Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted dru...Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted drug delivery.For implants,mechanical properties are key performance characteristics,so understanding the deformation and failure mechanisms is essential for selecting the appropriate implant structure.The deformation and fracture processes in PLA samples with different interior architectures have been studied through computer simulation and experimental research.Two TPMS topologies,the Schwarz Diamond and Gyroid architectures,were used for the sample construction by 3D printing.ANSYS software was utilized to simulate compressive deformation.It was found that under the same load,the vonMises stresses in the Gyroid structure are higher than those in the Schwartz Diamond structure,which was associated with the different orientations of the cells in the studied structures in relation to the direction of the loading axis.The deformation process occurs in the local regions of the studied TPMS structures.Maximum von Mises stresses were observed in the vertical parts of the structures oriented along the load direction.It was found that,unlike the Gyroid,the Schwartz Diamond structure contains a frame that forms unique stiffening ribs,which ensures the redistribution of the load under the vertical loading direction.An analysis of the mechanical characteristics of PLA samples with the Schwartz Diamond and Gyroid structures produced by the Fused Deposition Modeling(FDM)method was correlated with computer simulation.The Schwarz Diamond-type structure was shown to have a higher absorption energy than the Gyroid one.A study of the fracture in PLA samples with various cell sizes revealed a particular feature related to the samples’periodic surface topology and the 3D printing process.Scanning electron microscopic(SEM)studies of the samples deformed by compression showed thatwith an increase in the density of the samples,the failure mechanism changes from ductile to quasi-brittle due to the complex participation of both cell deformation and fiber deformation.展开更多
Integrating inorganic fillers into polymer-based 3D printing filaments is an effective strategy for improving thermal conduction but often compromises mechanical properties.In this study,we introduced electrospun poly...Integrating inorganic fillers into polymer-based 3D printing filaments is an effective strategy for improving thermal conduction but often compromises mechanical properties.In this study,we introduced electrospun polymer nanofibers(NF)into thermoplastic polyurethane(TPU)filaments alongside a ceramic filler,boron nitride(BN).By combining these organic(NF)and inorganic(BN)fillers,we created a dual-filler filament(TPU/BN/NF)that exhibited enhanced thermal conduction pathways without sacrificing the mechanical strength and electrical insulation.Comprehensive characterization demonstrated that BN improved heat transport,while a small fraction of electrospun NF effectively modulated the tensile modulus and partially recovered the strength lost upon BN addition.Finite element simulations further elucidated the influence of the nanofiber content,orientation,and length-to-diameter ratio on the mechanical performance.Notably,the dual-filler filaments retained good printability in standard fused deposition modeling(FDM)systems at optimized temperatures(about 210??℃).These findings offer a scalable approach for engineer multifunctional 3D printing filaments for 3D-printed thermal management products that require both thermal conduction performance and high insulation.展开更多
Electrochemical liquid lithium extraction technology has attracted much attention because of its high selectivity,good efficiency,and eco-friendliness.However,the low energy density per unit area and poor stability of...Electrochemical liquid lithium extraction technology has attracted much attention because of its high selectivity,good efficiency,and eco-friendliness.However,the low energy density per unit area and poor stability of traditional thin film electrodes(F-LMO),as well as manganese dissolution loss induced by the Jahn-Teller distortion of LiMn_(2)O_(4),hinder their industrial scalability.Herein,a durable and high-efficiency multistage porous LiMn_(2)O_(4) thick electrode was prepared sustainably by 3D printing technology(3DPLMO)for enhancing lithium recovery from salt lake brine.The multistage porous structure reduced the mass transfer resistance and shortened the ion diffusion path,which was conducive to accelerating the diffusion rate of Li+.Simultaneously,the three-dimensional conductive networks composed of reduced graphene oxide(r GO)and carbon nanotubes(CNT)synergized with the multistage pores effectively weakened the polarization phenomenon of the electrode and improved the stability of 3DP-LMO.The3DP-LMO exhibited a 5.5-fold higher extraction capacity per unit area and the Mn dissolution loss rate was only 1/15 compared with the F-LMO.Notably,the capacity retention rate of 3DP-LMO was 87.6%,significantly better than that of F-LMO(66.3%).Based on the quasi-in situ X-ray Diffraction results,the mechanism of lithium intercalation and deintercalation in 3DP-LMO was elucidated.Furthermore,lithium extraction parameters were optimized using response surface method-center composite design(RSM-CCD),resulting in an increase in lithium extraction capacity to 15.66 mg g^(-1)and a reduction in energy consumption to only 12.33 Wh mol^(-1).The results show that 3DP-LMO has significantly improved lithium extraction performance and stability,and has considerable prospects in practical application.展开更多
As bacterial infections have emerged as the second leading cause of death worldwide,the urgent demand for novel and effective antibacterial therapies continues to escalate.In this context,three-dimensional(3D)printing...As bacterial infections have emerged as the second leading cause of death worldwide,the urgent demand for novel and effective antibacterial therapies continues to escalate.In this context,three-dimensional(3D)printing technology offers transformative potential for the design and fabrication of oral formulations,internal implants,and external dressings in the management of bacterial inflammation.Conventional oral antibacterial agents often suffer from limitations in drug release kinetics and gastrointestinal stability.Leveraging 3D printing enables precise control over drug release profiles,thereby enhancing both bioavailability and therapeutic efficacy.Moreover,the development of internal implants requires high levels of individual specificity and structural precision.Through patient-specific customization and the incorporation of appropriate antibacterial materials,3D printing allows the fabrication of implants tailored to individual clinical needs,ultimately increasing surgical success rates and minimizing postoperative infection risks.Additionally,3D-printed external dressings exhibit excellent antibacterial activity,accelerate wound healing,and facilitate patient recovery.This review summarizes the fabrication methods,key advantages,and therapeutic outcomes of 3D printing in oral delivery systems,implantable devices,and wound dressings.It further highlights recent advances and emerging trends,offering insights and strategic guidance for the rational design and application of antibacterial therapeutics.展开更多
