还原氧化石墨烯横向尺寸分布影响因素初探

化学还原剥离氧化石墨法制备的还原氧化石墨烯具有诸多优异性能,但所得还原氧化石墨烯横向尺度差异较大.利用化学还原法制备了还原氧化石墨烯,基于还原氧化石墨烯的AFM观测结果,初步统计分析了静置、磁力搅拌、离心和超声处理及它们的次序对还原氧化石墨烯横向尺寸分布的影响,结果表明后述3个步骤及次序是影响斑点状(横向尺寸＜100nm×100nm)和树叶状(横向尺寸＞500nm×500nm)还原氧化石墨烯横向尺寸分布的主要因素.     

Continuous centrifugal fractionation of egg yolk granules and plasma constituents influenced by process conditions and product characteristics

The egg yolk main fractions, granules and plasma, show considerable different emulsifying properties. In order to use this potential, the present study investigates the influence of variable process conditions on the continuous centrifugal separation process of liquid egg yolk. It is shown that the granule fraction represents no homogeneous component, but consists of three different subfractions with different size, density and structure. It was confirmed by SDS–PAGE that each granule subfraction incorporated different amounts of LDL. The inhomogeneity leads to a subfraction depending sedimentation behaviour of the whole granule-fraction in egg yolk which could be clearly classified. Based on these findings, the impact of variable rheological properties on the sedimentation behaviour of polydisperse suspensions with high particle concentrations is discussed. However, fluid temperatures of 50 °C, a dry matter reduction below 29% prior to the centrifugal fractionation and g-forces up to 10,000g resulted in excellent separation efficiencies of the granule-fraction.