An ultraviolet（UV） curable support material pre-polymer for three dimensional printing was prepared based on the synergistic effect between PEO-PPO-PEO tri-block copolymer（F127） and polyethylene glycol （400） di-...An ultraviolet（UV） curable support material pre-polymer for three dimensional printing was prepared based on the synergistic effect between PEO-PPO-PEO tri-block copolymer（F127） and polyethylene glycol （400） di-acrylate（SR344）. The effects of jetting conditions, thermal stability, curing time, mechanical properties and shrinking rate on printing models were studied. The situation of removing support material from build model was investigated after building progress was completed. The experimental result shows that when F127 is 6.0wt%, SR344 is 20.0wt%, 4-Methoxy phenol is 0.15wt% and Irgacure 2959 is 1.5wt%, the support material pre-polymer could be jetted out from the nozzles smoothly during building up of three dimensional printing models at 50-55 ℃. In addition, the support material could be removed easily from building model without spoiling the model; furthermore, the forming precision of building model is improved.展开更多
Part orientation is one of the important factors in manufacturing with three dimensional printing(3DP)of rapid prototyping system.The minimum building time,being achieved by the part’s minimum building height and min...Part orientation is one of the important factors in manufacturing with three dimensional printing(3DP)of rapid prototyping system.The minimum building time,being achieved by the part’s minimum building height and minimum width in 3DP’s y direction,is set as the objective of optimizing the part orientation.Genetic algorithm is adopted to find the minimum building height of parts and then ergodic searching is used to get the minimum width of part in y direction.A corresponding program for optimizing part orientation in 3DP was developed.Tests show the proposed approach is effective and fast.展开更多
The primary objective of this article is to explore effects of latest development in the area of three dimensional(3D)printing&to assess its abilities,and further undertake helpful reporting.Here the focus is to a...The primary objective of this article is to explore effects of latest development in the area of three dimensional(3D)printing&to assess its abilities,and further undertake helpful reporting.Here the focus is to assess ad vantages of 3D printing in orthopedics and analyze how 3D printed models help solve complex 3D orthopedics distortions.This study identified that 3D models manufactured by 3D printing models reduce medical parts de velopment cost and surgical planning time.Integrating 3D printing with orthopaedics helps in understanding the conditions of problems and achieving the operation succssfully.This technology can enable doctors/surgeons to design,produce,recreate and plan operations more accurately,carefully,and economicaly.3D models can assist specialists with a visual comprehension of the patient-particular pathology and life structures.Innovation in 3D printing initiated a scaffold for the virtual outline and execution of medical procedures.This research proposes the utilisation of 3D printers as an elective procedure for the fabrication of parts.It empowers surgeons/patients for better raining,education and research.In the future,there is a foreseeable expansion of additive manufacturing in orthopedics.展开更多
BACKGROUND Floating thrombus within the thoracic aorta is a rare entity but may cause systemic embolism.The pathogenesis of floating aortic thrombi is not yet fully understood.No definitive guidelines are available fo...BACKGROUND Floating thrombus within the thoracic aorta is a rare entity but may cause systemic embolism.The pathogenesis of floating aortic thrombi is not yet fully understood.No definitive guidelines are available for the management of floating aortic thrombus.CASE SUMMARY We report a 48-year-old patient,without a history of trauma and infection,who presented with sudden severe back pain.A floating thrombus within the aortic arch was found by computed tomography angiography(CTA).No evidence of coagulopathies was found.However,with the assistance of a three dimensionalprinted model,this floating thrombus was identified to be caused by occult aortic dissection(AD).Subsequently,an emergency thoracic endovascular repair was performed.The patient’s back pain was rapidly alleviated postoperatively.CTA at 1 year showed no filling defect in the stent-graft and aorta.CONCLUSION Occult AD is a potential factor causing floating aortic thrombi,endovascular stent-graft exclusion may be an optimal therapeutic choice with promising results.Moreover,the combination of CTA and three dimensional-printed models can contribute to the diagnosis and treatment of floating aortic thrombi due to occult AD.展开更多
The anatomy of the human liver is complex,and the vascular system is highly variable.Moreover,the use of traditional com-puted tomography(CT)two-dimensional(2D)images to recon-struct the tissue and organs requires exp...The anatomy of the human liver is complex,and the vascular system is highly variable.Moreover,the use of traditional com-puted tomography(CT)two-dimensional(2D)images to recon-struct the tissue and organs requires experienced doctors and lim-its the sharing and discussion of therapeutic plans[1].展开更多
