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针对某坝高超过200m的碾压混凝土重力,按照DL5108-1999《混凝土重力坝设计规范》规定,以分项系数极限状态设计表达式进行结构计算,坝体应力计算采用材料力学方法,坝基抗滑稳定计算采用抗剪断公式,计算时坝段均取单宽进行。计算结果表明,各典型坝段坝基稳定满足要求;正常蓄水位、校核洪水位和施工完建工况,各典型坝段坝趾、坝踵均为压应力,坝基应力满足基岩承载力要求,施工期坝趾未出现拉应力。 相似文献
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5.“浮钓钓靠坝,深浅钓交汇”
这条钓谚虽然缺乏朗朗上口的韵味,但是它却“一针见血”地指出了钓法与钓点之间的有机联系,道出了水位深浅处钓点的最佳选择,这是对休闲野钓经验的高度概括与总结,在实战中是具有较强指导意义的。 相似文献
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5."浮钓钓靠坝,深浅钓交汇"
这条钓谚虽然缺乏朗朗上口的韵味,但是它却"一针见血"地指出了钓法与钓点之间的有机联系,道出了水位深浅处钓点的最佳选择,这是对休闲野钓经验的高度概括与总结,在实战中是具有较强指导意义的. 相似文献
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《棋艺(象棋版)》2008,(10)
我国虽然在大坝建设上取得巨大成就,但也有很多经验教训,还有很多具有挑战性的问题值得研究。中国大坝委员会秘书长贾金生先生认为,比较重要的技术问题有十个。一是新坝型。面板堆石坝、碾压混凝土坝在缩短工期、减少投资等方面起到重要的作用,代表了我国近20年来大坝发展的大趋势。基于未来发展的需要,探讨并创新研究新的坝型具有重要意义。二是环境友好的大坝建设技术标准。目前,社会对大坝的建设越来越重视。环境友好的大坝设计、施工、运行调度等技术标准研究是未来我们面临的重要任务之一。三是特高面板堆石坝。水布垭在200m级面板堆石坝应用方面做了大量的研究工作,取得丰富经验。我国未来水电发展需要建设更高的面板坝,如何创新设计、节省投资并保障安全是挑战性的课题。四是特高碾压混凝土坝。龙滩在建设200m级高碾压混凝土坝方面作出了贡献。如何确定200m级、300m级碾压混凝土坝设计准则、保障安全目前仍是值得关注的难题。五是特高拱坝。高拱坝由于坝踵部位存在难以确定的复杂应力区,在高水位运行时是否会存在安全问题,仍是世界性的技术难题。研究保障措施和更为科学的判断方法是未来一个时期的科学攻关方向之一。六是老坝的经济使用寿命、大坝退役问题。确定大坝... 相似文献
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坝后式电站由常规的电磁型保护控制系统改造为计算机监控系统。改造后应用实践表明:该系统硬、软件配置稳定性好、可靠性高、实时性强,能更好地满足电站的各种监控需求。 相似文献
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坝轴线和坝型的选择是新建水库工程设计中首要且重要的工作。在满足相关规划及规程规范要求的情况下,应充分考虑工程地质条件、施工工期、移民拆迁占地、环境影响、工程投资、工程效益等各方面的因素影响,从而选择了技术上可行、经济上合理、效益上最佳的坝轴线和坝型方案。本文对某新建水库的坝轴线和坝型的方案进行了比选,最终确定了下坝线为拟选坝轴线位置、碾压式沥青混凝土心墙石渣坝为拟选坝型的方案。 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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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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影响和限制耐力性运动项目的成绩的生理因素是复杂的和多方面的,取决于训练的强度和运动成绩.大强度持续性运动可导致呼吸肌疲劳.运动性呼吸疲劳可能在决定运动耐量方面起到关键的作用:一方面通过直接影响运动肌力量的生成(外周疲劳),另一方面,通过肢体用力自感不安反馈引起工作肌运动单位输出功率下降(中枢疲劳).对呼吸肌进行训练,可能有助于提高耐力性项目的运动成绩. 相似文献
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结合欧洲足球技战术的发展特点,就鲁能泰山足球队的体能训练、技术训练、防守阵型、进攻方式、定位球、职业态度、球星培养等诸方面所存在的不足进行了分析,提出相应的改进意见。 相似文献
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朱新新 《体育科技文献通报》2010,18(3):52-53,57
本文运用文献资料法,逻辑分析法,在遵循逻辑学、哲学、心理学原理的前提下,对竞技健美操技术的概念进行了界定,对竞技健美操技术进行了分类研究,在此基础上分析了竞技健美操技术的结构,为系统、科学的组织竞技健美操的教学和训练提供理论上的参考,为促进竞技健美操理论体系的完善和协调发展做出一定的贡献。 相似文献