,higher mobility.As a result of these advantages,OSCs optimized with D18:GA-2F-E achieve a remarkable power conversion efficiency(PCE) of 16.45 %,surpassing the 15.83 %PCE of devices utilizing D18:GA-2F.This research underscores the potential of NFREAs in future applications and highlights the significance of fluorination positions in enhancing OSC performance,paving the way for the development of more efficient NFREAs.展开更多
A nonfused ring electron acceptor(NFREA),designated as TT-Ph-C6,has been synthesized with the aim of enhancing the power conversion efficiency(PCE)of organic solar cells(OSCs).By integrating asymmetric phenylalkylamin...A nonfused ring electron acceptor(NFREA),designated as TT-Ph-C6,has been synthesized with the aim of enhancing the power conversion efficiency(PCE)of organic solar cells(OSCs).By integrating asymmetric phenylalkylamino side groups,TT-Ph-C6 demonstrates excellent solubility and its crystal structure exhibits compact packing structures with a three-dimensional molecular stacking network.These structural attributes markedly promote exciton diffusion and charge carrier mobility,particularly advantageous for the fabrication of thick-film devices.TT-Ph-C6-based devices have attained a PCE of 18.01%at a film thickness of 100 nm,and even at a film thickness of 300 nm,the PCE remains at 14.64%,surpassing that of devices based on 2BTh-2F.These remarkable properties position TT-Ph-C6 as a highly promising NFREA material for boosting the efficiency of OSCs.展开更多
Objective:Ring finger protein 145(RNF145),an E3 ubiquitin ligase,is significantly upregulated in hepatocellular carcinoma(HCC).However,its role in HCC remains unknown.The study aimed to investigate the functions and u...Objective:Ring finger protein 145(RNF145),an E3 ubiquitin ligase,is significantly upregulated in hepatocellular carcinoma(HCC).However,its role in HCC remains unknown.The study aimed to investigate the functions and underlying mechanisms of RNF145 in HCC.Methods:The role of RNF145 in HCC was investigated using data from The Cancer Genome Atlas(TCGA)and in vitro experimental assays.Its oncogenic functions were assessed using the transwell migration assay and the wound-healing assay.The molecular mechanism was explored through protein immunoprecipitation and western blot analyses.Data from public databases were analyzed to correlate RNF145 expression with clinicopathological features.Univariate and multivariate Cox analyses established RNF145 as an independent prognostic factor.Subsequently,a prognostic nomogram was constructed.Results:RNF145 was upregulated in HCC.The expression level of RNF145 in HCC showed significant correlations with histological grade,pathological stage,and vascular invasion.Functionally,knockdown of RNF145 effectively abolished the migratory and invasive capacities of HCC cells.This pro-metastatic effect is mediated through the RNF145-driven ubiquitination and subsequent degradation of protocadherin 9(PCDH9).Conclusion:Our findings confirm the significant upregulation of RNF145 in HCC and promote metastasis by facilitating PCDH9 ubiquitination and degradation,highlighting its role as a prognostic biomarker and a potential therapeutic target.展开更多
1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(inclu...1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(including Archean-Proterozoic migmatite,gneiss,schists and Pan-African “Older Granites”),Mesozoic alkaline ring complexes(“Younger Granites”) and sedimentary basins(Yang QD et al.,2023;Fig.1a).“Older Granites” are part of the Pan-African mobile belt;“Younger Granites” has significant peralkaline characteristics.“Younger Granites” has a wide distribution in the north-central region of Nigeria,including areas such as Kano,Jos-Bauchi,Mada,and Nasarawa,and the emplacement age gradually decreases from north to south from 213 Ma(Dutse complex) to 141 Ma(Afu complex)(Amuda AK et al.,2021).展开更多
Organic and pharmaceutical synthesis have traditionally relied on the stepwise transformation ofactivated functional groups to synthesize cyclic molecules.The design of valuable heterocyclic compounds,for instance,has...Organic and pharmaceutical synthesis have traditionally relied on the stepwise transformation ofactivated functional groups to synthesize cyclic molecules.The design of valuable heterocyclic compounds,for instance,has depended on multi-step routes such as polar or radical cyclization,cycloadditions,and the manipulation of various functional groups to achieve ring formation or connection[1,2].展开更多
