The sauropodomorph Thecodontosaurus caducus and theropod Coelophysis bauri are the earliest known dinosaurs with postcranial skeletal pneumaticity.In both taxa,postcranial pneumatic features are confined to the cervic...The sauropodomorph Thecodontosaurus caducus and theropod Coelophysis bauri are the earliest known dinosaurs with postcranial skeletal pneumaticity.In both taxa,postcranial pneumatic features are confined to the cervical vertebrae.This distribution of pneumaticity in the skeleton is most consistent with pneumatization by diverticula of cervical air sacs similar to those of birds.Other hypotheses,including pneumatization by diverticula of the lungs,larynx and trachea,or cranial air spaces,are less well-supported.展开更多
Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on...Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.展开更多
Fecal incontinence(FI),which can arise from various pathogenic mechanisms,has attracted considerable attention worldwide.Despite its importance,the reproduction of the defecatory system to study the mechanisms of FI r...Fecal incontinence(FI),which can arise from various pathogenic mechanisms,has attracted considerable attention worldwide.Despite its importance,the reproduction of the defecatory system to study the mechanisms of FI remains limited,largely because of social stigma and being considered inappropriate.Inspired by the rectum’s functionalities,we developed a soft robotic system that includes a power supply,pressure sensors,data acquisition systems,a flushing mechanism,stages,and a rectal module.Specifically,the innovative soft rectal module includes actuators inspired by sphincter muscles,both soft and rigid covers,and a soft rectum mold.The rectal mold,which was fabricated from materials that mimic human rectal tissue,was produced using a mold replication fabrication method.Both the soft and rigid components of the mold were created using three-dimensional(3D)printing technology.In addition,the sphincter muscle-inspired actuators featured double-layer pouch structures that were modeled and optimized based on multilayer perceptron methods to obtain a high contraction ratio(100%),generate high pressure(9.8 kPa),and have a short recovery time(3 s).Upon assembly,this defecation robot could smoothly expel liquid feces,perform controlled solid fecal cutting,and defecate extremely solid long feces,thus closely replicating the functions of the human rectum and anal canal.This defecation robot has the potential to facilitate human understanding of the complex defecation system and contribute to the development of improved quality-of-life devices related to defecation.展开更多
AIM:To evaluate visual outcomes of pars plana vitrectomy(PPV)combined with tissue plasminogen activator(tPA)-induced clot lysis and pneumatic displacement for submacular hemorrhage(SMH)in a cohort of closed-globe trau...AIM:To evaluate visual outcomes of pars plana vitrectomy(PPV)combined with tissue plasminogen activator(tPA)-induced clot lysis and pneumatic displacement for submacular hemorrhage(SMH)in a cohort of closed-globe trauma patients.METHODS:A retrospective,multicenter interventional case series involving 7 eyes of 7 patients who underwent PPV with subretinal tPA administration for SMH secondary to closed-globe injury were conducted.The primary outcome measure was the change in Snellen visual acuity.RESULTS:The mean age of patients was 32y(range:21-51y),with a mean follow-up duration of 4.6mo(range:1.1-14.9mo).The average best-corrected visual acuity(BCVA)was 20/1020 at baseline and 20/114 at the final visit,respectively(P=0.025).Preoperative BCVA was not a significant predictor of final BCVA(r=0.102,P=0.827).Final BCVA did not differ significantly between patients who underwent PPV within 14d of symptom onset and those who underwent surgery after 14d(P=0.57).All eyes received SF6 or C3F8 gas tamponade.CONCLUSION:Surgical intervention involving tPAmediated clot lysis and pneumatic displacement may yield visual benefits in trauma-induced SMH without underlying retinal vascular disease;however,larger prospective studies are warranted to confirm these findings.展开更多
Four-dimensional(4D)printing represents a groundbreaking advancement in manufacturing,yet a persistent challenge is the limited number of stable configurations achievable through spontaneous shape reconstruction.Herei...Four-dimensional(4D)printing represents a groundbreaking advancement in manufacturing,yet a persistent challenge is the limited number of stable configurations achievable through spontaneous shape reconstruction.Herein,we present a novel 4D printing mechanism that utilizes self-adjustable gas pressure to facilitate a wide range of spontaneous and stable multi-shape transformations.The gas is precisely released at designated spatial locations through strategic temperature-controlled degradation of a solid material,which is printed and distributed as needed at the voxel level within a specially designed multi-material structure,consisting of a low degradation temperature material(LDTM),a high degradation temperature soft material(HDTSM),and a high degradation temperature hard material(HDTHM).Each shape configuration is determined and locked in by the maximum temperature experienced during its thermal history.Notably,this shape retains its form robustly,independently of subsequent temperature changes,until a higher temperature threshold is reached,at which point a new shape configuration is triggered.These shapes exhibit a remarkable temperature memory effect,permanently recording the peak temperature reached in their thermal history.Our study comprehensively investigates the underlying principles and key parameters that influence deformation.We present a series of examples demonstrating complex multi-shape transformations modulated by temperature,supported by finite element simulations.This advance in 4D printing has the potential to significantly enhance its functional capabilities,performance,and applicability,opening up new horizons in additive manufacturing and design.展开更多
Pneumatic soft robots have undergone significant advancements in recent years.However,the majority of robot motion control still relies on electronic computers to regulate the valves and air pumps.Despite the potentia...Pneumatic soft robots have undergone significant advancements in recent years.However,the majority of robot motion control still relies on electronic computers to regulate the valves and air pumps.Despite the potential reduction in controller dependency by utilizing soft pneumatic oscillators,challenges such as low flow rates,complex manufacturing processes,and lack of adjustment ability persist.Inspired by the geckos'spine,we propose a Spinal Bistable Oscillator(SBO)that operates without discrete components or electronic control hardware,achieving stable oscillatory motion under constant air pressure.This oscillator employs a soft control valve and lagging pin,which can switch the direction of airflow conduction based on the oscillation angle of the spine.Different types of actuators can be controlled using a series connection.In this study,the effective working range of the soft control valve,influence of the spring pretension force on the torque during oscillation,and effect of different throttle tube lengths on the oscillation frequency were investigated.Furthermore,a self-crawling robot was developed.Experimental results demonstrate that the robot can crawl at speeds ranging from 3.6 to 5.7 mm/s(or 3.1 to 4.9 body length/min)and overcome its own gravity(with a weight of 165 g)to climb vertically.The SBO proposed in this study exhibits characteristics of lightweight,low cost,high oscillation torque,and tunable frequency.It holds promise for application in joint control of future pneumatic soft robots.展开更多
