共查询到20条相似文献,搜索用时 78 毫秒
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线阵CCD用于长距离衍射准直测量 总被引:2,自引:0,他引:2
本文介绍了在半导体激光光纤与位相板相结合的准直情况下,利用线阵CCD探测器测量大型工件形位误差遇到的光强变化而引起测量误差的问题,并对用线阵CCD进行衍射信号测量的原理和特点作了分析。根据CCD的工作原理和特性,提出了利用自动控制CCD积分时间的方法,使CCD输出的信号峰值保持恒定,提高了系统的测量精度。 相似文献
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CCD用于全息光栅常数实时测量研究 总被引:2,自引:0,他引:2
本文讨论了在制造全息光栅过程中,CCD实时测量全息光栅常数的方法。其方法可实现高精度、全自动在线测量全息光栅常数,比传统的测量优越。文章用简单的装置借助CCD进行数据采集、数据处理,实现快速自动测量光栅常数,在全息光学中有应用价值,对推广CCD应用技术,促进光学测量现代化有现实意义。 相似文献
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CCD尺寸测量光学系统设计原理 总被引:11,自引:2,他引:9
介绍CCD尺寸测量光学系统的设计原理.重点分析远心光路中的像点弥散、一维光纤列阵照明系统及利用像点弥散斑评价CCD光学系统像质的方法。给出一种CCD测量光学系统设计实例及其像质评价结果. 相似文献
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透射光栅测量的解谱方法 总被引:5,自引:1,他引:4
对透射光栅谱仪配X射线CCD的软X射线谱测量系统TG-XCCD进行了简要描述,提出了正交函数展开法用于透射光栅谱仪配X射线CCD测量的谱回推。将正交展开法用于激光打击金盘靶的软X射线谱回推,并与迭代法的解谱结果进行了比较。结果基本一致,不对此测量系统进行了误差分析。 相似文献
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线阵CCD用于实时动态测量技术研究 总被引:19,自引:1,他引:18
本文研究的是在连续光条件下线阵CCD实时动态测量技术,除了考虑CCD像元响应非均匀性、非线性等影响因素外,还应认真考虑采样频率、测量精度、动态范围、快速电路等问题。本文还详细讨论了测量精度和动态范围问题,推导了测量精度公式与动态范围公式。为了减小测量误差和提高被测信号的频率,必须相应减小积分时间。精度公式是进行线阵CCD电路设计的基本依据公式。动态范围与频率无关,只与结构参数有关,为了充分利用CCD的动态范围,激光功率要可调。 相似文献
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本根据拉伸法测量金属杨氏模量的原理,对利用螺旋测微计测量金属杨氏模量的方法做了可行性分析,并在此基础上设计出一套完整的借助螺旋测微计测量金属杨氏模量的方法。 相似文献
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The aim of this study was to measure the shear modulus of the vocal fold in a human hemilarynx, such that the data can be related to direction of applied stress and anatomical context. Dynamic spring rate data were collected using a modified linear skin rheometer using human hemilarynges, and converted to estimated shear modulus via application of a simple shear model. The measurement probe was attached to the epithelial layer of the vocal fold cover using suction. A sinusoidal force of 3g was applied to the epithelium, and the resultant displacement logged at a rate of 1kHz. Force measurement accuracy was 20microg and position measurement accuracy was 4microm. The force was applied in a transverse direction at the midmembranous point between the vocal process and the anterior commissure. The shear modulus of the three female vocal folds ranged from 814 to 1232Pa. The shear modulus of the three male vocal folds ranged from 1021 to 1796Pa. These data demonstrate that it is possible to obtain estimates for the shear modulus of the vocal fold while preserving anatomical context. The modulus values reported here are higher than those reported using parallel plate rheometry. This is to be expected as the tissue is attached to surrounding structures, and is under natural tension. 相似文献
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针对现有光学玻璃弹性模量测量周期长、测量过程复杂等问题,提出了一种利用计算机图像处理技术快速测量小样品光学平板玻璃弹性模量的方法。基于接触力学理论和牛顿环干涉原理推导出测量光学玻璃弹性模量的解析式,利用图像处理技术的优势,通过摄像头拍摄牛顿环干涉图像,设计MFC监控与单张图片拍摄界面程序,自动测量牛顿环干涉图像中心黑斑半径,最后根据光学玻璃弹性模量与牛顿环干涉图像中心黑斑半径及牛顿环中心应力之间的关联关系,实现小样品光学玻璃弹性模量的快速测量。实验结果表明:在应力31.17 N~55.11 N范围内,光学玻璃弹性模量的测量相对误差不超过±8.8%;在应力55.11 N~71.07 N范围内,测量相对误差不超过±16%。 相似文献
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Since 1989, AFMs have been used to map the nanomechanical properties of surfaces using measurements such as force-distance curves. Quantification of the force and elastic parameters are critical to the nanomechanical analysis and positive identification of materials at the nanoscale, as well as for assessing behaviour at surfaces. In recent years, there have been AFM papers publishing “quantitative” values for the indentation modulus, however, many involved large uncertainties arising from the lack of calibration of key components, the use of manufacturers’ nominal values for these components or the use of incorrect models. This paper addresses the quantification issues in modulus measurement at surfaces for homogeneous materials