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In this work, support vector classification （SVC） algorithm was used to build structure-activity relationship （SAR） model of the 5-hydroxytryptamine type 3 （5-HT3 ） receptor antagonists with 26 compounds. In a benchmark test, SVC was compared with several techniques of machine learning currently used in the field. The prediction performance of the model was discussed on the basis of the leave-one-out cross-validation. The results show that the accuracy of prediction of SVC model was higher than those of back propagation artificial neural network （BP ANN）, K-nearest neighbor （KNN） and Fisher methods. 相似文献
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Alumina membranes without pinholes and cracks were prepared by the sol-gel process using anunordum aluminium sulphate as the starting material. The effects of different preparing conditions on morphology characteristics of the membrane were investigated by scanning electron microscopy and 3D rotational microscopy. The preparing conditions include the amounts of drying control chemical additives （DCCA）, sintering procedure and sol-gel concentration. The results showed that PVA is a good crack-preventing reagent and the morphology of supported membranes was affected by ninny factors, including Al2O3 concentration, PVA/Al2O3 ratio, heating rate, membrane thickness and intrinsic defects of the substrate surface. 相似文献
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1 Introduction The 5-hydroxytryptamine type 3 (5-HT3) receptorantagonists[1-2]are currently used in the treatment ofchemotherapy and radiotherapy induced emesis . Thecompounds are based onthe parent structure showninFig.1 ,the aromatic systems include mono- and bicy-clic rings ,with or without heteroatoms ,and with vari-ous substitution patterns .This range of structural vari-ation makes it difficult to treat the analysis of thesecompounds .Fig .1 Parent structure of 5-HT3antagonists With t… 相似文献
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化学是一门实验科学,学化学而完全不做实验,是难于学好的。由于“四人帮”破坏,许多中学化学实验室荡然无存,一时难于完全恢复。 这使我回忆起小时候自学化学的情况。那时家里较穷,而且当时极难买到化学药品(包括三酸二碱)。我们几个小朋友利用石灰、碱、明矾、肥皂、食盐、石膏、铝币、卤水、煤炭、蜡烛等当原料,用砂锅、煤球炉、酒瓶当化学仪器,也能做不少实验,下面是一些例子: 相似文献
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