3D printing,as a versatile additive manufacturing technique,offers high design flexibility,rapid prototyping,minimal material waste,and the capability to fabricate complex,customized geometries.These attributes make i...3D printing,as a versatile additive manufacturing technique,offers high design flexibility,rapid prototyping,minimal material waste,and the capability to fabricate complex,customized geometries.These attributes make it particularly well-suited for low-temperature hydrogen electrochemical conversion devices—specifically,proton exchange membrane fuel cells,proton exchange membrane electrolyzer cells,anion exchange membrane electrolyzer cells,and alkaline electrolyzers—which demand finely structured components such as catalyst layers,gas diffusion layers,electrodes,porous transport layers,and bipolar plates.This review provides a focused and critical summary of the current progress in applying 3D printing technologies to these key components.It begins with a concise introduction to the principles and classifications of mainstream 3D printing methods relevant to the hydrogen energy sector and proceeds to analyze their specific applications and performance impacts across different device architectures.Finally,the review identifies existing technical challenges and outlines future research directions to accelerate the integration of 3D printing in nextgeneration low-temperature hydrogen energy systems.展开更多
Gradient refractive index(GRIN)metalenses are increasingly valued in high-frequency communication due to their exceptional radiation performance.Ceramics with high dielectric constants and low dielectric losses are id...Gradient refractive index(GRIN)metalenses are increasingly valued in high-frequency communication due to their exceptional radiation performance.Ceramics with high dielectric constants and low dielectric losses are ideal candidates for GRIN metalenses.Digital light processing(DLP)3D printing provides a feasible and efficient approach for manufacturing ceramic GRIN metalenses.However,the scattering of ultraviolet(UV)light by ceramic particles in the slurry reduces the printing accuracy of DLP technology,making it difficult to achieve the intricate structural features required for GRIN metalenses in high-frequency communication.In this work,we propose an approach to improve printing accuracy by optimizing the ceramic slurry composition and implementing a dimensional compensation design strategy.Utilizing geometric optics and the S-parameter inversion method,we design a GRIN metalens consisting of two distinct types of subwavelength unit cells(Y-shaped and circular hole geometries)with a minimum feature size of 160μm.Through a refined slurry formulation and precise design parameter compensation,high-fidelity ceramic GRIN metalenses are successfully fabricated.The fabricated metalens exhibits a maximum gain enhancement of 18.4 dBi and a deflection angle of±30°over a bandwidth of 37.84% in the W-band(75-110 GHz).The highly directional far-field beam radiation and efficient beam steering capabilities highlight the potential of ceramic GRIN metalenses for applications in satellite communications,radar systems,and other high-frequency technologies.展开更多
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
Internal structural defects in engineering rock masses vary in size,exhibit complex shapes,and are unevenly distributed.Dominant fractures within a rock mass often play a critical to its mechanical behavior,directly a...Internal structural defects in engineering rock masses vary in size,exhibit complex shapes,and are unevenly distributed.Dominant fractures within a rock mass often play a critical to its mechanical behavior,directly affecting the macromechanical properties and failure modes.These fractures affect the instability and failure of the surrounding rock,significantlyimpacting the overall stability of engineering structures.Herein,sand-powder three-dimensional(3D)printing technology was used to prepare rock-like specimens with internal fracture networks.Triaxial compression testing,post-failure fracture mapping,and fractal dimension analysis of the fracture surfaces were conducted to investigate the effects of dominant fracture angles on the strength and deformation of rocks with internal fracture networks under triaxial stress.The results indicate that the dominant fracture angle has a pronounced effect on the mechanical behavior of rock.With increasing angle,both compressive strength and elastic modulus exhibit an initial decline followed by an increase.Moreover,higher confiningpressure significantlyimproves the compressive strength of fractured rock.This enhancement weakens as the confiningpressure further increases.Moreover,with increasing confiningpressure,the differences between the maximum and minimum values of elastic moduli and lateral strain ratios in fractured rock gradually decrease.Thus,the impact of the dominant fracture angle on rock mass deformation decreases with increasing confiningpressure.This research elucidates the effects of dominant fracture angles on the mechanical and failure properties of complex fractured rock masses and the influenceof the confiningpressure on these relationships.It provides valuable theoretical insights and practical guidance for stability analyses in engineering rock masses.展开更多
This study presents and verifies a hybrid methodology for reliable determination of parameters in structural rheological models(Zener,Burgers,and Maxwell)describing the viscoelastic behavior of polyurethane specimens ...This study presents and verifies a hybrid methodology for reliable determination of parameters in structural rheological models(Zener,Burgers,and Maxwell)describing the viscoelastic behavior of polyurethane specimens manufactured using extrusion-based 3D printing.Through comprehensive testing,including cyclic compression at strain rates ranging from 0.12 to 120 mm/min(0%-15%strain)and creep/relaxation experiments(10%-30%strain),the lumped parameters were independently determined using both analytical and numerical solutions of the models’differential equations,followed by cross-verification in additional experiments.Numerical solutions for creep and relaxation problems were obtained using finite element analysis,with the three-parameter Mooney-Rivlin model and Prony series employed to simulate elastic and viscous stress components,respectively.Energy dissipation per cycle was quantified during cyclic compression tests.The results demonstrate that all three models adequately describe material behavior within the 0%-15%strain range across various strain rates.Comparative analysis revealed the Burgers model’s superior performance in characterizing creep and stress relaxation at low strain levels.While Zener and Burgers model parameters from uniaxial compression showed limited applicability for energy dissipation calculations,the generalized Maxwell model effectively captured viscoelastic properties across different strain rates.Notably,parameters derived from creep tests provided a more universal assessment of dissipative properties due to optimization based on characteristic curve regions.Both parameter sets described polyurethane’s elastic-hysteretic behavior with approximately 20%error,proving significantly more accurate than the linear strain-time dependence hypothesis.Finite element analysis(FEA)complemented numerical modeling by demonstrating that while the generalized Maxwell model effectively describes initial rapid stress-strain changes,FEA provides superior characterization of steady-state processes.This computational approach yields more physically representative results compared to simplified analytical solutions,despite certain limitations in transient analysis.展开更多
