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
To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid d...To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid dynamics(CFD)analysis.First,a CFD analysis of a two-bladed VAWT equipped with a NACA 0012 airfoil is conducted.The thrust and power coefficients are validated through experiments.Second,the blade force and velocity data at monitoring points are collected.The AOA at different azimuth angles is determined by removing the blade self-induction at the monitoring point.Then,the lift and drag coefficients as a function of AOA are extracted.Results show that this method is independent of the monitoring points selection located at certain distance to the blades and the extracted dynamic stall hysteresis is more precise than the one with the“usual”method without considering the self-induction from bound vortices.展开更多
To examine the effect of bedding angle upon burst proneness in terms of energy,phyllites with seven various bedding angles are selected for conventional uniaxial compression and single-cyclic loading eunloading uniaxi...To examine the effect of bedding angle upon burst proneness in terms of energy,phyllites with seven various bedding angles are selected for conventional uniaxial compression and single-cyclic loading eunloading uniaxial compression tests.The ejection and failure during compression process of phyllites are monitored in real-time by high-speed camera system.The results demonstrate that the phyllites with different bedding angles all consistently follow the linear energy storage and dissipation(LESD)law during compression.The ultimate energy storage of phyllites with varying bedding angles can be calculated precisely via using the LESD law.Based on this,four kinds of energy-based rockburst indices are applied to quantitatively assess the burst proneness for phyllites.Combined with the recorded images of high-speed camera system,ejection distance,and mass of rock fragments and powder,the burst proneness for phyllites with various bedding angles is qualitatively evaluated adopting the far-field ejection mass ratio.Next,burst proneness of anisotropic phyllites is assessed quantitatively and qualitatively.It is found that phyllites with bedding angles of 0°,15°,and 90°have a high burst proneness,and that with bedding angle of 30°has a medium burst proneness,whereas the ones with bedding angles of 45°,60°,and 75°have a low burst proneness.Finally,the published experimental data of shale and sandstone specimens with different bedding angles are extracted,and it is preliminarily verified that the bedding angle does not change the LESD law of rocks.展开更多
In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-...In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture.The results demonstrated that the boundary of the gas transport zone was located in the region of fracture separation.The boundary of the gas storage area was located in the abrupt penetration zone.Also,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture entropy.The mathematical representation model of the dip effect in gas transport and storage areas was established.The criteria upon which the regional location of the gas transport area and gas storage area can be based were put forward.The cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as well.The research results could provide guidance for realising directional and accurate gas extraction.展开更多
Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,wh...Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter.The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation.The equation of motion for stall flutter is solved by the Newmark-β method.Then,the stall flutter responses for five blowing speeds,i.e.,0,4,12,20,and 28 m/s under the airspeed range of 3–9 m/s,are studied in detail.The stall flutter suppression mechanism can be summarized as follows:a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone,which delays the flow separation on the suction surface.In this way,the formation of the leading-edge separation vortex is suppressed.Thus,the dynamic stall vortex is weakened and accelerates shedding.In addition,the driving moment is reduced,which leads to a decrement in the stall flutter amplitude.When the blowing speed is 28 m/s(stall flutter amplitude=0.1357 rad),compared with uncontrolled case(stall flutter amplitude=0.6002 rad),the amplitude can decrease by 77.39%,which demonstrates the effectiveness of the proposed steady blowing based active control strategy.展开更多
Branch angles are an important plant morphological trait affecting light interception within forest canopies.However,studies on branch angles have been limited due to the time-consuming nature of manual measurements u...Branch angles are an important plant morphological trait affecting light interception within forest canopies.However,studies on branch angles have been limited due to the time-consuming nature of manual measurements using a protractor.Terrestrial laser scanning(TLS),however,provides new opportunities to measure branch angles more efficiently.Despite this potential,studies validating branch angle measurements from TLS have been limited.Here,our aim is to evaluate both manual and automatic branch angle measurements of European beech from TLS data using traditional field-measurements with a protractor as a reference.We evaluated the accuracy of branch angle measurements based on four automated algorithms(aRchiQSM,TreeQSM,Laplacian,SemanticLaplacian)from TLS data.Additionally,we assessed different ways of manual branch angle measurements in the field.Our study was based on a dataset comprising 124 branch angles measured from six European beech in a European deciduous forest.Our results show that manual branch angle measurements from TLS data are in high agreement with the reference(root-mean-squared error,RMSE:[3.57°-4.18°],concordance correlation coefficient,CCC:[0.950.97])across different branch length positions.Automated algorithms also are in high agreement with the reference although RMSE is approximately twice as large compared to manual branch angle measurements from TLS(RMSE:[9.29°-10.55°],CCC:[0.830.86])with manual leaf points removal.When applying the automatic wood-leaf separation algorithm,the performance of the four methods declined significantly,with only approximately 20 branch angles successfully identified.Moreover,it is important to note that there is no influence of the measurement position(branch surface versus center)for branch angle measurements.However,for curved branches,the selection of branch measurement length significantly impacts the branch angle measurement.This study provides a comprehensive understanding of branch angle measurements in forests.We show that automated measurement methods based on TLS data of branch angles are a valuable tool to quantify branch angles at larger scales.展开更多
