A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubula...A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.展开更多
根据宝钢高速运动薄钢板激光加工的实际需要,本项目研制出新型脉冲调Q N d:YA G激光打孔和打标两用激光加工系统所用的计算机操作系统,可以产生频率、幅值、脉冲宽度、脉冲组数等均可自由调整的控制脉冲信号,获得满足现场要求的打孔和...根据宝钢高速运动薄钢板激光加工的实际需要,本项目研制出新型脉冲调Q N d:YA G激光打孔和打标两用激光加工系统所用的计算机操作系统,可以产生频率、幅值、脉冲宽度、脉冲组数等均可自由调整的控制脉冲信号,获得满足现场要求的打孔和打标。展开更多
The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficien...The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.展开更多
Poly(lactic acid)(PLA) was blended with various polycaprolactone(PCL) components through the melt blending process for toughening modification on PLA.The tensile testing,scanning electron microscope(SEM) and different...Poly(lactic acid)(PLA) was blended with various polycaprolactone(PCL) components through the melt blending process for toughening modification on PLA.The tensile testing,scanning electron microscope(SEM) and differential scanning calorimetry(DSC) were implemented to analyze mechanical properties,disperse morphology,thermal properties and compatibility of composite materials,respectively.The shape memory performance of PCL/PLA composites was also investigated.The results showed that the elongation at break of composites increased by 10 and 15 times than pure PLA with adding 20% and30% by weight of PCL,and the yield strength retention rates were77% and 67%,respectively.The SEM showed that PCL/PLA composite was a semi-compatible system.PCL particles could be evenly dispersed in the PLA at 20% or 30% by weight PCL content,and the particle size was very small.DSC results showed a decline in Tg and Tm whereas an increase in Td with the addition of PCL.The addition of PCL could improve the shape memory performance of PLA.The shape memory performance was enhanced with the PCL content increase,but decreased with the tensile strain increase.The best temperature for shape recovery was between 60 and 70 ℃,and the shape memory performance remained 80% after 5 times recycle.展开更多
Disc-electrospinning using a disc as spinneret and a rotary drum as collector is a novel technology to prepare nanofiber which has been applied in tissue engineering scaffolds.In this study,nanofibrous mats with micro...Disc-electrospinning using a disc as spinneret and a rotary drum as collector is a novel technology to prepare nanofiber which has been applied in tissue engineering scaffolds.In this study,nanofibrous mats with micro-patterned structure were fabricated via disc-electrospinning.Poly( #-caprolactone)( PCL) was dissolved in trifluoroethanol( TFE) at various concentrations( 2%-7%)( w / v)for electrospinning and the applied voltage ranged from 40 to 70 kV.Scanning electron microscopy( SEM) was employed to observe the morphology of the nanofibrous scaffolds.SEM images illustrated that the nanofibers with beads formed micro-patterned structure such as triangles and other polygons.The average diameter of nanofibers presented various size with the concentration increased from 2% to 7%.The beads on the nanofibers constructed the vertexes of the polygons,while nanofibers bridged between adjacent vertexes.The concentration of solution and applied voltage may be two dominant factors to influence the topological structure of the nanofibrous scaffolds.Cells cultured on the micro-patterned scaffold spread along the edges of the polygons.The scaffold with patterned structure may have a promising application in tissue engineering.展开更多
Security protocols are the basis of many mobile communication systems,thus it is important to ensure protocol property correct. Using Protocol Composition Logic (PCL),this paper proves a Mobile IP (MIP) registration p...Security protocols are the basis of many mobile communication systems,thus it is important to ensure protocol property correct. Using Protocol Composition Logic (PCL),this paper proves a Mobile IP (MIP) registration protocol that is based on certificateless public key signature without pairing between home agent and foreign agent,which minimizes the registration time and cost as well as improves the security compared with the identity-based and certificate-based registration protocol. Analysis and proof shows that the proposed protocol provides users security and authentications,moreover,the anonymity property is proved correct.展开更多
为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,...为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,且当预拉伸的复合材料薄膜受到100 mW/cm^(2)强度的激光照射时,CB颗粒吸收激光光子而产生光热转换且由于各向异性链松弛和应变能释放,致使上层薄膜在受到激光照射时,结晶熔融发生形状记忆效应而收缩,与此同时下层薄膜仍然处于玻璃态,上层薄膜的收缩力使PCL/CB复合材料薄膜朝着激光照射方向发生弯曲变形。同时,弯曲角度可以通过薄膜预拉伸应变量、激光照射时间以及薄膜厚度3个参数进行调控;当预拉伸应变为300%、薄膜厚度为0.4 mm时,最大弯曲角为164°。这种具备局部可编程行为的PCL/CB复合薄膜可为光响应SMP的变形模式提供新思路。展开更多
基金Fundamental Research Funds for the Central UniversitiesNational Natural Science Foundation of China(No.31100682)
文摘A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.
