This letter compares the clinical efficacy and economic feasibility of the scoliocorrector fatma-UI(SCFUI)with direct vertebral rotation(DVR)in treating adolescent idiopathic scoliosis(AIS).SCFUI has shown promising r...This letter compares the clinical efficacy and economic feasibility of the scoliocorrector fatma-UI(SCFUI)with direct vertebral rotation(DVR)in treating adolescent idiopathic scoliosis(AIS).SCFUI has shown promising results in threedimensional spinal correction,providing superior rotational alignment compared to DVR and achieving significant improvements in coronal and sagittal planes.Additionally,SCFUI’s advanced design reduces risks associated with AIS surgeries and enhances overall patient outcomes.Economic analysis reveals SCFUI as a cost-effective option,potentially lowering long-term healthcare costs by minimizing complications and revisions.Our findings suggest that SCFUI is a viable,innovative approach in AIS treatment,meeting clinical and economic demands in orthopedic care.展开更多
1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-...1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.展开更多
Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind ene...Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind energy applications.In industries,rotational bodies are commonly present in operations,yet this kinetic energy remains untapped.This research explores the energy generation characteristics of two rotational body types,disk-shaped and cylinder-shaped under specific experimental setups.The hardware setup included a direct current(DC)motor driver,power supply,DC generator,mechanical support,and load resistance,while the software setup involved automation testing tools and data logging.Electromagnetic induction was used to harvest energy,and experiments were conducted at room temperature(25℃)with controlled variables like speed and friction.Results showed the disk-shaped body exhibited higher energy efficiency than the cylinder-shaped body,largely due to lower mechanical losses.The disk required only two bearings,while the cylinder required four,resulting in lower bearing losses for the disk.Additionally,the disk experienced only air friction,whereas the cylinder encountered friction from a soft,uneven rubber material,increasing surface contact losses.Under a 40 W resistive load,the disk demonstrated a 17.1%energy loss due to mechanical friction,achieving up to 15.55 J of recycled energy.Conversely,the cylinder body experienced a 48.05%energy loss,delivering only 51.95%of energy to the load.These insights suggest significant potential for designing efficient energy recycling systems in industrial settings,particularly in manufacturing and processing industries where rotational machinery is prevalent.Despite its lower energy density,this system could be beneficially integrated with energy storage solutions,enhancing sustainability in industrial practices.展开更多
Global food production faces enormous challenges in increasing yields while promoting environmental sustainability.A field experiments in the ecotone between the Yangtze River Basin and the HuangHuai-Hai Plain evaluat...Global food production faces enormous challenges in increasing yields while promoting environmental sustainability.A field experiments in the ecotone between the Yangtze River Basin and the HuangHuai-Hai Plain evaluated the effects of changing preceding crop rotation cycles(wheat and rapeseed)on long-term wheat-rice(W)and rapeseed-rice(R)rotation systems.A comprehensive evaluation of crop rotation systems was conducted using life cycle assessment,considering productivity,economic benefits,carbon footprint(CF),and soil health.Compared with fallow-rice rotation(F),alternating rapeseed and wheat rotations increased equivalent yield by 60.4%-82.2%,reduced CF by 0.3%-5.7%,and improved soil health by 0.3%-47.5%.Additionally,adding rapeseed to rotations increased soil nutrient content and raised soil organic carbon stocks by 31.3%-40.5%.The 3R rotation(3-year rapeseed-rice and 1-year wheat-rice)boosted rice yield by 82.2%and annual economic benefits by 84.4%,offering an effective model for optimizing long-term R rotations.Similarly,the 2W rotation(2-year wheat-rice and 1-year rapeseed rice)enhanced rice yield by 70.0% and annual economic benefits by 65.9%,providing a successful example for optimizing long-term W rotations.The 3R rapeseed-based rotation and the 2W wheatbased rotation demonstrated good environmental sustainability.These rotation systems have broad potential in sustainable intensive farming,especially in China and similar regions.展开更多
The dynamic processes responsible for the movement of tropical cyclone Khanun(2017)were studied by analyzing data from the mesoscale WRF model simulation.The simulated motion was induced by the ventilation flow of bot...The dynamic processes responsible for the movement of tropical cyclone Khanun(2017)were studied by analyzing data from the mesoscale WRF model simulation.The simulated motion was induced by the ventilation flow of both the environmentaland asymmetric rotational wind averaged over an area within a radius of 200 km from Khanun's center.The results revealed that during Khanun's intensification period,environmental wind barely changed,whereas the speed and direction of asymmetric rotational wind exhibited significant changes as Khanun's southwestward movement switched to a northwestward movement.The streamfunction analysis revealed that the change in the direction of movement was consistent with the ventilation flow of asymmetric rotational wind across Khanun's center associated with the asymmetric circulation rotation.The cyclonic circulation center rotated counterclockwise,moving from the northeast to the north before and during the rapid intensification period,and exhibited wandering behavior during this period.The rotational rate of asymmetric circulation was quantitatively estimated using the formulation based on the budget of asymmetric rotational kinetic energy.This calculation revealed that the rapid counterclockwise rotation resulted from the conversion of environmental to asymmetric rotational kinetic energy and was related to the horizontal advection of environmental tangential flow.The rotation of the asymmetric circulation displayed a wandering behavior when the dissipation term became significant.The dissipation term plus the conversion from symmetric to asymmetric rotational kinetic energy associated with the advection of symmetric tangential wind by the environmental radial wind led to a slow clockwise rotation of the asymmetric cyclonic center to the north.展开更多
The Bei Dou satellite system(BDS)has progressed with the full operationalization of the secondgeneration regional system(BDS-2)and the third-generation global system(BDS-3).This technology plays a crucial role in dete...The Bei Dou satellite system(BDS)has progressed with the full operationalization of the secondgeneration regional system(BDS-2)and the third-generation global system(BDS-3).This technology plays a crucial role in determining Earth Rotation Parameters(ERPs).In this study,we determine the ERPs based on the observations of BDS-2,BDS-3 and BDS-2+BDS-3,with the time spanning from August18,2022,to August 18,2023.The IERS EOP 20C04 series is used as a reference to evaluate the accuracy of the ERP estimates.We analyze the impact of different numbers of reference stations,polyhedron volumes,observation arc lengths,satellite types,and satellite systems on solving ERPs using BDS-2 and BDS-3 observation data provided by the International GNSS Service(IGS)stations.When selecting a specific satellite type,it is necessary to choose an appropriate observation arc length based on different numbers of reference stations while maximizing the volume of the formed polyhedron to achieve optimal efficiency and accuracy in parameter estimation.When both the number of reference stations and observation arc length are fixed,higher precision of the ERPs can be achieved using observations from MEO than MEO+IGSO and MEO+IGSO+GEO.Moreover,when considering only IGSO and MEO satellites as options for analysis purposes,BDS-3 provides higher accuracy compared to BDS-2.In summary,when using BDS for ERP estimation and MEO satellite observations with the same observation arc length,selecting stations from reference stations with larger polyhedral volumes can significantly improve the efficiency and accuracy of parameter estimation.展开更多
