Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extrac...Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extraction velocity(v_(e))and extraction distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as v_(r) and v_(e) increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the v_(r),v_(e) and L were optimized and applied in the 63_(up) 08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver’s position increased by 71%.The dust concentration was reduced and the working environment had been improved effectively.展开更多
The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise int...The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise intensity than the wingless load.Due to the severe aerodynamic instability prior to separation,the head-up or head-down phenomena are more evident and the test accuracy significantly decreases.The high-precision computer fluid dynamics and aeroacoustic analysis are employed to explore the multifield coupling mechanism of a rocket sled with the winged payload in the wide speed range(Ma=0.5–2).The results show that as the incoming velocity increases,the cone angle of the shock wave of the rocket sled decreases,the shock pressure increases quickly,and the vortex between the slippers splits and gradually shrinks in size.The velocity of the rocket sled exerts little influence on the modal resonance frequency.The wing has a significant impact on aerodynamic noise,and as the sound pressure level rises,the propagation direction gradually shifts towards the rear and upper regions of the wing.展开更多
The study of capture mechanisms with high capture adaptability is the key to improving the efficiency of autonomous underwater vehicle(AUV)retrieval and release.This study aims to develop a capture mechanism for the l...The study of capture mechanisms with high capture adaptability is the key to improving the efficiency of autonomous underwater vehicle(AUV)retrieval and release.This study aims to develop a capture mechanism for the launch and recovery of AUV and elucidate its kinematic characteristics.Initially,based on the principles of deployment and retraction for AUV capture movements,a design scheme for a novel foldable and deployable capture mechanism is proposed.Subsequently,a detailed analysis of the Degrees of Freedom(DoFs)for enveloping and grasping movements is conducted according to screw theory.Additionally,the structural design of the actuation units for the capture mechanism is thoroughly discussed.Motion screw topology diagram is utilized to construct the kinematic model.On this basis,kinematic simulation verification of the capture mechanism is performed.The theoretical analysis revealed that the DoF for enveloping and grasping movements are 6 and 2,respectively.By appropriately configuring the actuation mechanism,enveloping and grasping movements can be achieved with a single actuation.The displacement and velocity curves of the capture mechanism were smooth,with no interference occurring.Vibration test results validate the reliability of the capture mechanism.The research work provides a valuable reference for the development of novel capture equipment for AUVs.展开更多
Unsteady aerodynamic characteristics at high angles of attack are of great importance to the design and development of advanced fighter aircraft, which are characterized by post-stall maneuverability with multiple Deg...Unsteady aerodynamic characteristics at high angles of attack are of great importance to the design and development of advanced fighter aircraft, which are characterized by post-stall maneuverability with multiple Degrees-of-Freedom(multi-DOF) and complex flow field structure.In this paper, a special kind of cable-driven parallel mechanism is firstly utilized as a new suspension method to conduct unsteady dynamic wind tunnel tests at high angles of attack, thereby providing experimental aerodynamic data. These tests include a wide range of multi-DOF coupled oscillatory motions with various amplitudes and frequencies. Then, for aerodynamic modeling and analysis, a novel data-driven Feature-Level Attention Recurrent neural network(FLAR) is proposed. This model incorporates a specially designed feature-level attention module that focuses on the state variables affecting the aerodynamic coefficients, thereby enhancing the physical interpretability of the aerodynamic model. Subsequently, spin maneuver simulations, using a mathematical model as the baseline, are conducted to validate the effectiveness of the FLAR. Finally, the results on wind tunnel data reveal that the FLAR accurately predicts aerodynamic coefficients, and observations through the visualization of attention scores identify the key state variables that affect the aerodynamic coefficients. It is concluded that the proposed FLAR enhances the interpretability of the aerodynamic model while achieving good prediction accuracy and generalization capability for multi-DOF coupling motion at high angles of attack.展开更多
Parallel mechanisms with fewer degrees of freedom that incorporate two or more SPR limbs have been widely adopted in industrial applications in recent years.However,notable theoretical gaps persist,particularly in the...Parallel mechanisms with fewer degrees of freedom that incorporate two or more SPR limbs have been widely adopted in industrial applications in recent years.However,notable theoretical gaps persist,particularly in the field of analytical solutions for forward kinematics.To address this,this paper proposes an innovative forward kinematics analysis method based on Conformal Geometric Algebra(CGA)for complex hybrid mechanisms formed by serial concatenation of such parallel mechanisms.The method efficiently represents geometric elements and their operational relationships by defining appropriate unknown parameters.It constructs fundamental geometric objects such as spheres and planes,derives vertex expressions through intersection and dual operations,and establishes univariate high-order equations via inner product operations,ultimately obtaining complete analytical solutions for the forward kinematics of hybrid mechanisms.Using the(2-SPR+RPS)+(3-SPR)serial-parallel hybrid mechanism as a validation case,three configuration tests implemented in Mathematica demonstrate that:for each configuration,the upper 3-SPR mechanism yields 15 mathematical solutions,while the lower 2-SPR+RPS mechanism yields 4 mathematical solutions.After geometric constraint filtering,a unique physically valid solution is obtained for each mechanism.SolidWorks simulations further verify the correctness and reliability of the model.This research provides a reliable analytical method for forward kinematics of hybrid mechanisms,holding significant implications for advancing their applications in high-precision scenarios.展开更多
The WSC proteins produced by Penicillium expansum play a crucial role in causing blue mold on pears.To analyze the role of the WSC1 gene in the pathogenic process of this fungal pathogen,we conducted transcriptomic an...The WSC proteins produced by Penicillium expansum play a crucial role in causing blue mold on pears.To analyze the role of the WSC1 gene in the pathogenic process of this fungal pathogen,we conducted transcriptomic analysis of a WSC1 knockout(ΔWSC1)strain.The knockout of WSC1 significantly altered the gene expression profile in P.expansum,particularly for genes involved in cell wall integrity,signaling,stress response,and toxin production.The differential expression of these genes might make theΔWSC1 strain more vulnerable to environmental stress,while reducing the toxin production capacity,ultimately leading to a decrease in the pathogenicity.The transcriptomic analysis revealed that the expression of genes related to stress response signals,defense mechanisms and oxidative stress management changed when pear fruits were infected with theΔWSC1 strain.These changes may trigger a cascade of responses in pear fruits.In addition,compared with those infected with the wild-type strain,pear fruits infected with theΔWSC1 strain exhibited up-regulated expression of genes related to defense and oxidative stress.This study clarifies how the WSC1 gene influences P.expansum’s ability to infect pear fruits and how pear fruits respond to the infection.展开更多
