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71.
精确高效的相位解码在非接触光学测量中有着重要的作用, 在总结传统算法的基础上,提出一种新的相移光解码算法.该算法是以四步相移为基础,对初始的包裹相位图使用残差检测理论,检测、提取、标志出残差点,然后使用一种新的相位质量图指导剩余残差点的检测,为了使质量图中残差点的检测达到最优,对质量图进行低通滤波、锐化残差编码点,尽量使残差点能完全检测出来,并进行残差平衡处理,最终选取一个种子点使用洪水算法实现整张编码图的解码.实验结果显示该相移光解码算法能自动避开不连续区域,得到较高质量的编码结果. 相似文献
72.
Micro stereo lithography is a kind of technology utilizing the solidified effect that photo curable polymer will appear under ultraviolet (UV) laser exposure. It is widely used in three-dimensional (3D) micro fabrication. We get the experimental values of a pair of UV laser curing coefficients, absorption coefficient and critical curing energy, of curable resin by fitting the calculation results of the Gaussian beam theory and experimental curing results. The theoretical relation between the curing unit's shape and the exposure features of time and intensity of convergent Gaussian beam is presented. The calculation and experimental results of curing unit under different conditions agree well with each other. This research offers a steady base for further research about the improvement of resolution. 相似文献
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Numerical investigation of slow solitons in Bragg gratings with a hyperbolic tangent apodization 下载免费PDF全文
This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating.We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle section in order to obtain slower solitons.Optical fibre soliton but not Bragg grating soliton is used as input pulse in the discussion,which is much more approximate to the light source for the practical purpose.We discuss in detail the effects of the soliton’s velocity with some parameters in the process of transmission.The results show that by choosing special parameters,one can make the soliton slow-down with a little distortion and energy decay and obtain tunable time-delay on a small scale. 相似文献
77.
根据多镜面地基望远镜在近红外实现共相衍射极限成像的需求,提出了一种基于压电堆栈致动器的高分辨率倾斜镜设计方案。该方案以哑铃型柔性铰链和菱形位移缩小结构(RADS)作为倾斜镜的运动传递元件,压电堆栈致动器(PSA)作为动力元件,并使用电涡流传感器作为角度测量部件。介绍了高分辨倾斜镜的工作原理,并对哑铃型柔性铰链和菱形位移缩小结构进行设计。柔性铰链和位移缩小结构的关键结构参数均采用理论计算、实验和仿真进行优化。建立倾斜镜模型,利用理论计算和有限元仿真软件分别计算倾斜镜的倾斜角度和分辨率。实验结果表明:设计的倾斜镜角度分辨率达到0.017″,最大倾斜角度为14.6″,谐振频率为136.97 Hz,与有限元仿真结果相吻合,满足地基望远镜系统衍射极限成像的要求。 相似文献
78.
Charge compensation and capacity fading in LiCoO_2 at high voltage investigated by soft x-ray absorption spectroscopy 下载免费PDF全文
In order to obtain an in-depth insight into the mechanism of charge compensation and capacity fading in LiCoO_2, the evolution of electronic structure of LiCoO_2 at different cutoff voltages and after different cycles are studied by soft x-ray absorption spectroscopy in total electron(TEY) and fluorescence(TFY) detection modes, which provide surface and bulk information, respectively. The spectra of Co L2,3-edge indicate that Co contributes to charge compensation below 4.4 V.Combining with the spectra of O K-edge, it manifests that only O contributes to electron compensation above 4.4 V with the formation of local O 2 p holes both on the surface and in the bulk, where the surficial O evolves more remarkably. The evolution of the O 2 p holes gives an explanation to the origin of O_2~-or even O_2. A comparison between the TEY and TFY of O K-edge spectra of LiCoO_2 cycled in a range from 3 V to 4.6 V indicates both the structural change in the bulk and aggregation of lithium salts on the electrode surface are responsible for the capacity fading. However, the latter is found to play a more important role after many cycles. 相似文献
79.
在高壁面Zeta势下,研究滑移边界条件下满足牛顿流体模型的一类生物流体的电渗流动及传热特性,流体在外加电场、磁场和焦耳加热共同作用下流动.首先,在不使用Debye-Hückel线性近似条件时,利用切比雪夫谱方法给出非线性Poisson-Boltzmann方程和流函数满足的四阶微分方程及热能方程的数值解,将所得结果与利用Debye-Hückel线性近似所得结果进行比较,证明本文数值方法的有效性.其次,讨论电磁环境下壁面Zeta势、哈特曼数H、电渗参数m、滑移参数β对流动特性、泵送特性和捕获现象的影响,并探究焦耳加热参数γ和布林克曼数Br等参数对传热特性的影响.结果表明,壁面Zeta势、电渗参数m、滑移参数β的增大对流体速度有促进作用,而哈特曼数H的增大会抵抗流体流动.研究进一步表明,焦耳加热参数γ和布林克曼数Br的增大会导致温度升高. 相似文献
80.
Highly sensitive digital optical sensor with large measurement range based on the dual-microring resonator with waveguide-coupled feedback 下载免费PDF全文
We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case. 相似文献