Pneumatic down-the-hole hammer, serving as rock-breaking tool, possesses appeal for directional drilling due to its high rate of penetration. However, corresponding experimental studies on existing hammers for directi...Pneumatic down-the-hole hammer, serving as rock-breaking tool, possesses appeal for directional drilling due to its high rate of penetration. However, corresponding experimental studies on existing hammers for directional drilling have rarely been reported, and a model for evaluating their output performance is absent. This study proposes a novel structure of self-rotating pneumatic hammer(NSH)with a built-in rotational mechanism, which converts partial impact energy of the piston to rotate the drill bit and, consequently, enables dual functions of impact and rotate drill bit. The energy is converted via a screw key-groove mechanism, and the wedge-shaped teeth mechanism ensures that the drill bit rotates clockwise during the piston moves downward. The computational fluid dynamics method is applied to simulate the dynamic response of airflow and piston during the operation of Φ127NSH.Meanwhile, a test bench is established to record data concerning chamber pressure and piston displacement, as well as recording its operational status and rock fragmentation during drilling into granite. The results showed that the maximum error between simulated and experimental data is 8.2%.The Φ127NSH successfully achieves dual impact and rotary drilling functions, and granite smoothly feeds and forms a continuous shear rock zone. In addition, the effects of torque load, engagement distance in rotation sleeves, and well deviation angle towards the performance of NSH were studied in detail. The designed Φ127NSH operates at an impact velocity of 3.98 m/s, impact frequency of 12.55 Hz, and rotational speed of 29.51 r/min under a mass-flow rate of 0.18 kg/s, torque load of 400 N·m, engagement distance of 40 mm, and well deviation angle of 0°. The torque load adversely affects the NSH output performance. Increasing the engagement distance improves impact performance while reducing rotational performance. The performance variation of the NSH is minimal when drilling directional wells with varying deviation angles.展开更多
Continuum robots have been a hot topic in recent years due to their intrinsic features of agility,flexibility,and safety.To successfully deploy continuum robots in practical applications,further enhancements in variab...Continuum robots have been a hot topic in recent years due to their intrinsic features of agility,flexibility,and safety.To successfully deploy continuum robots in practical applications,further enhancements in variable stiffness,decoupled motion,and embedded sensing are highly desirable.Since continuum robots are usually composed of multiple joints assembled in series,their mechanical properties and performance will certainly rely on the connected joints.This paper proposes a motion-decoupled variable stiffness-decoupled pneumatic rigid-flexible hybrid joint(RFHJ),which is modular designed and integrated with a rigid hinge,a stiffness-tuning module,and soft actuators.The soft pneumatic muscle actuators are pre-stretched during assembly,ensuring the stable initial state of RFHJ.A novel musculature-mounting configuration is also presented,which enables RFHJs to achieve independent motions in two orthogonal planes.Furthermore,the variable stiffness module is embedded in the RFHJ’s structure to offer real-time and independent stiffness tunability across multiple scales in two perpendicular directions.The proposed RFHJ makes most of the advantages of soft continuum robots and conventional rigid serial robots by introducing a hybrid structure to provide both safe human-robot interaction(HRI),accurate control and reliable stiffness variation,presenting promising potentials for robotic systems,which have been theoretically proved and experimentally verified on the physical prototype.The experimental results also indicate that the developed RFHJ can work with variable stiffness ranging in[1.2,49.9]N·m/rad.A variable stiffness rigid-flexible hybrid continuum arm(RFHA)is designed with three RFHJs in series.Primary tests on the developed RFHA prototype demonstrate that it has the characteristics of decoupled driving,bidirectional stiffness tunability and self-stability.展开更多
The complex dense-phase pneumatic conveying of pulverized coal process was studied using an electrical capacitance tomography(ECT) signal that represented the motion characteristics of gas-solid two-phase flow. The fl...The complex dense-phase pneumatic conveying of pulverized coal process was studied using an electrical capacitance tomography(ECT) signal that represented the motion characteristics of gas-solid two-phase flow. The fluctuation characteristics of conveying process signals are inseparable from the flow pattern. The denoised ECT signal and noise signal were obtained by db2 wavelet analysis. It was found that all noise signals were white Gaussian noise. Based on the assumption of the equal probability distribution of pulverized coal concentration, this paper proved that the time series distribution of pulverized coal concentration in the pipeline should obey the normal distribution. Furthermore, through the analysis of the distribution characteristics of the power spectral density function of denoised ECT signals of four flow patterns, they were α-dimensional fractal Brownian motion(fBm) signals, and the parameter α was estimated by the detrended fluctuation analysis. Based on the fBm characteristics of denoised ECT signals and white Gaussian noise, this paper proposed a method for calculating the pulverized coal concentration in the dense-phase pneumatic conveying. In addition to the method of concentration estimation with the significance of engineering guidance, this research can help people to further understand essential characteristics of ECT signals in the dense-phase pneumatic conveying.展开更多
Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using li...Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using linear PAMs(LPAMs)designed to mimic human skeletal muscle.LPAMs have considerable potential for wearable applications and can be integrated into soft wearable robotic systems.Due to their inherent compliance,excellent human-robot interaction,safety,and low cost,LPAMs are considered potential alternatives as actuator components in the construction of wearable robots.This review presents a comprehensive overview of the bio-inspired design of LPAMs and their wearable applications.The biomechanics of human skeletal muscle,including anatomy,morphology,and biomechanical characterization,is analyzed to provide design inspirations for LPAMs and determine the assistance requirements of LPAM-based wearable robots.Herein,LPAMs are classified into four categories based on their structural shapes,including cylindrical-shaped muscles,flat-shaped muscles,fold-shaped muscles,and muscles with other shapes.In addition,this review provides an overview of the diverse physical interfaces utilized in wearable robots and presents a comparative analysis of the actuation characteristics of LPAMs and the assistance performance of LPAM-based wearable robots.This analysis was conducted in consideration of several key metrics,including the contraction ratio,maximum force,specific force,response frequency,assistive torque/bodyweight,and net metabolic cost.Finally,this review summarizes the ongoing challenges and future research directions.展开更多
