In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved cerami...In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.展开更多
The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step...The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.展开更多
In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this stu...In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this study,the consistency of printed electrodes was measured by using a confocal microscope and the pressure distribution detected by online pressure monitoring system was compared to investigate the relationship.The results demonstrated the relationship between printing pressure and the consistency of printed electrodes.As printing pressure increases,the ink layer at the corresponding position becomes thicker and that higher printing pressure enhances the consistency of the printed electrodes.The experiment confirms the feasibility of the online pressure monitoring system,which aids in predicting and controlling the consistency of printed electrodes,thereby improving their performance.展开更多
A study recently published in Scientific Reports shows that fibers from agricultural waste can make 3D-printed concrete stronger and more environmen-tally friendly.This approach not only gives new life to organic wast...A study recently published in Scientific Reports shows that fibers from agricultural waste can make 3D-printed concrete stronger and more environmen-tally friendly.This approach not only gives new life to organic waste but also helps address the environmental issues linked to traditional building materials.The research found that adding natural fibers improves both the strength and the printability of concrete,offering a more efficient and eco-friendly option for modern construction.展开更多
Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape,size and distribution of inorganic crystals,giving them unique structures and properties o...Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape,size and distribution of inorganic crystals,giving them unique structures and properties of biomaterials.These underlying mechanisms and pathways provide inspiration for the design and construction of materials for repairing hard tissues.Due to good biocompatibility of hydrogels,materials using gel-like systems as media are inextricably linked to biological macrocomponents and mineralization.Inspired by those bioprocesses,polyacrylamide hydrogel with enzymes was 3D printed to form controlled shapes and structures,then was used as templates for mineralization.Effect of polyacrylamide hydrogel pore size on the mineralization was studied via incorporating NaF and CaCl2 and controlling the mineralization degree.The mineralization processes of 3D printed hydrogels with different pore sizes were also explored to find out the confinement influence of pores.Mineralization in hydrogels with smaller pores is developed in a columnar stacked pattern,which is similar to the vesicular mineralization stage of bone mineralization.展开更多
3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have...3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion.展开更多
Wireless millirobots engineered to infiltrate intricate vascular networks within living organisms,particularly within constricted and confined spaces,hold immense promise for the future of medical treatments.However,w...Wireless millirobots engineered to infiltrate intricate vascular networks within living organisms,particularly within constricted and confined spaces,hold immense promise for the future of medical treatments.However,with their multifaceted and intricate designs,some robots often grapple with motion and functionality issues when confronted with tight spaces characterized by small cross-sectional dimensions.In this study,drawing inspiration from the high aspect ratio and undulating swimming patterns of snakes,a millimeter-scale,snake-like robot was designed and fabricated via a combination of extrusion-based four-dimensional(4D)printing and magnetic-responsive intelligent functional inks.A sophisticated motion control strategy was also developed,which enables the robots to perform various dynamic movements,such as undulating swimming,precise turns,graceful circular motions,and coordinated cluster movements,under diverse magnetic field variations.As a potential application,the snake robot can navigate and release drugs in a model coronary intervention vessel with tortuous channels and fluid filling.The novel design and promising applications of this snake robot are invaluable tools in future medical surgeries and interventions.展开更多
A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz abso...A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz absolute bandwidth and 142.7% relative bandwidth covering from 3.38 GHz to 20 GHz with voltage standing wave ratio （VSWR） below two. A quasi-omnidirectional and quasi-symmetrical radiation pattern in H plane is obtained in the whole bandwidth. The high performance of the antenna is validated with measured and simulated results given. The antenna can be applied for the system design of UWB wireless communication.展开更多