Objective:To clarify the preferences and core demands of professional Master’s students in Tuina at Yunnan University of Chinese Medicine regarding“concentrated”versus“dispersed”rotation schedules in the Tuina de...Objective:To clarify the preferences and core demands of professional Master’s students in Tuina at Yunnan University of Chinese Medicine regarding“concentrated”versus“dispersed”rotation schedules in the Tuina department,as well as their preferred year for primary rotation,providing evidence for optimizing rotation programs and improving the quality of standardized training.Methods:Paper questionnaires,including two multiple-choice questions and one open-ended question,were distributed to 30 professional Tuina Master’s students,completed on site,and collected immediately.Descriptive statistics were used to analyze preference distributions.Results:A total of 30 questionnaires were distributed and 30 valid responses were collected,achieving a 100%response rate.Among them,23 students(76.7%)supported“concentrated training,”while seven students(23.3%)preferred“dispersed training.”Regarding rotation year preference,18 students(60.0%)selected the second year for concentrated Tuina rotations,eight students(26.7%)selected the third year,and four students(13.3%)selected the first year.The core demands supporting concentrated training were“skill continuity,deep involvement in diagnosis and treatment,and smooth mentorship transition,”whereas those supporting dispersed training were“integration of multi-department knowledge,coordination of research time,and avoidance of fatigue from a single department.”Conclusion:Most professional Tuina Master’s students prefer concentrated Tuina rotations in the second year.It is recommended that institutions adopt a“second-year core department concentrated+auxiliary department flexible dispersed”model and establish flexible coordination and feedback mechanisms to balance clinical skill development with individualized growth needs.展开更多
Wheat-maize(WM)and wheat-soybean(WS)double-cropping rotation systems are predominant in the North China Plain,with implications for national agricultural output and sustainability.As rotation systems exert legacy effe...Wheat-maize(WM)and wheat-soybean(WS)double-cropping rotation systems are predominant in the North China Plain,with implications for national agricultural output and sustainability.As rotation systems exert legacy effects on soil health and crop productivity,the role of crop rotation in shaping the root-associated microbiome of the succeeding crops has emerged as a pivotal aspect of crop management research.Here,the effects of the preceding two cycles of WM and WS rotations on the recruitment and filtering of wheat root-associated bacterial communities across wheat developmental stages were investigated.Our results revealed that bacterial community diversity and composition were primarily influenced by compartment and developmental stage,while the preceding rotation systems had a slight but significant effect on wheat root-associated bacterial communities.The co-occurrence networks under WM were more complex in the wheat rhizosphere and rhizoplane,with the operational taxonomic units(OTUs)related to cellulolysis showing greater connectivity.The co-occurrence networks under WS were simple but stable in the rhizosphere and complex in the rhizoplane and endosphere,with the OTUs related to ureolysis and nitrogen fixation showing greater connectivity.While both stochastic and deterministic processes contributed to the assembly of wheat root-associated bacterial communities,the contributions of deterministic processes under WS were 19.4-38.5%higher than those under the WM rotation across the root-associated compartments,indicating the substantial impact of a soybean legacy effect on wheat root selection of microbes.Plant growthpromoting rhizobacteria with the potential to fix nitrogen,produce indole-3-acetic acid,and inhibit diseases such as Betaproteobacteriales,Azospirillales and Dyella sp.,were identified within the OTUs that were consistently enriched across all the wheat root-associated compartments and developmental stages,which were also important predictors of wheat yield.This study elucidates the role of crop rotation in modulating the dynamics of crop root-associated bacterial communities,and underscores the potential of targeted microbiome manipulation for optimizing wheat production and enhancing soil health.展开更多
As a paddy—upland rotation system, tobacco—rice rotation hastypical characteristics in the formation and evolution of soil fertility duringthe tobacco season with dry farming and rice season with water cultivation.T...As a paddy—upland rotation system, tobacco—rice rotation hastypical characteristics in the formation and evolution of soil fertility duringthe tobacco season with dry farming and rice season with water cultivation.To scientifically unveil the soil fertility formation process and grade thesoil fertility in tobacco—rice rotation areas, we collected 372 soil samplesfrom 11 tobacco stations (Haotang, Aoquan, Chengjiao, Renyi, Fangyuan,Anping, Huangsha, Taiping, Tushi, Dashiqiao, and Baimangying) in thetypical tobacco—rice rotation areas of Chenzhou and Yongzhou in SouthernHunan. The physical, chemical, and biological indicators of the soil sampleswere measured, and the tobacco and rice yields of each tobacco stationwere investigated. Machine learning was employed to screen the keyindicators influencing the tobacco yield, and a comprehensive numericalanalysis method combining principal component analysis and discriminantanalysis were adopted to cluster the sampling points, analyze their fertilityformation processes, and grade the soil fertility. The results showed thatclay content, available phosphorus, plow layer depth, slit-to-clay ratio, totalnitrogen, basal respiration, and organic carbon were identified as seven keyindicators influencing the tobacco yield. The results of the comprehensivenumerical analysis predicted two main processes involved in the formationof soil fertility in tobacco—rice rotation areas. One was the soil maturationprocess related to soil carbon and nitrogen cycling, and the other was theprocess of changes in soil physical properties such as clay content and slitto-clay ratio. According to the established soil fertility grading methodfor tobacco—rice rotation areas, the soil fertility of 11 tobacco stationswas graded. The results showed that the soil fertility was high in Haotang,Aoquan, Renyi, and Dashiqiao, medium in Huangsha and Tushi, and low inAnping, Baimangying, and Taiping. The tobacco and rice yields confirmedthat this grading standard can be effectively applied to the grading of soilfertility in the tobacco—rice rotation areas in Southern Hunan and canprovide a scientific basis for soil management in tobacco—rice rotation.展开更多
Active matter exhibits collective motions at various scales.Geometric confinement has been identified as an effective way to control and manipulate active fluids,with much attention given to external factors.However,t...Active matter exhibits collective motions at various scales.Geometric confinement has been identified as an effective way to control and manipulate active fluids,with much attention given to external factors.However,the impact of the inherent properties of active particles on collective motion under confined conditions remains elusive.Here,we use a highly tunable active nematics model to study active systems under confinement,focusing on the effect of the self-driven speed of active particles.We identify three distinct states characterized by unique particle and flow fields within confined active nematic systems,among which circular rotation emerges as a collective motion involving rotational movement in both particle and flow fields.The theoretical phase diagram shows that increasing the self-driven speed of active particles significantly enhances the region of the circular rotation state and improves its stability.Our results provide insights into the formation of high quality vortices in confined active nematic systems.展开更多