Endodermal cells and starch-accumulating amyloplasts are well-known gravity sensors initiating shoot gravitropism in Arabidopsis thaliana.The transcription factors SHR and SGR1 regulate endodermal cell formation,while...Endodermal cells and starch-accumulating amyloplasts are well-known gravity sensors initiating shoot gravitropism in Arabidopsis thaliana.The transcription factors SHR and SGR1 regulate endodermal cell formation,while PGM has been demonstrated to regulate starch biosynthesis within chloroplasts,which eventually leads to starch accumulation in amyloplasts.However,the molecular mechanisms of gravity sensing in monocot shoots remain largely unexplored.In this study,we investigated the roles of these genes in rice(Oryza sativa),a model monocot,using CRISPR-Cas9 to generate single,double,and higher-order mutants.The rice genome harbors two orthologs each of SHR and SGR and a single ortholog of PGM.Our results revealed that single mutants of OsPGM,but not OsSHR or OsSGR,showed compromised shoot gravitropism.However,double mutants shr1shr2 and sgr1sgr2 displayed wider tiller angles and reduced gravity sensing,suggesting functional redundancy within each gene pair.Higher-order mutants exhibited progressively severe phenotypes,with quintuple mutants almost unresponsive to gravity stimulation.These findings suggest that these genes act additively through distinct but converging pathways in shoot gravitropism regulation.This study provides novel insights into the molecular mechanisms underlying gravity sensing in monocots and offers valuable knowledge for precision breeding to optimize rice architecture.展开更多
AIM:To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.METHODS:A retrospective review was conducted on the medical records of patients with basic-type strabismus.De...AIM:To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.METHODS:A retrospective review was conducted on the medical records of patients with basic-type strabismus.Demographic data,refractive error,best-corrected distance visual acuity(BCVA),and the horizontal and vertical angle of deviation between basic esotropia and exotropia patients were compared.RESULTS:Among the 7129 patients(mean age 22.98±14.81y)evaluated,44.7%(3185 cases,54.9%male)exhibited basic-type esotropia,while 55.3%(3944 cases,53.9%male)presented with basic-type exotropia.Basic esotropia cases exhibited more hyperopic spherical equivalent measurements in both eyes(right:0.53±3.07 vs left:0.56±2.98 D)than those with basic exotropia(right eye:-0.33±2.84 vs left eye:-0.24±2.68 D,P<0.001 for both eyes).Patients with basic esotropia had significantly greater horizontal deviation angles(near:36.08±18.87 PD and far:35.56±18.75 PD)compared to those with basic exotropia(near:33.75±16.11 PD and far:33.26±15.90 PD,P<0.001).Conversely,patients with basic exotropia had slightly higher vertical deviation angles(near:1.67±5.80 PD and far:1.72±5.89 PD)compared to those with basic esotropia(near:1.12±4.57 PD and far:1.12±4.58 PD,P<0.001).Patients with basic esotropia underwent surgical intervention at younger ages compared to basic exotropia individuals(19.68±15.99 vs 25.66±13.20,P<0.001).CONCLUSION:Basic esotropia patients present more hyperopic refractive errors,better visual acuity,larger horizontal yet smaller vertical ocular misalignments,and tend to undergo strabismus surgery at younger ages relative to basic exotropia cases.展开更多
Despite numerous research investigations to understand the influences of various structural parameters,to the authors'knowledge,no research has been the effect of different angles of incidence on stab response and...Despite numerous research investigations to understand the influences of various structural parameters,to the authors'knowledge,no research has been the effect of different angles of incidence on stab response and performance of different types of protective textiles.Three distinct structures of 3D woven textiles and 2D plain weave fabric made with similar high-performance fiber and areal density were designed and manufactured to be tested.Two samples,one composed of a single and the other of 4-panel layers,from each fabric type structure,were prepared,and tested against stabbing at[0○],[22.5○],and[45○]angle of incidence.A new stabbing experimental setup that entertained testing of the specimens at various angles of incidence was engineered and utilized.The stabbing bench is also equipped with magnetic sensors and a UK Home Office Scientific Development Branch(HOSDB)/P1/B sharpness engineered knives to measure the impact velocity and exerted impact energy respectively.A silicon compound was utilized to imprint the Back Face Signature(BFS)on the backing material after every specimen test.Each silicon print was then scanned,digitized,and precisely measured to evaluate the stab response and performance of the specimen based on different performance variables,including Depth of Trauma(DOT),Depth of Penetration(DOP),and Length of Penetration(LOP).Besides,the post-impact surface failure modes of the fabrics were also measured using Image software and analyzed at the microscale level.The results show stab angle of incidence greatly influences the stab response and performance of protective textiles.The outcome of the study could provide not only valuable insights into understanding the stab response and capabilities of protective textiles under different angle of incidence,but also provide valuable information for protective textile manufacturer,armor developer and stab testing and standardizing organizations to consider the angle of incidence while developing,testing,optimizing,and using protective textiles in various applications.展开更多
The spatial relationship between structural planes and principal stresses significantly affects the mechanical properties of deep hard rock.This paper examines the effect of the loading angle under true triaxial compr...The spatial relationship between structural planes and principal stresses significantly affects the mechanical properties of deep hard rock.This paper examines the effect of the loading angle under true triaxial compression.While previous studies focused on the angleβbetween the maximum principal stress and the structural plane,the role of angleω,between the intermediate principal stress and the structural plane,is often overlooked.Utilizing artificially prefabricated granite specimens with a single non-penetrating structural plane,we set the loading angleβto range from 0°to 90°across seven groups,and assignedωvalues of 0°and 90°in two separate groups.The results show that the peak strength is negatively correlated withβup to 45°,beyond which it tends to stabilize.The angleωexerts a strengthening effect on the peak strength.Deformation mainly occurs post-peak,with the strain values ε_(1) and ε_(3) reaching levels 2−3 times higher than those in intact rock.The structural plane significantly influences failure mode whenω=0°,while failure localizes near the σ_(3) surface of the specimens whenω=90°.The findings enhance data on structural plane rocks under triaxial compression and inform theoretical research,excavation,and support design of rock structures.展开更多
