小型微/纳米级三坐标测量机的研制

介绍一套低成本小型三维坐标测量机的研制过程，作为微/纳米级超精密测量设备，整体机台结构采用花岗岩材料；X／Y轴的移动平台利用压电材料摩擦驱动与挠性变形原理，长短两行程可达25mm范围及5nm的微位移，藉自行研发的衍射干涉激光尺，位置回馈测量系统可具有0．025nm的分辨率；测量探头在一般DVD光读取头的自动聚焦原理基础上改装，最佳分辨率可达2．5nm，该雏形机适于测量微机电组件、微型器件及膜厚等。     

微器件表面3D形貌的新型微/纳米探头测量系统

采用DVD光碟机的激光读取头,开发出微器件表面3D形貌的新型微/纳米测量系统。分析了激光读取头内部结构与运作原理,当反射面不在聚焦位置时,经四象限传感器探测聚焦误差信号(FES),驱动音圈马达以带动物镜重回聚焦位置,完成自动聚焦过程。并对音圈马达具有的磁滞现象加以研究,应用Preisach磁滞模型补偿磁滞误差,进而提高激光读取头在测量方面的精确度。结合HP激光干涉仪对测头不同测量范围的标准差与重复性进行校正测量,由校正的结果分析,此测头系统可实现微器件表面3D形貌的微/纳米测量。     

高精度微孔测量探头

对高精度探头的研究和发展进行了叙述,介绍了所研制的一款由一个二维角度传感器、一个弹性机构和一个自制的微球形钨探针组成的微孔测量探头。对探头的刚度和重复性分别进行了仿真验证和实验测试,结果表明:该探头在三维方向上的刚度均小于0.4 mN/μm,重复性均优于20 nm（k=2）。最后利用该探头对一个直径为420 μm的微孔进行了实际测量,测量结果验证了该探头的实用性。     

微纳米三坐标测量机接触扫描探头稳定性分析(英文)

对微纳米三坐标测量机(CMM)高精度扫描探头的稳定性进行了分析.该扫描探头由带有球头的光纤探针、悬浮机构、二维角度传感器和微型迈克尔逊干涉仪4部分组成.光纤探针和悬浮片固定在一起,当光纤探针的球头受到触碰时,会带动悬浮机构的悬线发生形变,进而导致贴在悬浮片上的平面反射镜倾斜或在竖直方向上发生位移,前者由二维角度传感器进行感测,后者由微型迈克尔逊干涉仪进行感测.实验结果表明,环境温度的变化是影响探头稳定性的主要因素,探头中机械结构和部件对温度变化的敏感性要远远大于探头中光电器件对温度变化的敏感性.只要将探头放到一个恒温箱中,待恒温箱温度稳定4 h再开始测量,探头即可达到1 nm的分辨力和30nm的测量标准差.     

NIM球面近场法天线校准装置的测量不确定度评定

介绍了中国计量科学研究院（NIM）开发的一套精密球面近场扫描法天线校准装置(400 MHz～110 GHz)在测量天线归一化方向图（限于幅度）时的不确定度评定。以“自我比较法”为基础,简介了探头、安装对准、数据采样和射频系统等引入的18个不确定度分量的评定结果,重点针对天线暗室反射引入的不确定度不易评估的难题,基于射线追踪法提出了一种分析、测量和计算相结合的“干扰法”。评估结果表明该套近场系统在-40 dB副瓣电平内,重复性优于0.1 dB (26 GHz)、在忽略探头极化误差时的扩展不确定度优于2.7 dB。最后分析了球面近场天线测量的不确定度特点。     

γ-CuI晶体的发光衰减时间和对X射线的能量响应

采用溶剂蒸发法生长出透明的带隙宽度为2.96 eV的γ-CuI晶体。在紫外光激发下, 该晶体在410、430 nm处分别呈现有近带边发射峰, 另在720 nm附近还出现一个与样品碘缺陷有关的宽发射带。经碘退火后, 样品720 nm发射带被基本抑制, 而在420 nm处出现了一个更强的近带边发射峰。使用扫描相机分别测量了γ-CuI晶体各发射峰(带)的衰减时间谱, 其中近带边发射峰的发光衰减时间常数均在数十皮秒量级, 表明γ-CuI晶体具有极快的时间响应特性; 而720 nm发射带的发光衰减时间常数主要在数十纳秒量级。X射线激发下, γ-CuI晶体具有435 nm近带边发射峰和680 nm发射带, 其近带边发射对X射线能量响应的测量结果表明, 当E_X<49.1 keV时, γ-CuI晶体闪烁光快分量对X射线的探测效率相对较高。     

