Mesh reflector antennas are the mainstream of large space-borne antennas,and the stretching of the truss achieves their deployment.Currently,the truss is commonly designed to be a single degree of freedom(DOF)deployab...Mesh reflector antennas are the mainstream of large space-borne antennas,and the stretching of the truss achieves their deployment.Currently,the truss is commonly designed to be a single degree of freedom(DOF)deployable mechanism with synchronization constraints.However,each deployable unit’s drive distribution and resistance load are uneven,and the forced synchronization constraints lead to the flexible deformation of rods and difficulties in the deployment scheme design.This paper introduces an asynchronous deployment scheme with a multi-DOF closed-chain deployable truss.The DOF of the truss is calculated,and the kinematic and dynamic models are established,considering the truss’s and cable net’s real-time coupling.An integrated solving algorithm for implicit differential-algebraic equations is proposed to solve the dynamic models.A prototype of a six-unit antenna was fabricated,and the experiment was carried out.The dynamic performances in synchronous and asynchronous deployment schemes are analyzed,and the results show that the cable resistance and truss kinetic energy impact under the asynchronous deployment scheme are minor,and the antenna is more straightforward to deploy.The work provides a new asynchronous deployment scheme and a universal antenna modeling method for dynamic design and performance improvement.展开更多
Head injuries from vehicle collisions,falls,and sports are often the result of complex mechanisms involving both linear and angular forces.This study aims to quantitatively assess the effects of linear and angular for...Head injuries from vehicle collisions,falls,and sports are often the result of complex mechanisms involving both linear and angular forces.This study aims to quantitatively assess the effects of linear and angular force on the severity of traumatic brain injury in rats during collisions.An orthogonal experimental design was employed,facilitating the manipulation of linear velocity,rotational acceleration,and angle(light,medium,and heavy)across 54 rats.24 hours post-injury,magnetic resonance imaging T2-weighted imaging,and diffusion tensor imaging were utilized to detect abnormal brain signals,with the fractional anisotropy value of the corpus callosum serv-ing as the primary injury indicator.Anatomical analyses and immunohistological staining were conducted to measure the amyloid precursor protein(β-APP)accumulation,using integrated optical density as a secondary indicator.Entropy weighting was applied to derive index weights for the injury scoring system.Through analysis guided by analysis of variance and linear regression,it was determined that both linear and angular loadings significantly impacted brain injury severity.Increased rotational acceleration at constant linear velocities correlated with more severe injuries,whereas the rotation angle exhibited minimal effect.Linear velocity emerged as the primary determinant of injury severity,accounting for 91.5%of the variance,while rotational acceleration and rotation angle contributed 6.5%and 0.9%,respectively.These findings offer critical insights for developing protective measures against brain injuries in traffic accidents.展开更多
BACKGROUND Carotid body tumor(CBT)is a chemoreceptor tumor located in the carotid body,accounting for approximately 0.22%of head and neck tumors.Surgery is the main treatment method for the disease.CASE SUMMARY We rev...BACKGROUND Carotid body tumor(CBT)is a chemoreceptor tumor located in the carotid body,accounting for approximately 0.22%of head and neck tumors.Surgery is the main treatment method for the disease.CASE SUMMARY We reviewed the diagnosis and treatment of one patient who had postoperative secondary aggravation of obstructive sleep apnea–hypopnea syndrome(OSAHS)and hypoxia after surgical resection of bilateral CBTs.This patient was admitted,and relevant laboratory and imaging examinations,and polysomnography(PSG)were performed.After the definitive diagnosis,continuous positive airway pressure(CPAP)treatment was given,which achieved good efficacy.CONCLUSION This case suggested that aggravation of OSAHS and hypoxemia is possibly caused by the postoperative complications after bilateral CBTs,and diagnosis by PSG and CPAP treatment are helpful for this patient.展开更多
Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector ...Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector that transmits signals.Smooth deployment is essential for duty services;therefore,accurate and efficient dynamic modeling and analysis of the deployment process are essential.One major challenge is depicting time-varying resistance of the cable network and capturing the cable-truss coupling behavior during the deployment process.This paper proposes a general dynamic analysis methodology for cable-truss coupling.Considering the topological diversity and geometric nonlinearity,the cable network's equilibrium equation is derived,and an explicit expression of the time-varying tension of the boundary cables,which provides the main resistance in truss deployment,is obtained.The deployment dynamic model is established,which considers the coupling effect between the soft cables and deployable truss.The effects of the antenna's driving modes and parameters on the dynamic deployment performance were investigated.A scaled prototype was manufactured,and the deployment experiment was conducted to verify the accuracy of the proposed modeling method.The proposed methodology is suitable for general cable antennas with arbitrary topologies and parameters,providing theoretical guidance for the dynamic performance evaluation of antenna driving schemes.展开更多
The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless ...The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.展开更多
Neural regeneration stands at the forefront of neuroscience,aiming to repair and restore function to damaged neural tissues,particularly within the central nervous system(CNS),where regenerative capacity is inherently...Neural regeneration stands at the forefront of neuroscience,aiming to repair and restore function to damaged neural tissues,particularly within the central nervous system(CNS),where regenerative capacity is inherently limited.However,recent breakthroughs in biotechnology,especially the revolutions in genetic engineering,materials science,multi-omics,and imaging,have promoted the development of neural regeneration.This review highlights the latest cutting-edge technologies driving progress in the field,including optogenetics,chemogenetics,three-dimensional(3D)culture models,gene editing,single-cell sequencing,and 3D imaging.Prospectively,the advancements in artificial intelligence(AI),high-throughput in vivo screening,and brain-computer interface(BCI)technologies promise to accelerate discoveries in neural regeneration further,paving the way for more precise,efficient,and personalized therapeutic strategies.The convergence of these multidisciplinary approaches holds immense potential for developing transformative treatments for neural injuries and neurological disorders,ultimately improving functional recovery.展开更多
Purpose:Intertrochanteric fracture(ITF)classification is crucial for surgical decision-making.However,orthopedic trauma surgeons have shown lower accuracy in ITF classification than expected.The objective of this stud...Purpose:Intertrochanteric fracture(ITF)classification is crucial for surgical decision-making.However,orthopedic trauma surgeons have shown lower accuracy in ITF classification than expected.The objective of this study was to utilize an artificial intelligence(AI)method to improve the accuracy of ITF classification.Methods:We trained a network called YOLOX-SwinT,which is based on the You Only Look Once X(YOLOX)object detection network with Swin Transformer(SwinT)as the backbone architecture,using 762 radiographic ITF examinations as the training set.Subsequently,we recruited 5 senior orthopedic trauma surgeons(SOTS)and 5 junior orthopedic trauma surgeons(JOTS)to classify the 85 original images in the test set,as well as the images with the prediction results of the network model in sequence.Statistical analysis was performed using the SPSS 20.0(IBM Corp.,Armonk,NY,USA)to compare the differences among the SOTS,JOTS,SOTS+AI,JOTS+AI,SOTS+JOTS,and SOTS+JOTS+AI groups.All images were classified according to the AO/OTA 2018 classification system by 2 experienced trauma surgeons and verified by another expert in this field.Based on the actual clinical needs,after discussion,we integrated 8 subgroups into 5 new subgroups,and the dataset was divided into training,validation,and test sets by the ratio of 8:1:1.Results:The mean average precision at the intersection over union(IoU)of 0.5(mAP50)for subgroup detection reached 90.29%.The classification accuracy values of SOTS,JOTS,SOTS+AI,and JOTS+AI groups were 56.24%±4.02%,35.29%±18.07%,79.53%±7.14%,and 71.53%±5.22%,respectively.The paired t-test results showed that the difference between the SOTS and SOTS+AI groups was statistically significant,as well as the difference between the JOTS and JOTS+AI groups,and the SOTS+JOTS and SOTS+JOTS+AI groups.Moreover,the difference between the SOTS+JOTS and SOTS+JOTS+AI groups in each subgroup was statistically significant,with all p<0.05.The independent samples t-test results showed that the difference between the SOTS and JOTS groups was statistically significant,while the difference between the SOTS+AI and JOTS+AI groups was not statistically significant.With the assistance of AI,the subgroup classification accuracy of both SOTS and JOTS was significantly improved,and JOTS achieved the same level as SOTS.Conclusion:In conclusion,the YOLOX-SwinT network algorithm enhances the accuracy of AO/OTA subgroups classification of ITF by orthopedic trauma surgeons.展开更多
