一种基于四象限探测器的深孔直线度测量方法的研究

介绍了以半导体激光光束为测量基准,采用四象限探测器进行深孔直线度检测的原理和方法。重点针对实际激光器近似于椭圆形状的入射光斑,推导了输出电压与椭圆光斑中心的变化规律,分析了光斑椭圆度对测量误差的影响,论证了方案的可行性与可靠性。     

四象限光电检测系统的定位算法研究及改进

在相同硬件条件下,四象限光电检测系统的线性区间和响应灵敏度等会因算法不同而产生差异。首先分析光斑定位的常用算法,通过数值积分和曲线拟合得出具有高斯分布的激光光斑位移量在不同算法下的修正曲线,设计制作了一套精度较高的数字式四象限光电定位系统,并使用该系统验证了理论推导结果。     

Employing a Cerenkov detector for the thickness measurement of X-rays in a scattering background

The variation in environmental scattering background is a major source of systematic errors in X- ray inspection and measurement systems. As the energy of these photons consisting of environmental scattering background is much lower generally, the Cerenkov detectors having the detection threshold are likely insensitive to them and able to exclude their influence. A thickness measurement experiment is designed to verify the idea by employing a Cerenkov detector and an ionizing chamber for comparison. Furthermore, it is also found that the application of the Cerenkov detectors is helpful to exclude another systematic error from the variation of low energy components in the spectrum incident on the detector volume.     

Employing a Cerenkov detector for the thickness measurement of X-rays in a scattering background

The variation in environmental scattering background is a major source of systematic errors in X-ray inspection and measurement systems.As the energy of these photons consisting of environmental scattering background is much lower generally,the Cerenkov detectors having the detection threshold are likely insensitive to them and able to exclude their influence.A thickness measurement experiment is designed to verify the idea by employing a Cerenkov detector and an ionizing chamber for comparison.Furthermore,it is also found that the application of the Cerenkov detectors is helpful to exclude another systematic error from the variation of low energy components in the spectrum incident on the detector volume.     

多面体模具角参数自动测量方法的研究

多平面冷反光镜模具质量的好坏直接影响着出射光束照度的均匀度和出射光束的定向性，目前使用的检测方法存在测量过程繁琐费时，测量精度低等缺点。本文介绍了一种利用ＣＣＤ线阵光电探测器研制的多面体模具角参数自动测量系统。该装置采用光学方法，将待测的几何参数——两相邻平面间夹角α转化为测量该两平面反射光聚焦光斑的距离，然后用ＣＣＤ图像数据采集系统处理数据。使整个系统简单、紧凑，适用范围广，对不能接触测量或因面形太小或因形状复杂而难以测量的平面夹角均可进行测量。本文亦讨论了实验数据处理，并根据实际情况，采用重心法计算光斑中心位置，使测量精度有了很大提高。最后给出了利用该系统测量的结果。     

基于侧漏型光子晶体光纤高灵敏度宽线性范围弯曲传感器的研究

基于所研制的侧漏型光子晶体光纤, 提出并研制出一种Sagnac干涉仪型高灵敏度宽线性测量范围的弯曲传感器. 实验研究结果表明, 当侧漏型光子晶体光纤中的线性缺陷与弯曲方向一致时, 采用群双折射和波谷波长偏移量测量弯曲曲率均可获得高的弯曲灵敏度, 但线性测量范围小, 且不能进行小弯曲曲率的测量. 当线性缺陷与弯曲方向垂直时, 以波谷波长偏移量进行弯曲曲率检测, 可获得10.798 nm/m^-1高灵敏度的同时且可实现0–5.03 m^-1的宽线性测量范围, 结合测量矩阵的引入可实现温度和弯曲曲率的同时测量, 进而剔除环境温度变化对弯曲曲率检测的干扰, 实现了高灵敏度宽线性范围的弯曲传感; 而以群双折射进行弯曲曲率检测, 虽然检测灵敏度较低, 但可实现对环境温度不敏感的弯曲传感. 关键词： 弯曲传感器 侧漏型光子晶体光纤 高灵敏度 宽线性范围     

提高飞秒超强激光对比度测量动态范围的一种新方法

普克尔盒(Pockelscell)和格兰棱镜以一定方式组合使用时能对超强激光脉冲的主脉冲进行消光而不会削弱预脉冲的强度,利用这一特性,文章作者设计搭建了一套高动态范围的激光纳秒对比度测量系统,利用该方法将对比度在ns量程内的动态测量范围提高了3个量级,并实验测得了2.95×10-8的纳秒对比度.     

