We have investigated experimentally the process of a droplet impact on a regular micro-grooved surface. The target surfaces are patterned such that micro-scale spokes radiate from the center, concentric circles, and p...We have investigated experimentally the process of a droplet impact on a regular micro-grooved surface. The target surfaces are patterned such that micro-scale spokes radiate from the center, concentric circles, and parallel lines on the polishing copper plate, using Quasi-LIGA molding technology. The dynamic behavior of water droplets impacting on these structured surfaces is examined using a high-speed camera, including the drop impact processes, the maximum spreading diameters, and the lengths and numbers of fingers at different values of Weber number. Experimental results validate that the spreading processes are arrested on all target surfaces at low velocity. Also, the experimental results at higher impact velocity demonstrate that the spreading process is conducted on the surface parallel to the micro-grooves, but is arrested in the direction perpendicular to the micro-grooves. Besides, the lengths of fingers increase observably, even when they are ejected out as tiny droplets along the groove direction, at the same time the drop recoil velocity is reduced by micro-grooves which are parallel to the spreading direction, but not by micro-grooves which are vertical to the spreading direction.展开更多
Virus spread is closely related to pathogenesis.Traditional research methods of virus spread do not distinguish cell-to-cell spread from cell-free spread.The uncertainty of virus induced plaque and virus spread direct...Virus spread is closely related to pathogenesis.Traditional research methods of virus spread do not distinguish cell-to-cell spread from cell-free spread.The uncertainty of virus induced plaque and virus spread direction makes it difficult to track the spread of virus in situ.Herein,the cellular network was fabricated on the basis of PEG modification and soft lithography.Therein,cell numbers and spatial distributions we re p recisely controlled,e.g.,cellular netwo rks like "WHU" can be achieved.Furthermore,a micro-injector was combined with the cellular network for virus spread on the fixed point,in which virus spread direction was limited in one dimension.The results suggested that controllable and flexible cellular network can be constructed on the PEG pattern.The synergia of micro-injector and cellular network provides an advanced tool to investigate virus cell-to-cell spread at the initial infection stage.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51109178)the Science and Technology Innovation Foundation of Northwestern Polytechnical University,China(Grant No.JC20120218)
文摘We have investigated experimentally the process of a droplet impact on a regular micro-grooved surface. The target surfaces are patterned such that micro-scale spokes radiate from the center, concentric circles, and parallel lines on the polishing copper plate, using Quasi-LIGA molding technology. The dynamic behavior of water droplets impacting on these structured surfaces is examined using a high-speed camera, including the drop impact processes, the maximum spreading diameters, and the lengths and numbers of fingers at different values of Weber number. Experimental results validate that the spreading processes are arrested on all target surfaces at low velocity. Also, the experimental results at higher impact velocity demonstrate that the spreading process is conducted on the surface parallel to the micro-grooves, but is arrested in the direction perpendicular to the micro-grooves. Besides, the lengths of fingers increase observably, even when they are ejected out as tiny droplets along the groove direction, at the same time the drop recoil velocity is reduced by micro-grooves which are parallel to the spreading direction, but not by micro-grooves which are vertical to the spreading direction.
基金the National Science and Technology Major Project of China(No. 2018ZX10301405)the National Natural Science Foundation of China(Nos. 21775111, 21475099)
文摘Virus spread is closely related to pathogenesis.Traditional research methods of virus spread do not distinguish cell-to-cell spread from cell-free spread.The uncertainty of virus induced plaque and virus spread direction makes it difficult to track the spread of virus in situ.Herein,the cellular network was fabricated on the basis of PEG modification and soft lithography.Therein,cell numbers and spatial distributions we re p recisely controlled,e.g.,cellular netwo rks like "WHU" can be achieved.Furthermore,a micro-injector was combined with the cellular network for virus spread on the fixed point,in which virus spread direction was limited in one dimension.The results suggested that controllable and flexible cellular network can be constructed on the PEG pattern.The synergia of micro-injector and cellular network provides an advanced tool to investigate virus cell-to-cell spread at the initial infection stage.
