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本文主要通过介绍模态分析的产生与发展以及实验模态的测试方法,进一步了解机械动力学研究与分析的基本内容和所要求解的结果.结合机床的优化设计过程,阐述了实验模态及模态分析在机床设计中的应用. 相似文献
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论述了模态分析在叶片结构设计中的重要性,建立了叶片的三维模型,采用ANSYS软件进行了模态分析,并对计算结果进行了分析,对叶片结构设计及优化有一定的意义。 相似文献
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传递损失作为消声器的固有特性,通常用作消声器设计和仿真分析的评价标准,提出一种适用于进出口非规则截面改进的管道模态方法代替效率较低的传统方法来估算传递损失,并扩展了现有管道模态方法仅适用于进出口截面规则的限制,对规则截面进行计算和验证,三种方法吻合较好,而对于非规则截面,通过与传统方法比较,结果吻合较好,而现有管道模态方法则失效,因此可以采用改进的管道模态 方法快速估算传递损失. 相似文献
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本文介绍一种典型的ICA算法---Fast-ICA算法的基本原理及其在瞬时混合语音信号盲分离中的应用与实现,通过对三路随机混合语音信号进行的分离实验,说明了Fast-ICA算法可以用于分离超高斯语音信号,且具有较快的收敛速度,证明了其在瞬时混合盲语音信号分离中的现实有效性。 相似文献
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使用PVDF传感器采集人体生理信号,提出了基于CSI的生理信号处理算法,通过算法处理得到心率、呼吸率、体动以及呼吸暂停等参数。本文还设计了云服务器端对人体生理参数进行接收、存储和处理,根据采集到的生理参数本文选用了PNQ量表对睡眠质量进行分析,同时本文还设计了手机端软件将睡眠者的睡眠质量显示给用户。系统测试结果显示算法处理得到的心率/呼吸率与受试者实际的心率/呼吸率基本吻合,并且与穿戴式设备相比,该系统表现出较高性能。 相似文献
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在借鉴了计算机视觉技术和多媒体处理算法的基础上,提出了一种基于全自动高效视频分析框架的分析和总结的体育视频分析结构。本视频分析框架拟从底层特征提取、中级关键基元生成出发,初步实现体育视频中的镜头分类和运动对象识别以及跟踪等。分析框架中包含了一些中低级别的足球视频镜头分类处理算法,如主色区域检测,鲁棒镜头边界检测,以及目标检测等等。 相似文献
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李世明 《天津体育学院学报》2004,19(2):45-47
在前人工作的基础上,提出了一种以实测为基础,对人体环节参数进行最优化计算的方法与程序,以更加突现人体环节参数的个体化特征。最优化算法的原则是:目标函数以郑秀瑗数据模型计算值为基础达到最优化,约束条件以实际测量为准则规定决策变量的可行解。 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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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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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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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
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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
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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