Background The middle ear pneumatic system(MEPS)supports pressure balance,essential for sound conduction.Its volume and surface area are key indicators of pneumatization and ventilation,yet their specific contribution...Background The middle ear pneumatic system(MEPS)supports pressure balance,essential for sound conduction.Its volume and surface area are key indicators of pneumatization and ventilation,yet their specific contributions to pressure regulation need further exploration.Objective To evaluate the accuracy and sensitivity of parameters characterizing the MEPS,including volume(V),surface area(S),and surface-area-to-volume ratio(S/V),in normal ears.Materials and Methods We collected CT images of the temporal bone from 63 normal ears for this study.The volume(V),surface area(S),and surface-area-to-volume ratio(S/V)of the MEPS were measured and calculated using three-dimensional reconstruction technology.Statistical methods were used to process the data and determine the 95%reference range for the S,V,and S/V of the MEPS in the normal ear.At the same time,we analyzed the impact of differences in gender and the left and right sides on the measurements.Results The 95%reference values for the S,V,and S/V of the MEPS in normal ears were 1057.10~18239.16 mm²,609.16~9854.11 mm^(3),and 1.39~2.52 mm^(-1) respectively.There were no significant differences in the measurements between genders and between the left and right sides.Conclusions and Significance This study has established the 95%reference values for the S,V,and S/V of the MEPS in normal ears,which were 1057.10-18239.16 mm²,609.16-9854.11 mm^(3),and 1.39-2.52 mm^(-1) respectively.We found that while there is a wide variation in the V values among normal ears,there is less variability in the S/V values.This structural characteristic suggests that changes in the S/V value may have a more significant impact on the balance of middle ear pressure,and it provides important reference data for the construction and functional reconstruction of three-dimensional models of the MEPS.These findings may aid in diagnosing middle ear disorders,such as otitis media with effusion,and guide interventions to restore pressure balance.展开更多
Because of significantly changed load and complex and variable driving road conditions of commercial vehicles,pneumatic suspension with lower natural frequencies is widely used in commercial vehicle suspension system....Because of significantly changed load and complex and variable driving road conditions of commercial vehicles,pneumatic suspension with lower natural frequencies is widely used in commercial vehicle suspension system.How ever,traditional pneumatic suspension system is hardly to respond the greatly changed load of commercial vehicles To address this issue,a new Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension(GIQZSPS)is presented in this paper to improve the vibration isolation performance of commercial vehicle suspension systems under frequent load changes.This new structure adds negative stiffness air chambers on traditional pneumatic suspension to reduce the natural frequency of the suspension.It can adapt to different loads and road conditions by adjusting the solenoid valves between the negative stiffness air chambers.Firstly,a nonlinear mechanical model including the dimensionless stiffness characteristic and interconnected pipeline model is derived for GIQZSPS system.By the nonlinear mechanical model of GIQZSPS system,the force transmissibility rate is chosen as the evaluation index to analyze characteristics.Furthermore,a testing bench simulating 1/4 GIQZSPS system is designed,and the testing analysis of the model validation and isolating performance is carried out.The results show that compared to traditional pneumatic suspension,the GIQZSPS designed in the article has a lower natural frequency.And the system can achieve better vibration isolation performance under different load states by switching the solenoid valves between air chambers.展开更多
The pneumatic probe is widely used for contact measurements in turbomachinery flow field research.However,it inevitably interferes with the original flow field,leading to additional errors,particularly in wake flow fi...The pneumatic probe is widely used for contact measurements in turbomachinery flow field research.However,it inevitably interferes with the original flow field,leading to additional errors,particularly in wake flow fields or transonic regions with significant pressure gradients.This study employed Reynolds-Averaged Navier-Stokes delete and high-fidelity numerical simulation to investigate the impact of an inserted pneumatic probe on the wake flow field of a transonic turbine blade and compared it to the baseline flow field.Results indicate that the probe causes the shock waves premature occurrence in the high subsonic wake region near the turbine blade trailing edge.These shock waves affect vortex shedding by thickening the boundary layer near the trailing edge and changing the shedding pattern from high-frequency-low-energy to low-frequencyhigh-energy.In addition,the extra flow loss is incurred,and the blade's heat transfer characteristic is changed.This research provides a reference for testing experiments in complex transonic flow fields,guiding experimental researchers to minimize instrument interference with the original flow field.展开更多
Pneumatic conveying technology,as an efficient material transportation method,has been widely used in various industrial fields.To study the powder transportation in horizontal ash conveying pipes,this study relies on...Pneumatic conveying technology,as an efficient material transportation method,has been widely used in various industrial fields.To study the powder transportation in horizontal ash conveying pipes,this study relies on the Computational Particle Fluid Dynamics(CPFD)numerical method.The characteristics of the gas-solid two-phase flow under continuous air supply conditions are analyzed,and the effects on particle movement of factors such as feed port spacing,inlet air velocity,and the number of discharge ports are explored accordingly.The research results show that when the inlet velocity is 5 m/s,adjacent discharged particles come into contact after 8 s.As the inlet air velocity increases,the contact time between adjacent discharge ports is shortened.When the feed port spacing increases from 0.5 to 2 m,the dust accumulation thickness decreases by about 0.6 times.Additionally,when the spacing reaches a certain value,the rate of decrease in dust accumulation thickness begins to diminish.展开更多
