棉花长度试验方法 手扯尺量法不确定度的评价方法

介绍了测量不确定度评估的一般方法和步骤,通过棉花手扯长度测量不确定度的评定应用实例阐述了测量不确定度的评定方法。     

菌落总数测定结果不确定度的评定

目的对质控样中菌落总数测定结果进行不确定度评定。方法菌落总数测定依据GB4789.2-2016《食品安全国家标准食品微生物学检验菌落总数测定》进行测定和结果判断,再根据JJF 1059.1-2012《测量不确定度评定与表示》的规定,对测定过程中引入的不确定度分量进行评定,然后采用合成的方法来计算和评定菌落总数的不确定度。结果扩展不确定度为0.08,结果对数值取值区间为(3.85±0.08),取反对数取值区间则为(5900, 8500)。结论本方法可有效评定菌落总数的不确定度。     

糕点中菌落总数测量结果的不确定度的评定

目的对糕点中菌落总数的测量结果进行不确定度评定。方法依据GB 4789.2-2016 《食品安全国家标准食品微生物学检验菌落总数测定》对糕点中菌落总数进行测定,建立数学模型,分析检验结果的影响因素,对不确定度因素的影响进行评价。结果通置信水平为95%,包含因子k=2,得10批样品的扩展不确定度分别为:0.2156、0.1194、0.1267、0.1293、0.1298、0.1163、0.1293、0.1155、0.1181、0.1243。结论糕点菌落总数检验中重复性检验和培养基的菌落生长率对不确定度影响最大,需要在检测过程中进行注意。     

山羊绒回潮率测定结果的不确定度评定

检测结果不确定度的评定，通常是通过对各不确定度分量的分析、评定与合成予以实现。山羊绒回潮率测定结果的不确定度取决于实验用原试样及其烘干后试样质量称量的不确定度和回潮率测定结果的非重复性不确定度。其回潮率测定结果的非重复性不确定度属A类评定；而原试样及烘干后试样质量称量的不确定度，属B类评定、均匀分布。在其评定的基础上，求出其合成标准的不确定度，进而取包含因子k=2而求得扩展不确定度。     

纺织品中有机锡化合物测定不确定度评估

按照GB/T 20385-2006标准测定纺织品中有机锡化合物的含量,以二氯二丁基锡为例对该方法整个过程中产生的测量不确定度进行评估.通过对不确定度来源的分析、量化,合成了不确定度.结果表明,按本试验方法,纺织品中有机锡化合物测定过程中随机效应是最大的影响因素;被测样品中有机锡的含量在1.2～1.6 mg/kg,其扩展不确定度为0.2 mg/kg.     

液相色谱测定茶油中维生素E结果的不确定度评定

分析茶油中维生素E的测量不确定度与影响不确定度的因素.方法依据JJF 1059-1999<测量不确定度评定与表达>原理和方法.计算茶油中维生素E测定值相对扩展标准不确定度.结果表明HPLC测定茶油中维生素E为669.25μg/g,相对扩展不确定度为10.56%.其不确定度分量主要包括:①标准溶液的相对扩展不确定度;②称样的相对不确定度;③定容的相对不确定度;④重复测定的相对不确定度;⑤标准曲线线性拟和的相对不确定度;⑥回收率的相对不确定度.全面反映检测全过程是不确定度分析的关键,通过评定得出回收率和线性拟和是本实验的不确定度最大来源,应最值得重视.     

挂面酸度测定结果的不确定度评定

对测定挂面酸度的整个过程进行不确定度的来源分析与量化,找出引起不确定度的主要因素,评定确认影响测定结果的主要原因是滴定管、样品的重复性测定,其次是量筒量取浸泡试样的蒸馏水体积、氢氧化钾标准溶液、吸取滤液的分度吸量管。本次挂面酸度测定的扩展不确定度为0.127mL/10g。     

锅巴中水分测量结果的不确定度评定

目的 对锅巴中水分测量结果进行不确定度评定。方法 依据GB 5009.3-2016《食品安全国家标准 食品中水分的测定》第一法直接干燥法对锅巴中的水分进行测定,建立数学模型,分析检验结果的影响因素。结果 通过分析3种不确定的影响因子,得出不确定度分别为：3.30×10-3、2.75×10-4、2.92×10-3。结论 通过对各不确定度分量进行计算和分析表明, 锅巴水分检验中重复性测量对不确定度影响最大,天平称量的影响最小。     

白砂糖中二氧化硫测定结果的不确定度分析

白砂糖中二氧化硫含量是反映白砂糖质量的一个重要指标。根据中国实验室国家认可委员会的《化学分析中不确定度的评估指南》,通过对GB/T5009.34-l996盐酸副玫瑰苯胺法测定食品中亚硫酸盐含量的测定过程进行研究,系统分析了该法测量白砂糖中二氧化硫结果的不确定度来源并对其进行评定,对各不确定度分量进行了量化,提出了该法的合成不确定度及检测过程中的注意环节。     

光电检测技术在大容量棉纤维长度测试中的应用

从光电检测技术的原理出发,介绍了应用在大容量棉纤维长度测试系统中的长度测试模块的原理、组成及各部分的设计,利用光电技术设计的长度测试模块把基于棉纤维的长度参量变化转化为对光传输路径上光强度的调制,通过光电接收器将这个光调制信号,即棉纤维的长度变化信号检测出来。样机实验表明,这一方法测试结果与传统测试结果高度相关,相关系数在0.93以上,测试速度快,系统的线性度、灵敏度、信噪比等都能满足棉纤维性能测试仪的设计要求,达到了预期的目的。     

Impacts of yarn twist and staple length on UV protection of plain-knitted cotton fabrics

Yarn construction is an important attribute in knitting and end use performance of knitwear. Holistically, yarn construction affects fabric thickness and weight, and thereby influences ultraviolet (UV) protection of fabrics. Although impact of yarn construction on UV protection of fabrics is apparent, there appears to be limited research on it. This paper studied the UV protection of plain-knitted fabrics made of three types of ring-spun cotton yarns varying in yarn twist level and staple length. The results show that these yarn properties affect UV protection of fabrics differently before and after laundering. The modified low-twisted yarn possesses a bulky feature which creates a porous fabric structure for more ultraviolet radiation (UVR) transmission. The extra-long staple yarn offers uniform fabric appearance for higher UVR reflection. However, the regularity of yarn also restricts the fabric shrinkage in laundering and thus improvement in UV protection by shrinkage is not as obvious as that provided by the conventional short-staple yarn.     

