共查询到20条相似文献,搜索用时 434 毫秒
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提出了一种利用粒子近前向散射光的PIV技术,可对两维流场的瞬态流速分布进行测量,且散射光强可大为提高和测量结果不受成像系统景深的限制。对两种PIV技术进行了实验比较。 相似文献
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利用黎卡地贝塞尔函数模拟了不同粒子尺度的散射光强和偏振特性.当粒子尺度增加时,散射光强增加;水平偏振变得不对称,而垂直偏振没有变化;当粒子的折射率虚部增加时,散射光强减少.从粒子的这些散射特性和偏振特性,可以测量和分辨不同尺度的粒子. 相似文献
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由于现有单激光告警系统只能实现来袭激光一维的方位和波长等信息,提出了一种单激光告警系统同时测得二维方位信息和波长信息的新方法,该方法的光学系统主要由遮光罩、光栅、透镜组和面阵CCD组成,通过对来袭激光经过光栅后的一级和零级衍射光斑位置的判决,得到来袭激光二维方位和波长信息。通过理论分析说明了该方法的原理,并推导得出二维方位角和波长的测量公式,根据要求推导确定了光学元件参数,并通过实验验证了其可行性。实验结果显示波长分辨率小于10 nm,角度分辨率小于1x方向视场角为30,y方向视场角为15。 相似文献
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均光波导多层存储器的原理和实验 总被引:2,自引:1,他引:2
介绍了均光波导多层存储器的基本结构和原理。波导多层存储器通过收集波导侧面信息符发出的散射光来读取数据,而均光波导多层存储器的设计主要是为了解决波导多层存储器侧面散射光强不均匀的问题。有一种方法就是通过改变信息符深度来实现均光。理论推导表明信息层表面的信息符深度沿着传导光传播方向逐渐增加时可以实现波导侧面散射光强的均匀分布,而且波导各个不同位置处信息符的深度值也可以通过拟合和计算得到。为了证明理论的正确性,设计了原理性实验,完成了原理性实验器件的研制。实验对均光波导多层存储器的结构、原理以及均光方法的可行性进行了验证。实验还将均光波导多层存储器的性能与一般的波导多层存储器作了对比,实验效果良好。 相似文献
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Deflection curvature measurement can offer a number of advantages compared with the well-established strain measurement alternative. It is able to measure thin structure; fiber has no resistance with force, which leads to a high precision. There are many kinds of curvature gauges with different operation principles. A low-cost curvature optical fiber sensor using bend enhanced method to improve its curvature measurement sensitivity was devel-oped in recent years. This sensor can distinguish between convex bending and concave bending and has a good linearity in measuring large curvature deformation. Whisper gallery ray theory and Monte Carlo simulation are new achievements by computer experiment. The operation mechanism of this curvature optical fiber sensor is presented based on light scattering theory. The attenuation is ascribed to the transmission mode changing by the curvature of the fiber, which affects the attenuation of the surface scattering. The mathematical model of relationship among light loss, bending curvature, surface roughness, and parameters of the fiber's configuration is also presented. We design different kinds of shapes of sensitive zones; each zone has different parameters. Through detecting their output optical attenuations in different curvatures and fitting the results by exponential decaying functions, the proposed model is demonstrated by experimental results. Also, we compare the experi-mental results with the theoretical analysis and discuss the sensitivity dependence on bending direction. 相似文献
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Wei-Chih Wang Afromowitz M. Hannaford B. 《IEEE transactions on bio-medical engineering》1994,41(3):298-304
The authors propose an optical method using forward light scattering to measure the deflection of a micropipette from a normal contact force with a small elastic solid, and the damping coefficient of a small fluid sample through a dynamic interaction with the pipette. An analytical and experimental study of this sensor is performed and described for each property. Topics covered include: (1) forward light scattering technique for determining the diameter of a micropipette (using exact and simplified geometric interference theories); (2) deflection measurement and analysis on the pipette-sample system using the finite element method; and (3) equivalent damping coefficient and resonant frequency measurement of the pipette-fluid system and its numerical solution derived from the finite element model. A comparison of the experimental results and the analytical results is included to provide the means for analyzing the potential of this new method 相似文献
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伪装材料表面偏振散射的几何光学解 总被引:2,自引:1,他引:1
散射光的偏振特征可以作为遥感信息来识别目标,给伪装技术带来了新的威胁.文中采用偏振相机在光学与红外波段测试了染料型和涂料型伪装材料的偏振散射光谱,研究了不同探测波段下粗糙材料表面的偏振散射机理.研究结果表明:染料型伪装材料的偏振度很小,当光源以不同的入射角照射其表面时,偏振度基本保持不变;涂料型伪装材料的偏振度较大,且随着入射角的增大,其散射光的偏振度也逐渐升高;材料散射光的偏振度与表面粗糙度成反比,染料型伪装材料具有较大的表面粗糙度,在与入射光的作用过程中多次散射占优,因此,其偏振度很小.利用几何光学理论分析了材料表面的偏振散射机理,分析结果与实验结论相吻合.在一定条件下,伪装材料的偏振散射特征与背景不同,偏振信息在伪装目标识别方面具有重要的军事应用价值. 相似文献
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激光脉冲进入光纤中,与光纤分子相互作用,产生Raman散射和Raylei曲散射。由于Raman散射具有温度效应,其散射光强度受温度调制,可作为温度信息的载体,用于温度解调及测温系统设计。本文提出了可行的温度解调方法及理论推导,并推导出单通道和双通道条件下的测温关系,设计出两种条件下的传感器系统。 相似文献
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A new technique for all-optical code division multiple access (CDMA) based on optical holography is described. In this technique the energy of an incoming information light signal is spread over a larger spatial domain by a two-dimensional spatial encoder which consists of patterns of (0, 1) or (1, -1). Subsequent decoding, which is obtained by a holographic filter, spatially despreads the energy of information light signal and brings it to a bright focused light spot. Experimental results obtained to demonstrate the encoding, decoding, and multiaccess capability of the proposed holographic CDMA technique are discussed and compared to other all-optical CDMA techniques. The processing gain for a holographic CDMA can be potentially as high as 106-108 , which suggests that this technique can in principle support hundreds of thousands to a few millions of users 相似文献
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提出一种用光纤传感器测量高速旋转构件微小位移量的新方法,实现了非接触式高速、高精度的位移测量。在介绍光纤传感器测量原理的基础上,得出光强与测距之间关系式。将光强转为电压信号,建立电压商值与测距之间的拟合公式。设计V带参数测量实验台,对V带稳定运转时其在轮槽中的径向位移进行测定,进而得出V带在带轮中的轨迹,测量出滑动角的大小。针对原有V带滑动角计算公式中的不足进行优化,得出新的滑动角计算公式。对比实验结果,新公式更接近实验结果,误差更小,为V带的精确设计提供理论依据。 相似文献