Wind-induced vibration energy harvesting has a great potential for utilizing wind energy to supply power for low-powered devices.To improve the working performance of energy harvesters effectively,a suitable structura...Wind-induced vibration energy harvesting has a great potential for utilizing wind energy to supply power for low-powered devices.To improve the working performance of energy harvesters effectively,a suitable structural design is crucial.This paper proposes a dual-beam piezo-magneto-elastic wake-induced vibration energy harvesting system to enhance the functional performance of aeroelastic energy harvesters in environments with variable wind speeds.The system contains two piezoelectric beams coupled by magnets(forming upstream and downstream energy harvesters),and each beam is attached with a foam cylinder.A corresponding dynamic model is provided,and output characteristics are obtained at different wind speeds.Results and experimental verification indicate that both upstream and downstream energy harvesters can realize efficient energy harvesting.When the wind speed exceeds a certain critical value,the amplitudes of the system’s displacement and voltage are high.The wind speed threshold value is approximately 1.25 m/s.When the wind speed and magnet spacing are 10.2 m/s and 20 mm,respectively,the output power of the system reaches 4.9×10^(−4)W.Moreover,the wind speed threshold value of the proposed system can be adjusted by an equivalent nonlinear restoring force.展开更多
The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic in...The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic interference.In this study,the optical rotation angle detection system based on polarization balance detection is utilized to realize the alkali-atom density real-time measurement without affecting magnetic field measurement.We discovered that there exists an optimal frequency detuning of the probe light,which offers the highest sensitivity in alkali-atom density measurement and the lowest susceptibility to temperature fluctuations in terms of the scale factor.In contrast to conventional light absorption measurements based on pump light,this method demonstrated a threefold improvement in alkali-atom density measurement sensitivity while remaining immune to ambient magnetic fields and incident light intensity fluctuations.Furthermore,we utilized this method to achieve closed-loop temperature control with an accuracy of 0.04℃.展开更多
In this paper, we propose a single-port dual-beam leaky-wave antenna(LWA) in the terahertz(THz) band based on a composite spoof surface plasmon polariton(SSPP) waveguide. The antenna can generate three independent tra...In this paper, we propose a single-port dual-beam leaky-wave antenna(LWA) in the terahertz(THz) band based on a composite spoof surface plasmon polariton(SSPP) waveguide. The antenna can generate three independent transmission channels by exciting two independent modes inherent to hole and groove structures, respectively. By periodic modulation of the hole and groove structures, we achieve dual-beam scanning through a broad radiation angle using only the -1st space harmonics of the two modes, hence avoiding the instability of the -2rd space harmonic. Within the operating frequency range of 0.62—0.85 THz, the gain ranges from 13.5 d Bi to 17 d Bi for the backward beam, and from 6 d Bi to 11.8 d Bi for the forward beam. The antenna can accomplish continuous backward beam through broadside to forward beam scanning with a total scanning range of 116° and an average efficiency of about 92%. The antenna exhibits a great potential in the design of multi-transceiver radar system in the THz band and multi-beam LWAs.展开更多
Dislocation loop and gas bubble evolution in tungsten were in-situ investigated under 30 keV H_(2)^(+)and He^(+)dual-beam irra-diation at 973 K and 1173 K.The average size and number density of dislocation loops and g...Dislocation loop and gas bubble evolution in tungsten were in-situ investigated under 30 keV H_(2)^(+)and He^(+)dual-beam irra-diation at 973 K and 1173 K.The average size and number density of dislocation loops and gas bubbles were obtained as a function of irradiation dose.The quantitative calculation and analysis of the migration distance of 1/2<111>loops at low irradiation dose indicated that the main mechanism of the formation of<100>loops should be attributed to the high-density helium cluster inducement mechanism,instead of the 1/2<111>loop reaction mechanism.H2+and He+dual-beam irradiation induced the formation of<100>loops and 1/2<111>loops,while increasing the irradiation temperature would increase<100>loop percentage.The percentage of<100>loops was approximately 18.6%at 973 K and increased to 22.9%at 1173 K.The loop reaction between two 1/2<111>loops to form a large-sized 1/2<111>loop was in-situ observed,which induced not only the decrease of the number of 1/2<111>loops but also the significant increase of their sizes.The<100>loops impeded the movement of dislocation line and tended to escape from it instead of being absorbed.With the increase of irradiation dose,the yield strength increment(Δ_(σloop))caused by the change of loop size and density increased first and then decreased slightly,while the yield strength increment(Δ_(σbubble))caused by the change of bubble size and density always increased.Meanwhile,within the current irradiation dose range,Δ_(σloop)was much larger thanΔ_(σbubble).展开更多