Ceramic cores fabricated by stereolithography exhibit great potential in casting turbine blades.Previous research on ceramic core molding was primarily conducted using vertical printing techniques,which not only resul...Ceramic cores fabricated by stereolithography exhibit great potential in casting turbine blades.Previous research on ceramic core molding was primarily conducted using vertical printing techniques,which not only resulted in lengthy molding durations but also compromised the mechanical strength.In this work,silica(SiO--_2)ceramic cores,with fine complex geometric shapes,were fabricated using 65vol.%ceramic slurry by digital light processing(DLP)with different printing angles.Printing angles significantly impact the surface accuracy,shrinkage,printing efficiency of green bodies,as well as the microstructure and mechanical properties of sintered ceramic core samples.As the printing angle in the green body increases,the bonding area decreases,surface roughness on the XY plane worsens,shrinkage in the Z direction becomes more pronounced,and the printing efficiency declines.Similarly,an increase in the printing angle in the sintered body leads to a reduction in bending strength.At a printing angle of 30°,the printing time is reduced to half of that at 90°,which improves the molding efficiency.Meanwhile,the obtained bulk density of 1.71 g·cm~(-3),open porosity of 24%,and fiexural strength of 10.6±1 MPa can meet the requirements of sintered ceramic cores.Therefore,designing and optimizing the printing angles can achieve the balance between shrinkage,printing efficiency,and fiexural strength.展开更多
The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-domin...The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.展开更多
The marine propeller typically functions within thefilowfiield generated by a water vehicle.Investigations into the geometric parameters of the propeller are commonly conducted under open‑water conditions as simultane...The marine propeller typically functions within thefilowfiield generated by a water vehicle.Investigations into the geometric parameters of the propeller are commonly conducted under open‑water conditions as simultaneously simulating both vehicle and propeller holds several computational challenges.While during operation,this propellant device must face several forces like gravity,hydrodynamic load,and centrifugal force,which cause different problems like cavitation and structural failure,etc.Since these issues affect performance,it necessitates comprehensive analysis.In this study,hydrodynamic analysis is performed by using commercial software STAR CCM+.In hydrodynamic analysis,the effect of the rake angles–5°,5°,10°and 15°on hydrodynamic coeffiicients and effiiciency of the DTMB 4119 in the open water is analyzed using Computational Fluid Dynamics(CFD)and the control volume approach.The Shear Stress Transport(SST)k‑ωturbulence model is used in Computational Fluid Dynamics(CFD)simulation.Hydrodynamic analysis reveals that the rake angles 5°and 10°cause the open water effiiciency of David Taylor Model Basin(DTMB)4119 to improve by 0.4 to 1.32%with exception of the rake angles–5°and 15°,which possess different effects on effiiciency.The angle–5°causes a decrease in propeller effiiciency under heavy loading situations(low advance coeffiicient)apart from a minorfiluctuation at light loading conditions(high advance coeffiicient),while the angle 15°produces a drop in effiiciency by higher advance ratios but little variation at lower advance ratios.展开更多
AIM:To investigate the role of adipokines in primary open angle glaucoma(POAG)by comparing the levels of these molecules in the aqueous humor among POAG patients and cataract patients with or without metabolic disorde...AIM:To investigate the role of adipokines in primary open angle glaucoma(POAG)by comparing the levels of these molecules in the aqueous humor among POAG patients and cataract patients with or without metabolic disorders.METHODS:In this cross-sectional study,aqueous humor samples of 22 eyes of POAG patients(POAG group),24 eyes of cataract patients without metabolic disorders(cataract group),and 24 eyes of cataract patients with metabolic disorders(cataract+metabolic disorders group)were assessed for 15 adipokines by Luminex bead-based multiplex array.The correlation between aqueous humor adipokines and clinical indicators of POAG was analyzed and compared across the groups.RESULTS:The analysis revealed that the levels of adiponectin,leptin,adipsin,retinol-binding protein 4(RBP4),angiopoietin-2,angiopoietin-like protein 4(ANGPTL4),chemokine(C-C motif)ligand 2(CCL2),interleukin-8(IL-8),and interleukin-18(IL-18)in the aqueous humor of the POAG group were significantly higher than those in the cataract group.Additionally,the level of angiopoietin-2 in the POAG group was higher than in the cataract+metabolic disorders group.However,no significant correlation was found between the levels of adipokines in the POAG group and intraocular pressure(IOP),severity of POAG,or the use of glaucoma medications.CONCLUSION:This study demonstrates significant differences in aqueous humor adipokine levels between POAG and cataract patients.The findings suggest that the levels of aqueous humor adipokines may reflect the inflammatory states in POAG and systemic metabolic abnormalities.展开更多
Rapid and reliable onboard optimization of bank angle profiles is crucial for mitigating uncertainties during Mars atmospheric entry.This paper presents a neural-network-accelerated methodology for optimizing parametr...Rapid and reliable onboard optimization of bank angle profiles is crucial for mitigating uncertainties during Mars atmospheric entry.This paper presents a neural-network-accelerated methodology for optimizing parametric bank angle profiles in Mars atmospheric entry missions.The methodology includes a universal approach to handling path constraints and a reliable solution method based on the Particle Swarm Optimization(PSO)algorithm.For illustrative purposes,a mission with the objective of maximizing terminal altitude is considered.The original entry optimization problem is converted into optimizing three coefficients for the bank angle profiles with terminal constraints by formulating a parametric Mars entry bank angle profile and constraint handling methods.The parameter optimization problem is addressed using the PSO algorithm,with reliability enhanced by increasing the PSO swarm size.To improve computational efficiency,an enhanced Deep Operator Network(Deep ONet)is used as a dynamics solver to predict terminal states under various bank angle profiles rapidly.Numerical simulations demonstrate that the proposed methodology ensures reliable convergence with a sufficiently large PSO swarm while maintaining high computational efficiency facilitated by the neural-network-based dynamics solver.Compared to the existing methodologies,this methodology offers a streamlined process,the reduced sensitivity to initial guesses,and the improved computational efficiency.展开更多
With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This...With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This study investigates the influence of prefabricated crack dip angles on the mechanical properties of anchored rock masses in deep soft rock roadways.By constructing similarity models of NPR(Negative Poisson’s Ratio)and PR(Positive Poisson’s Ratio)anchored solids,biaxial compression experiments under varying crack dip angles were conducted.Strain gauges,3D Digital Image Correlation(3D DIC),and acoustic emission monitoring were employed to systematically analyze the strength characteristics,deformation-damage evolution,and energy dissipation mechanisms of the two types of anchor systems.The results show that:(1)The stress-strain curves of anchored solids with prefabricated cracks exhibit a distinct bimodal characteristic.Compared to PR anchors,NPR anchors show 20%and 23%improvements in peak strength and elastic modulus,respectively,with residual strength enhanced by up to 34%.(2)Owing to high pre-tightening force and large deformation capacity,NPR anchors maintain superior integrity under increasing crack dip angles,demonstrating more uniform free-surface displacement and localized shear-tensile composite crack patterns.(3)Acoustic emission analysis reveals that NPR anchors exhibit higher cumulative energy absorption(300%improvement over PR anchors)and lack low-rate energy development phases,indicating enhanced ductility and impact resistance at high crack dip angles.(4)Crack dip angle critically governs failure mechanisms by modulating the connectivity between shear cracks and prefabricated fissures:bimodal effects dominate at low angles,while vertical tensile crack propagation replaces bimodal behavior at high angles.The study proposes prioritizing NPR anchor cables in deep engineering applications and optimizing support parameters based on crack dip angles to mitigate stress concentration and ensure the long-term stability of surrounding rock.展开更多
