共查询到20条相似文献，搜索用时 109 毫秒
1.
以参加第十一届全运会的山东省男子曲棍球队8名运动员作为实验对象,对运动员运动过程中肌肉短时间持续用力的力量耐力机制进行对比实验研究.分别采用400米(速度耐力)和持续杠铃半蹲(力量耐力)两种不同的素质测试.通过两种测试后生化指标的分析对比,分析了力量耐力的形成机制. 相似文献
2.
采用AC-HVAF活性燃烧高速燃气喷涂设备在Q235钢表面喷涂WCp/(Co+Cr)复合材料涂层,应用光学金相显微镜分析涂层的显微组织,应用扫描电镜分析涂层断口形貌.结果表明,WCp/(Co+Cr)复合材料涂层组织致密均匀;涂层具有良好的耐磨性,其相对耐磨性比淬火回火态中碳45钢提高40倍. 相似文献
3.
本试验针对20CrMo低合金钢采用渗碳、渗硫处理,以提高20CrMo钢的表面耐磨性,运用金相显微镜,HMV-200型显微硬度计,JSM-5500LV扫描电子显微镜对渗层的形貌,相结构等进行分析,用MM-200快速磨损试验机和MH-2000磨损试验机进行摩擦磨损性能试验。 相似文献
4.
0 前言
镁合金重量轻、比强度高,弹性模量小、刚性好、抗震力强,抗电磁干扰及屏蔽性好,且有色泽鲜艳、美观等优点,从而在实际中被大量应用.但其防腐、耐磨性较差使其应用范围受到了限制.解决镁合金腐蚀和磨损问题是提高镁合金的使用寿命,拓宽镁合金的应用范围的关键问题,因此在实际应用中对它们进行必要的表面改性处理以增强其性能,成为必不可少的一环.
冷喷涂是一种新的表面改性处理方法.在实际操作中,冷喷涂能有效避免对镁合金基体进行热喷涂时,镁合金表面发生的强烈反应,这些反应会使镁合金表面发生相变、氧化、合金成分烧损、再结晶等现象.冷喷涂表面改性工艺可保持颗粒材料原有的性能.冷喷涂技术由于其特殊的喷涂特点和工艺成为喷涂领域的研究前沿技术.
本文以镁合金作为基体,对其使用冷喷涂技术制备表面改性涂层并进行研究. 相似文献
5.
6.
软玉名称的来历公元1863年,对传入欧洲的中国清代乾隆年间的玉器,法国地质矿物学家德木尔在用物理的方法分析时,将和田玉与翡翠相互刻划进行硬度对比测试。用翡翠可以在和田玉上刻划出痕迹,而用和田玉则不能在翡翠上刻划出痕迹,发现了翡翠的硬度大于和田玉。(用现代的手段测试,翡翠的对比硬度为莫氏6.75～7,和田玉的对比硬度为其氏6.5～6.9,也证实了翡翠的硬度稍大于和田玉)。德木尔因此把翡翠称 相似文献
7.
对中国足球体能测试的反思——写在12min跑与YOYO体能测试方法之后 总被引：5，自引：0，他引：5
对中国足球运动员体能测试的两种方法(12min跑和YOYO测试)进行了认真的分析和深刻的反思,认为这两种测试方法都存在评价标准过于统一,无视体能与技术的关系等问题,提出足协应改革足球管理体制,把体能测试的权力下放给各俱乐部,并预言体能测试最终会退出中国足球的历史舞台。 相似文献
8.
乒乓球硬度检测方法已经执行49年,其方法效率低下,不适应现代乒乓球生产线的要求.针对此缺点,提出两种检测乒乓球硬度的新方法,并用实验验证新方法的可行性,通过统计软件分析最终确定新方法具有合理性,最后探讨了对GB/T 20045-2005中关于乒乓球硬度检测方法的修改建议. 相似文献
9.
10.
目的:研究8周强制性跑台运动训练对大鼠海马NR1和NR2BmRNA表达及学习记忆能力的影响.方法:将筛选出的16只雄性SD大鼠随机分为安静对照组(C组,n=8)和运动实验组(T组,n=8),T组进行为期8周的跑台训练.第7周对两组动物分别用Y迷宫进行学习能力测试,第8周进行记忆保持(再现)测试.在最后一次运动24h后将两组大鼠断髓处死取材,使用RT-PCR法检测各组大鼠海马NR1和NR2B mRNA的表达水平.结果:经过8周跑台运动训练,T组大鼠NR1mRNA的表达量显著高于C组(P<0.01).上调55.1%;T组大鼠NR2BmRNA的表达量显著性高于C组(P<0.01),上调35.6%;Y迷宫测试结果显示,T组大鼠在学习能力和记忆保持测试中的表现均优于C组.结论:8周强制性跑台训练可以易化大鼠空间学习能力,并提高大鼠的空间记忆能力,这可能与运动训练促进了大鼠海马NR1和NR2BmRNA的表达有关. 相似文献
11.
