While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics ...While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation.This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge,with a focus on abrasive damage,grit protrusion height and uniformity,the number of effective abrasives,chip space,and bond morphology.The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments,using mechanical sharpening as the comparison group.The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods,albeit with minor graphitization and localized oxidative damage occurring.Furthermore,after being sharpened by the MW method,the grit protrusion height increased,demonstrating good uniformity,and simultaneously exhibiting a higher number of effective abrasives.Noticeable craters formed in proximity to the abrasives,augmenting chip space,but sputtering led to the formation of metal deposition layers on the abrasive surfaces.The MW-sharpened wheel exhibited superior grinding wear ratios,with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process pro-gressed.These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner,resulting in improved grinding surface quality.The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW,with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.展开更多
Traditional digitizers for signal readout of PET detectors are based on commercial analog-to-digital converters(ADC).However,the cost and power consumption of an entire electronic readout system based on digitizers fo...Traditional digitizers for signal readout of PET detectors are based on commercial analog-to-digital converters(ADC).However,the cost and power consumption of an entire electronic readout system based on digitizers for a PET scanner are high.To address this problem,a soft-core ADC based on a field-programmable gate array(FPGA)was proposed.An FPGA-based ADC(FPGA-ADC)combines low loss and high performance.To achieve good performance,the FPGA-ADC requires three calibrations:time-to-digital converter(TDC)length calibration,TDC alignment calibration,and TDC-to-ADC calibration.A prototype front-end electronics based on FPGA-ADC was built to evaluate the performance of time-of-flight positron emission tomography(TOF PET)detectors.Each PET detector consists of a LYSO crystal single-ended coupled to a silicon photomultiplier(SiPM).The experimental results show that the full-width at half-maximum(FWHM)energy resolution for 511 keV gamma photons after saturation correction of the SiPM was 12.3%.The FWHM coincidence timing resolution(CTR)of the TOF PET detector with the readout of the front-end electronic prototype is 385.2 ps.FPGA-ADCbased front-end electronics are very promising for multichannel,low-cost,highly integrated,and power-efficient readout electronic systems for radiation detector applications.展开更多
Objective To develop a dual-branch deep learning framework for accurate multi-label classification of fundus diseases,addressing the key limitations of insufficient complementary feature extraction and inadequate cros...Objective To develop a dual-branch deep learning framework for accurate multi-label classification of fundus diseases,addressing the key limitations of insufficient complementary feature extraction and inadequate cross-modal feature fusion in existing automated diagnostic methods.Methods The fundus multi-label classification dataset with 12 disease categories(FMLC-12)dataset was constructed by integrating complementary samples from Ocular Disease Intelligent Recognition(ODIR)and Retinal Fundus Multi-Disease Image Dataset(RFMiD),yielding 6936 fundus images across 12 retinal pathology categories,and the framework was validated on both FMLC-12 and ODIR.Inspired by the holistic multi-regional assessment principle of the Five Wheels theory in traditional Chinese medicine(TCM)ophthalmology,the dualbranch multi-label network(DBMNet)was developed as a novel framework integrating complementary visual feature extraction with pathological correlation modeling.The architecture employed a TransNeXt backbone within a dual-branch design:one branch processed redgreen-blue(RGB)images to capture color-dependent features,such as vascular patterns and lesion morphology,while the other processed grayscale-converted images to enhance subtle textural details and contrast variations.A feature interaction module(FIM)effectively integrated the multi-scale features from both branches.Comprehensive ablation studies were conducted to evaluate the contributions of the dual-branch architecture and the FIM.The performance of DBMNet was compared against four state-of-the-art methods,including EfficientNet Ensemble,transfer learning-based convolutional neural network(CNN),BFENet,and EyeDeep-Net,using mean average precision(mAP),F1-score,and Cohen's kappa coefficient.Results The dual-branch architecture improved mAP by 15.44 percentage points over the single-branch TransNeXt baseline,increasing from 34.41%to 44.24%,and the addition of FIM further boosted mAP to 49.85%.On FMLC-12,DBMNet achieved an mAP of 49.85%,a Cohen’s kappa coefficient of 62.14%,and an F1-score of 70.21%.Compared with BFENet(mAP:45.42%,kappa:46.64%,F1-score:71.34%),DBMNet outperformed it by 4.43 percentage points in mAP and 15.50 percentage points in kappa,while BFENet achieved a marginally higher F1-score.On ODIR,DBMNet achieved an F1-score of 85.50%,comparable to state-of-the-art methods.Conclusion DBMNet effectively integrates RGB and grayscale visual modalities through a dual-branch architecture,significantly improving multi-label fundus disease classification.The framework not only addresses the issue of insufficient feature fusion in existing methods but also demonstrates outstanding performance in balancing detection across both common and rare diseases,providing a promising and clinically applicable pathway for standardized,intelligent fundus disease classification.展开更多
With the continuous development of the offshore wind industry,the design concept of composite foundation has been given attention in the past decade.This paper presents an accurate method for investigating the horizon...With the continuous development of the offshore wind industry,the design concept of composite foundation has been given attention in the past decade.This paper presents an accurate method for investigating the horizontal vibration of monopile-friction wheel composite foundations in layered saturated soil.Firstly,the three-dimensional continuum mechanics theory with the range of linear elasticity is introduced to calculate the frictional resistance distributed on the upper soil surface.Then,the resistances of multilayered soils and inviscid seawater to the pile shaft under horizontal harmonic excitation are obtained using Novak's plane strain model,Biot's porous media theory and radiationwave theory.Thirdly,the expressions for the deformation,bending moment and internal force of the Euler-Bernoulli pile are derived using the boundary conditions with definitephysical meaning and transfer matrix method.By comparing with the results of 1g laboratory test and the idealized formula reported by the literature,the rationality and accuracy of the developed dynamical model can be verified.Finally,this paper conducts a series of worked examples to investigate the influencesof the elastic modulus and thickness of three-layer saturated soil and the location of interlayer soil on the horizontal dynamic vibration of composite foundation.The results show that an increase in elastic modulus of the surface soil is an effective way to improve the dynamic stability of the composite foundation in service conditions.The conclusions drawn from the numerical examples can develop some guidelines for the current foundation design of offshore wind turbines.展开更多
Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery ...Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.展开更多
Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed railways.They can cause significant wheel-rail dynamic interactions,leading to wheel-rail ...Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed railways.They can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and deterioration.Few researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry irregularities.However,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric shape.In this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to Shanghai.The vertical dynamic forces in the time and frequency domains were compared under different running speeds.These forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed model.Finally,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is found.The results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the literature.The ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.展开更多
Traditionally,a continuous-wave(CW)signal is used to simulate RF circuits during the design procedure,while the fabricated circuits are measured by modulated signals in the test phase,because modulated signals are use...Traditionally,a continuous-wave(CW)signal is used to simulate RF circuits during the design procedure,while the fabricated circuits are measured by modulated signals in the test phase,because modulated signals are used in reality.It is almost impossible to use a CW signal to predict system performances,such as error vector magnitude(EVM),bit error rate(BER),etc.,of a transceiver front-end when dealing with complex modulated signals.This paper develops an integrated system evaluation engine(ISEE)to evaluate the system performances of a transceiver front-end or its sub-circuits.This crossdomain simulation platform is based on Matlab,advanced design system(ADS),and Cadence simulators to link the baseband signals and transceiver frond-end.An orthogonal frequency division multiplex(OFDM)modem is implemented in Matlab for evaluating the system performances.The modulated baseband signal from Matlab is dynamically fed into ADS,which includes transceiver front-end for co-simulation.The sub-block circuits of the transceiver front-end can be implemented using ADS and Cadence simulators.After system-level circuit simulation in ADS,the output signal is dynamically delivered to Matlab for demodulation.To simplify the use of the co-simulation platform,a graphical user interface(GUI)is constructed using Matlab.The parameters of the OFDM signals can be easily reconfigured on the GUI to simulate RF circuits with different modulation schemes.To demonstrate the effectiveness of the ISEE,a 3.5 GHz power amplifier is simulated and characterized using 20 MHz 16-and 64-QAM OFDM signals.展开更多
Nowadays,using mobile robots in different applications has been very important.However,the environment in which they operate can cause the wheels to slip or the robot body to slide,causing the assigned task not to be ...Nowadays,using mobile robots in different applications has been very important.However,the environment in which they operate can cause the wheels to slip or the robot body to slide,causing the assigned task not to be performed successfully.Therefore,the need arises to mathematically determine these external perturbations to predict the behavior of the mobile robot.Based on the above mentioned facts,this work focuses on obtaining the kinematic model of an omnidirectional mobile robot considering lateral and longitudinal sliding disturbances of the body and wheel slippage.To mitigate the effect of the disturbances,a control strategy is considered based on the design of a generalized proportional integral observer(GPIO)that allows the estimation of such perturbations.Then,an active disturbance rejection control(ADRC)methodology is implemented to solve the trajectory tracking problem,and it is theoretically proved that the tracking errors converge to a vicinity near the origin.Numerical simulations and real-time experiments validate the obtained perturbed model and the control strategy performance,achieving the desired trajectory tracking despite these perturbations.展开更多
In response to the pain points of rapid iteration of front-end education technology,large differences in learner foundations,and a lack of practical scenarios,this paper combines generative artificial intelligence and...In response to the pain points of rapid iteration of front-end education technology,large differences in learner foundations,and a lack of practical scenarios,this paper combines generative artificial intelligence and AI agents to analyze the empowerment logic from three dimensions:knowledge ecology reconstruction,cognitive collaborative upgrading,and teaching methodology innovation.It explores its application scenarios in teaching and learning,sorts out challenges such as technology adaptation and learning dependence,and proposes paths such as building an exclusive AI ecosystem and optimizing the guidance mechanism of intelligent agents to provide support for the digital transformation of front-end education.展开更多
Non-pneumatic wheels inherently offer explosion-proof advantages compared to pneumatic wheel.Our team innovatively proposed an“elastic ring-hinge group”type non-pneumatic mechanical elastic wheel(ME-Wheel).To analyz...Non-pneumatic wheels inherently offer explosion-proof advantages compared to pneumatic wheel.Our team innovatively proposed an“elastic ring-hinge group”type non-pneumatic mechanical elastic wheel(ME-Wheel).To analyze the gas flow characteristics around the ME-Wheel,this study analyzed the aerodynamic characteristics of the MEWheel for the first time by using CFD calculation method,and studied the influences of speed,steering angle,camber angle and hinge group on the aerodynamic characteristics of the wheel.Compared with camber angle,steering angle has a more significant effect on the aerodynamic characteristics of non-pneumatic mechanical elastic wheels in terms of lift and drag.Speed has no significant effect on the wheel drag coefficient and lift coefficient.The number of hinge groups has a significant effect on wheel aerodynamic characteristics.The deviations between the maximum and minimum values of drag,lift,drag coefficient,and lift coefficient are 6.06%,8.57%,6.05%,and 8.6%,respectively.This study addresses a critical gap in the design optimization of ME-Wheel,provides a theoretical basis for the aerodynamic optimization of ME-Wheel,and has strong practical significance for the commercial development of nonpneumatic mechanical elastic wheels.展开更多
The wheeled bipedal robots have great application potential in environments with a mixture of structured and unstructured terrain. However, wheeled bipedal robots have problems such as poor balance ability and low mov...The wheeled bipedal robots have great application potential in environments with a mixture of structured and unstructured terrain. However, wheeled bipedal robots have problems such as poor balance ability and low movement level on rough roads. In this paper, a novel and low-cost wheeled bipedal robot with an asymmetrical five-link mechanism is proposed, and the kinematics of the legs and the dynamics of the Wheeled Inverted Pendulum (WIP) are modeled. The primary balance controller of the wheeled bipedal robot is built based on the Linear Quadratic Regulator (LQR) and the compensation method of the virtual pitch angle adjusting the Center of Mass (CoM) position, then the whole-body hybrid torque-position control is established by combining attitude and leg controllers. The stability of the robot’s attitude control and motion is verified with simulations and prototype experiments, which confirm the robot’s ability to pass through complex terrain and resist external interference. The feasibility and reliability of the proposed control model are verified.展开更多