Polyethylene glycol(PEG)with different chains was used to modify epoxy asphalt.Molecular models of PEG⁃modified epoxy asphalt were developed using molecu⁃lar simulations(MS).The thermodynamic and mechanical properties...Polyethylene glycol(PEG)with different chains was used to modify epoxy asphalt.Molecular models of PEG⁃modified epoxy asphalt were developed using molecu⁃lar simulations(MS).The thermodynamic and mechanical properties of PEG⁃modified epoxy asphalt were analyzed,and its toughening mechanisms were explored.A method based on the Dijkstra algorithm was proposed to evaluate ep⁃oxy asphalt crosslinked networks.The results show that the introduction of PEG chains into epoxy asphalt can lower the glass transition temperature and enhance its toughness be⁃cause of the extended length of the PEG chains,which can in⁃crease the free volume and improve the mobility of the epoxy resin in the epoxy asphalt.The crosslinked network quantita⁃tive evaluation method based on the Dijkstra algorithm can ef⁃fectively evaluate the distribution of epoxy asphalt crosslink⁃ing bonds,providing further explanation of the toughening mechanism of PEG⁃modified epoxy asphalt.The feasibility of designing and screening epoxy asphalt materials by MS is verified,and a guide for toughening mechanism research of epoxy asphalt at the molecular level is provided.展开更多
Reconfigurable parallel mechanisms were first discovered in response to the growing demand for flexible and adaptive systems in various fields.Unlike traditional mechanisms,which are designed for specific tasks and ha...Reconfigurable parallel mechanisms were first discovered in response to the growing demand for flexible and adaptive systems in various fields.Unlike traditional mechanisms,which are designed for specific tasks and have fixed topology and mobility characteristics,a reconfigurable parallel mechanism can be adapted to different situations by changing its structure,motion,and function.This adaptability enables a single mechanism to perform a wide range of tasks,reducing the need for multiple dedicated systems.This paper presents a comprehensive review of reconfigurable parallel mechanisms.The characteristics of their designs,analyses of their properties,and challenges they face are reported.The beginning of this paper features an introduction of reconfigurable parallel mechanisms and their classification into different types.Methods for synthesizing reconfigurable parallel mechanisms are discussed.A performance evaluation index related to reconfigurability,workspace,singularity,stiffness,and dynamics,among other indices,is presented.This review covers the challenges faced in the creation of systematic design theories,unified performance analyses,evaluation index systems,and in the implementation of reconfigurable parallel mechanisms,such as the development of efficient control strategies and integration with other technologies.The paper concludes with a discussion of future research directions for reconfigurable parallel mechanisms.展开更多
Origami mechanisms are extensively employed in various engineering applications due to their exceptional folding performance and deformability.The key to designing origami mechanisms lies in the design of the creases....Origami mechanisms are extensively employed in various engineering applications due to their exceptional folding performance and deformability.The key to designing origami mechanisms lies in the design of the creases.The crease design is often derived from experience and inspiration,so it is crucial to have a systematic approach to crease design.In this paper,a novel synthesis approach based on graph theory is proposed,which effectively addresses the challenge of designing the creases in origami mechanisms.The essence of this method lies in the acquisition of the double symmetrical crease pattern through the directed graph product operation of two subgraphs.The crease pattern can be simplified by employing a technique that eliminates certain creases while preserving the non-isomorphism and symmetry of the pattern.An improved mixed-integer linear programming model is developed to achieve an automatic distribution of the peak_valley creases of the origami.The proposed method ultimately generates 12 unique double symmetrical crease patterns.The new method proposed in this paper,through systematic design,significantly improves the efficiency of mechanism design while opening up broad prospects for exploring new mechanism structures,thereby greatly expanding its application potential in cutting-edge fields such as aerospace engineering and intelligent robots.展开更多
In this work,mechanical properties,the tensile anisotropy,and deformation mechanisms during tensile testing of rolled Mg-6.3Gd-3Li-2Zn-0.5Al alloys(R2 and R4)were analyzed with Visco-Plastic Self-Consistent(VPSC)model...In this work,mechanical properties,the tensile anisotropy,and deformation mechanisms during tensile testing of rolled Mg-6.3Gd-3Li-2Zn-0.5Al alloys(R2 and R4)were analyzed with Visco-Plastic Self-Consistent(VPSC)model and material characterization techniques.The results showed that the mechanical properties of the rolled Mg-Gd-Li alloy displayed considerable anisotropy,with highest yield strength and tensile strength along the rolling direction(RD)measured at 272.3 MPa and 294.5 MPa,respectively.Conversely,the yield and tensile strength in the transverse direction(TD)were merely 214.7 MPa and 253.1 MPa,respectively.Furthermore,the anisotropy increased with the deformation.The VPSC models for rolled Mg-Gd-Li alloy in tensile deformation were constructed,respectively,by adjusting the hardening parameters.Pyramidal<c+a>slip,which dominated the deformation mechanisms of Mg-Gd-Li alloy,was calculated via VPSC model and observed in electron backscatter diffraction(EBSD)data.The stress-strain curves and pole figures generated from the VPSC model exhibited excellent agreement with experimental results.For the rolled Mg-Gd-Li alloy,the activation levels of basalslip along different tensile directions were the main cause of the anisotropy in yield strength.On the other hand,the activation levels of(10–12)twinning during deformation in various tensile orientations were primarily responsible for the anisotropy in tensile strength.展开更多
The “3·31” severe squall line event in eastern China was notable for its exceptional intensity and persistence,posing significant challenges to forecast accuracy. This study analyzed the maintenance stage of th...The “3·31” severe squall line event in eastern China was notable for its exceptional intensity and persistence,posing significant challenges to forecast accuracy. This study analyzed the maintenance stage of this event using highresolution convection-permitting numerical simulations, with a focus on vorticity budgets of the environmental flow, multiscale synoptic diagnostics, and Rotunno-Klemp-Weisman(RKW) theory. These analyses aimed to elucidate the mechanisms governing the morphological transition, the generation of associated convective gales, and the prolonged maintenance of the squall line event. The results show that the numerical simulation accurately reproduced the development and evolution of the squall line, particularly its location, with surface wind errors remaining within a reasonable range. The development of a mesoscale vortex modulated the dynamic and water vapor fields, providing favorable mesoscale environmental conditions for the organization and maintenance of the squall line. Vorticity budget analysis indicates that the divergence and tilting terms were the primary contributors to vorticity tendency. After the squall line entered Jiangxi Province, it exhibited a sharper leading edge and enhanced upward motion. Dry intrusion from the mid-toupper troposphere led to rapid downward momentum transfer at the meso-γ scale, thereby generating convective gales. In addition, the enhancement of the rear-inflow jet(RIJ) was related to the pressure difference between the interior and exterior of system, which resulted from the phase change of condensate within tilted updrafts. The RIJ was orthogonal to the squall line, causing it to transform from a linear into a bowing shape. Diagnosis based on the RKW theory underscore the important roles in both low-level and deep vertical wind shear in maintenaning the squall line. The ratios of the cold pool propagation velocity to the vertical wind shear were close to 1, which balanced with the ambient horizontal vorticity that allowed the convection to remain upright, thus sustaining the squall line's intensity for an extended period. In summary, the squall line event was sustained by a favorable environment created by the environmental vortex. The dry intrusion from the mid-to-upper troposphere and intensified RIJ resulted in the severe convective winds, while the balance between cold pool and ambient vertical wind shear promoted the system's prolonged maintenance. These findings provide an effective reference for the short-range forecasting of squall lines throughout their lifecycle.展开更多