Diversifying crop rotation aims to balance production and ecological concerns.However,yield and water use efficiency(WUE)of crop in diversified rotation systems have not been well documented,especially under limited i...Diversifying crop rotation aims to balance production and ecological concerns.However,yield and water use efficiency(WUE)of crop in diversified rotation systems have not been well documented,especially under limited irrigation.Here,we conducted a 6-year experiment with five treatments:1)wheatmaize cropping system(WM),as control;2)WMME,spring maize→WM rotation;3)WMML,spring millet→WM rotation;4)WMMP,spring peanut→WM rotation;and 5)WMMS,spring soybean→WM rotation,to explore how diversified rotations affected yield and WUE of wheat.Results showed that approximately 60% higher precipitation during wheat growing season in Cycle 1(2015-2017)resulted in yield increases by 33.8%-55.7% compared to those in Cycle 2(2017-2019)and Cycle3(2019-2021).Grain yield and WUE of wheat were 16.7% and 9.6% higher in Cycle 1,81.5% and 86.8% higher in Cycle 2,and 56.1% and 78.7% higher in Cycle 3 on average in diversified rotations compared to those in WM,respectively.Further analysis revealed that spike number and aboveground biomass were the main contributors to the increments,which can be explained by the increased evapotranspiration during the middle-late wheat growth stages(e.g.,regreening,jointing,and anthesis)in diversified rotations.In general,diversified rotations enhanced synchronization of soil water supply with crop water demand by affecting the spatiotemporal dynamics of soil moisture under varied precipitation conditions,thereby increasing yield and WUE of wheat.Hence,diversified spring crops→WM rotations offer a sustainable and efficient strategy for enhancing wheat production and water conservation in dry areas.展开更多
Vorticity is locally generated on a boundary at a rate measured by the boundary vorticity flux(BVF),which can be further decomposed into the sum of the orbital rotation and the generalized spin(specifically,the sum of...Vorticity is locally generated on a boundary at a rate measured by the boundary vorticity flux(BVF),which can be further decomposed into the sum of the orbital rotation and the generalized spin(specifically,the sum of shear and streaming vorticity)under the field description.For an incompressible viscous flow interacting with a stationary wall,the full expressions of the boundary fluxes of the orbital rotation and the spin are derived,for the first time,to elucidate their boundary creation mechanisms.Then,these new findings are successfully extended to the study of the boundary enstrophy dynamics,as well as the Lyman vorticity dynamics as an alternative interpretation to the boundary vorticity dynamics.Interestingly,it is found that the boundary coupling of the longitudinal and transverse processes is only embodied in the boundary spin flux,which is definitely not responsible for the generation of the boundary orbital-rotation flux.In addition,the boundary fluxes of enstrophy are directly associated with the boundary source of the second principal invariant of the velocity gradient tensor(VGT)and the two quadratic forms representing the spin-geometry interaction.The present exposition provides a new perspective and an additional dimension for understanding the vorticity dynamics on boundaries,which could be valuable in clarifying the formation mechanisms of near-wall coherent structures and flow noise at the fundamental level.展开更多
The paper is devoted to establishing the long-time behavior of solutions to the extensible beam equation with rotational inertia and nonlocal strong damping.Within the theory of asymptotical smoothness,we investigate ...The paper is devoted to establishing the long-time behavior of solutions to the extensible beam equation with rotational inertia and nonlocal strong damping.Within the theory of asymptotical smoothness,we investigate the existence of the attractor by using the contractive function method and more detailed estimates.展开更多
Ceramic hollow spheres have great potential for deep-sea applications.However,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow spheres.To solv...Ceramic hollow spheres have great potential for deep-sea applications.However,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow spheres.To solve this problem,in this work,we developed a biaxial rotation grouting process for deep-sea ceramic hollow buoyancy spheres,which improves the drawbacks of the traditional rotary grouting method that results in poor wall thickness uniformity of the hollow spheres due to its irregular rotational processing.In this paper,an experimental study was carried out to investigate the effects of different rotational methods,rotational speeds,rotational time,solid phase content,etc.on the wall thickness uniformity of ceramic hollow spheres.The results show that the hollow floating balls prepared by the biaxial rotation method have the lowest wall thickness standard deviation(0.04)when the rotation speed is 60 rpm,the molding time is 8 min,and the solid phase content is 70 wt%.After the hydrostatic pressure test of 120 MPa,the hydrostatic compressive strength of hollow spheres prepared by the biaxial rotation method was increased by 31.67%compared with that of the traditional process.展开更多
With the popularity of the digital human body,monocular three-dimensional(3D)face reconstruction is widely used in fields such as animation and face recognition.Although current methods trained using single-view image...With the popularity of the digital human body,monocular three-dimensional(3D)face reconstruction is widely used in fields such as animation and face recognition.Although current methods trained using single-view image sets perform well in monocular 3D face reconstruction tasks,they tend to rely on the constraints of the a priori model or the appearance conditions of the input images,fundamentally because of the inability to propose an effective method to reduce the effects of two-dimensional(2D)ambiguity.To solve this problem,we developed an unsupervised training framework for monocular face 3D reconstruction using rotational cycle consistency.Specifically,to learn more accurate facial information,we first used an autoencoder to factor the input images and applied these factors to generate normalized frontal views.We then proceeded through a differentiable renderer to use rotational consistency to continuously perceive refinement.Our method provided implicit multi-view consistency constraints on the pose and depth information estimation of the input face,and the performance was accurate and robust in the presence of large variations in expression and pose.In the benchmark tests,our method performed more stably and realistically than other methods that used 3D face reconstruction in monocular 2D images.展开更多
