Fluid manipulation is very important in any lab-on-a-chip system. This paper analyses phenomena which use the alternating current （AC） electric field to deflect and manipulate coflowing streams of two different elec...Fluid manipulation is very important in any lab-on-a-chip system. This paper analyses phenomena which use the alternating current （AC） electric field to deflect and manipulate coflowing streams of two different electrolytes （with conductivity gradient） within a microfluidic channel. The basic theory of the electrohydrodynamics and simulation of the analytical model are used to explain the phenomena. The velocity induced for different voltages and conductivity gradient are computed. The results show that when the AC electrical signal is applied on the electrodes, the fluid with higher conductivity occupies a larger region of the channel and the interface of the two fluids is deflected. It will provide some basic reference for people who want to do more study in the control of different fluids with conductivity gradient in a microfluidic channel.展开更多
Nanofluidics in hydrophilic nanopores is a common issue in many natural and industrial processes. Among all,the mass transport of nanofluidics is most concerned. Besides that, the heat transfer of a fluid flow in nano...Nanofluidics in hydrophilic nanopores is a common issue in many natural and industrial processes. Among all,the mass transport of nanofluidics is most concerned. Besides that, the heat transfer of a fluid flow in nano or micro channels is always considered with adding nanoparticles into the flow, so as to enhance the heat transfer by convection between the fluid and the surface. However, for some applications with around 1 nm channels such as nano filtration or erosion of rocks, there should be no nanoparticles included. Hence, it is necessary to figure out the heat transfer mechanism in the single phase nanofluidics. Via non-equilibrium molecular dynamics simulations, we revealed the heat transfer inside nanofluidics and the one between fluid and walls by setting simulation into extremely harsh condition. It was found that the heat was conducted by molecular motion without temperature gradient in the area of low viscous heat, while it was transferred to the walls by increasing the temperature of fluids. If the condition back to normal, it was found that the viscous heat of nanofluidics could be easily removed by the fluid-wall temperature drop of less than 1 K.展开更多
Gas-insulated transmission lines and switchgears(GILs/GISs)are essential components that constitute ultra-high-voltage power transmission and transformation systems.Epoxy-based insulators,as core components,experience...Gas-insulated transmission lines and switchgears(GILs/GISs)are essential components that constitute ultra-high-voltage power transmission and transformation systems.Epoxy-based insulators,as core components,experience significant electric field distortions and consequent flashover faults.Since the 1980s,researchers have focused on utilizing dielectric functionally graded materials(FGMs)to improve the electric field distribution of insulators.The key research on FGMs for GIL/GIS insulators over the past half-century is reviewed.The development from bulk-FGMs to surface-FGMs,and eventually to multi-FGMs are outlined.Bulk-FGMs are typically used in AC systems.These materials provide a more uniform electric field distribution by creating a gradient in the relative permittivity within the insulator’s bulk.Surface-FGMs are commonly employed in DC systems,and they regulate the electric field by designing a surface conductivity gradient,thus preventing internal breakdowns that result from bulk conductivity gradients.In practice,GIL/GIS insulators are exposed to complex operating conditions,including AC,DC,and transient voltages,resulting in the development of multi-FGMs.These combine both conductivity and permittivity gradients,thus providing a comprehensive solution for suppressing both dynamic and static electric field distortions.An effective reference for researchers and industry professionals to support the transition of the research on FGM insulators from laboratory studies to practical engineering applications is provided.展开更多
Due to their rich and adjustable porous network structure,paper-based functional materials have become a research hotspot in the field of energy storage.However,reasonably designing and making full use of the rich por...Due to their rich and adjustable porous network structure,paper-based functional materials have become a research hotspot in the field of energy storage.However,reasonably designing and making full use of the rich pore structure of paper-based materials to improve the electrochemical performance of paper-based energy storage devices still faces many challenges.Herein,we propose a structure engineering technique to develop a conductive integrated gradient porous paper-based(CIGPP)supercapacitor,and the kinetics process for the influence of gradient holes on the electrochemical performance of the CIGPP is investigated through experimental tests and COMSOL simulations.All results indicate that the gradient holes endow the CIGPP with an enhanced electrochemical performance.Specifically,the CIGPP shows a significant improvement in the specific capacitance,displays rich frequency response characteristics for electrolyte ions,and exhibits a good rate performance.Also,the CIGPP supercapacitor exhibits a low self-discharge and maintains a stable electrochemical performance in different electrolyte environments because of gradient holes.More importantly,when the CIGPP is used as a substrate to fabricate a CIGPP-PANI hybrid,it still maintains good electrochemical properties.In addition,the CIGPP supercapacitor also shows excellent stability and sensitivity for monitoring human motion and deaf-mute voicing,showing potential application prospects.This study provides a reference and feasible way for the design of structure-engineered integrated paper-based energy storage devices with outstanding comprehensive electrochemical performance.展开更多
基金Project supported by the 111 Project (Grant No B07018)
文摘Fluid manipulation is very important in any lab-on-a-chip system. This paper analyses phenomena which use the alternating current （AC） electric field to deflect and manipulate coflowing streams of two different electrolytes （with conductivity gradient） within a microfluidic channel. The basic theory of the electrohydrodynamics and simulation of the analytical model are used to explain the phenomena. The velocity induced for different voltages and conductivity gradient are computed. The results show that when the AC electrical signal is applied on the electrodes, the fluid with higher conductivity occupies a larger region of the channel and the interface of the two fluids is deflected. It will provide some basic reference for people who want to do more study in the control of different fluids with conductivity gradient in a microfluidic channel.