Three dimensional printing（3DP） is a solid freeform fabrication technology which employs powder processing and a liquid binder material in the construction of parts in a layer-wise manner. 3DP can accommodate much g...Three dimensional printing（3DP） is a solid freeform fabrication technology which employs powder processing and a liquid binder material in the construction of parts in a layer-wise manner. 3DP can accommodate much geometric outline and be made with many materials due to its unprecedented flexibility. The technology can control over the material composition, microstructure and surface texture so it attracts great attentions in the pharmaceutics field. 3DP can offer many novel strategies and approaches for the research and is widely focused in the field of the controlled-release drug delivery systems. Through consulting a large number of documents the current development and the technical characteristics of 3DP in pharmaceutics field are discussed and reviewed. It is expected that 3DP technique may play a tremendous role in pharmaceutics field in the future.Three dimensional printing （3DP） is a solid freeform fabrication technology which employs powder processing and a liquid binder material in the construction of parts in a layer-wise manner. 3DP can accommodate much geometric outline and be made with many materials due to its unprecedented flexibility. The technology can control over the material composition, microstructure and surface texture so it attracts great attentions in the pharmaceutics field. 3DP can offer many novel strategies and approaches for the research and is widely focused in the field of the controlled-release drug delivery systems. Through consulting a large number of documents the current development and the technical characteristics of 3DP in pharmaceutics field are discussed and reviewed. It is expected that 3DP technique may play a tremendous role in pharmaceutics field in the future.展开更多
Activity 1Think about the following questions and write down your answers before reading the text.1.How might 3D-printed buildings change the way we think about traditional construction methods?2.In what ways could la...Activity 1Think about the following questions and write down your answers before reading the text.1.How might 3D-printed buildings change the way we think about traditional construction methods?2.In what ways could large-scale 3D-printed buildings impact local communities?Activity 2Read the text,and try to fill in the blank.展开更多
A 3D-printed dual-band dual-polarization gap waveguide(GWG)slot antenna array is presented for Ku-band satellite communications(SATCOMs)in this paper.Two stacked GWGs excite the quasi-TE420 and quasi-TE240 modes in th...A 3D-printed dual-band dual-polarization gap waveguide(GWG)slot antenna array is presented for Ku-band satellite communications(SATCOMs)in this paper.Two stacked GWGs excite the quasi-TE420 and quasi-TE240 modes in the cavity separately through orthogonal slots.An unequal power divider with a large power division ratio is proposed based on a ridge gap waveguide(RGW).Two power tapering distribution networks are realized for dual polarizations,and the sidelobe level(SLL)is suppressed.The antenna is fabricated in parts by direct metal laser sintering(DMLS),and the whole antenna is obtained by screw assembly.The measured impedance bandwidth well covers both the transmitting band(Tx,from 14.0 GHz to 14.5 GHz)and the receiving band(Rx,from 12.25 GHz to 12.75 GHz)required for Ku-band SATCOMs.Measurement results show that the maximum gain reaches 25.6 dBi,and that the radiation efficiency of the dual-band is>72%.展开更多
Wide-ranging biomedical applications spanning both research and clinical settings rely on microinjection protocols that involve using a long,hollow microneedle to deliver foreign substances directly into biological ta...Wide-ranging biomedical applications spanning both research and clinical settings rely on microinjection protocols that involve using a long,hollow microneedle to deliver foreign substances directly into biological targets,such as embryos.Unfortunately,conventional microneedles are prone to clogging—e.g.,cytoplasmic material from an embryo becoming lodged inside the needle tip during penetration,thereby obstructing delivery—motivating researchers to use top-down microfabrication techniques to modify needle tips and reduce such failure modes.Recent advancements for the submicron-scale additive manufacturing approach,“Two-Photon Direct Laser Writing(DLW)”,offer a new,bottom-up pathway for re-architecting microneedle tips to address clogging susceptibility via geometric means.Here,we investigate this potential by 3D printing monolithic 650-μm-tall,15-μm-diameter hollow microneedles comprising architectural features designed to remediate clogging phenomena:(i)a solid,fine-point tip,(ii)multiple side ports(i.e.,perpendicular to the insertion direction),and(iii)an internal microfilter.Serial microinjection experiments with live zebrafish embryos reveal that the 3D microneedles yield enhanced delivery performance without any instances of complete blockages that are pervasive among both standard glass and 3Dprinted control microneedles.These findings suggest that DLW-based 3D printing holds distinctive promise for highprecision microinjection applications,particularly in scenarios involving extensive serial injections or critical payloads and targets.展开更多
Additive manufacturing(AM),or 3D printing,has fundamentally reshaped part fabrication,transitioning from traditional subtractive methods toward incremental layer-by-layer deposition guided by digital models.This shift...Additive manufacturing(AM),or 3D printing,has fundamentally reshaped part fabrication,transitioning from traditional subtractive methods toward incremental layer-by-layer deposition guided by digital models.This shift offers significant advantages,including reduced material waste,geometric freedom,rapid prototyping,and customization.For structural composites-materials combining high-strength fibers within polymer matrices-AM presents remarkable potential for producing lightweight,high-performance components in aerospace,automotive,sports equipment,and renewable energy sectors.Despite considerable enthusiasm,practical implementation of composite AM remains limited.展开更多