We study the motion of an inertial microswimmer in a non-Newtonian environment with a finite memory and present the theoretical realization of an unexpected transition from random self-propulsion to rotational(circula...We study the motion of an inertial microswimmer in a non-Newtonian environment with a finite memory and present the theoretical realization of an unexpected transition from random self-propulsion to rotational(circular or elliptical)motion.Further,the rotational motion of the swimmer is followed by spontaneous local directional reversal,yet with a steady-state angular diffusion.Moreover,the advent of this behaviour is observed in the oscillatory regime of the inertia-memory parameter space of the dynamics.We quantify this unconventional rotational motion of the microswimmer by measuring the time evolution of the direction of its instantaneous velocity or orientation.By solving the generalized Langevin model of non-Markovian dynamics of an inertial active Ornstein–Uhlenbeck particle,we show that the emergence of the rotational(circular or elliptical)trajectory is due to the presence of both inertial motion and memory in the environment.展开更多
Management of patients with acute hemorrhage requires addressing the source of bleeding,replenishing blood volume,and addressing any coagulopathy that may be present.Assessing coagulopathy and predicting blood require...Management of patients with acute hemorrhage requires addressing the source of bleeding,replenishing blood volume,and addressing any coagulopathy that may be present.Assessing coagulopathy and predicting blood requirements in real-time in patients experiencing ongoing bleeding can pose substantial challenges.In these patients,transfusion concepts based on ratios do not effectively address coagulopathy or reduce mortality.Moreover,ratio-based concepts do not stop bleeding;instead,they just give physicians more time to identify the bleeding source and plan management strategies.In clinical practice,standard laboratory coagulation tests(SLCT)are frequently used to assess various aspects of blood clotting.However,these tests may not always offer a comprehensive under-standing of clinically significant coagulopathy and the severity of blood loss.Furthermore,the SLCT have a considerable turnaround time,which may not be ideal for making prompt clinical decisions.In recent years,there has been a growing interest in point-of-care viscoelastic assays like rotational thromboelast-ometry,which provide real-time,dynamic information about clot formation and dissolution.展开更多
This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally...This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally graded sandwich rectangular plate in a thermal environment are derived using classical thin plate theory and Hamilton’s principle,considering geometric nonlinearity,temperature-dependent material properties,and power law distribution of components through the thickness.With cantilever boundary conditions,the flexural nonlinear differential equations of the rectangular sandwich plate are obtained via the Galerkin method.Since the natural vibration differential equations exhibit nonlinear characteristics,the multiscale method is employed to derive the expression for nonlinear natural frequency.An example analysis reveals how the natural frequency of a functionally graded sandwich rectangular plate varies with rotational speed and temperature.Results show that the nonlinear/linear frequency ratio increases with rotational angular velocity Ω and thickness-to-length ratio h/a,follows a cosine-like periodic pattern with the setting angle,and shows a sharp decrease followed by a rapid increase with increasing width-to-length ratio b/a.The derived analytical solutions for nonlinear frequency provide valuable insights for assessing the dynamic characteristics of functionally graded structures.展开更多
Rotational feeding combined with shift feeding electrochemical trepanning(RF-SF ECTr)is an effective method for machining aeroengine blisks.However,given the variable relative motion of the electrodes and the complex ...Rotational feeding combined with shift feeding electrochemical trepanning(RF-SF ECTr)is an effective method for machining aeroengine blisks.However,given the variable relative motion of the electrodes and the complex flow channels around the bending and twisting blades,the accessibility and uniformity of the flow field are poor in blisk RF-SF ECTr using the traditional electrolyte supply(TES)mode,resulting in poor machining stability and low machining efficiency.To improve the distribution of the flow field,a new multi-channel electrolyte supply(MCES)mode is proposed for blisk RF-SF ECTr,in which the position and volume of the electrolyte supply are controlled effectively by setting multiple inlet channels in the liquid inlet area.A flow-field simulation comparison between TES and MCES shows that better accessibility and uniformity of the flow-field distribution are achieved under MCES.To clarify further the flow-field distribution characteristics under RF-SF ECTr,a series of flow-field simulations was conducted at different machining depths.Based on the obtained dynamic change law for the flow field,to enhance further its uniformity and accessibility,a global coverage strategy for the electrolyte supply and a flow-field structure optimization method for MCES are proposed,which involve optimizing the number,diameter,and location of the inlet channels.After many simulations,the optimal MCES structure was achieved whereby the electrolyte covers all positions effectively in the processing area.To verify the proposed method as effective and correct,a series of RF-SF ECTr experiments was carried out.Under the optimized MCES mode,the feeding rate was increased from 0.8 mm/min with the TES mode to 2.0 mm/min,and the processing stability and efficiency were improved significantly.The methods presented here offer an effective guide for flow-field optimization when machining other components with complex spatial structures.展开更多
Recent studies have increasingly identified extended main sequence turn-off(e MSTO)phenomena in Galactic open clusters,yet the number of such clusters with sufficient spectroscopic information for member stars remains...Recent studies have increasingly identified extended main sequence turn-off(e MSTO)phenomena in Galactic open clusters,yet the number of such clusters with sufficient spectroscopic information for member stars remains limited.Unlike most studies that rely on fitting isochrones based on color–magnitude diagram(CMD)morphology to account for varying rotational velocities,our approach leverages LAMOST spectral data to compute actual rotational velocity distributions for confirmed cluster members,along with parameters such as metallicity,differential extinction,and rotational inclination,to utilize PARSEC isochrones for fitting the cluster CMDs.We systematically surveyed all known Galactic open clusters and selected 12 clusters where rotational velocity distributions could be reliably calculated for detailed fitting.Our results successfully reproduced the eMSTO phenomenon observed in these clusters.For the majority of clusters,considering only differential extinction and variations in rotational velocity adequately explains the position and morphology of the MSTO.For some intermediate-age clusters,incorporating rotational inclination additionally accounts for the broadening of the MSTO.This study underscores the importance of spectroscopic data in understanding eMSTO phenomena and provides a probable explanation for interpreting the combined effects of differential extinction,rotation,and inclination on the CMDs of Galactic open clusters.展开更多
文摘This letter compares the clinical efficacy and economic feasibility of the scoliocorrector fatma-UI(SCFUI)with direct vertebral rotation(DVR)in treating adolescent idiopathic scoliosis(AIS).SCFUI has shown promising results in threedimensional spinal correction,providing superior rotational alignment compared to DVR and achieving significant improvements in coronal and sagittal planes.Additionally,SCFUI’s advanced design reduces risks associated with AIS surgeries and enhances overall patient outcomes.Economic analysis reveals SCFUI as a cost-effective option,potentially lowering long-term healthcare costs by minimizing complications and revisions.Our findings suggest that SCFUI is a viable,innovative approach in AIS treatment,meeting clinical and economic demands in orthopedic care.
