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地震动相位差谱的物理意义及拟合方法 被引量:2
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作者 韩旭 彭凌云 +2 位作者 王志涛 苏经宇 王丽华 《北京工业大学学报》 CAS CSCD 北大核心 2019年第12期1232-1242,共11页
为了保证人工地震波具备强度非平稳特征和频率非平稳特征,需要通过拟合方法生成频率分布特征符合要求的人工峰点到时.天然地震波的峰点到时频率分布特征普遍存在"尾部突起"现象,因此提出利用正态分布拟合调整后的峰点到时频... 为了保证人工地震波具备强度非平稳特征和频率非平稳特征,需要通过拟合方法生成频率分布特征符合要求的人工峰点到时.天然地震波的峰点到时频率分布特征普遍存在"尾部突起"现象,因此提出利用正态分布拟合调整后的峰点到时频率分布特征的方法,并根据天然地震波的峰点到时频率分布峰值优化正态分布标准差.选取符合不同条件的640条天然地震波为研究对象,分别利用正态分布、对数正态分布、伽马分布对峰点到时频率分布特征进行拟合研究,发现利用正态分布拟合方法生成的人工峰点到时频率分布特征最符合天然地震波的峰点到时频率分布特征. 展开更多
关键词 相位差谱 峰点到时 正态拟合方法 优化标准差
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Optimization of Chromatographic Conditions for Detecting Ellagic Acid in Pomegranate Peels Using HPLC Method 被引量:3
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作者 夏小龙 彭蓉 +3 位作者 李树垠 李端阳 干霞 白琦 《Agricultural Science & Technology》 CAS 2012年第11期2400-2403,共4页
[Objective] This study aimed to optimize the chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method. [Method] By using 0.2 mg/ml ellagic acid standard solution, on the basis of si... [Objective] This study aimed to optimize the chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method. [Method] By using 0.2 mg/ml ellagic acid standard solution, on the basis of single-factor experiment and orthogonal experiment, chromatographic conditions (mobile phase ratio, flow rate, col- umn temperature) for detecting ellagic acid using HPLC were optimized. Based on the optimal chromatographic conditions, the ellagic acid content in experimental pomegranate peels was determined. [Resull] The optimal chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method are: 1.2% phos- phoric acid:acetonitrile=85:15, column temperature of 35 ℃, and flow rate of 1.0 ml/min. The linear regression equation of ellagic acid is: y=2.9e+0.6x+4.4e+5 (FF=9 999). Ac- cording to the standard addition recovery test, the average recovery rate of ellagic acid is 98.20%, and RSD is 0.60%. Under above optimized chromatographic condi- tions, ellagic acid can be well separated from other interfering components in pomegranate peels, with shorter peak time and ideal effect, which is convenient for the detection in production practices. [Conclusion] This study laid the foundation for detecting ellagic acid in pomegranate peels using HPLC method. 展开更多
关键词 Pomegranate peel Etlagic acid DETECTION HPLC
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Optimization of Sample Pretreatment for Determination of Polycyclic Aromatic Hydrocarbons in Estuarine Sediments by Gas Chromatography 被引量:1
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作者 WANG Yan LI Xianguo +2 位作者 PENG Xuewei TANG Xuli DENG Xiaoyan 《Journal of Ocean University of China》 SCIE CAS 2012年第2期159-164,共6页
This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction... This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification. 展开更多
关键词 ultrasonic extraction thin layer chromatography estuarine sediment PAHS
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