ABSTRACT
Previous research on affordance perception has shown that elite athletes can relate the environmental features to their motor abilities to detect the opportunities for action. In playing badminton doubles, experienced players can often anticipate whether a flick serve will go out-of-bounds or not. A field study was performed to examine if such an ability was associated with a developed affordance perception. Twenty-two players with and without badminton playing experience were asked to play a receiver on court to judge without looking back whether a flick serve was out-of-bounds in both standing and retreating conditions. Forty flick serves were randomly delivered to either inner or outer rear corner of the receiver's box and land adjacent to the back service line. Each player's ability to reach high and retreat backward with a racquet was assessed on court. The results showed that predictions were better in the inner direction than the outer direction, but experienced players were more sensitive and conservative overall. Playing experience appeared to be a consistent predictor for judgment accuracy. In identifying the affordance information that could have been utilized by players for accurate predictions, only experienced players demonstrated the ability to utilize both body-scaled and action-scaled affordances effectively and reliably for better predictions in both standing and retreating conditions.
ABSTRACT
A facile and environmentally friendly fabrication is proposed to prepare nitrogen-doped hierarchical porous activated carbon via normal-pressure popping, one-pot activation and nitrogen-doping process. The method adopts paddy as carbon precursor, KHCO3 and dicyandiamide as the safe activating agent and nitrogen dopant. The as-prepared activated carbon presents a large specific surface area of 3025 m2·g-1 resulting from the synergistic effect of KHCO3 and dicyandiamide. As an electrode material, it shows a maximum specific capacitance of 417 F·g-1 at a current density of 1 A·g-1 and very good rate performance. Furthermore, the assembled symmetric supercapacitor presents a large specific capacitance of 314.6 F·g-1 and a high energy density of 15.7 Wh·Kg-1 at 1 A·g-1, maintaining 14.4 Wh·Kg-1 even at 20 A·g-1 with the energy density retention of 91.7%. This research demonstrates that nitrogen-doped hierarchical porous activated carbon derived from paddy has a significant potential for developing a high-performance renewable supercapacitor and provides a new route for economical and large-scale production in supercapacitor application.
