欧拉1707年出生在瑞士的巴塞尔(Basel)城,13岁就进巴塞尔大学读书,得到当时最有名的数学家约翰·伯努利(Johann Bernoulli,1667-1748年)的精心指导
欧拉渊博的知识,无穷无尽的创作精力和空前丰富的著作,都是令人惊叹不已的!他从19岁开始发表论文,直到76岁,半个多世纪写下了浩如烟海的书籍和论文到今几乎每一个数学领域都可以看到欧拉的名字,从初等几何的欧拉线,多面体的欧拉定理,立体解析几何的欧拉变换公式,四次方程的欧拉解法到数论中的欧拉函数,微分方程的欧拉方程,级数论的欧拉常数,变分学的欧拉方程,复变函数的欧拉公式等等,数也数不清他对数学分析的贡献更独具匠心,《无穷小分析引论》一书便是他划时代的代表作,当时数学家们称他为"分析学的化身"
欧拉是科学史上最多产的一位杰出的数学家,据统计他那不倦的一生,共写下了886本书籍和论文,其中分析、代数、数论占40%,几何占18%,物理和力学占28%,天文学占11%,弹道学、航海学、建筑学等占3%,彼得堡科学院为了整理他的著作,足足忙碌了四十七年
欧拉著作的惊人多产并不是偶然的,他可以在任何不良的环境中工作,他常常抱着孩子在膝上完成论文,也不顾孩子在旁边喧哗他那顽强的毅力和孜孜不倦的治学精神,使他在双目失明以后,也没有停止对数学的研究,在失明后的17年间,他还口述了几本书和400篇左右的论文19世纪伟大数学家高斯(Gauss,1777-1855年)曾说:"研究欧拉的著作永远是了解数学的最好方法"
欧拉的父亲保罗·欧拉(Paul Euler)也是一个数学家,原希望小欧拉学神学,同时教他一点教学由于小欧拉的才人和异常勤奋的精神,又受到约翰·伯努利的赏识和特殊指导,当他在19岁时写了一篇关于船桅的论文,获得巴黎科学院的奖的奖金后,他的父亲就不再反对他攻读数学了
1725年约翰·伯努利的儿子丹尼尔·伯努利赴俄国,并向沙皇喀德林一世推荐了欧拉,这样,在1727年5月17日欧拉来到了彼得堡1733年,年仅26岁的欧拉担任了彼得堡科学院数学教授1735年,欧拉解决了一个天文学的难题(计算慧星轨道),这个问题经几个著名数学家几个月的努力才得到解决,而欧拉却用自己发明的方法,三天便完成了然而过度的工作使他得了眼病,并且不幸右眼失明了,这时他才28岁1741年欧拉应普鲁士彼德烈大帝的邀请,到柏林担任科学院物理数学所所长,直到1766年,后来在沙皇喀德林二世的诚恳敦聘下重回彼得堡,不料没有多久,左眼视力衰退,最后完全失明不幸的事情接踵而来,1771年彼得堡的大火灾殃及欧拉住宅,带病而失明的64岁的欧拉被围困在大火中,虽然他被别人从火海中救了出来,但他的书房和大量研究成果全部化为灰烬了
沉重的打击,仍然没有使欧拉倒下,他发誓要把损失夺回来在他完全失明之前,还能朦胧地看见东西,他抓紧这最后的时刻,在一块大黑板上疾书他发现的公式,然后口述其内容,由他的学生特别是大儿子A·欧拉(数学家和物理学家)笔录欧拉完全失明以后,仍然以惊人的毅力与黑暗搏斗,凭着记忆和心算进行研究,直到逝世,竟达17年之久
欧拉的记忆力和心算能力是罕见的,他能够复述年青时代笔记的内容,心算并不限于简单的运算,高等数学一样可以用心算去完成有一个例子足以说明他的本领,欧拉的两个学生把一个复杂的收敛级数的17项加起来,算到第50位数字,两人相差一个单位,欧拉为了确定究竟谁对,用心算进行全部运算,最后把错误找了出来欧拉在失明的17年中;还解决了使牛顿头痛的月离问题和很多复杂的分析问题
欧拉的风格是很高的,拉格朗日是稍后于欧拉的大数学家,从19岁起和欧拉通信,讨论等周问题的一般解法,这引起变分法的诞生等周问题是欧拉多年来苦心考虑的问题,拉格朗日的解法,博得欧拉的热烈赞扬,1759年10月2日欧拉在回信中盛称拉格朗日的成就,并谦虚地压下自己在这方面较不成熟的作品暂不发表,使年青的拉格朗日的工作得以发表和流传,并赢得巨大的声誉他晚年的时候,欧洲所有的数学家都把他当作老师,著名数学家拉普拉斯(Laplace)曾说过:"欧拉是我们的导师" 欧拉充沛的精力保持到最后一刻,1783年9月18日下午,欧拉为了庆祝他计算气球上升定律的成功,请朋友们吃饭,那时天王星刚发现不久,欧拉写出了计算天王星轨道的要领,还和他的孙子逗笑,喝完茶后,突然疾病发作,烟斗从手中落下,口里喃喃地说:"我死了",欧拉终于"停止了生命和计算"
欧拉的一生,是为数学发展而奋斗的一生,他那杰出的智慧,顽强的毅力,孜孜不倦的奋斗精神和高尚的科学道德,永远是值得我们学习的欧拉在数学上的建树很多,对著名的哥尼斯堡七桥问题的解答开创了图论的研究。欧拉还发现 ,不论什么形状的凸多面体,其顶点数v、棱数e、面数f之间总有v-e+f=2这个关系。v-e+f被称为欧拉示性数,成为拓扑学的基础概念。在数论中,欧拉首先引进了重要的欧拉函数φ(n),用多种方法证明了费马小定理。以欧拉的名字命名的数学公式、定理等在数学书籍中随处可见, 与此同时,他还在物理、天文、建筑以至音乐、哲学方面取得了辉煌的成就。〔欧拉还创设了许多数学符号,例如π(1736年),i(1777年),e(1748年),sin和cos(1748年),tg(1753年),△x(1755年),∑(1755年),f(x)(1734年)等
Leonhard Euler (pronounced Oiler; IPA [ˈɔʏlɐ]) (April 15, 1707 – September 18 [OS September 7] 1783) was a pioneering Swiss mathematician and physicist, who spent most of his life in Russia and Germany He published more papers than any other mathematician in history[1]
Euler made important discoveries in fields as diverse as calculus and topology He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function[2] He is also renowned for his work in mechanics, optics, and astronomy