Hydraulic servo motors are widely used in aircraft utility systems due to their highefficiency bidirectional variable displacement drive characteristics.However,the displacement changes process leads to severe frictio...Hydraulic servo motors are widely used in aircraft utility systems due to their highefficiency bidirectional variable displacement drive characteristics.However,the displacement changes process leads to severe friction losses between the swashplate and the bearing,and effective solutions are currently lacking.To address this issue,a Hydrodynamic Swashplate-Bearing Pair(HSBP)structure is proposed for hydraulic servo motors,which avoids the direct contact problem of traditional structures.A numerical calculation model for the HSBP is established,the axial displacement phenomenon generated during the reciprocating motion of the swash plate is considered,and a local mobility method is introduced to solve the frictional characteristic pa-rameters of the new friction pair.The analysis and calculation results obtained the influence law of different working condition parameters and structural parameters on the friction characteristics.A quasi-actual friction test bench is developed to simulate the actual motion characteristics of the swashplate,simplifying the testing method for the friction pair.The experimental results show an error of less than10%compared to the calculated results.Additionally,the experimental results demonstrate that the proposed hydrodynamic swashplate bearing structure can effectively reduce the friction force during the displacement adjustment process of hydraulic servo motors by more than 90%compared to traditional swashplate bearing structures.展开更多
Oil is an important strategic material and civil energy.Accurate prediction of oil consumption can provide basis for relevant departments to reasonably arrange crude oil production,oil import and export,and optimize t...Oil is an important strategic material and civil energy.Accurate prediction of oil consumption can provide basis for relevant departments to reasonably arrange crude oil production,oil import and export,and optimize the allocation of social resources.Therefore,a new grey model FENBGM(1,1)is proposed to predict oil consumption in China.Firstly,the grey effect of the traditional GM(1,1)model was transformed into a quadratic equation.Four different parameters were introduced to improve the accuracy of the model,and the new initial conditions were designed by optimizing the initial values by weighted buffer operator.Combined with the reprocessing of the original data,the scheme eliminates the random disturbance effect,improves the stability of the system sequence,and can effectively extract the potential pattern of future development.Secondly,the cumulative order of the new model was optimized by fractional cumulative generation operation.At the same time,the smoothness rate quasi-smoothness condition was introduced to verify the stability of the model,and the particle swarm optimization algorithm(PSO)was used to search the optimal parameters of the model to enhance the adaptability of the model.Based on the above improvements,the new combination prediction model overcomes the limitation of the traditional grey model and obtains more accurate and robust prediction results.Then,taking the petroleum consumption of China's manufacturing industry and transportation,storage and postal industry as an example,this paper verifies the validity of FENBGM(1,1)model,analyzes and forecasts China's crude oil consumption with several commonly used forecasting models,and uses FENBGM(1,1)model to forecast China's oil consumption in the next four years.The results show that FENBGM(1,1)model performs best in all cases.Finally,based on the prediction results of FENBGM(1,1)model,some reasonable suggestions are put forward for China's oil consumption planning.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFB3407103)the National Natural Science Foundation of China(Grant Nos.52175242 and 52175027)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(Grant No.2022QNRC001).