Linnik白光干涉仪自动对焦及光程差最小化

众所周知由于两个干涉臂光路不匹配和参考镜面与被测表面的离焦,要得到相干长度非常短的Linnik白光干涉仪的干涉条纹是非常困难的.本文提出了一种自动调节的方法来解决这个问题.为了实现参考镜面和被测表面的对焦,在商用DVD读取头的基础上,对其像散法进行改进,具体方法是对和信号SS设定一个阈值,通过此阈值对归一化后的FES曲线(NFES)进行裁剪,从而获得一个与离焦距离成单调关系的曲线(TNFES),其过零点对应的就是焦点.经过实验证明,改进后的自动对焦系统的动态范围为190 μm,平均灵敏度70 mV/μm,平均标准偏差0.041 μm,分辨率4.4 nm,不确定度55 nm.此外为了最小化两个干涉臂的光程差,本文采用均方根RMSFC算法来计算成像在CCD上的干涉条纹的对比度,通过找到其最大值来最小化光程差.实验证明本文提出的自动方法可以有效地获得Linnik白光干涉仪的干涉条纹.     

接触触发式探头结构优化设计

设计了一种适用于微纳米三坐标测量机的高灵敏度接触触发式探头。介绍了该探头的结构和原理,建立了探头的灵敏度模型和刚度模型,依据三维方向等灵敏度和等刚度的原则,利用最优化方法得出了探头结构参数的最优解。对探头的刚度进行了仿真验证;分别对探头的刚度、分辨率以及稳定性进行了实验测试。实验结果表明:该探头在三维方向上的刚度均小于1 mN/μm,且近似相等;分辨率高于50 nm;当环境温度的波动范围小于±0.025℃时,探头在1.3 h内的漂移量为20nm。     

荧光量子效率绝对法测量系统校准及不确定度评定

荧光量子效率是发射与吸收的光子数之比,是表征荧光材料发光性能的关键参数。然而,用于绝对法测量荧光量子效率的光路和探测器未经校准溯源或是校准方法不当,会造成测量光谱的不准确,进一步影响荧光量子效率计算结果的不准确。采用汞氩灯对单色仪进行校准,保证了激发波长和发射波长的准确性,利用标准辐射源对光路、发射单元单色仪和探测器进行光谱相对强度校准,保证了激发波段和发射波段光谱相对强度的准确性;最后从测量模型出发,对测量不确定度进行了分析,得到在300~360nm的激发光波段和370~900nm的发射光波段内相对合成标准不确定度为3.58%,相对扩展不确定度为7.16%,k=2。通过对单色仪波长校准以及对光谱相对强度进行校准,为荧光量子效率的准确测量提供了参考。     

示波器探头校准方法探讨

示波器探头不仅是将测试信号送到示波器输入端的一个分压线路 ,而且是测量系统的一个重要组成部分 ,探头的正确使用直接关系到测量结果的准确性。在实际工作中 ,常常忽略了探头的校准 ,本文介绍了一种示波器探头的校准方法     

Intermittent process hybrid measurement system on the machining centre

This study introduces the development of a hybrid measurement system integrated on a machining centre to carry out the possible intermittent measurement of a workpiece. The developed hybrid measurement system principally consists of a MP10 touch trigger probe system, a circular triangulation laser probe system, and the measurement software. The touch trigger probe system was primarily used to measure the regular geometric features, whereas the circular triangulation laser probe system was adopted to inspect the freeform surface part of a test carrier with the help of the developed measurement software. An adjustment device consisting mainly of an adjustment unit, a joint unit, and an assembly unit, was designed and manufactured to minimize the cosine error caused by the assembly inaccuracy for the laser probe. The measuring uncertainty analysis experiments for both the touch trigger probe system and the non-contact laser probe system were investigated by using a calibrated standard sphere and the HP5529A laser interferometer system, respectively. The information in the whole measuring system – which comprised a personal computer, a CNC machining centre controller, a Renishaw MP10 touch probe system, and the controller of a Wolf & Back OTM3A20 circular triangulation laser probe system – was integrated technically. The measurement software was also developed to simulate the measuring path, prevent collision, and generate the corresponding measuring NC codes. The developed system can also be used to digitize the data points of a 3D small complex workpiece, such as a tooth model and an IC part. A carrier, combined with free form surface and regular geometric feature referred to in the ISO 10791-7 cutting test standard, was designed, manufactured and inspected in order to evaluate the performance of the developed hybrid measuring system. The measurement results of this carrier were verified through a CNC coordinate measuring machine, with satisfactory consistency. According to the measuring results, the developed hybrid measuring system was successfully and effectively used to carry out the intermittent measurement.     