Pu-erh tea,a traditional Chinese beverage,performs an anti-obesity function,but the correlation between its components and efficacy remains unknown.Here,we screened two Pu-erh teas with significant anti-obesity effica...Pu-erh tea,a traditional Chinese beverage,performs an anti-obesity function,but the correlation between its components and efficacy remains unknown.Here,we screened two Pu-erh teas with significant anti-obesity efficacies from 11 teas.In vitro experiments revealed that lipid accumulation in L02 cells and lipid synthesis in 3T3-L1 cells were significantly better inhibited by Tea-B than Tea-A.Further in vivo experiments using model mice revealed that the differences in chemical components generated two pathways in the anti-obesity efficacy and mechanism of Pu-erh teas.Tea-A changes the histomorphology of brown adipose tissue(BAT)and increases the abundance of Coriobacteriaceae_UCG_002 and cyclic AMP in guts through high chemical contents of cyclopentasiloxane,decamethyl,tridecane and 1,2,3-trimethoxybenzene,eventually increasing BAT activation and fat browning gene expression;the high content of hexadecane and 1,2-dimethoxybenzene in Tea-B reduces white adipose tissue(WAT)accumulation and the process of fatty liver,increases the abundance of Odoribacter and sphinganine 1-phosphate,inhibits the expression of lipid synthesis and transport genes.These mechanistic findings on the association of the representative bioactive components in Pu-erh teas with the anti-obesity phenotypes,gut microbes,gut metabolite structure and anti-obesity pathways,which were obtained for the first time,provide foundations for developing functional Pu-erh tea.展开更多
Acetone is a common volatile organic compound that can cause harm to human health when inhaled in small amounts.Therefore,the development of fast response and low detection limit acetone sensors becomes crucial.In thi...Acetone is a common volatile organic compound that can cause harm to human health when inhaled in small amounts.Therefore,the development of fast response and low detection limit acetone sensors becomes crucial.In this study,a core-shell spherical TiO_(2) sensor with a rich pore structure was designed.This sensor exhibited excellent sensing properties,including higher responsiveness(100 ppm acetone,R_(a)/R_(g)=80),lower detection limit(10 ppb)and short response time(8 s).The problem is that the sensing mechanism between TiO_(2) and acetone is not thoroughly analyzed.To gain further insight,the interaction process of TiO_(2) core-shell spheres and acetone under varying oxygen content environments was investigated by dynamic testing,X-ray photoelectron spectroscopy,in-situ Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry.The research results show that acetone not only adsorbs on the surface of the material and reacts with adsorbed oxygen,but also undergoes catalytic oxidation reaction with TiO_(2) core-shell spheres.Significantly,in high oxygen content environments,acetone undergoes oxidation to form intermediates such as acids and anhydrides that are difficult to desorpt on the surface of the material,thus prolonging the recovery time of the sensor.The discovery of this sensing process will provide some guidance for the design of acetone sensing materials in the future.Meanwhile,this also imparts valuable references and insights for the investigation of the mechanism and application of other sensitive metal oxide materials.展开更多
The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were ...The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were used to investigate the effects of temperature(700–1100℃),CO_(2)(3%–10%),and H_(2)O(1%–9%)concentrations on CH_(4) conversion efficiency.Results indicate that CH_(4) conversion exceeds 90%at temperatures above 1000℃,with CO_(2) and H_(2)O concentrations at 9%and 5%,respectively.During the reforming process,introducing CO_(2) provides additional oxygen,facilitating the oxidation of CH_(4),while H_(2)O enhances H_(2) production through the steam reforming pathway.Experimental findings reveal a CH_(4) conversion of 85.83%with a H_(2)/CO ratio of 5.44 at 1050℃.In addition,an optimal H_(2)O concentration of 6%yields the highest CH_(4) conversion of 84.24%,while CO_(2) exhibits minimal effects on promoting the reforming process.Increasing the metallization rate of pellets from 43%to 92%significantly enhances CH_(4) reforming.This is mainly due to the fact that metallized iron is vital in promoting CH_(4) dissociation and improving syngas yield by providing active sites for the redox cycle of CO_(2) and H_(2)O.展开更多
With policy support for carbon capture,utilization,and storage(CCUS),an integrated approach that combines energy storage fracturing,CO_(2)-enhanced oil recovery(EOR),and storage emerges as a promising direction for th...With policy support for carbon capture,utilization,and storage(CCUS),an integrated approach that combines energy storage fracturing,CO_(2)-enhanced oil recovery(EOR),and storage emerges as a promising direction for the shale oil industry.The process of energy storage fracturing induces significant changes in the pressure and saturation of the medium.However,conventional simulations often overlook the effects of fracturing and shut-in operations on the seepage field and production performance.Furthermore,fractured shale reservoirs exhibit complex non-Darcy flow characteristics due to intricate pore structures and multi-scale porous media.A comprehensive understanding of flow mechanisms is essential for effective reservoir development and CO_(2) storage.This study establishes a multi-component simulation model that encompasses the life-cycle of fracturing,shut-in,production,and CO_(2) huff-n-puff processes,thereby ensuring the continuity of the seepage field.The model accounts for the effect of nano-confinement on phase behavior by modifying the equation of state.Furthermore,the flux term is adjusted to incorporate Maxwell–Stefan diffusion,pre-/post-Darcy flow,and stress sensitivity.The embedded discrete fracture model(EDFM)is employed to simulate multiphase flow within multi-scale media,and the results from the validation model align satisfactorily with those derived from ECLIPSE.Mechanism analysis indicates that the interaction of multiple mechanisms significantly influences both production and storage performance.Under the multi-mechanism coupling,the cumulative oil production increased by 12.01%,while the utilization and storage factors increased by 62.93%and 8.93%,respectively.The role of molecular diffusion in shale oil reservoirs may be overstated,contributing only a 0.26% enhancement in oil production.Simulation results show that the energy storage fracturing strategy can increase oil production and net present value by 12.47%and 15.07%,respectively.Sensitivity analysis indicates that the CO_(2) injection rate is the main factor affecting the recovery factor,followed by CO_(2) injection time and the number of cycles,with fracturing fluid volume having the least impact.This study develops a multi-process,multi-mechanism simulation framework for multi-scale shale oil reservoirs.This framework provides a robust evaluation system for CCUS-EOR,facilitating informed decision-making in fracturing stimulation,development planning,and parameter optimization.展开更多
Underwater Gliders(UGs)have emerged as vital instruments in marine research,offering distinct advantages including low operational costs,extended range capabilities,and superior durability.Traditional UGs,however,face...Underwater Gliders(UGs)have emerged as vital instruments in marine research,offering distinct advantages including low operational costs,extended range capabilities,and superior durability.Traditional UGs,however,face limitations due to their substantial size,weight,cost,and deployment complexity.Moreover,the conventional oil pump method for buoyancy adjustment exhibits slow response times,resulting in increased unsteady gliding depth ratios.These constraints limit their application in shallow water environments such as ports,coastal waters,and inland water bodies.This paper presents the TL-200,a small-sized underwater glider that incorporates an integrated buoyancy-driven and attitude adjustment mechanism.Through the implementation of an innovative buoyancy drive unit,the TL-200 achieves enhanced buoyancy regulation response while maintaining a simplified structure compared to conventional gliders.A dynamic model for the TL-200 was developed and validated through comparative analysis of numerical results and experimental data.Utilizing this dynamic model,motion simulations were conducted to examine the influence of metacentric height on motion parameters.Additionally,the study evaluated the gliding efficiency and energy consumption of the TL-200 under varying buoyancy adjustments.The findings demonstrate the effectiveness of this small-sized underwater glider's integrated buoyancy-driven and attitude adjustment mechanism.展开更多