This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation freq...This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation frequencies.Results reveal that the eigenfrequencies vary spatially due to distinct oscillation modes occurring at different droplet locations.Notably,the fundamental eigenfrequency decreases with reducing droplet volume,while droplet viscosity exerts minimal influence on this frequency.Prior to the onset of motion,the dynamic contact angle consistently remains between the advancing and receding angles.The inertial forces generated by droplet oscillation are found to be significantly greater than the adhesion forces,indicating that classical static models are inadequate for capturing inertial contributions to droplet motion.These findings offer new insights into the role of oscillatory behavior in influencing the dynamics of droplet motion,and contribute to a more detailed understanding of wind-driven droplet transport phenomena.展开更多
This study introduces the lattice spring model(LSM)to investigate the incline angle of a non-uniform three-segment towed array under steady-state conditions.A numerical model was established,and parametric analysis wa...This study introduces the lattice spring model(LSM)to investigate the incline angle of a non-uniform three-segment towed array under steady-state conditions.A numerical model was established,and parametric analysis was conducted to examine the effects of towing speed and cable density on the incline angle.The numerical simulations demonstrate that for a conventional three-segment towed array with heavy vibration-isolation cable and density exceeding that of seawater,the towing speed must exceed 4 kn to maintain the acoustic cable's average incline angle below 10°.To validate the proposed LSM,a 100-meter-long towed array with variable densities was fabricated and tested through lake trials.The experimental results align closely with simulations,confirming LSM as a reliable model for predicting towed array position and posture.The study concludes by analyzing the parallel computing capabilities of LSM and its application in Fluid-Structure Interaction(FSI)problems.The model's precision and parallel computing capabilities make LSM an efficient,reliable tool for analyzing the steady-state behavior of towed systems.展开更多
This study explores the influence of rotor blade angle on stall inception in an axial fan by means of numerical simulations grounded in the Reynolds-Averaged Navier-Stokes(RANS)equations and the Realizable k-εturbule...This study explores the influence of rotor blade angle on stall inception in an axial fan by means of numerical simulations grounded in the Reynolds-Averaged Navier-Stokes(RANS)equations and the Realizable k-εturbulence model.By analyzing the temporal behavior of the outlet static pressure,along with the propagation velocity of stall inception,the research identifies distinct patterns in the development of stall.The results reveal that stall inception originates in the second rotor impeller.At a blade angle of 27°,the stall inception follows a modal wave pattern,while in all other cases,it assumes the form of spike-type stall.The flow field associated with spike stall inception demonstrates a relatively uniform gradient in the radial direction,whereas the modal wave stall case displays a distinctive“L”-shaped propagation feature.At blade angles of multiple stall inceptions are observed.-9°and-18°,These phenomena initiate at the blade’s leading edge,propagate along both axial and radial directions,and transition dynamically between single and multiple inception states.展开更多
AIM:To explore whether plasma proteins serve as potential therapeutic targets for primary open angle glaucoma(POAG)based on a Mendelian randomization(MR)study.METHODS:Large-scale protein quantitative trait loci(pQTLs)...AIM:To explore whether plasma proteins serve as potential therapeutic targets for primary open angle glaucoma(POAG)based on a Mendelian randomization(MR)study.METHODS:Large-scale protein quantitative trait loci(pQTLs)data from the Icelandic deCODE database and two large POAG Genome-Wide Association Study(GWAS)summary datasets were used in this study.Causal associations between plasma proteins and POAG were identified using summary-data-based MR(SMR)analysis and the heterogeneity in dependent instruments(HEIDI)test.Colocalization analysis was then conducted to assess the genetic associations between these two factors.Phenotype-wide MR analysis was performed to validate protein targets as potential drug targets and to evaluate potential side effects.Finally,protein-protein interactions(PPI)were studied,and the Drug-Gene Interaction Database(DGIDb)was used to identify associations between drugs and the identified proteins.RESULTS:Four proteins(SVEP1,TMEM190,ROBO1,and ENPP5)were identified as potential drug targets in this study.Phenome-wide MR analysis showed that SVEP1,ROBO1,and ENPP5 were not associated with adverse effects,while TMEM190 was linked to nerve root and plexus disorders,as well as subarachnoid hemorrhage.Ticagrelor was suggested as a potential new drug for the treatment of glaucoma by regulating SVEP1.CONCLUSION:Four plasma proteins—SVEP1,TMEM190,ROBO1,and ENPP5—are identified as potential therapeutic targets for POAG through an MR approach.Phenome-wide MR analysis reveals that SVEP1,ROBO1,and ENPP5 are not associated with adverse effects,while TMEM190 is linked to nerve root and plexus disorders,as well as subarachnoid hemorrhage.Ticagrelor is proposed as a potential therapeutic drug for glaucoma by regulating SVEP1.These findings highlight the potential of plasma proteins as drug targets for POAG and provide valuable insights for further research.展开更多
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.
文摘To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid dynamics(CFD)analysis.First,a CFD analysis of a two-bladed VAWT equipped with a NACA 0012 airfoil is conducted.The thrust and power coefficients are validated through experiments.Second,the blade force and velocity data at monitoring points are collected.The AOA at different azimuth angles is determined by removing the blade self-induction at the monitoring point.Then,the lift and drag coefficients as a function of AOA are extracted.Results show that this method is independent of the monitoring points selection located at certain distance to the blades and the extracted dynamic stall hysteresis is more precise than the one with the“usual”method without considering the self-induction from bound vortices.
