Three-dimensional (3D) covalent organic frameworks (COFs) are crystalline porous polymers with potential in numerous high-tech applications, but the linkages involved in their synthesis are still rather limited. Herein, we report novel 3D sp 2 carbon-linked COFs fabricated by the formation reaction of C=C bonds and their application in fluorescence imaging. These new COFs, namely JUC-580 and JUC-581, show high stability and excellent light-emitting properties in solid state and dispersed in various solvents. Furthermore, we investigate the potential application of JUC-581 as a drug carrier combined with fluorescence imaging. These results indicate that 3D sp 2 carbon-linked COFs are not only potential drug-loaded and sustained release materials but also promising cell fluorescent stains. This study thus expands the structural categories of 3D COFs based on different linkages, and promotes their prospective applications for biomedicine and fluorescent materials.
In order to predict the physical characteristics of the large vibrating screen from its scale-down model, the similarity ratios of the frequency response functions, mode shapes, and dynamic stresses between the prototype and the scale model screen are built according to the similarity theory. The natural frequencies and modal shapes are extracted from the frequency response function by means of modal tests, in which the relative error of the natural frequencies is less than 9% and the modal shapes are consistent between the prototype and the model. The operating condition parameters including dynamic stress, displacement, velocity, and acceleration were also measured and conform to the similarity criteria. The results show that the inherent and operating condition parameters of the large vibrating screen can be obtained from the scale-down model conveniently, which provides an effective method for structural optimization and substructure coupling analysis of the large vibrating screen.
Covalent organic frameworks (COFs) have attracted extensive interests due to their unique structures and various applications. However, structural diversities are still limited, which greatly restricts the development of COF materials....
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