Background:Diabetic foot,a severe complication of diabetes,is characterized by chronic refractory wounds.Sanhuang Oil,a topical herbal formula,demonstrates significant therapeutic effects including antibacterial,anti-...Background:Diabetic foot,a severe complication of diabetes,is characterized by chronic refractory wounds.Sanhuang Oil,a topical herbal formula,demonstrates significant therapeutic effects including antibacterial,anti-inflammatory,and immunomodulatory activities.However,its active constituents and mechanisms of action against diabetic foot remain to be elucidated.Methods:In this study,the chemical constituents of Sanhuang Oil were identified using UPLC-QE-Orbitrap-MS.Subsequently,the mechanism by which Sanhuang Oil promotes diabetic foot ulcer healing was predicted by integrating network pharmacology and molecular docking.Additionally,diabetic mouse model was established in ICR mice using a combination of a high-fat diet(HFD)and streptozotocin(STZ)chemical induction.A full-thickness skin defect was created on the dorsum of the mice.Wound healing and the healing rate were observed following Sanhuang Oil intervention.The mechanism underlying Sanhuang Oil’s promotion of diabetic ulcer healing was further investigated using transcriptomics and histopathological examination(H&E staining).Results:A total of 97 active ingredients were identified from Sanhuang Oil.Network pharmacology analysis predicted 543 common targets,and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis identified 203 relevant pathways.Molecular docking further confirmed high binding affinity(binding energy≤−5.0 kcal/mol)between specific active components in Sanhuang Oil(e.g.,coptisine,phellodendrine,baicalein)and key targets associated with diabetic foot ulcers(e.g.,EGFR,AKT1,STAT3).In vivo experimental results demonstrated that the wound healing rate was significantly higher in Sanhuang Oil-treated groups compared to the model group(P<0.001).HE staining revealed that the high-dose Sanhuang Oil group exhibited more pronounced epithelial tissue coverage over the wound,reduced inflammatory cell infiltration,and increased collagen deposition and fibroblast proliferation.transcriptomic analysis identified Pdk4,Ttn,Csrp3,Actn2,Myoz2,Tnnc2,Myod1,Myog,Myot,and Myf6 as key regulatory proteins involved in promoting wound healing.Conclusion:Sanhuang Oil promotes wound healing in diabetic ulcer mice,potentially by mitigating inflammation and regulating key targets such as Pdk4 to enhance fibroblast function.These findings provide novel insights into the multi-target,multi-pathway mechanism of Sanhuang Oil for treating diabetic foot ulcers.展开更多
The micro-area characterization experiments like scanning Kelvin probe force microscope(SKPFM)and Kernel average misorientation have the defects of complex sample preparation and occasional errors in test results,whic...The micro-area characterization experiments like scanning Kelvin probe force microscope(SKPFM)and Kernel average misorientation have the defects of complex sample preparation and occasional errors in test results,which makes it impossible to accurately and quickly analyze the pitting behavior induced by inclusions in some cases,prompting attempts to turn to simulation calculation research.The method of calculating band structure and work function can be used to replace current-sensing atomic force microscopy and SKPFM to detect the potential and conductivity of the sample.The band structure results show that Al_(2)O_(3) inclusion is an insulator and non-conductive,and it will not form galvanic corrosion with the matrix.Al_(2)O_(3) inclusion does not dissolve because its work function is higher than that of the matrix.Moreover,the stress concentration of the matrix around the inclusion can be characterized by first-principles calculation coupled with finite element simulation.The results show that the stress concentration degree of the matrix around Al_(2)O_(3) inclusion is serious,and the galvanic corrosion is formed between the high and the low stress concentration areas,which can be used to explain the reason of the pitting induced by Al_(2)O_(3) inclusions.展开更多
The contact characteristics between cycloidal gear teeth and pinwheel teeth significantly impact the operational performance of cycloidal pinwheel mechanisms.Current research methods tend to rely primarily on theoreti...The contact characteristics between cycloidal gear teeth and pinwheel teeth significantly impact the operational performance of cycloidal pinwheel mechanisms.Current research methods tend to rely primarily on theoretical calculations,with limited use of experimental methods for detecting dynamic contact properties.We propose a novel method for testing the dynamic contact characteristics of cycloidal pinwheel mechanisms.By combining Hertzian contact theory and contact strength theory,we establish a force and meshing stiffness model for the cycloidal and pinwheel gears,and determine the maximum contact stress and variations in pinwheel gear force and meshing stiffness.Based on the principle of photoelasticity,we built a testing platform for the cycloidal pinwheel mechanism to assess its contact characteristics.This platform provides the stress distribution of the cycloidal pinwheel mechanism and allows us to deduce key parameters such as the number of meshing teeth and the meshing interval.This study provides an experimental method for investigating the contact characteristics of cycloidal pinwheel mechanisms.展开更多
Teaching quality is the core guarantee for universities to achieve their talent cultivation goals,and teaching supervision,as an important means of monitoring teaching quality,runs through the entire process of teachi...Teaching quality is the core guarantee for universities to achieve their talent cultivation goals,and teaching supervision,as an important means of monitoring teaching quality,runs through the entire process of teaching management.Based on the teaching quality report of School A at University Z for the autumn semester of 2024,this paper systematically analyzes the current situation,problems,and causes of the teaching supervision mechanism through multi-dimensional data analysis of expert classroom observation,peer evaluation,and classroom feedback.On this basis,combined with the application prospects of artificial intelligence technology,it proposes paths to optimize the teaching supervision mechanism,including improving the classroom observation feedback mechanism,increasing supervision coverage,and strengthening the linkage between feedback and teaching reform,providing practical experience and theoretical support for improving teaching quality in universities.展开更多
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2020QE124,ZR2023ME031 and ZR2023ME012)Innovation Achievement Cultivation Project of Qingdao University of Technology(CLZ2022-002)National Natural Science Foundation of China(52404222 and 52374209).
文摘Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(v_(r)),axial extraction velocity(v_(e))and extraction distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as v_(r) and v_(e) increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the v_(r),v_(e) and L were optimized and applied in the 63_(up) 08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver’s position increased by 71%.The dust concentration was reduced and the working environment had been improved effectively.
基金supported by the National Natural Science Foundation of China(No.12104047)。
文摘The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise intensity than the wingless load.Due to the severe aerodynamic instability prior to separation,the head-up or head-down phenomena are more evident and the test accuracy significantly decreases.The high-precision computer fluid dynamics and aeroacoustic analysis are employed to explore the multifield coupling mechanism of a rocket sled with the winged payload in the wide speed range(Ma=0.5–2).The results show that as the incoming velocity increases,the cone angle of the shock wave of the rocket sled decreases,the shock pressure increases quickly,and the vortex between the slippers splits and gradually shrinks in size.The velocity of the rocket sled exerts little influence on the modal resonance frequency.The wing has a significant impact on aerodynamic noise,and as the sound pressure level rises,the propagation direction gradually shifts towards the rear and upper regions of the wing.
