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为了使植物油中脂溶性维生素E异构体得到更好的分离，建立一种超高效合相色谱（UPC2）快速分离和测定植物油中维生素A和维生素E的方法。样品经异丙醇溶解，过0.22 μm有机相滤膜后直接进样分析。分析条件为HSS C18 SB色谱柱（3.0 mm×100 mm,1.8 μm），CO2和0.2%甲酸甲醇溶液为流动相，梯度洗脱，流速1.0 mL/min，柱温50 ℃，检测波长290 nm。结果表明：维生素A和维生素E在测定范围内呈现良好的线性关系，相关系数均在0.999 5及以上，样品回收率为82.00%～106.82%，RSD在0.94%～3.57%之间，日内精密度与日间精密度的RSD分别为1.94%～3.51%与3.74%～5.13%，并采用已建立的方法对26份植物油样品中的维生素A和维生素E含量进行测定，表明植物油中维生素E含量最高，其中以α-生育酚和γ-生育酚为主，β-生育酚含量较低。该方法简单高效、灵敏度高、重复性好，可用于植物油中脂溶性维生素A和维生素E的分离检测。 In order to better separate the fat-soluble vitamin E isomers in vegetable oils, a method for rapid separation and determination of vitamin A and vitamin E in vegetable oil by ultra high performance convergence chromatography was established. The sample was dissolved in isopropanol and passed through a 0.22 μm organic phase filter membrane, and then directly injected for analysis. The analysis conditions were as follows: HSS C18 SB chromatographic column (3.0 mm×100 mm, 1.8 μm), with CO2 and 0.2% formic acid methanol solution as mobile phase, gradient elution, flow rate 1.0 mL/min, column temperature 50 ℃, detection wavelength 290 nm. The results showed that vitamin A and vitamin E showed a good linear relationships in the determination range, the correlation coefficients were not less than 0.999 5, the sample recovery was 82.00%-106.82%, the RSD was 0.94%-3.57%, and the RSD of intraday precision and daytime precision were 1.94%-3.51% and 3.74%-5.13%, respectively. The contents of vitamin A and vitamin E in 26 vegetable oil samples were determined by the established method. The vitamin E content was the highest, in which α-tocopherol and γ-tocopherol was the main tocopherol, while β-tocopherol conternt was lower. The method is simple, efficient, sensitive and reproducible. The method can be used for the separation and determination of vitamin A and vitamin E in vegetable oil.

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Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Automatica Sinica is the property of Chinese Academy of Sciences, Institute of Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

FME-SPH coupling method was applied to simulate the mechanism of rock fragmentation by TBM cutters. The 3D coupling models of rock fragmentation by single TBM cutter and two TBM cutters were established. The mechanism of rock fragmentation by TBM cutters was analyzed. The conclusions are summarized as follows: for the rock fragmentation by single TBM cutter，in the stage of the formation of the crused zone，beneath the thrust of a single cutter，microcracks extend downward to form a fan-shaped failure zone；beneath the tangential force of a single cutter，microcracks propagate forward to form the other fan-shaped failure zone. The two fan-shaped failure zones consist of a conical failure zone in rock. In the stage of the formation of microcracks，the growth rate of radial crack is faster than that of median crack. In the stage of the propagation of microcracks，the growth rate of median crack is faster than that of radial crack. When the cutter scrolls to the edge of rock，the fan-shaped failure occurs on the edge of rock. for the rock fragmentation by two TBM cutters，in the initial stage，each cutter independently acts on the rock. A conical failure zone is first formed beneath each cutter. In the stage of the formation of microcracks，the propagation direction of the Hertzian cracks between two cutters are changed because of the interaction of two cutters. In the stage of the propagation of microcracks，Hertzian cracks between the two cutters coalesce，then the rock chipping is formed. [ABSTRACT FROM AUTHOR]