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1.
对狭义相对论中的时空性质和洛伦兹变换的教学内容作了不同于已有教科书的处理,从狭义相对论的两个基本原理出发导出“动钟延缓”、“动尺缩短”及“同时相对性”等三个时空性质,并在此基础上得到洛伦兹变换与间隔不变性,从而更好地体现狭义相对论中的物理概念和思维方法,此外还对理论物理教学改革中的有关问题作了探讨.  相似文献   

2.
主要讨论了狭义相对论中时空间隔不变在直角坐标系中的三种表达式,分析了应用间隔不变处理经典时空性质和相对论力学问题容易产生的误区,提出了正确的解决办法。  相似文献   

3.
两个事件之间隔不变性(Δs )2=(Δs)2是狭义相对论的两个基本原理与时空的均匀性及空间各向同性之直接推论;间隔不变性(ds )2=(ds)2=-dx μdx μ=-dxμdxμ给出闵可夫斯基四维空间的度规,决定了狭义相对论的时空性质;由于洛仑兹变换可由间隔不变性直接推出,所以,洛仑兹变换及伽利略变换都是对两个事件之空间、时间坐标差Δxμ与Δx μ而言的;有时,利用间隔不变性讨论问题比利用洛仑兹变换更简便.  相似文献   

4.
<正>旋转和位似是中学几何教材中重要的图形变换之一,具有丰富的几何性质和广泛的应用.如果对于一种图形同时完成旋转和位似这两种变换,又有怎样的图形性质呢?下面给予有关探究与应用.1 旋转位似定义、性质(1)定义:把一个图形绕同一点旋转一定角度,并通过位似变换得到另一个图形称为旋转位似.(2)性质:①具有位似的一切性质,对应角相等,对应线段的比等于位似比.②旋转位似图形对应边平行或共线.③任意一对对应点到位似中心的距离  相似文献   

5.
爱因斯坦引力几何化的思想是解决引力本质问题的关键,从而广叉相对论中的时空度量问题就是实现这一思想的核心问题;关于广义相对论中是否存在有如狭义相对论那样的"光速不变"问题,往往有着不同的说法,在此给出了说明.  相似文献   

6.
从狭义相对论来看,运动电荷的电磁场效应应该是静止电荷的静电效应经历时空坐标变换得到的结果,所以描述电磁效应的方程组可以从静电现象通过相对论时空变换关系——洛仑兹变换得到,本文对此进行了证明。  相似文献   

7.
证明由不同系统的局域Lorentz变换不能得到光速可变.基于狭义相对性原理必然得到一个不变速度ch.因此,狭义相对论基本原理应该严格地重新定义为:Ⅰ.狭义相对性原理,其必然导出一个不变速度ch.Ⅱ.假设理论中的这个不变速度ch是真空中的光速c.如果第二个原理不成立,例如存在超光速运动,则理论仍是形式相同,仅仅c→ch的泛狭义相对论.这是目前许多问题的一个最简单的修改.如果ch是各种不同的不变速度,则多时空体系相应于多世界.结合超光速等,发展理论的其他方法也被探索.光速可变理论应该联系于广义相对论.  相似文献   

8.
1978年,B.M.Milisavljevic建立关于三角形边长a、b、c与外接圆半径R、内切圆半径r的一个几何不等式[1]Rr≥31∑ba+c.(1)Milisavljevic不等式形式优美,且加强了著名的Euler不等式[2]R≥2r,引起了不少人的兴趣.1996年,宋庆先生撰文[2]指出,Milisavljevic不等式强于不等式Rr≥43∑b+ac;(2)该文中,作者建立了一个较(2)式强但与Milisavljevic不等式不分强弱的不等式Rr≥98???∑b+a c???2.(3)本文统一加强上述不等式,并给出一个逆向不等式.定理设a、b、c为△ABC的三边长,s、R、r分别为三角形的半周长、外接圆半径、内切圆半径,则29???∑s?a…  相似文献   

9.
以光锥和二惯性系映射的几何方法结合洛伦兹变换 ,讨论了参考系变换下不同的时空区域中事件的时间顺序 ,直观的描述了狭义相对论的因果律  相似文献   

10.
正一、教学片段片段一:整理沟通1.揭示课题:这节课我们共同整理和复习"长方形和正方形"这个单元.2.复习长方形的特征与周长计算.(1)出示一张长方形白纸(贴在黑板上),问:这张白纸是什么形状的?长方形有什么特征?这个长方形的周长在哪里,谁愿意来指一指.平面图形的周长指什么?(2)请同学们算出这个长方形的周长,现在好算吗?为什  相似文献   

11.
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.  相似文献   

12.
汉字倒说     
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。  相似文献   

13.
风的曲线     
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.  相似文献   

14.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.  相似文献   

15.
《海外英语》2007,(5):44-45
It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,  相似文献   

16.
一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/  相似文献   

17.
《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?  相似文献   

18.
钱生钱!     
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了  相似文献   

19.
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.  相似文献   

20.
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.  相似文献   

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