Three dimensional(3D)printing technology by direct ink writing(DIW)is an innovative complex shaping technology,possessing advantages of flexibility in fabrication,high efficiency,low cost,and environmental-friendlines...Three dimensional(3D)printing technology by direct ink writing(DIW)is an innovative complex shaping technology,possessing advantages of flexibility in fabrication,high efficiency,low cost,and environmental-friendliness.Herein,3D printing of complex alumina ceramic parts via DIW using thermally induced solidification with carrageenan swelling was investigated.The rheological properties of the slurry under different thermally-induced modes were systematically studied.The solidification properties of thermally-induced pastes with varying contents of carrageenan were optimized.The experimental results showed that the optimized paste consisting of 0.4 wt%carrageenan could be rapidly solidified at about 55℃,which could print inclined-plane more than 60°in vertical without support,resulting in better homogeneity of the green body.A nearly pore-free structure was obtained after sintering at 1600℃ for 2 h.展开更多
Glass materials are essential for microsystems applications in fields ranging from optics and photonics to microfluidics and biomedicine,which has driven growing interest in additive manufacturing—or“three-dimension...Glass materials are essential for microsystems applications in fields ranging from optics and photonics to microfluidics and biomedicine,which has driven growing interest in additive manufacturing—or“three-dimensional(3D)printing”—to enable glass micro/nanotechnologies.Notably,the recent discovery that 3D-nanostructured fused silica glass components can be produced via“two-photon direct laser writing(DLW)”of hybrid organic-inorganic polyhedral oligomeric silsesquioxanes(POSS)-based resins holds unique promise,particularly due to the advantages of sinterless,low-temperature(i.e.,650℃)post-processing.At present,however,it remains unknown how implementing such methodologies to 3D print larger glass microstructures(e.g.,with≥25-μm-thick features)affects critical material properties,such as the ultimate optical and mechanical characteristics.To address this knowledge gap,here we investigate DLW-printed feature size as a key determinant of the optical and mechanical properties of POSS-based fused silica glass microstructures.Experiments for DLW-printed microlenses reveal comparable optical transparency for initial thicknesses up to 40μm,but increasing to 60μm significantly reduces light transmission from 87.87±1.18%to 63.57±5.10%.Similarly,compressive loading studies for hollow glass cylindrical microstructures show consistent behavior for initial DLW-printed wall thicknesses up to 30μm,but significant performance degradation beyond—e.g.,Young’s modulus decreasing from 251.6±71.9 to 99.7±63.9 MPa for the 30 to 40μm cases,respectively.As an exemplar with relevance to biomedical microinjection applications,we harness this new knowledge to DLW-print POSS-based glass microneedle arrays(MNAs)and demonstrate their ability to penetrate into a medium not possible using standard polymer MNAs.In combination,this study establishes critical optical and mechanical benchmarks that underlie the utility of DLW 3D-printed POSS-based fused silica glass microstructures in emerging applications.展开更多
Droplet splitting technology presents considerable potential for advancing applica-tions in sample encapsulation,manipulation,chemical reaction control,and preci-sion measurement systems.However,existing methodologies...Droplet splitting technology presents considerable potential for advancing applica-tions in sample encapsulation,manipulation,chemical reaction control,and preci-sion measurement systems.However,existing methodologies frequently encounter limitations related to complex operation and high cost.To address the need for controllable,high-precision,and cost-efficient droplet splitting,this study combines three-dimensional printing technology with superhydrophobic surface modification to fabricate pyramid microstructures with customized splitting functionalities.The pyramidal sharp edges act as“fluidic blades”to split droplets through the synergistic interaction of edge-induced capillary forces and inertial forces generated at the liquid film periphery during spreading dynamics.Upon penetration by the pyramid apex,the droplet forms an annular liquid ring that subsequently fragments into sub-droplets,enabling programmable splitting.A comprehensive experimental and computational framework was developed to investigate splitting dynamics,force distribution pat-terns,and geometric dependence of pyramid structures on splitting performance.Results indicate that increased Weber numbers,larger droplet volumes,and reduced pyramid apex angles markedly improve splitting controllability.Additionally,six-and 12-sided pyramid-based splitting/collection devices were engineered to demonstrate practical implementations,including on-demand droplet splitting and liquid marble synthesis.This work establishes a scalable,low-cost platform for precision droplet manipulation with significant implications for microfluidic devices and lab-on-a-chip technologies.展开更多
