<正> 在碱性条件下,醛糖与酮糖之间会发生结构互变。然而美国学者Feather M S等经过十多年的研究,发现在酸性条件下,葡萄糖、甘露糖和果糖之间也有分子内的互变,并应用~3H放射标记等技术,提出了互变的反应机理,这一互变的存在给...<正> 在碱性条件下,醛糖与酮糖之间会发生结构互变。然而美国学者Feather M S等经过十多年的研究,发现在酸性条件下,葡萄糖、甘露糖和果糖之间也有分子内的互变,并应用~3H放射标记等技术,提出了互变的反应机理,这一互变的存在给寡糖及多糖的组份分析带来了一个问题,即用酸性条件水解寡糖或多糖后,如何确定其中的葡萄糖。展开更多
Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the...Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the impact of nitric acid oxidation on the surface of carbonized melamine foam and its microwave absorption properties.The treated foam exhibits optimal reflection loss of−21.51 dB at 13.20 GHz,with an effective absorption bandwidth of 7.04 GHz.The enhanced absorption properties are primarily attributed to the strengthened dielectric loss,improved impedance matching,and increased polarization losses resulting from the oxidized surfaces.This research demonstrates a promising new approach for research into surface treatments to improve the performances of microwave absorbers.展开更多
文摘<正> 在碱性条件下,醛糖与酮糖之间会发生结构互变。然而美国学者Feather M S等经过十多年的研究,发现在酸性条件下,葡萄糖、甘露糖和果糖之间也有分子内的互变,并应用~3H放射标记等技术,提出了互变的反应机理,这一互变的存在给寡糖及多糖的组份分析带来了一个问题,即用酸性条件水解寡糖或多糖后,如何确定其中的葡萄糖。
基金Project(2023RC3066)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2023JJ50079)supported by the Hunan Provincial Natural Science Foundation,China。
文摘Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the impact of nitric acid oxidation on the surface of carbonized melamine foam and its microwave absorption properties.The treated foam exhibits optimal reflection loss of−21.51 dB at 13.20 GHz,with an effective absorption bandwidth of 7.04 GHz.The enhanced absorption properties are primarily attributed to the strengthened dielectric loss,improved impedance matching,and increased polarization losses resulting from the oxidized surfaces.This research demonstrates a promising new approach for research into surface treatments to improve the performances of microwave absorbers.