文摘Mesh reflector antennas are the mainstream of large space-borne antennas,and the stretching of the truss achieves their deployment.Currently,the truss is commonly designed to be a single degree of freedom(DOF)deployable mechanism with synchronization constraints.However,each deployable unit’s drive distribution and resistance load are uneven,and the forced synchronization constraints lead to the flexible deformation of rods and difficulties in the deployment scheme design.This paper introduces an asynchronous deployment scheme with a multi-DOF closed-chain deployable truss.The DOF of the truss is calculated,and the kinematic and dynamic models are established,considering the truss’s and cable net’s real-time coupling.An integrated solving algorithm for implicit differential-algebraic equations is proposed to solve the dynamic models.A prototype of a six-unit antenna was fabricated,and the experiment was carried out.The dynamic performances in synchronous and asynchronous deployment schemes are analyzed,and the results show that the cable resistance and truss kinetic energy impact under the asynchronous deployment scheme are minor,and the antenna is more straightforward to deploy.The work provides a new asynchronous deployment scheme and a universal antenna modeling method for dynamic design and performance improvement.
基金supported by the National Nature Science Foundation of China(Grant No.32171305)Chongqing Technology Innova-tion and Application Development Project(Grant No.CSTB2023YSZX-JSX0003)Chongqing Municipal“Doctoral Express”Research Project(Grant No.CSTB2022BSXM-JCX0013).
文摘Head injuries from vehicle collisions,falls,and sports are often the result of complex mechanisms involving both linear and angular forces.This study aims to quantitatively assess the effects of linear and angular force on the severity of traumatic brain injury in rats during collisions.An orthogonal experimental design was employed,facilitating the manipulation of linear velocity,rotational acceleration,and angle(light,medium,and heavy)across 54 rats.24 hours post-injury,magnetic resonance imaging T2-weighted imaging,and diffusion tensor imaging were utilized to detect abnormal brain signals,with the fractional anisotropy value of the corpus callosum serv-ing as the primary injury indicator.Anatomical analyses and immunohistological staining were conducted to measure the amyloid precursor protein(β-APP)accumulation,using integrated optical density as a secondary indicator.Entropy weighting was applied to derive index weights for the injury scoring system.Through analysis guided by analysis of variance and linear regression,it was determined that both linear and angular loadings significantly impacted brain injury severity.Increased rotational acceleration at constant linear velocities correlated with more severe injuries,whereas the rotation angle exhibited minimal effect.Linear velocity emerged as the primary determinant of injury severity,accounting for 91.5%of the variance,while rotational acceleration and rotation angle contributed 6.5%and 0.9%,respectively.These findings offer critical insights for developing protective measures against brain injuries in traffic accidents.
文摘BACKGROUND Carotid body tumor(CBT)is a chemoreceptor tumor located in the carotid body,accounting for approximately 0.22%of head and neck tumors.Surgery is the main treatment method for the disease.CASE SUMMARY We reviewed the diagnosis and treatment of one patient who had postoperative secondary aggravation of obstructive sleep apnea–hypopnea syndrome(OSAHS)and hypoxia after surgical resection of bilateral CBTs.This patient was admitted,and relevant laboratory and imaging examinations,and polysomnography(PSG)were performed.After the definitive diagnosis,continuous positive airway pressure(CPAP)treatment was given,which achieved good efficacy.CONCLUSION This case suggested that aggravation of OSAHS and hypoxemia is possibly caused by the postoperative complications after bilateral CBTs,and diagnosis by PSG and CPAP treatment are helpful for this patient.