The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach...The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach—integrating biomedical engineering,advanced materials science,and emergency medicine expertise—to develop a compact,durable,and user-friendly ampoule case.A key innovation lies in the strategic selection of thermoplastic polyurethane(TPU)as the material,leveraging its superior impact resistance,flexibility,and noise-damping characteristics to ensure reliability under performance in demanding real-world conditions.To optimize the 3D printing process,key parameters,including printing temperature(220-250℃),volumetric flow rate(3-20 mm^(3)/s),retraction speed(30-90 mm/s),and retraction length(0.4-1.2 mm),were systematically adjusted using calibration models.The final optimized parameters(245℃,7 mm^(3)/s,90 mm/s,and 1.2 mm)reduced production time by 43%while preserving structural integrity.American Society for Testing and Materials(ASTM)international standard drop tests confirmed the case’s exceptional impact resistance,demonstrating a 90%reduction in ampoule breakage compared to polylactic acid plus.Further refinements,guided by feedback from 25 emergency professionals,resulted in medicationspecific color coding and an enhanced locking mechanism for usability in high-pressure situations.The final SafeAmpCase model withstood 18 consecutive drop trials without ampoule breakage,confirming its robustness in field conditions.This research underscores the transformative potential of additive manufacturing in developing customized,high-performance solutions for critical healthcare applications,setting a new benchmark for biomedical device design and rapid prototyping.展开更多
Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility,stretchability,and skin-like compliance.However,these sensors often have ...Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility,stretchability,and skin-like compliance.However,these sensors often have limited sensitivity and poor stability due to their bulk structure and strain concentration during stretching.In this study,we designed and fabricated diamond-,grid-,and peanut-shaped organohydrogel based on positive,near-zero,and negative Poisson’s ratios using digital light processing(DLP)-based 3D printing technology.Through structural design and optimization,the grid-shaped organohydrogel exhibited record sensitivity with gauge factors of 4.5(0–200%strain,ionic mode)and 13.5/1.5×10^(6)(0-2%/2%-100%strain,electronic mode),alongside full resistance recovery for enhanced stability.The 3D-printed grid structure enabled direct wearability and breathability,overcoming traditional sensor limitations.Integrated with a robotic hand system,this sensor demonstrated clinical potential through precise monitoring of paralyzed patients’grasping movements(with a minimum monitoring angle of 5°).This structural design paradigm advanced flexible electronics by synergizing high sensitivity,stability,wearability,and breathability for healthcare,and human-machine interfaces.展开更多
Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional(3D)structures conducive to tissue regeneration.Coiled fibrous scaffolds have emerg...Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional(3D)structures conducive to tissue regeneration.Coiled fibrous scaffolds have emerged as promising substrates owing to their ability to provide unique topographical cues.In this study,coiled poly(ε-caprolactone)(PCL)fibrous bundles were fabricated using an alginate-based composite system,and processed with 3D printing.The unique structure was obtained through the die-swell phenomenon related to the release of residual stresses from the printed strut,thereby transforming aligned PCL fibers into coiled structures.The effects of printing parameters,such as pneumatic pressure and nozzle moving speed,on fiber morphology were investigated to ensure a consistent formation of coiled PCL fibers.The resulting coiled PCL fibrous scaffold demonstrated higher activation of mechanotransduction signaling as well as upregulation of osteogenic-related genes in human adipose stem cells(hASCs),supporting its potential in bone tissue engineering.展开更多
The field of bone tissue engineering has experienced an increase in prevalence due to the inherent challenge of the natural regeneration of significant bone deformities.This investigation focused on the preparation of...The field of bone tissue engineering has experienced an increase in prevalence due to the inherent challenge of the natural regeneration of significant bone deformities.This investigation focused on the preparation of Three-Dimensional(3D)-printed Polycaprolactone(PCL)scaffolds with varying proportions of Nanohydroxyapatite(NHA)and Nanoclay(NC),and their physiochemical and biological properties were assessed.The mechanical properties of PCL are satisfactory;however,its hydrophobic nature and long-term degradation hinder its use in scaffold fabrication.NHA and NC have been employed to improve the hydrophilic characteristics,mechanical strength,adhesive properties,biocompatibility,biodegradability,and osteoconductive behavior of PCL.The morphology results demonstrated 3D-printed structures with interconnected rectangular macropores and proper nanoparticle distribution.The sample containing 70 wt%NC showed the highest porosity(65.98±2.54%),leading to an increased degradation rate.The compressive strength ranged from 10.65±1.90 to 84.93±9.93 MPa,which is directly proportional to the compressive strength of cancellous bone(2–12 MPa).The wettability,water uptake,and biodegradability of PCL scaffolds considerably improved as the amount of NC increased.The results of the cellular assays exhibited increased proliferation,viability,and adhesion of MG-63 cells due to the addition of NHA and NC to the scaffolds.Finally,according to the in vitro results,it can be concluded that 3D-printed samples with higher amounts of NC can be regarded as a suitable scaffold for expediting the regeneration process of bone defects.展开更多