基金supported by the National Natural Science Foundation of China(Grant No.42077244).
文摘To examine the effect of bedding angle upon burst proneness in terms of energy,phyllites with seven various bedding angles are selected for conventional uniaxial compression and single-cyclic loading eunloading uniaxial compression tests.The ejection and failure during compression process of phyllites are monitored in real-time by high-speed camera system.The results demonstrate that the phyllites with different bedding angles all consistently follow the linear energy storage and dissipation(LESD)law during compression.The ultimate energy storage of phyllites with varying bedding angles can be calculated precisely via using the LESD law.Based on this,four kinds of energy-based rockburst indices are applied to quantitatively assess the burst proneness for phyllites.Combined with the recorded images of high-speed camera system,ejection distance,and mass of rock fragments and powder,the burst proneness for phyllites with various bedding angles is qualitatively evaluated adopting the far-field ejection mass ratio.Next,burst proneness of anisotropic phyllites is assessed quantitatively and qualitatively.It is found that phyllites with bedding angles of 0°,15°,and 90°have a high burst proneness,and that with bedding angle of 30°has a medium burst proneness,whereas the ones with bedding angles of 45°,60°,and 75°have a low burst proneness.Finally,the published experimental data of shale and sandstone specimens with different bedding angles are extracted,and it is preliminarily verified that the bedding angle does not change the LESD law of rocks.
基金supported by the National Natural Science Foundation of China(No.5217-4205)Shaanxi Provincial Outstanding Youth Science Fund Project(No.2023-JC-JQ-40)+4 种基金National Key Research and Development Project(No.2023YFC3009004)Key Project of Shaanxi Provincial Department of Education(No.22JY040)Xinjiang Uygur Autonomous Region Key Research and Development Task Special Project(No.2022B01034-3)Key Laboratory of Green Coal Mining in Xinjiang,Ministry of Education(No.KLXGY-KA2404)Shaanxi Provincial Key Research and Development Task General Project(No.2024GX–YBXM-490)。
文摘In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture.The results demonstrated that the boundary of the gas transport zone was located in the region of fracture separation.The boundary of the gas storage area was located in the abrupt penetration zone.Also,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture entropy.The mathematical representation model of the dip effect in gas transport and storage areas was established.The criteria upon which the regional location of the gas transport area and gas storage area can be based were put forward.The cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as well.The research results could provide guidance for realising directional and accurate gas extraction.
基金co-supported by the National Natural Science Foundation of China(Nos.52472394,52425211,52201327,52272360)。
文摘Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter.The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation.The equation of motion for stall flutter is solved by the Newmark-β method.Then,the stall flutter responses for five blowing speeds,i.e.,0,4,12,20,and 28 m/s under the airspeed range of 3–9 m/s,are studied in detail.The stall flutter suppression mechanism can be summarized as follows:a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone,which delays the flow separation on the suction surface.In this way,the formation of the leading-edge separation vortex is suppressed.Thus,the dynamic stall vortex is weakened and accelerates shedding.In addition,the driving moment is reduced,which leads to a decrement in the stall flutter amplitude.When the blowing speed is 28 m/s(stall flutter amplitude=0.1357 rad),compared with uncontrolled case(stall flutter amplitude=0.6002 rad),the amplitude can decrease by 77.39%,which demonstrates the effectiveness of the proposed steady blowing based active control strategy.
基金supported by the Chinese Scholarship Council under Grant 202106910006.
文摘Branch angles are an important plant morphological trait affecting light interception within forest canopies.However,studies on branch angles have been limited due to the time-consuming nature of manual measurements using a protractor.Terrestrial laser scanning(TLS),however,provides new opportunities to measure branch angles more efficiently.Despite this potential,studies validating branch angle measurements from TLS have been limited.Here,our aim is to evaluate both manual and automatic branch angle measurements of European beech from TLS data using traditional field-measurements with a protractor as a reference.We evaluated the accuracy of branch angle measurements based on four automated algorithms(aRchiQSM,TreeQSM,Laplacian,SemanticLaplacian)from TLS data.Additionally,we assessed different ways of manual branch angle measurements in the field.Our study was based on a dataset comprising 124 branch angles measured from six European beech in a European deciduous forest.Our results show that manual branch angle measurements from TLS data are in high agreement with the reference(root-mean-squared error,RMSE:[3.57°-4.18°],concordance correlation coefficient,CCC:[0.950.97])across different branch length positions.Automated algorithms also are in high agreement with the reference although RMSE is approximately twice as large compared to manual branch angle measurements from TLS(RMSE:[9.29°-10.55°],CCC:[0.830.86])with manual leaf points removal.When applying the automatic wood-leaf separation algorithm,the performance of the four methods declined significantly,with only approximately 20 branch angles successfully identified.Moreover,it is important to note that there is no influence of the measurement position(branch surface versus center)for branch angle measurements.However,for curved branches,the selection of branch measurement length significantly impacts the branch angle measurement.This study provides a comprehensive understanding of branch angle measurements in forests.We show that automated measurement methods based on TLS data of branch angles are a valuable tool to quantify branch angles at larger scales.
