粘质沙雷氏菌测量方法研究

粘质沙雷氏菌是生物防护评价的指示菌。对粘质沙雷氏菌营养琼脂平板涂布法进行了方法验证和协同实验验证以及不确定度分析。结果显示,该方法重复性和复现性均较好,室内重复性相对标准偏差为8.93%,室间相对标准偏差为14.95%。经统计分析,营养琼脂平板涂布法相对扩展不确定度为12.60%（k=2）,适用于粘质沙雷氏菌定量测量。     

枯草芽孢杆菌黑色变种芽孢测量方法研究

枯草芽孢杆菌黑色变种芽孢是生物防护和灭菌效果评价的重要指示微生物,其量值准确可以保证评价的有效性和可比性。对枯草芽孢杆菌涂布平板法进行了方法验证和协同实验验证以及不确定度分析。结果显示,当平板上的菌落数在30～300CFU之间时,该方法重复性和再现性均较好,室内重复性相对标准偏差为10.0%,室间相对标准偏差为14.1%。经统计分析,胰蛋白胨大豆琼脂培养基平板涂布法相对扩展不确定度为12.0%(k=2),适用于枯草芽孢杆菌黑色变种芽孢定量测量,对于人员防护装备防护性能评价、消毒剂检测及灭菌质量控制具有重要意义。     

红外测油仪用标准物质的研制

为保证分析测量结果的准确可靠,研制了浓度为1000μg/mL的红外测油仪用溶液标准物质。以称量-容量法制备,计算结果定值,对原料进行了纯度分析、制备方法控制,考察了样品均匀性和稳定性,评定了所配制标准物质浓度定值的不确定度。通过与GBW(E)130171比对,验证了标准物质的定值结果准确可靠,相对扩展不确定度<2%(k=2),有效期限为12个月。该标准物质已被批准为国家二级标准物质。     

甲醇纯度国家一级标准物质的研制

介绍了甲醇纯度标准物质的研制方法,采用国际基准方法之一的凝固点下降法对该标准物质进行了定值,利用气相色谱法对定值结果进行了验证,同时对该标准物质进行了均匀性检验和稳定性考察.甲醇纯度标准物质定值结果为99.7%,扩展不确定度为0.3%.其均匀性和稳定性检验结果表明,该标准物质符合国家一级标准物质的技术要求.     

异辛烷中的正十六烷标准物质的研制

介绍了异辛烷中正十六烷标准物质研制方法。采用称量-容量法对该标准物质定值,利用气相色谱法对定值结果进行了验证,同时考察了该标准物质的均匀性和稳定性,并与中国计量科学研究院研制的标准物质GBW(E)130102进行比对,标准物质定值结果为100ng/μL,相对扩展不确定度为3%(k=2),有效期为1年。该标准物质已成功取得国家二级标准物质证书,证书编号为GBW(E)130494。     

氯化钾电导率溶液标准物质的研制

介绍了氯化钾电导率溶液标准物质的研制方法,采用与一级标准物质比较定值的方法对该标准物质进行了定值,利用高精度电导率仪对定值结果进行了验证,同时对该标准物质进行了均匀性检验和稳定性考察。氯化钾电导率溶液标准物质的定值结果为1408μS/cm,扩展不确定度为:Urel=0.6%,k=2。其均匀性和稳定性检验结果表明,该标准物质符合国家二级标准物质的技术要求。     

阴沟肠杆菌定量标准物质的研制

采用真空冷冻干燥法和滤膜法定值技术,研制了球状的阴沟肠杆菌定量标准物质。经保护剂配方及冻干程序参数优化后,阴沟肠杆菌的平均存活率达51%,形状均匀一致、外观光滑无塌陷,能完全复水速溶。通过结晶紫中性胆盐琼脂培养基平板计数法考察均匀性和稳定性,证明该标准物质均匀性良好,-80 ℃至少可稳定保存6个月。该标准物质由6家实验室采用滤膜法联合定值,经不确定度评定,标称值为（2.0±0.1）log10 (cfu/瓶),相对扩展不确定度为10%(k=2)。标准物质中阴沟肠杆菌活菌数含量水平为10² cfu/瓶,可以直接溶解使用,无需稀释,使用方便,同时减少了测量不确定度来源。     