Traditional linear vibration isolators struggle to combine high load-bearing capacity with low-frequency vibration isolation, whereas nonlinear metastructure isolators can effectively fulfill both functions. This pape...Traditional linear vibration isolators struggle to combine high load-bearing capacity with low-frequency vibration isolation, whereas nonlinear metastructure isolators can effectively fulfill both functions. This paper draws inspiration from the Quasi-Zero Stiffness (QZS) characteristics resulting from the buckling deformation of beams, and proposes a gear-based QZS structure by arranging beams in a circular array. We investigated the static mechanical behavior under different structural parameters, loading angles, and gear combinations through experiments and simulations, and demonstrated the mechanical performances could be effectively programmed. Subsequent vibration isolation tests on the double gears prove superior vibration isolation performance at low frequency while maintaining high load-bearing capacities. Additionally, a key contribution of our work is the development of a mathematical model to characterize the buckling behavior of the unit beam within the gear structure, with its accuracy validated through finite element analysis and experimental results. The gear’s modulus, number of teeth, and pressure angle are selected according to standard series, allowing the gear can be seamlessly integrated into existing mechanical systems in critical fields such as aerospace, military, and etc.展开更多
The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor...The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors.Here,a redox-active polymer poly(1,5-diaminonaphthalene)is developed and synthesized as an ultrafast,high-mass loading,and durable pseudocapacitive anode.The charge storage of poly(1,5-diaminonaphthalene)depends on the reversible coordination reaction of the C¼N group with Hþ,which enables fast kinetics associated with surface-controlled reactions.The 3D-printed organic electrode delivers a remarkable areal capacitance(8.43 F cm^(-2)at 30.78 mg cm^(-2))and thickness-independent rate per-formance.Furthermore,the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm^(-2)at-60℃,as well as operates well even at-80℃.This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.展开更多
Hypertrophic scars(HS)are fibrotic proliferative diseases that develop after deep skin injuries caused by trauma,burns,and surgery.Traditional treatment methods include both surgical and nonsurgical therapies.Early in...Hypertrophic scars(HS)are fibrotic proliferative diseases that develop after deep skin injuries caused by trauma,burns,and surgery.Traditional treatment methods include both surgical and nonsurgical therapies.Early intervention and combination therapy tailored to the individual needs of the patients are crucial for achieving optimal results.Three-dimensional(3D)printing technology,a rapid prototyping technique,is increasingly being applied in the medical field.The customization and precise functionality of 3D printing technology are particularly important for the rehabilitation of HS.This review provides an overview of HS and the role of 3D printing technology in medical applications,analyses the application of 3D-printed rehabilitation aids for HS,and discusses the use of 3D printing technology to improve HS treatment outcomes,thereby providing clinical guidance for effective HS rehabilitation.展开更多
Infections of Helicobacter pylori(H.pylori)affect 42.1%of Chinese and 43.1%of the world population.H.pylori inhabits the mucous sublayer at the pylorus,leading to gastric ulcers,gastritis,and even cancer.Oral antibiot...Infections of Helicobacter pylori(H.pylori)affect 42.1%of Chinese and 43.1%of the world population.H.pylori inhabits the mucous sublayer at the pylorus,leading to gastric ulcers,gastritis,and even cancer.Oral antibiotics are usually used to treat H.pylori infections,whereas traditional quadruple therapy has side effects including headaches,nausea,diarrhea,intestinal dysbacteriosis,antibiotic resistance,and repeat infections.Here,a drug-loaded magnetic microbullet was designed to realize long-term retention in the stomach for one-shot treatment for H.pylori infections.It comprises a hollow cylinder wherein eight microneedles homogenously distribute at the top and several round pores located at the bottom.Itwas three-dimensional(3D)-printed by stereolithography.A clarithromycin(CAM)ground mixture(CGM)was prepared to improve solubility.Enough CGM powders were filled into the cylinder,covered by a small round magnet,and sealed to form a CAM-loaded magnetic microbullet(CMMB).CAM continually released from CMMBs for>24 h.With outside magnetic guidance,an oral CMMB targeted the pylorus site and the microneedles immediately headed into the mucosa followed by long-term local drug release.The in vitro and in vivo safety of CMMBs was confirmed,where their swelling rates were low,and the oral CMMB was finally completely evacuated.An oral CMMB was administered to H.pylori-infected mice and maintained in the stomach for 36 h with magnetic guidance,and the successful eradication of H.pylori was confirmed after single-dose administration.Oral CMMBs are a convenient medication for the eradication of H.pylori.展开更多
In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heati...In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.展开更多