提高飞秒超强激光对比度测量动态范围的一种新方法

普克尔盒（Pockels cell）和格兰棱镜以一定方式组合使用时能对超强激光脉冲的主脉冲进行消光而不会削弱预脉冲的强度,利用这一特性,文章作者设计搭建了一套高动态范围的激光纳秒对比度测量系统,利用该方法将对比度在ns量程内的动态测量范围提高了3个量级,并实验测得了2.95×10-8的纳秒对比度.     

热释电探测器积分响应测试系统研究

为了实现对红外探测器积分响应的自动测量,配合虚拟仪器技术搭建了一套热释电红外探测器积分响应自动测试系统。利用双绞线将测试仪器与计算机连接,以LabVIEW为开发平台编写软件测试系统,遥控测量仪器,实现计算机自动采集和处理数据实时绘制曲线,对LT-020-H型热释电红外探测器在不同调制频率下的积分响应度进行了测试并分析。在500K的黑体辐射下,探测器积分响应度达到3.5×106V/W。通过对实验结果进行分析,得到了探测器响应、黑体辐射温度以及信号调制频率之间的关系。     

A clinical procedure for linear measurement at the vocal fold level

The relatively narrow depth of field and long focal distance of the microscope are the basic facts on which the procedure is founded. To the microscope a videocamera is connected. As long as the adjustments of the microscope are unchanged and your recordings are made in focus you can compare sizes and determine the magnification factor and thus obtain real sizes. The maximal error of measurement is calculated: 4.65 ± 3.10%.     

基于多重分形去趋势波动分析法的交通流多重分形无标度区间自动识别方法

无标度区间是时间序列在统计意义上存在分形自相似性的尺度范围,是交通流多重分形特征研究中的重要组成部分.为解决交通流多重分形研究中多重分形去趋势波动分析法(multi-fractal detrended fluctuation analysis,MF-DFA)缺乏有效识别无标度区间方法的问题,本文在分析算法过程中交通流波动函数对数曲线突变点性质的基础上,结合传统无标度区间识别方法的构建思想,建立基于MF-DFA算法的无标度区间自动识别方法.以北京市二环快速路外环方向的部分道路为例开展实例研究,通过与传统无标度区间识别方法的结果对比,验证新方法的有效性.研究结果表明:本文方法能自动识别交通流多重分形无标度区间,且稳定性好;案例研究可知交通流短时间内波动较小、自相似性较强,随着研究时间段变长、交通流波动逐渐变大,自相似性逐渐消失,进一步解释了交通流无标度区间的有限性.     

Design and experimental verification of novel six-degree-of freedom geometric error measurement system for linear stage

In this study, a novel and simple measurement system for simultaneously measuring the geometric errors in six-degree-of-freedom (6-DOF) for a moving linear stage of a machine tool is designed and validated. Compared to laser interferometer and laser Doppler systems, this new measurement system is less expensive and capable of multiple functions. The proposed measurement system comprises an optics module, composed of two reflectors and two cubic beam splitters; a sensing module, composed of three two-dimensional position sensitive detectors (PSDs); and a helium-neon (He-Ne) laser. Using skew-ray tracing and a first-order Taylor series expansion, the 6-DOF geometric errors of the moving linear stage, which include translation and rotation errors, are analyzed. A laboratory prototype system is built to verify the effectiveness and accuracy of the proposed measurement system. The experimental results show that the displacement uncertainty and the angular uncertainty of the proposed measurement system are less than 1.2 µm and 0.4″, respectively. Compared with the Renishaw laser interferometer XL-80 laser system, the translational accuracy and the rotational accuracy of the proposed measurement system are less than ±1 µm and ±0.2″, respectively, when the linear stage travels 6 mm.     