As surgical procedures transition from conventional resection to advanced tissue-regeneration technologies,human disease therapy has witnessed a great leap forward.In particular,three-dimensional(3D)bioprinting stands...As surgical procedures transition from conventional resection to advanced tissue-regeneration technologies,human disease therapy has witnessed a great leap forward.In particular,three-dimensional(3D)bioprinting stands as a landmark in this setting,by promising the precise integration of biomaterials,cells,and bioactive molecules,thus opening up a novel avenue for tissue/organ regeneration.Curated by the editorial board of Bio-Design and Manufacturing,this review brings together a cohort of leading young scientists in China to dissect the core functionalities and evolutionary trajectory of 3D bioprinting,by elucidating the intricate challenges encountered in the manufacturing of transplantable organs.We further delve into the translational pathway from scientific research to clinical application,emphasizing the imperativeness of establishing a regulatory framework and rigorously enforcing quality-control measures.Finally,this review outlines the strategic landscape and innovative achievements of China in this field and provides a comprehensive roadmap for researchers worldwide to propel this field collectively to even greater heights.展开更多
Ceramic matrix composites(CMCs)structural components encounter the dual challenges of severe mechanical conditions and complex electromagnetic environments due to the increasing demand for stealth technology in aerosp...Ceramic matrix composites(CMCs)structural components encounter the dual challenges of severe mechanical conditions and complex electromagnetic environments due to the increasing demand for stealth technology in aerospace field.To address various functional requirements,this study integrates a biomimetic strategy inspired by gradient bamboo vascular bundles with a novel dual-material 3D printing approach.Three distinct bamboo-inspired structural configurations Cf/SiC composites are designed and manufactured,and the effects of these different structural configurations on the CVI process are analyzed.Nanoindentation method is utilized to characterize the relationship between interface bonding strength and mechanical properties.The results reveal that the maximum flexural strength and fracture toughness reach 108.6±5.2 MPa and 16.45±1.52 MPa m1/2,respectively,attributed to the enhanced crack propagation resistance and path caused by the weak fiber-matrix interface.Furthermore,the bio-inspired configuration enhances the dielectric loss and conductivity loss,exhibiting a minimum reflection loss of−24.3 dB with the effective absorption band of 3.89 GHz.This work introduces an innovative biomimetic strategy and 3D printing method for continuous fiber-reinforced ceramic composites,expanding the application of 3D printing technology in the field of CMCs.展开更多
Electromagnetic devices have been widely used in the fields of information communication,medical treatment,electrical engineering,and national defense,and their properties are strongly dependent on the constituent ele...Electromagnetic devices have been widely used in the fields of information communication,medical treatment,electrical engineering,and national defense,and their properties are strongly dependent on the constituent electromagnetic materials.Conversely,electromagnetic metamaterials(EMMs),which are artificially engineered with distinctive electromagnetic properties,can overcome the limitations of natural materials owing to their structural advantages.Three-dimensional(3D)printing is the most effec-tive technique for fabricating EMM devices with different geometric parameters and associated proper-ties.However,conventional 3D-printed EMM devices may lack manufacturing flexibility and environmental adaptability to different physical stimuli,such as electric and magnetic fields.Four-dimensional(4D)printing is an ideal technique for schemes to integrate structural design with intelligent materials environmentally adaptive to external fields,for example,the printed components can change shape under electric stimulation.Given the rapid advancements in the EMM field,this paper first reviews typical EMM devices,their design theories,and underlying principles.Subsequently,it presents various EMM structural topologies and manufacturing technologies,emphasizing the feasibility of combining 3D and 4D printing.In addition,we highlight the important applications of EMMs and their future trends and the challenges associated with functional EMMs and additive manufacturing.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
As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires com...As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.展开更多
Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis.However,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and inflammation...Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis.However,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and inflammation.In this study,a composite bioink composed of methacrylated gelatin(GelMA)and chitosan oligosaccharide(COS)was proposed for printing a dermal scaffold using digital light processing(DLP)technology.The GelMA/COS bioink exhibited suitable porosity,swelling,degradation rate,and mechanical properties.The inclusion of COS demonstrated antibacterial effects against both Gram positive and Gram-negative bacteria,while simultaneously fostering the proliferation of human dermal fibroblasts(HDFs).Additionally,the application of COS could effectively reduce the expression levels of fibrosis-related genes,such as collagen I,collagen III,and fibronectin I.The three-dimensionally printed cell-laden dermal scaffold exhibited excellent shape fidelity and high cellular viability,facilitating the extension of HDFs along the scaffold and the simultaneous secretion of extracellular matrix proteins.Furthermore,the HDF-laden dermal scaffold transplanted into full-thickness skin defect sites in nude mice was shown to accelerate wound closure,reduce inflammation,and improve wound healing.Overall,the DLP-printed dermal scaffold provides an appealing approach for effectively treating full-thickness skin defects in clinical settings.展开更多
Ensuring the consistent mechanical performance of three-dimensional(3D)-printed continuous fiber-reinforced composites is a significant challenge in additive manufacturing.The current reliance on manual monitoring exa...Ensuring the consistent mechanical performance of three-dimensional(3D)-printed continuous fiber-reinforced composites is a significant challenge in additive manufacturing.The current reliance on manual monitoring exacerbates this challenge by rendering the process vulnerable to environmental changes and unexpected factors,resulting in defects and inconsistent product quality,particularly in unmanned long-term operations or printing in extreme environments.To address these issues,we developed a process monitoring and closed-loop feedback control strategy for the 3D printing process.Real-time printing image data were captured and analyzed using a well-trained neural network model,and a real-time control module-enabled closed-loop feedback control of the flow rate was developed.The neural network model,which was based on image processing and artificial intelligence,enabled the recognition of flow rate values with an accuracy of 94.70%.The experimental results showed significant improvements in both the surface performance and mechanical properties of printed composites,with three to six times improvement in tensile strength and elastic modulus,demonstrating the effectiveness of the strategy.This study provides a generalized process monitoring and feedback control method for the 3D printing of continuous fiber-reinforced composites,and offers a potential solution for remote online monitoring and closed-loop adjustment in unmanned or extreme space environments.展开更多