●AIM:To evaluate the efficacy of pneumatic retinopexy(PR)in patients undergoing PR as primary treatment for rhegmatogenous retinal detachment(RRD)and analyze the factors associated with success and failure in the stu...●AIM:To evaluate the efficacy of pneumatic retinopexy(PR)in patients undergoing PR as primary treatment for rhegmatogenous retinal detachment(RRD)and analyze the factors associated with success and failure in the studied population.●METHODS:A retrospective chart review was done of patients with RRD treated with PR as primary management method treated at New York Eye and Ear Infirmary of Mount Sinai between January 2017 and December 2021.Primary outcome measured success or failure of PR.Secondary outcome measured best corrected visual acuity(BCVA)after PR.A separate risk analysis was done to identify and stratify risks associated with success and failure of PR.●RESULTS:A total of 179 eyes from 179 patients were included for final analysis.The 83 patients(46.37%)achieved anatomical reattachment of the retina after primary PR with no need for additional surgery.The 96 patients(53.63%)had a failed primary PR and required a PPV and 6 of them required pars plana vitrectomy(PPV)with scleral buckle(SB).In total,19 cases(10.61%)were done as temporizing pneumatics,18(94.74%)underwent PPV,and 1(5.26%)did not require further intervention.The visual acuities at postoperative month 1(POM1)for patients who underwent primary PR successfully and for those that underwent PPV after,were 0.58(20/80)and 1.03(20/200)respectively.Patients who met Pneumatic Retinopexy Versus Vitrectomy for the Management of Primary Rhegmatogenous Retinal Detachment Outcomes Randomized Trial(PIVOT)criteria had a statistically significant decreased risk of primary PR failing(hazard ratio 0.29,P=0.00).Majority of missed or new breaks were found superotemporally.●CONCLUSION:PR is a good treatment option for treating RRDs in patients that meet PIVOT criteria and can be conducted as a temporizing measure.PIVOT criteria and fovea on status decrease the risk of PR failure.展开更多
Achalasia can significantly impair the quality of life.The clinical presentation typically includes dysphagia to both solids and liquids,chest pain,and regurgitation.Diagnosis can be delayed in patients with atypical ...Achalasia can significantly impair the quality of life.The clinical presentation typically includes dysphagia to both solids and liquids,chest pain,and regurgitation.Diagnosis can be delayed in patients with atypical presentations,and they might receive a wrong diagnosis,such as gastroesophageal reflux disease(GERD),owing to overlapping symptoms of both disorders.Although the cause of achalasia is poorly understood,its impact on the motility of the esophagus and gastroesophageal junction is well established.Several treatment modalities have been utilized,with the most common being surgical Heller myotomy with concomitant fundoplication and pneumatic balloon dilatation.Recently,peroral endoscopic myotomy(POEM)has gained popularity as an effective treatment for achalasia,despite a relatively high incidence of GERD occurring after treatment compared to other modalities.The magnitude of post-POEM GERD depends on its definition and is influenced by patient and procedure-related factors.The longterm sequelae of post-POEM GERD are yet to be determined,but it appears to have a benign course and is usually manageable with clinically available modalities.Identifying risk factors for post-POEM GERD and modifying the POEM procedure in selected patients may improve the overall success of this technique.展开更多
The accurate parameters measurement of the flow field between the stages for axial compressors is a significant demand.This paper proposes an axial compressor inter-stage flow field high-precision test system,which ma...The accurate parameters measurement of the flow field between the stages for axial compressors is a significant demand.This paper proposes an axial compressor inter-stage flow field high-precision test system,which mainly consists of a probe motion scanning mechanism,fully automated test control software,and data processing methods.Iterative correction is applied to the original readings obtained from the scanning tests to enhance testing accuracy.Using this test system,detailed tests are conducted on a 1.5-stage subsonic axial compressor under different operating conditions.The test results effectively captured the impact of surface roughness and tip clearance variations on compressor performance.The distribution characteristics of parameters measured in inter-stage sections can characterize the effects of blade wake area and changes in aerodynamic performance at different blade heights.The developed test system can be extended to multi-stage compressors.展开更多
Introduction: Mechanism of male androgenic alopecia (MAGA) is complex and leads to an excessive hair shedding and decreased hair density. Oral, topical, and injectable autologous treatments demonstrate ability to stim...Introduction: Mechanism of male androgenic alopecia (MAGA) is complex and leads to an excessive hair shedding and decreased hair density. Oral, topical, and injectable autologous treatments demonstrate ability to stimulate hair re-growth, but the response is suboptimal or plateaus off. Synthetic combination of the peptide complex and hyaluronic acid (P-HA) demonstrated hair regrowth in alopecia patients. Electronically-operated pneumatic injections (EPI) generate micro-trauma in the dermis and under wound-healing conditions may enhance regeneration effect of P-HA. Methods: Subjects seeking improvement of their male pattern hair loss (Hamilton-Norwood type 2-4) received the P-HA treatments through EPI. The course included 4 treatments every two weeks over the 8-week period. In 6 months, the hair growth was assessed comparative to baseline by global clinical photography and digital phototrichograms. The treatment safety and tolerability were documented through the whole study period. Results: Twelve men (30-45 years old) completed the treatment course with high tolerability and without adverse events. Post-treatment assessment of the previously bald areas showed improved coverage on the clinical photographs. The phototrichograms demonstrated statistically significant increase in terminal hair density by 36%, cumulative hair thickness by 37%, and follicular units by 20%;all contributing to a 38% increase in cumulated hair density (all p Conclusion: Electronic pneumatic injections are well tolerated and can be safely used for the needle-free administration of the peptide-hyaluronic acid combination in MAGA therapy. We achieved significant hair re-densification in the balding scalp. The exact role of the EPI-induced impact in the hair re-growth mechanism remains to be ascertained. .展开更多
The analysis of the characteristics of the cushion process of the pneumatic cushion cylinder is presented, and the nonlinear model of pneumatic cushion cylinders is built in the form of nonlinear differential equation...The analysis of the characteristics of the cushion process of the pneumatic cushion cylinder is presented, and the nonlinear model of pneumatic cushion cylinders is built in the form of nonlinear differential equations. Besides, through the simulation of the pressure in the cushion chamber, the characteristics of the pneumatic cushion cylinder are obtained, which helps to understand the performance of the pneumatic cushion cylinder and improve or design the better cushion structure.展开更多
文摘The sauropodomorph Thecodontosaurus caducus and theropod Coelophysis bauri are the earliest known dinosaurs with postcranial skeletal pneumaticity.In both taxa,postcranial pneumatic features are confined to the cervical vertebrae.This distribution of pneumaticity in the skeleton is most consistent with pneumatization by diverticula of cervical air sacs similar to those of birds.Other hypotheses,including pneumatization by diverticula of the lungs,larynx and trachea,or cranial air spaces,are less well-supported.