RING protein 213(RNF213),the susceptibility gene for Moyamoya disease(MMD),possesses two active AAA+ATPase(ATPases Associated with diverse cellular Activities)modules,a RING,and RNF213-ZNFX1 finger(RZ finger)domains.S...RING protein 213(RNF213),the susceptibility gene for Moyamoya disease(MMD),possesses two active AAA+ATPase(ATPases Associated with diverse cellular Activities)modules,a RING,and RNF213-ZNFX1 finger(RZ finger)domains.Several RNF213 variants have been reported in MMD patients,including the p.R4810K variant(rs112735431),which is a founder polymorphism associated with MMDin EastAsia.To elucidate the function of RNF213 and its variant,we investigated the localization of RNF213 and the R4810K variant in this study.RNF213 induced circular hole structures near the nucleus,similar to lipid droplets(LDs),in U-2 OS cells.The holes decorated with tagged RNF213 protein were colocalized with mCherry-RAB5A and mCherry-peroxisome,but not mCherry-RAB9A and other organelles.RNF213 decorated the holes,and the structures were growing and changing to cylindrical objects,but not the R4810K variant efficiently.Furthermore,both AAA+ATPase modules and the ubiquitin ligase domain of RNF213 were required for the formation of the hole structures and cylindrical objects.These findings suggest that RNF213 activity may be involved in the formation of organelle-like structures,and this structure formation by RNF213 may be responsible for vascular functions.展开更多
随着人工智能大模型训练与推理业务的快速发展,智算中心面临算网协同调度的新挑战。为优化分布式智算Ring Allreduce业务的部署问题,首先,通过扩展传统波平面,开发了算力波平面技术,实现了算力与网络资源的一体化虚拟管理。然后,基于算...随着人工智能大模型训练与推理业务的快速发展,智算中心面临算网协同调度的新挑战。为优化分布式智算Ring Allreduce业务的部署问题,首先,通过扩展传统波平面,开发了算力波平面技术,实现了算力与网络资源的一体化虚拟管理。然后,基于算力波平面,提出了一种高效路由、波长、算力和时隙分配(routing,wavelength,computing power and time slot assignment,RWCTA)算法用于环规约(Ring Allreduce)业务部署。仿真结果表明,与传统基于波平面的部署算法相比,基于算力波平面的RWCTA算法能有效降低62.4%的总业务完成时间和54.5%的平均业务计算时间。展开更多
Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts o...Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species,likely driven by local climatic aridity,climate trends,edaphic conditions,and the climatic adaption of tree species.The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species.This study investigated radial growth trends,interannual growth variability,and growth-climate sensitivity of two dominant tree species,Pinus tabulaeformis(PT)and Pinus sylvestris var.mongolica(PS),across a broad climatic gradient with a variety of soil properties in temperate Northern China.Using a network of 83 tree ring chronologies(54 for PT and 29 for PS)from 1971 to 2010,we documented that both species maintained constant growth trends at wet sites,while both displayed rapid declines at dry sites.We reported the species-specific drivers of spatial heterogeneity in growth trends,interannual growth variability,and growth-climate relationships.Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships.However,climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship.Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth.Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables.Considering the continued climate warmingdrying trend in the future,both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.展开更多
In this study,we present a comprehensive evaluation of the magnetic field measurements from the Vector Field Magnetometer(VFM)aboard the recently launched Macao Science Satellite-1(MSS-1).One-year data from November 2...In this study,we present a comprehensive evaluation of the magnetic field measurements from the Vector Field Magnetometer(VFM)aboard the recently launched Macao Science Satellite-1(MSS-1).One-year data from November 2,2023,to November 1,2024,are considered.The MSS-1 flies with a low inclination(41°)and is designed to provide high-resolution magnetic field measurements,especially for monitoring the evolution of the South Atlantic Anomaly.Earlier studies confirmed the possibility of using MSS-1A data to model the Earth’s main magnetic field(e.g.,Jiang Y et al.,2024).Therefore,in this study we focus on the magnetic signatures related to the external field,which are primarily associated with magnetospheric and ionospheric currents.The global distributions of the magnetic residuals from MSS-1A show a pattern consistent with that derived from the European Space Agency’s Swarm A satellite.A statistical survey of the conjugated observations(withΔt<5 min andΔR<150 km)between the two satellites showed that the difference between their magnetic residuals is within±3 nanoteslas.By separating the magnetic residuals at the noon and midnight hours,we see that the MSS-1A data can effectively capture features of the magnetospheric and ionospheric currents,such as the magnetospheric ring current and ionospheric equatorial electrojet.Moreover,the magnetic residuals from MSS-1A show a diamagnetic effect caused by post-sunset equatorial plasma bubbles,which also suggests that the MSS-1A data have the potential to reveal the ionospheric structures.The comprehensive evaluations performed within this study demonstrate that the MSS-1A provides high-quality magnetic field data reaching the level of the Swarm satellite,which enables a deeper understanding of the modeling of Earth’s magnetic field as well as monitoring of the magnetic environment.展开更多
Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficien...The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.展开更多
基金"111 Project"Biomedical Textile Materials Science and Technology of China(No.B07024)Fundamental Research Funds for the Central Universities of China(No.12D10112)+2 种基金National Students Innovation Plans of China(No.X120711287,No.12T1010601)National Natural Science Foundation of China(No.81371648)Research Fund for the Doctoral Program of Higher Education of China(No.20100075110001)
文摘Stent-grafts were commercialized rapidly and gained a broad clinical acceptance over the past two decades. However,relatively more recent recognition of particular stent-graft design shortcomings have been identified which need to be addressed. It appears that various stent-graft designs may be more or less resistant to metal fatigue and /or fabric abrasions which can lead to type III and type IV endoleaks over the long term. Therefore,it is necessary to investigate the fatigue performance of the most common stentgraft designs: Z-stents and ringed stents,in a long-term in vitro fatigue simulation environment. This paper aimed to analyze nondestructively( gross observations) and destructively( fabric characteristics,mechanical and chemical properties) in order to put forward suggestions to improve the fabric and stent characteristics that may prevent type III and IV endoleaks. The fabric supported with ringed stent-grafts remained nearly completely intact after 168h. However, the fabric supported with Z-stents demonstrated significant damage. Fabric characteristics and tensile strength of the fibers did not present a significant difference between the control and fatigue simulated specimens. The crystallinity declined for both specimens. The fatigue performance of fabrics supported with ringed stents appears to be superior to that supported with Z-stents. The potential for a dynamic and destructive interaction between the apices of Z-stents which can lead to fraying and /or tearing of the graft fabric must be addressed in future designs.
基金This work was supported by The National Natural Science Foundation of China and also The State Science and Technology Commission of China under The National Key Project for Fundamental Research "Macromolecular Condensed State".
文摘The surface morphology of free-surface PCL ringed spherulites was investigated by using atomic force microscopy. The spherulites were obtained by crystallization of PCL/PVC blends of different compositions. It was found that the ringed spherulite exhibited regularly fluctuating rings on its surface. Compared with the bright-dark ring pattern of the spherulite under a polarizing microscope, it was proved that the optical characteristics of the ringed spherulite under polarizing microscope coincided with its surface characteristics. The bright rings in polarizing micrographs of the spherulite coincided with the convex rings on its surface, while the dark rings coincided with the concave rings.
文摘The author first introduces the notion of affine structures on a ringed space and then obtains several related properties.Affine structures on a ringed space,arising from complex analytical spaces of algebraic schemes,behave like differential structures on a smooth manifold.As one does for differential manifolds,pseudogroups of affine transformations are used to define affine atlases on a ringed space.An atlas on a space is said to be an affine structure if it is maximal.An affine structure is said to be admissible if there is a sheaf on the underlying space such that they are coincide on all affine charts,which are in deed affine open sets of a scheme.In a rigour manner,a scheme is defined to be a ringed space with a specified affine structure if the affine structures make a contribution to the cases such as analytical spaces of algebraic schemes.Particularly,by the whole of affine structures on a space,two necessary and sufficient conditions,that two spaces are homeomorphic and that two schemes are isomorphic,coming from the main theorems of the paper,are obtained respectively.A conclusion is drawn that the whole of affine structures on a space and a scheme,as local data,encode and reflect the global properties of the space and the scheme,respectively.
