茶碱分子印迹PDVB-SO3H/PDVB IPN的合成及热力学性能研究

以茶碱为摸板分子，采用顺序聚合法，合成了分子印迹的大孔磺化聚二乙烯基苯，聚二乙烯基苯互穿聚合物网络（PDVB—SO3H／PDVB IPN），测定了IPN的结构和热力学性能。结果表明，制备的分子印迹聚合物对印迹分子茶碱具有较好吸附作用，且能保持第一网的树脂粒径。通过热力学性能研究，讨论了IPN吸附水溶液中茶碱的机理。     

Metabolic power and energy expenditure in an international men’s hockey tournament

The purpose of this study was to ascertain the typical metabolic power characteristics of elite men’s hockey, and whether changes occur within matches and throughout an international tournament. National team players (n = 16), divided into 3 positional groups (strikers, midfielders, defenders), wore Global Positioning System devices in 6 matches. Energetic (metabolic power, energy expenditure) and displacement (distance, speed, acceleration) variables were determined, and intensity was classified utilising speed, acceleration and metabolic power thresholds. Midfielder’s average metabolic power (11.8 ± 1.0 W · kg^?1) was similar to strikers (11.1 ± 1.3 W · kg^?1) and higher than defenders (10.8 ± 1.2 W · kg^?1, P = 0.001). Strikers (29.71 ± 3.39 kJ · kg^?1) expended less energy than midfielders (32.18 ± 2.67 kJ · kg^?1, P = 0.014) and defenders (33.23 ± 3.96 kJ · kg^?1, P < 0.001). Energetic variables did not change between halves or across matches. Across all positions, over 45% of energy expenditure was at high intensity (>20 W · kg^?1). International hockey matches are intense and highly intermittent; however, intensity is maintained throughout matches and over a tournament. In isolation, displacement measures underestimate the amount of high-intensity activity, whereas the integration of instantaneous speed and acceleration provides a more comprehensive assessment of the demands for variable-speed activity typically occurring in hockey matches.