基金National Natural Science Foundations of China(No.30970714,No.51103092)Natural Science Foundation of Jiangsu Province,China(No.BK2012634)+1 种基金College Natural Science Research Project of Jiangsu Province,China(No.12KJA430003)Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The mechanical properties and water solubility of electrospinning SF films limit their use as biomaterials. In order to develop a tissue engineering biomaterial with both satisfying biological properties and sufficient biomechanical properties,blended films composed of silk fibroin( SF) and poly( ε-caprolactone)( PCL) were fabricated by electrospinning in this study. Scanning electron microscope( SEM), X-ray diffraction( XRD),thermal analysis,Fourier transform-infrared( FT-IR),Raman spectra,mechanical testing,and water solubility were used to characterize the morphological, structural and mechanical properties of the blended electrospinning films. Results showed that the diameter of the blended fiber was distributed between 600 and1000 nm,and the fiber diameter increased as the PCL content increased. There is no obvious phase separation due to the similarity and intermiscibility,as well as the interactions( mainly hydrogen bonds), between the two polymers. Meanwhile, the secondary structures of SF changed from random coils and Silk I to Silk II because of the interactions between SF and PCL. For this reason,the tensile strength and elongation at break of the electrospinning films improved significantly,and the water solubility decreased. In conclusion,the blended electrospinning films fabricated in this study showed satisfying mechanical properties and water insolubilities,and they may be promising biomaterials for applications in tissue engineering for blood vessels,nerve conduits,tendons,ligaments and other tissues.
基金National Natural Science Foundation of China(No.51303085)Prospective Joint Research Project of Jiangsu Province,China(No.BY2015047-14)
文摘Poly(lactic acid)(PLA) was blended with various polycaprolactone(PCL) components through the melt blending process for toughening modification on PLA.The tensile testing,scanning electron microscope(SEM) and differential scanning calorimetry(DSC) were implemented to analyze mechanical properties,disperse morphology,thermal properties and compatibility of composite materials,respectively.The shape memory performance of PCL/PLA composites was also investigated.The results showed that the elongation at break of composites increased by 10 and 15 times than pure PLA with adding 20% and30% by weight of PCL,and the yield strength retention rates were77% and 67%,respectively.The SEM showed that PCL/PLA composite was a semi-compatible system.PCL particles could be evenly dispersed in the PLA at 20% or 30% by weight PCL content,and the particle size was very small.DSC results showed a decline in Tg and Tm whereas an increase in Td with the addition of PCL.The addition of PCL could improve the shape memory performance of PLA.The shape memory performance was enhanced with the PCL content increase,but decreased with the tensile strain increase.The best temperature for shape recovery was between 60 and 70 ℃,and the shape memory performance remained 80% after 5 times recycle.
基金National Natural Science Foundations of China，Science and Technology Comission of Shanghai Municipality,China，Ph.D.Programs Foundation of Ministry of Education of China
文摘Disc-electrospinning using a disc as spinneret and a rotary drum as collector is a novel technology to prepare nanofiber which has been applied in tissue engineering scaffolds.In this study,nanofibrous mats with micro-patterned structure were fabricated via disc-electrospinning.Poly( #-caprolactone)( PCL) was dissolved in trifluoroethanol( TFE) at various concentrations( 2%-7%)( w / v)for electrospinning and the applied voltage ranged from 40 to 70 kV.Scanning electron microscopy( SEM) was employed to observe the morphology of the nanofibrous scaffolds.SEM images illustrated that the nanofibers with beads formed micro-patterned structure such as triangles and other polygons.The average diameter of nanofibers presented various size with the concentration increased from 2% to 7%.The beads on the nanofibers constructed the vertexes of the polygons,while nanofibers bridged between adjacent vertexes.The concentration of solution and applied voltage may be two dominant factors to influence the topological structure of the nanofibrous scaffolds.Cells cultured on the micro-patterned scaffold spread along the edges of the polygons.The scaffold with patterned structure may have a promising application in tissue engineering.
基金Supported by the National Natural Science Foundation of China (No.60572147)State Key Laboratory Specific Foundation (ISN090307)the 111 Project (B08038)
文摘Security protocols are the basis of many mobile communication systems,thus it is important to ensure protocol property correct. Using Protocol Composition Logic (PCL),this paper proves a Mobile IP (MIP) registration protocol that is based on certificateless public key signature without pairing between home agent and foreign agent,which minimizes the registration time and cost as well as improves the security compared with the identity-based and certificate-based registration protocol. Analysis and proof shows that the proposed protocol provides users security and authentications,moreover,the anonymity property is proved correct.
文摘为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,且当预拉伸的复合材料薄膜受到100 mW/cm^(2)强度的激光照射时,CB颗粒吸收激光光子而产生光热转换且由于各向异性链松弛和应变能释放,致使上层薄膜在受到激光照射时,结晶熔融发生形状记忆效应而收缩,与此同时下层薄膜仍然处于玻璃态,上层薄膜的收缩力使PCL/CB复合材料薄膜朝着激光照射方向发生弯曲变形。同时,弯曲角度可以通过薄膜预拉伸应变量、激光照射时间以及薄膜厚度3个参数进行调控;当预拉伸应变为300%、薄膜厚度为0.4 mm时,最大弯曲角为164°。这种具备局部可编程行为的PCL/CB复合薄膜可为光响应SMP的变形模式提供新思路。