基金supported by the National Natural Science Foundation of China(No.52061135101 and 52001078)the German Research Foundation(DFG,No.448318292)+3 种基金the Technology Innovation Guidance Special Foundation of Shaanxi Province(No.2023GXLH-085)the Fundamental Research Funds for the Central Universities(No.D5000240161)the Project of Key areas of innovation team in Shaanxi Province(No.2024RS-CXTD-20)The author Yingchun Xie thanks the support from the National Key R&D Program(No.2023YFE0108000).
文摘1.Introduction.Cold Spray(CS)is a highly advanced solid-state metal depo-sition process that was first developed in the 1980s.This innovative technique involves the high-speed(300-1200 m/s)impact deposition of micron-sized particles(5-50μm)to fabricate coatings[1-3].CS has been extensively used in a variety of coating applications,such as aerospace,automotive,energy,medical,marine,and others,to provide protection against high temperatures,corrosion,erosion,oxidation,and chemicals[4,5].Nowadays,the technical interest in CS is twofold:(i)as a repair process for damaged components,and(ii)as a solid-state additive manufacturing process.Compared to other fusion-based additive manufacturing(AM)technologies,Cold Spray Additive Manufacturing(CSAM)is a new member of the AM family that can enable the fabrication of deposits without undergoing melting.The chemical composition has been largely preserved from the powder to the deposit due to the minimal oxidation.The significant advantages of CSAM over other additive manufacturing processes include a high production rate,unlimited deposition size,high flexibility,and suitability for repairing damaged parts.
基金The APC was funded by Research Management Center, Multimedia University, Malaysia.
文摘Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind energy applications.In industries,rotational bodies are commonly present in operations,yet this kinetic energy remains untapped.This research explores the energy generation characteristics of two rotational body types,disk-shaped and cylinder-shaped under specific experimental setups.The hardware setup included a direct current(DC)motor driver,power supply,DC generator,mechanical support,and load resistance,while the software setup involved automation testing tools and data logging.Electromagnetic induction was used to harvest energy,and experiments were conducted at room temperature(25℃)with controlled variables like speed and friction.Results showed the disk-shaped body exhibited higher energy efficiency than the cylinder-shaped body,largely due to lower mechanical losses.The disk required only two bearings,while the cylinder required four,resulting in lower bearing losses for the disk.Additionally,the disk experienced only air friction,whereas the cylinder encountered friction from a soft,uneven rubber material,increasing surface contact losses.Under a 40 W resistive load,the disk demonstrated a 17.1%energy loss due to mechanical friction,achieving up to 15.55 J of recycled energy.Conversely,the cylinder body experienced a 48.05%energy loss,delivering only 51.95%of energy to the load.These insights suggest significant potential for designing efficient energy recycling systems in industrial settings,particularly in manufacturing and processing industries where rotational machinery is prevalent.Despite its lower energy density,this system could be beneficially integrated with energy storage solutions,enhancing sustainability in industrial practices.
基金supported by the National Natural Science Foundation of China(31971855)the Agricultural Science and Technology Innovation Project of the Chinese Academy of Agricultural Science(CAAS-ASTIP-2021-OCRI)+2 种基金the Hubei Provincial Natural Science Foundation of China(2024AFB442)the Wuhan Knowledge Innovation Special Program(2023020201020400)the China Agriculture Research System(CARS-12)。
文摘Global food production faces enormous challenges in increasing yields while promoting environmental sustainability.A field experiments in the ecotone between the Yangtze River Basin and the HuangHuai-Hai Plain evaluated the effects of changing preceding crop rotation cycles(wheat and rapeseed)on long-term wheat-rice(W)and rapeseed-rice(R)rotation systems.A comprehensive evaluation of crop rotation systems was conducted using life cycle assessment,considering productivity,economic benefits,carbon footprint(CF),and soil health.Compared with fallow-rice rotation(F),alternating rapeseed and wheat rotations increased equivalent yield by 60.4%-82.2%,reduced CF by 0.3%-5.7%,and improved soil health by 0.3%-47.5%.Additionally,adding rapeseed to rotations increased soil nutrient content and raised soil organic carbon stocks by 31.3%-40.5%.The 3R rotation(3-year rapeseed-rice and 1-year wheat-rice)boosted rice yield by 82.2%and annual economic benefits by 84.4%,offering an effective model for optimizing long-term R rotations.Similarly,the 2W rotation(2-year wheat-rice and 1-year rapeseed rice)enhanced rice yield by 70.0% and annual economic benefits by 65.9%,providing a successful example for optimizing long-term W rotations.The 3R rapeseed-based rotation and the 2W wheatbased rotation demonstrated good environmental sustainability.These rotation systems have broad potential in sustainable intensive farming,especially in China and similar regions.
基金supported by the National Natural Science Foundation of China(Grant No.41930967)。
文摘The dynamic processes responsible for the movement of tropical cyclone Khanun(2017)were studied by analyzing data from the mesoscale WRF model simulation.The simulated motion was induced by the ventilation flow of both the environmentaland asymmetric rotational wind averaged over an area within a radius of 200 km from Khanun's center.The results revealed that during Khanun's intensification period,environmental wind barely changed,whereas the speed and direction of asymmetric rotational wind exhibited significant changes as Khanun's southwestward movement switched to a northwestward movement.The streamfunction analysis revealed that the change in the direction of movement was consistent with the ventilation flow of asymmetric rotational wind across Khanun's center associated with the asymmetric circulation rotation.The cyclonic circulation center rotated counterclockwise,moving from the northeast to the north before and during the rapid intensification period,and exhibited wandering behavior during this period.The rotational rate of asymmetric circulation was quantitatively estimated using the formulation based on the budget of asymmetric rotational kinetic energy.This calculation revealed that the rapid counterclockwise rotation resulted from the conversion of environmental to asymmetric rotational kinetic energy and was related to the horizontal advection of environmental tangential flow.The rotation of the asymmetric circulation displayed a wandering behavior when the dissipation term became significant.The dissipation term plus the conversion from symmetric to asymmetric rotational kinetic energy associated with the advection of symmetric tangential wind by the environmental radial wind led to a slow clockwise rotation of the asymmetric cyclonic center to the north.
