共查询到19条相似文献，搜索用时 93 毫秒
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对脉冲惰性气体保护红外吸收法测定钛合金中氧含量的检测结果进行了不确定度评定,采用A类不确定度对称量过程、仪器示值和标准物质的不确定度进行评定,采用B类不确定度对连续测量和建立工作曲线引入的不确定度进行评定,对样品检测过程的不确定度分量进行分析,重点讨论了称量不确定度和线性拟合引入的不确定度进行量化评定,计算了钛合金样品中氧含量的标准不确定度和扩展不确定度,在本试验中,线性拟合过程和标准物质不确定度分量是不确定度的主要来源,对此提出了减小测量不确定度的方法. 相似文献
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给出了大学物理实验中量的A类分量不确定度、B类分量不确定度、合成标准不确定度的表示方法,并用两个实例讨论了标准不确定度的评定问题。 相似文献
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盐酸标准溶液标定的不确定度评定 总被引：1，自引：0，他引：1
曾勤 《黎明职业大学学报》2006,(4):32-35
对盐酸标准溶液标定的不确定度进行了评定。分析了盐酸标准溶液标定的不确定度的主要来源,通过数学模型对各不确定度分量进行了评定,结果表明,盐酸标准溶液的浓度为0.1002±0.00031mol/L(k=2) 相似文献
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标准溶液稀释不确定度评定 总被引：2，自引：0，他引：2
依据测量不确定度评定与表示的理论,以砷标准溶液为例,对标准溶液稀释的不确定度进行了评定。通过识别稀释过程中的不确定度来源,分析了各个分量的产生,计算了合成标准不确定度。结果表明,移液器的不确定度是影响标准溶液稀释最主要的因素。 相似文献
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评定了按照GB/T601-2002方法配制和标定硫代硫酸钠标准溶液浓度的不确定度。主要从实验方法、建立数学模型、确定不确定度的来源、计算相对不确定度分量、合成不确定度、扩展不确定度等入手,介绍了硫代硫酸钠标准溶液的不确定度评定过程。 相似文献
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唐重任 《安徽科技学院学报》2008,22(5)
本文以二苯碳酰二肼分光光度法测定水中六价铬为例,阐述校准曲线法不确定度评定与表示的理论,分析了不确定度的主要来源,评定了不确定度分量及总不确定度,为使用校准曲线法这一类型的不确定度分析和计算提供参考. 相似文献
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该文在讨论测量标准不确定度的A类与B类评定过程中,叙述了B类与A类不确定度的区别,同时把实验标准偏差和测量结果的取值要求结合起来,以及把B类不确定度分量的概率分布具体列出来,使得A类和B类不确定度的评定更合理. 相似文献
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王继军 《九江职业技术学院学报》2006,(3):22-24
详细论述了电能表检验装置测量不确定度的评定方法；介绍了怎样充分且合理地选择和确定测量不确定度的分量并将它们归为A类或B类标准不确定度以及怎样按国际惯例汇总和报告测量不确定度的结果。 相似文献
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该文在讨论测量标准不确定度的A类与B类评定过程中，叙述了B类与A类不确定度的区别，同时把实验标准偏差和测量结果的取值要求结合起来，以及把B类不确定度分量的概率分布具体列出来．使得A类和B类不确定度的评定更合理． 相似文献
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采用气质联用法分析测量审核样品中多溴二苯醚含量的不确定度,通过建立数学模型,找出影响测量不确定度的因素,并对各不确定度的分量进行评估。由计算各变量的不确定度,计算合成不确定度,最终给出测定结果的扩展不确定度和含量范围。建立的不确定度评估方法可用于气质联用法测定多溴二苯醚含量的不确定度评定。 相似文献
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目的:以最小二乘法直线度评定食品中砷测定过程中存在的不确定度,并找出影响不确定度的因素较大的环节。方法:根据GB/T 5009.11-2003《食品中总砷及无机砷的测定》的方法,应用最小二乘法拟合直线,进行不确定度评估,并计算出合成不确定度。结果:各分量中工作曲线变动性、移液管、样品定容过程及测量重复性引入的不确定度贡献较大,相对扩展不确定度为U=2.5%(k=2)。结论:以最小二乘法直线度评定食品中砷的不确定度,提高了评定的可信度,通过实验各环节的分析,要求操作过程必须细心、准确、规范,尽量减少不确定度。 相似文献
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讨论了磁铁矿中磁性铁含量测量结果不确定度的多种影响因素,分析了测量结果不确定度分量的主要来源。并对它们进行了计算。通过比较得出,在测量磁铁矿中磁性铁含量的过程中,重复磁选磁性铁过程是测量结果不确定度影响最大的因素。其次是重铬酸钾标准溶液滴定消耗体积的不确定度所造成的测量结果不确定度的影响。通过测量国家一级标准物质GBW07272得出,当测得磁性铁含量为46．91％时,其扩展不确定度U=0．52％（k=2）。 相似文献
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ObjectivesIn light of the current U.S. family separation crisis, there is growing attention to Childhood Traumatic Separation, defined here as a significant traumatic stress reaction to a familial separation that the child experiences as traumatic. When living in a family setting, Childhood Traumatic Separation may interfere with the child's relationships with the current caregiver(s). Effective treatments for Childhood Traumatic Grief can be modified to address Childhood Traumatic Separation. This article describes current applications of Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) for Childhood Traumatic Separation.MethodsUsing two composite clinical cases, TF-CBT applications for Childhood Traumatic Separation are described. These include: (1) implementing the safety component first; (2) tailoring coping skills to address the uncertainty of Childhood Traumatic Separation; (3) integrating past traumas into trauma narration and processing of the traumatic familial separation; (4) providing Childhood Traumatic Separation-focused components to address challenges of committing to new relationships while retaining connections to the separated parent; and (5) addressing role changes.ResultsThese modifications have been implemented for many youth with Childhood Traumatic Separation and have anecdotally resulted in positive outcomes. Research is needed to document their effectiveness.ConclusionsThe above practical strategies can be incorporated into TF-CBT to effectively treat children with Traumatic Separation.Practical implicationsPractical strategies include starting with safety strategies; tailoring skills components to address the ongoing uncertainty of traumatic separation; integrating past traumas into trauma narration and processing of traumatic separation; providing traumatic separation-focused components to balance the challenges of committing to new relationships with retaining connections to the separation parent; and addressing role changes. Through these strategies therapists can successfully apply TF-CBT for Childhood Traumatic Separation. 相似文献