基金Supported by Jiangsu Provincial Natural Science Foundation(Grant No.BK20220649)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.23KJB460010)+2 种基金Provincial Key Laboratory of High-end Deepsea Machinery Equipment(Grant Nos.SYH2024003 and SYH2025001)the Jiangsu Provincial Key R&D Project(Grant No.BE2022062)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.SJCX25_2526).
文摘The study of capture mechanisms with high capture adaptability is the key to improving the efficiency of autonomous underwater vehicle(AUV)retrieval and release.This study aims to develop a capture mechanism for the launch and recovery of AUV and elucidate its kinematic characteristics.Initially,based on the principles of deployment and retraction for AUV capture movements,a design scheme for a novel foldable and deployable capture mechanism is proposed.Subsequently,a detailed analysis of the Degrees of Freedom(DoFs)for enveloping and grasping movements is conducted according to screw theory.Additionally,the structural design of the actuation units for the capture mechanism is thoroughly discussed.Motion screw topology diagram is utilized to construct the kinematic model.On this basis,kinematic simulation verification of the capture mechanism is performed.The theoretical analysis revealed that the DoF for enveloping and grasping movements are 6 and 2,respectively.By appropriately configuring the actuation mechanism,enveloping and grasping movements can be achieved with a single actuation.The displacement and velocity curves of the capture mechanism were smooth,with no interference occurring.Vibration test results validate the reliability of the capture mechanism.The research work provides a valuable reference for the development of novel capture equipment for AUVs.
基金supported by the National Natural Science Foundation of China(Nos.12172315,12072304,11702232)the Fujian Provincial Natural Science Foundation,China(No.2021J01050)the Aeronautical Science Foundation of China(No.20220013068002).
文摘Unsteady aerodynamic characteristics at high angles of attack are of great importance to the design and development of advanced fighter aircraft, which are characterized by post-stall maneuverability with multiple Degrees-of-Freedom(multi-DOF) and complex flow field structure.In this paper, a special kind of cable-driven parallel mechanism is firstly utilized as a new suspension method to conduct unsteady dynamic wind tunnel tests at high angles of attack, thereby providing experimental aerodynamic data. These tests include a wide range of multi-DOF coupled oscillatory motions with various amplitudes and frequencies. Then, for aerodynamic modeling and analysis, a novel data-driven Feature-Level Attention Recurrent neural network(FLAR) is proposed. This model incorporates a specially designed feature-level attention module that focuses on the state variables affecting the aerodynamic coefficients, thereby enhancing the physical interpretability of the aerodynamic model. Subsequently, spin maneuver simulations, using a mathematical model as the baseline, are conducted to validate the effectiveness of the FLAR. Finally, the results on wind tunnel data reveal that the FLAR accurately predicts aerodynamic coefficients, and observations through the visualization of attention scores identify the key state variables that affect the aerodynamic coefficients. It is concluded that the proposed FLAR enhances the interpretability of the aerodynamic model while achieving good prediction accuracy and generalization capability for multi-DOF coupling motion at high angles of attack.
基金Supported by Hebei Provincial Natural Science Foundation(Grant No.F2024202052)National Natural Science Foundation of China(Grant No.52175019)+3 种基金Beijing Municipal Natural Science Foundation(Grant No.L222038)Beijing Nova Programme Interdisciplinary Cooperation Project(Grant No.20240484699)Joint Funds of Industry-University-Research of Shanghai Academy of Spaceflight Technology(Grant No.SAST2022-017)Beijing Municipal Key Laboratory of Space-ground Interconnection and Convergence of China and Key Laboratory of IoT Monitoring and Early Warning,Ministry of Emergency Management。
文摘Parallel mechanisms with fewer degrees of freedom that incorporate two or more SPR limbs have been widely adopted in industrial applications in recent years.However,notable theoretical gaps persist,particularly in the field of analytical solutions for forward kinematics.To address this,this paper proposes an innovative forward kinematics analysis method based on Conformal Geometric Algebra(CGA)for complex hybrid mechanisms formed by serial concatenation of such parallel mechanisms.The method efficiently represents geometric elements and their operational relationships by defining appropriate unknown parameters.It constructs fundamental geometric objects such as spheres and planes,derives vertex expressions through intersection and dual operations,and establishes univariate high-order equations via inner product operations,ultimately obtaining complete analytical solutions for the forward kinematics of hybrid mechanisms.Using the(2-SPR+RPS)+(3-SPR)serial-parallel hybrid mechanism as a validation case,three configuration tests implemented in Mathematica demonstrate that:for each configuration,the upper 3-SPR mechanism yields 15 mathematical solutions,while the lower 2-SPR+RPS mechanism yields 4 mathematical solutions.After geometric constraint filtering,a unique physically valid solution is obtained for each mechanism.SolidWorks simulations further verify the correctness and reliability of the model.This research provides a reliable analytical method for forward kinematics of hybrid mechanisms,holding significant implications for advancing their applications in high-precision scenarios.
文摘The WSC proteins produced by Penicillium expansum play a crucial role in causing blue mold on pears.To analyze the role of the WSC1 gene in the pathogenic process of this fungal pathogen,we conducted transcriptomic analysis of a WSC1 knockout(ΔWSC1)strain.The knockout of WSC1 significantly altered the gene expression profile in P.expansum,particularly for genes involved in cell wall integrity,signaling,stress response,and toxin production.The differential expression of these genes might make theΔWSC1 strain more vulnerable to environmental stress,while reducing the toxin production capacity,ultimately leading to a decrease in the pathogenicity.The transcriptomic analysis revealed that the expression of genes related to stress response signals,defense mechanisms and oxidative stress management changed when pear fruits were infected with theΔWSC1 strain.These changes may trigger a cascade of responses in pear fruits.In addition,compared with those infected with the wild-type strain,pear fruits infected with theΔWSC1 strain exhibited up-regulated expression of genes related to defense and oxidative stress.This study clarifies how the WSC1 gene influences P.expansum’s ability to infect pear fruits and how pear fruits respond to the infection.
基金The Major Science and Technology Project of Nan⁃jing(No.202209012)the Postgraduate Research and Practice Innova⁃tion Program of Jiangsu Province(No.KYCX22⁃0277).
文摘Polyethylene glycol(PEG)with different chains was used to modify epoxy asphalt.Molecular models of PEG⁃modified epoxy asphalt were developed using molecu⁃lar simulations(MS).The thermodynamic and mechanical properties of PEG⁃modified epoxy asphalt were analyzed,and its toughening mechanisms were explored.A method based on the Dijkstra algorithm was proposed to evaluate ep⁃oxy asphalt crosslinked networks.The results show that the introduction of PEG chains into epoxy asphalt can lower the glass transition temperature and enhance its toughness be⁃cause of the extended length of the PEG chains,which can in⁃crease the free volume and improve the mobility of the epoxy resin in the epoxy asphalt.The crosslinked network quantita⁃tive evaluation method based on the Dijkstra algorithm can ef⁃fectively evaluate the distribution of epoxy asphalt crosslink⁃ing bonds,providing further explanation of the toughening mechanism of PEG⁃modified epoxy asphalt.The feasibility of designing and screening epoxy asphalt materials by MS is verified,and a guide for toughening mechanism research of epoxy asphalt at the molecular level is provided.
