We provide a way to precisely control the geometry of a SiNx nanopore by adjusting the applied electric pulse. The pore is generated by applying the current pulse across a SiNx membrane, which is immersed in potassium...We provide a way to precisely control the geometry of a SiNx nanopore by adjusting the applied electric pulse. The pore is generated by applying the current pulse across a SiNx membrane, which is immersed in potassium chloride solution. We can generate single conical and cylindrical pores with different electric pulses. A theoretical model based on the Poisson and Nernst-Planck equations is employed to simulate the ion transport properties in the channel. In turn, we can analyze pore geometries by fitting the experimental current-voltage （I-V） curves. for the conical pores with a pore size of 0.5-2nm in diameter, the slope angles are around -2.5% to -10%. Moreover, the pore orifice can be enlarged slightly by additional repeating pulses. The conic pore lumen becomes close to a cylindrical channel, resulting in a symmetry I-V transport under positive and negative biases. A qualitative understanding of these effects will help us to prepare useful solid-nanopores as demanded.展开更多
Network densification is a promising solution to fulfill network capacity requirement and transmission rate for beyond 5G and 6G wireless communications.Ultra-dense network(UDN)integrates heterogeneous network resourc...Network densification is a promising solution to fulfill network capacity requirement and transmission rate for beyond 5G and 6G wireless communications.Ultra-dense network(UDN)integrates heterogeneous network resources and coordinates technologies on quality of service controlling,to provide users with flexible service.However,dense deployment reduces coverage radius of the cell,resulting in an increase on handover frequency,which makes a serious impact on service continuity.In this paper,we propose a proactive selection method for dynamic access points grouping(DAPGing)in accordance with“user-centric”philosophy,which selects target Access Points(AP)and reduces handover times to ensure communication continuity.This method includes two criteria:1)the user’s sojourn time,which is determined by analyzing the AP coverage area;2)neighbor relationship between APs,which is determined by coverage area and signal strength characteristics between neighboring APs.Therefore,candidate APs become the proactive selected ones to update the AP group.Stochastic geometry is used to build system model and performance metrics are analyzed,including AP group coverage probability and average update frequency.Experimental analysis shows that the proposed proactive selection method brings similar coverage probability to traditional handover method,while average update frequency is reduced more than 20%selection criteria.展开更多
Using the underwater acoustic channel(UWA)for information dissemination requires a high data rate.However,some phenomena like refraction,reflection,phase shift,and high attenuation are undesirably apparent when the su...Using the underwater acoustic channel(UWA)for information dissemination requires a high data rate.However,some phenomena like refraction,reflection,phase shift,and high attenuation are undesirably apparent when the subject of using UWA is raised.Accordingly,sound communication would be a highly challenging task to be accomplished.Therefore,proposing a model of acoustic underwater communication channels is critical because of the multipath interference originating from the surface and bottom of the ocean.In this contribution,a straightforward geometry channel model for vertical and horizontal marine communications is presented.To do so,transmission loss and channel impulse response are analyzed as a function of transmitter and receiver distance,water depth,and reflection rate.The results of the model proposed in this paper are in very good agreement with those available in the literature.Initial findings indicate that the delay spread of horizontal communication with a 1000 m range reaches79 ms and 0.3 s for 30 m vertical communication.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61471336,51503207 and 61504146the Joint-Scholar of West Light Foundation of Chinese Academy of Sciences
文摘We provide a way to precisely control the geometry of a SiNx nanopore by adjusting the applied electric pulse. The pore is generated by applying the current pulse across a SiNx membrane, which is immersed in potassium chloride solution. We can generate single conical and cylindrical pores with different electric pulses. A theoretical model based on the Poisson and Nernst-Planck equations is employed to simulate the ion transport properties in the channel. In turn, we can analyze pore geometries by fitting the experimental current-voltage （I-V） curves. for the conical pores with a pore size of 0.5-2nm in diameter, the slope angles are around -2.5% to -10%. Moreover, the pore orifice can be enlarged slightly by additional repeating pulses. The conic pore lumen becomes close to a cylindrical channel, resulting in a symmetry I-V transport under positive and negative biases. A qualitative understanding of these effects will help us to prepare useful solid-nanopores as demanded.
基金This work was supported by the National Natural Science Foundation of China(NSFC)under Grant 61931005.
文摘Network densification is a promising solution to fulfill network capacity requirement and transmission rate for beyond 5G and 6G wireless communications.Ultra-dense network(UDN)integrates heterogeneous network resources and coordinates technologies on quality of service controlling,to provide users with flexible service.However,dense deployment reduces coverage radius of the cell,resulting in an increase on handover frequency,which makes a serious impact on service continuity.In this paper,we propose a proactive selection method for dynamic access points grouping(DAPGing)in accordance with“user-centric”philosophy,which selects target Access Points(AP)and reduces handover times to ensure communication continuity.This method includes two criteria:1)the user’s sojourn time,which is determined by analyzing the AP coverage area;2)neighbor relationship between APs,which is determined by coverage area and signal strength characteristics between neighboring APs.Therefore,candidate APs become the proactive selected ones to update the AP group.Stochastic geometry is used to build system model and performance metrics are analyzed,including AP group coverage probability and average update frequency.Experimental analysis shows that the proposed proactive selection method brings similar coverage probability to traditional handover method,while average update frequency is reduced more than 20%selection criteria.
文摘Using the underwater acoustic channel(UWA)for information dissemination requires a high data rate.However,some phenomena like refraction,reflection,phase shift,and high attenuation are undesirably apparent when the subject of using UWA is raised.Accordingly,sound communication would be a highly challenging task to be accomplished.Therefore,proposing a model of acoustic underwater communication channels is critical because of the multipath interference originating from the surface and bottom of the ocean.In this contribution,a straightforward geometry channel model for vertical and horizontal marine communications is presented.To do so,transmission loss and channel impulse response are analyzed as a function of transmitter and receiver distance,water depth,and reflection rate.The results of the model proposed in this paper are in very good agreement with those available in the literature.Initial findings indicate that the delay spread of horizontal communication with a 1000 m range reaches79 ms and 0.3 s for 30 m vertical communication.