The integration of 3D-printed hydrogels in soft robotics enables the creation of flexible,adaptable,and biocompatible systems.Hydrogels,with their high-water content and responsiveness to stimuli,are suitable for actu...The integration of 3D-printed hydrogels in soft robotics enables the creation of flexible,adaptable,and biocompatible systems.Hydrogels,with their high-water content and responsiveness to stimuli,are suitable for actuators,sensors,and robotic systems that require safe interaction and precise manipulation.Unlike traditional techniques,3D printing offers enhanced capabilities in tailoring structural complexity,resolution,and integrated functionality,enabling the direct fabrication of hydrogel systems with programmed mechanical and functional properties.In this perspective,we explore the evolving role of 3D-printed hydrogels in soft robotics,covering their material composition,fabrication techniques,and diverse applications.We highlight advancements in hydrogel-based actuators,sensors,and robots,emphasizing their ability to perform intricate motions.In addition,we discuss challenges like mechanical robustness,scalability,and integration as well as the potential of hydrogels in soft robotics and explore future directions for their development.展开更多
Nacre exhibits exceptional mechanical properties,which are attributed to its brick-mortar microstructure with an integration of stiff mineral platelets and soft organic interfaces.The rapidly developing 3D printing te...Nacre exhibits exceptional mechanical properties,which are attributed to its brick-mortar microstructure with an integration of stiff mineral platelets and soft organic interfaces.The rapidly developing 3D printing technique has been used to make nacreinspired composites with similar brick-mortar structure.It is known that the strain hardening phenomenon plays an important role in the high strength and toughness of natural nacre.However,the role of strain hardening on the mechanical properties of biomimetic nacreous composites still lacks theoretical evaluation and experimental confirmation.Based on a mesomechanical theoretical model,we derive the stress-strain response and macroscopic strength of the brick-mortar structure under uniaxial tension.The brick-mortar structure shows three typical failure modes,according to the occurrence of strain hardening and platelet fracture.Furthermore,we investigate how the occurrence of strain hardening depends on its geometry and constituent properties.It is found that increasing the aspect ratio of the platelets promotes strain hardening,while increasing the stiffness of the soft phase leads to the disappearance of strain hardening.Furthermore,we utilize bi-material 3D printing technology to prepare biomimetic nacre samples and conduct uniaxial tensile mechanical tests.We observe the occurrence of strain hardening with the increase in the length of the platelets,resulting in a significant increase in the strength and fracture strain of artificial nacre.Our result highlights the significant role of strain hardening in regulating the mechanical properties of nacre-like composite materials.展开更多
4D printing technology represents a new generation of additive manufacturing methods that enable three-dimensional(3D)printed structures to change their shapes or properties over time(the fourth dimension)in response ...4D printing technology represents a new generation of additive manufacturing methods that enable three-dimensional(3D)printed structures to change their shapes or properties over time(the fourth dimension)in response to external stimuli such as temperature,magnetic fields,and light.Among the most popular types of 4D-printed structures are thermally responsive bilayer actuators using shape memory polymers,valued for their programmability and convenience.However,achieving precise deformations without collisions is hindered by the nonlinear and time-varying morphing process of these bilayer actuators,which is crucial for creating dynamically controllable shapes on demand in 4D printing.This study presents a rapid and effective design and optimization strategy for 4D printed self-folding structures that can be sequentially and accurately folded.Theoretical analyses were conducted to guide the design of the folding processes.The response surface method(RSM)was used to investigate key parameters affecting the design of 4D-printed bilayer actuators.The results indicate that increasing printing speed enhances internal strain,whereas higher printing temperatures,layer heights,or actuator heights have the opposite effect.The RSM model achieved an R-squared value of 0.983,accurately capturing the coupling effects of these variables on the output responses,thereby enabling controlled timescales for bending motion and sequential folding without collisions.These findings can be applied to enhance the design and acceleration of 4D-printed self-folding structures,ensuring controlled speed of shape transformation.To validate this concept,a self-folding hand-shaped structure with five fingers was designed and fabricated,demonstrating how design and printing parameters can precisely control the timescale of shape changes for each finger based on the design specifications.展开更多
基金National Natural Science Foundation of china(No.U2241205)the Natural Science Basic Research Program of Shaanxi(Nos.2022JC-33,2023-GHZD-35,and 2024JC-ZDXM-25)+1 种基金the Fundamental Research Funds for the Central Universitiesthe National 111 Project to provide fund for conducting experiments。
文摘In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.
基金supported by the National Natural Science Foundation of China(No.U21A2055),Natural Science Foundation of Tianjin of China(No.21JCQNJC01280)Tianjin Key R&D Program Beijing-Tianjin-Hebei Collaborative Innovation Project(No.22YFXTHZ00120).
文摘The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.
