Low intrinsic conductivity and poor structural stability limit the application of Na 3 V 2 (PO 4 ) 3 (NVP). Herein, a strategy for the in situ synthesis of dandelion-shaped NVP based on cross-linked chitosan quaternary ammonium hydrogel (CHACC) and carbon nanotubes (CNTs) is proposed. CHACC and CNTs provide steric hindrance and avoid agglomeration of precursor particles. Notably, CHACC could be carbonized into a thin N−Cl codoped carbon coating, attaching to short CNTs fibers by electrostatic adsorption to construct the dandelion shape. The N−Cl codoped carbon coating delivers superior electronic conductivity and generates beneficial defects. DFT calculations are explored to investigate the influence of N−Cl codoping in the mixed carbon matrix. Significantly, triple conductive networks are successfully constructed by the dual-carbon resources. CNTs attached to the carbon coating connect with each other forms first network. Large-scale CNT network is generated through physical entanglement and bonding. CHACC provides additional conductive substrate after carbonizations. The unique triple networks supply stable carbon skeleton, alleviating the impact of current shock and increasing active sites. CHACC−CNTs-NVP submitted a value of 82.5 mAh g −1 at 80 C and remained at 61.9 mAh g −1 after 6000 cycles, corresponding to a low decay rate of 0.004% per cycle. Even at 120 C, it still releases 81.5 mAh g −1 .
Grinding chatter belongs to non-linear vibration, whose generation mechanism is complex. The eliminating and reducing of vibration are very difficult, which have been one of the hot and difficult problems at home and abroad. Power ultrasonic vibration honing is a special processing that adds secondary ultrasonic into traditional honing. Adding ultrasound not only superimposes high-frequency vibration components on the trajectories, which makes trajectories become very complex, but also makes high frequency ultrasonic vibration elements greatly influence the vibration trajectory of chatter, which makes the stability analysis of ultrasonic honing become more complex, so it is necessary to specially study in vibration trajectories of honing process. Taking axial ultrasonic vibration honing as an example, the paper respectively takes single wear debris, two adjacent wear debris, oilstone as study object to discuss on the variation rules of honing chatter vibration trajectory after adding ultrasonic, and obtains the following conclusions: adding ultrasonic can larger vibration trajectory for single wear debris or two adjacent wear debris on microscopic scales, on the view of macroscopic which is performed as honing depth of oilstone increasing; the effects of adding ultrasonic to chatter depend on the t value; through appropriately adjusting or selecting process parameters and structural ones, chatter can be completely avoided.
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