火花放电原子发射光谱仪分析高含量硅时校准曲线的扩展与应用

火花放电原子发射光谱仪分析高含量Si(w(Si)≥3.0%)时,其元素含量已超出了校准曲线的线性范围,导致分析值偏低。实验通过增加中低合金钢、硅钢标准样品,完善并扩展了Si校准曲线,完成了共存元素的干扰校正,拓宽了Si元素的分析范围,质量分数上限由3.14%扩展至4.16%,线性相关系数达0.99965。校准曲线扩展后重新选择标准化样品进行漂移校正,校准曲线强度比由9.41扩展至11.01。对扩展含量段的两个样品(w(Si)≥3.0%)进行精密度考察,结果的相对标准偏差(RSD,n=10)为0.43%和0.50%;对比了8个不同Si含量的样品,发现完善、扩展后校准曲线的Si测定值与认定值更相符;同时统计过程控制(SPC)控制图处于受控状态。可见校准曲线经完善、扩展后可满足工艺过程控制和成品分析要求。     

光学显微定位系统定位精度分析

为了提高光学显微定位系统对细胞微生物识别定位的精度：一方面，必须改进手眼标定方法；另一方面，需要提高全局图像识别的准确性，因此，提出一种两步法对系统进行手眼标定。首先，通过标定固定靶标来确定系统原点，并得到视觉模块相对于系统原点的转换关系；然后，根据每次拍照的起始点位置、拍照的数量和移动的步长求解出全局图像相对于系统原点的转换关系；最后，为了进一步提高全局转换关系的准确度，提出一种基于傅里叶变换的误差矫正方法，利用傅里叶变换求解出视觉模块在移动过程中的误差，并加入系统进行补偿。实验结果表明，误差补偿之后，系统X轴方向的误差均值从10.23 μm降为-0.002 μm，Y轴方向的误差均值从6.9 μm降为-0.50 μm，显微定位系统的平均定位精度达到了99%以上。结果表明，所提方法可很好地用于光学显微定位系统对细胞微生物进行高精度的自动化抓取。     

工艺尾气氚测量装置的研制

通过选择装置材料、优化结构及参数,设计制作了有效体积为11.0 mL的测氚电离室,用于工艺尾气中氚含量的测量。用质谱法标定绘制了工作曲线,工作曲线线性范围为0.013 4%～0.168%(体积)。测试表明:装置泄漏率为5.5×10^-7 Pa·m³/s,密封性良好;本底电流为2.98×10^-14A;装置探测下限值为1.35×10^-4 %(体积);变异系数≤1.50%;仪器响应时间≤10 s,响应速度快,测量周期短,满足工艺样品的检测需求。     

Relative spectral response calibration using Ti plasma lines

This work introduces the branching ratio(BR) method for determining relative spectral responses,which are needed routinely in laser induced breakdown spectroscopy(LIBS). Neutral and singly ionized Ti lines in the 250–498 nm spectral range are investigated by measuring laser-induced micro plasma near a Ti plate and used to calculate the relative spectral response of an entire LIBS detection system. The results are compared with those of the conventional relative spectral response calibration method using a tungsten halogen lamp, and certain lines available for the BR method are selected. The study supports the common manner of using BRs to calibrate the detection system in LIBS setups.     

Standardization of milk infrared spectra for the retroactive application of calibration models

The objective of this study was to standardize the infrared spectra obtained over time and across 2 milk laboratories of Canada to create a uniform historical database and allow (1) the retroactive application of calibration models for prediction of fine milk composition; and (2) the direct use of spectral information for the development of indicators of animal health and efficiency. Spectral variation across laboratories and over time was inspected by principal components analysis (PCA). Shifts in the PCA scores were detected over time, leading to the definition of different subsets of spectra having homogeneous infrared signal. To evaluate the possibility of using common equations on spectra collected by the 2 instruments and over time, we developed a standardization (STD) method. For each subset of data having homogeneous infrared signal, a total of 99 spectra corresponding to the percentiles of the distribution of the absorbance at each wavenumber were created and used to build the STD matrices. Equations predicting contents of saturated fatty acids, short-chain fatty acids, and C18:0 were created and applied on different subsets of spectra, before and after STD. After STD, bias and root mean squared error of prediction decreased by 66% and 32%, respectively. When calibration equations were applied to the historical nonstandardized database of spectra, shifts in the predictions could be observed over time for all investigated traits. Shifts in the distribution of the predictions over time corresponded to the shifts identified by the inspection of the PCA scores. After STD, shifts in the predicted fatty acid contents were greatly reduced. Standardization reduced spectral variability between instruments and over time, allowing the merging of milk spectra data from different instruments into a common database, the retroactive use of calibrations equations, or the direct use of the spectral data without restrictions.     