牛肝标准物质中氯含量的定值方法研究

针对基体标准物质中氯含量的准确定值问题,采用高温燃烧水解-离子色谱法和干灰化-电位滴定法对牛肝标准物质中的氯含量进行了测定。对两种方法的前处理和测定条件进行了优化,实验结果表明两种方法的测定结果一致,测定结果的相对标准偏差分别为0.7%和1.1%。采用NIST牛肝标准物质(SRM1577c)对两种方法进行了验证,两种方法的测定结果与标准值相符。对两种方法测定结果的不确定度进行了评定,氯测定结果的相对扩展不确定度(k=2)分别为1.6%和2.2%。两种方法测定牛肝中氯含量都准确可靠,能够满足标准物质定值的要求。     

瓶装氮气中22组分挥发性卤代烃混合气体标准物质的研制

介绍瓶装1μmol/mol氮气中22组分挥发性卤代烃混合气体标准物质的研制过程。以22种挥发性卤代烃高纯试剂为原料,采用称量法制备并计算定值,评定制备过程引入的不确定度、以及均匀性和稳定性引入的不确定度,并将研制的标准物质送至中国计量科学研究院进行测试比对,采用En值评定比对结果,结果显示En值均1,所有组分比对结果判定均为满意,验证研制标物定值结果的准确性。该气体标准物质获得国家二级气体标准物质证书,编号为GBW(E)062232,其定值的相对扩展不确定度为U=5.0%(k=2),有效期限为12个月。     

酸性橙II纯度标准物质的研制

质量平衡法是确定有机类标准物质纯度的经典方法,利用质量平衡法研制了GBW(E)100373酸性橙Ⅱ纯度标准物质,介绍了标准物质样品的制备、均匀性检验、稳定性检验、定值、不确定度评定及比对和验证等严格的研发程序。最终获得了纯度认定值为99.2%,相对扩展不确定度为1.0% (k=2)的酸性橙II纯度标准物质,可以在食品和化妆品分析中的仪器校准和方法评定等领域发挥重要作用。     

卷烟条包装盒压痕挺度测量不确定度的评定

目的以卷烟条包装盒为研究对象,依据YC/T 330测定卷烟条包装盒的纵、横向压痕挺度,分析由折痕挺度仪、试样裁切尺寸偏差及测量重复性所引入的测量不确定度值,从而得到卷烟条包装盒压痕挺度的测量不确定度。方法通过对压痕挺度进行10次独立重复性试验,由计算标准偏差得出标准不确定度值,也称A类不确定度;然后再按B类不确定度评价方法对测量仪器及取样尺寸偏差带来的不确定度进行计算,得出B类不确定度;计算合成不确定度;最后计算扩展不确定度。结果依据YC/T 330测定卷烟条包装盒A的扩展不确定度U_纵=(83.1±6.22)g,k=2;U_横=(59.7±4.20)g,k=2。结论通过评定结果可知,对不确定度影响分量由大到小依次为试样裁切尺寸偏差、测量重复性、折痕挺度仪校准参数。     

原子吸收法测定酱油中铅不确定度的评定

通过对测定酱油中铅含量的不确定度评定分析,找出不确定度产生的主要因素,评定确认最小二乘法拟合校准标准曲线及测量重复性是影响结果的最主要因素,使用标准物质(标准储备液)及稀释过程引入的不确定度也应引起重视,此方法对类似的火焰原子吸收法测定样品中待测元素含量有借鉴和参考作用。     

MEMS Young’s Modulus and Step Height Measurements With Round Robin Results

This paper presents the results of a microelectromechanical systems (MEMS) Young’s modulus and step height round robin experiment, completed in April 2009, which compares Young’s modulus and step height measurement results at a number of laboratories. The purpose of the round robin was to provide data for the precision and bias statements of two \ related Semiconductor Equipment and Materials International (SEMI) standard test methods for MEMS. The technical basis for the test methods on Young’s modulus and step height measurements are also provided in this paper.Using the same test method, the goal of the round robin was to assess the repeatability of measurements at one laboratory, by the same operator, with the same equipment, in the shortest practical period of time as well as the reproducibility of measurements with independent data sets from unique combinations of measurement setups and researchers. Both the repeatability and reproducibility measurements were done on random test structures made of the same homogeneous material.The average repeatability Young’s modulus value (as obtained from resonating oxide cantilevers) was 64.2 GPa with 95 % limits of ± 10.3 % and an average combined standard uncertainty value of 3.1 GPa. The average reproducibility Young’s modulus value was 62.8 GPa with 95 % limits of ± 11.0 % and an average combined standard uncertainty value of 3.0 GPa.The average repeatability step height value (for a metal2-over-poly1 step from active area to field oxide) was 0.477 μm with 95 % limits of 7.9 % and an average combined standard uncertainty value of 0.014 μm. The average reproducibility step height value was 0.481 μm with 95 % limits of ± 6.2 % and an average combined standard uncertainty value of 0.014 μm.In summary, this paper demonstrates that a reliable methodology can be used to measure Young’s modulus and step height. Furthermore, a micro and nano technology (MNT) 5-in-1 standard reference material (SRM) can be used by industry to compare their in-house measurements using this methodology with NIST measurements thereby validating their use of the documentary standards.     