基金supported by grants from the Biological Breeding-National Science and Technology Major Project(2024ZD04077)the National Natural Science Foundation of China(31801323)+1 种基金the Innovation Program of the Chinese Academy of Agricultural Sciencesthe Science and Technology Innovation Project of the Shandong Academy of Agricultural Sciences(CXGC2023F14)。
文摘Endodermal cells and starch-accumulating amyloplasts are well-known gravity sensors initiating shoot gravitropism in Arabidopsis thaliana.The transcription factors SHR and SGR1 regulate endodermal cell formation,while PGM has been demonstrated to regulate starch biosynthesis within chloroplasts,which eventually leads to starch accumulation in amyloplasts.However,the molecular mechanisms of gravity sensing in monocot shoots remain largely unexplored.In this study,we investigated the roles of these genes in rice(Oryza sativa),a model monocot,using CRISPR-Cas9 to generate single,double,and higher-order mutants.The rice genome harbors two orthologs each of SHR and SGR and a single ortholog of PGM.Our results revealed that single mutants of OsPGM,but not OsSHR or OsSGR,showed compromised shoot gravitropism.However,double mutants shr1shr2 and sgr1sgr2 displayed wider tiller angles and reduced gravity sensing,suggesting functional redundancy within each gene pair.Higher-order mutants exhibited progressively severe phenotypes,with quintuple mutants almost unresponsive to gravity stimulation.These findings suggest that these genes act additively through distinct but converging pathways in shoot gravitropism regulation.This study provides novel insights into the molecular mechanisms underlying gravity sensing in monocots and offers valuable knowledge for precision breeding to optimize rice architecture.
文摘AIM:To compare refractive error and angle of deviation in patients with basic esotropia and basic exotropia.METHODS:A retrospective review was conducted on the medical records of patients with basic-type strabismus.Demographic data,refractive error,best-corrected distance visual acuity(BCVA),and the horizontal and vertical angle of deviation between basic esotropia and exotropia patients were compared.RESULTS:Among the 7129 patients(mean age 22.98±14.81y)evaluated,44.7%(3185 cases,54.9%male)exhibited basic-type esotropia,while 55.3%(3944 cases,53.9%male)presented with basic-type exotropia.Basic esotropia cases exhibited more hyperopic spherical equivalent measurements in both eyes(right:0.53±3.07 vs left:0.56±2.98 D)than those with basic exotropia(right eye:-0.33±2.84 vs left eye:-0.24±2.68 D,P<0.001 for both eyes).Patients with basic esotropia had significantly greater horizontal deviation angles(near:36.08±18.87 PD and far:35.56±18.75 PD)compared to those with basic exotropia(near:33.75±16.11 PD and far:33.26±15.90 PD,P<0.001).Conversely,patients with basic exotropia had slightly higher vertical deviation angles(near:1.67±5.80 PD and far:1.72±5.89 PD)compared to those with basic esotropia(near:1.12±4.57 PD and far:1.12±4.58 PD,P<0.001).Patients with basic esotropia underwent surgical intervention at younger ages compared to basic exotropia individuals(19.68±15.99 vs 25.66±13.20,P<0.001).CONCLUSION:Basic esotropia patients present more hyperopic refractive errors,better visual acuity,larger horizontal yet smaller vertical ocular misalignments,and tend to undergo strabismus surgery at younger ages relative to basic exotropia cases.
文摘Despite numerous research investigations to understand the influences of various structural parameters,to the authors'knowledge,no research has been the effect of different angles of incidence on stab response and performance of different types of protective textiles.Three distinct structures of 3D woven textiles and 2D plain weave fabric made with similar high-performance fiber and areal density were designed and manufactured to be tested.Two samples,one composed of a single and the other of 4-panel layers,from each fabric type structure,were prepared,and tested against stabbing at[0○],[22.5○],and[45○]angle of incidence.A new stabbing experimental setup that entertained testing of the specimens at various angles of incidence was engineered and utilized.The stabbing bench is also equipped with magnetic sensors and a UK Home Office Scientific Development Branch(HOSDB)/P1/B sharpness engineered knives to measure the impact velocity and exerted impact energy respectively.A silicon compound was utilized to imprint the Back Face Signature(BFS)on the backing material after every specimen test.Each silicon print was then scanned,digitized,and precisely measured to evaluate the stab response and performance of the specimen based on different performance variables,including Depth of Trauma(DOT),Depth of Penetration(DOP),and Length of Penetration(LOP).Besides,the post-impact surface failure modes of the fabrics were also measured using Image software and analyzed at the microscale level.The results show stab angle of incidence greatly influences the stab response and performance of protective textiles.The outcome of the study could provide not only valuable insights into understanding the stab response and capabilities of protective textiles under different angle of incidence,but also provide valuable information for protective textile manufacturer,armor developer and stab testing and standardizing organizations to consider the angle of incidence while developing,testing,optimizing,and using protective textiles in various applications.
基金Projects(51979268,52279117,52309146)supported by the National Natural Science Foundation of ChinaProject(SKLGME-JBGS2401)supported by the Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,China。
文摘The spatial relationship between structural planes and principal stresses significantly affects the mechanical properties of deep hard rock.This paper examines the effect of the loading angle under true triaxial compression.While previous studies focused on the angleβbetween the maximum principal stress and the structural plane,the role of angleω,between the intermediate principal stress and the structural plane,is often overlooked.Utilizing artificially prefabricated granite specimens with a single non-penetrating structural plane,we set the loading angleβto range from 0°to 90°across seven groups,and assignedωvalues of 0°and 90°in two separate groups.The results show that the peak strength is negatively correlated withβup to 45°,beyond which it tends to stabilize.The angleωexerts a strengthening effect on the peak strength.Deformation mainly occurs post-peak,with the strain values ε_(1) and ε_(3) reaching levels 2−3 times higher than those in intact rock.The structural plane significantly influences failure mode whenω=0°,while failure localizes near the σ_(3) surface of the specimens whenω=90°.The findings enhance data on structural plane rocks under triaxial compression and inform theoretical research,excavation,and support design of rock structures.