Euler is considered to be the preeminent mathematician of the 18th century and one of the greatest of all time He is also one of the most prolific; his collected works fill 60–80 quarto volumes[3] A statement attributed to Pierre-Simon Laplace expresses Euler's influence on mathematics: "Read Euler, read Euler, he is a master for us all"[4]
Euler was featured on the sixth series of the Swiss 10-franc banknote[5] and on numerous Swiss, German, and Russian postage stamps The asteroid 2002 Euler was named in his honor He is also commemorated by the Lutheran Church on their Calendar of Saints on May 24
Contents [hide]
1 Biography
11 Childhood
12 St Petersburg
13 Berlin
14 Eyesight deterioration
15 Last stage of life
2 Contributions to mathematics
21 Mathematical notation
22 Analysis
23 Number theory
24 Graph theory
25 Applied mathematics
26 Physics and astronomy
27 Logic
3 Philosophy and religious beliefs
4 Selected bibliography
5 See also
6 Notes
7 Further reading
8 External links
[edit] Biography
[edit] Childhood
Swiss 10 Franc banknote honoring Euler, the most successful Swiss mathematician in historyEuler was born in Basel to Paul Euler, a pastor of the Reformed Church, and Marguerite Brucker, a pastor's daughter He had two younger sisters named Anna Maria and Maria Magdalena Soon after the birth of Leonhard, the Eulers moved from Basel to the town of Riehen, where Euler spent most of his childhood Paul Euler was a family friend of the Bernoullis, and Johann Bernoulli, who was then regarded as Europe's foremost mathematician, would eventually be an important influence on the young Leonhard His early formal education started in Basel, where he was sent to live with his maternal grandmother At the age of thirteen he matriculated at the University of Basel, and in 1723, received a masters of philosophy degree with a dissertation that compared the philosophies of Descartes and Newton At this time, he was receiving Saturday afternoon lessons from Johann Bernoulli, who quickly discovered his new pupil's incredible talent for mathematics[6]
Euler was at this point studying theology, Greek, and Hebrew at his father's urging, in order to become a pastor Johann Bernoulli intervened, and convinced Paul Euler that Leonhard was destined to become a great mathematician In 1726, Euler completed his PhD dissertation on the propagation of sound with the title De Sono[7] and in 1727, he entered the Paris Academy Prize Problem competition, where the problem that year was to find the best way to place the masts on a ship He won second place, losing only to Pierre Bouguer—a man now known as "the father of naval architecture" Euler, however, would eventually win the coveted annual prize twelve times in his career[8]
