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Determination of 7 Indictor Polychlorinated Biphenyls (PCBs) Residues in Porphyra by Ultrasonic Extraction and Gas Chromatography (GC)
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作者 Liangliang Tian Feng Han +6 位作者 Youqiong Cai Cong Kong Yongfu Shi Yuan Wang guangxin yang Qianyun Zhan Dongmei Huang 《Journal of Agricultural Chemistry and Environment》 2016年第1期1-5,共5页
A method was developed for determination of 7 indictors the polychlorinated biphenyls (PCBs) residues in porphyra by gas chromatography (GC) with electron capture detector (ECD). The PCBs were extracted with hexane/me... A method was developed for determination of 7 indictors the polychlorinated biphenyls (PCBs) residues in porphyra by gas chromatography (GC) with electron capture detector (ECD). The PCBs were extracted with hexane/methylene chloride (1:1, v/v) by ultrasonic extraction and the samples were cleaned up by concentrated sulfuric acid and Alumina-N solid phase extraction cartridge. The analytes were quantified by an internal standard method. Under optimal experimental conditions, good linearity was observed in the range of 5 - 200 ng/mL and the correlation coefficients were 0.9994 - 0.9998. The limit of quantitation (LOQ) for target analytes ranged from 6.0 to 10.0 μg/kg. At the spiked levels of 10, 50, 100 μg/kg, the average recoveries ranged from 90.9% to 102% with the relative standard deviations 2.12% - 6.32%. The result showed that the proposed method was rapid, and could be used for the determination of the PCBs in porphyra. 展开更多
关键词 Polychlorinated Biphenyls (PCBs) PORPHYRA Ultrasonic Extraction Gas Chromatography (GC)
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低温胁迫下冬小麦叶绿素含量高光谱估测 被引量:5
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作者 张雪茹 冯美臣 +4 位作者 李广信 杨武德 王超 郭小丽 史超超 《山西农业科学》 2017年第4期526-529,共4页
近年来,拔节期冻害已成为影响北方冬麦区主要的农业气象灾害。为实现低温胁迫下冬小麦叶绿素含量的精确诊断,利用多元统计分析方法(偏最小二乘法和逐步多元线性回归)提取低温胁迫下冬小麦叶绿素含量特征波段,并构建其估测模型。结果表明... 近年来,拔节期冻害已成为影响北方冬麦区主要的农业气象灾害。为实现低温胁迫下冬小麦叶绿素含量的精确诊断,利用多元统计分析方法(偏最小二乘法和逐步多元线性回归)提取低温胁迫下冬小麦叶绿素含量特征波段,并构建其估测模型。结果表明,经B-coefficient和VIP证实,结合SMLR提取叶绿素含量监测的光谱特征波段为401,681,727 nm,预测模型的R^2,RMSE,RE分别为0.751,0.622,0.128,并且验证模型R^2也达到了0.707,模型精度较高,具有一定的普适性。利用PLS-SMLR提取特征波段、建模的方法是可行的,可为低温胁迫下冬小麦叶绿素含量估测提供一定的理论依据。 展开更多
关键词 冬小麦 叶绿素含量 多元统计分析 低温胁迫 模型
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神经肌肉刺激仪输出电流有效值的示值误差测量不确定度评定 被引量:1
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作者 王慧娟 徐阳 +1 位作者 董广新 杨祥睿 《计量与测试技术》 2017年第3期90-91,共2页
依据JJF 1059-2012《测量不确定度评定与表示》评定了神经肌肉刺激仪输出电流有效值测量结果的不确定度。建立了测量模型,分析了各不确定度分量,并计算了合成不确定度和测量结果的扩展不确定度。
关键词 神经肌肉刺激仪 输出电流有效值 不确定度
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