基金received financial support from the National Natural Science Foundation of China(Grant No.42030105,No.42204006,No.42274011,No.42304095)Funded by State Key Laboratory of Geo-Information Engineering and Key Laboratory of Surveying and Mapping Science and Geospatial Information Technology of MNR,CASM(Grant No.2024-01-01)+2 种基金Open Fund of Hubei Luojia Laboratory(Grant No.230100020,230100019)the China Postdoctoral Science Foundation(Certificate Number:2023M743580)the Key Project of Natural Science Research in Universities of Anhui Province(No.2023AH051634)。
文摘The Bei Dou satellite system(BDS)has progressed with the full operationalization of the secondgeneration regional system(BDS-2)and the third-generation global system(BDS-3).This technology plays a crucial role in determining Earth Rotation Parameters(ERPs).In this study,we determine the ERPs based on the observations of BDS-2,BDS-3 and BDS-2+BDS-3,with the time spanning from August18,2022,to August 18,2023.The IERS EOP 20C04 series is used as a reference to evaluate the accuracy of the ERP estimates.We analyze the impact of different numbers of reference stations,polyhedron volumes,observation arc lengths,satellite types,and satellite systems on solving ERPs using BDS-2 and BDS-3 observation data provided by the International GNSS Service(IGS)stations.When selecting a specific satellite type,it is necessary to choose an appropriate observation arc length based on different numbers of reference stations while maximizing the volume of the formed polyhedron to achieve optimal efficiency and accuracy in parameter estimation.When both the number of reference stations and observation arc length are fixed,higher precision of the ERPs can be achieved using observations from MEO than MEO+IGSO and MEO+IGSO+GEO.Moreover,when considering only IGSO and MEO satellites as options for analysis purposes,BDS-3 provides higher accuracy compared to BDS-2.In summary,when using BDS for ERP estimation and MEO satellite observations with the same observation arc length,selecting stations from reference stations with larger polyhedral volumes can significantly improve the efficiency and accuracy of parameter estimation.
文摘Objective:To clarify the preferences and core demands of professional Master’s students in Tuina at Yunnan University of Chinese Medicine regarding“concentrated”versus“dispersed”rotation schedules in the Tuina department,as well as their preferred year for primary rotation,providing evidence for optimizing rotation programs and improving the quality of standardized training.Methods:Paper questionnaires,including two multiple-choice questions and one open-ended question,were distributed to 30 professional Tuina Master’s students,completed on site,and collected immediately.Descriptive statistics were used to analyze preference distributions.Results:A total of 30 questionnaires were distributed and 30 valid responses were collected,achieving a 100%response rate.Among them,23 students(76.7%)supported“concentrated training,”while seven students(23.3%)preferred“dispersed training.”Regarding rotation year preference,18 students(60.0%)selected the second year for concentrated Tuina rotations,eight students(26.7%)selected the third year,and four students(13.3%)selected the first year.The core demands supporting concentrated training were“skill continuity,deep involvement in diagnosis and treatment,and smooth mentorship transition,”whereas those supporting dispersed training were“integration of multi-department knowledge,coordination of research time,and avoidance of fatigue from a single department.”Conclusion:Most professional Tuina Master’s students prefer concentrated Tuina rotations in the second year.It is recommended that institutions adopt a“second-year core department concentrated+auxiliary department flexible dispersed”model and establish flexible coordination and feedback mechanisms to balance clinical skill development with individualized growth needs.
基金the National Natural Science Foundation of China(42107339)the China Agriculture Research System(CARS-04)。
文摘Wheat-maize(WM)and wheat-soybean(WS)double-cropping rotation systems are predominant in the North China Plain,with implications for national agricultural output and sustainability.As rotation systems exert legacy effects on soil health and crop productivity,the role of crop rotation in shaping the root-associated microbiome of the succeeding crops has emerged as a pivotal aspect of crop management research.Here,the effects of the preceding two cycles of WM and WS rotations on the recruitment and filtering of wheat root-associated bacterial communities across wheat developmental stages were investigated.Our results revealed that bacterial community diversity and composition were primarily influenced by compartment and developmental stage,while the preceding rotation systems had a slight but significant effect on wheat root-associated bacterial communities.The co-occurrence networks under WM were more complex in the wheat rhizosphere and rhizoplane,with the operational taxonomic units(OTUs)related to cellulolysis showing greater connectivity.The co-occurrence networks under WS were simple but stable in the rhizosphere and complex in the rhizoplane and endosphere,with the OTUs related to ureolysis and nitrogen fixation showing greater connectivity.While both stochastic and deterministic processes contributed to the assembly of wheat root-associated bacterial communities,the contributions of deterministic processes under WS were 19.4-38.5%higher than those under the WM rotation across the root-associated compartments,indicating the substantial impact of a soybean legacy effect on wheat root selection of microbes.Plant growthpromoting rhizobacteria with the potential to fix nitrogen,produce indole-3-acetic acid,and inhibit diseases such as Betaproteobacteriales,Azospirillales and Dyella sp.,were identified within the OTUs that were consistently enriched across all the wheat root-associated compartments and developmental stages,which were also important predictors of wheat yield.This study elucidates the role of crop rotation in modulating the dynamics of crop root-associated bacterial communities,and underscores the potential of targeted microbiome manipulation for optimizing wheat production and enhancing soil health.
文摘As a paddy—upland rotation system, tobacco—rice rotation hastypical characteristics in the formation and evolution of soil fertility duringthe tobacco season with dry farming and rice season with water cultivation.To scientifically unveil the soil fertility formation process and grade thesoil fertility in tobacco—rice rotation areas, we collected 372 soil samplesfrom 11 tobacco stations (Haotang, Aoquan, Chengjiao, Renyi, Fangyuan,Anping, Huangsha, Taiping, Tushi, Dashiqiao, and Baimangying) in thetypical tobacco—rice rotation areas of Chenzhou and Yongzhou in SouthernHunan. The physical, chemical, and biological indicators of the soil sampleswere measured, and the tobacco and rice yields of each tobacco stationwere investigated. Machine learning was employed to screen the keyindicators influencing the tobacco yield, and a comprehensive numericalanalysis method combining principal component analysis and discriminantanalysis were adopted to cluster the sampling points, analyze their fertilityformation processes, and grade the soil fertility. The results showed thatclay content, available phosphorus, plow layer depth, slit-to-clay ratio, totalnitrogen, basal respiration, and organic carbon were identified as seven keyindicators influencing the tobacco yield. The results of the comprehensivenumerical analysis predicted two main processes involved in the formationof soil fertility in tobacco—rice rotation areas. One was the soil maturationprocess related to soil carbon and nitrogen cycling, and the other was theprocess of changes in soil physical properties such as clay content and slitto-clay ratio. According to the established soil fertility grading methodfor tobacco—rice rotation areas, the soil fertility of 11 tobacco stationswas graded. The results showed that the soil fertility was high in Haotang,Aoquan, Renyi, and Dashiqiao, medium in Huangsha and Tushi, and low inAnping, Baimangying, and Taiping. The tobacco and rice yields confirmedthat this grading standard can be effectively applied to the grading of soilfertility in the tobacco—rice rotation areas in Southern Hunan and canprovide a scientific basis for soil management in tobacco—rice rotation.