Integrating thick/thin film sensors into component systems has emerged as a prevalent approach for monitoring in extreme environments.However,traditional vapor deposition methods face obstacles,including complex fabri...Integrating thick/thin film sensors into component systems has emerged as a prevalent approach for monitoring in extreme environments.However,traditional vapor deposition methods face obstacles,including complex fabrication processes and the degradation of sensitive materials at extremely high temperatures.This work delineates the development of a polysilazane composite dual-layer thick-film Negative Temperature Coefficient(NTC)thermistor characterized by its suitability for extreme temperatures and robust bond strength achieved through an advanced near-net-shape printing methodology.High-temperature resistant La(Ca)CrO_(3)/polysilazane films were printed as the sensitive layer,while a dense layer formed by Cr_(2)O_(3)/polysilazane was used as the protective layer.The bilayer structure resulted in a 2.5-fold increase in adhesion strength compared to the single-layer La(Ca)CrO_(3)/polysilazane films.Experimental results indicate that the dual-layer thick-film NTC thermistor can be operated long-term at 1300℃ with a resistance drift rate of 0.9%/h and survive short-term exposure to temperatures up to 1550℃.As a proof of concept,this work applied 3D printing technology to fabricate a polysilazane composite dual-layer thick-film NTC thermistor on the surface of turbine blades and demonstrated its functionality under flame impingement at nearly 1300℃.Such flexible 3D printing techniques pave the way for a new paradigm in manufacturing sensors capable of withstanding ultra-high temperatures.展开更多
Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi...Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.展开更多
With the maturation of emerging information technologies(Internet of Things,cloud computing,and big data),distributed manufacturing has emerged as an important model for future manufacturing.3D printing,with its integ...With the maturation of emerging information technologies(Internet of Things,cloud computing,and big data),distributed manufacturing has emerged as an important model for future manufacturing.3D printing,with its integrated molding and design freedom,is a powerful catalyst for distributed manufacturing.This paper investigates the integrated production and transportation scheduling problem in distributed 3D printing.To solve this problem,we decompose the original problem into three sub-problems and design a multilevel optimization algorithm.We employ a genetic algorithm in the outer-level optimization to determine the optimal allocation of parts to machines.In the inner-level optimization,we utilize a simulated annealing algorithm to tackle the vehicle routing problem during the transportation stage followed by a local search algorithm to address the scheduling problem encountered during the production stage.Our algorithm is validated using real data from a 3D printing company,and the results show that our algorithm can obtain solutions that are the same as or better than those of Gurobi in a reasonable time for small-sized instances.Additionally,three types of initial methods are tested on large-sized instances to verify the efficiency of the proposed algorithm,and some interesting insights are also revealed and discussed.展开更多
Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat.However,the presence of resin vats limits the printing of multiscale multimaterial structures.In t...Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat.However,the presence of resin vats limits the printing of multiscale multimaterial structures.In this context,a novel 3D printing process is presented in which a cured structure is produced from acoustically levitated droplets without a physical vat.This enables the printing process to achieve high flexibility in the printing orientation and material supply.In pursuit of the envisioned 3D acoustic levitation printing strategy,acoustic levitation technology was utilized to suspend a photosensitive resin.Objects with small features were successfully produced by projecting patterns onto levitated resin droplets.Transforming printing orientations allows the fabrication of multiscale structures.Levitating resin droplets on-demand enables the rapid replacement of materials,thereby realizing effortless multimaterial 3D printing.By exploiting the flexibility of printing on levitation resin droplets,the capability of 3D printing on existing objects was established.Finally,an interesting example was illustrated,in which an object integrating liquid,gas,and solid materials was fabricated using the proposed 3D printing strategy.The results show that 3D printing on levitated droplets is feasible for fabricating multiscale and multimaterial objects,which contributes to the development of new 3D printing methods and potential applications.展开更多
文摘Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted drug delivery.For implants,mechanical properties are key performance characteristics,so understanding the deformation and failure mechanisms is essential for selecting the appropriate implant structure.The deformation and fracture processes in PLA samples with different interior architectures have been studied through computer simulation and experimental research.Two TPMS topologies,the Schwarz Diamond and Gyroid architectures,were used for the sample construction by 3D printing.ANSYS software was utilized to simulate compressive deformation.It was found that under the same load,the vonMises stresses in the Gyroid structure are higher than those in the Schwartz Diamond structure,which was associated with the different orientations of the cells in the studied structures in relation to the direction of the loading axis.The deformation process occurs in the local regions of the studied TPMS structures.Maximum von Mises stresses were observed in the vertical parts of the structures oriented along the load direction.It was found that,unlike the Gyroid,the Schwartz Diamond structure contains a frame that forms unique stiffening ribs,which ensures the redistribution of the load under the vertical loading direction.An analysis of the mechanical characteristics of PLA samples with the Schwartz Diamond and Gyroid structures produced by the Fused Deposition Modeling(FDM)method was correlated with computer simulation.The Schwarz Diamond-type structure was shown to have a higher absorption energy than the Gyroid one.A study of the fracture in PLA samples with various cell sizes revealed a particular feature related to the samples’periodic surface topology and the 3D printing process.Scanning electron microscopic(SEM)studies of the samples deformed by compression showed thatwith an increase in the density of the samples,the failure mechanism changes from ductile to quasi-brittle due to the complex participation of both cell deformation and fiber deformation.