基金supported by the Strategic Priority Program of the Chinese Academy of Sciences(XDB0470303)the National Key R&D Program of China(2022YFB4600102and 2023YFE0209900)+4 种基金the National Natural Science Foundation of China(52175201 and 51935012)the science and technology projects of Gansu province(22JR5RA093,24JRRA044,24YFFA014 and 24ZDGA014)the Innovation and Entrepreneurship Team Project of YEDA(2021TD007)the special supporting project for provincial leading talents of Yantaithe Taishan Scholars Program。
文摘Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.
基金supported by Grant-in-Aid for Scientific Research on Innovative Areas from the Japan Society for the Promotion of Science(Nos.18H05473 and 23K13290).
文摘Fecal incontinence(FI),which can arise from various pathogenic mechanisms,has attracted considerable attention worldwide.Despite its importance,the reproduction of the defecatory system to study the mechanisms of FI remains limited,largely because of social stigma and being considered inappropriate.Inspired by the rectum’s functionalities,we developed a soft robotic system that includes a power supply,pressure sensors,data acquisition systems,a flushing mechanism,stages,and a rectal module.Specifically,the innovative soft rectal module includes actuators inspired by sphincter muscles,both soft and rigid covers,and a soft rectum mold.The rectal mold,which was fabricated from materials that mimic human rectal tissue,was produced using a mold replication fabrication method.Both the soft and rigid components of the mold were created using three-dimensional(3D)printing technology.In addition,the sphincter muscle-inspired actuators featured double-layer pouch structures that were modeled and optimized based on multilayer perceptron methods to obtain a high contraction ratio(100%),generate high pressure(9.8 kPa),and have a short recovery time(3 s).Upon assembly,this defecation robot could smoothly expel liquid feces,perform controlled solid fecal cutting,and defecate extremely solid long feces,thus closely replicating the functions of the human rectum and anal canal.This defecation robot has the potential to facilitate human understanding of the complex defecation system and contribute to the development of improved quality-of-life devices related to defecation.
基金Supportea by DeNardo Education and Research Foundation GrantJeffrey T.Fort Innovation Fund+3 种基金Siteman Retina Research FundResearch to Prevent Blindness IncGetahun H is supported by Washington University in St.Louis School of Medicine Dean’s Medical Student Research Fellowship for the MD5 Yearlong Research ProgramGetahun H is also a recipient of a Research to Prevent Blindness Medical Student Eye Research Fellowship.
文摘AIM:To evaluate visual outcomes of pars plana vitrectomy(PPV)combined with tissue plasminogen activator(tPA)-induced clot lysis and pneumatic displacement for submacular hemorrhage(SMH)in a cohort of closed-globe trauma patients.METHODS:A retrospective,multicenter interventional case series involving 7 eyes of 7 patients who underwent PPV with subretinal tPA administration for SMH secondary to closed-globe injury were conducted.The primary outcome measure was the change in Snellen visual acuity.RESULTS:The mean age of patients was 32y(range:21-51y),with a mean follow-up duration of 4.6mo(range:1.1-14.9mo).The average best-corrected visual acuity(BCVA)was 20/1020 at baseline and 20/114 at the final visit,respectively(P=0.025).Preoperative BCVA was not a significant predictor of final BCVA(r=0.102,P=0.827).Final BCVA did not differ significantly between patients who underwent PPV within 14d of symptom onset and those who underwent surgery after 14d(P=0.57).All eyes received SF6 or C3F8 gas tamponade.CONCLUSION:Surgical intervention involving tPAmediated clot lysis and pneumatic displacement may yield visual benefits in trauma-induced SMH without underlying retinal vascular disease;however,larger prospective studies are warranted to confirm these findings.
基金support from the Shenzhen Science and Technology Innovation Commission(Grant No.JCYJ20200109115439775 and JCYJ20230807140459034)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515012645)National Natural Science Foundation of China(Grant No.11872369).
文摘Four-dimensional(4D)printing represents a groundbreaking advancement in manufacturing,yet a persistent challenge is the limited number of stable configurations achievable through spontaneous shape reconstruction.Herein,we present a novel 4D printing mechanism that utilizes self-adjustable gas pressure to facilitate a wide range of spontaneous and stable multi-shape transformations.The gas is precisely released at designated spatial locations through strategic temperature-controlled degradation of a solid material,which is printed and distributed as needed at the voxel level within a specially designed multi-material structure,consisting of a low degradation temperature material(LDTM),a high degradation temperature soft material(HDTSM),and a high degradation temperature hard material(HDTHM).Each shape configuration is determined and locked in by the maximum temperature experienced during its thermal history.Notably,this shape retains its form robustly,independently of subsequent temperature changes,until a higher temperature threshold is reached,at which point a new shape configuration is triggered.These shapes exhibit a remarkable temperature memory effect,permanently recording the peak temperature reached in their thermal history.Our study comprehensively investigates the underlying principles and key parameters that influence deformation.We present a series of examples demonstrating complex multi-shape transformations modulated by temperature,supported by finite element simulations.This advance in 4D printing has the potential to significantly enhance its functional capabilities,performance,and applicability,opening up new horizons in additive manufacturing and design.