Three-dimensional(3D)printing allows for the construction of complex structures.However,3D-printing vertical structures with a high aspect ratio remains a pending challenge,especially when a high lateral resolution is...Three-dimensional(3D)printing allows for the construction of complex structures.However,3D-printing vertical structures with a high aspect ratio remains a pending challenge,especially when a high lateral resolution is required.Here,to address this challenge,we propose and demonstrate micro-3D sculptured metastructures with deep trenches of 1:4(width:height)aspect ratio for sub-10µm resolution.Our construction relies on two-photon polymerization for a 3D-pattern with its trenches,followed by electroplating of a thick metal film and its dry etching to remove the seed layer.To test the proposed fabrication process,we built up three-dimensional RF metastructures showcasing the depth effect as the third dimension.Using the numerical solutions,we custom-tailored these metastructure resonators to fall within a specific resonance frequency range of 4-6 GHz while undertaking comparative analyses regarding overall footprint,quality factor,and resonance frequency shift as a function of their cross-sectional aspect ratio.The proposed process flow is shown to miniaturize metal footprint and tune the resonance frequency of these thick 3Dmetastructures while increasing their quality factor.These experimental findings indicate that this method of producing trenches via 3D-printing provides rich opportunities to implement high-aspect-ratio,complex structures.展开更多
Experiment of rapid prototyping (RP) is a multi-level and multi-factor problem with long process cycle. As powder-based RP method, three dimensional printing (3DP), and selective laser sintering (SLS) are the most pro...Experiment of rapid prototyping (RP) is a multi-level and multi-factor problem with long process cycle. As powder-based RP method, three dimensional printing (3DP), and selective laser sintering (SLS) are the most prominent RP methods for their flexibility in material selecting. The research of 3DP process shows that much experiments work can be greatly decreased by the method of uniform design with restricted mixtures for RP products’ performance to its forming material. Then, according to backward regression methods, the binomial and inverse terms nonlinear regression equations were set up by statistic analysis and computation. Together with evaluation function method, multi-object optimization model for performance of products to the powder mixtures was developed, and the optimization problem was solved by software MATLAB. After that, the optimum results were solved and tested by experiment with the same condition as before. Differences between the calculation results and testing results, which including product’s density, compression strength, surface evaluation, and deformation in three dimensions, are less than 10%, and have the same error direction. Uniform design method for regression and optimization was proved to be an excellent method to obtain optimum results for multi-level and multi-factor experiments of RP and other process which have a long processing cycle.展开更多
Locking-steel-pipe(LSP)piles connect with adjacent joints to form a pile row enclosure structure.Due to the advantages of quick construction,efficiency in installation,and recycle utilization,the connected LSP piles a...Locking-steel-pipe(LSP)piles connect with adjacent joints to form a pile row enclosure structure.Due to the advantages of quick construction,efficiency in installation,and recycle utilization,the connected LSP piles are frequently used as retaining structure in deep excavation.However,systematic studies of the deformation mechanism of the LSP pile retaining structure are rarely reported,and it still lack of experimental evidence to optimize the design.In this study,a braced supported excavation experimental model test in sand was designed and conducted to investigate the deformation characteristics of LSP pile retaining structure.Three dimensional(3D)printing technique was creatively applied to manufacture LSP model piles.The experimental results show that,a“S”shaped distribution of bending moments is observed along pile shaft when excavation is executed;the deflection of pile shaft develops deep-seated movements toward the excavation side as excavation went deeper,resulting in a“bowl”ground settlement.With the deflection of LSP piles,a rotating trend was occurred between pairs of locking joint,and the severe open deformation of locking joint arose on excavation side.There was a gradual reduction in earth pressure behind the LSP pile retaining wall with excavation depth.The earth pressure between two struts level had no obvious changing,owing to the supported effect of inner struts.展开更多
基金Funded by National High-tech Research and Development Projects of China(No. 2002AA6Z3083)
文摘An ultraviolet（UV） curable support material pre-polymer for three dimensional printing was prepared based on the synergistic effect between PEO-PPO-PEO tri-block copolymer（F127） and polyethylene glycol （400） di-acrylate（SR344）. The effects of jetting conditions, thermal stability, curing time, mechanical properties and shrinking rate on printing models were studied. The situation of removing support material from build model was investigated after building progress was completed. The experimental result shows that when F127 is 6.0wt%, SR344 is 20.0wt%, 4-Methoxy phenol is 0.15wt% and Irgacure 2959 is 1.5wt%, the support material pre-polymer could be jetted out from the nozzles smoothly during building up of three dimensional printing models at 50-55 ℃. In addition, the support material could be removed easily from building model without spoiling the model; furthermore, the forming precision of building model is improved.