文摘In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this study,the consistency of printed electrodes was measured by using a confocal microscope and the pressure distribution detected by online pressure monitoring system was compared to investigate the relationship.The results demonstrated the relationship between printing pressure and the consistency of printed electrodes.As printing pressure increases,the ink layer at the corresponding position becomes thicker and that higher printing pressure enhances the consistency of the printed electrodes.The experiment confirms the feasibility of the online pressure monitoring system,which aids in predicting and controlling the consistency of printed electrodes,thereby improving their performance.
文摘A study recently published in Scientific Reports shows that fibers from agricultural waste can make 3D-printed concrete stronger and more environmen-tally friendly.This approach not only gives new life to organic waste but also helps address the environmental issues linked to traditional building materials.The research found that adding natural fibers improves both the strength and the printability of concrete,offering a more efficient and eco-friendly option for modern construction.
基金Funded by the Joint Fund of Natural Science Foundation of Hubei Province(No.2024AFD033)the Open Fund of Hubei Longzhong Laboratory。
文摘Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape,size and distribution of inorganic crystals,giving them unique structures and properties of biomaterials.These underlying mechanisms and pathways provide inspiration for the design and construction of materials for repairing hard tissues.Due to good biocompatibility of hydrogels,materials using gel-like systems as media are inextricably linked to biological macrocomponents and mineralization.Inspired by those bioprocesses,polyacrylamide hydrogel with enzymes was 3D printed to form controlled shapes and structures,then was used as templates for mineralization.Effect of polyacrylamide hydrogel pore size on the mineralization was studied via incorporating NaF and CaCl2 and controlling the mineralization degree.The mineralization processes of 3D printed hydrogels with different pore sizes were also explored to find out the confinement influence of pores.Mineralization in hydrogels with smaller pores is developed in a columnar stacked pattern,which is similar to the vesicular mineralization stage of bone mineralization.
基金funded by the National Natural Science Foundation of China(Grant No.06101213)the National Natural Science Foundation of China(Grant No.22105160).
文摘3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion.
基金the National Natural Science Foundation of China(Nos.52105421 and 52373050)the Guangdong Provincial Natural Science Foundation,China(No.2022A1515011621)+1 种基金the Science and Technology Projects in Guangzhou,China(Nos.202102080330 and 2024A04J6446)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.22qntd0101).
文摘Wireless millirobots engineered to infiltrate intricate vascular networks within living organisms,particularly within constricted and confined spaces,hold immense promise for the future of medical treatments.However,with their multifaceted and intricate designs,some robots often grapple with motion and functionality issues when confronted with tight spaces characterized by small cross-sectional dimensions.In this study,drawing inspiration from the high aspect ratio and undulating swimming patterns of snakes,a millimeter-scale,snake-like robot was designed and fabricated via a combination of extrusion-based four-dimensional(4D)printing and magnetic-responsive intelligent functional inks.A sophisticated motion control strategy was also developed,which enables the robots to perform various dynamic movements,such as undulating swimming,precise turns,graceful circular motions,and coordinated cluster movements,under diverse magnetic field variations.As a potential application,the snake robot can navigate and release drugs in a model coronary intervention vessel with tortuous channels and fluid filling.The novel design and promising applications of this snake robot are invaluable tools in future medical surgeries and interventions.
文摘A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz absolute bandwidth and 142.7% relative bandwidth covering from 3.38 GHz to 20 GHz with voltage standing wave ratio （VSWR） below two. A quasi-omnidirectional and quasi-symmetrical radiation pattern in H plane is obtained in the whole bandwidth. The high performance of the antenna is validated with measured and simulated results given. The antenna can be applied for the system design of UWB wireless communication.
基金Open access funding provided by Ben-Gurion University.
文摘The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach—integrating biomedical engineering,advanced materials science,and emergency medicine expertise—to develop a compact,durable,and user-friendly ampoule case.A key innovation lies in the strategic selection of thermoplastic polyurethane(TPU)as the material,leveraging its superior impact resistance,flexibility,and noise-damping characteristics to ensure reliability under performance in demanding real-world conditions.To optimize the 3D printing process,key parameters,including printing temperature(220-250℃),volumetric flow rate(3-20 mm^(3)/s),retraction speed(30-90 mm/s),and retraction length(0.4-1.2 mm),were systematically adjusted using calibration models.The final optimized parameters(245℃,7 mm^(3)/s,90 mm/s,and 1.2 mm)reduced production time by 43%while preserving structural integrity.American Society for Testing and Materials(ASTM)international standard drop tests confirmed the case’s exceptional impact resistance,demonstrating a 90%reduction in ampoule breakage compared to polylactic acid plus.Further refinements,guided by feedback from 25 emergency professionals,resulted in medicationspecific color coding and an enhanced locking mechanism for usability in high-pressure situations.The final SafeAmpCase model withstood 18 consecutive drop trials without ampoule breakage,confirming its robustness in field conditions.This research underscores the transformative potential of additive manufacturing in developing customized,high-performance solutions for critical healthcare applications,setting a new benchmark for biomedical device design and rapid prototyping.
