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为保证测量结果的准确性,对商品试剂盒微生物法测定鸡枞菌中叶酸含量不确定度进行分析。依据CNASCL01-G003-2019要求,并按照JJF 1059.1-2012和GB/Z 22553-2010对实验结果有影响的各个分量进行评估,即对样品测定重复性、样品称量、样品检测过程三个方面引入的不确定度进行分析,并确定了各不确定度分量,得出扩展不确定度。各分量不确定度从大到小分别为样品测定重复性0.0272、移液枪自身容差0.0226、标准品纯度0.002887、温度变化0.0006、容量瓶定容0.0006、样品称量0.00001633;相对合成标准不确定度为0.0356,扩展不确定度为7.7857,测量结果为(109.35±7.7857)μg/100 g。影响微生物法测定鸡枞菌中叶酸含量的最主要不确定度分量为样品测定重复性、移液枪自身容差、标准品纯度引入的不确定度。 相似文献
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通过对火焰原子吸收分光光度法测定不锈钢中锰含量的不确定度的系统分析,阐述了测量结果不确定度主要来源于工作曲线拟合引起的不确定度、锰标准溶液及配制引入的不确定度、重复测得样品产生的不确定度,并对这些分量进行了量化计算,最后计算出合成标准不确定度和扩展不确定度。 相似文献
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根据GB 5009.87-2016《食品安全国家标准食品中磷的测定》中的分光光度法测量试样。利用测量不确定度的评价方法和步骤建立数学模型,对食品中磷含量的分光光度法的不确定度进行评估。根据实验过程中的各个分量的不确定度来源进行分析,并对所有不确定度进行合成,得出分光光度法测定食品中磷含量不确定度评定结果。结果表明:当食品中的磷含量为12.87%时,其扩展不确定度为0.3%,k=2。 相似文献
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[目的]全面评定分光光度法不正确定度来源.[方法]采用分光光度法测定水中微量铁,并对测量结果进行不确定度的评定和说明.[结果]测量结果:0.606mg/L;测量扩展不确定度:0.036mg/L(K=2).[结论]标准曲线拟合引入的不确定度分量是不确定度分量中最大的,因此降低该分量对降低该方法测量不确定度效果最明显. 相似文献
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[目的]全面估计分析不确定度的来源,得出其扩展不确定度,对测量不确定度进行评定.[方法]采用EDTA滴定法测定水质总硬度,并对测量结果的质量进行不确定度的评定和说明.[结果]测量重复性、标准溶液的配制、滴定等过程对测量有影响,是构成其结果不确定度的主要因素.计算水质总硬度的测量相对合成标准不确定度为1.52×10-3[结论]标定EDTA标准溶液浓度引入的不确定度分量是不确定度分量中最大的,因此降低该分量对降低该方法测量不确定度效果最明显. 相似文献
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按照GB/T 23383-2009利用反相高效液相色谱法对肉制品中双乙酸钠含量进行分析,建立数学模型,对测量结果的不确定度来源如标准物质、校准工作曲线、样品处理、回收率等各不确定度分量进行分析评定及量化。按数学模型计算得肉制品中双乙酸钠含量为0.460g/kg时,本方法的标准不确定度为0.022g/kg,扩展不确定度为0.044g/kg,最终结果的不确定度主要由样品溶液中双乙酸钠含量和样品处理过程产生。 相似文献
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Festus B. Odukudu Joseph G. Ayenimo Abolanle S. Adekunle Adeyinka M. Yusuff Bhekie B. Mamba 《International Journal of Consumer Studies》2014,38(1):25-34
The determination of heavy metals in consumer products is crucial for the safety appraisal and sources classification of human and environmental exposures. These products contain various undisclosed chemical constituents with no or little known health safety information. The public is generally unaware of these types of everyday exposure from chemical constituents of consumer products and their health consequences. In this study, we recorded a body of proof demonstrating potential harm of consumer goods, by determining concentrations of total cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn), iron (Fe), lead (Pb) and nikel (Ni contents in a variety of personal care products (n = 82) commonly used in Nigeria, using flame atomic absorption spectrometer after dry and wet digestion methods. The results of the analysis indicated that the range of Cd was 0.035 ± 0.023–0.467 ± 0.167 ppm, Cr 0.015 ± 0.009–0.435 ± 0.232 ppm, Cu 0.230 ± 0.08–0.603 ± 0.025 ppm, Zn 0.003 ± 0.005–0.743 ± 0.066 ppm, Fe 0.233 ± 0.219–1.401 ± 1.878 ppm, Pb 0.02 ± 0.007–0.2050.129 ppm and Ni 0.035 ± 0.015–0.093 ± 0.06 ppm. The values of Cd and Cr are a cause for alarm because the elements are not allowed in any amount in cosmetics. Despite the fact that zinc is essential in the body, the values obtained in this study deserves safety concerns due to cumulative effect, arising from incessant exposure. 相似文献