基金supported by Sichuan Provincial Department of Science and Technology Key Research and Development Program in High-Tech Fields(2022YFG0240).
文摘Pneumatic soft robots have undergone significant advancements in recent years.However,the majority of robot motion control still relies on electronic computers to regulate the valves and air pumps.Despite the potential reduction in controller dependency by utilizing soft pneumatic oscillators,challenges such as low flow rates,complex manufacturing processes,and lack of adjustment ability persist.Inspired by the geckos'spine,we propose a Spinal Bistable Oscillator(SBO)that operates without discrete components or electronic control hardware,achieving stable oscillatory motion under constant air pressure.This oscillator employs a soft control valve and lagging pin,which can switch the direction of airflow conduction based on the oscillation angle of the spine.Different types of actuators can be controlled using a series connection.In this study,the effective working range of the soft control valve,influence of the spring pretension force on the torque during oscillation,and effect of different throttle tube lengths on the oscillation frequency were investigated.Furthermore,a self-crawling robot was developed.Experimental results demonstrate that the robot can crawl at speeds ranging from 3.6 to 5.7 mm/s(or 3.1 to 4.9 body length/min)and overcome its own gravity(with a weight of 165 g)to climb vertically.The SBO proposed in this study exhibits characteristics of lightweight,low cost,high oscillation torque,and tunable frequency.It holds promise for application in joint control of future pneumatic soft robots.
基金supported by the Natural Science Foundation of Jilin Province(YDZJ202101ZYTS143).
文摘Pneumatic down-the-hole hammer, serving as rock-breaking tool, possesses appeal for directional drilling due to its high rate of penetration. However, corresponding experimental studies on existing hammers for directional drilling have rarely been reported, and a model for evaluating their output performance is absent. This study proposes a novel structure of self-rotating pneumatic hammer(NSH)with a built-in rotational mechanism, which converts partial impact energy of the piston to rotate the drill bit and, consequently, enables dual functions of impact and rotate drill bit. The energy is converted via a screw key-groove mechanism, and the wedge-shaped teeth mechanism ensures that the drill bit rotates clockwise during the piston moves downward. The computational fluid dynamics method is applied to simulate the dynamic response of airflow and piston during the operation of Φ127NSH.Meanwhile, a test bench is established to record data concerning chamber pressure and piston displacement, as well as recording its operational status and rock fragmentation during drilling into granite. The results showed that the maximum error between simulated and experimental data is 8.2%.The Φ127NSH successfully achieves dual impact and rotary drilling functions, and granite smoothly feeds and forms a continuous shear rock zone. In addition, the effects of torque load, engagement distance in rotation sleeves, and well deviation angle towards the performance of NSH were studied in detail. The designed Φ127NSH operates at an impact velocity of 3.98 m/s, impact frequency of 12.55 Hz, and rotational speed of 29.51 r/min under a mass-flow rate of 0.18 kg/s, torque load of 400 N·m, engagement distance of 40 mm, and well deviation angle of 0°. The torque load adversely affects the NSH output performance. Increasing the engagement distance improves impact performance while reducing rotational performance. The performance variation of the NSH is minimal when drilling directional wells with varying deviation angles.
基金Supported by Shenzhen Municipal Natural Science Foundation of China(Grant No.U2013212)National Key R&D Program of China(Grant No.2020YFB1313001)National Natural Science Foundation of China(Grant No.U23 A20328).
文摘Continuum robots have been a hot topic in recent years due to their intrinsic features of agility,flexibility,and safety.To successfully deploy continuum robots in practical applications,further enhancements in variable stiffness,decoupled motion,and embedded sensing are highly desirable.Since continuum robots are usually composed of multiple joints assembled in series,their mechanical properties and performance will certainly rely on the connected joints.This paper proposes a motion-decoupled variable stiffness-decoupled pneumatic rigid-flexible hybrid joint(RFHJ),which is modular designed and integrated with a rigid hinge,a stiffness-tuning module,and soft actuators.The soft pneumatic muscle actuators are pre-stretched during assembly,ensuring the stable initial state of RFHJ.A novel musculature-mounting configuration is also presented,which enables RFHJs to achieve independent motions in two orthogonal planes.Furthermore,the variable stiffness module is embedded in the RFHJ’s structure to offer real-time and independent stiffness tunability across multiple scales in two perpendicular directions.The proposed RFHJ makes most of the advantages of soft continuum robots and conventional rigid serial robots by introducing a hybrid structure to provide both safe human-robot interaction(HRI),accurate control and reliable stiffness variation,presenting promising potentials for robotic systems,which have been theoretically proved and experimentally verified on the physical prototype.The experimental results also indicate that the developed RFHJ can work with variable stiffness ranging in[1.2,49.9]N·m/rad.A variable stiffness rigid-flexible hybrid continuum arm(RFHA)is designed with three RFHJs in series.Primary tests on the developed RFHA prototype demonstrate that it has the characteristics of decoupled driving,bidirectional stiffness tunability and self-stability.
基金funding from Shanghai Sailing Program (22YF1417600)Guangxi Science and Technology Major Program (AA23062019)
文摘The complex dense-phase pneumatic conveying of pulverized coal process was studied using an electrical capacitance tomography(ECT) signal that represented the motion characteristics of gas-solid two-phase flow. The fluctuation characteristics of conveying process signals are inseparable from the flow pattern. The denoised ECT signal and noise signal were obtained by db2 wavelet analysis. It was found that all noise signals were white Gaussian noise. Based on the assumption of the equal probability distribution of pulverized coal concentration, this paper proved that the time series distribution of pulverized coal concentration in the pipeline should obey the normal distribution. Furthermore, through the analysis of the distribution characteristics of the power spectral density function of denoised ECT signals of four flow patterns, they were α-dimensional fractal Brownian motion(fBm) signals, and the parameter α was estimated by the detrended fluctuation analysis. Based on the fBm characteristics of denoised ECT signals and white Gaussian noise, this paper proposed a method for calculating the pulverized coal concentration in the dense-phase pneumatic conveying. In addition to the method of concentration estimation with the significance of engineering guidance, this research can help people to further understand essential characteristics of ECT signals in the dense-phase pneumatic conveying.