[edit] St Petersburg
Around this time Johann Bernoulli's two sons, Daniel and Nicolas, were working at the Imperial Russian Academy of Sciences in St Petersburg In July 1726, Nicolas died of appendicitis after spending a year in Russia, and when Daniel assumed his brother's position in the mathematics/physics division, he recommended that the post in physiology that he had vacated be filled by his friend Euler In November 1726 Euler eagerly accepted the offer, but delayed making the trip to St Petersburg In the interim he unsuccessfully applied for a physics professorship at the University of Basel[9]
1957 stamp of the former Soviet Union commemorating the 250th birthday of Euler The text says: 250 years from the birth of the great mathematician and academician, Leonhard EulerEuler arrived in the Russian capital on May 17, 1727 He was promoted from his junior post in the medical department of the academy to a position in the mathematics department He lodged with Daniel Bernoulli with whom he often worked in close collaboration Euler mastered Russian and settled into life in St Petersburg He also took on an additional job as a medic in the Russian Navy[10]
The Academy at St Petersburg, established by Peter the Great, was intended to improve education in Russia and to close the scientific gap with Western Europe As a result, it was made especially attractive to foreign scholars like Euler: the academy possessed ample financial resources and a comprehensive library drawn from the private libraries of Peter himself and of the nobility Very few students were enrolled in the academy so as to lessen the faculty's teaching burden, and the academy emphasized research and offered to its faculty both the time and the freedom to pursue scientific questions[8]
However, the Academy's benefactress, Catherine I, who had attempted to continue the progressive policies of her late husband, died the day of Euler's arrival The Russian nobility then gained power upon the ascension of the twelve-year-old Peter II The nobility were suspicious of the academy's foreign scientists, and thus cut funding and caused numerous other difficulties for Euler and his colleagues
Conditions improved slightly upon the death of Peter II, and Euler swiftly rose through the ranks in the academy and was made professor of physics in 1731 Two years later, Daniel Bernoulli, who was fed up with the censorship and hostility he faced at St Petersburg, left for Basel Euler succeeded him as the head of the mathematics department[11]
On January 7, 1734, he married Katharina Gsell, daughter of a painter from the Academy Gymnasium The young couple bought a house by the Neva River, and had thirteen children, of whom only five survived childhood[12]