The problem of trajectory tracking for a class of differentially driven wheeled mobile robots(WMRs)under partial loss of the effectiveness of the actuated wheels is investigated in this paper.Such actuator faults may ...The problem of trajectory tracking for a class of differentially driven wheeled mobile robots(WMRs)under partial loss of the effectiveness of the actuated wheels is investigated in this paper.Such actuator faults may cause the loss of strong controllability of the WMR,such that the conventional fault-tolerant control strategies unworkable.In this paper,a new mixed-gain adaption scheme is devised,which is adopted to adapt the gain of a decoupling prescribed performance controller to adaptively compensate for the loss of the effectiveness of the actuators.Different from the existing gain adaption technique which depends on both the barrier functions and their partial derivatives,ours involves only the barrier functions.This yields a lower magnitude of the resulting control signals.Our controller accomplishes trajectory tracking of the WMR with the prescribed rate and accuracy even in the faulty case,and the control design relies on neither the information of the WMR dynamics and the actuator faults nor the tools for function approximation,parameter identification,and fault detection or estimation.The comparative simulation results justify the theoretical findings.展开更多
Conventional deformable wheel systems in robots and other mechatronic systems face significant challenges in achieving miniaturization,intelligence,and integration.To address these issues,we propose a novel integrated...Conventional deformable wheel systems in robots and other mechatronic systems face significant challenges in achieving miniaturization,intelligence,and integration.To address these issues,we propose a novel integrated structural design method and four-dimensional printing strategy for deformable wheels capable of shaping among multiple programmable direct-driven deformation configurations.The load-bearing capacity of the printed wheel is strengthened by employing deformed components in various locations and actuated states.Additionally,a novel analytical design method is presented to determine the structure,actuation,and deformation parameters of each component under complex coupled deformation.Our findings reveal that the designed wheel can transform into three different configurations,exhibiting desired deformations of 12.5%in the radial direction and 19.6%in the axial direction.It also demonstrates robust deformation behavior and structural stability under multi-directional loads.By integrating a terrain sensing system,the designed wheel exhibits highly adaptive deformation capabilities on various terrains,showing great potential for exploring complex environments.展开更多
To reduce structural modifications and minimize the impact on legged locomotion,this paper presents SlidBot,a quadruped robot with roller-skating capability,designed to improve movement efficiency on sloped surfaces.T...To reduce structural modifications and minimize the impact on legged locomotion,this paper presents SlidBot,a quadruped robot with roller-skating capability,designed to improve movement efficiency on sloped surfaces.Two passive wheels without braking mechanisms are installed on the knee joint and lower leg of the robot.During quadruped movement,these wheels remain off the ground and therefore do not interfere with locomotion.The brakeless design reduces the number of components and simplifies the mechanical structure.When roller skating motion is required,simply adjust the leg posture to make the passive wheel on the lower leg contact the ground.The roller skating mode of the robot can be divided into two-legged roller skating and four-legged roller skating.During two-legged roller skating,the passive wheels of the hind legs support the ground,and the front legs execute backward propulsion to provide power for the robot’s movement.In four-legged roller skating,both the front and hind legs’passive wheels contact the ground,resulting in a large supporting area and a low center of gravity,which helps maintain stability during high-speed movement and facilitates passage through low-lying environments.This paper outlines the robot design method,establishes a kinematic model,plans the gait and mode-switching method.Simulation and physical results indicate that the robot can perform stable diagonal trotting and roller skating movements.Moreover,on flat terrain,the roller skating motion is more energy-efficient than diagonal trotting,and on slopes,its energy and motion efficiency significantly surpasses that of the diagonal trot.This research offers novel insights for quadruped robot design and can considerably enhance the movement efficiency of quadruped robots on sloped terrains.展开更多
Objective:To analyze the application effect of the Behavior Change Wheel(BCW)theory in fall prevention management for elderly inpatients.Methods:One hundred elderly inpatients admitted to Kunshan Fourth People’s Hosp...Objective:To analyze the application effect of the Behavior Change Wheel(BCW)theory in fall prevention management for elderly inpatients.Methods:One hundred elderly inpatients admitted to Kunshan Fourth People’s Hospital from January 2019 to April 2024 were selected and divided into an experimental group(fall prevention management intervention based on BCW theory)and a control group(routine fall prevention management intervention)using random sampling,with 50 patients in each group.The differences in knowledge,attitude,and behavior levels of fall prevention,prevention efficacy,and the incidence of falls and fall-related injuries during hospitalization,6 months after discharge,and 1 year after discharge were compared between the two groups.Results:Compared with before the intervention,the scores of the fall prevention knowledge,attitude,and behavior scale(knowledge dimension,attitude dimension,behavior dimension,and total score)for elderly inpatients in both groups increased,and the improvement in the experimental group was greater than that in the control group(P<0.05).After the intervention,the revised fall efficacy scale score was higher in the experimental group compared to the control group(P<0.05).The incidence of falls during hospitalization,6 months after discharge,and 1 year after discharge,as well as the rate of fall-related injuries 6 months and 1 year after discharge,were lower in the experimental group than in the control group(P<0.05).There was no statistically significant difference in the rate of fall-related injuries during hospitalization between the two groups(P>0.05).Conclusion:The fall prevention management intervention based on BCW theory has good application value in elderly inpatients.It effectively improves patients’knowledge,attitudes,and behavior levels regarding fall prevention,significantly enhances their self-prevention efficacy,and demonstrates good results in reducing the incidence of falls during hospitalization and after discharge.展开更多
