Poly(vinyl alcohol)(PVA)hydrogels have garnered significant attention for tissue engineering,wound dressing,and electronic skin sensing applications.However,their poor mechanical performance severely restricts their m...Poly(vinyl alcohol)(PVA)hydrogels have garnered significant attention for tissue engineering,wound dressing,and electronic skin sensing applications.However,their poor mechanical performance severely restricts their multifunctional application in many scenarios.To address this limitation,PVA/tannic acid(TA)@carbon nanotubes(PVA/TA@CNTs)composite hydrogels with triple crosslinking networks were prepared through freezing-thawing and the solvent-induced shrinkage method,utilizing tannic acid-carbon nanotubes(TA@CNTs)as reinforcing units and a Ca^(2+)crosslinking strategy.The enhanced interfacial networks consisting of PVA crystalline domains,hydrogen bonding,and metal coordination endowed the composite hydrogel with a high mechanical strength,excellent flexibility,and fracture toughness,accompanied by a significant increase in crystallinity.The tensile strength and fracture toughness of the composite hydrogel reached up to about 7.0 MPa and 17.0MJ/m^(3),which were roughly 8 and 10 times higher than those of neat PVA hydrogel,respectively.The composite hydrogel demonstrated good cytocompatibility,significantly addressing the challenge of balancing structural reinforcement with biosafety in hydrogels.This methodology establishes a rational design for fabricating mechanically robust yet tough PVA hydrogels for biomedical applications.展开更多
In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Bas...In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Based on this novel approach,Al_(2)O_(3)powder was coated with a homogeneous layer of amorphous Y2O3,with the coated AI2O3 powder found to make the microstructure of 3D printed Al_(2)O_(3) ceramic more uniform and refined,as compared with the conventional mechanical mixing(MM)of Al_(2)O_(3) and Y_(2)O_(3) powders.The grain size of Al_(2)O_(3) in Sample CP is 64.44%and 51.43%lower than those in the monolithic Al_(2)O_(3) ceramic and Sample MM,respectively.Sample CP has the highest flexural strength of 455.37±32.17 MPa,which is 14.85%and 25.45%higher than those of Samples MM and AL,respectively;also Sample CP has the highest Weibull modulus of 16.88 among the three kinds of samples.Moreover,the fine grained Sample CP has a close thermal conductivity to the coarse grained Sample MM because of the changes in morphology of Y_(3)Al_(5)O_(12) phase from semi-connected(Sample MM)to isolated(Sample CP).Finally,specially designed fin-type Al_(2)O_(3) ceramic heat sinks were successfully fabricated via the novel integrated process,which has been proven to be an effective method for fabricating complex-shaped Al_(2)O_(3) ceramic components with enhanced flexural strength and reliability.展开更多
Let T be a bounded linear operator on a complex Hilbert space H. In this paper we introduce a new class denoted by l-＊-A, of operators satisfying T＊｜T2｜T≥ T＊｜T＊｜2T, and we prove the basic properties of these ...Let T be a bounded linear operator on a complex Hilbert space H. In this paper we introduce a new class denoted by l-＊-A, of operators satisfying T＊｜T2｜T≥ T＊｜T＊｜2T, and we prove the basic properties of these operators. Using these results, we also prove that if T or T＊ ∈l-＊-A, then w（f（T）） = f（w（T））, σea（f（T）） = f（σea（T）） for every f C H（σ（T））, where g（σ（T）） denotes the set of all analytic functions on an open neighborhood of σ（T）.展开更多
基金financially supported by the China Postdoctoral Science Foundation(No.2024M751205)the Natural Science Foundation of Jiangsu Province(JSNSF)(No.BK20230694)。
文摘Poly(vinyl alcohol)(PVA)hydrogels have garnered significant attention for tissue engineering,wound dressing,and electronic skin sensing applications.However,their poor mechanical performance severely restricts their multifunctional application in many scenarios.To address this limitation,PVA/tannic acid(TA)@carbon nanotubes(PVA/TA@CNTs)composite hydrogels with triple crosslinking networks were prepared through freezing-thawing and the solvent-induced shrinkage method,utilizing tannic acid-carbon nanotubes(TA@CNTs)as reinforcing units and a Ca^(2+)crosslinking strategy.The enhanced interfacial networks consisting of PVA crystalline domains,hydrogen bonding,and metal coordination endowed the composite hydrogel with a high mechanical strength,excellent flexibility,and fracture toughness,accompanied by a significant increase in crystallinity.The tensile strength and fracture toughness of the composite hydrogel reached up to about 7.0 MPa and 17.0MJ/m^(3),which were roughly 8 and 10 times higher than those of neat PVA hydrogel,respectively.The composite hydrogel demonstrated good cytocompatibility,significantly addressing the challenge of balancing structural reinforcement with biosafety in hydrogels.This methodology establishes a rational design for fabricating mechanically robust yet tough PVA hydrogels for biomedical applications.
基金supported by the Local Innovative and Research Team Project of Guangdong Province(Grant No.2017BT01C169)the Opening Project of State Key Laboratory of Green Building Materials(Grant No.2019GBM03)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2020A1515010004)the Natural Science Foundation of Guangdong Province(Grant No.2018A030313353)the Science and Technology Program of Guangzhou(Grant No.201904010357).
文摘In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Based on this novel approach,Al_(2)O_(3)powder was coated with a homogeneous layer of amorphous Y2O3,with the coated AI2O3 powder found to make the microstructure of 3D printed Al_(2)O_(3) ceramic more uniform and refined,as compared with the conventional mechanical mixing(MM)of Al_(2)O_(3) and Y_(2)O_(3) powders.The grain size of Al_(2)O_(3) in Sample CP is 64.44%and 51.43%lower than those in the monolithic Al_(2)O_(3) ceramic and Sample MM,respectively.Sample CP has the highest flexural strength of 455.37±32.17 MPa,which is 14.85%and 25.45%higher than those of Samples MM and AL,respectively;also Sample CP has the highest Weibull modulus of 16.88 among the three kinds of samples.Moreover,the fine grained Sample CP has a close thermal conductivity to the coarse grained Sample MM because of the changes in morphology of Y_(3)Al_(5)O_(12) phase from semi-connected(Sample MM)to isolated(Sample CP).Finally,specially designed fin-type Al_(2)O_(3) ceramic heat sinks were successfully fabricated via the novel integrated process,which has been proven to be an effective method for fabricating complex-shaped Al_(2)O_(3) ceramic components with enhanced flexural strength and reliability.
基金Supported by Science Foundation of Ministry of Education of China (Grant No.208081)
文摘Let T be a bounded linear operator on a complex Hilbert space H. In this paper we introduce a new class denoted by l-＊-A, of operators satisfying T＊｜T2｜T≥ T＊｜T＊｜2T, and we prove the basic properties of these operators. Using these results, we also prove that if T or T＊ ∈l-＊-A, then w（f（T）） = f（w（T））, σea（f（T）） = f（σea（T）） for every f C H（σ（T））, where g（σ（T）） denotes the set of all analytic functions on an open neighborhood of σ（T）.
