复合材料的交联密度高,使其摩擦磨损性能较差,所以需要对其进行改性来提高摩擦磨损性能。通过Cite Space V对近10年国内外以“复合材料”和“摩擦磨损”为主题的文献进行知识图谱可视化分析。结果表明:该领域研究主要集中于中国、印度...复合材料的交联密度高,使其摩擦磨损性能较差,所以需要对其进行改性来提高摩擦磨损性能。通过Cite Space V对近10年国内外以“复合材料”和“摩擦磨损”为主题的文献进行知识图谱可视化分析。结果表明:该领域研究主要集中于中国、印度和俄罗斯等国家。复合材料改性的主要工艺为共聚改性和共混改性。常见的柔性分子添加剂包括超高分子量聚乙烯、二氧化硅、碳化硅和聚四氟乙烯等。目前复合材料的研究热点有环氧树脂、聚氨酯、聚醚醚酮和聚酰亚胺等。分析过程中也发现柔性链改性中存在的一些问题,为后续提供一定研究方向。展开更多
A density functional theory （DFT） is used to investigate molecular orientation of hard rod fluids in a hard slit. The DFT approach combines a modified fundamental measure theory （MFMT） for excluded-volume effect w...A density functional theory （DFT） is used to investigate molecular orientation of hard rod fluids in a hard slit. The DFT approach combines a modified fundamental measure theory （MFMT） for excluded-volume effect with the first order thermodynamics perturbation theory for chain connectivity. In the DFT approach, the intra-molecular bonding orientation function is introduced. We consider the effects of molecular length （i.e. aspect ratio of rod） and packing fraction on the orientations of hard rod fluids and flexible chains. For the flexible chains, the chain length has no significant effect while the packing fraction shows slight effect on the molecular orientation distribution. In contrast, for the hard rod fluids, the chain length determines the molecular orientation distribution, while the packing fraction has no significant effect on the molecular orientation distribution. By making a comparison between molecular orientations of the flexible chain and the hard rod fluid, we find that the molecular stiffness distinctly affects the molecular orientation. In addition, partitioning coefficient indicates that the longer rodlike molecule is more difficult to enter the confined phase, especially at low bulk packing fractions.展开更多
Mono 3 -deoxy-(N' -benzoyl-ethylenediamino)-β -CD, mono 3 -deoxy-(N' -benzimidoyl -ethylamino)-β-CD, and mono 3 -deoxy-(N' - salicylidene-ethylenediamino)- β -CD, each of which has a flexible chain that...Mono 3 -deoxy-(N' -benzoyl-ethylenediamino)-β -CD, mono 3 -deoxy-(N' -benzimidoyl -ethylamino)-β-CD, and mono 3 -deoxy-(N' - salicylidene-ethylenediamino)- β -CD, each of which has a flexible chain that bonds the aryl moiety on the secondary side of β-CD, were prepared inthis research. The reaction processes might involve the formation of mono(2, 3 -manno-epoxide )- β -CD as an intermediate in our reaction conditions.展开更多
文摘复合材料的交联密度高,使其摩擦磨损性能较差,所以需要对其进行改性来提高摩擦磨损性能。通过Cite Space V对近10年国内外以“复合材料”和“摩擦磨损”为主题的文献进行知识图谱可视化分析。结果表明:该领域研究主要集中于中国、印度和俄罗斯等国家。复合材料改性的主要工艺为共聚改性和共混改性。常见的柔性分子添加剂包括超高分子量聚乙烯、二氧化硅、碳化硅和聚四氟乙烯等。目前复合材料的研究热点有环氧树脂、聚氨酯、聚醚醚酮和聚酰亚胺等。分析过程中也发现柔性链改性中存在的一些问题,为后续提供一定研究方向。
基金Project supported by the National Natural Science Foundation of China （Grant No 20646001）, the Beijing Novel Program （Grant No 2006B17）, the Program for New Century Excellent Talents in University （NCET）, the ＂Chemical Grid Program＂ and the Excellent Talent Fund of Beijing University of Chemical Technology.
文摘A density functional theory （DFT） is used to investigate molecular orientation of hard rod fluids in a hard slit. The DFT approach combines a modified fundamental measure theory （MFMT） for excluded-volume effect with the first order thermodynamics perturbation theory for chain connectivity. In the DFT approach, the intra-molecular bonding orientation function is introduced. We consider the effects of molecular length （i.e. aspect ratio of rod） and packing fraction on the orientations of hard rod fluids and flexible chains. For the flexible chains, the chain length has no significant effect while the packing fraction shows slight effect on the molecular orientation distribution. In contrast, for the hard rod fluids, the chain length determines the molecular orientation distribution, while the packing fraction has no significant effect on the molecular orientation distribution. By making a comparison between molecular orientations of the flexible chain and the hard rod fluid, we find that the molecular stiffness distinctly affects the molecular orientation. In addition, partitioning coefficient indicates that the longer rodlike molecule is more difficult to enter the confined phase, especially at low bulk packing fractions.
文摘Mono 3 -deoxy-(N' -benzoyl-ethylenediamino)-β -CD, mono 3 -deoxy-(N' -benzimidoyl -ethylamino)-β-CD, and mono 3 -deoxy-(N' - salicylidene-ethylenediamino)- β -CD, each of which has a flexible chain that bonds the aryl moiety on the secondary side of β-CD, were prepared inthis research. The reaction processes might involve the formation of mono(2, 3 -manno-epoxide )- β -CD as an intermediate in our reaction conditions.