Vector fuzzy control iterative algorithm for the design of sub-wavelength diffractive optical elements for beam shaping

The vector fuzzy control iterative algorithm (VFCIA) is proposed for the design of phase-only sub-wavelength diffractive optical elements (SWDOEs) for beam shaping. The vector diffraction model put forward by Mansuripur is applied to relate the field distributions between the SWDOE plane and the output plane. Fuzzy control theory is used to decide the constraint method for each iterative process of the algorithm. We have designed a SWDOE that transforms a circular flat-top beam to a square irradiance pattern. Computer design results show that the SWDOE designed by the VFCIA can produce better results than the vector iterative algorithm (VIA). And the finite difference time-domain method (FDTD), a rigorous electromagnetic analysis technique, is used to analyze the designed SWDOE for further confirming the validity of the proposed method.     

相位物体的相位检测分析方法

介绍了相位物体的相位检测方法,包括传统的暗场法、纹影法和相衬法,重点介绍基于图像处理的相位物体的双点源光束干涉测量与扫描成像方法,并比较它们的优缺点,同时对目前的研究进展进行了综述.     

Non-contact acoustic method for the simultaneous measurement of thickness and acoustic properties of biological tissues

The frequency dependence of the magnitude and phase shift of reflected waves from a thin tissue specimen has been found to yield characteristics patterns as a function of the specimen thickness. By analysis of those characteristic patterns, the specimen thickness can be determined so that the attenuation constant and the sound speed can be obtained by a non-contact procedure. The method is demonstrated in the frequency range 100 MHz to 200 MHz, using a scanning acoustic microscope and approximately 10 μm thick myocardial tissue samples of human origin, one paraffin embedded.     

水听器线列阵近场声压测量误差实验研究

本文介绍了用于近场声压的测量水听器中阵元水听器测量声压的可靠性检验方法和实验结果,提出了元水听器测量球面波场中声传播衰减的曲线与现想球面波声场中场传播衰减的曲线对比的检验,要用球面声源声中心测量值对收发距离进行修正的方法,实验水池中对线列阵上十元水吸器在球形声源水池中进行了传播衰减曲线的测量分析,验证了基阵的弱散散射性能,表明线阵可用于距离小至1／7波长的极近场的扫描测量。     

复杂刚性运动物体的高精度三维测量算法

基于相移法的三维形貌重建精度高,对环境噪声和阴影等不敏感,但由于多幅条纹解相位,难以应用于动态物体的三维测量中,为此,提出了一种新的算法.基于Harris算法提取刚性运动棋盘格的角点,确定相邻两帧采集条纹图像之间的像素偏差并校正采集条纹图像;根据投影仪和摄像机的标定参数建立投影图像和采集图像之间的空间变换矩阵,并根据变...     

双激光器实时测量机翼变形的误差分析

基于双激光器测量机翼弹性变形量的理论模型,应用误差分析理论,分析了飞机在飞行过程中双激光器测量方法的误差。以激光器的原始测距误差为出发点,依据误差传递公式,分析了测量机翼变形量的绝对误差和相对误差,并给出了计算仿真结果和相应的图形。研究结果对机载毫米波综合孔径成像系统的图像校正和相位补偿、机载导弹挂飞试验等具有及其重要的应用价值。     

Feasibility study for the measurement of Bc meson mass and lifetime with the general purpose detector at the LHC

In this paper a feasibility study of the Bc meson to measure its mass and lifetime is described with the general purpose detector at the LHC.The study solely concentrated on the J/Ψπ+,J/Ψ→μ+μ- decay channel of the Bc and it was concluded that about 120 events can be selected in the first fb-1 of data.With this data sample,the mass resolution was estimated to be 2.0(stat.) MeV/c2 while the cr resolution was found to be 13.1(stat.) μm,I.e.the lifetime resolution to be 0.044(stat.) ps.     

三维形貌检测中自动参考栅技术的改进

通过对形貌检测中理论参考面相位分布规律的分析 ,对三维形貌轮廓术中参考面相位自动生成技术进行了研究。利用采集的待测物体栅线图样中未变形区域对应相位信息 ,通过最小二乘迭代法数据拟合 ,获得理想参考面相位分布参数 ,也就是获得理想参考面上的相位分布。由于不需另外采集实物参考面变形光栅图像 ,不仅减少了实物参考面的采集步骤 ,而且不需要对实物参考面相位进行求解 ,这样就可以真正实现只采集一幅图像解调形貌 ,从而提高测试速度 ,同时还可避免由于采用实物参考面而存在的误差 ,使得求解兼有理想参考面方法与实物参考面方法的优点。利用改进的方法对塑胶小熊猫面具进行了实际测量 ,给出了测试结果