A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the a...A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.展开更多
In this paper we study the C3 compactness for minimal submanifolds in the unit sphere. We obtain two compactness theorems. As an application, we prove that there is a positive number δ(n), such that if the square of ...In this paper we study the C3 compactness for minimal submanifolds in the unit sphere. We obtain two compactness theorems. As an application, we prove that there is a positive number δ(n), such that if the square of the length of the second fundamental form of a minimal subrnanifold in the unit sphere is less than 2n/3+δ(n), it must be totally geodesic or diffeomorphic to a Veronese surface.展开更多
基金Project(2007BAE12B00) supported by the National Key Technology R&D Program of ChinaProject(50974136) supported by the National Natural Science Foundation of China
文摘A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in both capacitor and battery with a high reversible capacity of 306.6 mA·h/g(0.2C) in the half-cell,along with a capacitance of 25.8 F/g in the capacitor when an optimum ratio of carbonaceous mesophase spherules to active carbon is adopted.The composite also shows a favorable rate performance and good cycle ability.A working model of this anode in super lithium ion capacitors was established.
基金Supported by the National Natural Scieuce Foundation of China(19971081)
文摘In this paper we study the C3 compactness for minimal submanifolds in the unit sphere. We obtain two compactness theorems. As an application, we prove that there is a positive number δ(n), such that if the square of the length of the second fundamental form of a minimal subrnanifold in the unit sphere is less than 2n/3+δ(n), it must be totally geodesic or diffeomorphic to a Veronese surface.