基金financially supported by the National Key R&D Program of China (2022YFE0197100, 2023YFB4603500)Shenzhen Science and Technology Innovation Commission (KQTD20190929172505711)+1 种基金supported by MOE SUTD Kickstarter initiative (SKI2021_02_16)Singapore Ministry of Education academic research grant Tier 2 (MOE-T2EP50121-0007).
文摘Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility,stretchability,and skin-like compliance.However,these sensors often have limited sensitivity and poor stability due to their bulk structure and strain concentration during stretching.In this study,we designed and fabricated diamond-,grid-,and peanut-shaped organohydrogel based on positive,near-zero,and negative Poisson’s ratios using digital light processing(DLP)-based 3D printing technology.Through structural design and optimization,the grid-shaped organohydrogel exhibited record sensitivity with gauge factors of 4.5(0–200%strain,ionic mode)and 13.5/1.5×10^(6)(0-2%/2%-100%strain,electronic mode),alongside full resistance recovery for enhanced stability.The 3D-printed grid structure enabled direct wearability and breathability,overcoming traditional sensor limitations.Integrated with a robotic hand system,this sensor demonstrated clinical potential through precise monitoring of paralyzed patients’grasping movements(with a minimum monitoring angle of 5°).This structural design paradigm advanced flexible electronics by synergizing high sensitivity,stability,wearability,and breathability for healthcare,and human-machine interfaces.
基金supported by the‘Korea National Institute of Health’research project(2022ER130502)a grant from by SMC-SKKU Future Convergence Academic Research Program,2024supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2024-00336758)。
文摘Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional(3D)structures conducive to tissue regeneration.Coiled fibrous scaffolds have emerged as promising substrates owing to their ability to provide unique topographical cues.In this study,coiled poly(ε-caprolactone)(PCL)fibrous bundles were fabricated using an alginate-based composite system,and processed with 3D printing.The unique structure was obtained through the die-swell phenomenon related to the release of residual stresses from the printed strut,thereby transforming aligned PCL fibers into coiled structures.The effects of printing parameters,such as pneumatic pressure and nozzle moving speed,on fiber morphology were investigated to ensure a consistent formation of coiled PCL fibers.The resulting coiled PCL fibrous scaffold demonstrated higher activation of mechanotransduction signaling as well as upregulation of osteogenic-related genes in human adipose stem cells(hASCs),supporting its potential in bone tissue engineering.
文摘The field of bone tissue engineering has experienced an increase in prevalence due to the inherent challenge of the natural regeneration of significant bone deformities.This investigation focused on the preparation of Three-Dimensional(3D)-printed Polycaprolactone(PCL)scaffolds with varying proportions of Nanohydroxyapatite(NHA)and Nanoclay(NC),and their physiochemical and biological properties were assessed.The mechanical properties of PCL are satisfactory;however,its hydrophobic nature and long-term degradation hinder its use in scaffold fabrication.NHA and NC have been employed to improve the hydrophilic characteristics,mechanical strength,adhesive properties,biocompatibility,biodegradability,and osteoconductive behavior of PCL.The morphology results demonstrated 3D-printed structures with interconnected rectangular macropores and proper nanoparticle distribution.The sample containing 70 wt%NC showed the highest porosity(65.98±2.54%),leading to an increased degradation rate.The compressive strength ranged from 10.65±1.90 to 84.93±9.93 MPa,which is directly proportional to the compressive strength of cancellous bone(2–12 MPa).The wettability,water uptake,and biodegradability of PCL scaffolds considerably improved as the amount of NC increased.The results of the cellular assays exhibited increased proliferation,viability,and adhesion of MG-63 cells due to the addition of NHA and NC to the scaffolds.Finally,according to the in vitro results,it can be concluded that 3D-printed samples with higher amounts of NC can be regarded as a suitable scaffold for expediting the regeneration process of bone defects.