基金Supported by the National Basic Research Program of China(2015CB655301)the National Natural Science Foundation of China(21506091)+2 种基金the Jiangsu Natural Science Foundations(BK20150944)the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Nanofluidics in hydrophilic nanopores is a common issue in many natural and industrial processes. Among all,the mass transport of nanofluidics is most concerned. Besides that, the heat transfer of a fluid flow in nano or micro channels is always considered with adding nanoparticles into the flow, so as to enhance the heat transfer by convection between the fluid and the surface. However, for some applications with around 1 nm channels such as nano filtration or erosion of rocks, there should be no nanoparticles included. Hence, it is necessary to figure out the heat transfer mechanism in the single phase nanofluidics. Via non-equilibrium molecular dynamics simulations, we revealed the heat transfer inside nanofluidics and the one between fluid and walls by setting simulation into extremely harsh condition. It was found that the heat was conducted by molecular motion without temperature gradient in the area of low viscous heat, while it was transferred to the walls by increasing the temperature of fluids. If the condition back to normal, it was found that the viscous heat of nanofluidics could be easily removed by the fluid-wall temperature drop of less than 1 K.
基金Supported by the Smart Gird-National Science and Technology Major Project(2024ZD0802403)the National Natural Science Foundation of China(52307181,52220105002).
文摘Gas-insulated transmission lines and switchgears(GILs/GISs)are essential components that constitute ultra-high-voltage power transmission and transformation systems.Epoxy-based insulators,as core components,experience significant electric field distortions and consequent flashover faults.Since the 1980s,researchers have focused on utilizing dielectric functionally graded materials(FGMs)to improve the electric field distribution of insulators.The key research on FGMs for GIL/GIS insulators over the past half-century is reviewed.The development from bulk-FGMs to surface-FGMs,and eventually to multi-FGMs are outlined.Bulk-FGMs are typically used in AC systems.These materials provide a more uniform electric field distribution by creating a gradient in the relative permittivity within the insulator’s bulk.Surface-FGMs are commonly employed in DC systems,and they regulate the electric field by designing a surface conductivity gradient,thus preventing internal breakdowns that result from bulk conductivity gradients.In practice,GIL/GIS insulators are exposed to complex operating conditions,including AC,DC,and transient voltages,resulting in the development of multi-FGMs.These combine both conductivity and permittivity gradients,thus providing a comprehensive solution for suppressing both dynamic and static electric field distortions.An effective reference for researchers and industry professionals to support the transition of the research on FGM insulators from laboratory studies to practical engineering applications is provided.
基金This work was supported by the fund of the National Natural Science Foundation of China(Nos.22078184 and 52006130)China Postdoctoral Science Foundation(No.2019M653853XB)+3 种基金Opening Project of Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control(No.2019KF21)Natural science advance research foundation of Shaanxi University of Science and Technology(No.2018QNBJ-03)the Youth Innovation Team of Shaanxi Universities(No.21JP017)the Joint Research Funds of Department of Science and Technology of Shaanxi Province and Northwestern Polytechnical University(No.2020GXLH-Z-025).
文摘Due to their rich and adjustable porous network structure,paper-based functional materials have become a research hotspot in the field of energy storage.However,reasonably designing and making full use of the rich pore structure of paper-based materials to improve the electrochemical performance of paper-based energy storage devices still faces many challenges.Herein,we propose a structure engineering technique to develop a conductive integrated gradient porous paper-based(CIGPP)supercapacitor,and the kinetics process for the influence of gradient holes on the electrochemical performance of the CIGPP is investigated through experimental tests and COMSOL simulations.All results indicate that the gradient holes endow the CIGPP with an enhanced electrochemical performance.Specifically,the CIGPP shows a significant improvement in the specific capacitance,displays rich frequency response characteristics for electrolyte ions,and exhibits a good rate performance.Also,the CIGPP supercapacitor exhibits a low self-discharge and maintains a stable electrochemical performance in different electrolyte environments because of gradient holes.More importantly,when the CIGPP is used as a substrate to fabricate a CIGPP-PANI hybrid,it still maintains good electrochemical properties.In addition,the CIGPP supercapacitor also shows excellent stability and sensitivity for monitoring human motion and deaf-mute voicing,showing potential application prospects.This study provides a reference and feasible way for the design of structure-engineered integrated paper-based energy storage devices with outstanding comprehensive electrochemical performance.