基金the Natural Science Foundation Hubei Province,China(2005ABA181)
文摘Part orientation is one of the important factors in manufacturing with three dimensional printing(3DP)of rapid prototyping system.The minimum building time,being achieved by the part’s minimum building height and minimum width in 3DP’s y direction,is set as the objective of optimizing the part orientation.Genetic algorithm is adopted to find the minimum building height of parts and then ergodic searching is used to get the minimum width of part in y direction.A corresponding program for optimizing part orientation in 3DP was developed.Tests show the proposed approach is effective and fast.
文摘The primary objective of this article is to explore effects of latest development in the area of three dimensional(3D)printing&to assess its abilities,and further undertake helpful reporting.Here the focus is to assess ad vantages of 3D printing in orthopedics and analyze how 3D printed models help solve complex 3D orthopedics distortions.This study identified that 3D models manufactured by 3D printing models reduce medical parts de velopment cost and surgical planning time.Integrating 3D printing with orthopaedics helps in understanding the conditions of problems and achieving the operation succssfully.This technology can enable doctors/surgeons to design,produce,recreate and plan operations more accurately,carefully,and economicaly.3D models can assist specialists with a visual comprehension of the patient-particular pathology and life structures.Innovation in 3D printing initiated a scaffold for the virtual outline and execution of medical procedures.This research proposes the utilisation of 3D printers as an elective procedure for the fabrication of parts.It empowers surgeons/patients for better raining,education and research.In the future,there is a foreseeable expansion of additive manufacturing in orthopedics.
基金Sichuan Foundation of Science and Technology,No.2019YJ0066Sichuan Foundation of Science and Technology,No.2019YFS0346.
文摘BACKGROUND Floating thrombus within the thoracic aorta is a rare entity but may cause systemic embolism.The pathogenesis of floating aortic thrombi is not yet fully understood.No definitive guidelines are available for the management of floating aortic thrombus.CASE SUMMARY We report a 48-year-old patient,without a history of trauma and infection,who presented with sudden severe back pain.A floating thrombus within the aortic arch was found by computed tomography angiography(CTA).No evidence of coagulopathies was found.However,with the assistance of a three dimensionalprinted model,this floating thrombus was identified to be caused by occult aortic dissection(AD).Subsequently,an emergency thoracic endovascular repair was performed.The patient’s back pain was rapidly alleviated postoperatively.CTA at 1 year showed no filling defect in the stent-graft and aorta.CONCLUSION Occult AD is a potential factor causing floating aortic thrombi,endovascular stent-graft exclusion may be an optimal therapeutic choice with promising results.Moreover,the combination of CTA and three dimensional-printed models can contribute to the diagnosis and treatment of floating aortic thrombi due to occult AD.
基金supported by grants from Jilin Scientific and Technological Development Program(20200403090SF)The Health Special Foundation of Jilin Province of China(2020sczt029).
文摘The anatomy of the human liver is complex,and the vascular system is highly variable.Moreover,the use of traditional com-puted tomography(CT)two-dimensional(2D)images to recon-struct the tissue and organs requires experienced doctors and lim-its the sharing and discussion of therapeutic plans[1].