基金Supported by National Key R&D Program of China (Grant No.2023YFB3407103)National Natural Science Foundation of China (Grant Nos.52175242,52175027)Young Elite Scientists Sponsorship Program by CAST (Grant No.2022QNRC001)。
文摘Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector that transmits signals.Smooth deployment is essential for duty services;therefore,accurate and efficient dynamic modeling and analysis of the deployment process are essential.One major challenge is depicting time-varying resistance of the cable network and capturing the cable-truss coupling behavior during the deployment process.This paper proposes a general dynamic analysis methodology for cable-truss coupling.Considering the topological diversity and geometric nonlinearity,the cable network's equilibrium equation is derived,and an explicit expression of the time-varying tension of the boundary cables,which provides the main resistance in truss deployment,is obtained.The deployment dynamic model is established,which considers the coupling effect between the soft cables and deployable truss.The effects of the antenna's driving modes and parameters on the dynamic deployment performance were investigated.A scaled prototype was manufactured,and the deployment experiment was conducted to verify the accuracy of the proposed modeling method.The proposed methodology is suitable for general cable antennas with arbitrary topologies and parameters,providing theoretical guidance for the dynamic performance evaluation of antenna driving schemes.
文摘The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.
基金supported by grants from the Pioneer and Leading Goose R&D Program of Zhejiang Province,China(2024C03028)the Leading Innovation and Entrepreneurship Team Program of Zhejiang Province,China(2023R01005).
文摘Neural regeneration stands at the forefront of neuroscience,aiming to repair and restore function to damaged neural tissues,particularly within the central nervous system(CNS),where regenerative capacity is inherently limited.However,recent breakthroughs in biotechnology,especially the revolutions in genetic engineering,materials science,multi-omics,and imaging,have promoted the development of neural regeneration.This review highlights the latest cutting-edge technologies driving progress in the field,including optogenetics,chemogenetics,three-dimensional(3D)culture models,gene editing,single-cell sequencing,and 3D imaging.Prospectively,the advancements in artificial intelligence(AI),high-throughput in vivo screening,and brain-computer interface(BCI)technologies promise to accelerate discoveries in neural regeneration further,paving the way for more precise,efficient,and personalized therapeutic strategies.The convergence of these multidisciplinary approaches holds immense potential for developing transformative treatments for neural injuries and neurological disorders,ultimately improving functional recovery.
基金supported by the Technological Innovation and Application Development Project of Chongqing(CSTB2021TIADKPX0074)the Chongqing Science and Health Joint Project(2024MSXM084)the Innovative Capability Enhancement programme of Army Medical Center of PLA(ZXYZZKY01).
文摘Purpose:Intertrochanteric fracture(ITF)classification is crucial for surgical decision-making.However,orthopedic trauma surgeons have shown lower accuracy in ITF classification than expected.The objective of this study was to utilize an artificial intelligence(AI)method to improve the accuracy of ITF classification.Methods:We trained a network called YOLOX-SwinT,which is based on the You Only Look Once X(YOLOX)object detection network with Swin Transformer(SwinT)as the backbone architecture,using 762 radiographic ITF examinations as the training set.Subsequently,we recruited 5 senior orthopedic trauma surgeons(SOTS)and 5 junior orthopedic trauma surgeons(JOTS)to classify the 85 original images in the test set,as well as the images with the prediction results of the network model in sequence.Statistical analysis was performed using the SPSS 20.0(IBM Corp.,Armonk,NY,USA)to compare the differences among the SOTS,JOTS,SOTS+AI,JOTS+AI,SOTS+JOTS,and SOTS+JOTS+AI groups.All images were classified according to the AO/OTA 2018 classification system by 2 experienced trauma surgeons and verified by another expert in this field.Based on the actual clinical needs,after discussion,we integrated 8 subgroups into 5 new subgroups,and the dataset was divided into training,validation,and test sets by the ratio of 8:1:1.Results:The mean average precision at the intersection over union(IoU)of 0.5(mAP50)for subgroup detection reached 90.29%.The classification accuracy values of SOTS,JOTS,SOTS+AI,and JOTS+AI groups were 56.24%±4.02%,35.29%±18.07%,79.53%±7.14%,and 71.53%±5.22%,respectively.The paired t-test results showed that the difference between the SOTS and SOTS+AI groups was statistically significant,as well as the difference between the JOTS and JOTS+AI groups,and the SOTS+JOTS and SOTS+JOTS+AI groups.Moreover,the difference between the SOTS+JOTS and SOTS+JOTS+AI groups in each subgroup was statistically significant,with all p<0.05.The independent samples t-test results showed that the difference between the SOTS and JOTS groups was statistically significant,while the difference between the SOTS+AI and JOTS+AI groups was not statistically significant.With the assistance of AI,the subgroup classification accuracy of both SOTS and JOTS was significantly improved,and JOTS achieved the same level as SOTS.Conclusion:In conclusion,the YOLOX-SwinT network algorithm enhances the accuracy of AO/OTA subgroups classification of ITF by orthopedic trauma surgeons.
