共查询到20条相似文献,搜索用时 15 毫秒
1.
建立了一种测定化妆品中烟酰胺的紫外分光光度法。试验利用烟酰胺对紫外产生吸收的特性,以最大吸收波长为262nm,线性回归方程为A=0.02473~*C-0.00107,相关系数为R=0.99998,可以测定不同类型的化妆品的烟酰胺的含量。该方法简单易行、快速、准确,测定结果令人满意。 相似文献
2.
3.
This paper describes the first uncertainty analysis for drilling stability using a frequency-domain drilling stability model. The stability model inputs include: the modal parameters for the torsional-axial vibration mode from the twist drill-holder-spindle axial frequency response function; and the mechanistic coefficients that relate the torque and thrust force to chip area for the selected drill-workpiece material combination. Monte Carlo simulation is applied to propagate the input uncertainties to output uncertainty in the predicted stability map, which separates stable from unstable (chatter) zones in the spindle speed-chip width parameter space. The mean stability boundary and its 95% confidence intervals are determined for five cases: varying all four inputs simultaneously and varying them individually. This enables the individual sensitivities to be compared. Experimental results from drilling tests are included for comparison to the prediction. Additionally, Matlab code is provided to implement the stability model and Monte Carlo uncertainty analysis. 相似文献
4.
5.
面粉中灰分测量及其测量不确定度评估 总被引:1,自引:0,他引:1
本文对灰分测量结果不确定度进行评定。采用国标方法GB/T5 0 0 9.4 - 2 0 0 3中的重量法测定面粉中灰分1,对测量结果进行表述。本文建立面粉中灰分测量结果不确定度的评定方法 相似文献
6.
一种新的多学科系统不确定性分析方法——协同不确定性分析法 总被引:1,自引:0,他引:1
多学科设计优化中的不确定性对整个工程系统的设计过程具有非常重要的影响。对现存的不确定性定义进行比较和分类。详细描述多学科系统中的不确定性及其传播过程。在已有不确定性分析方法的基础上,提出一种新的多学科不确定性分析方法——协同不确定性分析法。该方法的基本思想是利用泰勒近似估算耦合变量和系统输出的方差,经过二次优化获得系统的稳健最优解,并对其具体计算过程进行详细描述。算例结果表明,协同不确定性分析法不仅是可行的,而且具有很高的精度,是分析多学科系统中不确定性的有效方法。 相似文献
7.
本文详细分析了能谱(EDS)定量分析过程中不确定度的来源,探讨随机变量、激发电流大小、工作距离、电子束焦距、取样点大小、电流值的可读性和电流稳定性以及ZAF因子等能谱参数对测量结果不确定度的影响。结果显示电流大小和工作距离是影响有标定量分析结果准确性的关键参数。EDS对钛非晶合金样品中Zr、Ti、Ni和Cu元素的有标定量分析结果符合定量分析要求,各元素相对扩展不确定度分别为4.68%、4.26%、5.04%和5.02%(包含因子k=2)。 相似文献
8.
吴红 《仪器仪表标准化与计量》2007,(3):34-37
一切测量结果都不可避免地具有不确定度。衡量测量结果及其质量的标准是测量结果的测量不确定度的大小。通过对工业铂热电阻的测量结果的测量不确定度的评定的分析和比较,可知测量结果的可靠程度,并可反映检测实验室的检测体系是否处于统计受控状态。进而可为产品进入国际市场奠定有利基础。 相似文献
9.
10.
11.
Uncertainty analysis for measurement of measurand 总被引:1,自引:0,他引:1
For measuring the true value of a measurand, vague statistical concept of measurand results in inefficient uncertainty analysis of measurement. The vagueness is caused by the fact that true value of the measurand is an unknown parameter such as population mean or median and the measurement of this true value is a random variable. Generally a parameter may be estimated remarkably more efficiently than the prediction of the random variable. The classical uncertainty analysis in the literature has been developed based on the structure that a measurand is a random variable. This misspecification of statistical concept costs serious price of sacrificing efficiency in terms of length of the uncertainty interval. The purpose of present study is to formally formulate a statistical model for the true value of measurand and provide an uncertainty analysis for the measurement of this true value. 相似文献
12.
13.
本文基于氧化物的ZAF修正法对典型样品进行定量分析。在得出了定量分析结果之后,分析了样品测量不确定度的来源,得出电子探针定量分析的不确定度模型,测算了每个影响因素的具体数据,最后计算出了定量结果的扩展不确定度。结果表明ZAF修正法引入的不确定度对测试结果的不确定度影响非常小,主要影响结果不确定度的因素是测量重复性引入的不确定度造成的。利用不确定度提高测试和仪器校准的准确度,可以对电子探针定量分析的后续工作提供基础和保障。 相似文献
14.
《Measurement》2016
The paper discusses the evaluation of the uncertainty of a multivariate quantity using the Law of Propagation of Uncertainty defined in the Guide to the Expression of Uncertainty in Measurement (GUM) and a Monte Carlo method according to the GUM’s Supplement 2. The quantity analysed is the electrical impedance, which is not a scalar but a complex quantity. The used measuring method allows the evaluation of the impedance and of its uncertainty in different ways and the corresponding results are presented, compared and discussed. For comparison purposes, results of the impedance uncertainty obtained using the NIST Uncertainty Machine are also presented. 相似文献
15.
紫外分光光度法测定水中N,N-二甲基乙酰胺 总被引:3,自引:0,他引:3
基于N,N-二甲基乙酰胺(DMAC)的紫外吸收光谱在190~230nm区有强吸收,建立一种紫外分光光度法测定DMAC含量的方法。在196nm处,DMAC在0~0.8%(色谱纯DMAC的1000倍稀释液所占的体积分数)范围内符合比耳定律,其R2为0.9998,实际样品测定的平均回收率为93.6%~103.5%,相对标准偏差小于2.38%。该方法的线性相关性好,操作简便、快速,适用于化纤等行业中对N,N-二甲基乙酰胺的日常检测。 相似文献
16.
17.
18.
The uncertainties obtained with a novel method for measuring power losses in transformers are examined. These uncertainties are compared with those obtained by measuring power losses as the difference between input power absorbed and output power delivered and it appears that the new method does offer certain advantages with a suitable choice of instruments. Uncertainties are evaluated in compliance with the relevant CIPM recommendation adopted in 1981 and reaffirmed in 1986. 相似文献
19.