光学玻璃的折射率测定

本文介绍测定光学玻璃的折射率用的两种仪器的设计。制造光学玻璃的生产单位必需有两种测定折射率的方法。这些方法是:(1)给出折射率的精度为±1×10^-5的快速和精确的方法,和(2)能得到±1×10^-6的较精确的系统。介绍的第一种方法是光电 V 块系统,而第二种是利用电子条纹计数的双光束干涉系统。     

入射角度变化对角锥棱镜测量精度的影响

为了掌握角锥棱镜用在激光跟踪仪中光束入射角度变化对其测量精度的影响规律。详细分析了角锥棱镜的工作原理和反射特性。计算出了角锥棱镜在不同入射角下的实际有效反射面积,并建立了角锥棱镜有效反射面积随光束入射角度变化的理论公式,进而得到角锥棱镜测量精度随光束入射角度变化的规律。实验结果表明：角锥棱镜测量精度随入射角增大而减小,在最大允许入射角处发生突变。在最大允许入射角±35.26°时其测量误差达到0.050mm;而在±20°范围内时其测量精度优于0.010mm,且入射角度在±15°范围内其测量精度最高,稳定性最好。所得结论证明了当角锥棱镜在入射角度为±20°范围内工作时能满足了激光跟踪仪的测量精度要求,这对角锥棱镜设计和实际测量工作具有指导意义。     

GDV—1型光电V棱镜折光仪研制成功

我国第一台 GDV—1型光电 V 棱镜折光仪在沈阳仪器仪表工艺研究所研制成功,于1984年3月17日在沈阳由机械工业部仪表局主持召开全国行业鉴定会,并通过了鉴定。参加鉴定会的有15个单位,20名代表。代表一致认为:该折光仪,采用了先进技术,提高了仪器测量精度,扩大了折射率波长测量范围。它的研制成功,填补了我国光学玻璃折射     

折射率温度系数测定仪中数据自动采集处理系统的研究

本文介绍了折射率温度系数测定仪的数据自动采集系统。研究了用微计算机对能量及周期均有变化状态下,干涉条纹随温度变化量的采集及处理的硬件及软件。实验中干涉条纹测量精度达±0.06。温度测量精度达±0.5℃。满足了折射率温度系数达±6×10^-7/℃的精度要求。     

高精度光谱辐射计测量超低光谱透过率

设计并研制了一种基于光栅双单色仪的高精度全自动单光束光谱辐射计。该仪器主要由高稳定氙灯、带有快门的单光阑屏、石英透镜、中性减光片、紫外光栅双单色仪、光电探测器及电控系统组成,测量光谱范围为200~400 nm, 可以实现10^-6~10^-8量级光谱透过率高精度测量,测量过程由自行编制的计算机软件进行自动控制,能实现全自动单光束测量。给出了该仪器的测量原理、测量方法及数据处理方法。利用该仪器测量了紫外滤光片样品的光谱透过率,分析了测量不确定度。实验结果表明,该仪器测量精度高、速度快、测量合成标准不确定度＜3.16×10^-3,完全满足测量精度要求,可应用于对精度要求高的紫外滤光片光谱透过率的测量。     

一种光学玻璃折射率自动测量方法

本文研究了一种折射率自动测量方法。可对紫外、可见,红外光谱折射率作自动精密测量。在光源稳定情况下,可见光测量精度可达±3×10^-6。该方法以最小偏向角方法为依据,以外反射像引导接收器,使其自动跟踪至最小偏向角的精确位置,最后给出样品的折射率。整个测量系统采用微计算机完成自动控制、采集及处理。该方法还可进行角度自动测量。     

利用Fizeau干涉仪测量激光波长

采用Fizeau干涉仪测量激光波长,测量的重复精度为5×10^-7.     

折射率自动测试中的误差

高精度、宽光谱自动折射仪是采用垂直底边入射,对称折射的方法,对等边三棱镜样品的三个顶角进行封闭测量,以提高测试精度。本文对光束平行度,准直光与底边垂直度、样品加工角度差、测角精度、瞄准精度等诸因素所产生的误差进行了分析及计算。给出了折射率的测试不准确度。在可见及近红外光谱区:△N≤±3×10^-6。文中还对该测试方法与最小偏向角方法进行了比较,并以实测数据证明了两种方法具有同样的测试精度。     

数字波面干涉仪测试光学材料均匀性

本文叙述了一种不受干涉仪系统误差及试样加工误差限制的测试光学材料均匀性的方法。借助于电子计算机,通过对四张干涉图的分析与处理,可以精确计算不包括线性变化的折射率偏差及厚度偏差。给出了两块玻璃的测试结果,并进行了测量精度的分析,对25mm厚的玻璃,精度为4×10^-7。     

