响应面法优化蒙山莴苣黄酮的提取研究

采用乙醇浸提法提取蒙山莴苣黄酮,将单因素实验与响应面优化法优化实验结合起来,确定蒙山莴苣黄酮的最佳提取条件。结果表明,蒙山莴苣最佳提取条件为乙醇体积分数70%、液料比40 mL/g、水浴温度74℃、水浴时间3.2 h。在此条件下,黄酮得率为37.06 mg/g,与模型预测值接近,表明由本法得到的模型对黄酮得率具有较好的预测能力。     

阳离子可染涤纶短纤维原丝纺丝工艺

通过对阳离子可染聚酯 (CDP)熔体性质的分析 ,综合阳离子可染涤纶短纤维后处理对原丝可纺性的要求 ,对纺丝工艺进行优化 ,选择纺丝温度 2 86℃ ,喷丝孔剪切速率 6.448× 10 3s- 1 ,箱体入口压力 4MPa ,可实现DMT法直纺CDP短纤维工业化生产     

薤白多糖的提取及体外抗氧化活性研究

用热水浸提法提取薤白中的生物多糖,采用响应面法对提取条件进行优化,并研究了薤白多糖的体外抗氧化活性。结果表明,最佳提取条件为:提取温度72℃,提取时间1.5 h,液料比20∶1 m L/g,薤白多糖提取率(5.26±0.014)%。薤白多糖具有一定的体外抗氧化能力,但活性低于同浓度的Vc,其中薤白多糖对羟基自由基的清除能力相对较强,IC50值为1 591.7μg/m L;对超氧阴离子自由基的清除能力及对Fe3+的还原能力较弱。     

The effects of dilution gas on nanoparticle growth in atmospheric-pressure acetylene microdischarges

A two-dimensional multi-fluid model is developed to investigate the effects of dilution gas on microplasma properties and nanoparticle behavior in atmospheric-pressure radio-frequency acetylene discharges. The percentage of dilution gases (argon and helium) percentage varied from 0% to 90%, with the pressure kept constant. Simulation results show that the dilution gas percentage has a significant influence on the spatial distributions of the electron density and temperature, as well as on the formation of nanoparticles in acetylene microplasmas. With increasing dilution gas percentage, the electron density profile changes continuously from being high at the edge to high in the center. A mode transition from a mixed discharge mode with both α regime and drift-ambipolar regime into α regime occurs, which is associated with a sudden decrease in the electron density of the presheaths and an increase in the electron temperature of the bulk plasma. The mode transition point corresponds to the lowest number density ratio of hydrocarbon ions to acetylene. The highest number density ratio is observed at a dilution percentage of 90%, and causes more effective nucleation and coagulation of nanoparticles. Furthermore, owing to the high ionization potential of helium, the transition point moves to a larger dilution gas percentage in ${{\rm{C}}}_{2}{{\rm{H}}}_{2}$/He microplasmas. Finally, the growth of nanoparticles via coagulation is studied.