滑翔机是怎样飞行的?

滑翔运动是最引人入胜的一种航空体育运动,也是青年们的一种体育运动。在一种没有发动机的叫做滑翔机的飞行器上面,人们可以在空中保持停留好几小时,航行数百公里的距离,不但能升得相当高,而且还能作一些优等航空术的特技表演。滑翔的这种锻炼能使人们熟悉飞行,培养出飞行人员的果断品质。许多苏联杰出的飞行员,例如,A.N.巴克雷斯金,A.N.莫洛得奇依等人,都是从滑翔飞行中锻     

爱熱微生物

從很早的時候,人類就在为許多不可捉摸的而每天都在周圍發生的現象尋找解釋。譬如:为什麼牛奶變質變酸?傳染病從哪裏來?为何死去的動植物有機組織腐败等等。在五、六年級學植物時,學生都知道:所有這些现象都是由各種不同的極小的單細胞生物——微生物所引起的。細菌就是微生物的一種,它是非常小的属於植物界的有生物。科學家每年都一再地揭露這些新的看不见的廣大生物界的秘密。生物學博士,斯大林獎金獲得者E. H. 米舒斯     

為改良軸承而斗爭

分不開的一對 在现代工業和日常生活所應用的许多機器之中,幾幾乎不能找出一架機器,裏面連一個迥轉部份也沒有。鬧鍾的小齒輪和蒸汽機的大飛輪,機車的輪子和機床的轉轴,縫紉機的線轴和輪船螺旋浆的主轴。車廂的轴心和狄塞耳内燃機的曲柄軸——他们在工作的時候,都是要旋轉的。而在迥轉     

GaIN (Georgia Interactive Network for Medical Information) study on health professionals' search requests and continuing education needs

Health sciences librarians are being called upon to be more proactive in their institutions' continuing education efforts. In an effort to identify whether search requests indicated CE needs, a study was conducted by a group of members of GaIN (Georgia Interactive Network for Medical Information). MEDLINE requests from health care professionals for subject specific clinical topics were collected during a six-month period via a standard search request form created for the study. Copies of all completed requests were collected and broad ICD-9 codes assigned to the search topics. Institutional reports were generated for each participating library to share with hospital CE coordinators. They were also compiled for the group as a whole, and reflected the "hottest" topics requested during the study period for physicians and for non-physicians (nurses, allied health, administrators). A survey to hospital librarians and CE educators showed some value in the reports, but greater potential for further collaboration between librarians and CE coordinators.     

哈特私通事件

1987年5月,竞选英国民主党总统候选人的加里·哈特由于新闻界披露了他的桃色新闻而退出竞选,这件事震动了美国朝野,在新闻界也引起了一场争论。争论涉及到新闻媒介的权利、责任与职业道德,新闻的真实性等方面的问题。这里编译的是美国《哥伦比亚新闻学评论》杂志最近的有关评论文章,剖析了新闻界在哈特事件中所起的作用,反映了美国新闻界一部分人的看法。     

л·康德娜季耶娃的起跑技术

在奥运会的预赛中,康德娜季耶娃战胜了哈格吕德(瑞典)、X·汉特(英国),并跑出了11″13的好成绩。康德娜季耶娃的起跑有什么样的特点呢? 在《预备》口令后,运动员采用“中间式”安装起跑器的方法,肩很容易过起跑线,身体重量均匀地分布在手臂和腿上。运动员的头放松低下,目视跑道,这表示颈部肌肉处于放松的位置。这在起跑的技术中,是一个重要的因素。因为,颈部肌肉紧张,通常将引起起跑后的第一步     

The stress of travel

International travel is an essential part of the life of elite athletes, both for competition and training. It is also becoming increasingly common among recreational sportspersons. Long-distance travel is associated with a group of transient negative effects, collectively referred to as 'travel fatigue', which result from anxiety about the journey, the change to an individual's daily routine, and dehydration due to time spent in the dry air of the aircraft cabin. Travel fatigue lasts for only a day or so, but for those who fly across several time zones, there are also the longer-lasting difficulties associated with 'jet lag'. The problems of jet lag can last for over a week if the flight crosses 10 time zones or more, and they can reduce performance and the motivation to train effectively. Knowledge of the properties of the body clock enables the cause of the difficulties to be understood (an unadjusted body clock), and forms the basis of using light in the new time zone to promote adjustment of the body clock. Sleep loss and its effects are important components of jet lag, and attempts to promote sleep by the use of melatonin and other hypnotics are also relevant. Sleep loss is also found in those who undertake challenges that involve long periods where the normal consolidated sleep of 8 h length is not possible. Advice on sleep regimens in such circumstances is given.     

提高助跑的准确性

我们的跳远和三级跳远运动员年年都提高了运动成绩,从而走在世界优秀运动员的最前列.但是,他们迄今仍然存在着助跑准确性差这一缺点.捷尔——奥尔涅祥和戈利稚夫在去年的比赛季节中,脚踏板过线的错误占全部跳跃的30-50%.费多谢耶夫和加列也尔也常犯踏板过线或过早起跳的错误.利稚霍夫斯基当助跑不准确时,就会降低成绩20——30厘米.在最优秀运动员当中,助跑较准确的一些的,只有沙波鲁谱娅和波达连柯两人.至于其余的许多运动员的助跑也往往缺乏稳定的准确性.对不准确的助跑进行分析的结果表明,在训练实践中,我们没有采用有效的方法,来帮助运动员把动     

少年篮球运动员在准备参加比赛期的训练安排

不断完善少年篮球运动员的训练体系,是广大教练员和科学工作者经常注意的研究课题。多数研究的主要问题有:教学方法;一定的训练方案对身体训练的影响;通过教育观察论证教学方法;等等。也有一些牵涉到少年篮球运动员训练安排的文章,但是为数很少。本文的任务是:研究我们制定的少年