The momentum wheel assumes a dominant role as an inertial actuator for satellite attitude control systems.Due to the effects of structural aging and external interference,the momentum wheel may experience the gradual ...The momentum wheel assumes a dominant role as an inertial actuator for satellite attitude control systems.Due to the effects of structural aging and external interference,the momentum wheel may experience the gradual emergence of irreversible faults.These fault features will become apparent in the telemetry signal transmitted by the momentum wheel.This paper introduces ADTWformer,a lightweight model for long-term prediction of time series,to analyze the time evolution trend and multi-dimensional data coupling mechanism of satellite momentum wheel faults.Moreover,the incorporation of the approximate Markov blanket with the maximum information coefficient presents a novel methodology for performing correlation analysis,providing significant perspectives from a data-centric standpoint.Ultimately,the creation of an adaptive alarm mechanism allows for the successful attainment of the momentum wheel fault warning by detecting the changes in the health status curves.The analysis methodology outlined in this article has exhibited positive results in identifying instances of satellite momentum wheel failure in two scenarios,thereby showcasing considerable promise for large-scale applications.展开更多
The dynamic recrystallization(DRX)behavior and texture formation mechanism in an AZ31 magnesium alloy wheel hub during the spinning process were investigated.Analysis using optical microscopy,electron backscatter diff...The dynamic recrystallization(DRX)behavior and texture formation mechanism in an AZ31 magnesium alloy wheel hub during the spinning process were investigated.Analysis using optical microscopy,electron backscatter diffraction,transmission electron microscopy,and finite element simulation revealed that continuous dynamic recrystallization(CDRX)and grain boundary bulging occurred simultaneously throughout the spinning process,leading to an increased proportion of DRXed grain areas.The newly formed DRXed grains largely retained the orientations of their deformed parent grains.The spinning process had two stages:initially,deformation was driven by basalslip as the roller contacted the alloy and descended to its lowest point.In the later stage,pyramidal<c+a>slips became predominant as additional force was applied along the spinning direction(SD),forming a final texture with the c-axis tilting±15°towards the SD.This texture development led to discernible anisotropy in tensile properties along the SD and the tangential direction(TD).展开更多
Because the grinding temperature is high when grinding using conventional disordered grinding wheels,the grinding quality improvement is limited when using single abrasive ordered grinding wheels,and the wheel prepara...Because the grinding temperature is high when grinding using conventional disordered grinding wheels,the grinding quality improvement is limited when using single abrasive ordered grinding wheels,and the wheel preparation process is complex and costly when using microstructured grinding wheels,abrasive groups ordered grinding wheels are widely investigated.However,there is a paucity of systematic analyses and comprehensive reviews focused on abrasive groups ordered grinding wheels.Therefore,this paper defines abrasive groups ordered grinding wheels and classifies them,based on their unique characteristics,into groups such as abrasive blocks ordered grinding wheel,fine grain structured grinding wheel,abrasive clusters ordered grinding wheel,and abrasive fibers ordered grinding wheel.We provide an overview of the latest advances in wheel structures,preparation methods,and abrasive selection for various types of abrasive groups ordered grinding wheels.Furthermore,we conduct a comparative analysis of the existing types,significant advantages,and challenges associated with the four types of abrasive groups ordered grinding wheels.Looking ahead,given the potential of abrasive groups ordered grinding wheels in reducing grinding force and temperature,we recommend further exploration of their application in combination with special processing techniques.This could pave the way for the development of machining processes that are more environmentally friendly,energy-efficient,and precise.展开更多
In recent years,the development of solid-state lighting devices has increasingly shifted towards high-power laser illumination,making it imperative to develop fluorescent conversion materials with exceptional thermal ...In recent years,the development of solid-state lighting devices has increasingly shifted towards high-power laser illumination,making it imperative to develop fluorescent conversion materials with exceptional thermal stability and luminous quality.In this study,we introduced a highly reflective TiO_(2) substrate in combination with a high thermal conductivity AlN substrate to design a Ce:YAG-PiG-TiO_(2)-AlN Film(Ce:YAG PTAF)color converter with outstanding photothermal performance.Remarkably,the thermal conductivity of this material reaches 48.28 W m^(-1) K^(-1).Notably,the optimized PTAF can withstand a high-power output of up to 12.14 W in a static environment,with a maximum luminous flux(LFmax)of 2284.6 lm and maximum luminous efficacy(LEmax)of 222.35 lm W^(-1),showcasing its excellent optical properties.Furthermore,the fabricated Ce:YAG-PiG-TiO_(2)-AlN-Wheel(Ce:YAG PTAW),equipped with a motor operating at 7200 r/min,emits an extraordinary brightness of 4404 lm under 88 W of ultra-high laser irradiation,with stability surpassing that of commercial silicone color wheels,thanks to its superior Li_(2)O-Al_(2)O_(3)-SiO_(2)(LAS)glass system.Interestingly,we designed an innovative spatially separated two-color segmented wheel structure,effectively mitigating the photon reabsorption phenomenon caused by the overlap of the fluorescent powder absorption peaks.When the ratio of Ce:YAG to Ce:GdYAG is 240:120,it yields white light with a color rendering index(CRI)of 80.2,and luminous flux remaining at 3317.8 lm.When encapsulated in a reflective module,it accurately reflects the true color states of objects.These results collectively indicate that both Ce:YAG PTAF and PTAW possess significant application potential in the realm of high-power laser illumination.展开更多
基金Supported by Hunan Provincial Natural Science Foundation(Grant Nos.2023JJ60182 and 2025JJ50273)Scientific Research Fund of Hunan Provincial Education Department(Grant Nos.22B0561 and 23C0188)National Natural Science Foundation of China(Grant No.52305465).
文摘While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation.This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge,with a focus on abrasive damage,grit protrusion height and uniformity,the number of effective abrasives,chip space,and bond morphology.The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments,using mechanical sharpening as the comparison group.The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods,albeit with minor graphitization and localized oxidative damage occurring.Furthermore,after being sharpened by the MW method,the grit protrusion height increased,demonstrating good uniformity,and simultaneously exhibiting a higher number of effective abrasives.Noticeable craters formed in proximity to the abrasives,augmenting chip space,but sputtering led to the formation of metal deposition layers on the abrasive surfaces.The MW-sharpened wheel exhibited superior grinding wear ratios,with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process pro-gressed.These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner,resulting in improved grinding surface quality.The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW,with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.