基金supported by the National Key Research and Development Program of China under Grant No.2022YFA1405000Innovation Program for Quantum Science and Technology under Grant No.2024ZD0300101the National Natural Science Foundation of China under Grant Nos.12274212,12174184,12347102。
文摘Active matter exhibits collective motions at various scales.Geometric confinement has been identified as an effective way to control and manipulate active fluids,with much attention given to external factors.However,the impact of the inherent properties of active particles on collective motion under confined conditions remains elusive.Here,we use a highly tunable active nematics model to study active systems under confinement,focusing on the effect of the self-driven speed of active particles.We identify three distinct states characterized by unique particle and flow fields within confined active nematic systems,among which circular rotation emerges as a collective motion involving rotational movement in both particle and flow fields.The theoretical phase diagram shows that increasing the self-driven speed of active particles significantly enhances the region of the circular rotation state and improves its stability.Our results provide insights into the formation of high quality vortices in confined active nematic systems.
基金supported by the National Natural Science Foundation of China(32172125 and U21A20218)。
文摘Diversifying crop rotation aims to balance production and ecological concerns.However,yield and water use efficiency(WUE)of crop in diversified rotation systems have not been well documented,especially under limited irrigation.Here,we conducted a 6-year experiment with five treatments:1)wheatmaize cropping system(WM),as control;2)WMME,spring maize→WM rotation;3)WMML,spring millet→WM rotation;4)WMMP,spring peanut→WM rotation;and 5)WMMS,spring soybean→WM rotation,to explore how diversified rotations affected yield and WUE of wheat.Results showed that approximately 60% higher precipitation during wheat growing season in Cycle 1(2015-2017)resulted in yield increases by 33.8%-55.7% compared to those in Cycle 2(2017-2019)and Cycle3(2019-2021).Grain yield and WUE of wheat were 16.7% and 9.6% higher in Cycle 1,81.5% and 86.8% higher in Cycle 2,and 56.1% and 78.7% higher in Cycle 3 on average in diversified rotations compared to those in WM,respectively.Further analysis revealed that spike number and aboveground biomass were the main contributors to the increments,which can be explained by the increased evapotranspiration during the middle-late wheat growth stages(e.g.,regreening,jointing,and anthesis)in diversified rotations.In general,diversified rotations enhanced synchronization of soil water supply with crop water demand by affecting the spatiotemporal dynamics of soil moisture under varied precipitation conditions,thereby increasing yield and WUE of wheat.Hence,diversified spring crops→WM rotations offer a sustainable and efficient strategy for enhancing wheat production and water conservation in dry areas.
基金Project supported by the National Natural Science Foundation of China(No.12402262)。
文摘Vorticity is locally generated on a boundary at a rate measured by the boundary vorticity flux(BVF),which can be further decomposed into the sum of the orbital rotation and the generalized spin(specifically,the sum of shear and streaming vorticity)under the field description.For an incompressible viscous flow interacting with a stationary wall,the full expressions of the boundary fluxes of the orbital rotation and the spin are derived,for the first time,to elucidate their boundary creation mechanisms.Then,these new findings are successfully extended to the study of the boundary enstrophy dynamics,as well as the Lyman vorticity dynamics as an alternative interpretation to the boundary vorticity dynamics.Interestingly,it is found that the boundary coupling of the longitudinal and transverse processes is only embodied in the boundary spin flux,which is definitely not responsible for the generation of the boundary orbital-rotation flux.In addition,the boundary fluxes of enstrophy are directly associated with the boundary source of the second principal invariant of the velocity gradient tensor(VGT)and the two quadratic forms representing the spin-geometry interaction.The present exposition provides a new perspective and an additional dimension for understanding the vorticity dynamics on boundaries,which could be valuable in clarifying the formation mechanisms of near-wall coherent structures and flow noise at the fundamental level.
基金Supported by the National Natural Science Foundation of China(Grant Nos.1210150211961059)the University Innovation Project of Gansu Province(Grant No.2023B-062).
文摘The paper is devoted to establishing the long-time behavior of solutions to the extensible beam equation with rotational inertia and nonlocal strong damping.Within the theory of asymptotical smoothness,we investigate the existence of the attractor by using the contractive function method and more detailed estimates.
基金Funded by the Key Research and Development Program of Shandong Province(No.2020JMRH0101)。
文摘Ceramic hollow spheres have great potential for deep-sea applications.However,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow spheres.To solve this problem,in this work,we developed a biaxial rotation grouting process for deep-sea ceramic hollow buoyancy spheres,which improves the drawbacks of the traditional rotary grouting method that results in poor wall thickness uniformity of the hollow spheres due to its irregular rotational processing.In this paper,an experimental study was carried out to investigate the effects of different rotational methods,rotational speeds,rotational time,solid phase content,etc.on the wall thickness uniformity of ceramic hollow spheres.The results show that the hollow floating balls prepared by the biaxial rotation method have the lowest wall thickness standard deviation(0.04)when the rotation speed is 60 rpm,the molding time is 8 min,and the solid phase content is 70 wt%.After the hydrostatic pressure test of 120 MPa,the hydrostatic compressive strength of hollow spheres prepared by the biaxial rotation method was increased by 31.67%compared with that of the traditional process.
基金Supported by Science and Technology Department Major Innovation Special Fund of Hubei Province of China(2020BAB116)。
文摘With the popularity of the digital human body,monocular three-dimensional(3D)face reconstruction is widely used in fields such as animation and face recognition.Although current methods trained using single-view image sets perform well in monocular 3D face reconstruction tasks,they tend to rely on the constraints of the a priori model or the appearance conditions of the input images,fundamentally because of the inability to propose an effective method to reduce the effects of two-dimensional(2D)ambiguity.To solve this problem,we developed an unsupervised training framework for monocular face 3D reconstruction using rotational cycle consistency.Specifically,to learn more accurate facial information,we first used an autoencoder to factor the input images and applied these factors to generate normalized frontal views.We then proceeded through a differentiable renderer to use rotational consistency to continuously perceive refinement.Our method provided implicit multi-view consistency constraints on the pose and depth information estimation of the input face,and the performance was accurate and robust in the presence of large variations in expression and pose.In the benchmark tests,our method performed more stably and realistically than other methods that used 3D face reconstruction in monocular 2D images.
