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张淑红 《中学生数理化(高中版)》2010,(12):28-28
一、教学目标1.知识与技能:掌握机械波的形成过程及其形成条件;知道机械波的种类——横波和纵波;明确机械波的传播特征.2.过程与方法:通过波的模型的建立,提高学生的空间想象能力;通过对波的模型进行分析判断,提高分析 相似文献
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机械波是机械振动在弹性介质(如水、空气等)中的传播过程。常见的机械波有声波、超声波、绳波以及液面(水)波等等。在力学的教学过程中,学生对机械波的概念,有如下几方面的问题容易混淆:(1)纵波的波形图线与横波的波形图线的区别;(2)波速、波张与频率之间的关系;(3)液面波是否是横波。本文将要讨论这三个问题。 相似文献
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蒋永玉 《中学生数理化(高中版)》2012,(1):19-20
一,机械波多解的原因
在机械波传播过程中,一个周期内的不同时刻波的形状是不同的,但在相隔时间为周期整数倍的不同时刻波的形状则是相同的,也就是说机械波在传播过程中具有周期性,机械波的这种周期性必然导致波的传播距离、时间、速度及质点振动所通过的路程等物理量具有多值性． 相似文献
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庄盛文 《数理化学习(高中版)》2006,(22)
机械波是力学部分的重要内容,综观“机械波”一章,结合考试常考察的知识点以及学生难以掌握的地方,机械波问题中有下面的七类难点:波长的判断,波的多解问题,知波的传播方向判断某质点振动方向,画Δt后的波形图,波的干涉,振动和波动的综合,多普勒效应问题·一、“波长”的确定① 相似文献
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一、教学目标知识目标：
1．理解什么是机械波，理解波的形成和传播特点。
2．知道横波和纵波，波峰和波谷，密部和疏部。
3．知道机械波，理解机械波传播振动形式，能量、信息。 相似文献
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万云方 《中学生数理化(高中版)》2008,(9)
对于机械波沿一条直线传播的情形,波传播方向的双向性和波的周期性以及质点振动方向未确定时,常会产生机械波问题的多解.因此解答上述多解问题时需要全面进行分析,以免漏解. 相似文献
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“机械波的图象”是机械波的难点,是整个力学的重点,是高考的热点．机械振动在介质中的传播,形成机械波．产生机械波的条件：同时存在振源和介质．机械波向外传播是振动形式的传播,介质中各质点不随波发生迁移．波是传递能量的一种方式．下面结合高考题,对此类题作一归纳、分析,供参考． 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
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
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
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
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
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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