摘要 :
The graphite was modified using pitch through dynamical melt-carbonization, and the effects of modification temperature and the amount of pitch on the characteristics of graphite were investigated. The structure and characteristic...
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The graphite was modified using pitch through dynamical melt-carbonization, and the effects of modification temperature and the amount of pitch on the characteristics of graphite were investigated. The structure and characteristics of the graphite were determined by X-ray diffractometry(XRD), scanning electron microscopy(SEM), particle size analysis and electrochemical measurements. The results show that the modified graphite has a disordered carbon/graphite composite structure, larger average particle diameter, greater tap density, and better electrochemical characteristics than the untreated graphite. The sample coated with 10% pitch dynamical melt-carbonized at 400℃ for 3 h and heat-treated at 850℃ for 2 h has better electrochemical performances with a reversible capacity of 360.5 mA·h/g, a irreversible capacity of 41.0 mAh/g, and an initial coulombic efficiency of 89.8% compared with natural graphite and disordered carbon. The cycling stability of the Li/C cell with modified graphite as anodes is improved, and its capacity retention ratio at the 30th cycle is up to 94.37%.
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摘要 :
Analyses the errors of new parallel machine tools and presents a structural scheme for feedback compensati- on of machine tools to eliminate these errors, the theory behind and the relation between direction consine of normal vect...
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Analyses the errors of new parallel machine tools and presents a structural scheme for feedback compensati- on of machine tools to eliminate these errors, the theory behind and the relation between direction consine of normal vector of the workpiece surface and the rotation angles α,β,γ of the cutter head.
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摘要 :
Presents an inverse error estimation method for deriving errors of links from cutter head errors to overcome the difficulty in obtaining analytic solutions for new type of machine tools due to the multi-solution of direct kinemati...
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Presents an inverse error estimation method for deriving errors of links from cutter head errors to overcome the difficulty in obtaining analytic solutions for new type of machine tools due to the multi-solution of direct kinematics so that the total dimension chain tolerance of machine tool inks can be determined by Monte-Carlo random simulation for a certain spindle dimension of the machine tool and the precision requirement specified, and the method of dimen- sional tolerance allocation developed by analysing the elements of machine tool links and the combination of machine tool precision with actual dimensional tolerance for justification of tolerance deign for this kind of machine tools.
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