Si-Al分子筛催化2,5-二甲基-2,5-己二醇水解制备2,5-二甲基-2,4-己二烯

2,5-二甲基-2,5-己二醇在Si-Al分子筛催化剂的作用下一步完成脱水和异构化反应,得到2,5-二甲基-2,4-己二烯,反应在常压,200～250℃条件下进行2,5-二甲基-2,5-己二醇的转化率为100％,2,5-二甲基-2,4-己二烯的选择性为87％。     

论暑期集训期间运动员的补液问题

大运会集训多集中在炎热的暑期进行,运动员必然面临因大量出汗而导致体液大量流失的问题.本文探讨运动时脱水的机理、症状和危害,以及在暑期集训中教练员如何科学地对运动员进行补液,使运动员的运动能力尽快得到恢复和提高,以提高运动员的竞技能力和运动成绩.     

Relationship between physiological parameters and performance during a half-ironman triathlon in the heat

Abstract

Triathlon is a popular outdoor endurance sport performed under a variety of environmental conditions. The aim of this study was to assess physiological variables before and after a half-ironman triathlon in the heat and to analyse their relationship with performance. Thirty-four well-trained triathletes completed a half-ironman triathlon in a mean dry temperature of 29 ± 3ºC. Before and within 1 min after the end of the race, body mass, core temperature, maximal jump height and venous blood samples were obtained. Mean race time was 315 ± 40 min, with swimming (11 ± 1%), cycling (49 ± 2%) and running (40 ± 3%) representing different amounts of the total race time. At the end of the competition, body mass changed by ?3.8 ± 1.6% and the change in body mass correlated positively with race time (r = 0.64; P < 0.001). Core temperature increased from 37.5 ± 0.6ºC to 38.8 ± 0.7ºC (P < 0.001) and post-race core temperature correlated negatively with race time (r = ?0.47; P = 0.007). Race time correlated positively with the decrease in jump height (r = 0.38; P = 0.043), post-race serum creatine kinase (r = 0.55; P = 0.001) and myoglobin concentrations (r = 0.39; P = 0.022). In a half-ironman triathlon in the heat, greater reductions in body mass and higher post-competition core temperatures were present in faster triathletes. In contrast, slower triathletes presented higher levels of muscle damage and decreased muscle performance.     

空气气氛中滑石的热分解动力学实验研究

含水矿物的热分解动力学研究对于了解俯冲带中-深源地震的成因机制具有重要意义.本文用综合热分析仪(TG-DSC)研究滑石在动态空气气氛下的热分解过程,利用热重(TG)数据对滑石的热分解动力学进行分析.利用Friedman法和FWO法,分别计算滑石热分解过程中的表观活化能E_{a和指前因子A,并以Friedman法求得的活化能为初始值,通过非线性回归拟合得到热分解过程最可能的反应机理和动力学参数.研究结果表明,滑石在830~1 050 ℃内发生热分解,此过程为n级反应,表观活化能Ea为344.2 kJ/mol,指前因子A为4.9E12 s^-1.}     

论民族体育的凝聚与交往功能

章从社会学的角度出发。全面论述了云南少数民族体育活动的开展．对改善民族关系，促进民族兴旺，达到民族凝聚力等方面的作用。     

消炎利胆片中脱水穿心莲内酯的快速测定

采用高效液相色谱法测定消炎利胆片中脱水穿心莲内酯的含量。采用Hyporsic. ODSC18色谱柱;甲醇     

许昌市污水处理工艺初探

随着工业化及城市化的迅速发展,水环境污染问题日趋严重,不但严重危害着人民群众的身心健康,而且已经成为国民经济发展和改革开放的主要制约因素.为此,针对许昌市污水处理技术进行研究,探讨水污染治理的有效途径.     

实验室制备无水醋酸铅的一种简易方法

以甲苯为脱水剂，制备无水醋酸铅实验室制法。该方法操作简便，反应时间短，得到的无水醋酸铅的收率也较高。     

Effect of acute L-Alanyl-L-Glutamine and electrolyte ingestion on cognitive function and reaction time following endurance exercise

The purpose of this study was to examine the effect of the L-Alanyl-L-Glutamine dipeptide (AG) on cognitive function and reaction time (RT) following endurance exercise. Twelve male endurance athletes (23.5 ± 3.7 y; 175.5 ± 5.4 cm; 70.7 ± 7.6 kg) performed four trials, each consisting of running on a treadmill at 70% of VO₂max for 1h, then at 90% of VO₂max until exhaustion. One trial consisted of no hydration (DHY), another required ingestion of only a sports electrolyte drink (ED) and two trials required ingestion of a low dose (LD; 300 mg·500 ml^?1) and high dose (HD) of AG (1 g·500ml^?1) added to the ED. Cognitive function and reaction tests were administered pre- and post-exercise. Magnitude based inferences were used to analyze ? cognitive function and ? reaction test data. Results indicated that DHY had a possible negative effect on number of hits in a 60-sec reaction test compared to LD and HD, while ED appeared to have a negative effect compared to HD. Analysis of lower body quickness indicated that LD and HD were likely improved in comparison to DHY. Performance on the serial subtraction test appeared to be possibly better in ED than DHY, while other comparisons between groups regarding cognitive function were unclear. In conclusion, rehydrating with AG during submaximal exercise may maintain or enhance subsequent RT in upper and lower body activities compared to DHY. These same effects were not apparent when participants consumed ED.