快速鉴别等外棉、废棉与回收纤维的方法研究

通过对选用棉花长度指标的检测方法的研究,为入境等外棉、废棉与回收纤维鉴别研究提供了快速高效可行的方法,并算出手扯长度与HVI上半部平均长度之间关系的回归方程式。所讨论的利用长度检测方法建立快速鉴别方法的设想能有力配合环保、海关、商检的监管与商业的验收。     

Application of finite mixture model in cotton fiber length probability distribution

Based on the characteristic of histograms for fiber length, a finite mixture model has been applied in this paper to characterize cotton fiber length probability distribution, which made it possible to describe the entire fiber length distribution with a parametric continuous function. With the analysis of previous researches, a mixture of Weibull distributions was chosen to generate the parametric probability density function. In this paper, five cotton fiber samples were collected from different spinning processes: bale, card mat, carded sliver, combed sliver, and finished sliver. The fiber length frequency histograms by weight, the histograms by number and some length measures were tested by USTER AFIS Pro. Two-component and Three-component mixture distributions were adopted to fit these histograms, and some length measures were calculated. Then, comparisons have been made between the calculated values of fiber length measures and the tested ones. The results showed that both the finite mixture models based on different component Weibull distributions could fit the cotton fiber length frequency histograms very well, which would be beneficial to pursue the process-related factors in cotton mills for end products.     

混合Weibull分布在棉纤维长度分布表征上的应用

利用含参数的概率密度函数来表征棉纤维的长度分布,不仅有利于纤维长度指标的计算,而且能够全面度量纤维的长度分布状态。本文基于USTER 的AFIS单纤维测试仪测得的纤维长度分布直方图,依据现有的混合Weibull分布模型,选用两组分与三组分的混合分布对其进行了拟合,并计算了相应的长度指标。结果表明：利用Weibull分布构建的混合分布模型能很好地拟合棉纤维的重量及根数加权长度分布。此外,通过指标计算值与实测值的对比,一般情况下二组分混合模型优于三组分模型。     

天丝/牛奶蛋白纤维/长绒棉混纺纱的产品开发

通过对天丝、牛奶蛋白纤维与长绒棉的品质特性分析,制定了13.8tex混纺针织用纱的生产工艺,并着重强调了提高产品质量的技术措施.     

The components of staple tenacity and the determinants of length after carding

A theoretical model for the tensile strength of staples of wool was used to propose variables that could be measured on thirty six fleece samples from Romney sheep genetically selected on the basis of wool staple tenacity. Other variables that have been noted elsewhere in the literature were also measured. Nearly 75% of the variation in staple tenacity was described by average and minimum cross-sectional area of the fibres, and the relaxed length of the fibres held between the jaws of the instrument used to break the staple. The addition of staple length and variation in total length of the fibres in the staple improved this to almost 84%. The ultimate goal of the genetic selection was to increase the average length of fibres following carding (Hauteur and Barbe), which were also measured on the fleece samples, and the fibre, staple and sample measurements used in stepwise regression to reveal the determinants of length after carding. Variation in Hauteur was dependent on the total energy required to break the staple and the proportion of new tips present in the post-break region of the staple, yet as little as 52% of the variation was accounted for. Average cross-sectional area accounted for a further 3% of the variation in Hauteur but this was not statistically significant. Barbe was dependent on staple tenacity, which accounted for 48% of the variation. In hindsight, staple tenacity may not be an appropriate measure to genetically select sheep in order to improve fibre length after carding given the variables that affect these traits.     

漂白棉短纤维的梳理

描述了拥有全新设计的针布和盖板的固定盖板系统Card Perfector的结构、特性和应用.Card Perfector系统包括针布优化的计算机辅助装置、针布、盖板、吸风装置、固定部件及其他必要的零部件.采用这个系统,棉结数量可大幅度减少,短片断不匀也可较好地改善.     

中段切断称量法测棉纤维细度之误差浅析

棉纤维细度是影响棉纱线性质的重要因素。中段切断称量法测试棉纤维细度的方法普遍存在测得数值偏大的现象。文章对中段切断称量法进行了分析研究,归纳出因人为因素和客观因素造成细度结果偏大,建议采用数值修正和多种测试方法进行交叉校验,同时,要提高操作人员的技术水平,保证测试结果的准确、可信。     

Generation of cotton fiber length probability density function with length measures

This report describes an investigation into the generation of fiber length distributional function using a limited number of length measurements. Based on the experimental data, the correlation between fiber length statistics (the calculated mean value and variance) and length measures (tested short fiber content, span lengths, etc.) was identified by employing the stepwise regression analysis, and this was necessary to describe the location and dispersion of the fiber length distribution. Then, a finite mixture model was adopted to generate the probability density function of fiber length. This paper concludes with a presentation of the approach to determine the probability density function of cotton fiber length. It is shown that the calculated short fiber contents and upper‐quartile length from the probability density function fit the experimental values well.