文摘Three dimensional printing（3DP） is a solid freeform fabrication technology which employs powder processing and a liquid binder material in the construction of parts in a layer-wise manner. 3DP can accommodate much geometric outline and be made with many materials due to its unprecedented flexibility. The technology can control over the material composition, microstructure and surface texture so it attracts great attentions in the pharmaceutics field. 3DP can offer many novel strategies and approaches for the research and is widely focused in the field of the controlled-release drug delivery systems. Through consulting a large number of documents the current development and the technical characteristics of 3DP in pharmaceutics field are discussed and reviewed. It is expected that 3DP technique may play a tremendous role in pharmaceutics field in the future.Three dimensional printing （3DP） is a solid freeform fabrication technology which employs powder processing and a liquid binder material in the construction of parts in a layer-wise manner. 3DP can accommodate much geometric outline and be made with many materials due to its unprecedented flexibility. The technology can control over the material composition, microstructure and surface texture so it attracts great attentions in the pharmaceutics field. 3DP can offer many novel strategies and approaches for the research and is widely focused in the field of the controlled-release drug delivery systems. Through consulting a large number of documents the current development and the technical characteristics of 3DP in pharmaceutics field are discussed and reviewed. It is expected that 3DP technique may play a tremendous role in pharmaceutics field in the future.
文摘Activity 1Think about the following questions and write down your answers before reading the text.1.How might 3D-printed buildings change the way we think about traditional construction methods?2.In what ways could large-scale 3D-printed buildings impact local communities?Activity 2Read the text,and try to fill in the blank.
基金Project supported by the National Natural Science Foundation of China(Nos.62321001 and 62301065)。
文摘A 3D-printed dual-band dual-polarization gap waveguide(GWG)slot antenna array is presented for Ku-band satellite communications(SATCOMs)in this paper.Two stacked GWGs excite the quasi-TE420 and quasi-TE240 modes in the cavity separately through orthogonal slots.An unequal power divider with a large power division ratio is proposed based on a ridge gap waveguide(RGW).Two power tapering distribution networks are realized for dual polarizations,and the sidelobe level(SLL)is suppressed.The antenna is fabricated in parts by direct metal laser sintering(DMLS),and the whole antenna is obtained by screw assembly.The measured impedance bandwidth well covers both the transmitting band(Tx,from 14.0 GHz to 14.5 GHz)and the receiving band(Rx,from 12.25 GHz to 12.75 GHz)required for Ku-band SATCOMs.Measurement results show that the maximum gain reaches 25.6 dBi,and that the radiation efficiency of the dual-band is>72%.
基金supported in part by U.S.National Institutes of Health(NIH)Award Numbers 1R41GM153053 and 1R41MH135827U.S.National Science Foundation(NSF)Award Numbers 1943356 and 1938527Maryland Industrial Partnerships(MIPS)Award Numbers 6523 and 7422.
文摘Wide-ranging biomedical applications spanning both research and clinical settings rely on microinjection protocols that involve using a long,hollow microneedle to deliver foreign substances directly into biological targets,such as embryos.Unfortunately,conventional microneedles are prone to clogging—e.g.,cytoplasmic material from an embryo becoming lodged inside the needle tip during penetration,thereby obstructing delivery—motivating researchers to use top-down microfabrication techniques to modify needle tips and reduce such failure modes.Recent advancements for the submicron-scale additive manufacturing approach,“Two-Photon Direct Laser Writing(DLW)”,offer a new,bottom-up pathway for re-architecting microneedle tips to address clogging susceptibility via geometric means.Here,we investigate this potential by 3D printing monolithic 650-μm-tall,15-μm-diameter hollow microneedles comprising architectural features designed to remediate clogging phenomena:(i)a solid,fine-point tip,(ii)multiple side ports(i.e.,perpendicular to the insertion direction),and(iii)an internal microfilter.Serial microinjection experiments with live zebrafish embryos reveal that the 3D microneedles yield enhanced delivery performance without any instances of complete blockages that are pervasive among both standard glass and 3Dprinted control microneedles.These findings suggest that DLW-based 3D printing holds distinctive promise for highprecision microinjection applications,particularly in scenarios involving extensive serial injections or critical payloads and targets.