基金supported in part by National Key R&D Program of China under Grant 2024YFB4708600National Natural Science Foundation of China under Grant 52305304+3 种基金Jilin Youth Growth Technology Project under Grant 20230508147RCthe Science and Technology Research Project of Jilin Provincial Education Department(No.JJKH20231193KJ)supported in part by the National Natural Science Foundation of China under Grant 52021003 and Grant 52205565in part by the Natural Science Foundation of Jilin Province under Grant 20210101053JC.
文摘Traditional linear vibration isolators struggle to combine high load-bearing capacity with low-frequency vibration isolation, whereas nonlinear metastructure isolators can effectively fulfill both functions. This paper draws inspiration from the Quasi-Zero Stiffness (QZS) characteristics resulting from the buckling deformation of beams, and proposes a gear-based QZS structure by arranging beams in a circular array. We investigated the static mechanical behavior under different structural parameters, loading angles, and gear combinations through experiments and simulations, and demonstrated the mechanical performances could be effectively programmed. Subsequent vibration isolation tests on the double gears prove superior vibration isolation performance at low frequency while maintaining high load-bearing capacities. Additionally, a key contribution of our work is the development of a mathematical model to characterize the buckling behavior of the unit beam within the gear structure, with its accuracy validated through finite element analysis and experimental results. The gear’s modulus, number of teeth, and pressure angle are selected according to standard series, allowing the gear can be seamlessly integrated into existing mechanical systems in critical fields such as aerospace, military, and etc.
基金supported by National Natural Science Foundation of China(52072173)International Science and Technology cooperation program of Jiangsu Province(SBZ2022000084)Funding for Outstanding Doctoral Dissertation in NUAA(BCXJ23-10).
文摘The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors.Here,a redox-active polymer poly(1,5-diaminonaphthalene)is developed and synthesized as an ultrafast,high-mass loading,and durable pseudocapacitive anode.The charge storage of poly(1,5-diaminonaphthalene)depends on the reversible coordination reaction of the C¼N group with Hþ,which enables fast kinetics associated with surface-controlled reactions.The 3D-printed organic electrode delivers a remarkable areal capacitance(8.43 F cm^(-2)at 30.78 mg cm^(-2))and thickness-independent rate per-formance.Furthermore,the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm^(-2)at-60℃,as well as operates well even at-80℃.This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.
基金supported by the Cross-Disciplinary Research Fund Project of the Shanghai Ninth People’s Hospital of Shanghai Jiao Tong University School of Medicine(grant no.JYJC202236)the Shanghai Plastic Surgery Research Center of Shanghai Priority Research Center(grant no.2023ZZ02023)the Shanghai Healthcare System Key Supporting Disciplines Program(grant no.2023ZDFC0303).
文摘Hypertrophic scars(HS)are fibrotic proliferative diseases that develop after deep skin injuries caused by trauma,burns,and surgery.Traditional treatment methods include both surgical and nonsurgical therapies.Early intervention and combination therapy tailored to the individual needs of the patients are crucial for achieving optimal results.Three-dimensional(3D)printing technology,a rapid prototyping technique,is increasingly being applied in the medical field.The customization and precise functionality of 3D printing technology are particularly important for the rehabilitation of HS.This review provides an overview of HS and the role of 3D printing technology in medical applications,analyses the application of 3D-printed rehabilitation aids for HS,and discusses the use of 3D printing technology to improve HS treatment outcomes,thereby providing clinical guidance for effective HS rehabilitation.
基金supported by the National Natural Science Foundation of China(82073791).
文摘Infections of Helicobacter pylori(H.pylori)affect 42.1%of Chinese and 43.1%of the world population.H.pylori inhabits the mucous sublayer at the pylorus,leading to gastric ulcers,gastritis,and even cancer.Oral antibiotics are usually used to treat H.pylori infections,whereas traditional quadruple therapy has side effects including headaches,nausea,diarrhea,intestinal dysbacteriosis,antibiotic resistance,and repeat infections.Here,a drug-loaded magnetic microbullet was designed to realize long-term retention in the stomach for one-shot treatment for H.pylori infections.It comprises a hollow cylinder wherein eight microneedles homogenously distribute at the top and several round pores located at the bottom.Itwas three-dimensional(3D)-printed by stereolithography.A clarithromycin(CAM)ground mixture(CGM)was prepared to improve solubility.Enough CGM powders were filled into the cylinder,covered by a small round magnet,and sealed to form a CAM-loaded magnetic microbullet(CMMB).CAM continually released from CMMBs for>24 h.With outside magnetic guidance,an oral CMMB targeted the pylorus site and the microneedles immediately headed into the mucosa followed by long-term local drug release.The in vitro and in vivo safety of CMMBs was confirmed,where their swelling rates were low,and the oral CMMB was finally completely evacuated.An oral CMMB was administered to H.pylori-infected mice and maintained in the stomach for 36 h with magnetic guidance,and the successful eradication of H.pylori was confirmed after single-dose administration.Oral CMMBs are a convenient medication for the eradication of H.pylori.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.
