排序方式: 共有20条查询结果,搜索用时 15 毫秒
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昆虫翅膀的运动参数测量研究 总被引:1,自引:0,他引:1
研究可用于精确测量昆虫运动参数的条纹投影法.应用具有高衍射效率的声光调制器(AOD)生成投影条纹,通过调整各衍射光束的角度获得不同角间距的条纹,可用来测量反射比较低的昆虫翅膀.结合AOD和光栅,从两个相互垂直的方向投射条纹,可以在>90°的测量范围内测量蜜蜂的拍打翅膀.结果表明,在蜜蜂的一个拍打周期内,用该方法可以有效地测量其拍打角、滞后角,扭转角和扭转变形,相对测量误差<2%. 相似文献
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介绍了一种二维跟踪自由游动的鱼的视频系统. 该系统由一个计算机控制的二维平台以及安置在平台上两个 CCD 相机组成. 这两个相机能同时跟踪拍摄鱼的底视和侧视图. 通过处理跟踪时记录的图像可获得鲫鱼在前游、倒游和拐弯3种运动模式下的身体曲线以及尾鳍和胸鳍的运动学参数. 相似文献
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In-situ end-point detection during ion-beam etching of multilayer dielectric gratings 总被引:1,自引:0,他引:1
An in-situ end-point detection technique for ion-beam etching is presented. A laser beam of the same wavelength and polarization as those in the intended application of the grating is fed into the vacuum chamber, and the beam retro-diffracted by the grating under etching is extracted and detected outside the chamber. This arrangement greatly simplifies the end-point detection. Modeling the grating diffraction with a rigorous diffraction grating computer program, we can satisfactorily simulate the evolution of the diffraction intensity during the etching process and consequently, we can accurately predict the end-point. Employing the proposed technique, we have reproducibly fabricated multilayer dielectric gratings with diffraction efficiencies of more than 92%. 相似文献
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分析了基于锥面衍射的双光栅光谱合成系统的可行性,设计了激光入射角为Littrow角附近的双多层介质膜(MLD)光栅光谱合成系统,开展了两路合成实验。当入射极角等于自准直入射角,入射方位角为6°时,光栅衍射效率近似等于光束自准直入射时的衍射效率。基于锥面衍射原理,对中心波长为1050.24 nm和1064.33 nm的两束光纤激光子束进行合成,入射极角为43.99°,测得合成效率为92.9%,较基于非锥面衍射的双光栅光谱合成系统的合成效率提高了8.8%;测得合成光斑光束质量Mx2=1.204,My2=1.467,与基于非锥面衍射的双光栅光谱合成系统输出光斑光束质量基本一致。 相似文献
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利用导波耦合角度实时控制光刻胶光栅掩模的占宽比 总被引:1,自引:1,他引:0
研究一种控制多层介质膜上的光刻胶光栅掩模占宽比(线宽与周期之比)的新方法。该方法基于下面的原理:如果某泄漏模在包层中的隐失尾较强,那么它的等效折射率受光刻胶光栅占宽比变化的影响就大,从而可以利用耦合角度来实时控制光栅占宽比。在光栅制作的显影阶段,采用实时监测技术,根据耦合角度和占宽比之间的关系预设入射光角度,在出现共振反常的时刻停止显影来控制占宽比。实验结果表明,固定适当的入射角度可以得到特定的占宽比;改变入射角度,占宽比按照预计的规律变化,因此定性地验证了这种占宽比控制方法的可行性。文中给出了监控装置和具体的实验方法,并讨论了误差来源和影响。 相似文献
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This study shows that the principle of a recently proposed common-path laser interferometer containing a planar grating is nonexistent and apparently caused by a mathematical derivation error. Both p-and s-polarized beams in the proposed setup experience once the +1st-order diffraction and once the-1st-order diffraction by the grating. As a result, the phase of each beam remains unchanged and the interference fringes formed by the two beams are not expected to move when the grating is translated in the grating vector direction. We perform an experiment to confirm this prediction. Both our analysis and experimental observation cast doubt on the experimental results of the authors who proposed the interferometer. 相似文献