文摘Additive manufacturing(AM),or 3D printing,has fundamentally reshaped part fabrication,transitioning from traditional subtractive methods toward incremental layer-by-layer deposition guided by digital models.This shift offers significant advantages,including reduced material waste,geometric freedom,rapid prototyping,and customization.For structural composites-materials combining high-strength fibers within polymer matrices-AM presents remarkable potential for producing lightweight,high-performance components in aerospace,automotive,sports equipment,and renewable energy sectors.Despite considerable enthusiasm,practical implementation of composite AM remains limited.
基金The authors gratefully acknowledge the financial support from the National Key R&D Program of China(Grant No.2017YFB0310400).
文摘Three dimensional(3D)printing technology by direct ink writing(DIW)is an innovative complex shaping technology,possessing advantages of flexibility in fabrication,high efficiency,low cost,and environmental-friendliness.Herein,3D printing of complex alumina ceramic parts via DIW using thermally induced solidification with carrageenan swelling was investigated.The rheological properties of the slurry under different thermally-induced modes were systematically studied.The solidification properties of thermally-induced pastes with varying contents of carrageenan were optimized.The experimental results showed that the optimized paste consisting of 0.4 wt%carrageenan could be rapidly solidified at about 55℃,which could print inclined-plane more than 60°in vertical without support,resulting in better homogeneity of the green body.A nearly pore-free structure was obtained after sintering at 1600℃ for 2 h.
基金support of the Clark School of Engineering’s Materials Characterization Labsupported in part by US National Institutes of Health(NIH)Award Numbers 1R41GM153053 and 1R41MH135827+2 种基金US National Science Foundation(NSF)Award Numbers 1943356 and 1938527Maryland Industrial Partnerships(MIPS)Award Numbers 6523 and 7422US National Science Foundation grants CMMI1943356,DGE2236417,and DGE2139757。
文摘Glass materials are essential for microsystems applications in fields ranging from optics and photonics to microfluidics and biomedicine,which has driven growing interest in additive manufacturing—or“three-dimensional(3D)printing”—to enable glass micro/nanotechnologies.Notably,the recent discovery that 3D-nanostructured fused silica glass components can be produced via“two-photon direct laser writing(DLW)”of hybrid organic-inorganic polyhedral oligomeric silsesquioxanes(POSS)-based resins holds unique promise,particularly due to the advantages of sinterless,low-temperature(i.e.,650℃)post-processing.At present,however,it remains unknown how implementing such methodologies to 3D print larger glass microstructures(e.g.,with≥25-μm-thick features)affects critical material properties,such as the ultimate optical and mechanical characteristics.To address this knowledge gap,here we investigate DLW-printed feature size as a key determinant of the optical and mechanical properties of POSS-based fused silica glass microstructures.Experiments for DLW-printed microlenses reveal comparable optical transparency for initial thicknesses up to 40μm,but increasing to 60μm significantly reduces light transmission from 87.87±1.18%to 63.57±5.10%.Similarly,compressive loading studies for hollow glass cylindrical microstructures show consistent behavior for initial DLW-printed wall thicknesses up to 30μm,but significant performance degradation beyond—e.g.,Young’s modulus decreasing from 251.6±71.9 to 99.7±63.9 MPa for the 30 to 40μm cases,respectively.As an exemplar with relevance to biomedical microinjection applications,we harness this new knowledge to DLW-print POSS-based glass microneedle arrays(MNAs)and demonstrate their ability to penetrate into a medium not possible using standard polymer MNAs.In combination,this study establishes critical optical and mechanical benchmarks that underlie the utility of DLW 3D-printed POSS-based fused silica glass microstructures in emerging applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:U23A20632,52275420National Key R&D Programof China,Grant/Award Number:2022YFB3403304。
文摘Droplet splitting technology presents considerable potential for advancing applica-tions in sample encapsulation,manipulation,chemical reaction control,and preci-sion measurement systems.However,existing methodologies frequently encounter limitations related to complex operation and high cost.To address the need for controllable,high-precision,and cost-efficient droplet splitting,this study combines three-dimensional printing technology with superhydrophobic surface modification to fabricate pyramid microstructures with customized splitting functionalities.The pyramidal sharp edges act as“fluidic blades”to split droplets through the synergistic interaction of edge-induced capillary forces and inertial forces generated at the liquid film periphery during spreading dynamics.Upon penetration by the pyramid apex,the droplet forms an annular liquid ring that subsequently fragments into sub-droplets,enabling programmable splitting.A comprehensive experimental and computational framework was developed to investigate splitting dynamics,force distribution pat-terns,and geometric dependence of pyramid structures on splitting performance.Results indicate that increased Weber numbers,larger droplet volumes,and reduced pyramid apex angles markedly improve splitting controllability.Additionally,six-and 12-sided pyramid-based splitting/collection devices were engineered to demonstrate practical implementations,including on-demand droplet splitting and liquid marble synthesis.This work establishes a scalable,low-cost platform for precision droplet manipulation with significant implications for microfluidic devices and lab-on-a-chip technologies.