基金the Youth Innovation Promotion Association of Chinese Academy of Science(No.2021160)the National Natural Science Foundation of China(No.51802319)the Technology and Engineering Center for Space(No.CSU-QZKT-2019-04)。
文摘Ceramic cores fabricated by stereolithography exhibit great potential in casting turbine blades.Previous research on ceramic core molding was primarily conducted using vertical printing techniques,which not only resulted in lengthy molding durations but also compromised the mechanical strength.In this work,silica(SiO--_2)ceramic cores,with fine complex geometric shapes,were fabricated using 65vol.%ceramic slurry by digital light processing(DLP)with different printing angles.Printing angles significantly impact the surface accuracy,shrinkage,printing efficiency of green bodies,as well as the microstructure and mechanical properties of sintered ceramic core samples.As the printing angle in the green body increases,the bonding area decreases,surface roughness on the XY plane worsens,shrinkage in the Z direction becomes more pronounced,and the printing efficiency declines.Similarly,an increase in the printing angle in the sintered body leads to a reduction in bending strength.At a printing angle of 30°,the printing time is reduced to half of that at 90°,which improves the molding efficiency.Meanwhile,the obtained bulk density of 1.71 g·cm~(-3),open porosity of 24%,and fiexural strength of 10.6±1 MPa can meet the requirements of sintered ceramic cores.Therefore,designing and optimizing the printing angles can achieve the balance between shrinkage,printing efficiency,and fiexural strength.
基金supported by the Science and Technology Project of China Southern Power Grid Co.,Ltd under Grant 036000KC23090004(GDKJXM20231026).
文摘The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.
文摘The marine propeller typically functions within thefilowfiield generated by a water vehicle.Investigations into the geometric parameters of the propeller are commonly conducted under open‑water conditions as simultaneously simulating both vehicle and propeller holds several computational challenges.While during operation,this propellant device must face several forces like gravity,hydrodynamic load,and centrifugal force,which cause different problems like cavitation and structural failure,etc.Since these issues affect performance,it necessitates comprehensive analysis.In this study,hydrodynamic analysis is performed by using commercial software STAR CCM+.In hydrodynamic analysis,the effect of the rake angles–5°,5°,10°and 15°on hydrodynamic coeffiicients and effiiciency of the DTMB 4119 in the open water is analyzed using Computational Fluid Dynamics(CFD)and the control volume approach.The Shear Stress Transport(SST)k‑ωturbulence model is used in Computational Fluid Dynamics(CFD)simulation.Hydrodynamic analysis reveals that the rake angles 5°and 10°cause the open water effiiciency of David Taylor Model Basin(DTMB)4119 to improve by 0.4 to 1.32%with exception of the rake angles–5°and 15°,which possess different effects on effiiciency.The angle–5°causes a decrease in propeller effiiciency under heavy loading situations(low advance coeffiicient)apart from a minorfiluctuation at light loading conditions(high advance coeffiicient),while the angle 15°produces a drop in effiiciency by higher advance ratios but little variation at lower advance ratios.
基金Supported by National Key R&D Program of China(No.2023YFC2506100)the Changping Key Research Project of the Beijing Natural Science Foundation Program(No.L234016).
文摘AIM:To investigate the role of adipokines in primary open angle glaucoma(POAG)by comparing the levels of these molecules in the aqueous humor among POAG patients and cataract patients with or without metabolic disorders.METHODS:In this cross-sectional study,aqueous humor samples of 22 eyes of POAG patients(POAG group),24 eyes of cataract patients without metabolic disorders(cataract group),and 24 eyes of cataract patients with metabolic disorders(cataract+metabolic disorders group)were assessed for 15 adipokines by Luminex bead-based multiplex array.The correlation between aqueous humor adipokines and clinical indicators of POAG was analyzed and compared across the groups.RESULTS:The analysis revealed that the levels of adiponectin,leptin,adipsin,retinol-binding protein 4(RBP4),angiopoietin-2,angiopoietin-like protein 4(ANGPTL4),chemokine(C-C motif)ligand 2(CCL2),interleukin-8(IL-8),and interleukin-18(IL-18)in the aqueous humor of the POAG group were significantly higher than those in the cataract group.Additionally,the level of angiopoietin-2 in the POAG group was higher than in the cataract+metabolic disorders group.However,no significant correlation was found between the levels of adipokines in the POAG group and intraocular pressure(IOP),severity of POAG,or the use of glaucoma medications.CONCLUSION:This study demonstrates significant differences in aqueous humor adipokine levels between POAG and cataract patients.The findings suggest that the levels of aqueous humor adipokines may reflect the inflammatory states in POAG and systemic metabolic abnormalities.
基金supported in part by the National Defense Basic Scientific Research Program of China(No.JCKY2021603B030)the Shenzhen Fundamental Research Program,China(No.JCYJ20220818102601004)the Science Center Program of National Natural Science Foundation of China(No.62188101)。
文摘Rapid and reliable onboard optimization of bank angle profiles is crucial for mitigating uncertainties during Mars atmospheric entry.This paper presents a neural-network-accelerated methodology for optimizing parametric bank angle profiles in Mars atmospheric entry missions.The methodology includes a universal approach to handling path constraints and a reliable solution method based on the Particle Swarm Optimization(PSO)algorithm.For illustrative purposes,a mission with the objective of maximizing terminal altitude is considered.The original entry optimization problem is converted into optimizing three coefficients for the bank angle profiles with terminal constraints by formulating a parametric Mars entry bank angle profile and constraint handling methods.The parameter optimization problem is addressed using the PSO algorithm,with reliability enhanced by increasing the PSO swarm size.To improve computational efficiency,an enhanced Deep Operator Network(Deep ONet)is used as a dynamics solver to predict terminal states under various bank angle profiles rapidly.Numerical simulations demonstrate that the proposed methodology ensures reliable convergence with a sufficiently large PSO swarm while maintaining high computational efficiency facilitated by the neural-network-based dynamics solver.Compared to the existing methodologies,this methodology offers a streamlined process,the reduced sensitivity to initial guesses,and the improved computational efficiency.
基金supported by the National Natural Science Foundation of China(Grant Nos.52174096 and 52304110).