基金supported by Singapore MOE Tier-2 Award MOE-T2EP50123-0015.
文摘The integration of 3D-printed hydrogels in soft robotics enables the creation of flexible,adaptable,and biocompatible systems.Hydrogels,with their high-water content and responsiveness to stimuli,are suitable for actuators,sensors,and robotic systems that require safe interaction and precise manipulation.Unlike traditional techniques,3D printing offers enhanced capabilities in tailoring structural complexity,resolution,and integrated functionality,enabling the direct fabrication of hydrogel systems with programmed mechanical and functional properties.In this perspective,we explore the evolving role of 3D-printed hydrogels in soft robotics,covering their material composition,fabrication techniques,and diverse applications.We highlight advancements in hydrogel-based actuators,sensors,and robots,emphasizing their ability to perform intricate motions.In addition,we discuss challenges like mechanical robustness,scalability,and integration as well as the potential of hydrogels in soft robotics and explore future directions for their development.
基金supported by the National Natural Science Foundation of China(Grant No.12372325).
文摘Nacre exhibits exceptional mechanical properties,which are attributed to its brick-mortar microstructure with an integration of stiff mineral platelets and soft organic interfaces.The rapidly developing 3D printing technique has been used to make nacreinspired composites with similar brick-mortar structure.It is known that the strain hardening phenomenon plays an important role in the high strength and toughness of natural nacre.However,the role of strain hardening on the mechanical properties of biomimetic nacreous composites still lacks theoretical evaluation and experimental confirmation.Based on a mesomechanical theoretical model,we derive the stress-strain response and macroscopic strength of the brick-mortar structure under uniaxial tension.The brick-mortar structure shows three typical failure modes,according to the occurrence of strain hardening and platelet fracture.Furthermore,we investigate how the occurrence of strain hardening depends on its geometry and constituent properties.It is found that increasing the aspect ratio of the platelets promotes strain hardening,while increasing the stiffness of the soft phase leads to the disappearance of strain hardening.Furthermore,we utilize bi-material 3D printing technology to prepare biomimetic nacre samples and conduct uniaxial tensile mechanical tests.We observe the occurrence of strain hardening with the increase in the length of the platelets,resulting in a significant increase in the strength and fracture strain of artificial nacre.Our result highlights the significant role of strain hardening in regulating the mechanical properties of nacre-like composite materials.
基金supported by National Natural Science Foundation of China(Grant No.52375272)Zhejiang Provincial Natural Science Foundation of China(Grant No.LR22E050006)China Postdoctoral Science Foundation(Grant Nos.2024M751644,2024M754069).
文摘4D printing technology represents a new generation of additive manufacturing methods that enable three-dimensional(3D)printed structures to change their shapes or properties over time(the fourth dimension)in response to external stimuli such as temperature,magnetic fields,and light.Among the most popular types of 4D-printed structures are thermally responsive bilayer actuators using shape memory polymers,valued for their programmability and convenience.However,achieving precise deformations without collisions is hindered by the nonlinear and time-varying morphing process of these bilayer actuators,which is crucial for creating dynamically controllable shapes on demand in 4D printing.This study presents a rapid and effective design and optimization strategy for 4D printed self-folding structures that can be sequentially and accurately folded.Theoretical analyses were conducted to guide the design of the folding processes.The response surface method(RSM)was used to investigate key parameters affecting the design of 4D-printed bilayer actuators.The results indicate that increasing printing speed enhances internal strain,whereas higher printing temperatures,layer heights,or actuator heights have the opposite effect.The RSM model achieved an R-squared value of 0.983,accurately capturing the coupling effects of these variables on the output responses,thereby enabling controlled timescales for bending motion and sequential folding without collisions.These findings can be applied to enhance the design and acceleration of 4D-printed self-folding structures,ensuring controlled speed of shape transformation.To validate this concept,a self-folding hand-shaped structure with five fingers was designed and fabricated,demonstrating how design and printing parameters can precisely control the timescale of shape changes for each finger based on the design specifications.