基金supported by the National Natural Science Foundation of China(U2544204,42172034,42330208,42288201)the China Geological Survey Project(Grant Nos.DD20243469,DD20221829).
文摘The wood anatomy of corystosperms is fundamentally consistent with that of gymnosperms,yet their growth ring boundaries share anatomical features with extant angiosperms.This transitional morphology strongly supports the interpretation of corystosperms as an evolutionary intermediate between gymnosperms and angiosperms.The first application of X-Ray fluorescence(XRF)chemical analysis to fossil wood taxa of Fengweioxylon yielded the above conclusion.By using growth ring analysis and ecological reconstructions,we suggest that corystosperms were large evergreen trees with leaf retention periods of three to five years.They likely thrived in warm summer environments where prolonged foliage retention provided adaptive benefits.
基金Project supported by the National Natural Science Foundation of China(Nos.52405095,12272089,and 92360305)the Guangdong Basic and Applied Basic Research Foundation of China(No.2023A1515110557)+4 种基金the Natural Science Foundation of Liaoning Province of China(No.2023-BSBA-102)the Open Fund of National Key Laboratory of Particle Transport and Separation Technology of China(No.WZKF-2024-6)the Open Project of Guangxi Key Laboratory of Automobile Components and Vehicle Technology of China(Nos.2024GKLACVTKF07 and 2024GKLACVTKF06)the Basic Research Projects of Liaoning Provincial Department of Education of China(No.JYTQN2023162)the Fundamental Research Funds for the Central Universities of China(No.N2403022)。
文摘The testing of large structures is limited by high costs and long cycles, making scaling methods an attractive solution. However, the scaling process of elastic rings introduces complexities in multi-parameter geometric distortions, leading to a diminution in the predictive accuracy of the distorted similitude. To address this challenge, this study formulates a novel set of scaling laws, tailored to account for the intricate geometric distortions associated with elastic rings. The proposed scaling laws are formulated based on the intrinsic deformation characteristics of elastic rings, rather than the traditional systemic governing equations. Numerical and experimental cases are conducted to assess the efficacy and precision of the proposed scaling laws, and the obtained results are compared with those achieved by traditional methods. The outcomes demonstrate that the scaling laws put forth by this study significantly enhance the predictive capabilities for deformations of elastic rings.
文摘Floating ring bearings are widely used in high-speed turbomachinery such as turbochargers and turbogenerators.Research-ers have recently explored various surface texturing strategies on the inner surface of floating rings to enhance bearing performance.In this study,the herring patterns are textured on the inner surface of the floating ring.This pattern is inspired by the secondary flight feathers of the Indian pigeon,which aid the bird in reducing viscous drag during flight.The result-ing Herringbone Textured Floating Ring Bearing(HTFRB)is investigated for its potential application in locomotive turbo-chargers.The HTFRB is numerically modeled using the Reynolds equation to evaluate the bearing's pressure distribution and static characteristics,including load-carrying capacity,power loss,and side leakage.Dynamic characteristics are determined by solving the zeroth-and first-order perturbed Reynolds equation.A Sobol sensitivity analysis is conducted to quantify the influence of groove parameters-helix angle,groove depth,groove width ratio,and number of grooves-on bearing performance metrics.An artificial intelligence-based optimization framework,integrating artificial neural networks and adaptive neuro-fuzzy inference systems,is developed to maximize load carrying capacity while minimiz-ing power loss,side leakage,and friction coefficient.The optimized texture parameters obtained from this framework are employed to validate the ANN model and evaluate the static and dynamic characteristics of the HTFRB.The dynamic coefficients of the HTFRB are further employed to evaluate the stability and robustness of the turbocharger rotor-HTFRB system.This study underscores the potential of combining bio-inspired texture design with numerical modeling and AI-based optimization to develop high-performance HTFRB.