基金supported by the National Natural Science Foundation of China(No.52475067).
文摘Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using linear PAMs(LPAMs)designed to mimic human skeletal muscle.LPAMs have considerable potential for wearable applications and can be integrated into soft wearable robotic systems.Due to their inherent compliance,excellent human-robot interaction,safety,and low cost,LPAMs are considered potential alternatives as actuator components in the construction of wearable robots.This review presents a comprehensive overview of the bio-inspired design of LPAMs and their wearable applications.The biomechanics of human skeletal muscle,including anatomy,morphology,and biomechanical characterization,is analyzed to provide design inspirations for LPAMs and determine the assistance requirements of LPAM-based wearable robots.Herein,LPAMs are classified into four categories based on their structural shapes,including cylindrical-shaped muscles,flat-shaped muscles,fold-shaped muscles,and muscles with other shapes.In addition,this review provides an overview of the diverse physical interfaces utilized in wearable robots and presents a comparative analysis of the actuation characteristics of LPAMs and the assistance performance of LPAM-based wearable robots.This analysis was conducted in consideration of several key metrics,including the contraction ratio,maximum force,specific force,response frequency,assistive torque/bodyweight,and net metabolic cost.Finally,this review summarizes the ongoing challenges and future research directions.
基金supported by the[National Natural Science Foundation of China]under Grant[number 12172082][Catch up with and surpass technology projects]under Grant[number 2022LCJSGC24]。
文摘Background The middle ear pneumatic system(MEPS)supports pressure balance,essential for sound conduction.Its volume and surface area are key indicators of pneumatization and ventilation,yet their specific contributions to pressure regulation need further exploration.Objective To evaluate the accuracy and sensitivity of parameters characterizing the MEPS,including volume(V),surface area(S),and surface-area-to-volume ratio(S/V),in normal ears.Materials and Methods We collected CT images of the temporal bone from 63 normal ears for this study.The volume(V),surface area(S),and surface-area-to-volume ratio(S/V)of the MEPS were measured and calculated using three-dimensional reconstruction technology.Statistical methods were used to process the data and determine the 95%reference range for the S,V,and S/V of the MEPS in the normal ear.At the same time,we analyzed the impact of differences in gender and the left and right sides on the measurements.Results The 95%reference values for the S,V,and S/V of the MEPS in normal ears were 1057.10~18239.16 mm²,609.16~9854.11 mm^(3),and 1.39~2.52 mm^(-1) respectively.There were no significant differences in the measurements between genders and between the left and right sides.Conclusions and Significance This study has established the 95%reference values for the S,V,and S/V of the MEPS in normal ears,which were 1057.10-18239.16 mm²,609.16-9854.11 mm^(3),and 1.39-2.52 mm^(-1) respectively.We found that while there is a wide variation in the V values among normal ears,there is less variability in the S/V values.This structural characteristic suggests that changes in the S/V value may have a more significant impact on the balance of middle ear pressure,and it provides important reference data for the construction and functional reconstruction of three-dimensional models of the MEPS.These findings may aid in diagnosing middle ear disorders,such as otitis media with effusion,and guide interventions to restore pressure balance.
基金Supported by National Natural Science Foundation of China (Grant No.51875256)Open Platform Fund of Human Institute of Technology (Grant No.KFA22009)。
文摘Because of significantly changed load and complex and variable driving road conditions of commercial vehicles,pneumatic suspension with lower natural frequencies is widely used in commercial vehicle suspension system.How ever,traditional pneumatic suspension system is hardly to respond the greatly changed load of commercial vehicles To address this issue,a new Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension(GIQZSPS)is presented in this paper to improve the vibration isolation performance of commercial vehicle suspension systems under frequent load changes.This new structure adds negative stiffness air chambers on traditional pneumatic suspension to reduce the natural frequency of the suspension.It can adapt to different loads and road conditions by adjusting the solenoid valves between the negative stiffness air chambers.Firstly,a nonlinear mechanical model including the dimensionless stiffness characteristic and interconnected pipeline model is derived for GIQZSPS system.By the nonlinear mechanical model of GIQZSPS system,the force transmissibility rate is chosen as the evaluation index to analyze characteristics.Furthermore,a testing bench simulating 1/4 GIQZSPS system is designed,and the testing analysis of the model validation and isolating performance is carried out.The results show that compared to traditional pneumatic suspension,the GIQZSPS designed in the article has a lower natural frequency.And the system can achieve better vibration isolation performance under different load states by switching the solenoid valves between air chambers.
基金supported by the National Science and Technology Major Project(Grant Nos.2017-V-0016-0068,and J2019-V-0017-0112)the National Natural Science Foundation of China(Grant No.51776011).
文摘The pneumatic probe is widely used for contact measurements in turbomachinery flow field research.However,it inevitably interferes with the original flow field,leading to additional errors,particularly in wake flow fields or transonic regions with significant pressure gradients.This study employed Reynolds-Averaged Navier-Stokes delete and high-fidelity numerical simulation to investigate the impact of an inserted pneumatic probe on the wake flow field of a transonic turbine blade and compared it to the baseline flow field.Results indicate that the probe causes the shock waves premature occurrence in the high subsonic wake region near the turbine blade trailing edge.These shock waves affect vortex shedding by thickening the boundary layer near the trailing edge and changing the shedding pattern from high-frequency-low-energy to low-frequencyhigh-energy.In addition,the extra flow loss is incurred,and the blade's heat transfer characteristic is changed.This research provides a reference for testing experiments in complex transonic flow fields,guiding experimental researchers to minimize instrument interference with the original flow field.