The Bulk Production Of Colour Prints

Some indication of the use of Phenidone in PQ developer systems in large scale motion picture laboratory practice is given. Various characteristics, which were examined on a plant scale before MQ systems were abandoned in favour of PQ systems, are discussed; the stabilities and economics of the two systems are compared.     

An empirical study on the quantitative notion of task difficulty

Most Adaptive and Intelligent Web-based Educational Systems (AIWBES) use tasks in order to collect evidence for inferring knowledge states and adapt the learning process appropriately. To this end, it is important to determine the difficulty of tasks posed to the student. In most situations, difficulty values are directly provided by one or more persons. In this paper we explore the relationship between task difficulty estimations made by two different types of individuals, teachers and students, and compare these values with those estimated from experimental data. We have performed three different experiments with three different real student samples. All these experiments have been done using the SIETTE web-based assessment system. We conclude that heuristic estimation is not always the best solution and claim that automatic estimation should improve the performance of AIWBES.     

Identifying the Magnitude and Location of a Load on a Slender Beam Using a Strain Gauge Based Force Transducer

A unique strain gauge based method is developed to identify the magnitude and location of a load on a slender beam with variable cross sections, and pinned, firm rest, soft rest, pinned‐fixed, and fixed boundary conditions. Four uniaxial strain gauges are mounted to the bottom surface of the beam, and the bending moment diagram of the beam can be constructed using measured strains on the beam. By combining individually scaled strain gauge outputs, the magnitude and location of the load can be accurately identified. The strain gauge based force transducer methodology is experimentally validated on prismatic beams with firm rest, soft rest, firm rest‐fixed, and fixed boundary conditions, and a continuously tapered beam with rest boundary conditions. The force transducer methodology is independent of the boundary conditions of the beam, and the error from strain gauge drift due to uniform thermal expansion on a prismatic beam can cancel out.     

Long Term Change in Level-Volume Relation of an Accountability Tank for Plutonium Nitrate Solution

A slight change in the level-volume relation for an accountability tank for a large amount of plutonium nitrate solution (PuN) was observed at the Plutonium Conversion Development Facility (PCDF) in the Power Reactor and Nuclear Fuel Development Corp. (PNC), Tokai Works. From the results of annual tank re-calibrations for the plutonium receiving tank from 1985 to 1992 using the incremental feed of nitric acid as the density standard, it became clear that the relation between the level and the volume changed slightly, and the rate of the change was a linear function of operating time. Also it became clear that the change was linear in relation to the level. In the PCDF, the cumulative change in the volume at the nominal level was evaluated to be 0.1% during 8 years' operation. It was also evaluated that the repeatability of the re-calibration is much better than 0.1%. A reasonable frequency of tank re-calibration is once every 5 years.     

The proof of a better performance by one-stage than two-stage estimation in robot calibration

Calibration of a robot manipulator requires an external instrument to measure its end-effector locations. If the parameters are estimated directly from the measurements, it is called one-stage estimation. Otherwise, it is called two-stage estimation. It was previously observed that two-stage estimation has the drawback of error propagation. Theoretically, it is known that for linear system, the minimum variance is achieved using the best linear unbiased estimator in one-stage estimation. However, the two-stage estimation can also achieve the minimum variance under certain conditions. In this paper, the statistical properties of both are explored in detail under a newly established mathematical fact. The result can be extended to the nonlinear estimation problem via approximation. Simulations of robot calibration by a coordinate measuring machine and eye-in-hand camera are conducted and the results confirm the theoretical analysis.