A stimulated emission depletion is capable of breaking the diffraction limit by exciting fluorescent molecules with a solid Gaussian beam and quenching the excited molecules with another donut beam through stimulated ...A stimulated emission depletion is capable of breaking the diffraction limit by exciting fluorescent molecules with a solid Gaussian beam and quenching the excited molecules with another donut beam through stimulated emission.The coincidence degree of these two beams in three dimensions will significantly influence the spatial resolution of the microscope.However,the conventional alignment approach based on raster scanning of gold nanoparticles by the two laser beams separately suffers from a mismatch between fluorescence and scattering modes.To circumvent the above problems,we demonstrate a fast alignment design by scanning the second beam over the fabricated sample,which is made of aggregation-induced emission(AIE)dye resin.The relative positions of solid and donut laser beams can be represented by the fluorescent AIE from the labeled spots in the dye resin.This design achieves ultra-high resolutions of 22 nm in the x/y relative displacement and 27 nm in the z relative displacement for fast spatial matching of the two laser beams.This study has potential applications in scenarios that require the spatial matching of multiple laser beams,and the field of views of different objectives,for example,in a microscope with high precision.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52161135106)the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant No.JCYJ201908061536-15091)+4 种基金the International Science and Technology Cooperation Project of Guangdong Province(Grant No.2021A0505030012)the Innovation Capability Support Plan of Shaanxi Province(Grant No.2020KJXX-021)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Grant No.CX2022001)the 111 Project(Grant No.BP0719007)supported by the National Science Centre,Poland under the project SHENG-2(Grant No.2021/40/Q/ST8/00362)。
文摘Wind-induced vibration energy harvesting has a great potential for utilizing wind energy to supply power for low-powered devices.To improve the working performance of energy harvesters effectively,a suitable structural design is crucial.This paper proposes a dual-beam piezo-magneto-elastic wake-induced vibration energy harvesting system to enhance the functional performance of aeroelastic energy harvesters in environments with variable wind speeds.The system contains two piezoelectric beams coupled by magnets(forming upstream and downstream energy harvesters),and each beam is attached with a foam cylinder.A corresponding dynamic model is provided,and output characteristics are obtained at different wind speeds.Results and experimental verification indicate that both upstream and downstream energy harvesters can realize efficient energy harvesting.When the wind speed exceeds a certain critical value,the amplitudes of the system’s displacement and voltage are high.The wind speed threshold value is approximately 1.25 m/s.When the wind speed and magnet spacing are 10.2 m/s and 20 mm,respectively,the output power of the system reaches 4.9×10^(−4)W.Moreover,the wind speed threshold value of the proposed system can be adjusted by an equivalent nonlinear restoring force.
文摘The alkali-atom density measurement method based on light absorption is highly suitable for a spin-exchange relaxationfree(SERF)atomic magnetometer because of its high-precision measurement and complete nonmagnetic interference.In this study,the optical rotation angle detection system based on polarization balance detection is utilized to realize the alkali-atom density real-time measurement without affecting magnetic field measurement.We discovered that there exists an optimal frequency detuning of the probe light,which offers the highest sensitivity in alkali-atom density measurement and the lowest susceptibility to temperature fluctuations in terms of the scale factor.In contrast to conventional light absorption measurements based on pump light,this method demonstrated a threefold improvement in alkali-atom density measurement sensitivity while remaining immune to ambient magnetic fields and incident light intensity fluctuations.Furthermore,we utilized this method to achieve closed-loop temperature control with an accuracy of 0.04℃.