基金supported by the Key R&D Program of Shandong Province(No.2023SFGC0101)Shandong Excellent Young Scientists Fund Program(Overseas)(No.2023HWYQ-047)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2022QA039)the National Natural Science Foundation of China(NSFC)(No.U2106202).
文摘Traditional digitizers for signal readout of PET detectors are based on commercial analog-to-digital converters(ADC).However,the cost and power consumption of an entire electronic readout system based on digitizers for a PET scanner are high.To address this problem,a soft-core ADC based on a field-programmable gate array(FPGA)was proposed.An FPGA-based ADC(FPGA-ADC)combines low loss and high performance.To achieve good performance,the FPGA-ADC requires three calibrations:time-to-digital converter(TDC)length calibration,TDC alignment calibration,and TDC-to-ADC calibration.A prototype front-end electronics based on FPGA-ADC was built to evaluate the performance of time-of-flight positron emission tomography(TOF PET)detectors.Each PET detector consists of a LYSO crystal single-ended coupled to a silicon photomultiplier(SiPM).The experimental results show that the full-width at half-maximum(FWHM)energy resolution for 511 keV gamma photons after saturation correction of the SiPM was 12.3%.The FWHM coincidence timing resolution(CTR)of the TOF PET detector with the readout of the front-end electronic prototype is 385.2 ps.FPGA-ADCbased front-end electronics are very promising for multichannel,low-cost,highly integrated,and power-efficient readout electronic systems for radiation detector applications.
基金Natural Science Foundation of Hunan Province(2025JJ90031)Key Research and Development Program of Hunan Province of China(23A0273)Hunan Provincial Administration of Traditional Chinese Medicine(A2023048).
文摘Objective To develop a dual-branch deep learning framework for accurate multi-label classification of fundus diseases,addressing the key limitations of insufficient complementary feature extraction and inadequate cross-modal feature fusion in existing automated diagnostic methods.Methods The fundus multi-label classification dataset with 12 disease categories(FMLC-12)dataset was constructed by integrating complementary samples from Ocular Disease Intelligent Recognition(ODIR)and Retinal Fundus Multi-Disease Image Dataset(RFMiD),yielding 6936 fundus images across 12 retinal pathology categories,and the framework was validated on both FMLC-12 and ODIR.Inspired by the holistic multi-regional assessment principle of the Five Wheels theory in traditional Chinese medicine(TCM)ophthalmology,the dualbranch multi-label network(DBMNet)was developed as a novel framework integrating complementary visual feature extraction with pathological correlation modeling.The architecture employed a TransNeXt backbone within a dual-branch design:one branch processed redgreen-blue(RGB)images to capture color-dependent features,such as vascular patterns and lesion morphology,while the other processed grayscale-converted images to enhance subtle textural details and contrast variations.A feature interaction module(FIM)effectively integrated the multi-scale features from both branches.Comprehensive ablation studies were conducted to evaluate the contributions of the dual-branch architecture and the FIM.The performance of DBMNet was compared against four state-of-the-art methods,including EfficientNet Ensemble,transfer learning-based convolutional neural network(CNN),BFENet,and EyeDeep-Net,using mean average precision(mAP),F1-score,and Cohen's kappa coefficient.Results The dual-branch architecture improved mAP by 15.44 percentage points over the single-branch TransNeXt baseline,increasing from 34.41%to 44.24%,and the addition of FIM further boosted mAP to 49.85%.On FMLC-12,DBMNet achieved an mAP of 49.85%,a Cohen’s kappa coefficient of 62.14%,and an F1-score of 70.21%.Compared with BFENet(mAP:45.42%,kappa:46.64%,F1-score:71.34%),DBMNet outperformed it by 4.43 percentage points in mAP and 15.50 percentage points in kappa,while BFENet achieved a marginally higher F1-score.On ODIR,DBMNet achieved an F1-score of 85.50%,comparable to state-of-the-art methods.Conclusion DBMNet effectively integrates RGB and grayscale visual modalities through a dual-branch architecture,significantly improving multi-label fundus disease classification.The framework not only addresses the issue of insufficient feature fusion in existing methods but also demonstrates outstanding performance in balancing detection across both common and rare diseases,providing a promising and clinically applicable pathway for standardized,intelligent fundus disease classification.
基金supported by the National Natural Science Foundation of China(Grant No.52178329),the China Scholarship Council(Grant No.202306130155)the Postgraduate Scientific Research Innovation Project of Hunan Province,China(Grant No.CX20230442).
文摘With the continuous development of the offshore wind industry,the design concept of composite foundation has been given attention in the past decade.This paper presents an accurate method for investigating the horizontal vibration of monopile-friction wheel composite foundations in layered saturated soil.Firstly,the three-dimensional continuum mechanics theory with the range of linear elasticity is introduced to calculate the frictional resistance distributed on the upper soil surface.Then,the resistances of multilayered soils and inviscid seawater to the pile shaft under horizontal harmonic excitation are obtained using Novak's plane strain model,Biot's porous media theory and radiationwave theory.Thirdly,the expressions for the deformation,bending moment and internal force of the Euler-Bernoulli pile are derived using the boundary conditions with definitephysical meaning and transfer matrix method.By comparing with the results of 1g laboratory test and the idealized formula reported by the literature,the rationality and accuracy of the developed dynamical model can be verified.Finally,this paper conducts a series of worked examples to investigate the influencesof the elastic modulus and thickness of three-layer saturated soil and the location of interlayer soil on the horizontal dynamic vibration of composite foundation.The results show that an increase in elastic modulus of the surface soil is an effective way to improve the dynamic stability of the composite foundation in service conditions.The conclusions drawn from the numerical examples can develop some guidelines for the current foundation design of offshore wind turbines.