This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue. 相似文献
12.
Roy J. Shephard 《Journal of sports sciences》2013,31(7):603-620
The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae. 相似文献
13.
许良 《体育科技文献通报》2011,19(2):1-4
基于1985、1995和2005年全国学生体质调研数据,对各时期我国城乡学生形态、机能、体能发展水平进行系统地定量研究,动态分析20年全国城乡学生体质发展的特点与规律。主要研究结果：（1）近20年城乡学生生长发育持续提前,城市学生各项形态指标生长水平高于乡村,身高城乡差距缩小,体重、胸围城乡差距加大;（2）城市学生肺活量水平高于乡村,城乡学生肺活量20年持续下降,前10年乡村学生下降快、后10年城市学生下降快;（3）乡村学生800m、1000m跑水平高于城市,城市女生50m跑、仰卧起坐水平高于乡村,其他素质城乡学生水平波动较大;（4）城市女生50m跑20年持续下降,城乡学生800m和1000m跑、城市学生50m×8往返跑20年加速下降,其他素质20年间有增有降发展极不平稳。 相似文献
14.
采用测量、问卷调查、数理统计等方法,分析定向运动学习前后对大学生身心健康的影响.结果经T检验和x2检验且表明：定向运动不仅能增强学生体质健康水平,而且有助于学生的情绪调节,增强自信心与创新意识,培养勇敢顽强的意志品质,建立良好的人际关系,能有效地促进学生身心健康发展.为了全面提高大学生整体素质,积极实践,构建定向运动课内外一体化教学模式,进行定向运动课程模块化教学,以满足学生的多元化需求. 相似文献
15.
Alan M. Nevill Roger L. Holder Andrew Bardsley Helen Calvert Stephen Jones 《Journal of sports sciences》2013,31(4):437-443
A regression analysis of competitors' tournament results in relation to their world rankings was proposed to identify the effect of home advantage in international ‘grand-slam’ tennis and ‘major’ golf tournaments. The results provided little evidence of home advantage in either the grand-slam tennis or the golf tournaments held in 1993. The only possible evidence of home advantage was found in the Wimbledon tennis and the US Open golf championships. Even these findings can be explained, at least partially, by (1) the availability of information concerning the low world rankings of the British tennis players competing at Wimbledon, and (2) selective entry, allowing only the world's top-ranked foreign golfers into the US open golf tournament. In both cases, the lower ranking home competitors have a greater opportunity to perform above their anticipated world rankings. Therefore, provided entry into tennis and golf tournaments is truly ‘open’ to both the host nation's representatives and foreign competitors alike, home advantage does not appear to be a major factor influencing the competitors' performance in such competitions. These findings may be explained by the relatively objective nature of the scoring systems used in tennis and golf, unlike the subjective influence of refereeing decisions on the results of team-games such as soccer. 相似文献
16.
17.
曲爱宁 《体育科技文献通报》2007,15(8):97-98
柔韧素质是健美操专业学生的专项素质之一,通过对普通高校健美操专业学生分组对照进行柔韧性训练的实验研究,认为对训练肌群辅以按摩器振颤刺激,可大大提高柔韧性训练效果。 相似文献
18.
我国城市体育自然环境建设与发展的研究 总被引：5，自引：0，他引：5
采用实地调查研究、理性思维研究和文献资料调研等方法对主要问题进行了专门研究，提出了进行城市体育场所区域生态功能区划、设计体育生态功能区布局的方案、做好体育场所绿色环境系统规划、制定体育场所生态与绿地管理措施等基本观点，提出了若干城市体育自然环境建设与发展的对策。 相似文献
19.
20.
重新认识体育的社会关联 总被引：3，自引：1，他引：2
体育与政治之间存在一个悖论，体育的发展与经济实力之间没有直线相关，体育与教育部分重叠，体育与宗教最为近缘，体育可借用科学手段，体育的艺术禀性日益明显，体育与养生反映着两种人生观。 相似文献