相对压强对白炭黑氮吸附表面积测试稳定性的影响

研究相对压强对白炭黑氮吸附表面积测试稳定性的影响。结果表明:在相同液氮纯度、脱气温度、脱气时间、氮吸附点数量条件下,与相对压强范围为0.05~0.1时相比,相对压强范围为0.05~0.2时白炭黑的氮吸附表面积测量值偏低,且差值随氮吸附表面积的增大呈增大趋势;相对压强范围较小时,氮吸附表面积测试结果的线性相关因数较大,再现性较好,测试结果较稳定。     

3，5-二硝基水杨酸比色法测定淫羊藿多糖的含量

目的：建立淫羊藿多糖的含量测定方法。方法：采用3,5-二硝基水杨酸比色法（DNs法）,测定淫羊藿中的还原糖和总糖的含量,并计算出总多糖的含量。结果：DNS试剂的用量为2mL,显色温度为100℃,显色时间为5min,在520nm处多糖含量与吸光度有良好的线性关系,加样回收率为96．66％-96．74％。结论：该方法操作简便,测定结果准确,重复性好,可用于淫羊藿多糖的含量测定。     

Evaluating the measurement capability of a wheel profile measurement system by using GR&R

Reliable data with less variation play a key role for acceptance of the usefulness of the measurement output of a wheel profile measurement system (WPMS) in a railway network. However, in practice, most studies are carried out without checking the reliability of data from such a system, which may lead to inappropriate maintenance strategies. To ensure the measurement capability of WPMS and to support robust maintenance in railway systems, this study has evaluated measurement data for the flange height, flange thickness, flange slope, and tread hollowing of rolling stock wheels by using gauge repeatability and reproducibility (GR&R). In this study, acceptance and rejection criteria for the precision-to-tolerance ratio (PTR), signal-to-noise ratio (SNR), and discrimination ratio (DR) have been employed to evaluate the measurement capabilities. For the purpose of illustration, we have implemented a new proposed approach. This approach involves both an analysis using graphs with four regions with a confidence interval (CI) of 95% and an analysis using a graph with three regions with only the predicted values; the latter type of graph represents an innovation made in this study. This graph has the advantages that it can visualize three different levels of data quality in same figure, namely “unacceptable”, “acceptable” and “good”, and also include a number of measures without becoming unclear, which are features that have been missing in previous presentations. The results show that the measurements of the flange slope are on an acceptable level, while those for the flange height, flange thickness and tread hollowing have to be rejected as unacceptable. The action proposed for increasing the quality of data on the flange height, flange thickness and tread hollowing is to enhance the calibration of the WPMS. In conclusion, GR&R is a useful tool to evaluate the measurement capability of WPMS and to provide helpful support for maintenance decision making. This investigation also shows that there is good reason to be careful when selecting measures and when interpreting the results, since, for a certain wheel profile parameter, when one measure is used, the results may be acceptable, but when another measure is used, the results may be unacceptable.     

Performance evaluation of lateral flow immuno assay test kits for quantification of deoxynivalenol in wheat

Lateral flow immuno assay test kits for determining the presence of deoxynivalenol (DON) in grain provide relatively simple, cheap and quick detection means, but are only useful if they provide reliable and accurate results. This study aimed to evaluate the performance of four different lateral flow immune assay test kits, being Reveal Q+ DON (Neogen), Donsensor (Unisensor), RidaQuick DON (R-Biopharm AG), and RosaFast DON (Charm Sciences Inc.). The performance was evaluated based on accuracy, repeatability, and toxin recovery of the test kits using three types of wheat sample material. These included samples spiked at three different DON concentrations, reference material with a DON concentration of 900 μg/kg, and naturally contaminated samples with a wide range of DON concentrations.Results revealed that, in general, Reveal Q+ and Donsensor were the most accurate methods, whereas the performances of RidaQuick and RosaFast were much lower. Mean toxin recovery and repeatability of Reveal Q+ and Donsensor complied with EC requirements for analytical methods used for official control of DON in foodstuffs. Reveal Q+ and Donsensor also showed high accuracy. RidaQuick and RosaFast showed lower performance, in particular recovery of RidaQuick was lowest. However, laboratory procedures for the latter two test kits were easier to follow. In particular, RidaQuick has the easiest testing procedure and can be applied on-site without technical skills. Future research could focus on a more in-depth evaluation of the performance of Reveal Q+ and Donsensor, also including evaluation of between laboratory reproducibility.     