基金supported by the National Natural Science Foundation of China(No.52205045)the Natural Science Foundation of Hebei Province,China(No.E2024203244)the Aeronautical Science Foundation of China(No.2022Z029051001)。
文摘Hydraulic servo motors are widely used in aircraft utility systems due to their highefficiency bidirectional variable displacement drive characteristics.However,the displacement changes process leads to severe friction losses between the swashplate and the bearing,and effective solutions are currently lacking.To address this issue,a Hydrodynamic Swashplate-Bearing Pair(HSBP)structure is proposed for hydraulic servo motors,which avoids the direct contact problem of traditional structures.A numerical calculation model for the HSBP is established,the axial displacement phenomenon generated during the reciprocating motion of the swash plate is considered,and a local mobility method is introduced to solve the frictional characteristic pa-rameters of the new friction pair.The analysis and calculation results obtained the influence law of different working condition parameters and structural parameters on the friction characteristics.A quasi-actual friction test bench is developed to simulate the actual motion characteristics of the swashplate,simplifying the testing method for the friction pair.The experimental results show an error of less than10%compared to the calculated results.Additionally,the experimental results demonstrate that the proposed hydrodynamic swashplate bearing structure can effectively reduce the friction force during the displacement adjustment process of hydraulic servo motors by more than 90%compared to traditional swashplate bearing structures.
基金This work was supported by the National Natural Science Foundation of China(No.71901184,No.72001181).
文摘Oil is an important strategic material and civil energy.Accurate prediction of oil consumption can provide basis for relevant departments to reasonably arrange crude oil production,oil import and export,and optimize the allocation of social resources.Therefore,a new grey model FENBGM(1,1)is proposed to predict oil consumption in China.Firstly,the grey effect of the traditional GM(1,1)model was transformed into a quadratic equation.Four different parameters were introduced to improve the accuracy of the model,and the new initial conditions were designed by optimizing the initial values by weighted buffer operator.Combined with the reprocessing of the original data,the scheme eliminates the random disturbance effect,improves the stability of the system sequence,and can effectively extract the potential pattern of future development.Secondly,the cumulative order of the new model was optimized by fractional cumulative generation operation.At the same time,the smoothness rate quasi-smoothness condition was introduced to verify the stability of the model,and the particle swarm optimization algorithm(PSO)was used to search the optimal parameters of the model to enhance the adaptability of the model.Based on the above improvements,the new combination prediction model overcomes the limitation of the traditional grey model and obtains more accurate and robust prediction results.Then,taking the petroleum consumption of China's manufacturing industry and transportation,storage and postal industry as an example,this paper verifies the validity of FENBGM(1,1)model,analyzes and forecasts China's crude oil consumption with several commonly used forecasting models,and uses FENBGM(1,1)model to forecast China's oil consumption in the next four years.The results show that FENBGM(1,1)model performs best in all cases.Finally,based on the prediction results of FENBGM(1,1)model,some reasonable suggestions are put forward for China's oil consumption planning.
