The assembled structures of triangular symmetrically shape molecules with three functional groups, trimesic acid (TMA) and melamine, have been investigated by scanning tunneling microscopy on Highly Oriented Pyrolytic Graphite (HOPG) in ambient. Hexagonal porous structures are formed by these molecules and the cavity of the assembled structure becomes bigger when larger molecules are used as building blocks. The cavity within the assembled structure formed by TMA is bigger enough to host guest molecule.
Juze Xie,Yangting Ou,Jiawen Yao,Tianxin Luan,Taosheng Zhang,Zhehan Li,Chufeng Sun,Jisheng Pan
The chemical mechanical polishing (CMP) of single-crystal silicon carbide (SiC) faces challenges such as low efficiency and limited service life of the polishing liquid. To address these issues, we encapsulated the Fenton reaction catalyst FeSO 4 within melaminated formaldehyde (MF) resin via in-situ polymerization to form microcapsules. During processing, when these microcapsules come into contact with the workpiece surface, they release Fe 2+ ions that participate in the reaction, generating highly oxidizing species that promote efficient interfacial chemical reactions. Compared with other catalysts like Fe 3 O 4 and Fe-C composites, FeSO 4 exists in the polishing slurry as Fe 2+ , which significantly enhances the efficiency of the Fenton reaction. This study systematically investigates the effects of various process parameters (water-oil ratio, stirring rate, core-wall ratio) on the morphology and particle size distribution of FeSO 4 microcapsules. The results demonstrate that under conditions of a water-oil ratio of 1:25, a stirring rate of 450 rpm, and a core-wall ratio of 1:2, the prepared microcapsules exhibit smooth surfaces, uniform particle sizes, and excellent dispersion properties. When the core-wall ratio decreases from 1:1 to 1:3, the permeation resistance of the microcapsules increases by approximately 1.5 times. Fourier Transform Infrared spectroscopy (FT-IR) confirms the encapsulation of FeSO 4 within MF resin. Thermogravimetric analysis (TGA) reveals the good thermal stability of the microcapsules. Friction and wear test results indicate that the wear area under FeSO 4 microcapsule conditions is 12.491 μm², representing a 30 % increase in material removal rate compared to traditional Fenton reaction catalysts.
危险品化学品经营许可证（带存储）