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[目的]通过对影响测定结果的不确定度因素的分析和量化,评价石墨炉原子吸收光谱法测定水样中铬的不确定度。[方法]调节仪器最佳测定条件,测定铬标准工作溶液系列并依据工作软件自动建立工作曲线和数学模型;连续测量10次水样,根据标准曲线获得未知样品铬浓度;分析石墨炉原子吸收分光光度法测定水样中铬的误差性质和来源,确定不确定度的主要因素,计算水样中铬的测量不确定度。[结果]扩展不确定度U95=0.016mg/L(Veff=20)。[结论]根据分析仪器的测定数据输出方式建立数学模型,进行不确定度评定,方法直观简明,与实际工作相符合。 相似文献
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AbstractIn present-day Japan, more firms are beginning to apply postponed product differentiation in favor of providing mass-customized products. Mass customization can lead to competitive advantages in satisfying consumers’ individual needs. We propose a causal model to describe why and how Japanese distributors decide to postpone product differentiation and supply mass-customized products. The model was empirically tested by structural equation modeling with a dataset from Japanese automobile dealers, who have employed highly advanced mass customization systems and are world leaders in this practice. The results show that two environmental factors, uncertainty and innovation, affect firms’ expectations of their customers’ intentions to purchase mass-customized products and, in turn, firms’ decisions regarding postponing product differentiation in favor of mass customization. Mass customization has a high potential for growth in the future due to increasing levels of uncertainty and evolving forms of innovation. 相似文献
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In the online retail market, consumers' uncertainty about products caused by the physical separation between consumers and products has long been an obstacle. In recent years, online retailers have begun to display their products by using augmented reality technology. However, whether and how the features of augmented reality influence consumers’ product uncertainty remains unclear. In this study, we explore the effects of augmented reality features on product uncertainty reduction and product attitude. The results show that augmented reality can reduce product quality and fit uncertainty by increasing perceived informativeness, sense of presence, and mental imagery. The relationship between augmented reality features and product uncertainty reduction are moderated by product involvement, need for sensory richness and self-brand connection. Ultimately, the reduction of product uncertainty leads to positive product attitude. 相似文献
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为评估化妆品中镉和汞潜在健康风险,课题组从多种渠道随机选取化妆品样品作为本次调查研究对象,通过固体进样汞镉测定仪测定了半永久纹绣产品、面膜和面霜三大类别化妆品中重金属的含量,针对通过皮肤接触途径的暴露特性,采用美国环境保护局(USEPA)推荐的健康风险模型,对重金属汞、镉通过皮肤接触途径引起的健康风险进行初步评价。结果发现,纹绣、面膜和面霜三类化妆品的风险值与USEPA推荐的风险值比较风险甚微,但值得注意的是,单独将两个超标样品进行评估,数值分别为1.0×10-6/年和1.7×10-6/年,则表示存在一定风险。 相似文献