Quantitative evaluation of display characteristics of AMOLED displays

Abstract— Understanding the display characteristics of OLEDs is not only of general interest but also of technological importance for expanding the application of OLEDs. The display characteristics of AMOLEDs were quantitatively evaluated and compared with LCD or CRT performance. The fast response time and high contrast ratio, which are attractive characteristics of OLEDs, were also retained under low temperature and bright ambient, respectively. Moreover the luminance and color barely changed with viewing angle at any gray‐scale level. The optical design of OLED diodes is important for the emission characteristics, luminance, and color reproducibility.     

轴瓦厚度测量机稳定性的测量分析

介绍了轴瓦厚度测量系统分析计划的制订,测量系统偏倚特性、稳定性和线性分析.对测量系统的重复性与再现性分析步骤、计算过程、分析结果做了详尽的剖析与讨论.认为自行开发研制的轴瓦厚度测量机的偏倚特性、稳定性和线性能满足测量要求,其重复性与再现性指标R&R%<30%,基本上具有所需的测量能力.     

MOCVD preparation of SBTN thin films from two organometallic sources bottles

Abstract

SrBi₂(Ta_0.7Nb_0.3)₂O₉ (SBTN) films were first prepared on (111)Pt/Ti/SiO₂/Si substrates by MOCVD from only two organometallic source bottles. Bi(CH₃)₃ and the mixture of Sr[Ta(O°C₂H₅)₆]₂ and Sr[Nb(O°C₂H₅)₆]₂ were used as source materials. High compositional reproducibility was obtained; the Nb/(Ta+Nb) ratio was the same as the mixing ratio of the source. Sr/(Ta+Nb) and Bi/(Ta+Nb) ratios can be controlled by the reactor pressure and the input gas flow rate ratio of the source gases. Almost single phase of SBTN was obtained for the film deposited at 500°C and the following heat-treated at 800°C in O₂ atmosphere. Pr and Ec values of 330 nm-thick SBTN film were 8.5 μC/cm² and 91 kV/cm, respectively and were larger than those of SrBi₂Ta₂O₉ film. There was no degradation after 5x10¹⁰ cycles polarization switching.     

Impacts of spectral variations in multiwavelength excitation method on measurements of fluorescently whitened papers

The multiwavelength excitation (MWE) method for measuring the colorimetric properties of fluorescent whitening agent (FWA)‐treated specimens illuminated by a standard daylight illuminant computationally approximates not the spectral power distribution (SPD) of the illuminant but the luminescent SPD excited thereby by a weighted sum of the luminescent SPDs excited by a few different narrow‐band illuminations. The weights are optimized for the actual SPDs of those illuminations and the bispectral luminescent radiance factors of typical FWA‐treated paper specimens. Since the latter is invariant among instruments once provided as the common numerical data, the variations of the narrow‐band SPDs give major impacts to the reproducibility of this method. The weights optimized for the varied SPDs, however, mitigate the impacts. For investigating how they impact, one basic illumination system and its 16 simple variation systems were built virtually. The basic system consists of three narrow‐band LEDs and one blue‐excited white LED, whereas the individual simple variation system has either the peak wavelength or spectral width of one of the four LEDs (including the blue LED in the white LED) varied. With those systems, seven FWA‐treated papers with the known bispectral radiance factors were measured computationally by simulating the procedure of the MWE method. The differences in the colorimetric values measured with the simple variation systems from those with the basic system are far below the just noticeable difference, which indicates that the MWE method can be a practical solution for better reproducibility in measuring FWA‐treated papers.     

Gauge capability studies for attribute data

A gauge repeatability and reproducibility (R&R) method is developed to assess the capability of a measurement system. Although gauge capability studies have received substantial attention, few studies have investigated attribute data despite their wide application in industry. The primary aim of this research is to develop a procedure, based on the generalized linear model, to evaluate the R&R of a measurement system for attribute data. To calculate repeatability of a system, the procedure integrates the iterative weighted least squares (IWLS) method and deviance analysis. The proposed procedure is applied to an inclusion measurement system to verify its adequacy to model the process capability. Copyright © 2007 John Wiley & Sons, Ltd.