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基于近红外的掺糖红茶快速无损检测方法
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作者 罗正飞 龚正礼 +2 位作者 杨坚 杨崇山 董春旺 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2023年第8期2649-2656,共8页
为实现成品红茶中外源蔗糖含量的快速有效检测,将凤庆大叶种红茶作为研究样本,采用近红外光谱技术,构建了成品红茶中外源蔗糖含量的定量预测模型。首先,制作不同外源蔗糖含量(0、250、500和750 g)成品红茶样品并采集其近红外光谱数据。... 为实现成品红茶中外源蔗糖含量的快速有效检测,将凤庆大叶种红茶作为研究样本,采用近红外光谱技术,构建了成品红茶中外源蔗糖含量的定量预测模型。首先,制作不同外源蔗糖含量(0、250、500和750 g)成品红茶样品并采集其近红外光谱数据。为提高模型预测精度,选取标准正态变换(SNV)、多元散射校正(MSC)、平滑(Smooth)和中心化(Center)4种不同的预处理方法降噪处理后建立偏最小二乘回归(PLSR)模型,根据模型效果,优选出最佳的SNV预处理方法,其校正集相关系数(R_(c))为0.907,预测集相关系数(R_(p))为0.826,相对标准偏差(RPD)为1.75。为减少光谱中冗余信息对模型运算速度的影响,利用竞争性自适应加权算法(CARS)、混合蛙跳算法(SFLA)、迭代空间收缩算法结合迭代保留信息变量算法(VCPA-IRIV)和变量迭代空间收缩算法(VISSA)等方法从SNV预处理后的光谱中提取对蔗糖敏感的特征波长,利用主成分分析(PCA)将全光谱和所筛选的特征波长降维处理后,分别建立线性PLSR和非线性的支持向量回归(SVR)、随机森林(RF)定量预测模型。结果表明,经过SNV预处理后,非线性的SVR和RF模型性能优于线性的PLSR模型,其中VCPA-IRIV-SVR为最优模型,其R_(c)值为0.950,R_(p)值为0.924,RPD值为2.51。研究表明近红外光谱技术对于红茶加工过程中掺杂蔗糖含量的定量预测是可行的,为实现红茶安全质量的无损检测提供了支撑。 展开更多
关键词 红茶 掺糖 近红外光谱 无损检测
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Modelling and Simulation of Scraper Reliability for Maintenance
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作者 HUANG Liang-pei LU Zhong-hai gong zheng-li 《International Journal of Plant Engineering and Management》 2011年第3期139-145,共7页
A scraper conveyor is a kind of heavy machinery which can continuously transport goods and widely used in mines,ports and store enterprises.Since scraper failure rate directly affects production costs and production c... A scraper conveyor is a kind of heavy machinery which can continuously transport goods and widely used in mines,ports and store enterprises.Since scraper failure rate directly affects production costs and production capacity,the evaluation and the prediction of scraper conveyor reliability are important for these enterprises.In this paper,the reliabilities of different parts are classified and discussed according to their structural characteristics and different failure factors.Based on the component's time-to-failure density function,the reliability model of scraper chain is constructed to track the age distribution of part population and the reliability change of the scraper chain.Based on the stress-strength interference model,considering the decrease of strength due to fatigue failure,the dynamic reliability model of such component as gear,axis is developed to observe the change of the part reliability with the service time of scraper.Finally,system reliability model of the scraper is established for the maintenance to simulate and calculate the scraper reliability. 展开更多
关键词 可靠性建模 刮板输送机 可靠性模型 仿真 维护 存储企业 可靠性评价 连续运输
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