In recent years, the research and development of piezoelectric pumps have become an increasingly popular topic. Minimization, structure simplification and stronger output become the focus of piezoelectric pumps’ rese...In recent years, the research and development of piezoelectric pumps have become an increasingly popular topic. Minimization, structure simplification and stronger output become the focus of piezoelectric pumps’ research due to its possible application in MEMS technology. The valveless fishtailing piezoelectric pump, neither a volumetric nor a rotating pump, was invented according to the bionics of fish swimming. With assumption that the head of the fish is fixed while its tail is swinging, fluid would flow toward the end of the tail, achieving the function of a valveless pump. This type of pumps creates a new branch for the piezoelectric pump research, which is proposed for the first time in this paper. The relationship between the flow rates and vibrating frequencies was derived from the interaction between the vibrator and fluid. Numerical simulations with FEM software were conducted to study the first and second vibration modes of the piezoelectric vibrator. The results showed that the maximum amplitude of the vibrator was 0.9 mm at the frequency of 76 Hz for the first vibration mode, while the maximum amplitude of the vibrator was 0.22 mm at the frequency of 781 Hz for the second vibration mode. Experiments were conducted with the Doppler laser vibration measurement system, and the results were compared to those of the FEM simulation. It was shown that in the first vibration mode the piezoelectric vibrator reached its maximum amplitude of about 0.9 mm at the driving frequency of 49 Hz, which gives the flow rate of 2.0 mL/min, in the second vibration mode, the maximum amplitude was about 0.25 mm at the frequency of 460 Hz with the flow rate being 6.4 mL/min.展开更多
To adapt to the low-velocity water flow closely related to human life,the natural energy can be efficiently harvested and used to power monitoring devices.Herein,a triboelectric soft fishtail(TE-SFT)driven by flow-ind...To adapt to the low-velocity water flow closely related to human life,the natural energy can be efficiently harvested and used to power monitoring devices.Herein,a triboelectric soft fishtail(TE-SFT)driven by flow-induced vibration(FIV)effect is proposed based on the soft material synthesis technology.Specifically,inspired by the fishtail fin,a bluff body with the cross-section of fishtail-shaped is designed,and has a preferable vortex effect by fluid simulation.In power generation part,the triboelectric nanogenerator(TENG)is designed to act as an inertial pendulum structure by geometric method.Under the FIV effect,the TESFT driven by fishtail-shaped bluff body swings like a fish in the water and then brings the inertial pendulum to acquire the oscillation for harvesting energy from low-velocity water flow.The TE-SFT attains an open-circuit voltage(VOC)of 200 V to 313 V at the flow velocities of 0.24 to 0.89 m/s.Additionally,after 30 days of water immersion,the VOC of TE-SFT retains 96.81%.In demonstration,the TE-SFT is applied to power the temperature and humidity sensor through harvesting water flow energy.This work also provides a way for self-powered system based on the TENG and soft bionic fish in water environment.展开更多
The Y 1-xHo xBa-2Cu-3O y superconductors were fabricated by the powder melting process (PMP) method and the magnetic hysteresis loops of these samples were measured at different temperatures by a SQUID magnetometer (u...The Y 1-xHo xBa-2Cu-3O y superconductors were fabricated by the powder melting process (PMP) method and the magnetic hysteresis loops of these samples were measured at different temperatures by a SQUID magnetometer (up to 7 T). Critical current density was calculated by the Bean critical state model. The results indicate that the fishtail effect is observed in Y 0.6Ho 0.4Ba-2Cu-3O y below 60 K, while no fishtail can be found in Y 0.8Ho 0.2Ba-2Cu-3O y until 30 K. The peak field at which J c reaches its maximum decreases with the increasing magnetic field. In the Y 0.6Ho 0.4Ba-2Cu-3O y sample, the fishtail effect disappears when the temperature is raised to 77 K. In addition, after the Y 0.6Ho 0.4Ba-2Cu-3O y sample was re-sintered at high temperature for a long time, the fishtail can be found in two field directions (H∥C and H⊥C). It is considered that the paramagnetism in the sample may be responsible for the fishtail effect in Ho-added YBCO. Also, the cation disorder created by Ho addition may be another reason for the fishtail.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50775109, 51075201, 50735002)Open Foundation for the National Key Laboratory of the Numerical Manufacturing Equip-ment and Technology (Grant No. DMETKF2009002)
