共查询到20条相似文献，搜索用时 62 毫秒
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《实验室研究与探索》2016,(9):24-27
建立了数字微镜(DMD)数字化制作系统,通过光栅数字掩模生成、曝光、显影、PDMS复制、PDMS固化,制作了PDMS柔性薄膜光栅。将该柔性薄膜光栅应用于光栅光谱仪原理系统中,先对系统进行定标,再测量待测光源波长,波长测量相对偏差为2.10%。为了评估光栅的制作质量,采用光栅光谱仪原理系统对光栅周期进行测量,相对偏差为2.15%;利用光学轮廓仪对光栅二维、三维形貌进行检测,光栅周期相对偏差为1.45%,光栅的整体轮廓光滑,均匀性较好。制作实验及测量结果表明,基于DMD的数字化制作技术为柔性微结构及器件的制作提供了一条简单、高效、低成本、高精度制作的新途径。 相似文献
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张恒 《辽宁教育学院学报》2000,17(5):22-24,31
本文导出了同心环形光栅莫尔条纹在测量折射率方面的定量表达式，并给出了测量结果，提供了同心环形光栅莫尔条纹测量折射率的即简洁又精确的方法。 相似文献
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张援 《四川职业技术学院学报》2004,14(1):110-111
环形光栅(CG)的中间和边缘的稀密程度一样，对于相同面积的菲涅耳波带板(FZP)和CG，当CG的条纹间隔等于FZP最边缘的条纹间隔时，CG的自相关特性比FZP的自相关特性更接近于δ函数。本文在圆孔衍射的基础上，讨论环形光栅的菲涅耳衍射，并给出了计算机仿真结果。 相似文献
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研究了带均匀布拉格光栅的光纤环镜的滤波特性,并提出了一种用两个带有光栅的光纤环形镜相串联来改善环形镜滤波特性的方案.利用传输矩阵法,推导了这两种滤波器传输谱的解析表达式,分析了其滤波特性.模拟结果显示,带均匀布拉格光栅的光纤环镜的透射谱是余弦函数调制后的光纤光栅反射光谱,具有梳状滤波的特性.两个单环形镜相串联,其波形并非他们的简单叠加,而是以等比数列叠加的,级联后的效果更加类似于法布里–珀罗腔滤波器的滤波效果,可以在光纤传感和通信领域中获得更加广泛的应用. 相似文献
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从光纤光栅温度传感模型出发，分析研究光纤光栅的温度传感特性，比较裸光纤光栅与增敏光纤光栅的温度敏感性，在此基础上提出一种基于滤波法的光纤光栅解调系统，研究表明，此系统具有结构简单，操作方便，灵敏度高的优点。 相似文献
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数学课本上写到,环形的面积等于外圆的面积减去内圆的面积。指导学生学习这一内容时,我产生了一种想法:假设能把环形伸展成一个长方形(或把环形分割成相等的若干份,然后拼成一个近似长方形),按求长方形的面积公式来求环形的面积是否可以呢?带着这个想法,我试推测到:外圆的周长加上内圆的周长,然后再除以2,就相当于长方形的“长”,外圆半径减去内圆半径,就相当于长方形的“宽”。根据:“长方形的面积=长×宽”得到:“环形的面积=(外圆 相似文献
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本文对环形轨道运行物体的速度、周期等物理量随半径的变化规律进行了推导,给出了规律性的结论,并加以例题说明。 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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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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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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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