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In the face of accumulating research and logic, the use of a discrepancy between intelligence and reading achievement test scores is becoming increasingly untenable as a marker of reading disabilities. However, it is not clear what criteria might replace the discrepancy requirement. We surveyed 218 members of journal editorial boards to solicit their opinions on current and proposed definitional components and exclusion criteria. Three components were selected by over two‐thirds of the respondents: reading achievement, phonemic awareness, and treatment validity. However, only 30 percent believed IQ‐reading achievement discrepancy should be a marker. More than 75 percent of the respondents believed exclusion criteria should remain part of the definition. Mental retardation was the most frequently selected exclusion criterion despite rejection of intelligence test scores as a definitional component. Although the findings reflect uncertainty among experts on what elements should comprise a definition, they do signal a willingness to consider new approaches to the conceptually difficult task of defining reading disabilities. 相似文献
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Linda Schenk Karim M. Hamza Margareta Enghag Iann Lundegård Leena Arvanitis Karin Haglund 《International Journal of Science Education》2019,41(9):1271-1286
The present paper takes its point of departure in risk being a relevant content for science education, and that there are many different approaches to how to incorporate it. By reviewing the academic literature on the use and definitions of risk from fields such as engineering, linguistics and philosophy, we identified key elements of the risk concept relevant for science education. Risk is a phenomenon of the future that may be conveyed by our activity, it is something that may or may not take place. Hence, at the core of risk we find uncertainty and consequence. Furthermore, the elements of probability and severity are relevant modifiers of the consequence, as well as both subject to uncertainty. Additionally, in framing, understanding and decision-making on risk, as individuals or society, we need to acknowledge that risk has both objective and subjective components, lying in the interface between knowledge and values. In this paper, we describe how these key elements were derived from the literature and derive a schematic model of the risk concept for the purpose of science education. We further discuss how this model may assist in planning, execution and evaluation of teaching activities explicitly or implicitly involving risk issues. 相似文献
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Jennifer L. Bevan Kristen A. Stetzenbach Eric Batson Kulamo Bullo 《Communication quarterly》2013,61(3):367-381
Guided by the theoretical concept of uncertainty, the present study was an exploratory investigation of general partner and relational uncertainty within sibling relationships. Undergraduate and graduate student participants responded to a written survey utilizing scales measuring general partner uncertainty, relational uncertainty, extent of topic avoidance, and various relational and demographic items. Results revealed that siblings experience significantly more partner uncertainty than relational uncertainty, although both uncertainty types were experienced at low to moderate levels. Further, differing levels of partner and relational uncertainty were associated with frequency of sibling contact, but not with sibling dyadic gender composition. Finally, both general partner and relational uncertainty were significant predictors of levels of general topic avoidance, although neither uncertainty type predicted romantic/sexual relationship topic avoidance levels. Theoretical implications for uncertainty management are discussed in light of the unique sibling relationship. 相似文献
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Zoë E. Buck Hee-Sun Lee Joanna Flores 《International Journal of Science Education》2013,35(14):2391-2420
We investigated how students articulate uncertainty when they are engaged in structured scientific argumentation tasks where they generate, examine, and interpret data to determine the existence of exoplanets. In this study, 302 high school students completed 4 structured scientific arguments that followed a series of computer-model-based curriculum module activities simulating the radial velocity and/or the transit method. Structured scientific argumentation tasks involved claim, explanation, uncertainty rating, and uncertainty rationale. We explored (1) how students are articulating uncertainty within the various elements of the task and (2) the relationship between the way the task is presented and the way students are articulating uncertainty. We found that (1) while the majority of students did not express uncertainty in either explanation or uncertainty rationale, students who did express uncertainty in their explanations did so scientifically without being prompted explicitly, (2) students’ uncertainty ratings and rationales revealed a mix of their personal confidence and uncertainty related to science, and (3) if a task presented noisy data, students were less likely to express uncertainty in their explanations. 相似文献