基金supported by the NIH (R01NS103481, R01NS111776, and R01NS131489)Indiana Department of Health (ISDH58180)(all to WW)。
文摘Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.
基金supported by Natural Science Foundation of China(52178441)the Scientific Research Projects of the China Academy of Railway Sciences Co.,Ltd.(Grant No.2022YJ043).
文摘Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed railways.They can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and deterioration.Few researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry irregularities.However,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric shape.In this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to Shanghai.The vertical dynamic forces in the time and frequency domains were compared under different running speeds.These forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed model.Finally,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is found.The results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the literature.The ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.
基金supported by the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone(No.HZQB-KCZYB-2020083).
文摘Traditionally,a continuous-wave(CW)signal is used to simulate RF circuits during the design procedure,while the fabricated circuits are measured by modulated signals in the test phase,because modulated signals are used in reality.It is almost impossible to use a CW signal to predict system performances,such as error vector magnitude(EVM),bit error rate(BER),etc.,of a transceiver front-end when dealing with complex modulated signals.This paper develops an integrated system evaluation engine(ISEE)to evaluate the system performances of a transceiver front-end or its sub-circuits.This crossdomain simulation platform is based on Matlab,advanced design system(ADS),and Cadence simulators to link the baseband signals and transceiver frond-end.An orthogonal frequency division multiplex(OFDM)modem is implemented in Matlab for evaluating the system performances.The modulated baseband signal from Matlab is dynamically fed into ADS,which includes transceiver front-end for co-simulation.The sub-block circuits of the transceiver front-end can be implemented using ADS and Cadence simulators.After system-level circuit simulation in ADS,the output signal is dynamically delivered to Matlab for demodulation.To simplify the use of the co-simulation platform,a graphical user interface(GUI)is constructed using Matlab.The parameters of the OFDM signals can be easily reconfigured on the GUI to simulate RF circuits with different modulation schemes.To demonstrate the effectiveness of the ISEE,a 3.5 GHz power amplifier is simulated and characterized using 20 MHz 16-and 64-QAM OFDM signals.
基金supported by Instituto Politécnico Nacional-Secretaría de Investigación y Posgrado under grant 20253806in part by project UNAM PAPIME PE104125.
文摘Nowadays,using mobile robots in different applications has been very important.However,the environment in which they operate can cause the wheels to slip or the robot body to slide,causing the assigned task not to be performed successfully.Therefore,the need arises to mathematically determine these external perturbations to predict the behavior of the mobile robot.Based on the above mentioned facts,this work focuses on obtaining the kinematic model of an omnidirectional mobile robot considering lateral and longitudinal sliding disturbances of the body and wheel slippage.To mitigate the effect of the disturbances,a control strategy is considered based on the design of a generalized proportional integral observer(GPIO)that allows the estimation of such perturbations.Then,an active disturbance rejection control(ADRC)methodology is implemented to solve the trajectory tracking problem,and it is theoretically proved that the tracking errors converge to a vicinity near the origin.Numerical simulations and real-time experiments validate the obtained perturbed model and the control strategy performance,achieving the desired trajectory tracking despite these perturbations.
基金funded by two 2024 Ministry of Education supply-demand docking employment and education projects(Grant No.2024101679202,Grant No.2024121116066)2024“Innovation Strong Institute Project of Guangdong Polytechnic Institute”(Grant No.2024CQ-29)2022 Guangdong Province Undergraduate Online Open Course Guidance Committee Research Project(Grant No.2022ZXKC612).
文摘In response to the pain points of rapid iteration of front-end education technology,large differences in learner foundations,and a lack of practical scenarios,this paper combines generative artificial intelligence and AI agents to analyze the empowerment logic from three dimensions:knowledge ecology reconstruction,cognitive collaborative upgrading,and teaching methodology innovation.It explores its application scenarios in teaching and learning,sorts out challenges such as technology adaptation and learning dependence,and proposes paths such as building an exclusive AI ecosystem and optimizing the guidance mechanism of intelligent agents to provide support for the digital transformation of front-end education.
基金Supported by National Natural Science Foundation of China(Grant Nos.52472411,52272397)the Key Research&Development and Achievement Transformation Program of Wuhu(Grant No.2023YF010)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX25_0566).
文摘Non-pneumatic wheels inherently offer explosion-proof advantages compared to pneumatic wheel.Our team innovatively proposed an“elastic ring-hinge group”type non-pneumatic mechanical elastic wheel(ME-Wheel).To analyze the gas flow characteristics around the ME-Wheel,this study analyzed the aerodynamic characteristics of the MEWheel for the first time by using CFD calculation method,and studied the influences of speed,steering angle,camber angle and hinge group on the aerodynamic characteristics of the wheel.Compared with camber angle,steering angle has a more significant effect on the aerodynamic characteristics of non-pneumatic mechanical elastic wheels in terms of lift and drag.Speed has no significant effect on the wheel drag coefficient and lift coefficient.The number of hinge groups has a significant effect on wheel aerodynamic characteristics.The deviations between the maximum and minimum values of drag,lift,drag coefficient,and lift coefficient are 6.06%,8.57%,6.05%,and 8.6%,respectively.This study addresses a critical gap in the design optimization of ME-Wheel,provides a theoretical basis for the aerodynamic optimization of ME-Wheel,and has strong practical significance for the commercial development of nonpneumatic mechanical elastic wheels.
基金supported in part by the National Natural Science Foundationof China under Grant(61801122)Natural Science Foundation of FujianProvince(2022J01542).
文摘The wheeled bipedal robots have great application potential in environments with a mixture of structured and unstructured terrain. However, wheeled bipedal robots have problems such as poor balance ability and low movement level on rough roads. In this paper, a novel and low-cost wheeled bipedal robot with an asymmetrical five-link mechanism is proposed, and the kinematics of the legs and the dynamics of the Wheeled Inverted Pendulum (WIP) are modeled. The primary balance controller of the wheeled bipedal robot is built based on the Linear Quadratic Regulator (LQR) and the compensation method of the virtual pitch angle adjusting the Center of Mass (CoM) position, then the whole-body hybrid torque-position control is established by combining attitude and leg controllers. The stability of the robot’s attitude control and motion is verified with simulations and prototype experiments, which confirm the robot’s ability to pass through complex terrain and resist external interference. The feasibility and reliability of the proposed control model are verified.
