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我们主要在数学领域讨论等价关系的定义与性质,它在数学领域和计算机领域都有着广泛的实际应用.本文先从等价关系的定义和性质入手,将等价关系应用于求极限和判定无穷积分、无穷级数的敛散性. 相似文献
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无穷限积分和瑕积分的对数判别法是一种新的敛散性判别法,但在理论上还不完整.本文给出几个有意义的实例,对于退化情况进行补充说明. 相似文献
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我在整理邮品时发现一种"济南／历城敛简"日戳,颇感有趣。本人认为"敛筒"应为"筒敛",与"筒取"的意思相同,从筒中收起、取出。"敛筒"岂不成了"取筒",不是取信了。 山东历城刻用"电子汇兑中心"日戳,直径30mm,以适应电子汇兑业务。 相似文献
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在对饵料溶散性的认识上，经常野钓的钓友由于顾忌小鱼闹钩等原因，普遍认为溶散性强的饵料在钩上的附钩时间短，不抗小鱼骚扰，当大鱼进窝后钩上可能已经被小鱼啃得没有饵了，不利于钓大鱼。即使水中小鱼不多，很多钓友由于抛竿技术不正确，造成溶散性强附钩性差的饵抛不进钓点，习惯上也经常将饵料做得又硬又粘，使饵料的溶散性变得很差，他们认为只有这样才更容易钓到大鱼。但我个人认为，在钓大鱼时饵料适当的溶散性应该是利大于弊。众所周知，野生环境的大鱼主要是以水下的动植物碎屑为食，而又硬又粘的大块状饵料在野生环境中是不容易碰到的， 相似文献
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吴周文 《徐州教育学院学报》2002,17(3):68-70
散经过一级分类与二级分类的历史过程而成为现在的艺术性散。散体基本审美特征主要表现为体裁交叉的边缘性、本显在的“自我”性、题材质的非虚构性与“最不讲技巧”的艺术性等，认识这些基本特征，才能实现对散的审美把握。 相似文献
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散杂居地区农民体育健身工程,就全国而言相对薄弱。文章主要通过田野工作、质性研究与问卷调查等方法,对南方部分民族散杂居地区农村农民体育开展基本状况进行了实地调研,结果显示：我国南方民族散杂居地区农民体育呈现不均等化、不定期化、不制度化和不科学化的状态。笔者相应地从制度、机制、观念、措施等方面对发展散杂居地区农民体育提出了对策。 相似文献
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本文介绍了高等数学中极限计算的常用方法,并通过典型实例进行分析归纳,针对其中需要注意的细节和技巧加以说明,希望对高职院校的学生在高等数学的学习过程中有一定的指导意义. 相似文献
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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
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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
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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
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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
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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
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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
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本文在专家访谈、问卷调查、数理统计和文献资料分析的基础上,探析了上海社区体育竞赛参与者的特点、参与者对社区体育赛事运作管理的看法等问题。在此基础上从引进社区体育赛事的志愿者、整合社区体育赛事的各种资源、开发社区体育竞赛的无形资产、组建非营利性的专业团队、规范社区体育赛事的服务管理等方面提出了进一步满足上海社区居民日益增长的体育竞赛参赛需求的对策与措施。 相似文献
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对全面把握游泳训练环节的探讨 总被引：4，自引：0，他引：4
从系统观点出发,结合训练实践,对全面把握游泳训练环节进行探讨。认为应强化非智力因素在运动员多年训练中的作用,在育材全过程中不断选材,从整体上把握动态训练的全过程,把培养高水平运动员的整个过程置于一个严格的科学控制之下。 相似文献
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提高重大体育赛事风险识别能力的研究 总被引：1，自引：0，他引：1
范明志 《体育科技文献通报》2011,19(1):120-122
以风险管理理论为基础,采用文献资料法和访谈法,对重大体育赛事风险识别的理论进行了研究.建构了重大体育赛事风险识别的过程模式;提出了重大体育赛事风险识别的技术方法. 相似文献