基金the financial support from the Research Institute for Artificial Intelligence of Things(RIAIoT)the Research Institute for Advanced Manufacturing(RIAM)+1 种基金the Research Institute for Intelligent Wearable Systems(RI-IWEAR)the Research Centre of Textiles for Future Fashion(RCTFF)at the Hong Kong Polytechnic University。
文摘Reconfigurable parallel mechanisms were first discovered in response to the growing demand for flexible and adaptive systems in various fields.Unlike traditional mechanisms,which are designed for specific tasks and have fixed topology and mobility characteristics,a reconfigurable parallel mechanism can be adapted to different situations by changing its structure,motion,and function.This adaptability enables a single mechanism to perform a wide range of tasks,reducing the need for multiple dedicated systems.This paper presents a comprehensive review of reconfigurable parallel mechanisms.The characteristics of their designs,analyses of their properties,and challenges they face are reported.The beginning of this paper features an introduction of reconfigurable parallel mechanisms and their classification into different types.Methods for synthesizing reconfigurable parallel mechanisms are discussed.A performance evaluation index related to reconfigurability,workspace,singularity,stiffness,and dynamics,among other indices,is presented.This review covers the challenges faced in the creation of systematic design theories,unified performance analyses,evaluation index systems,and in the implementation of reconfigurable parallel mechanisms,such as the development of efficient control strategies and integration with other technologies.The paper concludes with a discussion of future research directions for reconfigurable parallel mechanisms.
基金Supported by National Natural Science Foundation of China(Grant Nos.52375028,52205040)Hebei Provincial Natural Science Foundation(Grant Nos.E2024203052,E2024203105)Science and Technology Project of Hebei Education Department(Grant No.QN2023206).
文摘Origami mechanisms are extensively employed in various engineering applications due to their exceptional folding performance and deformability.The key to designing origami mechanisms lies in the design of the creases.The crease design is often derived from experience and inspiration,so it is crucial to have a systematic approach to crease design.In this paper,a novel synthesis approach based on graph theory is proposed,which effectively addresses the challenge of designing the creases in origami mechanisms.The essence of this method lies in the acquisition of the double symmetrical crease pattern through the directed graph product operation of two subgraphs.The crease pattern can be simplified by employing a technique that eliminates certain creases while preserving the non-isomorphism and symmetry of the pattern.An improved mixed-integer linear programming model is developed to achieve an automatic distribution of the peak_valley creases of the origami.The proposed method ultimately generates 12 unique double symmetrical crease patterns.The new method proposed in this paper,through systematic design,significantly improves the efficiency of mechanism design while opening up broad prospects for exploring new mechanism structures,thereby greatly expanding its application potential in cutting-edge fields such as aerospace engineering and intelligent robots.
基金the financial support provided by Key Research and Development Program of Heilongjiang(Grant No.2022ZX01A01)Natural Science Found of Heilongjiang Province(LH2022E080).
文摘In this work,mechanical properties,the tensile anisotropy,and deformation mechanisms during tensile testing of rolled Mg-6.3Gd-3Li-2Zn-0.5Al alloys(R2 and R4)were analyzed with Visco-Plastic Self-Consistent(VPSC)model and material characterization techniques.The results showed that the mechanical properties of the rolled Mg-Gd-Li alloy displayed considerable anisotropy,with highest yield strength and tensile strength along the rolling direction(RD)measured at 272.3 MPa and 294.5 MPa,respectively.Conversely,the yield and tensile strength in the transverse direction(TD)were merely 214.7 MPa and 253.1 MPa,respectively.Furthermore,the anisotropy increased with the deformation.The VPSC models for rolled Mg-Gd-Li alloy in tensile deformation were constructed,respectively,by adjusting the hardening parameters.Pyramidal<c+a>slip,which dominated the deformation mechanisms of Mg-Gd-Li alloy,was calculated via VPSC model and observed in electron backscatter diffraction(EBSD)data.The stress-strain curves and pole figures generated from the VPSC model exhibited excellent agreement with experimental results.For the rolled Mg-Gd-Li alloy,the activation levels of basalslip along different tensile directions were the main cause of the anisotropy in yield strength.On the other hand,the activation levels of(10–12)twinning during deformation in various tensile orientations were primarily responsible for the anisotropy in tensile strength.
基金Jiangxi Meteorological Bureau Project (JXCX202304,JX2024Y01)Geological Disaster Prevention and Control Project of Jiangxi Provincial Department of Natural Resources(B360000030004)+1 种基金Key Research and Development Project of Jiangxi Province (20243BBH81005)Weather Review Project of China Meteorological Administration (FPZJ2025-066)。
文摘The “3·31” severe squall line event in eastern China was notable for its exceptional intensity and persistence,posing significant challenges to forecast accuracy. This study analyzed the maintenance stage of this event using highresolution convection-permitting numerical simulations, with a focus on vorticity budgets of the environmental flow, multiscale synoptic diagnostics, and Rotunno-Klemp-Weisman(RKW) theory. These analyses aimed to elucidate the mechanisms governing the morphological transition, the generation of associated convective gales, and the prolonged maintenance of the squall line event. The results show that the numerical simulation accurately reproduced the development and evolution of the squall line, particularly its location, with surface wind errors remaining within a reasonable range. The development of a mesoscale vortex modulated the dynamic and water vapor fields, providing favorable mesoscale environmental conditions for the organization and maintenance of the squall line. Vorticity budget analysis indicates that the divergence and tilting terms were the primary contributors to vorticity tendency. After the squall line entered Jiangxi Province, it exhibited a sharper leading edge and enhanced upward motion. Dry intrusion from the mid-toupper troposphere led to rapid downward momentum transfer at the meso-γ scale, thereby generating convective gales. In addition, the enhancement of the rear-inflow jet(RIJ) was related to the pressure difference between the interior and exterior of system, which resulted from the phase change of condensate within tilted updrafts. The RIJ was orthogonal to the squall line, causing it to transform from a linear into a bowing shape. Diagnosis based on the RKW theory underscore the important roles in both low-level and deep vertical wind shear in maintenaning the squall line. The ratios of the cold pool propagation velocity to the vertical wind shear were close to 1, which balanced with the ambient horizontal vorticity that allowed the convection to remain upright, thus sustaining the squall line's intensity for an extended period. In summary, the squall line event was sustained by a favorable environment created by the environmental vortex. The dry intrusion from the mid-to-upper troposphere and intensified RIJ resulted in the severe convective winds, while the balance between cold pool and ambient vertical wind shear promoted the system's prolonged maintenance. These findings provide an effective reference for the short-range forecasting of squall lines throughout their lifecycle.