基金supported by the NSFC Excellence Research Group Program on“Multiscale Problems in Nonlinear Mechanics”(Grant No.12588201)the National Natural Science Foundation of China(Grant Nos.12432011,12102246,12422208,12372219,12502258)。
文摘This study examines the dynamics of axis-offset collisions between two vortex rings using particle image velocimetry(PIV)measurements.At a fixed Reynolds number,the influence of axial separation on the flow evolution is systematically investigated.Finite-time Lyapunov exponent(FTLE)fields and combined vorticity-velocity analyses reveal three distinct interaction regimes.(1)In the collision and radial outflow regime(H/R_(ring)0.893,where H is the axial separation distance and R_(ring)is the ring radius),vortex rings undergo axial compression and generate strong radial outflows,with negligible material exchange between oppositely signed vortices.(2)In the collision and rebound regime(H/R_(ring)=1.786),the rings—bearing the same sign—experience a near-elastic rebound,leading to disintegration without reconnection.(3)In the merging-splitting and recovery regime(H/R_(ring)=2.679),the rings exhibit transient merging followed by splitting and coherence recovery,accompanied by significant material exchange.For even larger offsets(H/R_(ring)=3.572),interactions are negligible.These findings categorize axis-offset vortex ring interactions into three regimes based on flow behavior and yield insights relevant to enhanced mixing and heat dissipation in engineering applications.
基金financially supported by the National Natural Science Foundation of China (Nos.22375024,21975031,51933001,and 21734009)。
文摘The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impact of fluorination positions at side chains on NFREAs device performance remains scant.In this study,we introduce two isomeric NFREAs,designated as GA-2F-E and GA-2F,distinguished by their fluorination positions at the side chains.Both NFREAs share a thiophene[3,2-b]thiophene core,but their side chains differ:GA-2F-E features two(4-butylphenyl)-N-(4-fluorophenyl) amino groups,whereas GA-2F's side chains consist of bis(4-fluorophenyl)amino and bis(4-butylphenyl)amino groups attached to opposite sides of the core.To delve into the influence of fluorination positions on the optoelectronic properties,aggregation behavior,and overall efficiency of the acceptor molecules,a comprehensive investigation was conducted.The findings reveal that,despite similar photophysical properties and comparable absorption bandwidths,GA-2F-E,with fluorine atoms positioned on both sides of the molecular framework,demonstrates more compact π-π stacking,reduced bimolecular recombination,superior exciton transport,and a more balanced,higher mobility.As a result of these advantages,OSCs optimized with D18:GA-2F-E achieve a remarkable power conversion efficiency(PCE) of 16.45 %,surpassing the 15.83 %PCE of devices utilizing D18:GA-2F.This research underscores the potential of NFREAs in future applications and highlights the significance of fluorination positions in enhancing OSC performance,paving the way for the development of more efficient NFREAs.
基金Financial support from the National Natural Science Foundation of China(22375024,21975031,21734009,51933001,22109080,and 52173174)the Natural Science Foundation of Shandong Province(No.ZR2022YQ45)+2 种基金the Taishan Scholars Program(Nos.tstp20221121 and tsqnz20221134)The Beijing Natural Science Foundation(No.2244073)supported by State Key Laboratory of Bio-Fibers and Eco-Textiles(Qingdao University)(RZ2200002821)is acknowledged.
文摘A nonfused ring electron acceptor(NFREA),designated as TT-Ph-C6,has been synthesized with the aim of enhancing the power conversion efficiency(PCE)of organic solar cells(OSCs).By integrating asymmetric phenylalkylamino side groups,TT-Ph-C6 demonstrates excellent solubility and its crystal structure exhibits compact packing structures with a three-dimensional molecular stacking network.These structural attributes markedly promote exciton diffusion and charge carrier mobility,particularly advantageous for the fabrication of thick-film devices.TT-Ph-C6-based devices have attained a PCE of 18.01%at a film thickness of 100 nm,and even at a film thickness of 300 nm,the PCE remains at 14.64%,surpassing that of devices based on 2BTh-2F.These remarkable properties position TT-Ph-C6 as a highly promising NFREA material for boosting the efficiency of OSCs.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2024A1515012800)Chen Xiao-Ping Foundation for the Development of Science and Technology of Hubei Province(CXPJJH125001-2540).
