The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuato...The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.展开更多
Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of res...Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC slurry.In this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation treatment.This method was proven to effectively improve the curing ability of SiC slurry.The SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 30 s^(−1)).The curing thickness was 50μm with exposure time of only 5 s.Then,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during sintering.Complexshaped mullite-bond SiC ceramics were successfully fabricated.The flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 39.2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.展开更多
Sic-based composites are widely used as electromagnetic wave absorbers due to their excellent dielectric properties.However,the constraints associated with structural design and the intricacies of the preparation proc...Sic-based composites are widely used as electromagnetic wave absorbers due to their excellent dielectric properties.However,the constraints associated with structural design and the intricacies of the preparation process hinder their broader application.In this study,novel mullite anti-gyroid/SiC gyroid metastructures are designed to integrate the mechanical and electromagnetic wave(EMW)absorption properties of composite materials.Mullite anti-gyroid/SiC gyroid composites are fabricated utilizing a combination of digital light processing(DLP)three-dimensional(3D)printing and precursor infiltration and pyrolysis(PiP)processes.Through the modulation of structural units,the electromagnetic parameters can be effectively regulated,thus improving the impedance matching characteristics of the composites.The structural composites show outstanding EMW absorption properties,with a minimum reflection loss of-54 dB at a thickness of 1.9 mm and an effective absorption bandwidth of 3.20 GHz at a thickness of 2.2 mm.Furthermore,the PIP process significantly enhances the mechanical properties of the composites;compared with those of the mullite/SiC ceramics,the flexural strength of the composites is improved by 3.69-5.85 times(13.28±1.15 MPa vs.(49.05±1.07)-(77.78±3.72)MPa),and the compressive strength is improved by 4.59-13.58 times(8.55±0.90 MPa vs.(39.02±1.63)-(116.13±2.58)MPa).This approach offers a novel and effective method for fabricating structural composites with an expanded range of higher electromagnetic wave absorption properties and improved mechanical properties.展开更多
High performance hydroxyapatite(HA)ceramics with excellent densification and mechanical properties were successfully fabricated by digital light processing(DLP)three-dimensional(3D)printing technology.It was found tha...High performance hydroxyapatite(HA)ceramics with excellent densification and mechanical properties were successfully fabricated by digital light processing(DLP)three-dimensional(3D)printing technology.It was found that the sintering atmosphere of wet C02 can dramatically improve the densification process and thus lead to better mechanical properties.HA ceramics with a relative density of 97.12%and a three-point bending strength of 92.4 MPa can be achieved at a sintering temperature of 1300℃,which makes a solid foundation for application in bone engineering.Furthermore,a relatively high compressive strength of 4.09 MPa can be also achieved for a DLP-printed p-cell triply periodic minimum surface(TPMS)structure with a porosity of 74%,which meets the requirement of cancellous bone substitutes.A further cell proliferation test demonstrated that the sintering atmosphere of wet CO2 led to improve cell vitality after 7 days of cell culture Moreover,with the possible benefit from the bio-inspired structure,the 3D-printed TPMS structure significantly improved the cell vitality,which is crucial for early osteogenesis and osteointegration.展开更多
基金the National Natural Science Foundation of China(Nos.11572002 and 12002032)the China Postdoctoral Science Foundation(Nos.BX20200056 and 2020M670149)。
文摘The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.
基金supported by Shandong University−MSEA International Institute for Materials Genome Joint Innovation Center for Advanced Ceramics,and the Key Research and Development Projects of Shaanxi Province(Nos.2018ZDCXLGY-09-06 and 2021ZDLGY14-06).
文摘Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC slurry.In this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation treatment.This method was proven to effectively improve the curing ability of SiC slurry.The SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 30 s^(−1)).The curing thickness was 50μm with exposure time of only 5 s.Then,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during sintering.Complexshaped mullite-bond SiC ceramics were successfully fabricated.The flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 39.2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.
基金The authors gratefully acknowledged the financial support provided by the National Key R&D Program of China(No.2021YFB3701500)the Program of Shanghai Academic/Technology Research Leader(No.22XD1404000).
文摘Sic-based composites are widely used as electromagnetic wave absorbers due to their excellent dielectric properties.However,the constraints associated with structural design and the intricacies of the preparation process hinder their broader application.In this study,novel mullite anti-gyroid/SiC gyroid metastructures are designed to integrate the mechanical and electromagnetic wave(EMW)absorption properties of composite materials.Mullite anti-gyroid/SiC gyroid composites are fabricated utilizing a combination of digital light processing(DLP)three-dimensional(3D)printing and precursor infiltration and pyrolysis(PiP)processes.Through the modulation of structural units,the electromagnetic parameters can be effectively regulated,thus improving the impedance matching characteristics of the composites.The structural composites show outstanding EMW absorption properties,with a minimum reflection loss of-54 dB at a thickness of 1.9 mm and an effective absorption bandwidth of 3.20 GHz at a thickness of 2.2 mm.Furthermore,the PIP process significantly enhances the mechanical properties of the composites;compared with those of the mullite/SiC ceramics,the flexural strength of the composites is improved by 3.69-5.85 times(13.28±1.15 MPa vs.(49.05±1.07)-(77.78±3.72)MPa),and the compressive strength is improved by 4.59-13.58 times(8.55±0.90 MPa vs.(39.02±1.63)-(116.13±2.58)MPa).This approach offers a novel and effective method for fabricating structural composites with an expanded range of higher electromagnetic wave absorption properties and improved mechanical properties.
基金the National Key R&D Program of China(2017YFB1103500,2017YFB1103502).
文摘High performance hydroxyapatite(HA)ceramics with excellent densification and mechanical properties were successfully fabricated by digital light processing(DLP)three-dimensional(3D)printing technology.It was found that the sintering atmosphere of wet C02 can dramatically improve the densification process and thus lead to better mechanical properties.HA ceramics with a relative density of 97.12%and a three-point bending strength of 92.4 MPa can be achieved at a sintering temperature of 1300℃,which makes a solid foundation for application in bone engineering.Furthermore,a relatively high compressive strength of 4.09 MPa can be also achieved for a DLP-printed p-cell triply periodic minimum surface(TPMS)structure with a porosity of 74%,which meets the requirement of cancellous bone substitutes.A further cell proliferation test demonstrated that the sintering atmosphere of wet CO2 led to improve cell vitality after 7 days of cell culture Moreover,with the possible benefit from the bio-inspired structure,the 3D-printed TPMS structure significantly improved the cell vitality,which is crucial for early osteogenesis and osteointegration.
