共查询到19条相似文献,搜索用时 93 毫秒
1.
生丝纤度变异系数是生丝电子检验分级标准中的一项主要质量检验指标。为了在生丝电子检验中合理设计生丝纤度变异系数(CVeven和CV5m)分级标准,需要准确了解其分布形态。通过对6批生丝进行电子检测试验,调查电子检验中CVeven和CV5m的频数分布,利用卡方检验进行正态分布拟合检验,运用KS统计量检验方法进行混合正态分布拟合检验,并对两分布拟合度进行比较分析。结果表明:生丝纤度变异系数分布反映了生丝质量、缫丝企业的管理水平;生丝纤度变异系数(CVeven和CV5m)服从由两个正态分布组成的混合分布。 相似文献
2.
3.
棉铃虫是陕西省烤烟留种田后期主要害虫之一。幼虫分布型调查表明,它主要为波松和负二项分布,且随密度而变化,但适合于Taylor幂法则:S2=1.07523m0.9931。经推导演算,得出理论抽样公式为:n=1.07523(t/D)2·m-1.0069适合烟田棉铃虫幼虫调查的序贯抽样模型为T'0(n)=0.15n+1.96√0.1634nT0n(n)=0.15n-1.96-1.96√0.1634n最多只需抽取16株。对各种机械抽样方法比较后,认为实践中用平行线10点100株取样比较合适。 相似文献
4.
当正态线性模型中的参数取逆χ^2先验分布时,得出了回归系数和误差方差的联合后验分布和边际后验分布,特别导出了回归系数二次型的分布。利用回归系数和误差方差联合后验分布的分解形式,给出了一种抽样方案。 相似文献
5.
6.
7.
8.
9.
本文推导了按重量加权的长度变异系数与纤维束截面积分布函数之间的关系。据此设计的电路已应用于YMC-300(Ⅱ)型羊毛长度仪。 相似文献
10.
11.
研究了双液相溶剂(甲醇相 石油醚)浸取破碎棉仁的工艺特性,测定了达到浸取平衡的时间,考察了温度、甲醇相浓度等因素对游离棉酚分配系数的影响.结果表明,甲醇相中加入一定量的柠檬酸可以提高游离棉酚在甲醇相中的分配系数,而且温度越高,甲醇相浓度越大,分配系数越大.并提出了一个经验方程用以关联分配系数与浸取温度、甲醇相浓度的关系,平均相对误差为4.65%. 相似文献
12.
13.
14.
关于从属函数的系数不等式 总被引:1,自引:0,他引:1
张宇萍 《纺织高校基础科学学报》2000,13(2):128-130
讨论Schwarz函数的不等式,证明了当f(z)=∞∑n=0anz^n从属于g(z)=∞∑(n=0)bnz^n时,/a3/≤√2max(/b1/,/b2/,/b3/),并且等号是可达的。 相似文献
15.
食品安全监督抽检是保障我国食品安全监管工作的重要一环,许多地市都将食品检验量及问题发现率作为政府对食品安全工作的考核指标。随着食品监管力度的增强和品牌经销商逐步占领市场,各终端经营场所销售的食品大致相同,这就使随机开展的食品安全监督抽检重复抽检现象客观存在。本文根据我国现行食品安全监督抽检现状,尝试从不同业态,不同抽检机构,样品差异性,抽样人员主观因素等方面分析造成重复抽检的原因,就如何保证抽样的代表性、减少重复抽检问题提出:加强科学制定计划,使用抽检APP共享抽样信息、限制重复数据,分任务制定检验项目,加强过程监管丰富样品来源,引入监督机制等相关建议。以期为避免重复抽检浪费经费,提高问题发现率和制定食品安全抽样工作规范提供参考。 相似文献
16.
The paper was designed to assess the effect of the type of milk meter used by dairy farms for official milk testing to obtain individual milk samples for fat and protein determination. This study was performed in 2006 in Galicia, which is Spain's main dairy cattle region; data were collected from 2,149 Holstein cow farms enrolled for official milk recording. Findings indicate that the milk sampling system used has a substantial effect on the fat contents recorded for individual milk samples. Such variation could arise from poor functioning of the equipment, inadequate mixing of the milk portion from which the sample is obtained, or from the nonproportionality of the sample. Samples obtained from only one point in the milk line may not be representative of all the milk produced. The most significant differences are observed in the percentage of fat, whereas differences in percentage of protein are smaller. The sampling method used should, but does not always, provide a representative sample of the milk from a single milking. 相似文献
17.
18.
Magdi El Messiry 《纺织学会志》2020,111(3):416-423
AbstractThe drape is an important characteristic of textile fabrics. Several studies have been concerned with the mechanism of fabric drapability and the methods of its measurements. In this study, a new drape coefficient ‘DCM’, evaluating the shape of the fabric drape, is defined in terms of the drape projection, the shape and the number of the folds and the drape angle. The drape of fabric samples with different weft densities and weaves structures was tested. The new formula to express the drape coefficient, taking into consideration the fabric flexural rigidity, was developed. The analysis of the experimental results indicated that the modified drape coefficient is highly correlated with fabric flexure rigidity and other fabric structure properties than the other known formulas. 相似文献