自动Ⅴ棱镜折射仪

自动V棱镜折射仪主要用于玻璃、晶体等固体和液体材料折射率、色散系数和部分色散精密测量,与传统的目视V 棱镜折射仪相比,具有精度高、自动测量、自动计算和自动打印测量结果等特点,同时排除了目视测量引起的主观误差,提高了工作效率。仪器采用了一种新颖的总体结构方案,并且应用了微机技术,圆光栅测角技术、光电瞄准技术和自动寻的技术等近代科学技术,从而研制出一种操作方便、性能稳定,具有实用价值的国内外第一台自动V 棱镜折射仪。仪器测量光谱范围为400～750nm 内的七条主谱线折射率;可测量折射率范围1.3～1.95(在此范围之外精度降低);仪器的测量精度优于±1.5×10~(-1.5)。     

一种测量高质量光学玻璃均匀性的新方法——合干涉图法

本文介绍的是能够定量测出高质量光学玻璃均匀性的合干涉图法.该方法能够同时测量出均匀性的线性及非线性变化量,且操作过程比全息法大大简化.测量精度为±1×10^-6.     

超低透过率的测定

本文介绍了用波长为632.8nm的He—Ne激光器作为光源测量透射比小于10^-7/cm²的X光滤光片针孔透射比的方法。为了测量这样低的透过率,我们设计和安装了反射式超低透过率测定装置。用黑色玻璃作为反射式衰减元件,用光电倍增管作为接收器,用数字电压表作为读数仪表。同时,还用中性玻璃滤光片组作为透过式衰减器,也测量了超低透过率。两种方法都得出满意的结果。     

用X射线反射测量法表征双层结构中 低原子序数材料的特性

介绍了用X射线反射测量术表征双层薄膜中低原子序数材料特性的方法。由于低原子序数材料的光学常数与Si基板材料的光学常数非常接近,用X射线反射法确定镀制在Si基板上的低原子序数材料膜层结构的变化十分困难,因此,提出了在镀制低原子序数材料前,首先在基板上镀制一层非常薄的金属层的方法。实验中,选用Cr作为金属层材料,制备并测试了三种不同C膜镀制时间的Cr/C双层薄膜。反射率曲线拟合结果表明,C膜密度约为2.25 g/cm³,沉积速率为0.058 nm/s。     

Effects of the number of pulse repetitions and noise on the velocity data from the ultrasonic pulsed Doppler method with different algorithms

The ultrasonic pulsed Doppler technique known as the ultrasonic velocity profile (UVP) method has been widely used in many engineering fields. The analysis algorithms of the UVP, the number of pulse repetitions (N_pulse), noise and reflector conditions, etc. all affect the measurement accuracy. N_pulse is related to the temporal resolution, thus to improve this resolution it must be set as low as possible. However, it is known that the measurement accuracy of the instantaneous velocity becomes worse with decreasing values of N_pulse. In this study, UVP analysis algorithms including the fast Fourier transform (FFT), autocorrelation, and the wavelet transform (WT) were compared via simulations and experiments using varying values of N_pulse and the signal-to-noise ratio (SNR). We show that there is an appropriate N_pulse for each algorithm that depends on the SNR; specifically, the value of N_pulse increases with decreasing SNR. The difference between the algorithms for the velocity data was small under low noise conditions. However, a FFT with a Gaussian interpolation produced the best result under noisy conditions. In contrast the WT was relatively unaffected by noise. Therefore, a WT is the preferred choice for measuring velocity distributions if high sampling measurement is not required.     

利用自校正原理提高光电传感器的测量精度

本文分析了光电式传感器在模拟式工作状态下难于实现高精度测量的原因，提出了通过自校正提高测量精度的方法。通过卷绕式连续真空镀膜膜厚测量的实例，证明效果良好。     

Assessment of local deformation using EBSD: Quantification of accuracy of measurement and definition of local gradient

Electron backscatter diffraction (EBSD) in conjunction with scanning electron microscopy was used to assess the magnitude of microstructural scale deformation (local deformation) for deformed Type 316 stainless steel. Local misorientation, which is an averaged misorientation between neighboring measurement points, is often used for assessment of local deformation. However, the local misorientation is unsuitable for a quantitative evaluation because it depends not only on the local deformation but also on various factors such as measurement accuracy and the distance between points used in the misorientation calculation (step size). In this study, first, the measurement accuracy was quantified by a parameter called background noise. The factors which affect the measurement accuracy were then discussed from measurements under various conditions. Secondly, in order to reduce the influence of measurement conditions and exclude the dependency of step size in the local deformation assessment, a parameter called the local gradient G_L was proposed. The local gradient clearly showed the spatial distribution of local deformation regardless of the measurement accuracy, and it had hardly any effect from grid pattern and step size. Finally, the local gradient was correlated with the plastic strain from which it was revealed that the strain gradient near a notch root could be estimated by the EBSD measurement.     

Investigations on pressure dependence of Coriolis Mass Flow Meters used at Hydrogen Refueling Stations

In the framework of the ongoing EMPIR JRP 16ENG01 “Metrology for Hydrogen Vehicles” a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70 MPa HRS regarding mass flows (up to 3.6 kg min⁻¹) and pressures (up to 87.5 MPa).