文摘Pneumatic conveying technology,as an efficient material transportation method,has been widely used in various industrial fields.To study the powder transportation in horizontal ash conveying pipes,this study relies on the Computational Particle Fluid Dynamics(CPFD)numerical method.The characteristics of the gas-solid two-phase flow under continuous air supply conditions are analyzed,and the effects on particle movement of factors such as feed port spacing,inlet air velocity,and the number of discharge ports are explored accordingly.The research results show that when the inlet velocity is 5 m/s,adjacent discharged particles come into contact after 8 s.As the inlet air velocity increases,the contact time between adjacent discharge ports is shortened.When the feed port spacing increases from 0.5 to 2 m,the dust accumulation thickness decreases by about 0.6 times.Additionally,when the spacing reaches a certain value,the rate of decrease in dust accumulation thickness begins to diminish.
文摘●AIM:To evaluate the efficacy of pneumatic retinopexy(PR)in patients undergoing PR as primary treatment for rhegmatogenous retinal detachment(RRD)and analyze the factors associated with success and failure in the studied population.●METHODS:A retrospective chart review was done of patients with RRD treated with PR as primary management method treated at New York Eye and Ear Infirmary of Mount Sinai between January 2017 and December 2021.Primary outcome measured success or failure of PR.Secondary outcome measured best corrected visual acuity(BCVA)after PR.A separate risk analysis was done to identify and stratify risks associated with success and failure of PR.●RESULTS:A total of 179 eyes from 179 patients were included for final analysis.The 83 patients(46.37%)achieved anatomical reattachment of the retina after primary PR with no need for additional surgery.The 96 patients(53.63%)had a failed primary PR and required a PPV and 6 of them required pars plana vitrectomy(PPV)with scleral buckle(SB).In total,19 cases(10.61%)were done as temporizing pneumatics,18(94.74%)underwent PPV,and 1(5.26%)did not require further intervention.The visual acuities at postoperative month 1(POM1)for patients who underwent primary PR successfully and for those that underwent PPV after,were 0.58(20/80)and 1.03(20/200)respectively.Patients who met Pneumatic Retinopexy Versus Vitrectomy for the Management of Primary Rhegmatogenous Retinal Detachment Outcomes Randomized Trial(PIVOT)criteria had a statistically significant decreased risk of primary PR failing(hazard ratio 0.29,P=0.00).Majority of missed or new breaks were found superotemporally.●CONCLUSION:PR is a good treatment option for treating RRDs in patients that meet PIVOT criteria and can be conducted as a temporizing measure.PIVOT criteria and fovea on status decrease the risk of PR failure.
文摘Achalasia can significantly impair the quality of life.The clinical presentation typically includes dysphagia to both solids and liquids,chest pain,and regurgitation.Diagnosis can be delayed in patients with atypical presentations,and they might receive a wrong diagnosis,such as gastroesophageal reflux disease(GERD),owing to overlapping symptoms of both disorders.Although the cause of achalasia is poorly understood,its impact on the motility of the esophagus and gastroesophageal junction is well established.Several treatment modalities have been utilized,with the most common being surgical Heller myotomy with concomitant fundoplication and pneumatic balloon dilatation.Recently,peroral endoscopic myotomy(POEM)has gained popularity as an effective treatment for achalasia,despite a relatively high incidence of GERD occurring after treatment compared to other modalities.The magnitude of post-POEM GERD depends on its definition and is influenced by patient and procedure-related factors.The longterm sequelae of post-POEM GERD are yet to be determined,but it appears to have a benign course and is usually manageable with clinically available modalities.Identifying risk factors for post-POEM GERD and modifying the POEM procedure in selected patients may improve the overall success of this technique.
基金National Science and Technology Major Project of China No.2017-V-0012-0064。
文摘The accurate parameters measurement of the flow field between the stages for axial compressors is a significant demand.This paper proposes an axial compressor inter-stage flow field high-precision test system,which mainly consists of a probe motion scanning mechanism,fully automated test control software,and data processing methods.Iterative correction is applied to the original readings obtained from the scanning tests to enhance testing accuracy.Using this test system,detailed tests are conducted on a 1.5-stage subsonic axial compressor under different operating conditions.The test results effectively captured the impact of surface roughness and tip clearance variations on compressor performance.The distribution characteristics of parameters measured in inter-stage sections can characterize the effects of blade wake area and changes in aerodynamic performance at different blade heights.The developed test system can be extended to multi-stage compressors.
文摘Introduction: Mechanism of male androgenic alopecia (MAGA) is complex and leads to an excessive hair shedding and decreased hair density. Oral, topical, and injectable autologous treatments demonstrate ability to stimulate hair re-growth, but the response is suboptimal or plateaus off. Synthetic combination of the peptide complex and hyaluronic acid (P-HA) demonstrated hair regrowth in alopecia patients. Electronically-operated pneumatic injections (EPI) generate micro-trauma in the dermis and under wound-healing conditions may enhance regeneration effect of P-HA. Methods: Subjects seeking improvement of their male pattern hair loss (Hamilton-Norwood type 2-4) received the P-HA treatments through EPI. The course included 4 treatments every two weeks over the 8-week period. In 6 months, the hair growth was assessed comparative to baseline by global clinical photography and digital phototrichograms. The treatment safety and tolerability were documented through the whole study period. Results: Twelve men (30-45 years old) completed the treatment course with high tolerability and without adverse events. Post-treatment assessment of the previously bald areas showed improved coverage on the clinical photographs. The phototrichograms demonstrated statistically significant increase in terminal hair density by 36%, cumulative hair thickness by 37%, and follicular units by 20%;all contributing to a 38% increase in cumulated hair density (all p Conclusion: Electronic pneumatic injections are well tolerated and can be safely used for the needle-free administration of the peptide-hyaluronic acid combination in MAGA therapy. We achieved significant hair re-densification in the balding scalp. The exact role of the EPI-induced impact in the hair re-growth mechanism remains to be ascertained. .
文摘The analysis of the characteristics of the cushion process of the pneumatic cushion cylinder is presented, and the nonlinear model of pneumatic cushion cylinders is built in the form of nonlinear differential equations. Besides, through the simulation of the pressure in the cushion chamber, the characteristics of the pneumatic cushion cylinder are obtained, which helps to understand the performance of the pneumatic cushion cylinder and improve or design the better cushion structure.