基金the 8th Statphysics Community Meeting(ICTS/ISPCM2023/02)during which we had lots of fruitful discussionsMS acknowledges the start-up grant from UGC,SERB-SURE grant(SUR/2022/000377),CRG grant(CRG/2023/002026)from DST,Govt.of India for the financial support。
文摘We study the motion of an inertial microswimmer in a non-Newtonian environment with a finite memory and present the theoretical realization of an unexpected transition from random self-propulsion to rotational(circular or elliptical)motion.Further,the rotational motion of the swimmer is followed by spontaneous local directional reversal,yet with a steady-state angular diffusion.Moreover,the advent of this behaviour is observed in the oscillatory regime of the inertia-memory parameter space of the dynamics.We quantify this unconventional rotational motion of the microswimmer by measuring the time evolution of the direction of its instantaneous velocity or orientation.By solving the generalized Langevin model of non-Markovian dynamics of an inertial active Ornstein–Uhlenbeck particle,we show that the emergence of the rotational(circular or elliptical)trajectory is due to the presence of both inertial motion and memory in the environment.
文摘Management of patients with acute hemorrhage requires addressing the source of bleeding,replenishing blood volume,and addressing any coagulopathy that may be present.Assessing coagulopathy and predicting blood requirements in real-time in patients experiencing ongoing bleeding can pose substantial challenges.In these patients,transfusion concepts based on ratios do not effectively address coagulopathy or reduce mortality.Moreover,ratio-based concepts do not stop bleeding;instead,they just give physicians more time to identify the bleeding source and plan management strategies.In clinical practice,standard laboratory coagulation tests(SLCT)are frequently used to assess various aspects of blood clotting.However,these tests may not always offer a comprehensive under-standing of clinically significant coagulopathy and the severity of blood loss.Furthermore,the SLCT have a considerable turnaround time,which may not be ideal for making prompt clinical decisions.In recent years,there has been a growing interest in point-of-care viscoelastic assays like rotational thromboelast-ometry,which provide real-time,dynamic information about clot formation and dissolution.
基金supported by the National Natural Science Foundation of China(No.11772090).
文摘This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally graded sandwich rectangular plate in a thermal environment are derived using classical thin plate theory and Hamilton’s principle,considering geometric nonlinearity,temperature-dependent material properties,and power law distribution of components through the thickness.With cantilever boundary conditions,the flexural nonlinear differential equations of the rectangular sandwich plate are obtained via the Galerkin method.Since the natural vibration differential equations exhibit nonlinear characteristics,the multiscale method is employed to derive the expression for nonlinear natural frequency.An example analysis reveals how the natural frequency of a functionally graded sandwich rectangular plate varies with rotational speed and temperature.Results show that the nonlinear/linear frequency ratio increases with rotational angular velocity Ω and thickness-to-length ratio h/a,follows a cosine-like periodic pattern with the setting angle,and shows a sharp decrease followed by a rapid increase with increasing width-to-length ratio b/a.The derived analytical solutions for nonlinear frequency provide valuable insights for assessing the dynamic characteristics of functionally graded structures.
基金Supported by National Natural Science Foundation of China(Grant Nos.52275435,52075465,52375519)Open Fund Project of Jiangsu Key Laboratory of Precision and Micro-manufacturing Technology(Grant No.JSKL2324K03)Key Research and Development Program of Hunan Province of China(Grant No.2023GK2026)。
文摘Rotational feeding combined with shift feeding electrochemical trepanning(RF-SF ECTr)is an effective method for machining aeroengine blisks.However,given the variable relative motion of the electrodes and the complex flow channels around the bending and twisting blades,the accessibility and uniformity of the flow field are poor in blisk RF-SF ECTr using the traditional electrolyte supply(TES)mode,resulting in poor machining stability and low machining efficiency.To improve the distribution of the flow field,a new multi-channel electrolyte supply(MCES)mode is proposed for blisk RF-SF ECTr,in which the position and volume of the electrolyte supply are controlled effectively by setting multiple inlet channels in the liquid inlet area.A flow-field simulation comparison between TES and MCES shows that better accessibility and uniformity of the flow-field distribution are achieved under MCES.To clarify further the flow-field distribution characteristics under RF-SF ECTr,a series of flow-field simulations was conducted at different machining depths.Based on the obtained dynamic change law for the flow field,to enhance further its uniformity and accessibility,a global coverage strategy for the electrolyte supply and a flow-field structure optimization method for MCES are proposed,which involve optimizing the number,diameter,and location of the inlet channels.After many simulations,the optimal MCES structure was achieved whereby the electrolyte covers all positions effectively in the processing area.To verify the proposed method as effective and correct,a series of RF-SF ECTr experiments was carried out.Under the optimized MCES mode,the feeding rate was increased from 0.8 mm/min with the TES mode to 2.0 mm/min,and the processing stability and efficiency were improved significantly.The methods presented here offer an effective guide for flow-field optimization when machining other components with complex spatial structures.
基金supported by the National Natural Science Foundation of China,No.12261141689。
文摘Recent studies have increasingly identified extended main sequence turn-off(e MSTO)phenomena in Galactic open clusters,yet the number of such clusters with sufficient spectroscopic information for member stars remains limited.Unlike most studies that rely on fitting isochrones based on color–magnitude diagram(CMD)morphology to account for varying rotational velocities,our approach leverages LAMOST spectral data to compute actual rotational velocity distributions for confirmed cluster members,along with parameters such as metallicity,differential extinction,and rotational inclination,to utilize PARSEC isochrones for fitting the cluster CMDs.We systematically surveyed all known Galactic open clusters and selected 12 clusters where rotational velocity distributions could be reliably calculated for detailed fitting.Our results successfully reproduced the eMSTO phenomenon observed in these clusters.For the majority of clusters,considering only differential extinction and variations in rotational velocity adequately explains the position and morphology of the MSTO.For some intermediate-age clusters,incorporating rotational inclination additionally accounts for the broadening of the MSTO.This study underscores the importance of spectroscopic data in understanding eMSTO phenomena and provides a probable explanation for interpreting the combined effects of differential extinction,rotation,and inclination on the CMDs of Galactic open clusters.