文摘In recent years, the research and development of piezoelectric pumps have become an increasingly popular topic. Minimization, structure simplification and stronger output become the focus of piezoelectric pumps’ research due to its possible application in MEMS technology. The valveless fishtailing piezoelectric pump, neither a volumetric nor a rotating pump, was invented according to the bionics of fish swimming. With assumption that the head of the fish is fixed while its tail is swinging, fluid would flow toward the end of the tail, achieving the function of a valveless pump. This type of pumps creates a new branch for the piezoelectric pump research, which is proposed for the first time in this paper. The relationship between the flow rates and vibrating frequencies was derived from the interaction between the vibrator and fluid. Numerical simulations with FEM software were conducted to study the first and second vibration modes of the piezoelectric vibrator. The results showed that the maximum amplitude of the vibrator was 0.9 mm at the frequency of 76 Hz for the first vibration mode, while the maximum amplitude of the vibrator was 0.22 mm at the frequency of 781 Hz for the second vibration mode. Experiments were conducted with the Doppler laser vibration measurement system, and the results were compared to those of the FEM simulation. It was shown that in the first vibration mode the piezoelectric vibrator reached its maximum amplitude of about 0.9 mm at the driving frequency of 49 Hz, which gives the flow rate of 2.0 mL/min, in the second vibration mode, the maximum amplitude was about 0.25 mm at the frequency of 460 Hz with the flow rate being 6.4 mL/min.
基金The authors are grateful for the support from the National Key Research&Development Project from the Minister of Science and Technology(Nos.2021YFA1201601 and 2021YFA1201604)the Beijing Natural Science Foundation(No.3222023).
文摘To adapt to the low-velocity water flow closely related to human life,the natural energy can be efficiently harvested and used to power monitoring devices.Herein,a triboelectric soft fishtail(TE-SFT)driven by flow-induced vibration(FIV)effect is proposed based on the soft material synthesis technology.Specifically,inspired by the fishtail fin,a bluff body with the cross-section of fishtail-shaped is designed,and has a preferable vortex effect by fluid simulation.In power generation part,the triboelectric nanogenerator(TENG)is designed to act as an inertial pendulum structure by geometric method.Under the FIV effect,the TESFT driven by fishtail-shaped bluff body swings like a fish in the water and then brings the inertial pendulum to acquire the oscillation for harvesting energy from low-velocity water flow.The TE-SFT attains an open-circuit voltage(VOC)of 200 V to 313 V at the flow velocities of 0.24 to 0.89 m/s.Additionally,after 30 days of water immersion,the VOC of TE-SFT retains 96.81%.In demonstration,the TE-SFT is applied to power the temperature and humidity sensor through harvesting water flow energy.This work also provides a way for self-powered system based on the TENG and soft bionic fish in water environment.
文摘The Y 1-xHo xBa-2Cu-3O y superconductors were fabricated by the powder melting process (PMP) method and the magnetic hysteresis loops of these samples were measured at different temperatures by a SQUID magnetometer (up to 7 T). Critical current density was calculated by the Bean critical state model. The results indicate that the fishtail effect is observed in Y 0.6Ho 0.4Ba-2Cu-3O y below 60 K, while no fishtail can be found in Y 0.8Ho 0.2Ba-2Cu-3O y until 30 K. The peak field at which J c reaches its maximum decreases with the increasing magnetic field. In the Y 0.6Ho 0.4Ba-2Cu-3O y sample, the fishtail effect disappears when the temperature is raised to 77 K. In addition, after the Y 0.6Ho 0.4Ba-2Cu-3O y sample was re-sintered at high temperature for a long time, the fishtail can be found in two field directions (H∥C and H⊥C). It is considered that the paramagnetism in the sample may be responsible for the fishtail effect in Ho-added YBCO. Also, the cation disorder created by Ho addition may be another reason for the fishtail.