基金supported in part by the National Natural Science Foundation of China under Grants 61991404,62103093 and 62473089the Research Program of the Liaoning Liaohe Laboratory,China under Grant LLL23ZZ-05-01+5 种基金the Key Research and Development Program of Liaoning Province of China under Grant 2023JH26/10200011the 111 Project 2.0 of China under Grant B08015,the National Key Research and Development Program of China under Grant 2022YFB3305905the Xingliao Talent Program of Liaoning Province of China under Grant XLYC2203130the Natural Science Foundation of Liaoning Province of China under Grants 2024JH3/10200012 and 2023-MS-087the Open Research Project of the State Key Laboratory of Industrial Control Technology of China under Grant ICT2024B12the Fundamental Research Funds for the Central Universities of China under Grants N2108003 and N2424004.
文摘The problem of trajectory tracking for a class of differentially driven wheeled mobile robots(WMRs)under partial loss of the effectiveness of the actuated wheels is investigated in this paper.Such actuator faults may cause the loss of strong controllability of the WMR,such that the conventional fault-tolerant control strategies unworkable.In this paper,a new mixed-gain adaption scheme is devised,which is adopted to adapt the gain of a decoupling prescribed performance controller to adaptively compensate for the loss of the effectiveness of the actuators.Different from the existing gain adaption technique which depends on both the barrier functions and their partial derivatives,ours involves only the barrier functions.This yields a lower magnitude of the resulting control signals.Our controller accomplishes trajectory tracking of the WMR with the prescribed rate and accuracy even in the faulty case,and the control design relies on neither the information of the WMR dynamics and the actuator faults nor the tools for function approximation,parameter identification,and fault detection or estimation.The comparative simulation results justify the theoretical findings.
基金supported by the National Key Research and Development Program of China(Grant No 2022YFB4600102)the National Natural Science Foundation of China(Grant No.U23A20637 and Grant No 52275561)。
文摘Conventional deformable wheel systems in robots and other mechatronic systems face significant challenges in achieving miniaturization,intelligence,and integration.To address these issues,we propose a novel integrated structural design method and four-dimensional printing strategy for deformable wheels capable of shaping among multiple programmable direct-driven deformation configurations.The load-bearing capacity of the printed wheel is strengthened by employing deformed components in various locations and actuated states.Additionally,a novel analytical design method is presented to determine the structure,actuation,and deformation parameters of each component under complex coupled deformation.Our findings reveal that the designed wheel can transform into three different configurations,exhibiting desired deformations of 12.5%in the radial direction and 19.6%in the axial direction.It also demonstrates robust deformation behavior and structural stability under multi-directional loads.By integrating a terrain sensing system,the designed wheel exhibits highly adaptive deformation capabilities on various terrains,showing great potential for exploring complex environments.
基金supported by the National Natural Science Foundation of China(Nos.62103197 and 62473200).
文摘To reduce structural modifications and minimize the impact on legged locomotion,this paper presents SlidBot,a quadruped robot with roller-skating capability,designed to improve movement efficiency on sloped surfaces.Two passive wheels without braking mechanisms are installed on the knee joint and lower leg of the robot.During quadruped movement,these wheels remain off the ground and therefore do not interfere with locomotion.The brakeless design reduces the number of components and simplifies the mechanical structure.When roller skating motion is required,simply adjust the leg posture to make the passive wheel on the lower leg contact the ground.The roller skating mode of the robot can be divided into two-legged roller skating and four-legged roller skating.During two-legged roller skating,the passive wheels of the hind legs support the ground,and the front legs execute backward propulsion to provide power for the robot’s movement.In four-legged roller skating,both the front and hind legs’passive wheels contact the ground,resulting in a large supporting area and a low center of gravity,which helps maintain stability during high-speed movement and facilitates passage through low-lying environments.This paper outlines the robot design method,establishes a kinematic model,plans the gait and mode-switching method.Simulation and physical results indicate that the robot can perform stable diagonal trotting and roller skating movements.Moreover,on flat terrain,the roller skating motion is more energy-efficient than diagonal trotting,and on slopes,its energy and motion efficiency significantly surpasses that of the diagonal trot.This research offers novel insights for quadruped robot design and can considerably enhance the movement efficiency of quadruped robots on sloped terrains.
基金Application of Behavior Change Wheel(BCW)Theory in Fall Prevention Management for Elderly Hospitalized Patients(Key Research and Development Program of Kunshan City,Jiangsu Province(KS2372))。
文摘Objective:To analyze the application effect of the Behavior Change Wheel(BCW)theory in fall prevention management for elderly inpatients.Methods:One hundred elderly inpatients admitted to Kunshan Fourth People’s Hospital from January 2019 to April 2024 were selected and divided into an experimental group(fall prevention management intervention based on BCW theory)and a control group(routine fall prevention management intervention)using random sampling,with 50 patients in each group.The differences in knowledge,attitude,and behavior levels of fall prevention,prevention efficacy,and the incidence of falls and fall-related injuries during hospitalization,6 months after discharge,and 1 year after discharge were compared between the two groups.Results:Compared with before the intervention,the scores of the fall prevention knowledge,attitude,and behavior scale(knowledge dimension,attitude dimension,behavior dimension,and total score)for elderly inpatients in both groups increased,and the improvement in the experimental group was greater than that in the control group(P<0.05).After the intervention,the revised fall efficacy scale score was higher in the experimental group compared to the control group(P<0.05).The incidence of falls during hospitalization,6 months after discharge,and 1 year after discharge,as well as the rate of fall-related injuries 6 months and 1 year after discharge,were lower in the experimental group than in the control group(P<0.05).There was no statistically significant difference in the rate of fall-related injuries during hospitalization between the two groups(P>0.05).Conclusion:The fall prevention management intervention based on BCW theory has good application value in elderly inpatients.It effectively improves patients’knowledge,attitudes,and behavior levels regarding fall prevention,significantly enhances their self-prevention efficacy,and demonstrates good results in reducing the incidence of falls during hospitalization and after discharge.