文摘Objective:Ring finger protein 145(RNF145),an E3 ubiquitin ligase,is significantly upregulated in hepatocellular carcinoma(HCC).However,its role in HCC remains unknown.The study aimed to investigate the functions and underlying mechanisms of RNF145 in HCC.Methods:The role of RNF145 in HCC was investigated using data from The Cancer Genome Atlas(TCGA)and in vitro experimental assays.Its oncogenic functions were assessed using the transwell migration assay and the wound-healing assay.The molecular mechanism was explored through protein immunoprecipitation and western blot analyses.Data from public databases were analyzed to correlate RNF145 expression with clinicopathological features.Univariate and multivariate Cox analyses established RNF145 as an independent prognostic factor.Subsequently,a prognostic nomogram was constructed.Results:RNF145 was upregulated in HCC.The expression level of RNF145 in HCC showed significant correlations with histological grade,pathological stage,and vascular invasion.Functionally,knockdown of RNF145 effectively abolished the migratory and invasive capacities of HCC cells.This pro-metastatic effect is mediated through the RNF145-driven ubiquitination and subsequent degradation of protocadherin 9(PCDH9).Conclusion:Our findings confirm the significant upregulation of RNF145 in HCC and promote metastasis by facilitating PCDH9 ubiquitination and degradation,highlighting its role as a prognostic biomarker and a potential therapeutic target.
基金funded by the projects of Tianjin North China Geological Exploration Bureau (HK2023–B01,HK2022–B08)China Geological Survey (DD20230576,DD20201152)。
文摘1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(including Archean-Proterozoic migmatite,gneiss,schists and Pan-African “Older Granites”),Mesozoic alkaline ring complexes(“Younger Granites”) and sedimentary basins(Yang QD et al.,2023;Fig.1a).“Older Granites” are part of the Pan-African mobile belt;“Younger Granites” has significant peralkaline characteristics.“Younger Granites” has a wide distribution in the north-central region of Nigeria,including areas such as Kano,Jos-Bauchi,Mada,and Nasarawa,and the emplacement age gradually decreases from north to south from 213 Ma(Dutse complex) to 141 Ma(Afu complex)(Amuda AK et al.,2021).
基金supported by the MSIT(2022R1F1A106268,RS-2023-00213491,RS-2023-00219859,RS-2024-00405261,RS-2024-00409589,RS-2025-25460522,and RS-2025-00642970)Republic of Korea,the InnoCORE program of the Ministry of Science and ICT of Korea(N10250153 and 1.250022.01)the Creative Research Program and KAIST Cross-Generation Collaborative Lab Project.
文摘Organic and pharmaceutical synthesis have traditionally relied on the stepwise transformation ofactivated functional groups to synthesize cyclic molecules.The design of valuable heterocyclic compounds,for instance,has depended on multi-step routes such as polar or radical cyclization,cycloadditions,and the manipulation of various functional groups to achieve ring formation or connection[1,2].
基金supported by grants(#15611607)from the Ministry of Education,Culture,Sports,Science and Technology of Japan to T.H.
文摘RING protein 213(RNF213),the susceptibility gene for Moyamoya disease(MMD),possesses two active AAA+ATPase(ATPases Associated with diverse cellular Activities)modules,a RING,and RNF213-ZNFX1 finger(RZ finger)domains.Several RNF213 variants have been reported in MMD patients,including the p.R4810K variant(rs112735431),which is a founder polymorphism associated with MMDin EastAsia.To elucidate the function of RNF213 and its variant,we investigated the localization of RNF213 and the R4810K variant in this study.RNF213 induced circular hole structures near the nucleus,similar to lipid droplets(LDs),in U-2 OS cells.The holes decorated with tagged RNF213 protein were colocalized with mCherry-RAB5A and mCherry-peroxisome,but not mCherry-RAB9A and other organelles.RNF213 decorated the holes,and the structures were growing and changing to cylindrical objects,but not the R4810K variant efficiently.Furthermore,both AAA+ATPase modules and the ubiquitin ligase domain of RNF213 were required for the formation of the hole structures and cylindrical objects.These findings suggest that RNF213 activity may be involved in the formation of organelle-like structures,and this structure formation by RNF213 may be responsible for vascular functions.
