共查询到20条相似文献，搜索用时 62 毫秒
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力的作用效果有两个,它既可以改变物体的运动状态,还可以使物体产生形变．如果有压力（或拉力）作用在物体上,可以使任何物体发生形变,硬度不大或比较松软的物体受到压力或拉力后,形变效果非常明显,很容易观察到,但力是否可以使非常坚硬的物体也能发生形变呢？ 相似文献
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力的作用效果有两个,它既可以改变物体的运动状态,还可以使物体产生形变.如果有压力(或拉力)作用在物体上,可以使任何物体发生形变,硬度不大或比较松软的物体受到压力或拉力后,形变效果非常明显,很容易观察到,但力是否可以使非常坚硬的物体也能发生形变呢? 相似文献
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《赤峰学院学报(自然科学版)》2021,(9)
在建筑设施、电力传输、运动器材和工矿等行业,拉力是一个需要监测的物理量。由于光纤自身的抗电磁干扰,长距离传输等优势,光纤拉力传感器可以胜任多种复杂环境的传感工作。本文将液晶、光纤谐振腔和弹性套管结合,制作出基于游标效应的单臂液晶光纤法珀拉力传感器。分别研究单臂液晶光纤法珀拉力传感器在不同波长、不同厚度的套管封装情况下光谱特性和传感灵敏度。该传感器具有传感灵敏度高、成本低、重复性好等优点。 相似文献
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拉伸法测定金属的杨氏模量实验中,一般采用光杠杆测量出细丝因受拉力而产生的微小伸长量,测出的金属丝微小形变量是否精准决定了这个实验精确度。光杠杆测量出细丝因受拉力而产生的微小伸长量理应该包括了横梁弯曲的形变量。为减小横梁形变带来的影响,提高拉伸法测杨氏模量的实验精度,可从对金属丝的形变量进行修正和改变横梁结构两方面着手。 相似文献
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一、弹力的分析某物体与其他几个物体接触,若产生了弹性形变就一定受到弹力,否则,就未受到弹力.而物体的形变是难以觉察的.因此直接由形变来判断有无弹力是不太实际的.如果借助于物体的运动状态来分析弹力,就较为方便、明确.例1如图所示,升降机自由下落,绳对物体有拉力吗?解析显然,不联系物体的运动状态,不易判断物体是否受到绳的拉力.不细心的学生,往往凭感觉就武断地说物体肯定受到绳的拉力(否则,就掉下去啦).其实,联系物体的运动状态,考虑到物体具有向下的加速度a=g,由牛顿第二定律可得mg-T=ma,即T=m(g-a)=0.可见物体不受绳的拉力.二、… 相似文献
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华青 《第二课堂(小学)》2005,(Z1)
用光纤来操纵导弹,不少同学会纳闷:光纤细如蛛丝,高速飞行的导弹会不会拉断光纤呢?这的确是光纤制导中的一个关键问题。一般市场上出售的光纤,它的拉力强度远远不能满足光纤制导的要求。但是,用于光 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
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
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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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Richard Denner 《海外英语》2007,(4):14-15
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
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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
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《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
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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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陈美曦 《山东教育学院学报》2008,23(2):103-107
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
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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