Carbon fiber composites have high strength, high stiffness and light weight characteristics to apply to many fields, such as leisure, energy and transportation industries. The CFRP （carbon fiber reinforced polymers/p...Carbon fiber composites have high strength, high stiffness and light weight characteristics to apply to many fields, such as leisure, energy and transportation industries. The CFRP （carbon fiber reinforced polymers/plastics） composites made of carbon fibers as reinforcement and epoxy resins as matrix were prepared by drum winding process. Various parameters such as molding temperature, molding pressure and pressing time were selected as the pre-pregs were laminated to be the CFRP. The effects of fabricating parameters which affected the mechanical properties of CFRPs were analyzed by Taguchi method in this study. The results showed that molding temperature was the main factor to influence the mechanical properties of composites.展开更多
Material functionalities strongly depend on the stoichiometry,crystal structure,and homogeneity.Here we demonstrate an approach of amorphous nonstoichiometric inhomogeneous oxides to realize tunable ferromagnetism and...Material functionalities strongly depend on the stoichiometry,crystal structure,and homogeneity.Here we demonstrate an approach of amorphous nonstoichiometric inhomogeneous oxides to realize tunable ferromagnetism and electrical transport at room temperature.In order to verify the origin of the ferromagnetism,we employed a series of structural,chemical,and electronic state characterizations.Combined with electron microscopy and transport measurements,synchrotron-based grazing incident wide angle X-ray scattering,soft X-ray absorption and circular dichroism clearly reveal that the roomtemperature ferromagnetism originates from the In0.23Co0.77O1-v,amorphous phase with a large tunable range of oxygen vacancies.The room-temperature ferromagnetism is tunable from a high saturation magnetization of 500 emu cm-3 to below 25 emu cm-3,with the evolving electrical resistivity from5×103μΩ cm to above 2.5×105 μΩ cm.Inhomogeneous nano-crystallization emerges with decreasing oxygen vacancies,driving the system towards non-ferromagnetism and insulating regime.Our work unfolds the novel functionalities of amorphous nonstoichiometric inhomogeneous oxides,which opens up new opportunities for developing spintronic materials with superior magnetic and transport properties.展开更多
The structural, electronic and magnetic properties of La0.55Ca0.45MnO3 were measured. A rapid change of lattice parameters appeared around 190 K associated with the az2 orbital ordering and charge ordering （CO） stat...The structural, electronic and magnetic properties of La0.55Ca0.45MnO3 were measured. A rapid change of lattice parameters appeared around 190 K associated with the az2 orbital ordering and charge ordering （CO） states that were reflected by both magnetization and resistivity. Great difference of magnetizations between the field-cooling （FC） and zero-field-cooling （ZFC） modes below the charge ordering temperature Too in high magnetic field （H〉4 T） was clearly seen. A field of 5 T （threshold field） is sufficient to completely destroy the antiferromagnetic （AFM） CO state for FC mode in magnetization while it is not the case for ZFC mode. A much larger field （larger than 10 T from ZFC resistivity data） is needed to destroy the CO state for ZFC mode. This could be explained by the coexistence and transformation of two phases reported by Huang et al. For ZFC mode, with increasing H, Tco gradually moves to low temperature regime and the relationship between the critical field Hc （0） to destroy CO state and Tco conforms to a power law Hc = Hc（0）（1 - T/Tco（0））^γ, where Hc （0） is the critical field to destroy the CO state at 0 K, and Too （0） is the CO temperature in zero field.展开更多
文摘Carbon fiber composites have high strength, high stiffness and light weight characteristics to apply to many fields, such as leisure, energy and transportation industries. The CFRP （carbon fiber reinforced polymers/plastics） composites made of carbon fibers as reinforcement and epoxy resins as matrix were prepared by drum winding process. Various parameters such as molding temperature, molding pressure and pressing time were selected as the pre-pregs were laminated to be the CFRP. The effects of fabricating parameters which affected the mechanical properties of CFRPs were analyzed by Taguchi method in this study. The results showed that molding temperature was the main factor to influence the mechanical properties of composites.
基金supported by the National Natural Science Foundation of China (11434006, 11774199, and 51871112)the National Basic Research Program of China (2015CB921502)+1 种基金the 111 Project B13029supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DEAC02-76SF00515。
文摘Material functionalities strongly depend on the stoichiometry,crystal structure,and homogeneity.Here we demonstrate an approach of amorphous nonstoichiometric inhomogeneous oxides to realize tunable ferromagnetism and electrical transport at room temperature.In order to verify the origin of the ferromagnetism,we employed a series of structural,chemical,and electronic state characterizations.Combined with electron microscopy and transport measurements,synchrotron-based grazing incident wide angle X-ray scattering,soft X-ray absorption and circular dichroism clearly reveal that the roomtemperature ferromagnetism originates from the In0.23Co0.77O1-v,amorphous phase with a large tunable range of oxygen vacancies.The room-temperature ferromagnetism is tunable from a high saturation magnetization of 500 emu cm-3 to below 25 emu cm-3,with the evolving electrical resistivity from5×103μΩ cm to above 2.5×105 μΩ cm.Inhomogeneous nano-crystallization emerges with decreasing oxygen vacancies,driving the system towards non-ferromagnetism and insulating regime.Our work unfolds the novel functionalities of amorphous nonstoichiometric inhomogeneous oxides,which opens up new opportunities for developing spintronic materials with superior magnetic and transport properties.
基金supported by the National Natural Science Foundation of China (Grant No. 50772111)the 211 Project of Anhui University (Grant No. 06130221)
文摘The structural, electronic and magnetic properties of La0.55Ca0.45MnO3 were measured. A rapid change of lattice parameters appeared around 190 K associated with the az2 orbital ordering and charge ordering （CO） states that were reflected by both magnetization and resistivity. Great difference of magnetizations between the field-cooling （FC） and zero-field-cooling （ZFC） modes below the charge ordering temperature Too in high magnetic field （H〉4 T） was clearly seen. A field of 5 T （threshold field） is sufficient to completely destroy the antiferromagnetic （AFM） CO state for FC mode in magnetization while it is not the case for ZFC mode. A much larger field （larger than 10 T from ZFC resistivity data） is needed to destroy the CO state for ZFC mode. This could be explained by the coexistence and transformation of two phases reported by Huang et al. For ZFC mode, with increasing H, Tco gradually moves to low temperature regime and the relationship between the critical field Hc （0） to destroy CO state and Tco conforms to a power law Hc = Hc（0）（1 - T/Tco（0））^γ, where Hc （0） is the critical field to destroy the CO state at 0 K, and Too （0） is the CO temperature in zero field.
