全软件数控系统整体研究与设计

全软件数控系统是一种新型的数控机床控制系统。该方法充分利用PC机的资源,采用软件进行数控插补,灵活性更强,是数控系统的发展方向。在文中,采用软件插补代替传统的硬件插补,使得系统更具开放性;采用修改系统时钟端口的时钟初值改变时钟周期,作为插补的时钟周期,满足了插补的实时性要求;采用前后台的工作模式,将实时性任务与非实时性任务分开执行,以降低实时性任务的时钟周期,提高系统实时性。     

数控铣“圆弧插补指令G02、G03”的教学过程探讨

《数控加工与编程》是高等职业教育中机电类专业的核心专业课程之一。该课程实践性较强,基本指令的教学非常重要,数控铣削加工中,圆弧插补指令G02、G03难度比较大,本文结合笔者的教学经验,总结出圆弧插补指令G02、G03编程的学习步骤,非常有利于学生的学习和灵活应用圆弧插补指令。     

论高师田径课程与教学的整体改革

运用调查、比较等方法分析研究认为田径课程与教学实际与社会、学生个体的需求产生了偏差 ,这与它的课程设置和教学内容有关。通过研究 ,提出设想与建议 ,为高师体育教学的改革寻求思索的方向和解决问题的途径 ,供教师和学生参考。     

列序聚类法和最小变化拟合在体育选材中的应用

本文应用列序聚类法和最小变化拟合于运动员选材。介绍了这种方法的基本步骤,给出了计算程序和得到解的迭代过程。结果表明,这种方法在运动员选材中是非常有效的。     

对撑竿跳高插竿起跳时心理障碍的探讨

一、前言在现代撑竿跳高运动中,随着器材的改进(尼龙竿的出现)和运动技术的不断提高,跳过的高度越来越高,人体在这种轨迹的运动中,往往会产生一种不安全感,使之在插竿起跳时出现犹豫的现象,我们称之谓心理障碍。它严重影响了插竿起跳的质量,限制了运动技术水平的提高。本文拟通过对插竿起跳时心理障碍的分析和研究,探讨克服心理障碍的方法,供参考,如有不妥,请敬同行们指正。二、研究的对象和方法     

介绍插签钓

我地多年以来就流行一种插签钓 这种插签钓类似于拉砣钓,只不过插签钓的灵敏度更高,更适合在江河的船舶上垂钓。它与竿钓比较具有钓具简单、携带方便、成本低廉、不受风雨烈日等恶劣气候影响,外出垂钓,免除爬山涉水寻找钓场之苦等特点。它集中了抛竿钓     

几种有效的标枪出枪练习

<正> 投标枪要求最后用力方向要通过标枪纵轴。为了使学生较快地掌握好这种技术,我们总结出一套专门练习,其主要特点是: 1.练习方法简单,与实际动作紧密联系,易于学生练习。 2.既可单独练习,又可与技术动作结合一起练习。 3.练习方法具有一定的趣味性。一、原地插枪练习(本文以右手投掷为例) (一)向下插枪练习练习方法:练习者两脚平行与肩同宽,投掷臂手握枪把,手臂上举,肘关节朝前,充分伸展肩关节,听口令做大臂带动小臂的鞭打式挥臂甩腕出枪动作,将枪插入小圈(见     

一种新的单循环賽的编排方法

在我国的球类、比赛中通常采用的单循环的编排方法,基本上是固定左上角,逆转一个位置产生下一轮次的比赛秩序。这种编排无论参赛队数多少,都能保证一二队在最后一轮相遇。当参赛队数为奇数时,末位补“0”,以同样方法进行编排。这种编排方法的最大缺点就是倒数第二个队总是被轮空队“跟踪追击”。这种编排方法大家都比较熟悉,故轮次表从略。     

足球教室

表示传球路线和射门路线表示跑动路线表示运球路线表示防守队员表示进攻队员表示自由人或者教练练习方法4: 要求:第一、第二传要准确,最后一传要快速及时准确,方向变化要突然。中锋队员先向相反方向扯动接应,然后要突然转身横向扯动接应,回传要准确,传后要快速向侧前方插上。最后一传队员传球落点要准确,传出球的弧度要低平、速度要快速。插上射门队员要掌握好时机,高速插向罚球区。射门时起脚要果断,动作要正确,突出快和准。3人顺时针交换练习位置。     

体育专业学生学习成绩评定的定位审思

对学生学习成绩的评定是教学工作的一个重要部分,必须合理定位.通过从认知观念、考试方法、考试内容、标准的偏差进行分析,认为对学生学习成绩的评定要转变观念,把握方向,明确评价的目的,采取多种考试形式,服务于人才培养体系.     

Carbohydrate ingestion improves endurance performance during a 1h simulated cycling time trial

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.     

Science and medicine of rowing: A review

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.     

我国体育市场管理法规研究

采用调查法和比较法对全国体育市场立法和管理现状进行调查,对部分较早出台并有一定代表性的省市的体育市场管理法规的立法和管理情况进行了研究,提出了体育市场管理立法和管理的原则、基本程序、措施及其一般模式,为规范全国体育市场管理提供参考依据。     

重新认识体育的社会关联

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。     

上海社区体育竞赛参与者的特点探析

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。     

对全面把握游泳训练环节的探讨

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。     

我国优秀游泳运动员出发技术辅助训练的研究

为改进我国优秀游泳运动员的出发技术,采用观测和实验方法,通过拍摄运动员陆上和水下出发技术录像以及出发计时,对出发技术进行运动生物力学诊断和分析。在此基础上,根据运动员自身特点和不同泳姿提出相应的入水启动方式,并研制出发训练辅助器材,对出发预备姿势、腾起角度以及飞行远度和入水角进行控制。实践证明:这是一种快捷、有效的出发技术辅助训练方法。     

运动性呼吸肌疲劳与耐力性项目的运动能力

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.     

Identifying home advantage in international tennis and golf tournaments

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.     

对欧洲足球技战术发展趋势的思考

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。