基金the financial support in part from TUBITAK 20AG001,and 121C266HVD also acknowledges the support from TUBA and TUBITAK 2247-A National Leader Researchers Program(121C266)。
文摘Three-dimensional(3D)printing allows for the construction of complex structures.However,3D-printing vertical structures with a high aspect ratio remains a pending challenge,especially when a high lateral resolution is required.Here,to address this challenge,we propose and demonstrate micro-3D sculptured metastructures with deep trenches of 1:4(width:height)aspect ratio for sub-10µm resolution.Our construction relies on two-photon polymerization for a 3D-pattern with its trenches,followed by electroplating of a thick metal film and its dry etching to remove the seed layer.To test the proposed fabrication process,we built up three-dimensional RF metastructures showcasing the depth effect as the third dimension.Using the numerical solutions,we custom-tailored these metastructure resonators to fall within a specific resonance frequency range of 4-6 GHz while undertaking comparative analyses regarding overall footprint,quality factor,and resonance frequency shift as a function of their cross-sectional aspect ratio.The proposed process flow is shown to miniaturize metal footprint and tune the resonance frequency of these thick 3Dmetastructures while increasing their quality factor.These experimental findings indicate that this method of producing trenches via 3D-printing provides rich opportunities to implement high-aspect-ratio,complex structures.
基金Supported by the Ph. D’s Start-up Fund in University of Shanghai for Science and Technology, China (No. 10D305)
文摘Experiment of rapid prototyping (RP) is a multi-level and multi-factor problem with long process cycle. As powder-based RP method, three dimensional printing (3DP), and selective laser sintering (SLS) are the most prominent RP methods for their flexibility in material selecting. The research of 3DP process shows that much experiments work can be greatly decreased by the method of uniform design with restricted mixtures for RP products’ performance to its forming material. Then, according to backward regression methods, the binomial and inverse terms nonlinear regression equations were set up by statistic analysis and computation. Together with evaluation function method, multi-object optimization model for performance of products to the powder mixtures was developed, and the optimization problem was solved by software MATLAB. After that, the optimum results were solved and tested by experiment with the same condition as before. Differences between the calculation results and testing results, which including product’s density, compression strength, surface evaluation, and deformation in three dimensions, are less than 10%, and have the same error direction. Uniform design method for regression and optimization was proved to be an excellent method to obtain optimum results for multi-level and multi-factor experiments of RP and other process which have a long processing cycle.
基金supported by the National Natural Science Foundation of China(Grant Nos.41807262,51878185,and 41867034)the China Postdoctoral Science Foundation(No.2019M653308)+2 种基金the Innovative Research Team Program of Guangxi Natural Science Foundation(Grant No.2016GXNSFGA380008)the Bagui Scholars Program(Grant No.2016A31)the China Scholarship Council(CSC)(Grant No.201906660001).
文摘Locking-steel-pipe(LSP)piles connect with adjacent joints to form a pile row enclosure structure.Due to the advantages of quick construction,efficiency in installation,and recycle utilization,the connected LSP piles are frequently used as retaining structure in deep excavation.However,systematic studies of the deformation mechanism of the LSP pile retaining structure are rarely reported,and it still lack of experimental evidence to optimize the design.In this study,a braced supported excavation experimental model test in sand was designed and conducted to investigate the deformation characteristics of LSP pile retaining structure.Three dimensional(3D)printing technique was creatively applied to manufacture LSP model piles.The experimental results show that,a“S”shaped distribution of bending moments is observed along pile shaft when excavation is executed;the deflection of pile shaft develops deep-seated movements toward the excavation side as excavation went deeper,resulting in a“bowl”ground settlement.With the deflection of LSP piles,a rotating trend was occurred between pairs of locking joint,and the severe open deformation of locking joint arose on excavation side.There was a gradual reduction in earth pressure behind the LSP pile retaining wall with excavation depth.The earth pressure between two struts level had no obvious changing,owing to the supported effect of inner struts.