using force-distance curves and how to do this with sufficient accuracy to identify materials at the nanoscale. We review the available theory and describe two routes to quantitative modulus measurement using both the AFM on its own and the AFM combined with a nanoindenter. The first involves the direct measurement of modulus using a fully calibrated instrument and allows depth analysis. The second uses indirect measurement through calibration by reference materials of known reduced modulus. For depth analysis by this second route, these reference moduli need to be known as a function of depth. We show that, using the second route, an unknown polymer may be analysed using the nanoindenter, its modulus determined and, providing the moduli of the polymers to be identified or distinguished differ by more than 20%, identified with 95% confidence. We recommend that users evaluate a set of reference samples using a traceable nanoindenter via the first route, and then use these to calibrate the AFM by the second route for identification of nano-regions using the AFM. 相似文献
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Analogy is established between the surface impedance modulus, frequency, and skin depth of inhomogeneous media on the one
hand and the fractal line length, measurement scale, and the number of measurement scales required for measuring length, respectively,
on the other hand. This analogy makes it possible to obtain frequency characteristics of the skin layer and the surface impedance
modulus independently from other methods. The frequency characteristics satisfactorily describe sedimentary and crystalline
rocks in a wide frequency range. 相似文献
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Raegen AN Dalnoki-Veress K Wan KT Jones RA 《The European physical journal. E, Soft matter》2006,19(4):453-459
We present a novel method of probing adhesion energies of solids, particularly polymers. This method uses the axi-symmetric
deformation of a thin spincast polymer membrane brought into contact with a flat substrate to probe the work of adhesion.
The use of a thin membrane minimizes uncertainty in the radius of contact, while the use of spincast films provides very smooth
surfaces by means of a very simple method. The experimental profile of the deformed membrane shows good agreement with the
expected logarithmic profile. The experimental setup enables the measurement of Young's modulus and the solid-solid work of
adhesion for thin films. The value obtained for Young's modulus of polystyrene (PS) was found to be in agreement with other
conventional measurement techniques. In addition, measurement of the work of adhesion at the PS/silicon oxide interface was
possible. The apparatus is well suited to studying the dependence of Young's modulus, work of adhesion and fracture energy
on membrane thickness, temperature, pulling rate, and ageing of the interface, and can readily be modified to study biologically
relevant samples. 相似文献
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A. Alatas A.H. Said H. Sinn C.N. Kodituwakku B. Reinhart M.-L. Saboungi 《Journal of Physics and Chemistry of Solids》2005,66(12):2230-2234
The dynamical structure factors of supercooled-liquid and hot-solid silicon are measured by inelastic X-ray scattering at the same temperature, 1620 K. Two significant changes in the averaged longitudinal sound velocities and in the longitudinal modulus are observed. First, we observe a different longitudinal modulus in the polycrystalline hot-solid silicon compared to the extrapolated value obtained from the single-crystal measurement. This reduction of the modulus may be a precursor of the semiconductor-to-metal transition. Second, the increase in the longitudinal modulus in the liquid upon supercooling is consistent with an increase in the degree of the directional bonding. 相似文献