基金supported by the National Natural Science Foundation of China(Nos.52575343 and 52175026)the Young Elite Scientists Sponsorship Program by CAST+2 种基金the Peiyang Startup FoundationFunding of Key Laboratory of Mechanism Theory and Equipment Design of the Ministry of EducationBasic Research Program of Coordinated Development of the Beijing Tianjin-Hebei Region(No.E2024202287)。
文摘Integrating inorganic fillers into polymer-based 3D printing filaments is an effective strategy for improving thermal conduction but often compromises mechanical properties.In this study,we introduced electrospun polymer nanofibers(NF)into thermoplastic polyurethane(TPU)filaments alongside a ceramic filler,boron nitride(BN).By combining these organic(NF)and inorganic(BN)fillers,we created a dual-filler filament(TPU/BN/NF)that exhibited enhanced thermal conduction pathways without sacrificing the mechanical strength and electrical insulation.Comprehensive characterization demonstrated that BN improved heat transport,while a small fraction of electrospun NF effectively modulated the tensile modulus and partially recovered the strength lost upon BN addition.Finite element simulations further elucidated the influence of the nanofiber content,orientation,and length-to-diameter ratio on the mechanical performance.Notably,the dual-filler filaments retained good printability in standard fused deposition modeling(FDM)systems at optimized temperatures(about 210??℃).These findings offer a scalable approach for engineer multifunctional 3D printing filaments for 3D-printed thermal management products that require both thermal conduction performance and high insulation.
基金supported by the National Key R&D Program of China(No.2022YFE0208300)the National Natural Science Foundation of China(No.22278426)+2 种基金the China National Funds for Distinguished Young Scientists(No.22425808)the China Postdoctoral Science Foundation(No.2025M771155)the Science Foundation of China University of Petroleum,Beijing(Nos.2462024XKBH001,2462022YJRC003,2462022YJRC002,2462025BJRC002)。
文摘Electrochemical liquid lithium extraction technology has attracted much attention because of its high selectivity,good efficiency,and eco-friendliness.However,the low energy density per unit area and poor stability of traditional thin film electrodes(F-LMO),as well as manganese dissolution loss induced by the Jahn-Teller distortion of LiMn_(2)O_(4),hinder their industrial scalability.Herein,a durable and high-efficiency multistage porous LiMn_(2)O_(4) thick electrode was prepared sustainably by 3D printing technology(3DPLMO)for enhancing lithium recovery from salt lake brine.The multistage porous structure reduced the mass transfer resistance and shortened the ion diffusion path,which was conducive to accelerating the diffusion rate of Li+.Simultaneously,the three-dimensional conductive networks composed of reduced graphene oxide(r GO)and carbon nanotubes(CNT)synergized with the multistage pores effectively weakened the polarization phenomenon of the electrode and improved the stability of 3DP-LMO.The3DP-LMO exhibited a 5.5-fold higher extraction capacity per unit area and the Mn dissolution loss rate was only 1/15 compared with the F-LMO.Notably,the capacity retention rate of 3DP-LMO was 87.6%,significantly better than that of F-LMO(66.3%).Based on the quasi-in situ X-ray Diffraction results,the mechanism of lithium intercalation and deintercalation in 3DP-LMO was elucidated.Furthermore,lithium extraction parameters were optimized using response surface method-center composite design(RSM-CCD),resulting in an increase in lithium extraction capacity to 15.66 mg g^(-1)and a reduction in energy consumption to only 12.33 Wh mol^(-1).The results show that 3DP-LMO has significantly improved lithium extraction performance and stability,and has considerable prospects in practical application.
基金National Key Research and Development Program Project of China(Grant No.2024YFC3506900)Tianjin Science and Technology Plan Project(Grant No.24JCYBJC00230)Party Building Innovation Research Project of Tianjin University of Traditional Chinese Medicine(Grant No.2024DJ03)。
文摘As bacterial infections have emerged as the second leading cause of death worldwide,the urgent demand for novel and effective antibacterial therapies continues to escalate.In this context,three-dimensional(3D)printing technology offers transformative potential for the design and fabrication of oral formulations,internal implants,and external dressings in the management of bacterial inflammation.Conventional oral antibacterial agents often suffer from limitations in drug release kinetics and gastrointestinal stability.Leveraging 3D printing enables precise control over drug release profiles,thereby enhancing both bioavailability and therapeutic efficacy.Moreover,the development of internal implants requires high levels of individual specificity and structural precision.Through patient-specific customization and the incorporation of appropriate antibacterial materials,3D printing allows the fabrication of implants tailored to individual clinical needs,ultimately increasing surgical success rates and minimizing postoperative infection risks.Additionally,3D-printed external dressings exhibit excellent antibacterial activity,accelerate wound healing,and facilitate patient recovery.This review summarizes the fabrication methods,key advantages,and therapeutic outcomes of 3D printing in oral delivery systems,implantable devices,and wound dressings.It further highlights recent advances and emerging trends,offering insights and strategic guidance for the rational design and application of antibacterial therapeutics.