基金supported by the Science Center Program of National Natural Science Foundation of China(62188101)the National Natural Science Foundation of China(61833009,61690212,51875119)+1 种基金the Heilongjiang Touyan Teamthe Guangdong Major Project of Basic and Applied Basic Research(2019B030302001)
文摘The momentum wheel assumes a dominant role as an inertial actuator for satellite attitude control systems.Due to the effects of structural aging and external interference,the momentum wheel may experience the gradual emergence of irreversible faults.These fault features will become apparent in the telemetry signal transmitted by the momentum wheel.This paper introduces ADTWformer,a lightweight model for long-term prediction of time series,to analyze the time evolution trend and multi-dimensional data coupling mechanism of satellite momentum wheel faults.Moreover,the incorporation of the approximate Markov blanket with the maximum information coefficient presents a novel methodology for performing correlation analysis,providing significant perspectives from a data-centric standpoint.Ultimately,the creation of an adaptive alarm mechanism allows for the successful attainment of the momentum wheel fault warning by detecting the changes in the health status curves.The analysis methodology outlined in this article has exhibited positive results in identifying instances of satellite momentum wheel failure in two scenarios,thereby showcasing considerable promise for large-scale applications.
基金funded by the National Natural Science Foundation of China(No.52204407)the Natural Science Foundation of Jiangsu Province,China(No.BK20220595)the China Postdoctoral Science Foundation(No.2022M723689)。
文摘The dynamic recrystallization(DRX)behavior and texture formation mechanism in an AZ31 magnesium alloy wheel hub during the spinning process were investigated.Analysis using optical microscopy,electron backscatter diffraction,transmission electron microscopy,and finite element simulation revealed that continuous dynamic recrystallization(CDRX)and grain boundary bulging occurred simultaneously throughout the spinning process,leading to an increased proportion of DRXed grain areas.The newly formed DRXed grains largely retained the orientations of their deformed parent grains.The spinning process had two stages:initially,deformation was driven by basalslip as the roller contacted the alloy and descended to its lowest point.In the later stage,pyramidal<c+a>slips became predominant as additional force was applied along the spinning direction(SD),forming a final texture with the c-axis tilting±15°towards the SD.This texture development led to discernible anisotropy in tensile properties along the SD and the tangential direction(TD).
基金Supported by National Natural Science Foundation of China(Grant No.52175401)Hunan Provincial Postgraduate Scientific Research Innovation Project(Grant No.QL20230244)+1 种基金Enterprise Innovation and Development Joint Program of National Natural Science Foundation of China(Grant No.U20B2032)Hunan Provincial Science and Technology Innovation Program(Grant No.2022RC1050).
文摘Because the grinding temperature is high when grinding using conventional disordered grinding wheels,the grinding quality improvement is limited when using single abrasive ordered grinding wheels,and the wheel preparation process is complex and costly when using microstructured grinding wheels,abrasive groups ordered grinding wheels are widely investigated.However,there is a paucity of systematic analyses and comprehensive reviews focused on abrasive groups ordered grinding wheels.Therefore,this paper defines abrasive groups ordered grinding wheels and classifies them,based on their unique characteristics,into groups such as abrasive blocks ordered grinding wheel,fine grain structured grinding wheel,abrasive clusters ordered grinding wheel,and abrasive fibers ordered grinding wheel.We provide an overview of the latest advances in wheel structures,preparation methods,and abrasive selection for various types of abrasive groups ordered grinding wheels.Furthermore,we conduct a comparative analysis of the existing types,significant advantages,and challenges associated with the four types of abrasive groups ordered grinding wheels.Looking ahead,given the potential of abrasive groups ordered grinding wheels in reducing grinding force and temperature,we recommend further exploration of their application in combination with special processing techniques.This could pave the way for the development of machining processes that are more environmentally friendly,energy-efficient,and precise.
基金financially supported by the National Natural Science Foundation of China(No.1237040868).
文摘In recent years,the development of solid-state lighting devices has increasingly shifted towards high-power laser illumination,making it imperative to develop fluorescent conversion materials with exceptional thermal stability and luminous quality.In this study,we introduced a highly reflective TiO_(2) substrate in combination with a high thermal conductivity AlN substrate to design a Ce:YAG-PiG-TiO_(2)-AlN Film(Ce:YAG PTAF)color converter with outstanding photothermal performance.Remarkably,the thermal conductivity of this material reaches 48.28 W m^(-1) K^(-1).Notably,the optimized PTAF can withstand a high-power output of up to 12.14 W in a static environment,with a maximum luminous flux(LFmax)of 2284.6 lm and maximum luminous efficacy(LEmax)of 222.35 lm W^(-1),showcasing its excellent optical properties.Furthermore,the fabricated Ce:YAG-PiG-TiO_(2)-AlN-Wheel(Ce:YAG PTAW),equipped with a motor operating at 7200 r/min,emits an extraordinary brightness of 4404 lm under 88 W of ultra-high laser irradiation,with stability surpassing that of commercial silicone color wheels,thanks to its superior Li_(2)O-Al_(2)O_(3)-SiO_(2)(LAS)glass system.Interestingly,we designed an innovative spatially separated two-color segmented wheel structure,effectively mitigating the photon reabsorption phenomenon caused by the overlap of the fluorescent powder absorption peaks.When the ratio of Ce:YAG to Ce:GdYAG is 240:120,it yields white light with a color rendering index(CRI)of 80.2,and luminous flux remaining at 3317.8 lm.When encapsulated in a reflective module,it accurately reflects the true color states of objects.These results collectively indicate that both Ce:YAG PTAF and PTAW possess significant application potential in the realm of high-power laser illumination.
