Strontium titanate(SrTiO3) submicron-fibers with perovskite structure were successfully synthesized by electrospinning method. The nanomechanical properties of synthesized SrTiO3were investigated by the novel amplitud...Strontium titanate(SrTiO3) submicron-fibers with perovskite structure were successfully synthesized by electrospinning method. The nanomechanical properties of synthesized SrTiO3were investigated by the novel amplitude modulation-frequency modulation(AM-FM) method based on atomic force microscope and nanoindentation technique. The results of AM-FM show that the resonant frequency of SrTiO3submicron-fiber is lower than that of the Si substrate, which indicates that the Young’s modulus of SrTiO3submicron-fiber is smaller than that of Si substrate in the range of 105-125 GPa. Nanoindentation further confirmed the results, showing a value of 104 ± 17 GPa. The atomic force microscope-based AM-FM provides us a new way to study the mechanical performance of low dimensional materials.展开更多
采用静电纺丝技术制备出几种不同直径的亚微米纤维多孔材料（纤维直径分别为0.52μm,0.63μm和0.65μm）,通过傅里叶变换红外光谱测试了各材料的红外透过率;根据实验测试数据,基于Mie散射理论、Subtractive Kramers-Kronig（SKK）关系式...采用静电纺丝技术制备出几种不同直径的亚微米纤维多孔材料（纤维直径分别为0.52μm,0.63μm和0.65μm）,通过傅里叶变换红外光谱测试了各材料的红外透过率;根据实验测试数据,基于Mie散射理论、Subtractive Kramers-Kronig（SKK）关系式和Beer定律,计算了亚微米纤维多孔材料的复折射率和辐射热导率,研究了纤维直径对材料衰减系数和辐射热导率的影响,并以最小辐射热导率为目标对纤维直径进行了优化。结果表明,在300K温度下,对于纤维体积分数为0.03的多孔材料,直径为2.0μm时辐射热导率最小（0.292 m W/（m·K））,较0.52～0.65μm（实验条件）的辐射热导率降低了约25%。展开更多
Vinyl ester (VE) resin inherently has intrinsic brittleness due to its high cross-link density. To improve mechanical performance, micro/nano fillers are widely used to modify this matrix. In present study, glass fibe...Vinyl ester (VE) resin inherently has intrinsic brittleness due to its high cross-link density. To improve mechanical performance, micro/nano fillers are widely used to modify this matrix. In present study, glass fiber in submicron scale at low contents was added into VE to prepare submicron composite (sMC). The impact resistance of un-notched sMC degraded with the increase of sGF content while that of notched-sMC remained the unchanged. Flexural properties of sMCs also were the same with that of neat resin. The results of Dynamic mechanical analysis (DMA) test showed the slight increase of storage modulus and the decrease of tan delta value in the case of sMC compared to those of un-filled matrix. However, the Mode I fracture toughness of sMC improved up to 26% and 61% corresponding to 0.3 and 0.6 wt% glass fiber used. The compact tension sample test suggests that there is the delay of crack propagation under tensile cyclic load in resin reinforced by submicron glass fiber. The number of failure cycle enlarged proportionally with the increment of sGF content in matrix.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.11627801,11372268,11502225,and 51375017)
文摘Strontium titanate(SrTiO3) submicron-fibers with perovskite structure were successfully synthesized by electrospinning method. The nanomechanical properties of synthesized SrTiO3were investigated by the novel amplitude modulation-frequency modulation(AM-FM) method based on atomic force microscope and nanoindentation technique. The results of AM-FM show that the resonant frequency of SrTiO3submicron-fiber is lower than that of the Si substrate, which indicates that the Young’s modulus of SrTiO3submicron-fiber is smaller than that of Si substrate in the range of 105-125 GPa. Nanoindentation further confirmed the results, showing a value of 104 ± 17 GPa. The atomic force microscope-based AM-FM provides us a new way to study the mechanical performance of low dimensional materials.
文摘采用静电纺丝技术制备出几种不同直径的亚微米纤维多孔材料（纤维直径分别为0.52μm,0.63μm和0.65μm）,通过傅里叶变换红外光谱测试了各材料的红外透过率;根据实验测试数据,基于Mie散射理论、Subtractive Kramers-Kronig（SKK）关系式和Beer定律,计算了亚微米纤维多孔材料的复折射率和辐射热导率,研究了纤维直径对材料衰减系数和辐射热导率的影响,并以最小辐射热导率为目标对纤维直径进行了优化。结果表明,在300K温度下,对于纤维体积分数为0.03的多孔材料,直径为2.0μm时辐射热导率最小（0.292 m W/（m·K））,较0.52～0.65μm（实验条件）的辐射热导率降低了约25%。
文摘Vinyl ester (VE) resin inherently has intrinsic brittleness due to its high cross-link density. To improve mechanical performance, micro/nano fillers are widely used to modify this matrix. In present study, glass fiber in submicron scale at low contents was added into VE to prepare submicron composite (sMC). The impact resistance of un-notched sMC degraded with the increase of sGF content while that of notched-sMC remained the unchanged. Flexural properties of sMCs also were the same with that of neat resin. The results of Dynamic mechanical analysis (DMA) test showed the slight increase of storage modulus and the decrease of tan delta value in the case of sMC compared to those of un-filled matrix. However, the Mode I fracture toughness of sMC improved up to 26% and 61% corresponding to 0.3 and 0.6 wt% glass fiber used. The compact tension sample test suggests that there is the delay of crack propagation under tensile cyclic load in resin reinforced by submicron glass fiber. The number of failure cycle enlarged proportionally with the increment of sGF content in matrix.