基金the support from the National Natural Science Foundation of China(Nos.22208376,UA22A20429)the Qingdao New Energy Shandong Laboratory Open Project(QNESL OP 202303)+3 种基金Shandong Provincial Natural Science Foundation(Nos.ZR2024QB175,ZR2023LFG005)Fundamental Research Funds for the Central Universities(No.25CX07002A)National Natural Science Foundation of China(Z202401390008)The Hunan Provincial Natural Science Foundation(2025JJ60301)。
文摘3D printing,as a versatile additive manufacturing technique,offers high design flexibility,rapid prototyping,minimal material waste,and the capability to fabricate complex,customized geometries.These attributes make it particularly well-suited for low-temperature hydrogen electrochemical conversion devices—specifically,proton exchange membrane fuel cells,proton exchange membrane electrolyzer cells,anion exchange membrane electrolyzer cells,and alkaline electrolyzers—which demand finely structured components such as catalyst layers,gas diffusion layers,electrodes,porous transport layers,and bipolar plates.This review provides a focused and critical summary of the current progress in applying 3D printing technologies to these key components.It begins with a concise introduction to the principles and classifications of mainstream 3D printing methods relevant to the hydrogen energy sector and proceeds to analyze their specific applications and performance impacts across different device architectures.Finally,the review identifies existing technical challenges and outlines future research directions to accelerate the integration of 3D printing in nextgeneration low-temperature hydrogen energy systems.
基金financial support by the National Key Research and Development Program of China(No.2023YFB4605400)the National Natural Science Foundation of China(No.12472152)the Department of Science and Technology of Guangdong Province(No.2019QN01Z438)。
文摘Gradient refractive index(GRIN)metalenses are increasingly valued in high-frequency communication due to their exceptional radiation performance.Ceramics with high dielectric constants and low dielectric losses are ideal candidates for GRIN metalenses.Digital light processing(DLP)3D printing provides a feasible and efficient approach for manufacturing ceramic GRIN metalenses.However,the scattering of ultraviolet(UV)light by ceramic particles in the slurry reduces the printing accuracy of DLP technology,making it difficult to achieve the intricate structural features required for GRIN metalenses in high-frequency communication.In this work,we propose an approach to improve printing accuracy by optimizing the ceramic slurry composition and implementing a dimensional compensation design strategy.Utilizing geometric optics and the S-parameter inversion method,we design a GRIN metalens consisting of two distinct types of subwavelength unit cells(Y-shaped and circular hole geometries)with a minimum feature size of 160μm.Through a refined slurry formulation and precise design parameter compensation,high-fidelity ceramic GRIN metalenses are successfully fabricated.The fabricated metalens exhibits a maximum gain enhancement of 18.4 dBi and a deflection angle of±30°over a bandwidth of 37.84% in the W-band(75-110 GHz).The highly directional far-field beam radiation and efficient beam steering capabilities highlight the potential of ceramic GRIN metalenses for applications in satellite communications,radar systems,and other high-frequency technologies.
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 Key Research and Development Program Young Scientist Project(Grant No.2024YFC2911000)the National Natural Science Foundation of China(Grant No.52474103)the Major Basic Research Project of the Natural Science Foundation of Shandong Province(Grant No.ZR2024ZD22).
文摘Internal structural defects in engineering rock masses vary in size,exhibit complex shapes,and are unevenly distributed.Dominant fractures within a rock mass often play a critical to its mechanical behavior,directly affecting the macromechanical properties and failure modes.These fractures affect the instability and failure of the surrounding rock,significantlyimpacting the overall stability of engineering structures.Herein,sand-powder three-dimensional(3D)printing technology was used to prepare rock-like specimens with internal fracture networks.Triaxial compression testing,post-failure fracture mapping,and fractal dimension analysis of the fracture surfaces were conducted to investigate the effects of dominant fracture angles on the strength and deformation of rocks with internal fracture networks under triaxial stress.The results indicate that the dominant fracture angle has a pronounced effect on the mechanical behavior of rock.With increasing angle,both compressive strength and elastic modulus exhibit an initial decline followed by an increase.Moreover,higher confiningpressure significantlyimproves the compressive strength of fractured rock.This enhancement weakens as the confiningpressure further increases.Moreover,with increasing confiningpressure,the differences between the maximum and minimum values of elastic moduli and lateral strain ratios in fractured rock gradually decrease.Thus,the impact of the dominant fracture angle on rock mass deformation decreases with increasing confiningpressure.This research elucidates the effects of dominant fracture angles on the mechanical and failure properties of complex fractured rock masses and the influenceof the confiningpressure on these relationships.It provides valuable theoretical insights and practical guidance for stability analyses in engineering rock masses.
文摘This study presents and verifies a hybrid methodology for reliable determination of parameters in structural rheological models(Zener,Burgers,and Maxwell)describing the viscoelastic behavior of polyurethane specimens manufactured using extrusion-based 3D printing.Through comprehensive testing,including cyclic compression at strain rates ranging from 0.12 to 120 mm/min(0%-15%strain)and creep/relaxation experiments(10%-30%strain),the lumped parameters were independently determined using both analytical and numerical solutions of the models’differential equations,followed by cross-verification in additional experiments.Numerical solutions for creep and relaxation problems were obtained using finite element analysis,with the three-parameter Mooney-Rivlin model and Prony series employed to simulate elastic and viscous stress components,respectively.Energy dissipation per cycle was quantified during cyclic compression tests.The results demonstrate that all three models adequately describe material behavior within the 0%-15%strain range across various strain rates.Comparative analysis revealed the Burgers model’s superior performance in characterizing creep and stress relaxation at low strain levels.While Zener and Burgers model parameters from uniaxial compression showed limited applicability for energy dissipation calculations,the generalized Maxwell model effectively captured viscoelastic properties across different strain rates.Notably,parameters derived from creep tests provided a more universal assessment of dissipative properties due to optimization based on characteristic curve regions.Both parameter sets described polyurethane’s elastic-hysteretic behavior with approximately 20%error,proving significantly more accurate than the linear strain-time dependence hypothesis.Finite element analysis(FEA)complemented numerical modeling by demonstrating that while the generalized Maxwell model effectively describes initial rapid stress-strain changes,FEA provides superior characterization of steady-state processes.This computational approach yields more physically representative results compared to simplified analytical solutions,despite certain limitations in transient analysis.
