The return capsule of the trial version of China’s new-generation manned spaceship successfully returned to the Dongfeng landing site at 13:49 Beijing time on May 8, 2020. The mission of the experimental manned space...The return capsule of the trial version of China’s new-generation manned spaceship successfully returned to the Dongfeng landing site at 13:49 Beijing time on May 8, 2020. The mission of the experimental manned spaceship was completed successfully.展开更多
Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimiz...Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.展开更多
China's space lab Tiangong 2 successfully de-orbited and reentered the atmosphere in a controlled manner on July 19 after operating 1,036 days in space.A small amount of debris fell into a preset safety area in th...China's space lab Tiangong 2 successfully de-orbited and reentered the atmosphere in a controlled manner on July 19 after operating 1,036 days in space.A small amount of debris fell into a preset safety area in the South Pacific Ocean.展开更多
Liquid metals(LMs)are potential inorganic materials which could be applied in flexible and deformable electronics owing to their fluidity,low viscosity,high metallic conductivity,and low toxicity.However,recently repo...Liquid metals(LMs)are potential inorganic materials which could be applied in flexible and deformable electronics owing to their fluidity,low viscosity,high metallic conductivity,and low toxicity.However,recently reported sensing devices based on LMs required complex processes with high cost.Herein,a flexible three-dimensional(3 D)conductive network was prepared by coating LM droplets onto an electrospun thermoplastic polyurethane(TPU)fiber film.The LM is suspended between the TPU fibers and self-coalesces into a vertically buckled and laterally mesh-like structure,which provides good biocompatibility,conductivity,and stretchability simultaneously.The LM-TPU composite-filmbased flexible device demonstrates a multitude of desired features,such as a widely workable stretching range(0%-200%),sufficient sensitivity under stretching strain(gauge factor(GF)of 0.2 at 200%strain),and outstanding stability and durability(9000 cycles).In vitro biocompatibility experiments show that the LM-TPU composite film directly attached to the skin has excellent biocompatibility.Such strain sensorbased integrated monitoring systems could monitor human body motions in real time,such as muscle movement and joint motion,revealing application prospects in healthcare and human-machine interfacing.展开更多
By employing the Schauder fixed-point theorem, we establish new suffi- cient conditions for the controllability of impulsive functional boundary value problems.
A sufficient condition is obtained for a two-agent opinion dynamical system with pro-cessing delay to experience unconditional consensus. To this end, the dynamics proposed is transformed into a general class of delay...A sufficient condition is obtained for a two-agent opinion dynamical system with pro-cessing delay to experience unconditional consensus. To this end, the dynamics proposed is transformed into a general class of delay differential equation and asymptotic stability of the origin is then analyzed. It is also shown that increasing delay can prolong the time needed for the system to realize consensus and even induce a Hopf bifurcation.展开更多
By the time scales calculus theory and the Krasnoselskii fixed point theorem in cones, some sufficient conditions ensuring the existence of positive periodic solutions to a kind of Cohen-Grossberg neural networks on t...By the time scales calculus theory and the Krasnoselskii fixed point theorem in cones, some sufficient conditions ensuring the existence of positive periodic solutions to a kind of Cohen-Grossberg neural networks on time scales with delays are obtained.展开更多
文摘The return capsule of the trial version of China’s new-generation manned spaceship successfully returned to the Dongfeng landing site at 13:49 Beijing time on May 8, 2020. The mission of the experimental manned spaceship was completed successfully.
基金This work was supported by National Natural Science Foundation of China(51672308,51972025,61888102,62004187)Hebei Natural Science Foundation of Hebei(E2019208280).
文摘Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.
文摘China's space lab Tiangong 2 successfully de-orbited and reentered the atmosphere in a controlled manner on July 19 after operating 1,036 days in space.A small amount of debris fell into a preset safety area in the South Pacific Ocean.
基金supported by the National Natural Science Foundation of China(61625404,61888102,and 62174152)Foshan Innovative and Entrepreneurial Research Team Program(2018IT100031)。
文摘Liquid metals(LMs)are potential inorganic materials which could be applied in flexible and deformable electronics owing to their fluidity,low viscosity,high metallic conductivity,and low toxicity.However,recently reported sensing devices based on LMs required complex processes with high cost.Herein,a flexible three-dimensional(3 D)conductive network was prepared by coating LM droplets onto an electrospun thermoplastic polyurethane(TPU)fiber film.The LM is suspended between the TPU fibers and self-coalesces into a vertically buckled and laterally mesh-like structure,which provides good biocompatibility,conductivity,and stretchability simultaneously.The LM-TPU composite-filmbased flexible device demonstrates a multitude of desired features,such as a widely workable stretching range(0%-200%),sufficient sensitivity under stretching strain(gauge factor(GF)of 0.2 at 200%strain),and outstanding stability and durability(9000 cycles).In vitro biocompatibility experiments show that the LM-TPU composite film directly attached to the skin has excellent biocompatibility.Such strain sensorbased integrated monitoring systems could monitor human body motions in real time,such as muscle movement and joint motion,revealing application prospects in healthcare and human-machine interfacing.
基金supported by Natural Science Foundation of Shandong Province(ZR2014AM006)
文摘By employing the Schauder fixed-point theorem, we establish new suffi- cient conditions for the controllability of impulsive functional boundary value problems.
基金This work was jointly supported by National Natural Science Foundation of China (11401577) and Youth Top-notch Talent Support Program of NUDT (2014-2017).
文摘A sufficient condition is obtained for a two-agent opinion dynamical system with pro-cessing delay to experience unconditional consensus. To this end, the dynamics proposed is transformed into a general class of delay differential equation and asymptotic stability of the origin is then analyzed. It is also shown that increasing delay can prolong the time needed for the system to realize consensus and even induce a Hopf bifurcation.
基金supported by Basic Research Foundation of Naval Aeronautical Engineering Institute
文摘By the time scales calculus theory and the Krasnoselskii fixed point theorem in cones, some sufficient conditions ensuring the existence of positive periodic solutions to a kind of Cohen-Grossberg neural networks on time scales with delays are obtained.