飞机表面划痕非接触测量仪的研究

介绍了一种飞机表面划痕非接触测量仪。它以激光三角传感器为主要组成部件，并附以机械扫描装置，可完成被测飞机表面划痕的非接触测量。在分析了被测表面散、反射特性的基础上，给出了激光三角传感器正确放置方式，并提出改善测量精度的传感器姿态调整法。针对浅划痕测量时噪声较大的特点，提出利用子波分析的方法突出被测划痕形貌的信号处理方法，实验表明了此方法的可行性。本测量仪具有非接触测量、测量范围大、精度高、结构简单、成本较低的特点。     

用于纳米级表面形貌测量的光学显微测头

为了满足纳米级表面形貌样板的高精度非接触测量需求,研制了一种高分辨力光学显微测头。以激光全息单元为光源和信号拾取器件,利用差动光斑尺寸变化探测原理,建立了微位移测量系统,结合光学显微成像系统,形成了高分辨力光学显微测头。将该测头应用于纳米三维测量机,对台阶高度样板和一维线间隔样板进行了测量实验。结果表明：该光学显微测头结合纳米三维测量机可实现纳米级表面形貌样板的可溯源测量,具有扫描速度快、测量分辨力高、结构紧凑和非接触测量等优点,对解决纳米级表面形貌测量难题具有重要实用价值。     

Regional difference of water content in human skin studied by diffuse-reflectance near-infrared spectroscopy: consideration of measurement depth

Diffuse reflectance (DF) spectra in the 1250-2500 nm region were measured in vivo for the skin of the forehead, cheek, jaw, elbow, volar forearm, palm, knee, and heel of seven healthy volunteers, using a Fourier transform near-infrared (FT-NIR) spectrophotometer with a fiber-optic probe. Apparent regional differences of water content in the skin, as estimated from the diffuse reflectance NIR spectra, are discussed in relation to the influence of measurement depth. The NIR spectra were collected with or without a 300 microm gap between the fiber-optic probe and the skin surface. For comparison, in vitro NIR spectra of stratum corneum sheets equilibrated at 41, 50, 63, and 81% relative humidity, at 25 degrees C, were also obtained. There was a difference in the ratio of the two water bands centered near 1450 nm and 1900 nm between the contact and non-contact measurements. In addition, regional differences of water content calculated from the peak height of the 1900 nm water band, which was normalized to the peak height of the 2175 nm amide band, were compared. The results of Monte Carlo simulation indicated that the apparent regional differences arise at least in part from differences in the measurement depth due to differences in specular reflection at the skin surface and in the thickness of the stratum corneum.     

Oligodeoxyribonucleotide association with single-walled carbon nanotubes studied by SPM

Studies have been performed on both as-received and chemically oxidized single-walled carbon nanotubes (SWCNTs) grown by two different growth methods to better understand the preferential association of the oligodeoxyribonucleotide T30 (ODN) with SWCNTs. Samples of T30 ODN:SWCNT were examined under ambient conditions using non-contact scanning probe microscope (SPM) techniques. The resulting images show different morphologies ranging from tangled networks of SWCNTs to individual, well-dispersed isolated SWCNTs as the sonication time is increased. SPM images of well-dispersed, as-received SWCNTs reveal isolated features that are 1.4 to 2.8 nm higher than the bare SWCNT itself. X-ray photoemission spectroscopy (XPS) confirmed these features to be T30 ODN in nature. Chemically oxidizing the SWCNTs before sonication is found to be an effective way to increase the number of T30 ODN features.     

光电定心测头

本文介绍一种坐标测量机上使用的、用于多孔板孔心坐标测量的光电非接触式测量头。该测量头使用简便、测量迅速，其测量不确定度小于０．０１ｍｍ。     

非接触磁耦合光纤光栅位移传感器

研发了一种基于光纤Bragg光栅（fiber Bragg grating,FBG）技术的非接触磁耦合位移传感器．两块扁圆柱型硬磁铁通过软铁连接起来,形成一U型传感探头．该U型探头与被测物形成一闭合磁路,实现间隙与磁耦合力的转换,再通过一平面薄板结构将磁耦合力转变为光纤FBG的轴向应变．通过理论和实验详细地分析研究了上述两个关键技术环节．研究表明：该非接触位移传感器为一非线性传感器,非线性主要是由于磁耦合力与间隙的平方成反比这一传感器固有特性以及漏磁,特别是漏磁随间隙增加而变大造成的该非线性传感器的数据处理结果为：随机不确定度为0．23％;回程误差为0．376％;传感器综合误差为±0.606％     

Superposition of Two Dynamic Speckle Patterns

Abstract

Blood flow measurement is important in the diagnosis of circulatory disorders and the control of patient therapy. In clinical practice, a true non-contact method of measurement is advantageous because no sterilization is required and blood flow is not affected by the presence of a probe on the skin.     

Comparison of sampling techniques for in-line monitoring using Raman spectroscopy

Raman spectroscopy is currently of interest as a process monitoring tool for pharmaceutical unit operations. In this study, the performance characteristics of Raman spectrometers with different sampling optics have been investigated in the context of process monitoring, with emphasis being placed on assessing homogeneity in powder blends and following changes in solid-state form during wet granulation. A novel large spot non-contact Raman sampling device was compared with a traditional small spot size non-contact sampling device and an immersion probe. The large spot non-contact optics provided significant advantages over the standard systems both as a result of the enhanced sampling volume and because of the greater robustness of the system to fluctuations in the sampling distance during the wet granulation process.