排序方式: 共有10条查询结果,搜索用时 15 毫秒
1
1.
2.
3.
4.
本实验采用Schaal烘箱加速实验法,在Design Expert软件中的三因素三水平实验基础上,以过氧化值(POV值)作为油脂稳定性的评价指标,研究茶多酚、番茄红素、柠檬酸三种天然复合抗氧化剂对藻油DHA抗氧化性能的影响。利用响应面分析法,建立了影响过氧化值的主要因素的二次多项数学模型,其二次回归方程的决定系数达到0.9728。结果表明,茶多酚、番茄红素、柠檬酸三种天然抗氧化剂中,番茄红素对过氧化值线性效应一般显著,茶多酚和柠檬酸交互作用对过氧化值线性效应高度显著。由Design Expert软件优化得到21组抗氧化剂复配组合,并最终确定最优配比为:番茄红素0.04‰,柠檬酸0.30‰,茶多酚0.12‰,理论过氧化值为0.094。最后利用水平验证实验进行了验证,其过氧化值为0.092,与理论值误差为2.13%,表明实验值与预测值之间拟合性好。 相似文献
5.
In gas-liquid mass transfer processes,Marangoni convection may occur due to the surface tension gradient produced by mass transfer near the interface.With a falling soap film tunnel and the Schlieren optical method,the Marangoni convection patterns along the film surface were observed directly in the desorption process of acetone from the falling soap film.The Schlieren images showed the regular roll convection in the thin falling soap film during the acetone desorption.The hydraulic characteristics were determined experimentally by measuring the variation of acetone concentration in the film and the surface tension of the soap liquid.The results show that the acetone concentration gradient vertical to the falling direction is very small because the thickness of the soap film is in the order of 10-6 m.The variation of acetone concentration along the falling film is large,so there is a significant surface tension gradient,resulting in the Marangoni roll convection.The experimental results and a qualitative analysis may be helpful to understand the mechanism of Marangoni convection near the interface in the mass transfer. 相似文献
6.
In gas-liquid mass transfer processes,interfacial turbulence may occur due to the surface tension gradient and the density gradient produced by mass transfer near the interface.The interfacial turbulence can enhance the mass transfer since it intensifies the movement of interfacial fluid.By means of the shadowgraph optical method,the interfacial turbulence patterns vertical to the interface were observed directly in the volatilization process of binary systems.The images of the amplified interfacial turbulence showed the variation of concentration and the fluid movement under the interface.Two patterns of interfacial turbulence were observed in the experiments:plume and vortex.With the plume,the interfacial fluid moved slowly and penetrated the liquid deeply.With the vortex,the interfacial turbulence occurred in the vicinity of the liquid interface and the fluid moves quite fast.A qualitative analysis was carried out based on the mechanism of Rayleigh-Bénard convection induced by density gradient and Marangoni convection induced by surface tension gradient. 相似文献
7.
龙须菜提取琼胶碱处理工艺条件优化 总被引:5,自引:0,他引:5
为研究高温稀碱处理条件与龙须菜琼胶理化性质间的关系,利用正交试验研究了碱液浓度、碱处理温度和碱处理时间三因素与龙须菜琼胶理化性质间的定量关系。通过综合出胶率、硫酸基含量和3,6-内醚-半乳糖含量的实验结果,得出三组最佳处理条件,再经验证试验,并最终由琼胶的凝胶强度确定碱处理的最佳工艺条件为:碱液浓度为6%,碱处理温度为80℃,碱处理时间为120min。为提高龙须菜琼胶加工质量、降低成本提供了重要科学依据。 相似文献
8.
4-羟基香豆素的合成工艺改进 总被引:1,自引:0,他引:1
以邻羟基苯乙酮与碳酸二甲酯为原料,甲醇钠与聚乙二醇-400为催化剂合成了标题化合物,考察了甲醇钠用量、聚乙二醇-400用量、反应时间、反应温度等因素对反应结果的影响。确定最佳工艺条件为:以二甲苯为溶剂,原料物质的量比为:n(邻羟基苯乙酮)∶n(碳酸二甲酯)∶n(甲醇钠)∶n(聚乙二醇-400)=1∶2.0∶2.5∶0.28,120℃反应2 h,反应结束后加水,水相酸化至pH1.0~1.5,4-羟基香豆素的收率56.9%。产物经熔点、IR、1HNMR、13CNMR进行确认。 相似文献
9.
10.
研究了硼酸加入量对所合成硼改性酚醛树脂性能的影响。通过红外光谱和热重等分析手段对硼改性酚醛树脂的结构和热性能进行表征,分别考察其在氮气和空气氛围下的残炭率,获知当苯酚、甲醛和硼酸之间的物质的量比为1∶1.4∶0.4时,硼改性酚醛树脂的残炭率最高,分别为67.82%和10.92%。此外,以硼改性酚醛树脂为基体树脂制备模塑料并考察其拉伸强度、弯曲强度和抗冲击强度等力学性能。综合考虑以上热性能和力学性能,确定苯酚、甲醛和硼酸之间的最佳物质的量比为1∶1.4∶0.3。最后,研究了添加不同种类和不同含量的填料对酚醛模塑料力学性能的影响。研究结果表明:以短玻璃纤维为填料时,酚醛模塑料的力学性能优于木粉和长玻璃纤维混合物填料;若使用木粉和长玻璃纤维混合物填料,当木粉与长玻璃纤维的质量比为1∶3时,酚醛模塑料的力学性能最佳。 相似文献
1