基金The financial support received from the Shenzhen Science and Technology Innovation Commission(KCXFZ20201221173207022,WDZC20200821141349001)Shenzhen Bay Laboratory Startup Fund(21310041,S234602003)。
文摘Pu-erh tea,a traditional Chinese beverage,performs an anti-obesity function,but the correlation between its components and efficacy remains unknown.Here,we screened two Pu-erh teas with significant anti-obesity efficacies from 11 teas.In vitro experiments revealed that lipid accumulation in L02 cells and lipid synthesis in 3T3-L1 cells were significantly better inhibited by Tea-B than Tea-A.Further in vivo experiments using model mice revealed that the differences in chemical components generated two pathways in the anti-obesity efficacy and mechanism of Pu-erh teas.Tea-A changes the histomorphology of brown adipose tissue(BAT)and increases the abundance of Coriobacteriaceae_UCG_002 and cyclic AMP in guts through high chemical contents of cyclopentasiloxane,decamethyl,tridecane and 1,2,3-trimethoxybenzene,eventually increasing BAT activation and fat browning gene expression;the high content of hexadecane and 1,2-dimethoxybenzene in Tea-B reduces white adipose tissue(WAT)accumulation and the process of fatty liver,increases the abundance of Odoribacter and sphinganine 1-phosphate,inhibits the expression of lipid synthesis and transport genes.These mechanistic findings on the association of the representative bioactive components in Pu-erh teas with the anti-obesity phenotypes,gut microbes,gut metabolite structure and anti-obesity pathways,which were obtained for the first time,provide foundations for developing functional Pu-erh tea.
基金supported by the National Natural Science Foundation of China(Nos.21771060 and 61271126)the International Science&Technology Cooperation Program of China(No.2016YFE0115100)+2 种基金Heilongjiang Provincial Natural Science Foundation of China(No.LH_(2)023B021)Reform and Development Fund Project of Local University supported by the Central Government,Heilongjiang Touyan Innovation Team Program,New Era Excellent Master’s and Doctoral Dissertations of Heilongjiang Province(No.LJYXL2023-020)Basic Scientific Research Project for Heilongjiang Provincial Colleges and Universities(No.2023-KYYWF-1482).
文摘Acetone is a common volatile organic compound that can cause harm to human health when inhaled in small amounts.Therefore,the development of fast response and low detection limit acetone sensors becomes crucial.In this study,a core-shell spherical TiO_(2) sensor with a rich pore structure was designed.This sensor exhibited excellent sensing properties,including higher responsiveness(100 ppm acetone,R_(a)/R_(g)=80),lower detection limit(10 ppb)and short response time(8 s).The problem is that the sensing mechanism between TiO_(2) and acetone is not thoroughly analyzed.To gain further insight,the interaction process of TiO_(2) core-shell spheres and acetone under varying oxygen content environments was investigated by dynamic testing,X-ray photoelectron spectroscopy,in-situ Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry.The research results show that acetone not only adsorbs on the surface of the material and reacts with adsorbed oxygen,but also undergoes catalytic oxidation reaction with TiO_(2) core-shell spheres.Significantly,in high oxygen content environments,acetone undergoes oxidation to form intermediates such as acids and anhydrides that are difficult to desorpt on the surface of the material,thus prolonging the recovery time of the sensor.The discovery of this sensing process will provide some guidance for the design of acetone sensing materials in the future.Meanwhile,this also imparts valuable references and insights for the investigation of the mechanism and application of other sensitive metal oxide materials.
基金financially supported by the National Natural Science Foundation of China(No.52004339)the Key Research and Development Project of Hunan Province,China(No.2022SK2075)+1 种基金China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202216)Central South University Graduate Student Independent Exploration and Innovation Project(2024ZZTS0378).
文摘The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were used to investigate the effects of temperature(700–1100℃),CO_(2)(3%–10%),and H_(2)O(1%–9%)concentrations on CH_(4) conversion efficiency.Results indicate that CH_(4) conversion exceeds 90%at temperatures above 1000℃,with CO_(2) and H_(2)O concentrations at 9%and 5%,respectively.During the reforming process,introducing CO_(2) provides additional oxygen,facilitating the oxidation of CH_(4),while H_(2)O enhances H_(2) production through the steam reforming pathway.Experimental findings reveal a CH_(4) conversion of 85.83%with a H_(2)/CO ratio of 5.44 at 1050℃.In addition,an optimal H_(2)O concentration of 6%yields the highest CH_(4) conversion of 84.24%,while CO_(2) exhibits minimal effects on promoting the reforming process.Increasing the metallization rate of pellets from 43%to 92%significantly enhances CH_(4) reforming.This is mainly due to the fact that metallized iron is vital in promoting CH_(4) dissociation and improving syngas yield by providing active sites for the redox cycle of CO_(2) and H_(2)O.
基金the National Natural Science Foundation of China(No.52341401)the National Key Research and Development Program of China under grant(No.2022YFE0206700)+4 种基金the National Natural Science Foundation of China(No.42302272)the State-funded Postdoctoral Fellowship Program(No.GZB20230862)the Science Foundation of China University of Petroleum,Beijing(No.2462023XKBH006)the Science Foundation of China University of Petroleum,Beijing(No.2462021YJRC012)the Open Project Program of Key Laboratory of Groundwater Resources and Environment(Jilin University),Ministry of Education(No.202306ZDKF05).
文摘With policy support for carbon capture,utilization,and storage(CCUS),an integrated approach that combines energy storage fracturing,CO_(2)-enhanced oil recovery(EOR),and storage emerges as a promising direction for the shale oil industry.The process of energy storage fracturing induces significant changes in the pressure and saturation of the medium.However,conventional simulations often overlook the effects of fracturing and shut-in operations on the seepage field and production performance.Furthermore,fractured shale reservoirs exhibit complex non-Darcy flow characteristics due to intricate pore structures and multi-scale porous media.A comprehensive understanding of flow mechanisms is essential for effective reservoir development and CO_(2) storage.This study establishes a multi-component simulation model that encompasses the life-cycle of fracturing,shut-in,production,and CO_(2) huff-n-puff processes,thereby ensuring the continuity of the seepage field.The model accounts for the effect of nano-confinement on phase behavior by modifying the equation of state.Furthermore,the flux term is adjusted to incorporate Maxwell–Stefan diffusion,pre-/post-Darcy flow,and stress sensitivity.The embedded discrete fracture model(EDFM)is employed to simulate multiphase flow within multi-scale media,and the results from the validation model align satisfactorily with those derived from ECLIPSE.Mechanism analysis indicates that the interaction of multiple mechanisms significantly influences both production and storage performance.Under the multi-mechanism coupling,the cumulative oil production increased by 12.01%,while the utilization and storage factors increased by 62.93%and 8.93%,respectively.The role of molecular diffusion in shale oil reservoirs may be overstated,contributing only a 0.26% enhancement in oil production.Simulation results show that the energy storage fracturing strategy can increase oil production and net present value by 12.47%and 15.07%,respectively.Sensitivity analysis indicates that the CO_(2) injection rate is the main factor affecting the recovery factor,followed by CO_(2) injection time and the number of cycles,with fracturing fluid volume having the least impact.This study develops a multi-process,multi-mechanism simulation framework for multi-scale shale oil reservoirs.This framework provides a robust evaluation system for CCUS-EOR,facilitating informed decision-making in fracturing stimulation,development planning,and parameter optimization.