Uncertainty Due to Finite Resolution Measurements

We investigate the influence of finite resolution on measurement uncertainty from the perspective of the Guide to the Expression of Uncertainty in Measurement (GUM). Finite resolution in a measurement that is perturbed by Gaussian noise yields a distribution of results that strongly depends on the location of the true value relative to the resolution increment. We show that there is no simple expression relating the standard deviation of the distribution of measurement results to the associated uncertainty at a specified level of confidence. There is, however, an analytic relation between the mean value and the standard deviation of the measurement distribution. We further investigate the conflict between the GUM and ISO 14253-2 regarding the method of evaluating the standard uncertainty due to finite resolution and show that, on average, the GUM method is superior, but still approximate.     

白光干涉测量系统的测量不确定度评定

白光干涉测量系统(white-light interference system,WLIS)广泛用于微纳米表面形貌的精密测量,其测量不确定度评定是研究白光干涉测量系统计量特性的一项重要工作.基于微纳米线间隔和台阶,建立了 WLIS测量表面形貌时的测量模型,明确了测量不确定度来源;以5000 nm的线间隔和180 nm的...     

Statistical error analysis of time and polarization resolved ultrasonic measurements

The time and polarization resolved ultrasonic technique which we previously developed has been demonstrated to simultaneously provide measurements of the wave velocity in the coupling liquid, and the leaky surface wave and leaky longitudinal wave velocities in solid samples. To document the measurement precision associated with this technique, a statistical method is employed for the data fit and error analysis. With the help of statistical analysis, the simple ray model used to determine wave velocities in this technique is first confirmed by theoretical data which are predicted by the Green's function. Error analysis is then applied to the experimental data. The results show that this technique has a relative expanded uncertainty (equal to twice the standard deviation) of 0.03% for the wave velocity in water, and an uncertainty less than 0.2% and 2%, respectively, for the leaky surface and leaky longitudinal wave velocities in a crown glass sample. The uncertainty in the repeatability for leaky surface wave measurements is observed to be much less than the expanded uncertainty of a single measurement set. This methodology also has been applied to a set of steel samples. The results allow that the expanded uncertainty for leaky surface wave velocities is less than 0.07%, enabling a correlation of the measured velocities with specific sample heat treatments.     

比浊法测定土壤有效硫的探讨

对比浊法测定土壤有效硫中的前处理部分进行了改进,即采用活性碳代替H_2O_2去除有机质,活性碳用量以0.04g为最佳;对12种不同土壤采用改进的新方法测定,结果与原方法显著相关,相关系数为0.9966,相关方程为Y=3.4121+1.0531X,新方法的回收率为96.48%～101.15%,标准差为0.099～0.382,变异系数为0.547%～4.321%,与原方法相比,新方法更加快速、简便、精确、重复性和再现性均好,易于推广。     

碳纤维/树脂复合材料多钉连接钉载系数测试方法

为解决由于碳纤维/树脂复合材料多钉连接结构中钉载分配状态和测试方法不同导致的钉载系数测试分散性不明确的问题,针对应变片和钉载矢量传感器两种测试方法,提出基于不确定度理论的钉载系数相对测量不确定度的计算模型,并计算两种测试方法对碳纤维X850/树脂复合材料单剪、双剪连接结构钉载系数的相对测量不确定度。结果表明,应变片测试方法中,单剪结构钉载系数无法准确测量,双剪结构钉载系数相对测量不确定度通常超过2.8%,且随结构中螺栓数目和应变片贴片角度偏差的增加而增大;钉载矢量传感器测试方法中,单剪、双剪结构钉载系数均可测试,且针对任意螺栓数目结构,其钉载系数相对测量不确定度最大不超过1.5%。