文摘随着人工智能大模型训练与推理业务的快速发展,智算中心面临算网协同调度的新挑战。为优化分布式智算Ring Allreduce业务的部署问题,首先,通过扩展传统波平面,开发了算力波平面技术,实现了算力与网络资源的一体化虚拟管理。然后,基于算力波平面,提出了一种高效路由、波长、算力和时隙分配(routing,wavelength,computing power and time slot assignment,RWCTA)算法用于环规约(Ring Allreduce)业务部署。仿真结果表明,与传统基于波平面的部署算法相比,基于算力波平面的RWCTA算法能有效降低62.4%的总业务完成时间和54.5%的平均业务计算时间。
基金funded by the National Key Research and Development Plan of China(No.2022YFE0127900)the National Natural Science Foundation of China(Nos.32071558,32171559)+2 种基金the Natural Science Foundation Key Project of Inner Mongolia Autonomous Region,China(No.2023ZD23)the Hulunbuir Science and Technology Plan Project(No.SF2022001)the Fundamental Research Funds of CAF(CAFYBB2023ZA002).
文摘Increasing temperatures and severe droughts threaten forest vitality globally.Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species,likely driven by local climatic aridity,climate trends,edaphic conditions,and the climatic adaption of tree species.The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species.This study investigated radial growth trends,interannual growth variability,and growth-climate sensitivity of two dominant tree species,Pinus tabulaeformis(PT)and Pinus sylvestris var.mongolica(PS),across a broad climatic gradient with a variety of soil properties in temperate Northern China.Using a network of 83 tree ring chronologies(54 for PT and 29 for PS)from 1971 to 2010,we documented that both species maintained constant growth trends at wet sites,while both displayed rapid declines at dry sites.We reported the species-specific drivers of spatial heterogeneity in growth trends,interannual growth variability,and growth-climate relationships.Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships.However,climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship.Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth.Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables.Considering the continued climate warmingdrying trend in the future,both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.
基金supported by the National Natural Science Foundation of China(Grant Nos.42474200 and 42174186)Chao Xiong is supported by the Dragon 6 cooperation 2024-2028(Project No.95437).
文摘In this study,we present a comprehensive evaluation of the magnetic field measurements from the Vector Field Magnetometer(VFM)aboard the recently launched Macao Science Satellite-1(MSS-1).One-year data from November 2,2023,to November 1,2024,are considered.The MSS-1 flies with a low inclination(41°)and is designed to provide high-resolution magnetic field measurements,especially for monitoring the evolution of the South Atlantic Anomaly.Earlier studies confirmed the possibility of using MSS-1A data to model the Earth’s main magnetic field(e.g.,Jiang Y et al.,2024).Therefore,in this study we focus on the magnetic signatures related to the external field,which are primarily associated with magnetospheric and ionospheric currents.The global distributions of the magnetic residuals from MSS-1A show a pattern consistent with that derived from the European Space Agency’s Swarm A satellite.A statistical survey of the conjugated observations(withΔt<5 min andΔR<150 km)between the two satellites showed that the difference between their magnetic residuals is within±3 nanoteslas.By separating the magnetic residuals at the noon and midnight hours,we see that the MSS-1A data can effectively capture features of the magnetospheric and ionospheric currents,such as the magnetospheric ring current and ionospheric equatorial electrojet.Moreover,the magnetic residuals from MSS-1A show a diamagnetic effect caused by post-sunset equatorial plasma bubbles,which also suggests that the MSS-1A data have the potential to reveal the ionospheric structures.The comprehensive evaluations performed within this study demonstrate that the MSS-1A provides high-quality magnetic field data reaching the level of the Swarm satellite,which enables a deeper understanding of the modeling of Earth’s magnetic field as well as monitoring of the magnetic environment.
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
基金the National Natural Science Foundation of China(No.52275378)the National Key Laboratory for Precision Hot Processing of Metals(6142909200208)。
文摘The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.