基金financially supported by the National Key Research and Development Program of China(Grant No.2023YFC3008001)the National Natural Science Foundation of China(Grant No.52371357)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515240035)。
文摘Underwater Gliders(UGs)have emerged as vital instruments in marine research,offering distinct advantages including low operational costs,extended range capabilities,and superior durability.Traditional UGs,however,face limitations due to their substantial size,weight,cost,and deployment complexity.Moreover,the conventional oil pump method for buoyancy adjustment exhibits slow response times,resulting in increased unsteady gliding depth ratios.These constraints limit their application in shallow water environments such as ports,coastal waters,and inland water bodies.This paper presents the TL-200,a small-sized underwater glider that incorporates an integrated buoyancy-driven and attitude adjustment mechanism.Through the implementation of an innovative buoyancy drive unit,the TL-200 achieves enhanced buoyancy regulation response while maintaining a simplified structure compared to conventional gliders.A dynamic model for the TL-200 was developed and validated through comparative analysis of numerical results and experimental data.Utilizing this dynamic model,motion simulations were conducted to examine the influence of metacentric height on motion parameters.Additionally,the study evaluated the gliding efficiency and energy consumption of the TL-200 under varying buoyancy adjustments.The findings demonstrate the effectiveness of this small-sized underwater glider's integrated buoyancy-driven and attitude adjustment mechanism.
基金supported by the Natural Science Foundation of Hubei Provincial Department of Education(D20232101)Shandong Second Medical University 2024 Affiliated Hospital(Teaching Hospital)Scientific Research Development Fund Project(2024FYQ026)+3 种基金the innovative Research Programme of Xiangyang No.1 People’s Hospital(XYY2023ZY01)Faculty Development Grants of Xiangyang No.1 People’s Hospital Affiliated to Hubei University of Medicine(XYY2023D05)Joint supported by Hubei Provincial Natural Science Foundation and Xiangyang of China(2025AFD091)Traditional Chinese Medicine Scientific Research Project of Hubei Provincial Administration of Traditional Chinese Medicine(ZY2025D019).
文摘Background:Diabetic foot,a severe complication of diabetes,is characterized by chronic refractory wounds.Sanhuang Oil,a topical herbal formula,demonstrates significant therapeutic effects including antibacterial,anti-inflammatory,and immunomodulatory activities.However,its active constituents and mechanisms of action against diabetic foot remain to be elucidated.Methods:In this study,the chemical constituents of Sanhuang Oil were identified using UPLC-QE-Orbitrap-MS.Subsequently,the mechanism by which Sanhuang Oil promotes diabetic foot ulcer healing was predicted by integrating network pharmacology and molecular docking.Additionally,diabetic mouse model was established in ICR mice using a combination of a high-fat diet(HFD)and streptozotocin(STZ)chemical induction.A full-thickness skin defect was created on the dorsum of the mice.Wound healing and the healing rate were observed following Sanhuang Oil intervention.The mechanism underlying Sanhuang Oil’s promotion of diabetic ulcer healing was further investigated using transcriptomics and histopathological examination(H&E staining).Results:A total of 97 active ingredients were identified from Sanhuang Oil.Network pharmacology analysis predicted 543 common targets,and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis identified 203 relevant pathways.Molecular docking further confirmed high binding affinity(binding energy≤−5.0 kcal/mol)between specific active components in Sanhuang Oil(e.g.,coptisine,phellodendrine,baicalein)and key targets associated with diabetic foot ulcers(e.g.,EGFR,AKT1,STAT3).In vivo experimental results demonstrated that the wound healing rate was significantly higher in Sanhuang Oil-treated groups compared to the model group(P<0.001).HE staining revealed that the high-dose Sanhuang Oil group exhibited more pronounced epithelial tissue coverage over the wound,reduced inflammatory cell infiltration,and increased collagen deposition and fibroblast proliferation.transcriptomic analysis identified Pdk4,Ttn,Csrp3,Actn2,Myoz2,Tnnc2,Myod1,Myog,Myot,and Myf6 as key regulatory proteins involved in promoting wound healing.Conclusion:Sanhuang Oil promotes wound healing in diabetic ulcer mice,potentially by mitigating inflammation and regulating key targets such as Pdk4 to enhance fibroblast function.These findings provide novel insights into the multi-target,multi-pathway mechanism of Sanhuang Oil for treating diabetic foot ulcers.
基金supported by the National Natural Science Foundation of China(Nos.52364044 and 52204364)Central Guidance on Local Science and Technology Development Fund Projects of Inner Mongolia Autonomous Region(No.2022ZY0090)Basic Scientific Research Business Expenses of Colleges and Universities in Inner Mongolia Autonomous Region(Nos.2023QNJS011 and 0406082226).
文摘The micro-area characterization experiments like scanning Kelvin probe force microscope(SKPFM)and Kernel average misorientation have the defects of complex sample preparation and occasional errors in test results,which makes it impossible to accurately and quickly analyze the pitting behavior induced by inclusions in some cases,prompting attempts to turn to simulation calculation research.The method of calculating band structure and work function can be used to replace current-sensing atomic force microscopy and SKPFM to detect the potential and conductivity of the sample.The band structure results show that Al_(2)O_(3) inclusion is an insulator and non-conductive,and it will not form galvanic corrosion with the matrix.Al_(2)O_(3) inclusion does not dissolve because its work function is higher than that of the matrix.Moreover,the stress concentration of the matrix around the inclusion can be characterized by first-principles calculation coupled with finite element simulation.The results show that the stress concentration degree of the matrix around Al_(2)O_(3) inclusion is serious,and the galvanic corrosion is formed between the high and the low stress concentration areas,which can be used to explain the reason of the pitting induced by Al_(2)O_(3) inclusions.
基金Sponsored by Natural Science Foundation of Hebei Province(Grant No.E2019209153)Tangshan Science and Technology Program(Grant No.22130219G).
文摘The contact characteristics between cycloidal gear teeth and pinwheel teeth significantly impact the operational performance of cycloidal pinwheel mechanisms.Current research methods tend to rely primarily on theoretical calculations,with limited use of experimental methods for detecting dynamic contact properties.We propose a novel method for testing the dynamic contact characteristics of cycloidal pinwheel mechanisms.By combining Hertzian contact theory and contact strength theory,we establish a force and meshing stiffness model for the cycloidal and pinwheel gears,and determine the maximum contact stress and variations in pinwheel gear force and meshing stiffness.Based on the principle of photoelasticity,we built a testing platform for the cycloidal pinwheel mechanism to assess its contact characteristics.This platform provides the stress distribution of the cycloidal pinwheel mechanism and allows us to deduce key parameters such as the number of meshing teeth and the meshing interval.This study provides an experimental method for investigating the contact characteristics of cycloidal pinwheel mechanisms.
基金Research on the Quality Verification of Applied University Talent Cultivation Based on the“Five Degrees,”a major project of university-level talent training quality and teaching reform in 2023(TFCJGZD202303)。
文摘Teaching quality is the core guarantee for universities to achieve their talent cultivation goals,and teaching supervision,as an important means of monitoring teaching quality,runs through the entire process of teaching management.Based on the teaching quality report of School A at University Z for the autumn semester of 2024,this paper systematically analyzes the current situation,problems,and causes of the teaching supervision mechanism through multi-dimensional data analysis of expert classroom observation,peer evaluation,and classroom feedback.On this basis,combined with the application prospects of artificial intelligence technology,it proposes paths to optimize the teaching supervision mechanism,including improving the classroom observation feedback mechanism,increasing supervision coverage,and strengthening the linkage between feedback and teaching reform,providing practical experience and theoretical support for improving teaching quality in universities.
