The dense gas flow and heat transfer in micro- and nano-channels was simulated using the Enskog simulation Monte Carlo (ESMC) method. The results were compared with those from the direct simulation Monte Carlo (DSMC) ...The dense gas flow and heat transfer in micro- and nano-channels was simulated using the Enskog simulation Monte Carlo (ESMC) method. The results were compared with those from the direct simulation Monte Carlo (DSMC) method and from the consistent Boltzmann algorithm (CBA). The dense gas flow and heat transfer characteristics were thus analyzed. The results showed that when the gas density was large enough, the finite gas density effect on the flow and heat transfer cannot be ignored, which decreased the skin friction coefficient and changed the heat transfer characteristics on the channel wall surfaces.展开更多
This paper studies the flow characteristics in micro/nano-channels subjected to an applied electric field. The nano-channel flow was observed by means of the fluorescence Calcein. A Fluorescence Concentration Gradient...This paper studies the flow characteristics in micro/nano-channels subjected to an applied electric field. The nano-channel flow was observed by means of the fluorescence Calcein. A Fluorescence Concentration Gradient Interface （FCGI） was observed across the nano-channel array. The front of the FCGI was shown to have an analogous parabolic shape. The propagation of this interface reflects indirectly the induced pressure at the micro/nano-channel junction, where the enrichment-depletion processes are known to take place. This induced pressure was predicted by numerical simulations, and this paper gives the first experimental evidence.展开更多
Numerical simulation of injection of polyethylene fluid in a variable cross-section nano-channel was carried out using the molecular dynamics method.The effects of the nano-channel cross-section and the external force...Numerical simulation of injection of polyethylene fluid in a variable cross-section nano-channel was carried out using the molecular dynamics method.The effects of the nano-channel cross-section and the external force on the rheological behavior and structural properties of the polyethylene fluid were investigated.It was found that an absorbed layer appeared near the wall and the thickness of the absorbed layer increased with increasing cone angle of the nano-channel.The injection distance of the polyethylene fluid decreased with increasing cone angle and decreasing external force.In the nano-channel with cone angle 45°,polyethylene particles uniformly filled the whole channel and were stretched along the flow direction.Uniaxial stretching of particles was enhanced when the external force was strengthened,which facilitates injection of the polyethylene fluid into the nano-channel.展开更多
Enhancing ion conductance and controlling transport pathway in organic electrolyte could be used to modulate ionic kinetics to handle signals. In a Pt/Poly(3-hexylthiophene-2,5-diyl)/Polyethylene?Li CF3SO3/Pt hetero-j...Enhancing ion conductance and controlling transport pathway in organic electrolyte could be used to modulate ionic kinetics to handle signals. In a Pt/Poly(3-hexylthiophene-2,5-diyl)/Polyethylene?Li CF3SO3/Pt hetero-junction, the electrolyte layer handled at high temperature showed nano-fiber microstructures accompanied with greatly improved salt solubility. Ions with high mobility were confined in the nano-fibrous channels leading to the semiconducting polymer layer,which is favorable for modulating dynamic doping at the semiconducting polymer/electrolyte interface by pulse frequency.Such a device realized synaptic-like frequency selectivity, i.e., depression at low frequency stimulation but potentiation at high-frequency stimulation.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant No.59995550-2)theNational Key Basic Research and Development Program of China(Grant No.1999033106).
文摘The dense gas flow and heat transfer in micro- and nano-channels was simulated using the Enskog simulation Monte Carlo (ESMC) method. The results were compared with those from the direct simulation Monte Carlo (DSMC) method and from the consistent Boltzmann algorithm (CBA). The dense gas flow and heat transfer characteristics were thus analyzed. The results showed that when the gas density was large enough, the finite gas density effect on the flow and heat transfer cannot be ignored, which decreased the skin friction coefficient and changed the heat transfer characteristics on the channel wall surfaces.
基金supported by the Chinese Academy of Sciences Research and Development Program of China(Grant No.KJCX2-YW-H18)the National Natural Science Foundation of China(Grant No.10872203)the National Key Basic Research Development Program of China(973Program,Grant No2007CB714501)
文摘This paper studies the flow characteristics in micro/nano-channels subjected to an applied electric field. The nano-channel flow was observed by means of the fluorescence Calcein. A Fluorescence Concentration Gradient Interface （FCGI） was observed across the nano-channel array. The front of the FCGI was shown to have an analogous parabolic shape. The propagation of this interface reflects indirectly the induced pressure at the micro/nano-channel junction, where the enrichment-depletion processes are known to take place. This induced pressure was predicted by numerical simulations, and this paper gives the first experimental evidence.
基金supported by the National Natural Science Foundation of China (50876119)
文摘Numerical simulation of injection of polyethylene fluid in a variable cross-section nano-channel was carried out using the molecular dynamics method.The effects of the nano-channel cross-section and the external force on the rheological behavior and structural properties of the polyethylene fluid were investigated.It was found that an absorbed layer appeared near the wall and the thickness of the absorbed layer increased with increasing cone angle of the nano-channel.The injection distance of the polyethylene fluid decreased with increasing cone angle and decreasing external force.In the nano-channel with cone angle 45°,polyethylene particles uniformly filled the whole channel and were stretched along the flow direction.Uniaxial stretching of particles was enhanced when the external force was strengthened,which facilitates injection of the polyethylene fluid into the nano-channel.
基金supported by National Natural Science foundation of China (Grant Nos. 51371103 and 51231004)National Basic Research Program of China (Grant No. 2010CB832905)+1 种基金National Hi-tech (R&D) Project of China (Grant Nos. 2012AA03A706, 2013AA030801)the Research Project of Chinese Ministry of Education (No. 113007A)
文摘Enhancing ion conductance and controlling transport pathway in organic electrolyte could be used to modulate ionic kinetics to handle signals. In a Pt/Poly(3-hexylthiophene-2,5-diyl)/Polyethylene?Li CF3SO3/Pt hetero-junction, the electrolyte layer handled at high temperature showed nano-fiber microstructures accompanied with greatly improved salt solubility. Ions with high mobility were confined in the nano-fibrous channels leading to the semiconducting polymer layer,which is favorable for modulating dynamic doping at the semiconducting polymer/electrolyte interface by pulse frequency.Such a device realized synaptic-like frequency selectivity, i.e., depression at low frequency stimulation but potentiation at high-frequency stimulation.