基金supported by the Natural Science Foundation of Tianjin (No.19JCYBJC16100)the Tianjin Innovation and Entrepreneurship Training Program (No.202210060027)。
文摘In this paper, we propose a single-port dual-beam leaky-wave antenna(LWA) in the terahertz(THz) band based on a composite spoof surface plasmon polariton(SSPP) waveguide. The antenna can generate three independent transmission channels by exciting two independent modes inherent to hole and groove structures, respectively. By periodic modulation of the hole and groove structures, we achieve dual-beam scanning through a broad radiation angle using only the -1st space harmonics of the two modes, hence avoiding the instability of the -2rd space harmonic. Within the operating frequency range of 0.62—0.85 THz, the gain ranges from 13.5 d Bi to 17 d Bi for the backward beam, and from 6 d Bi to 11.8 d Bi for the forward beam. The antenna can accomplish continuous backward beam through broadside to forward beam scanning with a total scanning range of 116° and an average efficiency of about 92%. The antenna exhibits a great potential in the design of multi-transceiver radar system in the THz band and multi-beam LWAs.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 11975191, U1832112, and U1967211)
文摘Dislocation loop and gas bubble evolution in tungsten were in-situ investigated under 30 keV H_(2)^(+)and He^(+)dual-beam irra-diation at 973 K and 1173 K.The average size and number density of dislocation loops and gas bubbles were obtained as a function of irradiation dose.The quantitative calculation and analysis of the migration distance of 1/2<111>loops at low irradiation dose indicated that the main mechanism of the formation of<100>loops should be attributed to the high-density helium cluster inducement mechanism,instead of the 1/2<111>loop reaction mechanism.H2+and He+dual-beam irradiation induced the formation of<100>loops and 1/2<111>loops,while increasing the irradiation temperature would increase<100>loop percentage.The percentage of<100>loops was approximately 18.6%at 973 K and increased to 22.9%at 1173 K.The loop reaction between two 1/2<111>loops to form a large-sized 1/2<111>loop was in-situ observed,which induced not only the decrease of the number of 1/2<111>loops but also the significant increase of their sizes.The<100>loops impeded the movement of dislocation line and tended to escape from it instead of being absorbed.With the increase of irradiation dose,the yield strength increment(Δ_(σloop))caused by the change of loop size and density increased first and then decreased slightly,while the yield strength increment(Δ_(σbubble))caused by the change of bubble size and density always increased.Meanwhile,within the current irradiation dose range,Δ_(σloop)was much larger thanΔ_(σbubble).
基金supported by the National Key Research and Development Program of China(No.2018YFB0704103)National Natural Science Foundation of China(No.62175153)。
文摘A stimulated emission depletion is capable of breaking the diffraction limit by exciting fluorescent molecules with a solid Gaussian beam and quenching the excited molecules with another donut beam through stimulated emission.The coincidence degree of these two beams in three dimensions will significantly influence the spatial resolution of the microscope.However,the conventional alignment approach based on raster scanning of gold nanoparticles by the two laser beams separately suffers from a mismatch between fluorescence and scattering modes.To circumvent the above problems,we demonstrate a fast alignment design by scanning the second beam over the fabricated sample,which is made of aggregation-induced emission(AIE)dye resin.The relative positions of solid and donut laser beams can be represented by the fluorescent AIE from the labeled spots in the dye resin.This design achieves ultra-high resolutions of 22 nm in the x/y relative displacement and 27 nm in the z relative displacement for fast spatial matching of the two laser beams.This study has potential applications in scenarios that require the spatial matching of multiple laser beams,and the field of views of different objectives,for example,in a microscope with high precision.
