Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of R...Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of Rest Charge Energy at the location of its charge since r = 0 gives , which is clearly not possible. Since the electron has no internal structure, equating its Rest Mass Energy to its Rest Charge Energy, we calculate the electron to be a sphere of radius 4.68 × 10<sup>-</sup><sup>16</sup> meters. We calculate the Electric Field at the surface of the electron due to its charge and the Repulsive Force two electrons in proximity exert on each other.展开更多
目的:探讨不同体重指数(body mass index,BMI)青年男性静息能量消耗(resting energy expenditure,REE)的特点,比较常见静息代谢率(resting metabolic rate,RMR)预测方程与间接测热法的差异。方法:以2017年12月至2021年6月于北京大学第...目的:探讨不同体重指数(body mass index,BMI)青年男性静息能量消耗(resting energy expenditure,REE)的特点,比较常见静息代谢率(resting metabolic rate,RMR)预测方程与间接测热法的差异。方法:以2017年12月至2021年6月于北京大学第三医院运动医学科进行静息代谢测试的30名青年男性为研究对象,采用间接测热法测定RMR,采用生物电阻抗法测定体成分。分析研究对象REE的特点,并与11个常见预测方程的推算值进行比较,通过配对t检验和组内相关系数(intra-class correlation coefficient,ICC)评估两者差异。结果:30名青年男性的平均年龄为(26.93±4.16)岁,整体RMR为(1960.17±463.11)kcal/d(1 kcal=4.1868 kJ),其中BMI正常者的RMR为(1744.33±249.62)kcal/d,显著低于超重或肥胖者[(2104.06±520.32)kcal/d](P<0.01),但体质量校正后,BMI正常者的RMR显著高于超重或肥胖者[(24.02±2.61)kcal/(kg·d)vs.(19.98±4.38)kcal/(kg·d),P<0.01];不同BMI受试者的RMR与体质量、脂肪量、去脂体重、体表面积、细胞外液呈显著正相关(P均<0.05)。11个预测方程的预测值与实测值的一致性均不佳(ICC均<0.75),其中,超重或肥胖青年男性采用世界卫生组织(World Health Organization,WHO)推荐使用的RMR预测方程的预测值与实测值的一致性相对较高(ICC=0.547,P<0.01)。结论:不同BMI青年男性的RMR存在显著差异,超重或肥胖者要考虑体质量矫正后的RMR情况。不同预测方程的预测值与RMR的实测值一致性较差,建议通过间接测热法准确测定RMR。对于超重和肥胖的青年男性可以考虑采用WHO推荐使用的预测方程计算RMR,但有必要建立适用于不同BMI人群的RMR预测方程。展开更多
文摘Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of Rest Charge Energy at the location of its charge since r = 0 gives , which is clearly not possible. Since the electron has no internal structure, equating its Rest Mass Energy to its Rest Charge Energy, we calculate the electron to be a sphere of radius 4.68 × 10<sup>-</sup><sup>16</sup> meters. We calculate the Electric Field at the surface of the electron due to its charge and the Repulsive Force two electrons in proximity exert on each other.
文摘目的:探讨不同体重指数(body mass index,BMI)青年男性静息能量消耗(resting energy expenditure,REE)的特点,比较常见静息代谢率(resting metabolic rate,RMR)预测方程与间接测热法的差异。方法:以2017年12月至2021年6月于北京大学第三医院运动医学科进行静息代谢测试的30名青年男性为研究对象,采用间接测热法测定RMR,采用生物电阻抗法测定体成分。分析研究对象REE的特点,并与11个常见预测方程的推算值进行比较,通过配对t检验和组内相关系数(intra-class correlation coefficient,ICC)评估两者差异。结果:30名青年男性的平均年龄为(26.93±4.16)岁,整体RMR为(1960.17±463.11)kcal/d(1 kcal=4.1868 kJ),其中BMI正常者的RMR为(1744.33±249.62)kcal/d,显著低于超重或肥胖者[(2104.06±520.32)kcal/d](P<0.01),但体质量校正后,BMI正常者的RMR显著高于超重或肥胖者[(24.02±2.61)kcal/(kg·d)vs.(19.98±4.38)kcal/(kg·d),P<0.01];不同BMI受试者的RMR与体质量、脂肪量、去脂体重、体表面积、细胞外液呈显著正相关(P均<0.05)。11个预测方程的预测值与实测值的一致性均不佳(ICC均<0.75),其中,超重或肥胖青年男性采用世界卫生组织(World Health Organization,WHO)推荐使用的RMR预测方程的预测值与实测值的一致性相对较高(ICC=0.547,P<0.01)。结论:不同BMI青年男性的RMR存在显著差异,超重或肥胖者要考虑体质量矫正后的RMR情况。不同预测方程的预测值与RMR的实测值一致性较差,建议通过间接测热法准确测定RMR。对于超重和肥胖的青年男性可以考虑采用WHO推荐使用的预测方程计算RMR,但有必要建立适用于不同BMI人群的RMR预测方程。
基金Supported by the National Basic Research Program of China under Grant No 2003CB716300, and the National Natural Science Foundation of China under Grant No 10121503.