基金supported by the National Natural Science Foundation of China(Nos.52325504,52235007,and T2121004).
文摘As surgical procedures transition from conventional resection to advanced tissue-regeneration technologies,human disease therapy has witnessed a great leap forward.In particular,three-dimensional(3D)bioprinting stands as a landmark in this setting,by promising the precise integration of biomaterials,cells,and bioactive molecules,thus opening up a novel avenue for tissue/organ regeneration.Curated by the editorial board of Bio-Design and Manufacturing,this review brings together a cohort of leading young scientists in China to dissect the core functionalities and evolutionary trajectory of 3D bioprinting,by elucidating the intricate challenges encountered in the manufacturing of transplantable organs.We further delve into the translational pathway from scientific research to clinical application,emphasizing the imperativeness of establishing a regulatory framework and rigorously enforcing quality-control measures.Finally,this review outlines the strategic landscape and innovative achievements of China in this field and provides a comprehensive roadmap for researchers worldwide to propel this field collectively to even greater heights.
基金supported by The National Key Research and Development Program of China(No.2019YFB1901001).
文摘Ceramic matrix composites(CMCs)structural components encounter the dual challenges of severe mechanical conditions and complex electromagnetic environments due to the increasing demand for stealth technology in aerospace field.To address various functional requirements,this study integrates a biomimetic strategy inspired by gradient bamboo vascular bundles with a novel dual-material 3D printing approach.Three distinct bamboo-inspired structural configurations Cf/SiC composites are designed and manufactured,and the effects of these different structural configurations on the CVI process are analyzed.Nanoindentation method is utilized to characterize the relationship between interface bonding strength and mechanical properties.The results reveal that the maximum flexural strength and fracture toughness reach 108.6±5.2 MPa and 16.45±1.52 MPa m1/2,respectively,attributed to the enhanced crack propagation resistance and path caused by the weak fiber-matrix interface.Furthermore,the bio-inspired configuration enhances the dielectric loss and conductivity loss,exhibiting a minimum reflection loss of−24.3 dB with the effective absorption band of 3.89 GHz.This work introduces an innovative biomimetic strategy and 3D printing method for continuous fiber-reinforced ceramic composites,expanding the application of 3D printing technology in the field of CMCs.
基金sponsored by the National Natural Science Foundation of China(52275331 and 52205358)the National Key Research and Development Program of China(2023YFB4604800)+1 种基金the Key Research and Development Program of Hubei Province(2022BAA011)the Hong Kong Scholars Program(XJ2022014).
文摘Electromagnetic devices have been widely used in the fields of information communication,medical treatment,electrical engineering,and national defense,and their properties are strongly dependent on the constituent electromagnetic materials.Conversely,electromagnetic metamaterials(EMMs),which are artificially engineered with distinctive electromagnetic properties,can overcome the limitations of natural materials owing to their structural advantages.Three-dimensional(3D)printing is the most effec-tive technique for fabricating EMM devices with different geometric parameters and associated proper-ties.However,conventional 3D-printed EMM devices may lack manufacturing flexibility and environmental adaptability to different physical stimuli,such as electric and magnetic fields.Four-dimensional(4D)printing is an ideal technique for schemes to integrate structural design with intelligent materials environmentally adaptive to external fields,for example,the printed components can change shape under electric stimulation.Given the rapid advancements in the EMM field,this paper first reviews typical EMM devices,their design theories,and underlying principles.Subsequently,it presents various EMM structural topologies and manufacturing technologies,emphasizing the feasibility of combining 3D and 4D printing.In addition,we highlight the important applications of EMMs and their future trends and the challenges associated with functional EMMs and additive manufacturing.
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support from the National Key Research and Development Program of China(No.2021YFB3701503)the Key Research and Development Program of Ningbo,China(No.2023Z107).
文摘As a novel 2D material,Ti_(3)C_(2)T_(x)-MXene has become a major area of interest in the field of microwave absorption(MA).However,the MA effect of common Ti_(3)C_(2)T_(x)-MXene is not prominent and often requires complex processes or combinations of other ma-terials to achieve enhanced performance.In this context,a kind of gradient woodpile structure using common Ti_(3)C_(2)T_(x)-MXene as MA ma-terial was designed and manufactured through direct ink writing(DIW)3D printing.The minimum reflection loss(RL_(min))of the Ti_(3)C_(2)T_(x)-MXene-based gradient woodpile structures with a thickness of less than 3 mm can reach-70 dB,showing considerable improve-ment compared with that of a completely filled structure.In addition,the effective absorption bandwidth(EAB)reaches 7.73 GHz.This study demonstrates that a Ti_(3)C_(2)T_(x)-MXene material with excellent MA performance and tunable frequency band can be successfully fab-ricated with a macroscopic structural design and through DIW 3D printing without complex material hybridization and modification,of-fering broad application prospects by reducing electromagnetic wave radiation and interference.
基金supported by the National Natural Science Foundation of China(Nos.51975400 and 62031022)the Shanxi Provincial Key Medical Scientific Research Project(No.2020XM06)+2 种基金the Shanxi Provincial Basic Research Project(Nos.202103021221006,20210302123040,and 202103021223069)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2021L044)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SX-TD026).
文摘Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis.However,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and inflammation.In this study,a composite bioink composed of methacrylated gelatin(GelMA)and chitosan oligosaccharide(COS)was proposed for printing a dermal scaffold using digital light processing(DLP)technology.The GelMA/COS bioink exhibited suitable porosity,swelling,degradation rate,and mechanical properties.The inclusion of COS demonstrated antibacterial effects against both Gram positive and Gram-negative bacteria,while simultaneously fostering the proliferation of human dermal fibroblasts(HDFs).Additionally,the application of COS could effectively reduce the expression levels of fibrosis-related genes,such as collagen I,collagen III,and fibronectin I.The three-dimensionally printed cell-laden dermal scaffold exhibited excellent shape fidelity and high cellular viability,facilitating the extension of HDFs along the scaffold and the simultaneous secretion of extracellular matrix proteins.Furthermore,the HDF-laden dermal scaffold transplanted into full-thickness skin defect sites in nude mice was shown to accelerate wound closure,reduce inflammation,and improve wound healing.Overall,the DLP-printed dermal scaffold provides an appealing approach for effectively treating full-thickness skin defects in clinical settings.