[edit] Berlin
Stamp of the former German Democratic Republic honoring Euler on the 200th anniversary of his death In the middle, it is showing his polyhedral formulaConcerned about continuing turmoil in Russia, Euler debated whether to stay in St Petersburg or not Frederick the Great of Prussia offered him a post at the Berlin Academy, which he accepted He left St
在一般的健身俱乐部中,椭圆机(elliptical trainer)是相当常见的心肺适能运动训练工具,而且也广为使用者喜爱。椭圆机的运动型态类似越野滑雪(cross-country skiing)的动作,因此椭圆机的英文名称也称为elliptical cross-trainer。椭圆机被设计出来的时间虽短,但是由於受到大众的喜爱,因此发展也相当的迅速。可惜,到目前为止,在运动生理学的专业书籍中,介绍这个新运动工具的运动生理反应资讯还不多。
大部分有关椭圆机运动的生理反应研究,是在2000年以后才被发表出来。Mercer, Dufek, and Bates (2001)以5名女性、9名男性,年龄250±46岁、身高178±010公尺、体重715±133公斤的自愿参与者,进行跑步机与椭圆机运动的渐增强度运动测验,跑步机的测验流程是以每1分钟为一阶段,由速度13 m/s、坡度3%开始,第二、第三、第四阶段的坡度为8%,速度分别为16 m/s、18 m/s、22 m/s,第五阶段开始坡度维持8%,速度则每阶段增加02 m/s,一直运动到衰竭。椭圆机的测验流程也是以每1分钟为一阶段,踩踏频率(以右脚踏板为准)由60 rpm开始,每分钟增加5 rpm,四阶段以后阻力增加1个水准(椭圆机机器设定的阻力水准),一直运动到衰竭。研究结果(如下图所示)发现,椭圆机测验到的VO2max为516±107 ml/kg/min、HRmax为1912±115 bpm、RPE(Borg's自觉量表,6-20 scales)为185(没有标准差详细资料)、渐增负荷运动时的VO2与HR相关为 88(p< 05),跑步机测验到的VO2max为530±77 ml/kg/min、HRmax为1934±94 bpm、RPE为187(没有标准差的详细资料)、渐增负荷运动时的VO2与HR相关为 95(p< 05)。由此可见,椭圆机运动时的生理反应情形,与跑步机运动时极为类似。
椭圆机与跑步机最大运动的生理反应(Mercer, Dufek, & Bates, 2001)
Batte, Evans, Lance, Olson, and Pincivero(2003)以8名男性、12名女性,年龄253±34岁、身高1704±90公分、体重676±112公斤的志愿受试者,以Precor EFXTM 544 Elliptical Cross-trainer进行两次不同型态的运动(一次渐增强度的最大运动[测验流程如下表所示]、一次自觉量表为6[以Borg CR-10 scale评量,代表约以60%的强度]的强度进行15分钟的固定强度非最大运动)。
时间 踏踏频率(cadence, strides/min) 阻力(resistance)
0 120 2
1 140 2
2 160 2
3 180 2
4 180 3
5 180 4
6 180 5
7 180 6
8 200 6
9 200 7
10 220 7
渐增强度的VO2max测验结果显示,受试者的平均运动测验时间约7分30秒±1分15秒、平均VO2max为478±92 ml/kg/min、平均HRmax为188±782 bpm。以6的自觉量表强度进行椭圆机运动时的VO2与HR如右图所示,达到稳定状态时的VO2百分表为752±129%,HR则为910±61%。研究结果显示,以椭圆机进行自觉强度的运动时,VO2与HR都会有偏高的现象,特别是心跳率的偏高情形相当明显。
Dalleck, Kravttz, and Robergs (2004)则以10名男性、10名女性,年龄295±71岁、身高1733±126公分、体重723±79公斤、体脂肪173±50%,自愿参与实验的大学生与研究生,进行修正Balke跑步机VO2max测验流程,以及椭圆机的VO2max渐增负荷测验流程。修正Balke跑步机VO2max测验流程,受试者在没有坡度的情况下,在2分钟内自己选择一个适当的跑步速度;在开始测验后的3分钟后,每分钟坡度增加1%,一直跑步到衰竭(下图)。
修正Balke的跑步机VO2max测验流程(Dalleck, Kravttz, & Robergs, 2004)
椭圆机的VO2max渐增负荷测验流程方面,依据受试者的性别与每周参与活动的时间分为训练组(每周3-5小时)与休闲组(每周2-3小时),依据下图所示的方式,随著运动测验时间的增加,踩踏频率与阻力也随著提高,并且以踩踏频率低於目标频率20步(strides/min),做为判定是否达到最大努力的标准。研究的结果显示(下表),椭圆机与跑步机的测量的VO2max、HRmax、RERmax等皆没有显著差异。透过椭圆机进行渐增强度的最大努力运动测验,可以获得与跑步机类似的运动生理反应。
椭圆机的VO2max测验流程(Dalleck, Kravttz, & Robergs, 2004)
椭圆机与跑步机进行最大努力测验的生理反应比较
变项 VO2max
(ml/kg/min) HRmax
(b/min) RERmax 持续时间
(min)
椭圆机
(范围) 473±64
(354-571) 1844±88
(159-197) 125±009
(105-137) 1217±140
(960-1472)
跑步机
(范围) 479±68
(340-615) 1857±77
(163-199) 122±010