文摘With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This study investigates the influence of prefabricated crack dip angles on the mechanical properties of anchored rock masses in deep soft rock roadways.By constructing similarity models of NPR(Negative Poisson’s Ratio)and PR(Positive Poisson’s Ratio)anchored solids,biaxial compression experiments under varying crack dip angles were conducted.Strain gauges,3D Digital Image Correlation(3D DIC),and acoustic emission monitoring were employed to systematically analyze the strength characteristics,deformation-damage evolution,and energy dissipation mechanisms of the two types of anchor systems.The results show that:(1)The stress-strain curves of anchored solids with prefabricated cracks exhibit a distinct bimodal characteristic.Compared to PR anchors,NPR anchors show 20%and 23%improvements in peak strength and elastic modulus,respectively,with residual strength enhanced by up to 34%.(2)Owing to high pre-tightening force and large deformation capacity,NPR anchors maintain superior integrity under increasing crack dip angles,demonstrating more uniform free-surface displacement and localized shear-tensile composite crack patterns.(3)Acoustic emission analysis reveals that NPR anchors exhibit higher cumulative energy absorption(300%improvement over PR anchors)and lack low-rate energy development phases,indicating enhanced ductility and impact resistance at high crack dip angles.(4)Crack dip angle critically governs failure mechanisms by modulating the connectivity between shear cracks and prefabricated fissures:bimodal effects dominate at low angles,while vertical tensile crack propagation replaces bimodal behavior at high angles.The study proposes prioritizing NPR anchor cables in deep engineering applications and optimizing support parameters based on crack dip angles to mitigate stress concentration and ensure the long-term stability of surrounding rock.
基金supported by the National Natural Science Foundation ofChina(GrantNo.12402291)the Beijing Natural Science Foundation(No.3244043)the Research Start-up Funds of Hangzhou International Innovation Institute of Beihang University(Grant Nos.2024KQ008,2024KQ062).
文摘This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation frequencies.Results reveal that the eigenfrequencies vary spatially due to distinct oscillation modes occurring at different droplet locations.Notably,the fundamental eigenfrequency decreases with reducing droplet volume,while droplet viscosity exerts minimal influence on this frequency.Prior to the onset of motion,the dynamic contact angle consistently remains between the advancing and receding angles.The inertial forces generated by droplet oscillation are found to be significantly greater than the adhesion forces,indicating that classical static models are inadequate for capturing inertial contributions to droplet motion.These findings offer new insights into the role of oscillatory behavior in influencing the dynamics of droplet motion,and contribute to a more detailed understanding of wind-driven droplet transport phenomena.
基金supported by the Key Research Project of Zhejiang Lab(Grant No.K2022MEOAC01)。
文摘This study introduces the lattice spring model(LSM)to investigate the incline angle of a non-uniform three-segment towed array under steady-state conditions.A numerical model was established,and parametric analysis was conducted to examine the effects of towing speed and cable density on the incline angle.The numerical simulations demonstrate that for a conventional three-segment towed array with heavy vibration-isolation cable and density exceeding that of seawater,the towing speed must exceed 4 kn to maintain the acoustic cable's average incline angle below 10°.To validate the proposed LSM,a 100-meter-long towed array with variable densities was fabricated and tested through lake trials.The experimental results align closely with simulations,confirming LSM as a reliable model for predicting towed array position and posture.The study concludes by analyzing the parallel computing capabilities of LSM and its application in Fluid-Structure Interaction(FSI)problems.The model's precision and parallel computing capabilities make LSM an efficient,reliable tool for analyzing the steady-state behavior of towed systems.
基金the Natural Science Foundation of Hebei Province,China(Grant No.E2022502052)Fundamental Research Funds for the Central Universities,China(Grant No.2022MS081)Fundamental Research Funds for the Central Universities,China(Grant No.2023MS121).
文摘This study explores the influence of rotor blade angle on stall inception in an axial fan by means of numerical simulations grounded in the Reynolds-Averaged Navier-Stokes(RANS)equations and the Realizable k-εturbulence model.By analyzing the temporal behavior of the outlet static pressure,along with the propagation velocity of stall inception,the research identifies distinct patterns in the development of stall.The results reveal that stall inception originates in the second rotor impeller.At a blade angle of 27°,the stall inception follows a modal wave pattern,while in all other cases,it assumes the form of spike-type stall.The flow field associated with spike stall inception demonstrates a relatively uniform gradient in the radial direction,whereas the modal wave stall case displays a distinctive“L”-shaped propagation feature.At blade angles of multiple stall inceptions are observed.-9°and-18°,These phenomena initiate at the blade’s leading edge,propagate along both axial and radial directions,and transition dynamically between single and multiple inception states.
基金Supported by the National Natural Science Foundation of China(No.81770920)Open Project of State Key Laboratory of Ophthalmology(No.303060202400383).
文摘AIM:To explore whether plasma proteins serve as potential therapeutic targets for primary open angle glaucoma(POAG)based on a Mendelian randomization(MR)study.METHODS:Large-scale protein quantitative trait loci(pQTLs)data from the Icelandic deCODE database and two large POAG Genome-Wide Association Study(GWAS)summary datasets were used in this study.Causal associations between plasma proteins and POAG were identified using summary-data-based MR(SMR)analysis and the heterogeneity in dependent instruments(HEIDI)test.Colocalization analysis was then conducted to assess the genetic associations between these two factors.Phenotype-wide MR analysis was performed to validate protein targets as potential drug targets and to evaluate potential side effects.Finally,protein-protein interactions(PPI)were studied,and the Drug-Gene Interaction Database(DGIDb)was used to identify associations between drugs and the identified proteins.RESULTS:Four proteins(SVEP1,TMEM190,ROBO1,and ENPP5)were identified as potential drug targets in this study.Phenome-wide MR analysis showed that SVEP1,ROBO1,and ENPP5 were not associated with adverse effects,while TMEM190 was linked to nerve root and plexus disorders,as well as subarachnoid hemorrhage.Ticagrelor was suggested as a potential new drug for the treatment of glaucoma by regulating SVEP1.CONCLUSION:Four plasma proteins—SVEP1,TMEM190,ROBO1,and ENPP5—are identified as potential therapeutic targets for POAG through an MR approach.Phenome-wide MR analysis reveals that SVEP1,ROBO1,and ENPP5 are not associated with adverse effects,while TMEM190 is linked to nerve root and plexus disorders,as well as subarachnoid hemorrhage.Ticagrelor is proposed as a potential therapeutic drug for glaucoma by regulating SVEP1.These findings highlight the potential of plasma proteins as drug targets for POAG and provide valuable insights for further research.