基金supported by National Key Research and Development Program of China(Grant No.2023YFB4604100)National Key Research and Development Program of China(Grant No.2022YFB3806104)+4 种基金Key Research and Development Program in Shaanxi Province(Grant No.2021LLRH-08-17)Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)K C Wong Education Foundation of ChinaYouth Innovation Team of Shaanxi Universities of ChinaKey Research and Development Program of Shaanxi Province(Grant 2021LLRH-08-3.1).
文摘Ensuring the consistent mechanical performance of three-dimensional(3D)-printed continuous fiber-reinforced composites is a significant challenge in additive manufacturing.The current reliance on manual monitoring exacerbates this challenge by rendering the process vulnerable to environmental changes and unexpected factors,resulting in defects and inconsistent product quality,particularly in unmanned long-term operations or printing in extreme environments.To address these issues,we developed a process monitoring and closed-loop feedback control strategy for the 3D printing process.Real-time printing image data were captured and analyzed using a well-trained neural network model,and a real-time control module-enabled closed-loop feedback control of the flow rate was developed.The neural network model,which was based on image processing and artificial intelligence,enabled the recognition of flow rate values with an accuracy of 94.70%.The experimental results showed significant improvements in both the surface performance and mechanical properties of printed composites,with three to six times improvement in tensile strength and elastic modulus,demonstrating the effectiveness of the strategy.This study provides a generalized process monitoring and feedback control method for the 3D printing of continuous fiber-reinforced composites,and offers a potential solution for remote online monitoring and closed-loop adjustment in unmanned or extreme space environments.
基金supported by the National Key R&D Program of China(No.2022YFB3203900).
文摘Integrating thick/thin film sensors into component systems has emerged as a prevalent approach for monitoring in extreme environments.However,traditional vapor deposition methods face obstacles,including complex fabrication processes and the degradation of sensitive materials at extremely high temperatures.This work delineates the development of a polysilazane composite dual-layer thick-film Negative Temperature Coefficient(NTC)thermistor characterized by its suitability for extreme temperatures and robust bond strength achieved through an advanced near-net-shape printing methodology.High-temperature resistant La(Ca)CrO_(3)/polysilazane films were printed as the sensitive layer,while a dense layer formed by Cr_(2)O_(3)/polysilazane was used as the protective layer.The bilayer structure resulted in a 2.5-fold increase in adhesion strength compared to the single-layer La(Ca)CrO_(3)/polysilazane films.Experimental results indicate that the dual-layer thick-film NTC thermistor can be operated long-term at 1300℃ with a resistance drift rate of 0.9%/h and survive short-term exposure to temperatures up to 1550℃.As a proof of concept,this work applied 3D printing technology to fabricate a polysilazane composite dual-layer thick-film NTC thermistor on the surface of turbine blades and demonstrated its functionality under flame impingement at nearly 1300℃.Such flexible 3D printing techniques pave the way for a new paradigm in manufacturing sensors capable of withstanding ultra-high temperatures.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(T2121004)Key Programme(52235007)National Outstanding Youth Foundation of China(52325504).
文摘Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.
基金supported by the National Natural Science Foundation of China(72022018,72091210)Youth Innovation Promotion Association,Chinese Academy of Sciences(2021454).
文摘With the maturation of emerging information technologies(Internet of Things,cloud computing,and big data),distributed manufacturing has emerged as an important model for future manufacturing.3D printing,with its integrated molding and design freedom,is a powerful catalyst for distributed manufacturing.This paper investigates the integrated production and transportation scheduling problem in distributed 3D printing.To solve this problem,we decompose the original problem into three sub-problems and design a multilevel optimization algorithm.We employ a genetic algorithm in the outer-level optimization to determine the optimal allocation of parts to machines.In the inner-level optimization,we utilize a simulated annealing algorithm to tackle the vehicle routing problem during the transportation stage followed by a local search algorithm to address the scheduling problem encountered during the production stage.Our algorithm is validated using real data from a 3D printing company,and the results show that our algorithm can obtain solutions that are the same as or better than those of Gurobi in a reasonable time for small-sized instances.Additionally,three types of initial methods are tested on large-sized instances to verify the efficiency of the proposed algorithm,and some interesting insights are also revealed and discussed.
基金supported by National Natural Science Foundation of China(Grant No.52305398)Chengdu University of Information Technology Project(Grant No.KYTZ202145).
文摘Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat.However,the presence of resin vats limits the printing of multiscale multimaterial structures.In this context,a novel 3D printing process is presented in which a cured structure is produced from acoustically levitated droplets without a physical vat.This enables the printing process to achieve high flexibility in the printing orientation and material supply.In pursuit of the envisioned 3D acoustic levitation printing strategy,acoustic levitation technology was utilized to suspend a photosensitive resin.Objects with small features were successfully produced by projecting patterns onto levitated resin droplets.Transforming printing orientations allows the fabrication of multiscale structures.Levitating resin droplets on-demand enables the rapid replacement of materials,thereby realizing effortless multimaterial 3D printing.By exploiting the flexibility of printing on levitation resin droplets,the capability of 3D printing on existing objects was established.Finally,an interesting example was illustrated,in which an object integrating liquid,gas,and solid materials was fabricated using the proposed 3D printing strategy.The results show that 3D printing on levitated droplets is feasible for fabricating multiscale and multimaterial objects,which contributes to the development of new 3D printing methods and potential applications.