(103-134) 1156±160
(831-1325)
Wiley, Mercer, Chen, and Bates (1999)研究发现,PreCor牌的椭圆机,进行渐增强度最大运动测验获得的VO2max与HRmax,与利用跑步机进行VO2max与HRmax测验的结果并没有不同。Larsen and Heath (2002)研究发现,不同踩踏频率(每分钟56, 69, 80转)的椭圆机运动,会有VO2(207±28, 252±34, 302±43 ml/kg/min)与HR(1193±170, 1357±182, 1527±210 bpm)生理反应上的显著差异。Picard等(2002)以PreCor EFX 546型椭圆机,进行椭圆机预测能量消耗与实际消耗的比较,结果发现在较高阻力时的能量消耗预估值,会有显著高估实际能量消耗的现象。Schorner, Treeacciano, Hickner, and McCammon (2004)的研究则再次验证PreCor EFX546型椭圆机高估能量消耗。Browder and Dolny (2002)的研究则发现,椭圆机的活动方向(向前或向后)与不同的步长,会显著影响下肢肌群的活动方式。Dolny, Hughes, Caylor, and Browder (2004)的研究则发现,不仅椭圆机的阻力会显著影响到VO2、HR、RER、RPE的反应,椭圆机步长(45cm, 53cm, 59cm, 65cm)的差异,也会显著影响到VO2与HR,但是RPE与RER则不会受到步长的影响。
尽管大部分的研究发现,最大椭圆机运动的VO2max与跑步机运动没有显著的差别,但是,仍有研究发现,利用椭圆机运动进行最大运动时的VO2max与HRmax皆显著低於跑步机运动(Wallace, Sforzo, & Swensen, 2004);而且,三个自觉强度(RPE,11、13、15)下的VO2、HR与能量消耗(energy expenditure),都有跑步机运动显著高於椭圆机运动的现象,而且在性别上也没有显著的不同。在一般相同自觉运动强度的条件下,跑步机会产生较大的能量消耗,椭圆机则可能因为腿部局部的肌肉负荷较大,让使用者感觉比实际的能量消耗还艰难一些。
事实上,Egana and Donne (2004)的研究显示,椭圆机的训练效果(12周)与踏步机(Stair climbing)、跑步机类似,代表椭圆机已经被证实是有效的有氧适能训练工具。运动生理学的研究者,有必要针对椭圆机踏踏频率快慢(有些文献以两脚的步数计算、有些以单脚完成的圈数计算)、阻力大小、步长幅度(包含身高差异的影响)等变项,进行详细的研究与规范,以便让使用椭圆机的一般社会大众,确实享受到椭圆机运动的效益。
美国篮球体能训练教练协会(National Basketball Conditioning Coaches Association)所出版,并由马刺队总教练Gregg Popovich写序的《Complete Conditioning for Basketball》篮球体能与肌力训练的书籍。
(一)体能训练就是能量系统的训练,而篮球比赛所使用的能量系统,约有85%来自於无氧,15%来自於有氧。因此,对於篮球的体能训练应著重在无氧系统上 – 反覆短时间、高强度的输出并进行快速的恢复。而关於能量系统,整理一下,不懂的部份,在体能训练的书籍都会有详细说明:
1 ATP-CP 系统:高强度活动的燃料来源,但只能供应约10秒。
2 醣酵解系统:一旦ATP-CP 系统接近耗竭,有更多的燃料会来至此系统,持续10秒~2分钟。
3 有氧系统:若活动持续时间更长,此系统会成为的主要的燃料供应商。
篮球比赛中是由一连串「反覆、快速、高强度的动作」搭配「动作间的短休息」所组成。体能好的篮球员,可以更长时间维持高水准的表现,并在短暂的休息时间内进行更快的恢复。所以,在安排体能的训练时,你要选择合适的「Work-Rest」比例,来发展并改善你的能量(恢复)系统。
■ 短期恢复
1 ATP-CP 能量系统,在30秒的休息中,可以恢复到50%。这30秒的时间,差不多是罚球或是20秒短暂停的时间。但若要进行完全的恢复,需要2~5分钟的时间,差不多是长暂停、每节结束的时间。
2 醣酵解能量系统,在20~30分钟的时间可以恢复50%,若要完全恢复的话,需要1个小时或以上。
■ 长期恢复
体能长时间的恢复,从2天至数天不等,取决於比赛时营养消耗、酵素消耗及组织的损坏。良好的复合式碳水化合物饮食(篮球活动主要的能量来源)、适当的休息及有品质的训练菜单将有助於身体恢复、修复及补给。
体能的训练分成四个时期,off-season、preseason、in-season及postseason。 在开始进行练习及比赛前,要在体能上获得到最大的进步,off-season是最佳时机。而preseason及in-season阶段的重点则在於练习及比赛。而postseason则是恢复的时间。
(二)赛季后恢复的时间
《Off-Season Conditioning (Off-Season的体能训练)》
书上提供了12周的体能训练,为著长时间、高强度赛季的比赛做准备。找出你开始训练的第一次,开始你12周的体能训练。这计划的开始,会先从在田径场上400公尺中强度的跑步,循序渐进的转换成球场上专项的体能训练。
在Off-Season,一星期安排:2次的体能训练、2次的增强式训练、1次的敏捷性训练。而体能的计划如下:
1 2周的400公尺Strides
2 2周的200公尺Strides
3 2周的Sprints
4 2周的转换期 (1天是Sprints、1天是球场上的体能训练)
5 4周的球场上的体能训练
注:Striders:指的就是中强度的跑步,比起慢跑来的快,跑起冲刺的慢,大概是3/4的速度。
注:Sprints:全力冲刺。
在主动恢复的期间,运动应该从事其它的运动来维持健康、保持身材,或是开始进行肌力训练的初期,或是从事非正式、随兴的篮球比赛。若球员没有任何的活动的话,则需要进行一些体能的活动,像是健行、骑自行车、慢跑或游泳。在跑步机、踏步机、椭圆机或健身脚踏车上,每周进行2或3次,每次进行20~40分钟,这样的体能训练也可以。
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