探讨60%THR运动强度下不同运动密度对青少年运动能耗与体质健康的影响。方法:将146名健康小学生随机分成低、中、高运动密度组和对照组,分别采用Polar Team OH1和Actigraph wGT3X-BT监测运动强度和运动能耗。结果:运动能耗建模后,时段...探讨60%THR运动强度下不同运动密度对青少年运动能耗与体质健康的影响。方法:将146名健康小学生随机分成低、中、高运动密度组和对照组,分别采用Polar Team OH1和Actigraph wGT3X-BT监测运动强度和运动能耗。结果:运动能耗建模后,时段以及时段与组别交互作用无统计学意义,运动能耗与组别交互作用有统计学意义;体质健康建模后,BMI变化、往返跑、50 m跑和坐位体前屈进步幅度组别主效应以及肺活量、跳绳进步幅度"组别×性别"的交互效应均有统计学意义,仰卧起坐组别主效应和"组别×性别"交互效应均无统计学意义。结论:60%THR运动强度、36%～74%运动密度的运动负荷是维持身体基本运动能力的最小阈值,55%～74%的运动密度是引起BMI下降的最小阈值并适宜发展女生跳绳能力,75%以上运动密度是健康促进效应和提高运动能力的价值阈。展开更多
The optimal performance of heat-driven binary separation processes with linear phenomenological heat transfer law(q∝△(T-1)) is analyzed by taking the processes as heat engines which work between high-and low-tempera...The optimal performance of heat-driven binary separation processes with linear phenomenological heat transfer law(q∝△(T-1)) is analyzed by taking the processes as heat engines which work between high-and low-temperature reservoirs and produce enthalpy and energy flows out of the system,and the temperatures of the heat reservoirs are assumed to be time-and space-variables.A numerical method is employed to solve convex optimization problem and Lagrangian function is employed to solve the average optimal control problem.The dimensionless entropy production rate coefficient and dimensionless enthalpy flow rate coefficient are adopted to indicate the major influence factors on the performance of the separation process,such as the properties of different materials and various separation requirements for the separation process.The dimensionless minimum average entropy production rate and dimensionless minimum average heat consumption of the heat-driven binary separation processes are obtained.The obtained results are compared with those obtained with the Newtonian heat transfer law(q∝△(T)).展开更多
文摘探讨60%THR运动强度下不同运动密度对青少年运动能耗与体质健康的影响。方法:将146名健康小学生随机分成低、中、高运动密度组和对照组,分别采用Polar Team OH1和Actigraph wGT3X-BT监测运动强度和运动能耗。结果:运动能耗建模后,时段以及时段与组别交互作用无统计学意义,运动能耗与组别交互作用有统计学意义;体质健康建模后,BMI变化、往返跑、50 m跑和坐位体前屈进步幅度组别主效应以及肺活量、跳绳进步幅度"组别×性别"的交互效应均有统计学意义,仰卧起坐组别主效应和"组别×性别"交互效应均无统计学意义。结论:60%THR运动强度、36%～74%运动密度的运动负荷是维持身体基本运动能力的最小阈值,55%～74%的运动密度是引起BMI下降的最小阈值并适宜发展女生跳绳能力,75%以上运动密度是健康促进效应和提高运动能力的价值阈。
基金Supported by the Program for New Century Excellent Talents of China (Grant No. NCET-04-1006)the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 200136)
文摘The optimal performance of heat-driven binary separation processes with linear phenomenological heat transfer law(q∝△(T-1)) is analyzed by taking the processes as heat engines which work between high-and low-temperature reservoirs and produce enthalpy and energy flows out of the system,and the temperatures of the heat reservoirs are assumed to be time-and space-variables.A numerical method is employed to solve convex optimization problem and Lagrangian function is employed to solve the average optimal control problem.The dimensionless entropy production rate coefficient and dimensionless enthalpy flow rate coefficient are adopted to indicate the major influence factors on the performance of the separation process,such as the properties of different materials and various separation requirements for the separation process.The dimensionless minimum average entropy production rate and dimensionless minimum average heat consumption of the heat-driven binary separation processes are obtained.The obtained results are compared with those obtained with the Newtonian heat transfer law(q∝△(T)).
